Revisions to the California State Implementation Plan and Revision to the Definition of Volatile Organic Compounds (VOC)-Removal of VOC Exemptions for California's Aerosol Coating Products Reactivity-Based Regulation, 1640-1654 [05-346]
Download as PDF
1640
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 51 and 52
[OAR–2003–0200; FRL–7857–6]
Revisions to the California State
Implementation Plan and Revision to
the Definition of Volatile Organic
Compounds (VOC)—Removal of VOC
Exemptions for California’s Aerosol
Coating Products Reactivity-Based
Regulation
Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
AGENCY:
SUMMARY: The EPA is proposing to
approve a new consumer products
regulation as part of the California State
Implementation Plan (SIP) for ozone
under the Clean Air Act (CAA) as
amended in 1990. This California
regulation adopts an innovative
approach to reduce ozone formation
from volatile organic compounds (VOC)
in aerosol coating products. The EPA is
also proposing to approve the use of
California’s Tables of Maximum
Incremental Reactivity (MIR) to allow
implementation of the new regulation in
California. We are also proposing to
revise EPA’s definition of VOCs so that
compounds which we previously
identified as negligibly reactive and
exempt from EPA’s regulatory definition
of VOCs will now count towards a
product’s reactivity-based VOC limit for
the purpose of California’s aerosol
coatings regulation. We are taking
comments on this proposal and we plan
to follow with a final action.
DATES: Comments must be received on
or before March 8, 2005.
ADDRESSES: Submit your comments,
identified by Docket ID No. OAR–2003–
0200, by one of the following methods:
• Federal eRulemaking Portal: https://
www.regulations.gov. Follow the on-line
instructions for submitting comments.
• Agency Web site: https://
www.epa.gov/edocket. EDOCKET, EPA’s
electronic public docket and comment
system, is EPA’s preferred method for
receiving comments. Follow the on-line
instructions for submitting comments.
• E-mail: a-and-r-Docket@epa.gov.
• Fax: 202–566–1741.
• Mail: OAR Docket: OAR–2003–
0200, Environmental Protection Agency,
Mailcode: 6102T, 1200 Pennsylvania
Ave., NW., Washington, DC 20460.
• Hand Delivery: EPA/DC, Public
Reading Room, Room B102, EPA West
Building, 1301 Constitution Avenue,
NW., Washington, DC. Such deliveries
are only accepted during the Docket’s
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
normal hours of operation, and special
arrangements should be made for
deliveries of boxed information.
Instructions: Direct your comments to
Docket ID No. OAR–2003–0200. EPA’s
policy is that all comments received
will be included in the public docket
without change and may be made
available online at https://www.epa.gov/
edocket, including any personal
information provided, unless the
comment includes information claimed
to be Confidential Business Information
(CBI) or other information whose
disclosure is restricted by statute. Do
not submit information that you
consider to be CBI or otherwise
protected through EDOCKET,
regulations.gov, or e-mail. The EPA
EDOCKET and the federal
regulations.gov websites are
‘‘anonymous access’’ systems, which
means EPA will not know your identity
or contact information unless you
provide it in the body of your comment.
If you send an e-mail comment directly
to EPA without going through
EDOCKET or regulations.gov, your email address will be automatically
captured and included as part of the
comment that is placed in the public
docket and made available on the
Internet. If you submit an electronic
comment, EPA recommends that you
include your name and other contact
information in the body of your
comment and with any disk or CD-ROM
you submit. If EPA cannot read your
comment due to technical difficulties
and cannot contact you for clarification,
EPA may not be able to consider your
comment. Electronic files should avoid
the use of special characters, any form
of encryption, and be free of any defects
or viruses. For additional information
about EPA’s public docket visit
EDOCKET on-line or see the Federal
Register of May 31, 2002 (67 FR 38102).
For additional instructions on
submitting comments, go to Unit I of the
SUPPLEMENTARY INFORMATION section of
this document.
Docket: All documents in the docket
are listed in the EDOCKET index at
https://www.epa.gov/edocket. Although
listed in the index, some information is
not publicly available, i.e., CBI or other
information whose disclosure is
restricted by statute. Certain other
material, such as copyrighted material,
is not placed on the Internet and will be
publicly available only in hard copy
form. Publicly available docket
materials are available either
electronically in EDOCKET or in hard
copy at the OAR Docket, OAR–2003–
0200, EPA/DC, EPA West, Room B102,
1301 Constitution Ave., NW.,
Washington, DC. The Public Reading
PO 00000
Frm 00002
Fmt 4701
Sfmt 4702
Room is open from 8:30 a.m. to 4:30
p.m., Monday through Friday, excluding
legal holidays. The telephone number
for the Public Reading Room is (202)
566–1744, and the telephone number for
the OAR Docket is (202) 566–1742.
FOR FURTHER INFORMATION CONTACT:
Stanley Tong, Rulemaking Office (AIR–
4), Environmental Protection Agency,
Region IX, 75 Hawthorne St., San
Francisco, CA 94105; telephone
number: (415) 947–4122; fax number:
(415) 947–3579; e-mail address:
tong.stanley@epa.gov.
SUPPLEMENTARY INFORMATION:
I. General Information
A. What Should I Consider as I Prepare
My Comments for EPA?
1. Submitting CBI. Do not submit this
information to EPA through EDOCKET,
regulations.gov or e-mail. Clearly mark
the part or all of the information that
you claim to be CBI. For CBI
information in a disk or CD ROM that
you mail to EPA, mark the outside of the
disk or CD ROM as CBI and then
identify electronically within the disk or
CD ROM the specific information that is
claimed as CBI). In addition to one
complete version of the comment that
includes information claimed as CBI, a
copy of the comment that does not
contain the information claimed as CBI
must be submitted for inclusion in the
public docket. Information so marked
will not be disclosed except in
accordance with procedures set forth in
40 CFR part 2.
2. Tips for Preparing Your Comments.
When submitting comments, remember
to:
i. Identify the rulemaking by docket
number and other identifying
information (subject heading, Federal
Register date and page number).
ii. Follow directions—The agency
may ask you to respond to specific
questions or organize comments by
referencing a Code of Federal
Regulations (CFR) part or section
number.
iii. Explain why you agree or disagree;
suggest alternatives and substitute
language for your requested changes.
iv. Describe any assumptions and
provide any technical information and/
or data that you used.
v. If you estimate potential costs or
burdens, explain how you arrived at
your estimate in sufficient detail to
allow for it to be reproduced.
vi. Provide specific examples to
illustrate your concerns, and suggest
alternatives.
vii. Explain your views as clearly as
possible, avoiding the use of profanity
or personal threats.
E:\FR\FM\07JAP2.SGM
07JAP2
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
viii. Make sure to submit your
comments by the comment period
deadline identified.
ix. Please strictly limit comments to
the subject matter of this proposal, the
scope of which is discussed below.
Please identify the section/subsection
on which you are commenting so we
can group similar comments together
and better understand the context of
your comment.
x. EPA requests that you also send a
copy of your comments to: Andrew
Steckel, Rulemaking Office Chief (AIR–
4), U.S. Environmental Protection
Agency, Region IX, 75 Hawthorne
Street, San Francisco, CA 94105–3901.
3. Docket Copying Costs. A reasonable
fee may be charged for copying.
B. How Do I Request a Public Hearing?
If you wish to request a public hearing
to submit comments concerning this
proposal please contact Mr. Stanley
Tong, Rulemaking Office (AIR–4), U.S.
Environmental Protection Agency, 75
Hawthorne Street, San Francisco, CA
94105, telephone (415) 947–4122.
Requests for a public hearing must be
made by January 27, 2005. The EPA will
publish a notice of a hearing, if a
hearing is requested, in the Federal
Register. Because the State has already
held a public notice and comment
period for its aerosol coatings rule, any
EPA hearing will be strictly limited to
the proposed EPA approval of the rule
and its inclusion in the California SIP
and to the proposed change in the
definition of VOCs for 40 CFR 51.100(s).
The hearing will not cover the reactivity
limits or other specifics of California’s
rule. If a public hearing is requested, it
will be held near our Region IX office
in San Francisco, CA.
C. Throughout This Document, ‘‘We,’’
‘‘Us’’ and ‘‘Our’’ Refer to EPA
D. How Can I Get Copies of This
Document and Other Related
Information?
1. In addition to accessing the official
public docket at https://www.epa.gov/
edocket/, you can also inspect copies of
the submitted SIP revision at our Region
IX office during normal business hours.
EPA requests that you contact the
person listed in the FOR FURTHER
INFORMATION CONTACT section to
schedule your inspection. You may also
see copies of the submitted SIP revision
during normal business hours by
appointment at the California Air
Resources Board, Stationary Source
Division, Rule Evaluation Section, 1001
‘‘I’’ Street, Sacramento, CA 95814.
2. A copy of California’s aerosol
coating products regulation can also be
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
downloaded from the following internet
addresses. Please be advised that these
are not EPA Web sites and may not
contain the same version of the
regulations that were submitted to EPA.
https://www.arb.ca.gov/consprod/regs/
aeropnt.pdf https://www.arb.ca.gov/
consprod/regs/Aeropnt.doc
Table of Contents
I. The State’s Submittal.
A. What regulations did the State submit?
B. Are there other versions of this
regulation?
C. What is the purpose of the submitted
CARB regulation?
III. EPA’s Evaluation and Action.
A. How is EPA evaluating the regulation?
B. Does the regulation meet the evaluation
criteria?
C. Public comment and final action.
IV. Background Information.
A. Why was this regulation submitted?
B. What is photochemical reactivity?
C. Why is use of the relative reactivity
concept appropriate in California’s
aerosol coatings rule?
D. Are California’s relative reactivity-based
regulations appropriate for areas outside
of California?
E. How will the effectiveness of this
reactivity-based program be evaluated?
F. How has CARB addressed concerns
about air toxics and ozone-depleting
substances?
G. What changes in enforcement strategies
will likely occur due to this relative
reactivity-based regulation?
IV. Summary of CARB’s Aerosol Coatings
Regulation.
A. What does CARB’s regulation require?
V. Future Actions.
A. What action will be taken to determine
if this reactivity-based regulation is
effective?
B. How will future uses of relative
reactivity be evaluated?
VI. Statutory and Executive Order Reviews.
1641
criteria in 40 CFR Part 51, Appendix V,
as required before formal EPA review.
B. Are There Other Versions of This
Regulation?
There is no previous version of the
aerosol coating products regulation
approved by EPA into the SIP, although
CARB adopted an earlier version of this
regulation on March 23, 1995, and
submitted it to us on December 18,
1998. On November 19, 1998, CARB
adopted amendments to this earlier
regulation. The CARB did not submit
these amendments to us as a SIP
revision. There is no previous standalone version of the Tables of MIR
values in the SIP applicable to aerosol
coatings. Today, we are proposing
approval of the CARB aerosol coatings
rule submitted to us on March 13, 2002.
While we can act on only the most
recently submitted version of this
regulation, we have reviewed materials
CARB provided with the previous SIP
submittals for informational purposes.
Thus, this version of the aerosol
coatings rule replaces the earlier
versions developed by CARB and, if we
approve it, will be the first such rule in
the California SIP.
C. What Is the Purpose of the Submitted
CARB Regulation?
The regulation covers aerosol
coatings, aerosol clear coatings, and
aerosol stains. It applies to any person
who sells, supplies, offers for sale,
applies, or manufactures for use in
California any aerosol coating subject to
the limits in the regulation. The
regulation imposes reactivity-based
VOC limits on these products for
purposes of reducing ozone caused by
VOC emissions.
In the current SIP submittal, CARB
I. The State’s Submittal
has developed a new approach for
A. What Regulations Did the State
regulating VOC emissions from aerosol
Submit?
coatings. Traditionally, the VOC
emissions from aerosol and other
Table 1 lists the regulations addressed coatings have been controlled by
by this proposal with the date that they
limiting the mass of all VOCs in a
were adopted and submitted to EPA by
product, and VOC content limits of
the California Air Resources Board
aerosol coatings were expressed as a
(CARB).
maximum percent by mass of all VOC.
The new approach taken by CARB
TABLE 1.—SUBMITTED REGULATIONS incorporates the concept of VOC
photochemical reactivity. This concept
Regulation title
Adopted
Submitted
relies on the fact that the same weight/
amount of some VOCs (e.g., xylene) has
Aerosol Coating
Products ........
5/1/2001
3/13/2002 the potential to form more ozone, or to
form ozone more quickly, than the same
Tables of Maximum Increweight/amount of other VOCs (e.g.,
mental Reacpropane) once they are emitted into the
tivity (MIR)
ambient air under the same conditions.
Values ...........
5/1/2001
3/13/2002
The CARB estimates that its previous
mass-based VOC control rule for aerosol
On May 7, 2002, we found that this
coatings resulted in statewide aerosol
submittal meets the completeness
coating VOC emissions reductions of 9
PO 00000
Frm 00003
Fmt 4701
Sfmt 4702
E:\FR\FM\07JAP2.SGM
07JAP2
1642
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
tons per day (tpd) from the 1989
baseline estimated VOC emissions of 30
tpd of VOC. The CARB calculates that
the new reactivity-based aerosol
coatings rule in the current submittal
would achieve the ‘‘equivalent’’ of an
additional 3.1 tpd of VOC mass-based
reductions statewide. In other words,
CARB estimates that this rule will
achieve reactivity-based VOC reductions
that would be the equivalent of 12.1
tons of mass-based VOC reductions from
the 1989 baseline, measured in terms of
ozone reduction. The CARB intends its
new regulation to encourage
manufacturers to reduce use of VOCs
with higher reactivity, thereby achieving
more ozone reductions than through
traditional VOC mass-based regulations.
III. EPA’s Evaluation and Action
A. How Is EPA Evaluating the
Regulation?
Generally, SIP regulations must be
enforceable (see section 110(a)(2)(A) of
the CAA), must at a minimum require
Reasonably Available Control
Technology (RACT) and Reasonably
Available Control Measures (RACM) in
nonattainment areas (see, for example,
sections 172(c)(1), 182(a)(2)(A) and
182(b)(2)), must not interfere with
attainment and reasonable further
progress or any other applicable
requirement of the CAA, and must
achieve the pollution reduction
requirements of the CAA (see section
110(l)). The CARB’s aerosol coatings
regulation applies to both ozone
attainment and non-attainment areas
statewide. Because this regulation
covers nonmajor area sources that are
not covered by a Control Techniques
Guidelines (CTG) document, it is not
subject to the RACT requirements for
ozone nonattainment areas (CAA,
section 182(b)(2)).
Guidance and policy documents that
we used to help evaluate enforceability
requirements includes: Issues Relating
to VOC Regulation Cutpoints,
Deficiencies, and Deviations;
Clarification to Appendix D of
November 24, 1987 Federal Register,’’
(Blue Book), May 25, 1988, (revised
1/11/90), Office of Air Quality Planning
and Standards. We also relied on several
technical reports and journals to
evaluate CARB’s SIP submittal. These
reports and journals are referenced in
footnotes in the body of this proposal
and are included in the docket for this
proposal.
B. Does the Regulation Meet the
Evaluation Criteria?
We believe that the aerosol coatings
rule will improve the SIP by
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
establishing stringent VOC limits for
this product category, by improving
enforcement through labeling and
reporting requirements, and by creating
an incentive for the use of solvents with
relatively low contribution to ozone
formation. The regulation is generally
consistent with relevant policy and
guidance regarding enforceability. Our
approval of the rule would also be
consistent with CAA section 110(l),
because there is no prior version of the
aerosol coatings regulation in the SIP
and ozone reductions resulting from the
approval of this regulation into the SIP
will help in the State’s efforts to achieve
attainment with the national ambient air
quality standard (NAAQS) for ozone.
RACT requirements do not apply to the
source category covered by the CARB
rule because RACT applies to major
stationary sources in nonattainment
areas and source categories covered by
a CTG. Because of their widespread use
in relatively small amounts, aerosol
coatings are considered area sources
rather than major stationary sources.
EPA has not issued a CTG or a rule for
this category. However, even though
federal RACT or consumer product
requirements do not yet apply, CARB
took the initiative in 1995 to go beyond
basic federally mandated VOC reduction
requirements by adopting an aerosol
coatings regulation with two tiers of
aggressive mass-based VOC limits. In its
current SIP submittal, CARB is
amending its existing regulation by
replacing the mass-based limits with
reactivity-based limits intended to
achieve additional ozone reduction
benefits.
Although CARB’s existing mass-based
aerosol coatings regulation has
significantly reduced emissions from
aerosol coatings, CARB has concluded
that more reductions are needed to help
reduce the high ozone concentrations in
Southern California and the Central
Valley. The CARB also believes that
some VOC mass-based limits in the
previous version of the rule presented
particularly difficult reformulation
challenges for manufacturers of waterbased coatings,1 and the State
concluded that it may not be feasible to
achieve additional VOC reductions from
a traditional VOC mass-based program.
The current SIP submittal relies on the
relative reactivity concept, that is, the
fact that individual species of VOC react
in the atmosphere to form different
amounts of ozone or to form ozone at
different rates. The CARB hopes to
target VOC emission reductions to better
control a product’s contribution to
ozone formation by encouraging
reductions of higher reactivity VOCs,
rather than by treating all VOCs in a
product alike through a mass-based rule.
The submitted regulation therefore
consists of reactivity-based limits that
replace the existing mass-based VOC
limits for aerosol spray coatings.
Although EPA is supportive of
reactivity-based programs, we recognize
that they may be more complex to
develop, enforce, and evaluate than
mass-based programs. As a result, it is
particularly important for us to evaluate
the State agency’s ability to implement
such programs. The CARB has
addressed these concerns partly through
an extensive public process spanning
over 3 years in the development of the
aerosol coatings rule. The CARB held
eight public workshops and over 20
meetings with industry, leading
scientists, local air districts, and EPA.
The CARB also gathered detailed
information on the sales and
composition of aerosol coatings, funded
extensive research on VOC reactivity
scales and their applicability to
environmental conditions in California,
and took steps intended to ensure that
no backsliding would occur from
adoption of the relative-reactivity
approach. To account for potential
changes in MIR values as scientific
knowledge improves, CARB also
committed to improve and update its
program by including in its Board
resolution 2 the provision ‘‘[t]o review
the Tables of Maximum Incremental
Reactivity (MIR) Values 18 months after
the effective date of the amendments,
and every 18 months thereafter, to
determine if modifications to the MIR
values are warranted.’’ The CARB will
also ‘‘[r]eview the reactivity-based limits
before January 1, 2007 to determine if
modifications are necessary to reflect
changes to the MIR values and return to
the Board with any recommended
modifications to the reactivity-based
limits.’’ 3
Additional details about the
comparison of reactivity-based
reductions to VOC mass-based
reductions, the appropriateness of
CARB’s reactivity research to areas
outside of California, and the evaluation
of the effectiveness of CARB’s regulation
are provided in the Background section
below.
1 California Air Resources Board, ‘‘Initial
Statement of Reasons for the Proposed
Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from
Aerosol Coating Products,’’ Chapter VII, page 60,
May 5, 2000.
2 State of California Air Resources Board
Resolution 00–22, June 22, 2000, Agenda Item No.
00–6–1.
3 State of California Air Resources Board
Resolution 00–22, June 22, 2000, Agenda Item No.
00–6–1.
PO 00000
Frm 00004
Fmt 4701
Sfmt 4702
E:\FR\FM\07JAP2.SGM
07JAP2
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
Information normally found in a
Technical Support Document (TSD) is
incorporated into this proposed rule. A
separate TSD has not been written for
this proposed rulemaking.
C. Public Comment and Final Action
Because EPA believes the submitted
aerosol coatings regulation fulfills all
relevant requirements, we are proposing
to approve it into the California SIP as
authorized in section 110(k)(3) of the
CAA. We are also proposing to approve
the use of CARB’s Tables of MIR values
in California for the purpose of
implementation of the aerosol coatings
regulation. We intend to grant SIP credit
for the ozone equivalent VOC massbased reductions that are achieved by
CARB’s reactivity-based regulation.
Details on the methodology CARB used
to determine the equivalent VOC massbased tonnage reduction achieved by its
reactivity regulation is discussed in the
CARB staff report.4
Currently, EPA’s regulatory definition
of VOC (40 CFR 51.100(s)) excludes
certain compounds, such as methane
and ethane, which EPA has determined
to have negligible photochemical
reactivity with respect to the formation
of ozone. California’s reactivity-based
regulation, however, requires the
inclusion of the assigned MIR scale
reactivity value of each organic
compound present in the volatile
portion of a product, even if the
compound’s reactivity value is so low
that EPA has previously determined it
to be negligibly reactive and therefore
exempt.
In order to approve CARB’s aerosol
coatings rule, EPA proposes to modify
our regulatory definition of VOC so that
compounds previously excluded will
now be counted towards a product’s
reactivity-based VOC limit for the
limited purpose of CARB’s aerosol
coatings reactivity-based regulation.
Under 40 CFR 51.100(s), EPA has
excluded compounds from the
definition of VOC in recognition of the
fact that individual organic compounds
differ with respect to their incremental
contribution to ozone formation. EPA’s
exemption-based system separates
organic compounds into reactive and
negligibly reactive compounds. The
CARB’s reactivity-based regulation
makes this distinction unnecessary
because CARB’s rule assigns each
compound a reactivity factor that
accounts for its relative contribution to
4 California
Air Resources Board, ‘‘Initial
Statement of Reasons for the Proposed
Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from
Aerosol Coating Products,’’ Chapter II, page 37, May
5, 2000.
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
ozone formation. These previously
exempted compounds will continue to
be excluded from the Federal definition
of VOCs for other purposes.
We will accept comments from the
public on this proposed approval of the
CARB aerosol rule into the SIP and the
proposed modification of our definition
of VOC for the next 60 days. Unless we
receive convincing new information
during the comment period, we intend
to publish a final approval action that
will incorporate the regulations listed in
Table 1 into the federally enforceable
SIP and modify our definition of VOC
to support CARB’s aerosol coating rule.
The EPA, with CARB’s assistance,
intends to evaluate the performance of
this reactivity-based regulation in 3
years. This will allow time to compile
data on the implementation of, and
compliance with, the regulation, and
will allow time to conduct additional
technical analysis such as modeling
efforts needed to evaluate the effect of
the regulation on ambient ozone levels.
We encourage CARB to use this time to
collect data on the costs and
effectiveness of this regulation, both to
the regulated entities and to the
regulators. In particular, EPA is
interested in how implementation of
this regulation affects the development
of detailed emission inventories, as well
as industry compliance costs, including
recordkeeping and compliance testing,
manufacturing or material costs,
product quality and price. Towards this
goal, we are relying upon CARB’s Board
resolution 5 which ‘‘[d]irects the
Executive Officer to take the following
actions: (1) Monitor the progress of
manufacturers in meeting the reactivitybased VOC limits, (2) propose any
future regulatory modifications that may
be appropriate, and (3) continue to
evaluate emerging technologies for
aerosol coatings to determine if
additional ozone reductions will be
feasible in the future.’’
The proposed approval of CARB’s
aerosol coatings regulation based upon
VOC reactivity is limited to this source
category for this State. EPA believes that
relative reactivity-based regulations may
help provide the flexibility necessary to
achieve further emissions reductions
from some source categories to address
persistent ozone nonattainment
problems in areas of the country that
need further reductions in VOC
emissions to come into attainment with
federal ozone standards. EPA is
committed to continuing its support of
research on the suitability of relative
5 State of California Air Resources Board
Resolution 00–22, June 22, 2000, Agenda Item No.
00–6–1.
PO 00000
Frm 00005
Fmt 4701
Sfmt 4702
1643
reactivity-based regulations to other
geographic regions and to other source
categories through the national
Reactivity Research Working Group
(RRWG) of which CARB and EPA are
members.6 The purpose of the RRWG is
to encourage and sponsor research on
scientific questions concerning VOC
reactivity which may be of interest to
regulators. This group is affiliated with
NARSTO (formerly known as the North
American Research Strategy for
Tropospheric Ozone) and is a voluntary
organization currently composed of
industry, government and academic
representatives. The group has an open
membership and anyone may attend the
meetings and participate.
The EPA is specifically seeking public
comment on how reactivity-based
programs might affect industry
compliance and recordkeeping costs to
support effective implementation and
enforcement, and how industry and
regulatory agency costs and staff
requirements might change with respect
to emission inventories.
We are not seeking comments on the
reactivity limits or other specifics of
CARB’s rule; nor are we seeking
comments on EPA’s VOC exemption
process. The EPA has previously
published in 63 FR 48792 (September
11, 1998) its views on reactivity as it
relates to the regulation of VOC
emissions from consumer products
pursuant to CAA § 183(e) and this
proposal should not be construed as a
change in the Agency’s interpretation of
that provision. When commenting,
please indicate which section of this
proposal you are commenting on so we
can group similar comments together.
III. Background Information
A. Why Was This Regulation Submitted?
Ground level ozone, commonly
referred to as ‘‘smog,’’ is a serious air
pollutant that harms human health and
the environment. Ground level ozone is
a complex problem that is difficult to
control in part because ozone is not
emitted directly by specific sources. It
forms in the air when there are chemical
reactions between nitrogen oxides
(NOX) and VOCs in the presence of heat
and sunlight. Therefore, one way to
reduce ozone levels in many areas is to
control emissions of VOCs. Section
110(a) of the CAA requires States to
submit regulations that control VOC
emissions as part of the State’s SIP.
B. What Is Photochemical Reactivity?
There are thousands of individual
species of VOC chemicals that can
6 See ‘‘VOC Reactivity’’ at https://www.cgenv.com/
Narsto/.
E:\FR\FM\07JAP2.SGM
07JAP2
1644
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
combine with NOX and the energy from
sunlight to form ozone. The impact of a
given VOC on formation of ground-level
ozone is sometimes referred to as its
‘‘reactivity.’’ It is generally understood
that not all VOCs are equal in their
effects on ground-level ozone formation.
Some VOCs react extremely slowly and
changes in their emissions have limited
effects on ozone pollution episodes.
Some VOCs form ozone more quickly,
or they may form more ozone than other
VOCs. Others not only form ozone
themselves, but also enhance ozone
formation from other VOCs. By
distinguishing between more reactive
and less reactive VOCs, however, it
should be possible to decrease ozone
concentrations further or more
efficiently than by controlling all VOCs
equally.
Assigning a value to the reactivity of
a compound is not straightforward.
Reactivity is not simply a property of
the compound itself; it is a property of
both the compound and the
environment in which the compound is
found. The reactivity of a single
compound varies with VOW–NOX
ratios, meteorological conditions, the
mix of other VOCs in the atmosphere,
and the time interval of interest.
Designing an effective regulation that
takes account of these interactions is
difficult, and implementing and
enforcing such a regulation carries the
extra burden of characterizing and
tracking the full chemical composition
of VOC emissions.
1. History of EPA’s VOC Policy
Historically, EPA’s general approach
to regulation of VOC emissions has been
based upon control of total VOCs by
mass, without distinguishing between
individual species of VOC. EPA
considered the regulation of VOCs by
mass to be the most effective and
practical approach based upon the
scientific and technical information
available when EPA developed its VOC
control policy.
EPA issued the first version of its
VOC control policy in 1971, as part of
EPA’s SIP preparation guidance.7 In that
guidance, EPA emphasized the need to
reduce the total mass of VOC emissions,
but it also suggested that substitution of
one compound for another might be
useful when it would result in a clearly
evident decrease in reactivity and thus
tend to reduce photochemical oxidant
formation. This latter statement
encouraged States to promulgate SIPs
7 U.S. Environmental Protection Agency.
‘‘Requirements for Preparation, Adoption, and
Submittal of Implementation Plans.’’ Federal
Register, 36 FR 15486–15506 (1971).
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
with VOC emission substitution
provisions similar to the Los Angeles
County Air Pollution Control District’s
(LACAPCD) Rule 66,8 which allowed
some VOCs that were believed to have
low to moderate reactivity to be
exempted from control. The exempt
status of many of those VOCs was
questioned a few years later, when
research results indicated that, although
some of those compounds do not
produce much ozone close to the
source, they may produce significant
amounts of ozone after they are
transported downwind from urban
areas.9
In 1977, this research led EPA to issue
the second version of its VOC policy
under the title ‘‘Recommended Policy
on Control of Volatile Organic
Compounds,’’ (42 FR 35314, July 8,
1977) offering its own, more limited list
of exempt organic compounds. The
1977 policy identified four compounds
that have very low photochemical
reactivity and determined that their
contribution to ozone formation and
accumulation could be considered
negligible. The policy exempted these
‘‘negligibly reactive’’ compounds from
VOC emissions limitations in programs
designed to meet the ozone NAAQS.
Since 1977, the EPA has added other
compounds to the list of negligibly
reactive compounds based on new
information as it has been developed. In
1992, the EPA adopted a formal
regulatory definition of VOC for use in
SIPs, which explicitly excludes
compounds that have been identified as
negligibly reactive [40 CFR 51.100(s)].
To date, EPA has exempted 53
compounds or classes of compounds in
this manner.
In effect, EPA’s current VOC
exemption policy has resulted in a twobin system in which most compounds
are treated equally as VOCs and are
controlled and a separate smaller group
of compounds are treated as negligibly
reactive and are exempt from VOC
control.10 This approach was intended
8 County of Los Angles, Air Pollution Control
District (1972). Rules and Regulations. Rule 66
(1966). Amended November 2, 1972.
9 Dimitriades, B. ‘‘Oxidant/03 Air Quality
Benefits from Emission Substitution.’’ In:
‘‘Proceedings. Hydrocarbon Control Feasibility. Its
Impact on Air Quality’’ (and references herein).
Speciality Conference, Air Pollution Control
Association, April, 1977.
10 It should be noted that EPA has also taken VOC
reactivity into consideration in other ways, such as
the development of the consumer and commercial
product regulations under CAA § 183(e). EPA
considered VOC reactivity as a factor in developing
the federal consumer products program as directed
by the statute, and EPA’s approach was confirmed
by the courts. See, Allied Local & Regional Mfrs.
Caucus v. EPA, 215 F.3d 61 (D.C. Cir. 2000), cert.
denied 532 U.S. 1018 (2001). The EPA plans to
PO 00000
Frm 00006
Fmt 4701
Sfmt 4702
to encourage the reduction of emissions
of all VOCs that participate in ozone
formation. From one perspective, it
appears that this approach has been
relatively successful. EPA estimates
that, between 1970 and 2003, VOC
emissions from man-made sources
nationwide have declined by 54
percent. This decline in VOC emissions
has helped to decrease average ozone
concentration by 29 percent (based on 1hour averages) and 21 percent (based on
8-hour averages) between 1980 and
2003. These reductions have occurred
even though, between 1970 and 2003,
population, vehicle miles traveled, and
gross domestic product have risen 39
percent, 155 percent and 176 percent
respectively. [Latest Findings on
National Air Quality: 2002 Status and
Trends, EPA 454/K–03–001, August
2003; and The Ozone Report Measuring
Progress through 2003, EPA 454/K–04–
001, April 2004; Environmental
Protection Agency, Office of Air Quality
Planning and Standards, Research
Triangle Park, North Carolina]
On the other hand, some have argued
that a reactivity-based approach for
reducing VOC emissions would be more
effective than the current mass-based
approach. One group of researchers
conducted a detailed modeling study of
the Los Angeles area and concluded
that, compared to the current approach,
a reactivity-based approach could
achieve the same reductions in ozone
concentrations at significantly less
cost—or for a given cost, could achieve
a significantly greater reduction in
ozone concentrations.11 EPA recognizes
that, in theory, a well designed
reactivity-based program, in which each
individual VOC is regulated more or
less stringently based on its actual
contribution to ozone formation, would
be more efficient than the current
approach. On the other hand, there are
significant practical difficulties
involved in designing, implementing,
and enforcing such a program. We
believe that the CARB program we are
proposing to approve today will help
EPA and other States to evaluate
whether the benefits of a reactivitybased approach are sufficient to
outweigh these practical difficulties.
We also recognize that, in spite of the
progress that most parts of the country
develop its own regulation for aerosol coating
products under CAA § 183(e). Our future regulation
may differ from CARB’s regulation. If this turns out
to be the case, a process will need to be developed
to verify that the State’s requirements and limits are
at least as stringent as those in the national
standard.
11 A. Russell, J. Milford, M. S. Bergin, S. McBride,
L. McNair, Y. Yang, W. R. Stockwell, B. Croes,
‘‘Urban Ozone Control and Atmospheric Reactivity
of Organic Gases,’’ Science, 269: 491–495, (1995).
E:\FR\FM\07JAP2.SGM
07JAP2
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
have made in reducing ozone
concentrations, further reductions in
VOC emissions will likely be needed to
bring a number of areas into attainment
with the 8-hour ozone standard. In
particular, in areas where significant
VOC emission controls are already in
place, further mass-based emission
reductions may be difficult or very
expensive to achieve. In such situations,
regulations that distinguish between
individual VOCs and create an incentive
to shift production and use from more
reactive VOCs to less reactive VOCs may
provide the flexibility necessary to
continue progress towards attainment of
the ozone NAAQS.
2. History of CARB’s Reactivity Work
Regulatory authorities in California
have been experimenting with the
concept of reactivity-based regulations
for some time. The first regulation in
California that took reactivity into
account was Rule 66,12 adopted in the
mid 1960s by LACAPCD. This rule
restricted emissions of certain classes of
compounds which were defined by the
rule as photochemically reactive based
on their chemical structure (e.g.,
compounds having olefinic type of
unsaturation) to 40 pounds per day, but
allowed up to 3000 pounds per day
emissions for many other organic
compounds which were not defined by
the rule as photochemically reactive. In
other words, Rule 66 sought to regulate
certain VOCs more than others, based
on the assumption that some VOCs
participate more in ozone formation.
Rule 66 was very influential at the time
and versions of it were adopted by
several other States. However, the VOC
control approach taken by Rule 66 has
been superseded by EPA’s definition of
VOC (57 FR 3941, February 3, 1992),
which was based on the 1977 EPA
policy statement and which only
exempted a smaller number of
negligibly reactive compounds.
Like EPA’s 1977 policy, Rule 66 was
really a ‘‘two bin’’ system which tightly
controlled certain compounds, which
were defined as more photochemically
reactive, and applied a much lesser
level of control to a large class of
compounds, which were regarded as
less reactive. The main difference
between Rule 66 and the later EPA VOC
definition approach was the criteria for
classifying compounds as exempt (or
subject to lesser control), with the EPA
definition allowing a much smaller
group of compounds to be considered
non-reactive or exempt.
12 The South Coast Air Quality Management
District (SCAQMD), the successor agency to
LACAPCD, renamed this Rule 442.
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
In 1991 California adopted regulations
intended to differentiate between
species of VOC based upon a reactivity
scale, instead of a two bin system. The
1991 rules were the Low-Emission
Vehicles and Clean Fuels regulations
that CARB intended to reduce VOC
emissions by mass from motor vehicles
generally, but which also took into
account VOC reactivity differences in
organic gas when comparing the
emissions from alternatively fueled
vehicles (AFVs).13 14 Although not a
full-blown attempt to regulate VOCs by
their relative reactivity, CARB
nonetheless began the exploration of the
MIR scale as a mechanism to distinguish
between VOCs and encourage reduction
of more reactive VOCs.
Today’s proposal addresses CARB’s
most recent effort to utilize the concept
of VOC relative reactivity and the MIR
scale to regulate VOC emissions. This
rule reflects a major shift from the
traditional mass-based control strategies
for reduction of VOC emissions and
introduces this concept in a far more
significant way than in CARB’s previous
actions. In connection with the SIP
submittal for this aerosol coatings rule,
CARB has provided additional
supporting information in the form of
journal articles and reports which
describe VOC reactivity research efforts.
1645
Much of the work on reactivity scales
that CARB used as a basis for its aerosol
coatings rule was done at the University
of California at Riverside by William P.
L. Carter. Carter investigated 18
different ozone reactivity scales.15 All of
these scales are based on chamber
studies intended to evaluate the impact
of a given VOC on ozone formation
under certain assumed conditions. The
three most prominent scales he
developed were:
i. Maximum Incremental Reactivity
(MIR) scale—an ozone yield scale
derived by adjusting the NOX emissions
in a base case to yield the highest
incremental reactivity of the base
reactive organic gas mixture.16
ii. Maximum Ozone Incremental
Reactivity (MOIR) scale—an ozone yield
scale derived by adjusting the NOX
emission in a base case to yield the
highest peak ozone concentration.
iii. Equal Benefit Incremental
Reactivity (EBIR) scale—an ozone yield
scale derived by adjusting the NOX
emissions in a base case scenario so
VOC and NOX reductions are equally
effective in reducing ozone.
In addition to Carter’s work, there
have been other attempts to create
reactivity scales. One such effort is the
work of R. G. Derwent and M. E.
Jenkins, who have published articles on
a scale called the photochemical ozone
creation potential (POCP) scale.17 This
scale was derived for the conditions
prevalent in Europe. The POCP scale is
roughly consistent with those of Carter
although, as expected, there are some
differences because the POCP scale is
based on European conditions.
The CARB has relied most heavily on
Carter’s research for its regulatory
development and CARB has used the
MIR scale for development of the
aerosol coating regulation.18 The MIR
scale is designed using certain
assumptions about meteorological and
environmental conditions where ozone
production is most sensitive to changes
in hydrocarbon emissions and,
therefore, is intended to represent
conditions where VOC emission
controls will be most effective. The MIR
scale is expressed as grams of ozone
formed per gram of organic compound
reacted. Each compound is assigned an
individual MIR value, which enables
the reactivities of different compounds
to be compared quantitatively.
Individual MIR values now exist for
many commonly used compounds, and
a list of these individual values
comprises a scale.
To evaluate reactivity scales and
ensure that VOC reactivity is used
appropriately in its proposals, CARB
created the Reactivity Scientific
Advisory Committee (RSAC), a group of
leading researchers in the field of
atmospheric science. This group
reviews CARB’s reactivity related work
13 California Air Resources Board ‘‘Proposed
Regulations for Low-Emission Vehicles and Clean
Fuels-Staff report and Technical Support
Document,’’ State of California, Air Resources
Board, Sacramento, CA, August 13, 1990.
14 California Air Resources Board ‘‘Proposed
Regulations for Low-Emission Vehicles and Clean
Fuels-Final Statement of Reasons,’’ State of
California, Air Resources Board, July, 1991.
15 Carter, William P. L., ‘‘Development of Ozone
Reactivity Scales for Volatile Organic Compounds,’’
J. Air & Waste Manage. Assoc., 44: 881–899, (1994).
16 The CARB’s reactivity regulation defines the
term Reactive Organic Compound (ROC) as any
compound that has the potential, once emitted to
contribute to ozone formation in the troposphere.
ROCs include compounds which are excluded from
EPA’s definition of VOCs as found in 40 CFR
51.100(s).
17 See, for example, R. G. Derwent and M.E.
Jenkin, ‘‘Hydrocarbons and the Long-Range
Transport of Ozone and PAN Across Europe,’’
Atmospheric Environment, 25A, No. 8, 1661–1678,
(1991).
18 California Air Resources Board, ‘‘Initial
Statement of Reasons for the Proposed
Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from
Aerosol Coating Products,’’ Chapter II, page 12, May
5, 2000.
3. What Research Has Been Conducted
in Reactivity?
PO 00000
Frm 00007
Fmt 4701
Sfmt 4702
E:\FR\FM\07JAP2.SGM
07JAP2
1646
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
and convenes periodically in meetings
which are open to the public to
comment on CARB’s work.
The EPA has been closely following
the scientific literature on reactivity
scales, and is interested in how such
reactivity scales might be applied to
national programs or programs in other
States. Because reactivity depends on
the characteristics of the environment as
well as the compound, scales are
developed to represent a particular set
of environmental conditions in certain
geographic locations. It is not clear
whether a single scale can represent
actual ozone formation over the whole
country where meteorological and
environmental conditions vary
considerably. Many scales, including
the MIR scale are derived for ozone
formed during one day of reaction time.
The EPA is interested in whether such
scales adequately represent the ozone
formation from VOCs during multi-day
stagnation events or long-range
transport of pollutants, in such places as
those seen in the Northeast section of
the country, which may take place over
several days.
To help answer such questions, EPA
and CARB are participating in the
RRWG, which sponsored three
atmospheric photochemical modeling
studies to examine how changing the
reactivity of the mix of VOC emissions
might affect ozone formation across
wide geographical areas over time. The
three areas that researchers studied were
the Houston area, North Carolina, and
the eastern half of the United States.
The EPA anticipates that these three
studies and follow-up efforts will help
to answer many questions about the
potential use of relative reactivity in
developing, implementing, and
enforcing VOC regulatory programs.
C. Why Is Use of the Relative Reactivity
Concept Appropriate in California’s
Aerosol Coatings Rule?
There are five classes of
nonattainment for the 1-hour ozone
standard, ranging from marginal to
extreme. The Los Angeles—South Coast
Air Basin Area and the San Joaquin
Valley—San Joaquin Valley Air Basin in
California are currently the only areas in
the nation in the worst category of
extreme nonattainment (40 CFR 81.305
and 69 FR 20550). Under the 8-hour
standard, there are no areas classified
under the ‘‘extreme’’ ozone nonattainment category. South Coast is
classified as severe non-attainment and
San Joaquin is classified as serious nonattainment under the 8-hour standard.
Because of the elevated ozone levels in
Los Angeles, the San Joaquin Valley and
elsewhere in California, CARB has
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
adopted many innovative rules and
regulations to help reduce ozone
precursor emissions. These efforts
include adopting regulations which go
beyond current federally-mandated VOC
reduction requirements, such as
regulating a wider variety of area and
mobile sources and establishing
aggressive emission standards that force
development of new low-emission
technologies.
As one such effort, CARB already
adopted a statewide regulation in 1995
limiting the VOC mass content of 35
categories of aerosol coatings. This
regulation contained two tiers of VOC
limits and a provision to extend the
compliance deadline for up to 5 years
for each aerosol coating category if it
was determined that the limits were not
feasible. On November 19, 1998, CARB
amended the regulation to relax the
limits for 12 coating categories after
determining that the original limits were
not feasible even with the 5-year
extension. CARB made limits for 11
other categories more stringent. The
CARB also extended the compliance
date to January 1, 2002, for all 35
product categories covered by the
aerosol coating rule to provide time for
manufacturers to comply with the new
limits.
In the current SIP submittal, CARB
has determined that even with the
extended compliance date, some of the
VOC content limits remain
technologically challenging. In order to
preserve the air quality benefits of its
1998 rule, while at the same time
allowing manufacturers greater
flexibility in reformulating their
products, CARB is replacing its preexisting mass-based VOC limits for
aerosol spray coatings with reactivitybased limits that are designed to achieve
equivalent air quality benefits. The
CARB’s explicit goal was to develop
reactivity-based limits that would
ensure that the ozone reduction
commitment from its second tier massbased VOC limits would not be
compromised.19 For the reasons set
forth below, EPA believes that CARB’s
amended aerosol spray coating
regulation achieves this goal.
1. Equivalency of Air Quality Benefits
i. Sufficient information about the
source category. In order to determine
equivalent ozone reductions and set
appropriate limits, CARB collected
detailed product speciation information
19 California Air Resources Board, ‘‘Initial
Statement of Reasons for the Proposed
Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from
Aerosol Coating Products,’’ Executive Summary,
page 2, May 5, 2000.
PO 00000
Frm 00008
Fmt 4701
Sfmt 4702
and sales data from manufacturers. For
the aerosol coatings category, CARB
found that over 80 percent of the species
of VOCs typically used as ingredients
were well-studied and an additional 17
percent of the species typically used
would need only minor adjustment for
uncertainty in their MIR values. In other
words, CARB concluded that the
reactivity values of over 95 percent of
the VOCs generally used in the specific
category of aerosol coatings were fairly
well-studied and understood.20 The
accuracy and completeness of the VOC
inventory, and the availability of
scientifically reviewed and published
reactivity values for those VOCs used in
aerosol coatings may not be available for
other consumer product categories. The
CARB’s reactivity regulation defines the
term ‘‘reactive organic compound’’, or
‘‘ROCs,’’ as any compound that has the
potential, once emitted, to contribute to
ozone formation in the troposphere. The
ROCs include compounds which EPA
has excluded from the regulatory
definition of VOCs found in 40 CFR
51.100(s). To minimize confusion to the
reader, we will continue to use the term
‘‘VOC’’ in the remainder of this
proposal, instead of ‘‘ROC.’’ When the
term ‘‘VOC’’ is used in the context of
CARB’s reactivity-based aerosol coatings
rule, the reader should remember that
this refers to all VOCs, including those
compounds that are excluded from
EPA’s regulatory definition of VOC. The
accurate identification and
measurement of individual VOC
compounds and development of
accurate MIR values is crucial to the
effectiveness of a reactivity program.21
ii. Sufficient information about the
reactivity scale and its applicability to
California. In conjunction with this SIP
submittal, CARB provided a listing of
approximately 50 research articles to
help support its conclusion that this
aerosol coatings regulation based upon
VOC relative reactivity is appropriate
for conditions in California and that the
MIR scale chosen by CARB is the most
appropriate scale for this regulation.
As stated earlier, CARB relies on the
work of Carter in the development of the
scale for the aerosol coatings rule. Carter
investigated 18 different ozone
reactivity scales and concluded ‘‘[t]hat
the MIR scale (or a scale similar to it,
20 California Air Resources Board, ‘‘Initial
Statement of Reasons for the Proposed
Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from
Aerosol Coating Products,’’ Chapter IV, page 36,
May 5, 2000.
21 B.J. Finlayson-Pitts, J.N. Pitts Jr, ‘‘Atmospheric
Chemistry of Tropospheric Ozone Formation:
Scientific and Regulatory Implications,’’ J. Air
Waste Manage. Assoc. 43:1091–1100, (1993).
E:\FR\FM\07JAP2.SGM
07JAP2
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
such as one based on integrated ozone
over the standard) is appropriate for
regulatory applications where a
reactivity scale is required.’’ 22 He
determined that, while different
reactivity scales might give different
reactivity orderings of VOCs, for most
VOC species the general rankings among
the different scales were very similar.
He also found that even relatively large
variations in the base ROG mixture 23
had, in most cases, only a small effect
on relative reactivity. For example, a
two-fold increase in the amount of
aromatics in the base mixture of VOCs
in the chamber study resulted in less
than a 20 percent change in the relative
MIR reactivity. From this it could be
inferred that significant changes in the
ambient mixture of VOCs in the
atmosphere would not significantly
change the relative MIR value.
The various studies conducted to date
show good agreement in reactivity
values for most VOC species between
normalized reactivity scales generated
by airshed models and Carter’s boxmodeled calculations. For example,
Bergin et al.,24 summarized a number of
papers comparing reactivity scales
predicted by airshed models to those
predicted by Carter using a box-model.
Most of the papers are based on
simulations conducted with the
Carnegie Mellon/California Institute of
Technology model (CIT) for Los Angeles
using the ozone episode of August 27–
29, 1987. Bergin reports that airshed
model-derived spatially weighted
results behave similarly to MIRs.25 The
report further states that the greatest
differences were found for
formaldehyde and other compounds
whose reactivities were highly
dependent on photolytic reactions, and
in general, airshed model results for Los
Angeles agree well with MIRs, and
further show that individual organics
22 W.P.L. Carter, ‘‘Development of Ozone
Reactivity Scales for Volatile Organic Compounds,’’
J. Air Waste Manage. Assoc. 44:881–899, (1994).
23 From Carter’s article on ‘‘Development of
Ozone Reactivity Scales for Volatile Organic
Compounds,’’ the term ‘‘base ROG mixture’’ means
the mixture of Reactive Organic Gases (ROGs)
initially present or emitted in the Empirical Kinetic
Modeling Approach (EKMA) scenarios except for
biogenic VOCs, VOCs present aloft, or VOCs added
for the purpose of calculating their incremental
reactivities.
24 M. Bergin, W.P.L. Carter, J. Milford, P.J.
Ostrowski, A.G. Russell, Reactivity Assessments,
Reactivity Research Working Group (May 5, 1999).
(ftp://ftp.cgenv.com/pub/downloads/RRWGdoc/
assess-2.pdf).
25 M. Bergin, W.P.L. Carter, J. Milford, P.J.
Ostrowski, A.G. Russell, Reactivity Assessments,
Reactivity Research Working Group, Page 12, (May
5, 1999). (ftp://ftp.cgenv.com/pub/downloads/
RRWGdoc/assess-2.pdf).
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
have very different ozone formation
impacts.
While Bergin’s reactivity assessment
indicates a general support for the
concept of relative reactivity, she also
points out that gaps exist in the current
knowledge base of the scientific
community and points to areas where
further investigation is needed. For
example, Bergin acknowledges that
although airshed model results for Los
Angeles agree well with MIRs, such a
study has not been conducted for other
regions. Also, Bergin suggested that
additional work is needed to examine
the effects of aromatics under several
different conditions, and that Eastern
transport conditions should also be
examined in a multi-day scenario. The
RRWG is currently reviewing studies
which examine the reactivities in the
eastern half of the United States which
will help to answer some of these
questions.
Similarly, recent work by Martien and
Harley found that ‘‘[f]or most species
studied’’ * * * ‘‘[r]eactivity scales
developed by 3-D modeling resulted in
similar rankings of individual VOC
when compared to reactivity scales
developed by Carter using a box
model.’’ 26 They also point out that
‘‘[S]ite-to-site differences (in reactivity
values) can be large when absolute
reactivity scales are considered. The
variation in reactivity across sites is
reduced when reactivity is measured on
a relative rather than absolute scale.
Differences in relative reactivity may
still occur as a function of location, with
differences likely to be magnified where
absolute reactivities are low.’’
One study submitted by CARB to EPA
attempts to address the issue of whether
the MIR scale adequately represents
VOC reactivity in transport scenarios.
Kaduwela and his associates 27 assessed
for the first time whether box-model
based scales are applicable to regionalscale domains, which include transport
of pollutants through urban and rural
areas. They did this by conducting gridbased photochemical simulations in a
regional domain in central California for
five compounds and found a linear
correlation between box-model based
scales and regional grid-based scales.
These studies indicate a correlation
between box-model scales used in
26 P. Martien, R.Harley, ‘‘Development of
Reactivity Scales via 3-D Grid Modeling of
California Ozone Episodes,’’ Final report prepared
for California Air Resources Board, May 2002.
27 A. Kaduwela, V. Hughes, L. Woodlouse, P.
Allen, J. DaMassa, A. Ranzieri, ‘‘Photochemical
Reactivity of Organic Compounds in Central
California: A Grid-Based Modeling Study,’’
Presented at Stanford University, CA July 26–28,
1999.
PO 00000
Frm 00009
Fmt 4701
Sfmt 4702
1647
Carter’s work and the more detailed
scales. Therefore, CARB concludes that
the box-model’s lack of physical detail
and shorter episode time does not limit
the suitability of the MIR values with
respect to concerns about transport
within California.
During an October 1999 RSAC
meeting, a member of the public asked
the RSAC whether the scenarios used to
calculate MIRs are realistic. The RSAC
committee ‘‘[r]esponded that the relative
reactivity doesn’t change between
scenarios and that, in a study which
examined an exposure metric calculated
by a 3-D model, the relative reactivities
correlated well with MIRs.’’ 28 At the
same meeting, a member of the public
also asked the RSAC if MIR conditions
were appropriate for California. The
committee’s response was that whether
MIR conditions were appropriate for
California was a policy decision. The
CARB’s SIP submittal states 29 that
‘‘[w]hile the MIR scale has been
extensively tested as appropriate for use
in California, we caution that our
research has focused on California
atmospheric conditions only. As such,
the suitability of using the MIR scale for
regulatory purposes in other parts of the
United States has not been
demonstrated, and may not be
appropriate.’’
iii. Approach to Uncertainty.
Although the MIR values are calculated
with what a peer reviewed report 30
describes as a ‘‘state-of-the-science’’
chemical mechanism, the reactivity
values of some VOCs are still
uncertain,31 while those of other VOCs
have been more thoroughly studied and
will not likely change with further
research. To account for this
uncertainty, CARB has applied Carter’s
uncertainty ranking which defines 6
categories or ‘‘bins’’ to describe the
‘‘certainty’’ of the chemical mechanism
used to determine the MIR values. The
uncertainty scale is subjective, but it is
described as Carter’s best judgment of
the certainty scientists currently have of
an organic compound’s chemical
28 Minutes of the Reactivity Scientific Advisory
Committee, October 8, 1999, https://www.arb.ca.gov/
research/reactivity/rsac/oct99-min.html.
29 State Implementation Plan (SIP) Submittal
letter from Michael Kenny (CARB) to Wayne Nastri
(US EPA, Region IX), March 13, 2002.
30 W.R. Stockwell, ‘‘Review of the Updated
Maximum Incremental Reactivity Scale of Dr.
William Carter,’’ Prepared for the California Air
Resources Board, Page 151, November 29, 1999—A
copy can be found in section 4N of CARB’s SIP
submittal for this rule.
31 California Air Resources Board, ‘‘Initial
Statement of Reasons for the Proposed
Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from
Aerosol Coating Products,’’ Chapter II, Page 13, May
5, 2000.
E:\FR\FM\07JAP2.SGM
07JAP2
1648
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
reaction mechanism and its effect on
that compound’s estimated MIR value 32.
If the MIR value of a compound is
relatively certain or if there are some
uncertainties but the MIR value is not
expected to change significantly, the
compound is assigned to bin one. If the
current mechanism is probably incorrect
and biases in atmospheric reactivity
predictions are uncertain, the
compound is assigned to bin six. When
calculating an equivalent ozone
reduction, CARB identifies which of the
6 bins a compound is in, and then
multiplies the compound’s MIR value
with a factor of between 1 and 2 to
compensate for the uncertainty of that
MIR value. The uncertainty factors
associated with each bin were
developed by CARB with input from
Carter. The CARB applies an
uncertainty factor of 1.0 to compounds
classified within uncertainty bins one
and two; a factor of 1.25 to compounds
in bin three; a factor of 1.5 to
compounds in bin four; and a factor of
2.0 for compounds in bins five and six.
For certain hydrocarbon solvents
defined under the regulation, CARB
uses an uncertainty factor of 1.15. The
CARB also developed a methodology for
those compounds used in aerosol
coatings that did not have published
MIR values. The methodology, which
was reviewed by the RSAC, provides an
estimate for the presumed upper limit
MIR value. No adjustment factor is
applied to the upper limit MIRs as the
method infers the highest reactivity of
the chemical.33
Other researcher 34 35 36 looking into
the aspects of uncertainties in chemical
reaction rate parameters, used in the
model to calculate MIRs, believe that
the uncertainties in the chemical rate
parameters have directionally similar
32 W.R. Stockwell, ‘‘Review of the Updated
Maximum Incremental Reactivity Scale of Dr.
William Carter,’’ Prepared for the California Air
Resources Board, Page 122, November 29, 1999—A
copy can be found in section 4N of CARB’s SIP
submittal for this rule.
33 California Air Resources Board, ‘‘Initial
Statement of Reasons for the Proposed
Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from
Aerosol Coating Products,’’ Chapter IV, pages 32–
37, May 5, 2000.
34 Y. Yang, W.R. Stockwell, J.B. Milford,
‘‘Uncertainties in Incremental Reactivities of
Volatile Organic Compounds,’’ Environ. Sci.
Technol., 29, 1336–1345, (1995).
35 M.S. Bergin, A.G. Russell, J.B. Milford, ‘‘Effects
of Chemical Mechanism Uncertainties on the
Reactivity Quantification of Volatile Organic
Compounds Using a Three-Dimensional Air Quality
Model,’’ Environ. Sci. Technol., 32, 694–703,
(1998).
36 N.L. Kelly, T.Y. Chang, ‘‘An experimental
Investigation of Incremental Reactivities of Volatile
Organic Compounds,’’ Atmospheric Environment,
33, 2101–2110, (1999).
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
effects on the reactivities of most
compounds. That is, if compound ‘‘a’’
had a higher reactivity value than
compound ‘‘b,’’ then after taking into
account the uncertainties in their
chemical rate parameters, compound
‘‘a’’ would generally still have a higher
reactivity value than compound ‘‘b.’’
These researchers conclude that the
significance of these uncertainties could
be minimized by using reactivities in a
relative sense, as CARB has done in this
rule.
iv. Do Federal VOC exemptions apply
to CARB’s program?
Because CARB’s regulation attempts
to account for the actual contribution to
ozone formation by each organic
compound, it does not exempt any
reactive compounds, including those
that EPA has exempted from the
definition of VOC pursuant to 40 CFR
51.100(s). In order to get a more accurate
calculation of a product’s impact on
ozone formation, CARB uses the
assigned reactivity value of each
compound, however high or low its MIR
value. Therefore, compounds such as
acetone, which are excluded from EPA’s
definition of VOCs in 40 CFR 51.100(s),
are counted towards the compliance
limit under CARB’s reactivity-based
regulation.
v. No backsliding. In developing the
proposed reactivity limits, one of
CARB’s goals was to ensure that the
ozone reduction commitment from the
existing mass-based VOC limits for
aerosol spray coatings would not be
compromised. In certain situations,
however, a reactivity-based regulation
could result in increased ozone
concentrations over a traditional VOC
mass-based regulation. For instance,
because the MIR scale is based on a 1day simulation, during a multi-day
episode, a manufacturer could
substitute the proper amount or too
much of a lower reacting compound for
a higher reacting one and thereby
increase ozone formation over longer
periods of time.
While we believe there are
circumstances under which ozone
formation could potentially increase
because of use of reactivity-based VOC
limits, we also recognize that the same
unintended consequences can occur
with current mass-based VOC rules. The
CARB reported 37 that one company
intended to comply with stricter CARB
VOC mass-based limits by using less
total VOC, but also by increasing the
amount of much more reactive VOCs to
compensate for solvency needs in the
37 California Air Resources Board letter from
Michael Kenny to Deborah Jordan, U.S. EPA,
Region IX, dated July 24, 2000.
PO 00000
Frm 00010
Fmt 4701
Sfmt 4702
product. The CARB also reported that
another large company indicated that its
compliance strategy with more stringent
VOC mass limits would be to increase
the aromatic content (increasing
reactivity) in its products. In these
instances, CARB points out that the
increased reactivity of the VOC
emissions likely reduces the benefits of
the lower mass of VOC emissions. There
is no evidence to suggest, however, that
regulated entities will always choose to
use smaller amounts of higher reactivity
compounds in place of lower reactivity
compounds when a product’s massbased VOC limit is reduced. In any
event, it is impossible to predict
whether the use of smaller amounts of
more reactive VOCs will result in more
ozone without knowing how the
identity and proportions of the other
VOC ingredients in the product will
change. While we acknowledge that
there is the potential for this unintended
consequence of mass-based controls, we
generally believe that achieving
significant mass reductions of VOCs is
directionally correct in most situations.
As noted above, however, EPA believes
that reactivity-based approaches such as
the one developed by CARB may be a
promising alternative to mass-based
approaches in some cases where
additional VOC controls are necessary.
Revisions to the SIP should contribute
to progress towards reaching attainment
with the NAAQS and not relax emission
standards or retreat from emission
reduction goals already achieved.
Towards these goals, CARB has assured
EPA that there will be no backsliding as
a result of the use of the relative
reactivity approach. With assistance
from CARB, EPA intends to monitor the
effectiveness of the aerosol coatings rule
to ensure that the rule obtains the
intended and required reductions in
ambient ozone levels.
2. Evaluation and Revision
The development, maintenance,
evaluation, and revision of a reactivitybased VOC regulation requires
significant resources and technical
expertise. The CARB’s commitment to
the reactivity concept is evidenced by
funding, between 1989 to the present,
over $4,000,000 worth of research on
reactivity related projects including
modeling, chemical mechanism
development, atmospheric chemistry
and VOC speciation.
Similarly, we believe that additional
resources and technical expertise are
needed to implement and enforce a
reactivity-based regulation than for a
traditional mass-based regulation. For
example, under a mass-based VOC
regulation, analysis of a coating to
E:\FR\FM\07JAP2.SGM
07JAP2
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
determine compliance largely requires
simply determining the weight
difference of a sample before and after
heating it in an oven 38. This testing is
relatively easy and inexpensive, thereby
facilitating enforcement by the
regulating authority or others.
In contrast, determining compliance
of the same product with a reactivitybased regulation is more complex and
consequently more expensive. Here, the
laboratory needs to identify and
quantify each individual VOC present in
the sample, possibly with multiple gas
chromatography with mass
spectrometry (GC/MS) runs. In order to
determine compliance, the regulatory
agency then must multiply the
concentration of each compound in the
aerosol coating by its MIR value and
then sum the results to determine the
product’s total MIR value. In some
cases, the MIR values for isomers of
compounds are different, such as for
ortho, meta and para xylenes (MIR =
7.49, 10.61, and 4.25 respectively).
Speciation of isomers increases the
complexity of the analysis. In addition,
the identification of hydrocarbon
solvents by boiling point range and
aromatic content will add an additional
step to the analysis. The CARB
laboratory staff routinely uses GC/MS
techniques to analyze products for a
relatively small number of compounds
excluded from EPA’s regulatory
definition of VOC which may be in
consumer products, so CARB has some
experience with these analytical
techniques. Further, CARB is ‘‘[f]ully
prepared to vigorously enforce this
regulation’’ and their ‘‘[e]nforcement
inspectors and laboratory staff have
expertise and resources to collect and
test aerosol coating products to verify
compliance with the regulation.’’ 39
Because any complex regulation can
potentially multiply the opportunities
for non-compliance, whether intentional
or inadvertent, EPA believes that an
intensive program to monitor and
enforce compliance is a critical element
to any VOC reactivity-based regulation.
D. Are California’s Relative ReactivityBased Regulations Appropriate for
Areas Outside of California?
1. The CARB’s technical support for
this program in California does not
necessarily demonstrate that VOC
reactivity-based programs would be
appropriate or effective in other areas or
for other regulatory programs. The
CARB’s SIP submittal cautions that its
38 See
40 CFR 60, appendix A Reference Method
24.
39 State Implementation Plan submittal letter from
Michael Kenny (CARB) to Wayne Nastri (U.S. EPA,
Region IX), March 13, 2002.
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
research has focused only on California
atmospheric conditions and that the
suitability of the MIR scale for
regulatory purposes in other areas has
not been demonstrated. The CARB
further states 40 that VOC relative
‘‘[r]eactivity needs to be examined for
the rest of the country.’’ and that they
‘‘[s]upport these investigations and plan
to continue CARB’s participation in the
RRWG.’’
EPA is aware that only recently has
there been published, coordinated
scientific research to attempt to address
questions concerning the use of VOC
reactivity-based regulations in other
locations. For example, a recent
NARSTO report describes limitations to
ozone control using a VOC reactivitybased approach. The NARSTO report
suggested that the approach might only
be effective when the ambient
conditions are ‘‘[V]OC limited and
where natural hydrocarbon emissions
are not dominant.’’ 41 In addition, the
NARSTO report states that ‘‘[t]he
reactivity of specific VOCs can change
from locale to locale, and thus the
specifics of the approach must be
regionally tailored.’’ As noted earlier,
the RRWG has sponsored a series of
recent studies exploring these issues.
One of the concerns with the
representativeness of MIR values is that
they are based on a model which
simulates reactions over a single day
and may not account for slower reacting
compounds which might continue to
form ozone over several days. These
slower reactions could result in more
ozone formation than is predicted by the
MIR scale in areas experiencing multiday stagnation events or increased
ozone formation in downwind areas due
to pollutant transport.
The MIR scale is basically a reducedform model, or a model of a model,
which attempts to characterize in a
single number the relative contribution
of individual compounds to the
formation and accumulation of ozone in
a complex atmospheric system. Thus, a
particular chemical mechanism and set
of assumed environmental conditions
are implicit in the MIR scale. The
purpose of comparing the MIR scale to
reactivities calculated using an airshed
model is to evaluate whether the MIR
scale, as a reduced-form model,
adequately represents the behavior of
the more complex airshed model, which
takes into account spatially and
temporally varying meteorology and
40 State Implementation Plan Submittal letter
from Michael Kenny (CARB) to Wayne Nastri (US
EPA Region IX), March 13, 2002.
41 The NARSTO, An Assessment of Tropospheric
Ozone Pollution—A North American Perspective,
page 3–19, July 2000.
PO 00000
Frm 00011
Fmt 4701
Sfmt 4702
1649
emissions. If comparisons show a
disagreement between the MIR values
and the airshed derived values, that may
suggest that it may not be appropriate to
try to capture the behavior of the system
in the single scale. If comparisons do
show an agreement, this would suggest
that the MIR scale can reproduce the
behavior of the complex system, at least
for the set of conditions considered.
Several researchers have performed
such comparisons, including Bergin,
Derwent and Stockwell. Bergin et al.,42
calculated reactivity values using a
more detailed three-dimensional
photochemical model and compared
their results against the values
calculated by the simpler model used to
develop CARB’s reactivity program for
their alternative fuels program. Bergin
found that results were well correlated
between Carter’s simpler model and
their more detailed model. However,
these researchers also found that
toluene, ethylbenzene, two xylene
species, and some aldehydes had lower
reactivity values predicted by the more
detailed model as compared to the
simpler model. Bergin concluded that
differences in the predicted reactivity
values were possibly due to multi-day
simulation periods and the inclusion of
cloud cover by the more detailed model.
Derwent 43 also reports that single-day
or multi-day conditions appear to be
important in establishing quantitative
reactivity scales for the less reactive
organic compounds. Stockwell,44 who
completed the peer review of Carter’s
reactivity mechanism, states that singleday scenarios are used to calculate
incremental reactivities by definition,
but even relatively unreactive organic
compounds may have a non-negligible
effect on ozone concentrations if
multiple-day scenarios are considered.
When he calculated incremental
reactivities for multiple-days for
polluted European conditions, he found
that ethane’s MIR value increased over
6 times from a MIR value of 0.19 on the
first day to 1.17 on the 6th day. He also
found that Dimethyoxymethane’s MIR
42 M.S. Bergin, A.G. Russell, J.B. Milford,
‘‘Quantification of Individual VOC Reactivities
Using a Chemically Detailed, Three-Dimensional
Photochemical Model,’’ Environ. Sci. Technol., 29,
3029–3037, (1995).
43 R.G. Derwent, M.E. Jenkin, S.M. Saunders, M.J.
Pilling, ‘‘Characterization of the Reactivities of
Volatile Organic Compounds Using a Master
Chemical Mechanism,’’ J. Air and Waste Manage.
Assoc., 51, 699–707, (2001).
44 W.R. Stockwell, H. Geiger, K.H. Becker,
‘‘Estimation of Incremental Reactivities for Multiple
Day Scenarios: An Application to Ethane and
Dimethyoxymethane,’’ Atmospheric Environment,
35, 929–939, (2001).
E:\FR\FM\07JAP2.SGM
07JAP2
1650
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
value increased as the length of the
simulation period increased.
While we are uncertain whether
results based on European conditions
might generally apply to conditions
found in California or the United States,
these studies raise two questions. First,
is the increase in MIR values during a
multi-day stagnation event mainly a
concern for slower reacting compounds
or a more widespread issue, and second,
should any changes be made to MIR
scale values to account for the apparent
increases in reactivity values in multiday stagnation scenarios. Additional
research may be needed in this area to
understand more fully the impacts of
multi-day scenarios on relative
reactivity values and the prevalence of
transport and multi-day stagnation
conditions on a regional scale within
California’s ozone nonattainment areas
and ozone nonattainment areas in other
parts of the country. While we have
some concerns about the greater level of
effort required to develop, implement,
and enforce reactivity-based programs,
we believe that California has the
resources and technical expertise
needed to develop and maintain a
complex program such as this one.
E. How Will the Effectiveness of This
Reactivity-Based Program Be Evaluated?
1. We plan to evaluate the
effectiveness of the aerosol coatings rule
in 3 years. Areas we may review include
changes in the composition and
quantity of VOC emissions, which
would require establishing a baseline of
current emissions.
2. We are also interested in evaluating
changes in ambient air quality that
result from the use of the relative
reactivity approach in this rule. We
recognize that currently available
computer models have limitations in
their ability to evaluate the actual
ambient effects of reducing emissions of
specific VOC species from a particular
product category. Also, while it is
possible to show an air quality benefit
of substituting individual VOCs with
lower reactivity for more reactive ones
using a three-dimensional
photochemical model, it is not clear that
current photochemical modeling
systems are adequate to predict the
impacts of the wide variety of
simultaneous substitutions that may
occur under an MIR-weighted regulatory
program. The EPA, with CARB’s
assistance, plans to investigate possible
modeling enhancements to evaluate the
effects of the aerosol coatings rule, and
hopes to identify modeling
‘‘experiments’’ to further test the MIR’s
predictive performance.
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
While a VOC reactivity-based
regulation may result in a more efficient
regulation in terms of more flexible
reformulation options for manufacturers
and an additional control strategy to
reduce tropospheric ozone, we are also
interested in how costs under a
reactivity-based regulation might change
for monitoring and recordkeeping.
Under a reactivity-based program,
emission inventory efforts may increase
for industry periodically to provide
fully speciated product information and
for regulatory agencies to input this
information into emission inventory
data bases. We are interested in the
public’s comment on how the industry’s
and regulatory agency’s costs and staff
requirements might change with respect
to emission inventories.
3. As stated earlier, CARB intends to
keep up to date on VOC reactivity
research through a review of the MIR
values every 18 months and a review of
the reactivity limits before January 1,
2007.
F. How Has CARB Addressed Concerns
About Air Toxics and Ozone-Depleting
Substances?
The CARB’s aerosol coatings
regulation prohibits the use of three
toxic air contaminants: Methylene
chloride, perchloroethylene and
trichloroethylene. While the regulation
does not ban the use of other
compounds listed as ‘‘hazardous air
pollutants’’ that are commonly used in
aerosol coatings such as xylene and
toluene, CARB believes that emissions
of these other toxic compounds are
likely to be reduced through the overall
emission limits imposed on the
individual product categories. Regulated
entities will have an incentive to use
less of compounds like toluene and
xylene because of their higher reactivity,
and this will outweigh the interest in
choosing VOCs based solely upon their
cost.
The CARB’s regulation also prohibits
the sale, supply, application, or
manufacture for use in California, of any
aerosol coating product which contains
a stratospheric ozone-depleting
substance. Existing product
formulations which contain an ozonedepleting substance that complies with
the reactivity limits and was sold in
California during 1997 or product
formulations containing an ozonedepleting substance that was sold in
California during 1997 that is
reformulated to meet the reactivity
limits, as long as the content of the
ozone-depleting substances in the
reformulated product does not increase,
are exempted from this provision.
PO 00000
Frm 00012
Fmt 4701
Sfmt 4702
G. What Changes in Enforcement
Strategies Will Likely Occur Due to This
Relative Reactivity-Based Regulation?
1. How will testing for compliance
change under CARB’s aerosol coatings
regulation? As discussed earlier, under
a traditional mass-based regulation,
analysis of a coating to determine
compliance is performed using EPA
Reference Method 24.45 This method
involves heating the sample in an oven
and determining the weight difference
of the sample before and after heating.
Additional analysis is needed to
account for the propellant and, if
present in the sample, compounds
which are excluded from EPA’s
definition of VOCs. Under a mass-based
rule, the laboratory does not need to
know which individual hydrocarbons
are present in order to perform Method
24, other than to identify if a limited
number of excluded compounds are
present in the coating. Manufacturers
are generally willing to reveal the
proportions of exempt substances
because that helps to demonstrate
compliance with the mass-based VOC
limits.
Determining compliance under a
reactivity-based regulation is more
complex, but still within the capabilities
of CARB’s laboratory. Specifically, the
regulator must perform expensive and
complex GC/MS analysis to identify and
quantify each VOC present in the
product in order to calculate the
product weighted MIR. To facilitate this
compliance determination, CARB’s
aerosol coatings rule allows CARB to
request manufacturers to provide a
listing of the VOCs and their
concentrations in each product so the
laboratory knows which VOCs to
analyze for and their target
concentrations. While laboratories could
perform the analysis without such a
listing, it would be substantially more
difficult, time-consuming, and
expensive. This increased difficulty in
assuring compliance is among the
reasons that EPA is concerned that
CARB allocate sufficient resources to
monitor and enforce the reactivity-based
limits.
2. How does a reactivity regulation
affect the availability of emissions data?
In the past, determining compliance
with emission limits under a massbased VOC rule such as CARB’s aerosol
coatings rule did not raise concerns
about confidential business information
(CBI) because one could determine
compliance with the product’s VOC
limit without ever having to know all of
the individual VOC ingredients present
45 See
40 CFR 60, appendix A, Reference Method
24.
E:\FR\FM\07JAP2.SGM
07JAP2
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
information gathered to confirm
compliance with CARB’s aerosol
coatings rule. Confidential information
such as survey data submitted by
companies under Section 94524 of
CARB’s aerosol coatings regulation to
CARB and EPA in support of any future
rule development efforts, will continue
to be handled in accordance with
applicable CBI regulations.
We believe that this compromise
between the competing objectives of
disclosure of emissions data and
protection of CBI provides a basis for
approving CARB’s innovative reactivitybased regulation into the SIP. We also
believe that the compromise is
consistent with the purpose of CAA
§ 114(c) and EPA’s regulations defining
emissions data.
in the product. However, under a
reactivity-based rule, one would need to
know the specific VOCs in a product
and their proportions (i.e., the product
formulation) in order to determine
compliance with its reactivity-based
VOC limit. Because this information is
an integral part of determining
compliance with the product’s
reactivity-based limit, the list of VOCs
would be considered ‘‘emissions data,’’
which must generally be available to the
public.46 However, industry may view
the release of such detailed VOC
information to the general public or to
their business competitors as a major
concern because of the potential for
release of trade secrets and propriety
CBI.
To help resolve these competing
issues, we note that aerosol coatings are
composed of a VOC portion and a
portion made up of various non-reactive
compounds such as resins and solids
which, based on CARB’s aerosol
coatings regulation, do not contribute to
ozone formation and are assigned an
MIR value of zero. Consistent with
section 114(c) of the CAA, and our
regulations concerning the release of
emissions data at 40 CFR § 2.301, we
believe the public’s right to emissions
data is satisfied by assuring access to the
portion of the data which comprises the
VOCs alone. Information on the nonreactive compounds, i.e., those that do
not contribute to ozone formation,
would not need to be released, thereby
preserving potential trade secrets.
The CARB and the aerosol coatings
industry held discussions and reached
an agreement that CARB VOC testing
results and company-supplied
formulation data required to be
submitted by Section 94526 of CARB’s
aerosol coatings regulation would be
made available to the public, upon
request, to allow others to verify
compliance with the reactivity-based
aerosol coating regulation. It was further
agreed that non-reactive compounds in
each product formulation would be
‘‘lumped’’ or aggregated to protect
confidentiality.47
Both CARB and EPA will retain their
authority to access all ingredient
information, including non-VOC
ingredients or information otherwise
claimed to be CBI, in order to determine
compliance with the regulation.
The availability to the public of VOC
ingredient information constituting
emissions data only applies to
1. What Does CARB’s Aerosol Coatings
Regulation Cover?
This section contains a very brief
summary of key portions of CARB’s
regulation. The reader should refer to
the actual regulation 48 for additional
details.
The regulation applies to aerosol
coatings, aerosol clear coatings and
aerosol stains. It applies to any person
who sells, supplies, offers for sale,
applies or manufactures for use in
California any aerosol coating subject to
the limits in the regulation. The
46 Emissions data is defined in 40 CFR
2.301(a)(2)(i).
47 The CARB letter from Michael Kenny to Jack
Broadbent, U.S. EPA, Region IX, dated May 16,
2002.
48 https://www.arb.ca.gov/consprod/regs/
aeropnt.pdf https://www.arb.ca.gov/consprod/regs/
Aeropnt.doc or California Code of Regulations, Title
17, Division 3, Chapter 1, Subchapter 8.5, Article
3.
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
IV. Summary of CARB’s Aerosol
Coatings Regulation
A. What Does CARB’s Regulation
Require?
The CARB has previously controlled
VOC emissions from aerosol coatings in
California by limiting the mass of VOCs
in the product, with limits expressed as
maximum allowable percent by mass of
VOC. CARB’s new approach relies on
the fact that individual VOCs may form
different amounts of ozone, or form
ozone more quickly, once they are
emitted into the air. The CARB is
implementing a regulation that would
limit ozone formation by taking into
account the relative reactivity of
different VOC ingredients.
The CARB’s aerosol coatings
regulation contains sections on
applicability, definitions, limits and
requirements, exemptions,
administrative requirements, variances,
test methods, Federal enforceability and
references tables of MIR values for
different compounds including
hydrocarbon solvents.
PO 00000
Frm 00013
Fmt 4701
Sfmt 4702
1651
regulation prohibits the commercial
application of non-complying aerosol
coating products.
The regulation does not apply to
aerosol lubricants, mold releases,
automotive underbody coatings,
electrical coatings, cleaners, belt
dressings, anti-static sprays, layout
fluids and removers, adhesives,
maskants, rust converters, dyes, inks,
and leather preservatives or cleaners.
The regulation also does not apply to
aerosol coating products manufactured
in California for shipment and use
outside of California.
Aerosol coating products
manufactured beginning June 1, 2002,
for general coating categories as defined
in the regulation and January 1, 2003,
for specialty coatings need to comply
with the reactivity-based VOC limits
specified in the regulation. Aerosol
products manufactured before the
effective dates must comply with the
existing mass-based VOC limits.
However, products labeled with the
applicable reactivity-based VOC limit,
must meet that limit. The regulation
contains a sell-through provision
whereby products manufactured prior to
the effective date can be sold, supplied,
offered for sale, or applied up to 3 years
after the effective date.
The regulation prohibits the use of the
toxic air contaminates methylene
chloride, trichloroethylene, and
perchloroethylene. It also prohibits the
use of stratospheric ozone-depleting
substances in aerosol coating products
except in limited situations allowed by
the regulation.
The regulation contains labeling and
reporting requirements, and provisions
for a regulated entity to request a
variance from the VOC reactivity limits
if the entity cannot comply due to
extraordinary reasons beyond
reasonable control. The test method
section specifies that CARB Method 310
is to be used to determine compliance
with the regulation. Alternative test
methods may be used which are shown
to identify and quantify accurately each
ingredient, after approval in writing by
the CARB Executive Officer. However,
as stated in the aerosol coatings
regulation,49 for purposes of Federal
enforceability, EPA is not bound by
approval determinations made by the
CARB Executive Officer for variances or
test methods. While EPA believes CARB
would not approve major test method
modifications that might compromise
the integrity of a test result, or grant a
variance request that would adversely
49 California Code of Regulations, Title 17,
Division 3, Chapter 1, Subchapter 8.5, Article 3,
§ 94528.
E:\FR\FM\07JAP2.SGM
07JAP2
1652
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
impact an approved attainment
demonstration, EPA can pursue separate
action to ensure that test results are
enforceable, accurate, and reproducible,
and that a variance does not adversely
impact attainment.
Variances and major modifications to
test methods must be submitted to EPA
and must be approved into the SIP
before they can be Federally
enforceable. For the purposes of Federal
enforceability, facilities operating under
a variance or modified test method
approved by the CARB Executive
Officer must continue to comply with
the original regulation until the variance
or major test method modification is
also approved by EPA into the SIP. The
EPA does not normally approve
Executive Officer discretion in
regulations submitted for SIP approval
as this would allow potentially
significant modifications to a regulation
or test method without subsequent
review and approval by EPA.
We are proposing to approve this
Executive Officer provision in this rule
because this is a new and innovative
program and, as such, may require a
temporary variance or an unanticipated
modification to the test method in the
short term, and the regulation states that
EPA is not bound by the decisions of the
Executive Officer. The EPA intends to
monitor CARB’s implementation of
these rule provisions and we will
review test method modifications and
variance requests on a case-by-base
basis.
V. Future Actions
A. What Action Will Be Taken To
Determine if This Reactivity-Based
Regulation Is Effective?
The EPA will continue to work with
CARB to evaluate how VOC emissions
from this source category change in
response to the regulation and how
these emission changes will affect
ambient air quality. We will also
continue to work with CARB to evaluate
the appropriateness of MIR values for
VOC reactivity ranking under the
environmental conditions of interest in
California. The EPA’s proposed
approval of CARB’s aerosol coatings
regulation is predicated, in part, on
CARB’s commitment to ensuring that
the regulation in fact achieves the
intended environmental goals. The
CARB’s SIP submittal letter 50 states that
CARB officials ‘‘[i]ntend to follow the
implementation of this regulation
closely to ensure the air quality benefits
predicted are fully achieved. If they are
50 SIP submittal letter from Michael Kenny
(CARB) to Wayne Nastri (U.S. EPA, Region IX),
March 13, 2002.
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
not, CARB is obligated to identify and
secure additional regulatory measures to
meet our SIP commitments.’’
‘‘[M]oreover, if in fact the aerosol
coating regulation is not as effective as
predicted, we are fully prepared to
reevaluate the source category to
determine how best to achieve the most
stringent limits that are technologically
and commercially feasible.’’
B. How Will Future Uses of Relative
Reactivity Be Evaluated?
The CARB views the aerosol coatings
rule as a means to determine the
feasibility of additional reactivity-based
measures for other source categories.51
The EPA is working as a participant in
the RRWG to explore whether reactivitybased approaches are appropriate and
useful for other source categories and in
other parts of the country. Members of
the RRWG have a variety of research
projects underway to provide needed
information about the utility and
effectiveness of relative reactivity-based
VOC controls. The EPA is committed to
the process begun under the RRWG of
assuring that future applications of the
relative reactivity approaches are based
on a sound scientific foundation and are
practical, enforceable, and effective.
VI. Statutory and Executive Order
Reviews
A. Executive Order 12866: Regulatory
Planning and Review
Under Executive Order 12866, (58 FR
51735, October 4, 1993) the Agency
must determine whether the regulatory
action is ‘‘significant’’ and therefore
subject to the Office of Management and
Budget (OMB) review and the
requirements of the Executive Order.
The Order defines ‘‘significant
regulatory action’’ as one that is likely
to result in a rule that may:
(1) Have an annual effect on the
economy of $100 million or more or
adversely affect in a material way the
economy, a sector of the economy,
productivity, competition, jobs, the
environment, public health or safety, or
State, local, or tribal governments or
communities;
(2) Create a serious inconsistency or
otherwise interfere with an action taken
or planned by another agency;
(3) Materially alter the budgetary
impact of entitlements, grants, user fees,
or loan programs or the rights and
obligations of recipients thereof; or
51 California Air Resources Board, ‘‘Initial
Statement of Reasons for the Proposed
Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from
Aerosol Coating Products,’’ Chapter II, page 18, May
5, 2000.
PO 00000
Frm 00014
Fmt 4701
Sfmt 4702
(4) Raise novel legal or policy issues
arising out of legal mandates, the
President’s priorities, or the principles
set forth in the Executive Order.
For the change in definition of VOCs,
EPA has determined that this proposed
rule is not a ‘‘significant regulatory
action’’ under the terms of Executive
Order 12866 and is therefore not subject
to OMB review. For the proposed
approval of CARB’s rule into the SIP,
OMB has exempted this regulatory
action from Executive Order 12866
review.
B. Paperwork Reduction Act
For the change in the definition of
VOCs, this proposed rule does not
contain any information collection
requirements subject to OMB review
under the Paperwork Reduction Act, 44
U.S.C. 3501 et seq.
For the proposed approval of CARB’s
regulation into the SIP, this proposed
action does not contain any information
collection requirements that would
require any person to provide
information to EPA, however CARB’s
regulation contains requirements for the
aerosol coating industry to provide
information to CARB.
C. Regulatory Flexibility Act (RFA)
The RFA generally requires an agency
to prepare a regulatory flexibility
analysis of any rule subject to notice
and comment rulemaking requirements
under the Administrative Procedure Act
or any other statute unless the agency
certifies that the rule will not have a
significant economic impact on a
substantial number of small entities.
Small entities include small businesses,
small organizations, and small
governmental jurisdictions.
After considering the economic
impacts of today’s proposed rule on
small entities, I certify that this action
will not have a significant economic
impact on a substantial number of small
entities.
This proposed rule will not impose
any requirements on small entities.
Today’s change to the definition of VOC
does not directly regulate any entities.
The RFA analysis does not consider
impacts on entities which the action in
question does not regulate. See Motor &
Equipment Manufacturers Ass’n v.
Nichols, 142 F. 3d 449, 467 (D.C. Cir.
1998); United Distribution Cos. v. FERC,
88 F. 3d 1105, 1170 (D.C. Cir. 1996),
cert. denied, 520 U.S. 1224 (1997).
For the proposed approval of CARB’s
regulation into the SIP, this proposed
rule will not have a significant impact
on a substantial number of small entities
because SIP approvals under section
110 and subchapter I, part D of the CAA
E:\FR\FM\07JAP2.SGM
07JAP2
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
do not create any new requirements but
simply act on requirements that the
State is already imposing. Therefore,
because the Federal SIP approval does
not create any new requirements, I
certify that this action will not have a
significant economic impact on a
substantial number of small entities.
Moreover, due to the nature of the
Federal-State relationship under the
CAA, preparation of flexibility analysis
would constitute Federal inquiry into
the economic reasonableness of State
action. The CAA forbids EPA to base its
actions concerning SIPs on such
grounds. Union Electric Co. v. U.S. EPA,
427 U.S. 246, 255–66 (1976); 42 U.S.C.
7410(a)(2).
D. Unfunded Mandates Reform Act
Title II of the Unfunded Mandates
Reform Act of 1995 (UMRA), Public
Law 104–4, establishes requirements for
Federal agencies to assess the effects of
their regulatory actions on State, local,
and tribal governments and the private
sector. Under section 202 of UMRA,
EPA generally must prepare a written
statement, including a cost-benefit
analysis, for proposed and final rules
with ‘‘Federal mandates’’ that may
result in expenditures by State, local,
and tribal governments, in the aggregate,
or the private sector, of $100 million or
more in any 1 year. Before promulgating
an EPA rule for which a written
statement is needed, section 205 of
UMRA generally requires EPA to
identify and consider a reasonable
number of regulatory alternatives and
adopt the least costly, most costeffective or least burdensome alternative
that achieves the objectives of the rule.
The provisions of section 205 do not
apply when they are inconsistent with
applicable law. Moreover, section 205
allows EPA to adopt an alternative other
than the least costly, most cost-effective
or least burdensome alternative if the
Administrator publishes with the final
rule an explanation why that alternative
was not adopted. Before EPA establishes
any regulatory requirements that may
significantly or uniquely affect small
governments, including tribal
governments, it must have developed
under section 203 of UMRA a small
government agency plan. The plan must
provide for notifying potentially
affected small governments, enabling
officials of affected small governments
to have meaningful and timely input in
the development of EPA regulatory
proposals with significant Federal
intergovernmental mandates, and
informing, educating, and advising
small governments on compliance with
the regulatory requirements.
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
For the proposed change in the
definition of VOCs, today’s rulemaking
contains no Federal mandates (under
the regulatory provisions of title II of the
UMRA) for State, local, or tribal
governments or the private sector.
For the proposed approval of CARB’s
regulation into the SIP, EPA has
determined that the proposed approval
action does not include a Federal
mandate that may result in estimated
costs of $100 million or more to either
State, local, or tribal governments in the
aggregate, or to the private sector. This
Federal action proposes to approve preexisting requirements under State or
local law, and imposes no new
requirements. Accordingly, no
additional costs to State, local, or tribal
governments, or to the private sector,
result from this action.
Thus, today’s rule is not subject to the
requirements of sections 202 and 205 of
UMRA.
In addition, EPA has determined that
this rule contains no regulatory
requirements that might significantly or
uniquely affect small governments in
accordance with section 203 of UMRA.
E. Executive Order 13132: Federalism
Executive Order 13132, entitled
‘‘Federalism’’ (64 FR 43255, August 10,
1999), requires EPA to develop an
accountable process to ensure
‘‘meaningful and timely input by State
and local officials in the development of
regulatory policies that have federalism
implications.’’ ‘‘Policies that have
federalism implications’’ is defined in
the Executive Order to include
regulations that have ‘‘substantial direct
effects on the States, on the relationship
between the national government and
the States, or on the distribution of
power and responsibilities among the
various levels of government.’’
This proposed rule does not have
federalism implications. It will not have
substantial direct effects on the States,
on the relationship between the national
government and the States, or on the
distribution of power and
responsibilities among the various
levels of government, as specified in
Executive Order 13132. Today’s
proposed rule does not impose any new
mandates on State or local governments.
The change to the definition of VOCs
merely assists CARB in implementing
its aerosol coatings reactivity regulation.
The proposed approval of this
regulation into the SIP acts on a State
regulation implementing a Federal
standard, and does not alter the
relationship or the distribution of power
and responsibilities established in the
CAA. Thus, Executive Order 13132 does
not apply to this rule.
PO 00000
Frm 00015
Fmt 4701
Sfmt 4702
1653
In the spirit of Executive Order 13132,
and consistent with EPA policy to
promote communications between EPA
and State and local governments, EPA
specifically solicits comment on this
proposed rule from State and local
officials.
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
Executive Order 13175, entitled
‘‘Consultation and Coordination with
Indian Tribal Governments’’ (65 FR
67249, November 9, 2000), requires EPA
to develop an accountable process to
ensure ‘‘meaningful and timely input by
tribal officials in the development of
regulatory policies that have tribal
implications.’’ This proposed rule does
not have tribal implications, as specified
in Executive Order 13175. The proposed
change to the definition of VOCs merely
assists CARB in implementing its
aerosol coatings reactivity regulation
and does not impose any direct
compliance costs. The proposed
approval of CARB’s regulation into the
SIP acts on a State regulation and does
not alter the relationship between the
Federal government and Indian Tribes,
as specified in Executive Order 13175.
Thus, Executive Order 13175 does not
apply to this rule. The EPA specifically
solicits additional comment on this
proposed rule from tribal officials.
G. Executive Order 13045: Protection of
Children From Environmental Health
and Safety Risks
Executive Order 13045: ‘‘Protection of
Children from Environmental Health
and Safety Risks’’ (62 FR 19885, April
23, 1997) applies to any rule that: (1) Is
determined to be ‘‘economically
significant’’ as defined under Executive
Order 12866, and (2) concerns an
environmental health or safety risk that
EPA has reason to believe may have a
disproportionate effect on children. If
the regulatory action meets both criteria,
the Agency must evaluate the
environmental health or safety effects of
the planned rule on children, and
explain why the planned regulation is
preferable to other potentially effective
and reasonably feasible alternatives
considered by the Agency.
While this proposed rule is not
subject to the Executive Order because
it is not economically significant as
defined in Executive Order 12866, we
have reason to believe that ozone has a
disproportionate effect on active
children who play outdoors. (See 62 FR
38856 and 38859 July 18, 1997).
However, we do not expect today’s
proposed approval of CARB’s regulation
into the SIP to result in an adverse
E:\FR\FM\07JAP2.SGM
07JAP2
1654
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 / Proposed Rules
impact, as it is intended to be an ozone
neutral action. The CARB has indicated
that they have designed their new
reactivity-based limits to achieve the
same ozone reductions as the massbased limits they supplant. Also, we do
not expect today’s proposed change to
the definition of VOC to result in any
adverse impact, because it increases the
number of compounds subject to
regulation as VOCs for the purpose of
California’s aerosol coatings reactivitybased regulation.
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution, or Use
This rule is not subject to Executive
Order 13211, ‘‘Actions That
Significantly Affect Energy Supply,
Distribution, or Use’’ (66 FR 28355, May
22, 2001) because it is not a significant
regulatory action under Executive Order
12866.
I. National Technology Transfer
Advancement Act
Section 12(d) of the National
Technology Transfer Advancement Act
of 1995 (‘‘NTTAA’’), Public Law No.
104–113, § 12(d) (15 U.S.C. 272 note)
directs EPA to use voluntary consensus
standards in its regulatory activities
unless to do so would be inconsistent
with applicable law or otherwise
impractical. Voluntary consensus
standards are technical standards (e.g.,
materials specifications, test methods,
sampling procedures, and business
practices) that are developed or adopted
by voluntary consensus standards
bodies. The NTTAA directs EPA to
provide Congress, through OMB,
VerDate jul<14>2003
18:33 Jan 06, 2005
Jkt 205001
explanations when the Agency decides
not to use available and applicable
voluntary consensus standards.
For the change in definition of VOCs,
this proposed rulemaking does not
involve technical standards. Therefore,
EPA is not considering the use of any
voluntary consensus standards. For the
proposed approval of CARB’s regulation
into the SIP, the State regulation
references standard test methods and
makes modifications to American
Society for Testing and Materials
(ASTM) D3074–94, D3063–94 and
D2879–97 to support the regulatory
objectives.
The EPA welcomes comments on this
aspect of the proposed rulemaking and,
specifically, invites the public to
identify potentially-applicable
voluntary consensus standards and to
explain why such standards should be
used in this regulation.
List of Subjects
40 CFR Part 51
Environmental protection,
Administrative practice and procedure,
Air pollution control, Carbon monoxide,
Intergovernmental relations, Lead,
Nitrogen dioxide, Ozone, Particulate
matter, Reporting and recordkeeping
requirements, Sulfur oxides, Volatile
organic compound.
40 CFR Part 52
Environmental protection, Air
pollution control, Intergovernmental
relations, Ozone, Reporting and
recordkeeping requirements, Volatile
organic compound.
PO 00000
Authority: 42 U.S.C. 7401 et seq.
Frm 00016
Fmt 4701
Sfmt 4702
Dated: December 29, 2004.
Michael O. Leavitt,
Administrator.
PART 51—REQUIREMENTS FOR
PREPARATION, ADOPTION, AND
SUBMITTAL OF IMPLEMENTATION
PLANS.
1. The authority citation for part 51
continues to read as follows:
Authority: 42 U.S.C. 7401, 7411, 7412,
7413, 7414, 7470–7479, 7501–7508, 7601,
and 7602.
2. Section 51.100 is proposed to be
amended by adding paragraph (s)(6) as
follows:
§ 51.100
Definitions.
*
*
*
*
*
(s) * * *
(6) For the purposes of determining
compliance with California’s aerosol
coatings reactivity-based regulation, (as
described in the California Code of
Regulations, Title 17, Division 3,
Chapter 1, Subchapter 8.5, Article 3),
any organic compound in the volatile
portion of an aerosol coating is counted
towards that product’s reactivity-based
limit. Therefore, the compounds
identified in this section [i.e., §51.100
(s)] as negligibly reactive and excluded
from EPA’s definition of VOCs are to be
counted towards a product’s reactivity
limit for the purposes of determining
compliance with California’s aerosol
coatings reactivity-based regulation.
*
*
*
*
*
[FR Doc. 05–346 Filed 1–6–05; 8:45 am]
BILLING CODE 6560–50–P
E:\FR\FM\07JAP2.SGM
07JAP2
Agencies
[Federal Register Volume 70, Number 5 (Friday, January 7, 2005)]
[Proposed Rules]
[Pages 1640-1654]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-346]
[[Page 1639]]
-----------------------------------------------------------------------
Part IV
Environmental Protection Agency
-----------------------------------------------------------------------
40 CFR Parts 51 and 52
Revisions to the California State Implementation Plan and Revision to
the Definition of Volatile Organic Compounds (VOC)--Removal of VOC
Exemptions for California's Aerosol Coating Products Reactivity-Based
Regulation; Proposed Rule
Federal Register / Vol. 70, No. 5 / Friday, January 7, 2005 /
Proposed Rules
[[Page 1640]]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 51 and 52
[OAR-2003-0200; FRL-7857-6]
Revisions to the California State Implementation Plan and
Revision to the Definition of Volatile Organic Compounds (VOC)--Removal
of VOC Exemptions for California's Aerosol Coating Products Reactivity-
Based Regulation
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: The EPA is proposing to approve a new consumer products
regulation as part of the California State Implementation Plan (SIP)
for ozone under the Clean Air Act (CAA) as amended in 1990. This
California regulation adopts an innovative approach to reduce ozone
formation from volatile organic compounds (VOC) in aerosol coating
products. The EPA is also proposing to approve the use of California's
Tables of Maximum Incremental Reactivity (MIR) to allow implementation
of the new regulation in California. We are also proposing to revise
EPA's definition of VOCs so that compounds which we previously
identified as negligibly reactive and exempt from EPA's regulatory
definition of VOCs will now count towards a product's reactivity-based
VOC limit for the purpose of California's aerosol coatings regulation.
We are taking comments on this proposal and we plan to follow with a
final action.
DATES: Comments must be received on or before March 8, 2005.
ADDRESSES: Submit your comments, identified by Docket ID No. OAR-2003-
0200, by one of the following methods:
Federal eRulemaking Portal: https://www.regulations.gov.
Follow the on-line instructions for submitting comments.
Agency Web site: https://www.epa.gov/edocket. EDOCKET,
EPA's electronic public docket and comment system, is EPA's preferred
method for receiving comments. Follow the on-line instructions for
submitting comments.
E-mail: a-and-r-Docket@epa.gov.
Fax: 202-566-1741.
Mail: OAR Docket: OAR-2003-0200, Environmental Protection
Agency, Mailcode: 6102T, 1200 Pennsylvania Ave., NW., Washington, DC
20460.
Hand Delivery: EPA/DC, Public Reading Room, Room B102, EPA
West Building, 1301 Constitution Avenue, NW., Washington, DC. Such
deliveries are only accepted during the Docket's normal hours of
operation, and special arrangements should be made for deliveries of
boxed information.
Instructions: Direct your comments to Docket ID No. OAR-2003-0200.
EPA's policy is that all comments received will be included in the
public docket without change and may be made available online at http:/
/www.epa.gov/edocket, including any personal information provided,
unless the comment includes information claimed to be Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Do not submit information that you consider to
be CBI or otherwise protected through EDOCKET, regulations.gov, or e-
mail. The EPA EDOCKET and the federal regulations.gov websites are
``anonymous access'' systems, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through EDOCKET or regulations.gov, your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses. For additional information about EPA's public
docket visit EDOCKET on-line or see the Federal Register of May 31,
2002 (67 FR 38102).
For additional instructions on submitting comments, go to Unit I of
the SUPPLEMENTARY INFORMATION section of this document.
Docket: All documents in the docket are listed in the EDOCKET index
at https://www.epa.gov/edocket. Although listed in the index, some
information is not publicly available, i.e., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, is not placed on the Internet and will be
publicly available only in hard copy form. Publicly available docket
materials are available either electronically in EDOCKET or in hard
copy at the OAR Docket, OAR-2003-0200, EPA/DC, EPA West, Room B102,
1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. The telephone number for the Public Reading Room is
(202) 566-1744, and the telephone number for the OAR Docket is (202)
566-1742.
FOR FURTHER INFORMATION CONTACT: Stanley Tong, Rulemaking Office (AIR-
4), Environmental Protection Agency, Region IX, 75 Hawthorne St., San
Francisco, CA 94105; telephone number: (415) 947-4122; fax number:
(415) 947-3579; e-mail address: tong.stanley@epa.gov.
SUPPLEMENTARY INFORMATION:
I. General Information
A. What Should I Consider as I Prepare My Comments for EPA?
1. Submitting CBI. Do not submit this information to EPA through
EDOCKET, regulations.gov or e-mail. Clearly mark the part or all of the
information that you claim to be CBI. For CBI information in a disk or
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as
CBI and then identify electronically within the disk or CD ROM the
specific information that is claimed as CBI). In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
2. Tips for Preparing Your Comments. When submitting comments,
remember to:
i. Identify the rulemaking by docket number and other identifying
information (subject heading, Federal Register date and page number).
ii. Follow directions--The agency may ask you to respond to
specific questions or organize comments by referencing a Code of
Federal Regulations (CFR) part or section number.
iii. Explain why you agree or disagree; suggest alternatives and
substitute language for your requested changes.
iv. Describe any assumptions and provide any technical information
and/or data that you used.
v. If you estimate potential costs or burdens, explain how you
arrived at your estimate in sufficient detail to allow for it to be
reproduced.
vi. Provide specific examples to illustrate your concerns, and
suggest alternatives.
vii. Explain your views as clearly as possible, avoiding the use of
profanity or personal threats.
[[Page 1641]]
viii. Make sure to submit your comments by the comment period
deadline identified.
ix. Please strictly limit comments to the subject matter of this
proposal, the scope of which is discussed below. Please identify the
section/subsection on which you are commenting so we can group similar
comments together and better understand the context of your comment.
x. EPA requests that you also send a copy of your comments to:
Andrew Steckel, Rulemaking Office Chief (AIR-4), U.S. Environmental
Protection Agency, Region IX, 75 Hawthorne Street, San Francisco, CA
94105-3901.
3. Docket Copying Costs. A reasonable fee may be charged for
copying.
B. How Do I Request a Public Hearing?
If you wish to request a public hearing to submit comments
concerning this proposal please contact Mr. Stanley Tong, Rulemaking
Office (AIR-4), U.S. Environmental Protection Agency, 75 Hawthorne
Street, San Francisco, CA 94105, telephone (415) 947-4122. Requests for
a public hearing must be made by January 27, 2005. The EPA will publish
a notice of a hearing, if a hearing is requested, in the Federal
Register. Because the State has already held a public notice and
comment period for its aerosol coatings rule, any EPA hearing will be
strictly limited to the proposed EPA approval of the rule and its
inclusion in the California SIP and to the proposed change in the
definition of VOCs for 40 CFR 51.100(s). The hearing will not cover the
reactivity limits or other specifics of California's rule. If a public
hearing is requested, it will be held near our Region IX office in San
Francisco, CA.
C. Throughout This Document, ``We,'' ``Us'' and ``Our'' Refer to EPA
D. How Can I Get Copies of This Document and Other Related Information?
1. In addition to accessing the official public docket at https://
www.epa.gov/edocket/, you can also inspect copies of the submitted SIP
revision at our Region IX office during normal business hours. EPA
requests that you contact the person listed in the For Further
Information Contact section to schedule your inspection. You may also
see copies of the submitted SIP revision during normal business hours
by appointment at the California Air Resources Board, Stationary Source
Division, Rule Evaluation Section, 1001 ``I'' Street, Sacramento, CA
95814.
2. A copy of California's aerosol coating products regulation can
also be downloaded from the following internet addresses. Please be
advised that these are not EPA Web sites and may not contain the same
version of the regulations that were submitted to EPA. https://
www.arb.ca.gov/consprod/regs/aeropnt.pdf https://www.arb.ca.gov/
consprod/regs/Aeropnt.doc
Table of Contents
I. The State's Submittal.
A. What regulations did the State submit?
B. Are there other versions of this regulation?
C. What is the purpose of the submitted CARB regulation?
III. EPA's Evaluation and Action.
A. How is EPA evaluating the regulation?
B. Does the regulation meet the evaluation criteria?
C. Public comment and final action.
IV. Background Information.
A. Why was this regulation submitted?
B. What is photochemical reactivity?
C. Why is use of the relative reactivity concept appropriate in
California's aerosol coatings rule?
D. Are California's relative reactivity-based regulations
appropriate for areas outside of California?
E. How will the effectiveness of this reactivity-based program
be evaluated?
F. How has CARB addressed concerns about air toxics and ozone-
depleting substances?
G. What changes in enforcement strategies will likely occur due
to this relative reactivity-based regulation?
IV. Summary of CARB's Aerosol Coatings Regulation.
A. What does CARB's regulation require?
V. Future Actions.
A. What action will be taken to determine if this reactivity-
based regulation is effective?
B. How will future uses of relative reactivity be evaluated?
VI. Statutory and Executive Order Reviews.
I. The State's Submittal
A. What Regulations Did the State Submit?
Table 1 lists the regulations addressed by this proposal with the
date that they were adopted and submitted to EPA by the California Air
Resources Board (CARB).
Table 1.--Submitted Regulations
------------------------------------------------------------------------
Regulation title Adopted Submitted
------------------------------------------------------------------------
Aerosol Coating Products...................... 5/1/2001 3/13/2002
Tables of Maximum Incremental Reactivity (MIR) 5/1/2001 3/13/2002
Values.......................................
------------------------------------------------------------------------
On May 7, 2002, we found that this submittal meets the completeness
criteria in 40 CFR Part 51, Appendix V, as required before formal EPA
review.
B. Are There Other Versions of This Regulation?
There is no previous version of the aerosol coating products
regulation approved by EPA into the SIP, although CARB adopted an
earlier version of this regulation on March 23, 1995, and submitted it
to us on December 18, 1998. On November 19, 1998, CARB adopted
amendments to this earlier regulation. The CARB did not submit these
amendments to us as a SIP revision. There is no previous stand-alone
version of the Tables of MIR values in the SIP applicable to aerosol
coatings. Today, we are proposing approval of the CARB aerosol coatings
rule submitted to us on March 13, 2002. While we can act on only the
most recently submitted version of this regulation, we have reviewed
materials CARB provided with the previous SIP submittals for
informational purposes. Thus, this version of the aerosol coatings rule
replaces the earlier versions developed by CARB and, if we approve it,
will be the first such rule in the California SIP.
C. What Is the Purpose of the Submitted CARB Regulation?
The regulation covers aerosol coatings, aerosol clear coatings, and
aerosol stains. It applies to any person who sells, supplies, offers
for sale, applies, or manufactures for use in California any aerosol
coating subject to the limits in the regulation. The regulation imposes
reactivity-based VOC limits on these products for purposes of reducing
ozone caused by VOC emissions.
In the current SIP submittal, CARB has developed a new approach for
regulating VOC emissions from aerosol coatings. Traditionally, the VOC
emissions from aerosol and other coatings have been controlled by
limiting the mass of all VOCs in a product, and VOC content limits of
aerosol coatings were expressed as a maximum percent by mass of all
VOC. The new approach taken by CARB incorporates the concept of VOC
photochemical reactivity. This concept relies on the fact that the same
weight/amount of some VOCs (e.g., xylene) has the potential to form
more ozone, or to form ozone more quickly, than the same weight/amount
of other VOCs (e.g., propane) once they are emitted into the ambient
air under the same conditions.
The CARB estimates that its previous mass-based VOC control rule
for aerosol coatings resulted in statewide aerosol coating VOC
emissions reductions of 9
[[Page 1642]]
tons per day (tpd) from the 1989 baseline estimated VOC emissions of 30
tpd of VOC. The CARB calculates that the new reactivity-based aerosol
coatings rule in the current submittal would achieve the ``equivalent''
of an additional 3.1 tpd of VOC mass-based reductions statewide. In
other words, CARB estimates that this rule will achieve reactivity-
based VOC reductions that would be the equivalent of 12.1 tons of mass-
based VOC reductions from the 1989 baseline, measured in terms of ozone
reduction. The CARB intends its new regulation to encourage
manufacturers to reduce use of VOCs with higher reactivity, thereby
achieving more ozone reductions than through traditional VOC mass-based
regulations.
III. EPA's Evaluation and Action
A. How Is EPA Evaluating the Regulation?
Generally, SIP regulations must be enforceable (see section
110(a)(2)(A) of the CAA), must at a minimum require Reasonably
Available Control Technology (RACT) and Reasonably Available Control
Measures (RACM) in nonattainment areas (see, for example, sections
172(c)(1), 182(a)(2)(A) and 182(b)(2)), must not interfere with
attainment and reasonable further progress or any other applicable
requirement of the CAA, and must achieve the pollution reduction
requirements of the CAA (see section 110(l)). The CARB's aerosol
coatings regulation applies to both ozone attainment and non-attainment
areas statewide. Because this regulation covers nonmajor area sources
that are not covered by a Control Techniques Guidelines (CTG) document,
it is not subject to the RACT requirements for ozone nonattainment
areas (CAA, section 182(b)(2)).
Guidance and policy documents that we used to help evaluate
enforceability requirements includes: Issues Relating to VOC Regulation
Cutpoints, Deficiencies, and Deviations; Clarification to Appendix D of
November 24, 1987 Federal Register,'' (Blue Book), May 25, 1988,
(revised 1/11/90), Office of Air Quality Planning and Standards. We
also relied on several technical reports and journals to evaluate
CARB's SIP submittal. These reports and journals are referenced in
footnotes in the body of this proposal and are included in the docket
for this proposal.
B. Does the Regulation Meet the Evaluation Criteria?
We believe that the aerosol coatings rule will improve the SIP by
establishing stringent VOC limits for this product category, by
improving enforcement through labeling and reporting requirements, and
by creating an incentive for the use of solvents with relatively low
contribution to ozone formation. The regulation is generally consistent
with relevant policy and guidance regarding enforceability. Our
approval of the rule would also be consistent with CAA section 110(l),
because there is no prior version of the aerosol coatings regulation in
the SIP and ozone reductions resulting from the approval of this
regulation into the SIP will help in the State's efforts to achieve
attainment with the national ambient air quality standard (NAAQS) for
ozone. RACT requirements do not apply to the source category covered by
the CARB rule because RACT applies to major stationary sources in
nonattainment areas and source categories covered by a CTG. Because of
their widespread use in relatively small amounts, aerosol coatings are
considered area sources rather than major stationary sources. EPA has
not issued a CTG or a rule for this category. However, even though
federal RACT or consumer product requirements do not yet apply, CARB
took the initiative in 1995 to go beyond basic federally mandated VOC
reduction requirements by adopting an aerosol coatings regulation with
two tiers of aggressive mass-based VOC limits. In its current SIP
submittal, CARB is amending its existing regulation by replacing the
mass-based limits with reactivity-based limits intended to achieve
additional ozone reduction benefits.
Although CARB's existing mass-based aerosol coatings regulation has
significantly reduced emissions from aerosol coatings, CARB has
concluded that more reductions are needed to help reduce the high ozone
concentrations in Southern California and the Central Valley. The CARB
also believes that some VOC mass-based limits in the previous version
of the rule presented particularly difficult reformulation challenges
for manufacturers of water-based coatings,\1\ and the State concluded
that it may not be feasible to achieve additional VOC reductions from a
traditional VOC mass-based program. The current SIP submittal relies on
the relative reactivity concept, that is, the fact that individual
species of VOC react in the atmosphere to form different amounts of
ozone or to form ozone at different rates. The CARB hopes to target VOC
emission reductions to better control a product's contribution to ozone
formation by encouraging reductions of higher reactivity VOCs, rather
than by treating all VOCs in a product alike through a mass-based rule.
The submitted regulation therefore consists of reactivity-based limits
that replace the existing mass-based VOC limits for aerosol spray
coatings.
---------------------------------------------------------------------------
\1\ California Air Resources Board, ``Initial Statement of
Reasons for the Proposed Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from Aerosol Coating Products,''
Chapter VII, page 60, May 5, 2000.
---------------------------------------------------------------------------
Although EPA is supportive of reactivity-based programs, we
recognize that they may be more complex to develop, enforce, and
evaluate than mass-based programs. As a result, it is particularly
important for us to evaluate the State agency's ability to implement
such programs. The CARB has addressed these concerns partly through an
extensive public process spanning over 3 years in the development of
the aerosol coatings rule. The CARB held eight public workshops and
over 20 meetings with industry, leading scientists, local air
districts, and EPA. The CARB also gathered detailed information on the
sales and composition of aerosol coatings, funded extensive research on
VOC reactivity scales and their applicability to environmental
conditions in California, and took steps intended to ensure that no
backsliding would occur from adoption of the relative-reactivity
approach. To account for potential changes in MIR values as scientific
knowledge improves, CARB also committed to improve and update its
program by including in its Board resolution \2\ the provision ``[t]o
review the Tables of Maximum Incremental Reactivity (MIR) Values 18
months after the effective date of the amendments, and every 18 months
thereafter, to determine if modifications to the MIR values are
warranted.'' The CARB will also ``[r]eview the reactivity-based limits
before January 1, 2007 to determine if modifications are necessary to
reflect changes to the MIR values and return to the Board with any
recommended modifications to the reactivity-based limits.'' \3\
---------------------------------------------------------------------------
\2\ State of California Air Resources Board Resolution 00-22,
June 22, 2000, Agenda Item No. 00-6-1.
\3\ State of California Air Resources Board Resolution 00-22,
June 22, 2000, Agenda Item No. 00-6-1.
---------------------------------------------------------------------------
Additional details about the comparison of reactivity-based
reductions to VOC mass-based reductions, the appropriateness of CARB's
reactivity research to areas outside of California, and the evaluation
of the effectiveness of CARB's regulation are provided in the
Background section below.
[[Page 1643]]
Information normally found in a Technical Support Document (TSD) is
incorporated into this proposed rule. A separate TSD has not been
written for this proposed rulemaking.
C. Public Comment and Final Action
Because EPA believes the submitted aerosol coatings regulation
fulfills all relevant requirements, we are proposing to approve it into
the California SIP as authorized in section 110(k)(3) of the CAA. We
are also proposing to approve the use of CARB's Tables of MIR values in
California for the purpose of implementation of the aerosol coatings
regulation. We intend to grant SIP credit for the ozone equivalent VOC
mass-based reductions that are achieved by CARB's reactivity-based
regulation. Details on the methodology CARB used to determine the
equivalent VOC mass-based tonnage reduction achieved by its reactivity
regulation is discussed in the CARB staff report.\4\
---------------------------------------------------------------------------
\4\ California Air Resources Board, ``Initial Statement of
Reasons for the Proposed Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from Aerosol Coating Products,''
Chapter II, page 37, May 5, 2000.
---------------------------------------------------------------------------
Currently, EPA's regulatory definition of VOC (40 CFR 51.100(s))
excludes certain compounds, such as methane and ethane, which EPA has
determined to have negligible photochemical reactivity with respect to
the formation of ozone. California's reactivity-based regulation,
however, requires the inclusion of the assigned MIR scale reactivity
value of each organic compound present in the volatile portion of a
product, even if the compound's reactivity value is so low that EPA has
previously determined it to be negligibly reactive and therefore
exempt.
In order to approve CARB's aerosol coatings rule, EPA proposes to
modify our regulatory definition of VOC so that compounds previously
excluded will now be counted towards a product's reactivity-based VOC
limit for the limited purpose of CARB's aerosol coatings reactivity-
based regulation. Under 40 CFR 51.100(s), EPA has excluded compounds
from the definition of VOC in recognition of the fact that individual
organic compounds differ with respect to their incremental contribution
to ozone formation. EPA's exemption-based system separates organic
compounds into reactive and negligibly reactive compounds. The CARB's
reactivity-based regulation makes this distinction unnecessary because
CARB's rule assigns each compound a reactivity factor that accounts for
its relative contribution to ozone formation. These previously exempted
compounds will continue to be excluded from the Federal definition of
VOCs for other purposes.
We will accept comments from the public on this proposed approval
of the CARB aerosol rule into the SIP and the proposed modification of
our definition of VOC for the next 60 days. Unless we receive
convincing new information during the comment period, we intend to
publish a final approval action that will incorporate the regulations
listed in Table 1 into the federally enforceable SIP and modify our
definition of VOC to support CARB's aerosol coating rule.
The EPA, with CARB's assistance, intends to evaluate the
performance of this reactivity-based regulation in 3 years. This will
allow time to compile data on the implementation of, and compliance
with, the regulation, and will allow time to conduct additional
technical analysis such as modeling efforts needed to evaluate the
effect of the regulation on ambient ozone levels. We encourage CARB to
use this time to collect data on the costs and effectiveness of this
regulation, both to the regulated entities and to the regulators. In
particular, EPA is interested in how implementation of this regulation
affects the development of detailed emission inventories, as well as
industry compliance costs, including recordkeeping and compliance
testing, manufacturing or material costs, product quality and price.
Towards this goal, we are relying upon CARB's Board resolution \5\
which ``[d]irects the Executive Officer to take the following actions:
(1) Monitor the progress of manufacturers in meeting the reactivity-
based VOC limits, (2) propose any future regulatory modifications that
may be appropriate, and (3) continue to evaluate emerging technologies
for aerosol coatings to determine if additional ozone reductions will
be feasible in the future.''
---------------------------------------------------------------------------
\5\ State of California Air Resources Board Resolution 00-22,
June 22, 2000, Agenda Item No. 00-6-1.
---------------------------------------------------------------------------
The proposed approval of CARB's aerosol coatings regulation based
upon VOC reactivity is limited to this source category for this State.
EPA believes that relative reactivity-based regulations may help
provide the flexibility necessary to achieve further emissions
reductions from some source categories to address persistent ozone
nonattainment problems in areas of the country that need further
reductions in VOC emissions to come into attainment with federal ozone
standards. EPA is committed to continuing its support of research on
the suitability of relative reactivity-based regulations to other
geographic regions and to other source categories through the national
Reactivity Research Working Group (RRWG) of which CARB and EPA are
members.\6\ The purpose of the RRWG is to encourage and sponsor
research on scientific questions concerning VOC reactivity which may be
of interest to regulators. This group is affiliated with NARSTO
(formerly known as the North American Research Strategy for
Tropospheric Ozone) and is a voluntary organization currently composed
of industry, government and academic representatives. The group has an
open membership and anyone may attend the meetings and participate.
---------------------------------------------------------------------------
\6\ See ``VOC Reactivity'' at https://www.cgenv.com/Narsto/.
---------------------------------------------------------------------------
The EPA is specifically seeking public comment on how reactivity-
based programs might affect industry compliance and recordkeeping costs
to support effective implementation and enforcement, and how industry
and regulatory agency costs and staff requirements might change with
respect to emission inventories.
We are not seeking comments on the reactivity limits or other
specifics of CARB's rule; nor are we seeking comments on EPA's VOC
exemption process. The EPA has previously published in 63 FR 48792
(September 11, 1998) its views on reactivity as it relates to the
regulation of VOC emissions from consumer products pursuant to CAA
Sec. 183(e) and this proposal should not be construed as a change in
the Agency's interpretation of that provision. When commenting, please
indicate which section of this proposal you are commenting on so we can
group similar comments together.
III. Background Information
A. Why Was This Regulation Submitted?
Ground level ozone, commonly referred to as ``smog,'' is a serious
air pollutant that harms human health and the environment. Ground level
ozone is a complex problem that is difficult to control in part because
ozone is not emitted directly by specific sources. It forms in the air
when there are chemical reactions between nitrogen oxides
(NOX) and VOCs in the presence of heat and sunlight.
Therefore, one way to reduce ozone levels in many areas is to control
emissions of VOCs. Section 110(a) of the CAA requires States to submit
regulations that control VOC emissions as part of the State's SIP.
B. What Is Photochemical Reactivity?
There are thousands of individual species of VOC chemicals that can
[[Page 1644]]
combine with NOX and the energy from sunlight to form ozone.
The impact of a given VOC on formation of ground-level ozone is
sometimes referred to as its ``reactivity.'' It is generally understood
that not all VOCs are equal in their effects on ground-level ozone
formation. Some VOCs react extremely slowly and changes in their
emissions have limited effects on ozone pollution episodes. Some VOCs
form ozone more quickly, or they may form more ozone than other VOCs.
Others not only form ozone themselves, but also enhance ozone formation
from other VOCs. By distinguishing between more reactive and less
reactive VOCs, however, it should be possible to decrease ozone
concentrations further or more efficiently than by controlling all VOCs
equally.
Assigning a value to the reactivity of a compound is not
straightforward. Reactivity is not simply a property of the compound
itself; it is a property of both the compound and the environment in
which the compound is found. The reactivity of a single compound varies
with VOW-NOX ratios, meteorological conditions, the mix of
other VOCs in the atmosphere, and the time interval of interest.
Designing an effective regulation that takes account of these
interactions is difficult, and implementing and enforcing such a
regulation carries the extra burden of characterizing and tracking the
full chemical composition of VOC emissions.
1. History of EPA's VOC Policy
Historically, EPA's general approach to regulation of VOC emissions
has been based upon control of total VOCs by mass, without
distinguishing between individual species of VOC. EPA considered the
regulation of VOCs by mass to be the most effective and practical
approach based upon the scientific and technical information available
when EPA developed its VOC control policy.
EPA issued the first version of its VOC control policy in 1971, as
part of EPA's SIP preparation guidance.\7\ In that guidance, EPA
emphasized the need to reduce the total mass of VOC emissions, but it
also suggested that substitution of one compound for another might be
useful when it would result in a clearly evident decrease in reactivity
and thus tend to reduce photochemical oxidant formation. This latter
statement encouraged States to promulgate SIPs with VOC emission
substitution provisions similar to the Los Angeles County Air Pollution
Control District's (LACAPCD) Rule 66,\8\ which allowed some VOCs that
were believed to have low to moderate reactivity to be exempted from
control. The exempt status of many of those VOCs was questioned a few
years later, when research results indicated that, although some of
those compounds do not produce much ozone close to the source, they may
produce significant amounts of ozone after they are transported
downwind from urban areas.\9\
---------------------------------------------------------------------------
\7\ U.S. Environmental Protection Agency. ``Requirements for
Preparation, Adoption, and Submittal of Implementation Plans.''
Federal Register, 36 FR 15486-15506 (1971).
\8\ County of Los Angles, Air Pollution Control District (1972).
Rules and Regulations. Rule 66 (1966). Amended November 2, 1972.
\9\ Dimitriades, B. ``Oxidant/03 Air Quality Benefits from
Emission Substitution.'' In: ``Proceedings. Hydrocarbon Control
Feasibility. Its Impact on Air Quality'' (and references herein).
Speciality Conference, Air Pollution Control Association, April,
1977.
---------------------------------------------------------------------------
In 1977, this research led EPA to issue the second version of its
VOC policy under the title ``Recommended Policy on Control of Volatile
Organic Compounds,'' (42 FR 35314, July 8, 1977) offering its own, more
limited list of exempt organic compounds. The 1977 policy identified
four compounds that have very low photochemical reactivity and
determined that their contribution to ozone formation and accumulation
could be considered negligible. The policy exempted these ``negligibly
reactive'' compounds from VOC emissions limitations in programs
designed to meet the ozone NAAQS. Since 1977, the EPA has added other
compounds to the list of negligibly reactive compounds based on new
information as it has been developed. In 1992, the EPA adopted a formal
regulatory definition of VOC for use in SIPs, which explicitly excludes
compounds that have been identified as negligibly reactive [40 CFR
51.100(s)]. To date, EPA has exempted 53 compounds or classes of
compounds in this manner.
In effect, EPA's current VOC exemption policy has resulted in a
two-bin system in which most compounds are treated equally as VOCs and
are controlled and a separate smaller group of compounds are treated as
negligibly reactive and are exempt from VOC control.\10\ This approach
was intended to encourage the reduction of emissions of all VOCs that
participate in ozone formation. From one perspective, it appears that
this approach has been relatively successful. EPA estimates that,
between 1970 and 2003, VOC emissions from man-made sources nationwide
have declined by 54 percent. This decline in VOC emissions has helped
to decrease average ozone concentration by 29 percent (based on 1-hour
averages) and 21 percent (based on 8-hour averages) between 1980 and
2003. These reductions have occurred even though, between 1970 and
2003, population, vehicle miles traveled, and gross domestic product
have risen 39 percent, 155 percent and 176 percent respectively.
[Latest Findings on National Air Quality: 2002 Status and Trends, EPA
454/K-03-001, August 2003; and The Ozone Report Measuring Progress
through 2003, EPA 454/K-04-001, April 2004; Environmental Protection
Agency, Office of Air Quality Planning and Standards, Research Triangle
Park, North Carolina]
---------------------------------------------------------------------------
\10\ It should be noted that EPA has also taken VOC reactivity
into consideration in other ways, such as the development of the
consumer and commercial product regulations under CAA Sec. 183(e).
EPA considered VOC reactivity as a factor in developing the federal
consumer products program as directed by the statute, and EPA's
approach was confirmed by the courts. See, Allied Local & Regional
Mfrs. Caucus v. EPA, 215 F.3d 61 (D.C. Cir. 2000), cert. denied 532
U.S. 1018 (2001). The EPA plans to develop its own regulation for
aerosol coating products under CAA Sec. 183(e). Our future
regulation may differ from CARB's regulation. If this turns out to
be the case, a process will need to be developed to verify that the
State's requirements and limits are at least as stringent as those
in the national standard.
---------------------------------------------------------------------------
On the other hand, some have argued that a reactivity-based
approach for reducing VOC emissions would be more effective than the
current mass-based approach. One group of researchers conducted a
detailed modeling study of the Los Angeles area and concluded that,
compared to the current approach, a reactivity-based approach could
achieve the same reductions in ozone concentrations at significantly
less cost--or for a given cost, could achieve a significantly greater
reduction in ozone concentrations.\11\ EPA recognizes that, in theory,
a well designed reactivity-based program, in which each individual VOC
is regulated more or less stringently based on its actual contribution
to ozone formation, would be more efficient than the current approach.
On the other hand, there are significant practical difficulties
involved in designing, implementing, and enforcing such a program. We
believe that the CARB program we are proposing to approve today will
help EPA and other States to evaluate whether the benefits of a
reactivity-based approach are sufficient to outweigh these practical
difficulties.
---------------------------------------------------------------------------
\11\ A. Russell, J. Milford, M. S. Bergin, S. McBride, L.
McNair, Y. Yang, W. R. Stockwell, B. Croes, ``Urban Ozone Control
and Atmospheric Reactivity of Organic Gases,'' Science, 269: 491-
495, (1995).
---------------------------------------------------------------------------
We also recognize that, in spite of the progress that most parts of
the country
[[Page 1645]]
have made in reducing ozone concentrations, further reductions in VOC
emissions will likely be needed to bring a number of areas into
attainment with the 8-hour ozone standard. In particular, in areas
where significant VOC emission controls are already in place, further
mass-based emission reductions may be difficult or very expensive to
achieve. In such situations, regulations that distinguish between
individual VOCs and create an incentive to shift production and use
from more reactive VOCs to less reactive VOCs may provide the
flexibility necessary to continue progress towards attainment of the
ozone NAAQS.
2. History of CARB's Reactivity Work
Regulatory authorities in California have been experimenting with
the concept of reactivity-based regulations for some time. The first
regulation in California that took reactivity into account was Rule
66,\12\ adopted in the mid 1960s by LACAPCD. This rule restricted
emissions of certain classes of compounds which were defined by the
rule as photochemically reactive based on their chemical structure
(e.g., compounds having olefinic type of unsaturation) to 40 pounds per
day, but allowed up to 3000 pounds per day emissions for many other
organic compounds which were not defined by the rule as photochemically
reactive. In other words, Rule 66 sought to regulate certain VOCs more
than others, based on the assumption that some VOCs participate more in
ozone formation. Rule 66 was very influential at the time and versions
of it were adopted by several other States. However, the VOC control
approach taken by Rule 66 has been superseded by EPA's definition of
VOC (57 FR 3941, February 3, 1992), which was based on the 1977 EPA
policy statement and which only exempted a smaller number of negligibly
reactive compounds.
---------------------------------------------------------------------------
\12\ The South Coast Air Quality Management District (SCAQMD),
the successor agency to LACAPCD, renamed this Rule 442.
---------------------------------------------------------------------------
Like EPA's 1977 policy, Rule 66 was really a ``two bin'' system
which tightly controlled certain compounds, which were defined as more
photochemically reactive, and applied a much lesser level of control to
a large class of compounds, which were regarded as less reactive. The
main difference between Rule 66 and the later EPA VOC definition
approach was the criteria for classifying compounds as exempt (or
subject to lesser control), with the EPA definition allowing a much
smaller group of compounds to be considered non-reactive or exempt.
In 1991 California adopted regulations intended to differentiate
between species of VOC based upon a reactivity scale, instead of a two
bin system. The 1991 rules were the Low-Emission Vehicles and Clean
Fuels regulations that CARB intended to reduce VOC emissions by mass
from motor vehicles generally, but which also took into account VOC
reactivity differences in organic gas when comparing the emissions from
alternatively fueled vehicles (AFVs).\13\ \14\ Although not a full-
blown attempt to regulate VOCs by their relative reactivity, CARB
nonetheless began the exploration of the MIR scale as a mechanism to
distinguish between VOCs and encourage reduction of more reactive VOCs.
---------------------------------------------------------------------------
\13\ California Air Resources Board ``Proposed Regulations for
Low-Emission Vehicles and Clean Fuels-Staff report and Technical
Support Document,'' State of California, Air Resources Board,
Sacramento, CA, August 13, 1990.
\14\ California Air Resources Board ``Proposed Regulations for
Low-Emission Vehicles and Clean Fuels-Final Statement of Reasons,''
State of California, Air Resources Board, July, 1991.
---------------------------------------------------------------------------
Today's proposal addresses CARB's most recent effort to utilize the
concept of VOC relative reactivity and the MIR scale to regulate VOC
emissions. This rule reflects a major shift from the traditional mass-
based control strategies for reduction of VOC emissions and introduces
this concept in a far more significant way than in CARB's previous
actions. In connection with the SIP submittal for this aerosol coatings
rule, CARB has provided additional supporting information in the form
of journal articles and reports which describe VOC reactivity research
efforts.
3. What Research Has Been Conducted in Reactivity?
Much of the work on reactivity scales that CARB used as a basis for
its aerosol coatings rule was done at the University of California at
Riverside by William P. L. Carter. Carter investigated 18 different
ozone reactivity scales.\15\ All of these scales are based on chamber
studies intended to evaluate the impact of a given VOC on ozone
formation under certain assumed conditions. The three most prominent
scales he developed were:
---------------------------------------------------------------------------
\15\ Carter, William P. L., ``Development of Ozone Reactivity
Scales for Volatile Organic Compounds,'' J. Air & Waste Manage.
Assoc., 44: 881-899, (1994).
---------------------------------------------------------------------------
i. Maximum Incremental Reactivity (MIR) scale--an ozone yield scale
derived by adjusting the NOX emissions in a base case to
yield the highest incremental reactivity of the base reactive organic
gas mixture.\16\
---------------------------------------------------------------------------
\16\ The CARB's reactivity regulation defines the term Reactive
Organic Compound (ROC) as any compound that has the potential, once
emitted to contribute to ozone formation in the troposphere. ROCs
include compounds which are excluded from EPA's definition of VOCs
as found in 40 CFR 51.100(s).
---------------------------------------------------------------------------
ii. Maximum Ozone Incremental Reactivity (MOIR) scale--an ozone
yield scale derived by adjusting the NOX emission in a base
case to yield the highest peak ozone concentration.
iii. Equal Benefit Incremental Reactivity (EBIR) scale--an ozone
yield scale derived by adjusting the NOX emissions in a base
case scenario so VOC and NOX reductions are equally
effective in reducing ozone.
In addition to Carter's work, there have been other attempts to
create reactivity scales. One such effort is the work of R. G. Derwent
and M. E. Jenkins, who have published articles on a scale called the
photochemical ozone creation potential (POCP) scale.\17\ This scale was
derived for the conditions prevalent in Europe. The POCP scale is
roughly consistent with those of Carter although, as expected, there
are some differences because the POCP scale is based on European
conditions.
---------------------------------------------------------------------------
\17\ See, for example, R. G. Derwent and M.E. Jenkin,
``Hydrocarbons and the Long-Range Transport of Ozone and PAN Across
Europe,'' Atmospheric Environment, 25A, No. 8, 1661-1678, (1991).
---------------------------------------------------------------------------
The CARB has relied most heavily on Carter's research for its
regulatory development and CARB has used the MIR scale for development
of the aerosol coating regulation.\18\ The MIR scale is designed using
certain assumptions about meteorological and environmental conditions
where ozone production is most sensitive to changes in hydrocarbon
emissions and, therefore, is intended to represent conditions where VOC
emission controls will be most effective. The MIR scale is expressed as
grams of ozone formed per gram of organic compound reacted. Each
compound is assigned an individual MIR value, which enables the
reactivities of different compounds to be compared quantitatively.
Individual MIR values now exist for many commonly used compounds, and a
list of these individual values comprises a scale.
---------------------------------------------------------------------------
\18\ California Air Resources Board, ``Initial Statement of
Reasons for the Proposed Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from Aerosol Coating Products,''
Chapter II, page 12, May 5, 2000.
---------------------------------------------------------------------------
To evaluate reactivity scales and ensure that VOC reactivity is
used appropriately in its proposals, CARB created the Reactivity
Scientific Advisory Committee (RSAC), a group of leading researchers in
the field of atmospheric science. This group reviews CARB's reactivity
related work
[[Page 1646]]
and convenes periodically in meetings which are open to the public to
comment on CARB's work.
The EPA has been closely following the scientific literature on
reactivity scales, and is interested in how such reactivity scales
might be applied to national programs or programs in other States.
Because reactivity depends on the characteristics of the environment as
well as the compound, scales are developed to represent a particular
set of environmental conditions in certain geographic locations. It is
not clear whether a single scale can represent actual ozone formation
over the whole country where meteorological and environmental
conditions vary considerably. Many scales, including the MIR scale are
derived for ozone formed during one day of reaction time. The EPA is
interested in whether such scales adequately represent the ozone
formation from VOCs during multi-day stagnation events or long-range
transport of pollutants, in such places as those seen in the Northeast
section of the country, which may take place over several days.
To help answer such questions, EPA and CARB are participating in
the RRWG, which sponsored three atmospheric photochemical modeling
studies to examine how changing the reactivity of the mix of VOC
emissions might affect ozone formation across wide geographical areas
over time. The three areas that researchers studied were the Houston
area, North Carolina, and the eastern half of the United States. The
EPA anticipates that these three studies and follow-up efforts will
help to answer many questions about the potential use of relative
reactivity in developing, implementing, and enforcing VOC regulatory
programs.
C. Why Is Use of the Relative Reactivity Concept Appropriate in
California's Aerosol Coatings Rule?
There are five classes of nonattainment for the 1-hour ozone
standard, ranging from marginal to extreme. The Los Angeles--South
Coast Air Basin Area and the San Joaquin Valley--San Joaquin Valley Air
Basin in California are currently the only areas in the nation in the
worst category of extreme nonattainment (40 CFR 81.305 and 69 FR
20550). Under the 8-hour standard, there are no areas classified under
the ``extreme'' ozone non-attainment category. South Coast is
classified as severe non-attainment and San Joaquin is classified as
serious non-attainment under the 8-hour standard. Because of the
elevated ozone levels in Los Angeles, the San Joaquin Valley and
elsewhere in California, CARB has adopted many innovative rules and
regulations to help reduce ozone precursor emissions. These efforts
include adopting regulations which go beyond current federally-mandated
VOC reduction requirements, such as regulating a wider variety of area
and mobile sources and establishing aggressive emission standards that
force development of new low-emission technologies.
As one such effort, CARB already adopted a statewide regulation in
1995 limiting the VOC mass content of 35 categories of aerosol
coatings. This regulation contained two tiers of VOC limits and a
provision to extend the compliance deadline for up to 5 years for each
aerosol coating category if it was determined that the limits were not
feasible. On November 19, 1998, CARB amended the regulation to relax
the limits for 12 coating categories after determining that the
original limits were not feasible even with the 5-year extension. CARB
made limits for 11 other categories more stringent. The CARB also
extended the compliance date to January 1, 2002, for all 35 product
categories covered by the aerosol coating rule to provide time for
manufacturers to comply with the new limits.
In the current SIP submittal, CARB has determined that even with
the extended compliance date, some of the VOC content limits remain
technologically challenging. In order to preserve the air quality
benefits of its 1998 rule, while at the same time allowing
manufacturers greater flexibility in reformulating their products, CARB
is replacing its pre-existing mass-based VOC limits for aerosol spray
coatings with reactivity-based limits that are designed to achieve
equivalent air quality benefits. The CARB's explicit goal was to
develop reactivity-based limits that would ensure that the ozone
reduction commitment from its second tier mass-based VOC limits would
not be compromised.\19\ For the reasons set forth below, EPA believes
that CARB's amended aerosol spray coating regulation achieves this
goal.
---------------------------------------------------------------------------
\19\ California Air Resources Board, ``Initial Statement of
Reasons for the Proposed Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from Aerosol Coating Products,''
Executive Summary, page 2, May 5, 2000.
---------------------------------------------------------------------------
1. Equivalency of Air Quality Benefits
i. Sufficient information about the source category. In order to
determine equivalent ozone reductions and set appropriate limits, CARB
collected detailed product speciation information and sales data from
manufacturers. For the aerosol coatings category, CARB found that over
80 percent of the species of VOCs typically used as ingredients were
well-studied and an additional 17 percent of the species typically used
would need only minor adjustment for uncertainty in their MIR values.
In other words, CARB concluded that the reactivity values of over 95
percent of the VOCs generally used in the specific category of aerosol
coatings were fairly well-studied and understood.\20\ The accuracy and
completeness of the VOC inventory, and the availability of
scientifically reviewed and published reactivity values for those VOCs
used in aerosol coatings may not be available for other consumer
product categories. The CARB's reactivity regulation defines the term
``reactive organic compound'', or ``ROCs,'' as any compound that has
the potential, once emitted, to contribute to ozone formation in the
troposphere. The ROCs include compounds which EPA has excluded from the
regulatory definition of VOCs found in 40 CFR 51.100(s). To minimize
confusion to the reader, we will continue to use the term ``VOC'' in
the remainder of this proposal, instead of ``ROC.'' When the term
``VOC'' is used in the context of CARB's reactivity-based aerosol
coatings rule, the reader should remember that this refers to all VOCs,
including those compounds that are excluded from EPA's regulatory
definition of VOC. The accurate identification and measurement of
individual VOC compounds and development of accurate MIR values is
crucial to the effectiveness of a reactivity program.\21\
---------------------------------------------------------------------------
\20\ California Air Resources Board, ``Initial Statement of
Reasons for the Proposed Amendments to the Regulation for Reducing
Volatile Organic Compound Emissions from Aerosol Coating Products,''
Chapter IV, page 36, May 5, 2000.
\21\ B.J. Finlayson-Pitts, J.N. Pitts Jr, ``Atmospheric
Chemistry of Tropospheric Ozone Formation: Scientific and Regulatory
Implications,'' J. Air Waste Manage. Assoc. 43:1091-1100, (1993).
---------------------------------------------------------------------------
ii. Sufficient information about the reactivity scale and its
applicability to California. In conjunction with this SIP submittal,
CARB provided a listing of approximately 50 research articles to help
support its conclusion that this aerosol coatings regulation based upon
VOC relative reactivity is appropriate for conditions in California and
that the MIR scale chosen by CARB is the most appropriate scale for
this regulation.
As stated earlier, CARB relies on the work of Carter in the
development of the scale for the aerosol coatings rule. Carter
investigated 18 different ozone reactivity scales and concluded
``[t]hat the MIR scale (or a scale similar to it,
[[Page 1647]]
such as one based on integrated ozone over the standard) is appropriate
for regulatory applications where a reactivity scale is required.''
\22\ He determined that, while different reactivity scales might give
different reactivity orderings of VOCs, for most VOC species the
general rankings among the different scales were very similar. He also
found that even relatively large variations in the base ROG mixture
\23\ had, in most cases, only a small effect on relative reactivity.
For example, a two-fold increase in the amount of aromatics in the base
mixture of VOCs in the chamber study resulted in less than a 20 percent
change in the relative MIR reactivity. From this it could be inferred
that significant changes in the ambient mixture of VOCs in the
atmosphere would not significantly change the relative MIR value.
---------------------------------------------------------------------------
\22\ W.P.L. Carter, ``Development of Ozone Reactivity Scales for
Volatile Organic Compounds,'' J. Air Waste Manage. Assoc. 44:881-
899, (1994).
\23\ From Carter's article on ``Development of Ozone Reactivity
Scales for Volatile Organic Compounds,'' the term ``base ROG
mixture'' means the mixture of Reactive Organic Gases (ROGs)
initially present or emitted in the Empirical Kinetic Modeling
Approach (EKMA) scenarios except for biogenic VOCs, VOCs present
aloft, or VOCs added for the purpose of calculating their
incremental reactivities.
---------------------------------------------------------------------------
The various studies conducted to date show good agreement in
reactivity values for most VOC species between normalized reactivity
scales generated by airshed models and Carter's box-modeled
calculations. For example, Bergin et al.,\24\ summarized a number of
papers comparing reactivity scales predicted by airshed models to those
predicted by Carter using a box-model. Most of the papers are based on
simulations conducted with the Carnegie Mellon/California Institute of
Technology model (CIT) for Los Angeles using the ozone episode of
August 27-29, 1987. Bergin reports that airshed model-derived spatially
weighted results behave similarly to MIRs.\25\ The report further
states that the greatest differences were found for formaldehyde and
other compounds whose reactivities were highly dependent on photolytic
reactions, and in general, airshed model results for Los Angeles agree
well with MIRs, and further show that individual organics have very
different ozone formation impacts.
---------------------------------------------------------------------------
\24\ M. Bergin, W.P.L. Carter, J. Milford, P.J. Ostrowski, A.G.
Russell, Reactivity Assessments, Reactivity Research Working Group
(May 5, 1999). (ftp://ftp.cgenv.com/pub/downloads/RRWGdoc/assess-
2.pdf).
\25\ M. Bergin, W.P.L. Carter, J. Milford, P.J. Ostrowski, A.G.
Russell, Reactivity Assessments, Reactivity Research Working Group,
Page 12, (May 5, 1999). (ftp://ftp.cgenv.com/pub/downloads/RRWGdoc/
assess-2.pdf).
---------------------------------------------------------------------------
While Bergin's reactivity assessment indicates a general support
for the concept of relative reactivity, she also points out that gaps
exist in the current knowledge base of the scientific community and
points to areas where further investigation is needed. For example,
Bergin acknowledges that although airshed model results for Los Angeles
agree well with MIRs, such a study has not been conducted for other
regions. Also, Bergin suggested that additional work is needed to
examine the effects of aromatics under several different conditions,
and that Eastern transport conditions should also be examined in a
multi-day scenario. The RRWG is currently reviewing studies which
examine the reactivities in the eastern half of the United States which
will help to answer some of these questions.
Similarly, recent work by Martien and Harley found that ``[f]or
most species studied'' * * * ``[r]eactivity scales developed by 3-D
modeling resulted in similar rankings of individual VOC when compared
to reactivity scales developed by Carter using a box model.'' \26\ They
also point out that ``[S]ite-to-site differences (in reactivity values)
can be large when absolute reactivity scales are considered. The
variation in reactivity across sites is reduced when reactivity is
measured on a relative rather than absolute scale. Differences in
relative reactivity may still occur as a function of location, with
differences likely to be magnified where absolute reactivities are
low.''
---------------------------------------------------------------------------
\26\ P. Martien, R.Harley, ``Development of Reactivity Scales
via 3-D Grid Modeling of California Ozone Episodes,'' Final report
prepared for California Air Resources Board, May 2002.
---------------------------------------------------------------------------
One study submitted by CARB to EPA attempts to address the issue of
whether the MIR scale adequately represents VOC reactivity in transport
scenarios. Kaduwela and his associates \27\ assessed for the first time
whether box-model based scales are applicable to regional-scale
domains, which include transport of pollutants through urban and rural
areas. They did this by conducting grid-based photochemical simulations
in a regional domain in central California for five compounds and found
a linear correlation between box-model based scales and regional grid-
based scales. These studies indicate a correlation between box-model
scales used in Carter's work and the more detailed scales. Therefore,
CARB concludes that the box-model's lack of physical detail and shorter
episode time does not limit the suitability of the MIR values with
respect to concerns about transport within California.
---------------------------------------------------------------------------
\27\ A. Kaduwela, V. Hughes, L. Woodlouse, P. Allen, J. DaMassa,
A. Ranzieri, ``Photochemical Reactivity of Organic Compounds in
Central California: A Grid-Based Modeling Study,'' Presented at
Stanford University, CA July 26-28, 1999.
---------------------------------------------------------------------------
During an October 1999 RSAC meeting, a member of the public asked
the RSAC whether the scenarios used to calculate MIRs are realistic.
The RSAC committee ``[r]esponded that the relative reactivity doesn't
change between scenarios and that, in a study which examined an
exposure metric calculated by a 3-D model, the relative reactivities
correlated well with MIRs.'' \28\ At the same meeting, a member of the
public also asked the RSAC if MIR conditions were appropriate for
California. The committee's response was that whether MIR conditions
were appropriate for California was a policy decision. The CARB's SIP
submittal states \29\ that ``[w]hile the MIR scale has been extensively
tested as appropriate for use in California, we caution that our
research has focused on California atmospheric conditions only. As
such, the suitability of using the MIR scale for regulatory purposes in
other parts of the United States has not been demonstrated, and may not
be appropriate.''
---------------------------------------------------------------------------
\28\ Minutes of the Reactivity Scientific Advisory Committee,
October 8, 1999, https://www.arb.ca.gov/research/reactivity/rsac/
oct99-min.html.
\29\ State Implementation Plan (SIP) Submittal letter from
Michael Kenny (CARB) to Wayne Nastri (US EPA, Region IX), March 13,
2002.
---------------------------------------------------------------------------
iii. Approach to Uncertainty. Although the MIR values are
calculated with what a peer reviewed report \30\ describes as a
``state-of-the-science'' chemical mechanism, the reactivity values of
some VOCs are still uncertain,\31\ while those of other VOCs have been
more thoroughly studied and will not likely change with further
research. To account for this uncertainty, CARB has applied Carter's
uncertainty ranking which defines 6 categories or ``bins'' to describe
the ``certainty'' of the chemical mechanism used to determine the MIR
values. The uncertainty scale is subjective, but it is described as
Carter's best judgment of the certaint