Designation of Areas for Air Quality Planning Purposes; State of Arizona; Pinal County; PM10, 60680-60689 [2010-24683]
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Federal Register / Vol. 75, No. 190 / Friday, October 1, 2010 / Proposed Rules
Farm, pending further consultation with
the affected tribes.
DATES: Any comments must arrive by
40 CFR Part 81
November 1, 2010.
ADDRESSES: Submit comments,
[EPA–R09–OAR–2010–0491; FRL–9209–4]
identified by docket number EPA–R09–
Designation of Areas for Air Quality
OAR–2010–0491, by one of the
Planning Purposes; State of Arizona;
following methods:
Pinal County; PM10
1. Federal eRulemaking Portal: https://
www.regulations.gov. Follow the on-line
AGENCY: Environmental Protection
instructions.
Agency (EPA).
2. E-mail: vagenas.ginger@epa.gov.
ACTION: Proposed rule.
3. Mail or deliver: Ginger Vagenas
(Air-2), U.S. Environmental Protection
SUMMARY: Pursuant to section 107(d)(3)
Agency Region IX, 75 Hawthorne Street,
of the Clean Air Act, EPA is proposing
San Francisco, CA 94105–3901.
to redesignate from ‘‘unclassifiable’’ to
Instructions: All comments will be
‘‘nonattainment’’ an area generally
included in the public docket without
covering the western half of Pinal
change and may be made available
County, Arizona, for the 1987 national
online at https://www.regulations.gov,
ambient air quality standard for
particles with an aerodynamic diameter including any personal information
provided, unless the comment includes
less than or equal to a nominal 10
Confidential Business Information (CBI)
micrometers (PM10), and therefore also
or other information whose disclosure is
proposing to revise the boundaries of
the existing ‘‘rest of state’’ unclassifiable restricted by statute. Information that
you consider CBI or otherwise protected
area. EPA’s proposal to establish this
should be clearly identified as such and
new PM10 nonattainment area, referred
to as ‘‘West Pinal,’’ is based on numerous should not be submitted through https://
recorded violations of the PM10 standard www.regulations.gov or e-mail. https://
www.regulations.gov is an ‘‘anonymous
at various monitoring sites within the
access’’ system, and EPA will not know
county. EPA’s proposed boundaries
your identity or contact information
would encompass all land
unless you provide it in the body of
geographically located within Pinal
your comment. If you send e-mail
County west of the north-south line
directly to EPA, your e-mail address
defined by the boundary between
will be automatically captured and
Townships 10E and 11E, but excluding
included as part of the public comment.
the main reservation of the Tohono
If EPA cannot read your comment due
O’odham Nation (TON) and excluding
to technical difficulties and cannot
the Apache Junction portion of the
contact you for clarification, EPA may
existing Phoenix PM10 nonattainment
not be able to consider your comment.
area. San Carlos Apache lands, which
Docket: The index to the docket for
are located in the eastern quarter of the
this action is available electronically at
county, would be excluded from the
proposed nonattainment area along with https://www.regulations.gov and in hard
the rest of the eastern half of the county. copy at EPA Region IX, 75 Hawthorne
Street, San Francisco, California. While
If finalized as proposed, the new ‘‘West
all documents in the docket are listed in
Pinal’’ PM10 nonattainment area would
be classified as ‘‘moderate’’ by operation the index, some information may be
publicly available only at the hard copy
of law. The effect of this action would
be to establish and delineate a new PM10 location (e.g., copyrighted material), and
nonattainment area within Pinal County some may not be publicly available in
either location (e.g., CBI). To inspect the
and thereby to impose certain planning
hard copy materials, please schedule an
requirements on the State of Arizona to
appointment during normal business
reduce PM10 concentrations within this
hours with the contact listed in the FOR
area, including, but not limited to, the
FURTHER INFORMATION CONTACT section.
requirement to submit, within 18
FOR FURTHER INFORMATION CONTACT:
months of redesignation, a revision to
Ginger Vagenas, EPA Region IX, (415)
the Arizona state implementation plan
that provides for attainment of the PM10 972–3964, vagenas.ginger@epa.gov.
standard as expeditiously as practicable SUPPLEMENTARY INFORMATION:
but no later than the end of the sixth
Throughout this document, ‘‘we,’’ ‘‘us’’
calendar year after redesignation. Lastly, and ‘‘our’’ refer to EPA.
EPA is deferring action on the status of
Table of Contents
certain tribal lands located within this
area, including the tribal lands of the
I. Background
Ak-Chin Indian Community and the
II. EPA’s Decision to Address PM10
Gila River Indian Community, as well as
Violations Monitored in Pinal County
TON’s Florence Village and San Lucy
Through Redesignation
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III. State of Arizona’s Recommendation for
Boundaries for New Nonattainment Area
IV. EPA’s Review of the State’s
Recommendation and Rationale for
Proposed Boundaries
V. EPA’s Review of Recommendations From
Affected Indian Tribes
VI. Proposed Action and Request for Public
Comment
VII. Statutory and Executive Order Reviews
I. Background
On July 1, 1987, EPA revised the
national ambient air quality standards
(NAAQS or ‘‘standards’’) for particulate
matter (52 FR 24634), replacing total
suspended particulates as the indicator
for particulate matter with a new
indicator called PM10 that includes only
those particles with an aerodynamic
diameter less than or equal to a nominal
10 micrometers.1 In order to attain the
NAAQS for 24-hour PM10, an air quality
monitor cannot measure levels of PM10
greater than 150 micrograms per cubic
meter (μg/m3) more than once per year
on average over a consecutive three-year
period. The rate of expected
exceedances, therefore, indicates
whether a monitor attains the air quality
standard.
Most of Pinal County, Arizona,
including the area that is the subject of
today’s action, was included in the ‘‘rest
of state’’ area, which was designated
‘‘unclassifiable’’ for PM10 by operation of
law upon enactment of the 1990
amendments to the Clean Air Act (CAA
or ‘‘Act’’).2 See section 107(d)(4)(B)(iii).
The PM10 designations established by
operation of law under the CAA, as
amended in 1990, are known as ‘‘initial’’
designations. The CAA grants EPA the
authority to change the designation of,
or ‘‘redesignate,’’ such areas in light of
changes in circumstances. More
specifically, CAA section 107(d)(3)
authorizes EPA to revise the designation
of areas (or portions thereof) on the
1 The 1987 PM
10 standard included a 24-hour
(150 micrograms per cubic meter (μg/m3)) and an
annual standard (50 μg/m3). In 2006, EPA revoked
the annual standard. See 71 FR 61144 (October 17,
2006) and 40 CFR 50.6.
2 While most of Pinal County was designated
‘‘unclassifiable,’’ two PM10 planning areas that
extend into Pinal County were designated under the
CAA, as amended in 1990, as ‘‘nonattainment:’’ The
Phoenix planning area, which includes the Apache
Junction area within Pinal County; and the Hayden/
Miami planning area, which includes the
northeastern portion of the county. See 56 FR 11101
(March 15, 1991); 56 FR 56694 (November 6, 1991);
and 57 FR 56762 (November 30, 1992). In 2007, we
approved a redesignation request by the State of
Arizona to split the Hayden/Miami PM10
nonattainment area into two separate PM10
nonattainment areas. See 72 FR 14422 (March 28,
2007). Today’s proposed action would not affect
these pre-existing PM10 nonattainment areas. EPA
codifies area designations in 40 CFR part 81. The
area designations for the State of Arizona are
codified at 40 CFR 81.303.
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basis of air quality data, planning and
control considerations, or any other airquality-related considerations that EPA
deems appropriate. Pursuant to CAA
section 107(d)(3), EPA in the past has
redesignated certain areas in Arizona to
nonattainment for the PM10 NAAQS,
including the Payson and Bullhead City
areas. See 56 FR 16274 (April 22, 1991);
and 58 FR 67334 (December 21, 1993).
II. EPA’s Decision to Address PM10
Violations Monitored in Pinal County
Through Redesignation
As noted above, EPA has the authority
under CAA section 107(d)(3) to
redesignate areas (or portions thereof)
on the basis of air quality data, planning
and control considerations, or any other
air-quality-related considerations. Last
year, under CAA section 107(d)(3)(A),
EPA notified the Governor of Arizona
and tribal leaders of the four Indian
Tribes (whose Indian country is located
entirely, or in part, within Pinal County)
that the designation for Pinal County,
and any nearby areas that may be
contributing to the monitored violations
in Pinal County, should be revised. Our
decision to initiate the redesignation
process stemmed from review of 2006–
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2008 ambient PM10 monitoring data
from PM10 monitoring stations within
the county that showed widespread,
frequent, and in some instances, severe,
violations of the PM10 standard.3
Table 1, below, presents a summary of
the latest available quality-assured PM10
monitoring data (2007–2009). A map
showing the location of the monitors is
included in our Technical Support
Document (TSD), contained in the
docket for this rulemaking.
TABLE 1—PINAL COUNTY—PM10 AIR QUALITY MONITORING DATA, 2007–2009
Site name
AQS*
ID
Apache Junction*** ..........................................................................................................................................
Casa Grande ...................................................................................................................................................
04–021–3002–1
04–021–0001–1
04–021–0001–3
04–021–3009–3
04–021–3004–1
04–021–3013–1
04–021–3013–3
04–021–3014–1
04–021–3006–1
04–021–3007–1
04–021–3010–3
04–021–3011–1
04–021–3011–2
04–021–3011–3
04–021–3012–1
04–021–3008–1
04–021–3008–3
04–021–7004–1
04–021–7004–2
Combs School (Queen Creek) ........................................................................................................................
Coolidge ...........................................................................................................................................................
Cowtown (southeast of Maricopa) ...................................................................................................................
Eloy ..................................................................................................................................................................
Mammoth .........................................................................................................................................................
Marana (Pinal Air Park) ...................................................................................................................................
Maricopa ..........................................................................................................................................................
Pinal County Housing/PCH (approx. 11 miles east of Casa Grande) ............................................................
Riverside (Kearny) ...........................................................................................................................................
Stanfield (approx. 15 miles west of Casa Grande) .........................................................................................
Bapchule (Gila River Indian Community monitors) .........................................................................................
PM10
Expected
exceedances**
2007–2009
0
0
4.7
17.6
2
112.9
139.8
0
0
0
12.6
6.5
5.9
15.6
0
16.4
17.8
6.6
7.9
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*AQS (Air Quality System) is an EPA database of ambient air quality.
**The 24-hour PM10 standard is met when the 3-year average of the expected exceedances is equal to or less than one.
***The Apache Junction site is located in the existing Phoenix PM10 nonattainment area.
As shown in Table 1, the data from
2007–2009 reveal violations at the PM10
monitors located in Queen Creek, Casa
Grande, Coolidge, Cowtown (which is
southeast of Maricopa), Maricopa,
Stanfield, at the Pinal County Housing
Complex (which is east of Casa Grande,
roughly half-way between Coolidge and
Eloy), and within the Gila River Indian
Reservation. Expected annual
exceedances (of the 150 μg/m3 24-hour
standard) at these monitoring sites range
from two (at Coolidge) to more than 100
(at Cowtown). (For the purposes of
comparison, the NAAQS is met when
the 3-year average of the expected
exceedances is equal to or less than
one.) Maximum 24-hour concentrations
measured at a number of these sites
(such as Cowtown, Maricopa and
Stanfield) can be more than two to three
times the level of the standard. In light
of the widespread, frequent, and severe
violations of the PM10 standard
monitored at various monitoring sites in
Pinal County, EPA continues to believe
that the SIP planning and control
requirements that are triggered by
redesignation of an area to
nonattainment for the PM10 NAAQS
would be the most appropriate means to
ensure that this air quality problem is
remedied.
Section III of this document describes
the State of Arizona’s recommendation
with respect to the boundaries of this
new PM10 nonattainment area, and
section IV of this document summarizes
EPA’s review of the State’s
recommendation and rationale for EPA’s
proposed boundaries. Section V
describes the Indian Tribes’
recommendations and our
corresponding responses. Section VI
describes our proposed action and the
corresponding CAA planning
requirements that would thereby be
triggered.
3 In a letter dated October 14, 2009, EPA notified
the State of Arizona that the PM10 designation in
Pinal County should be revised. EPA notified the
tribal leaders of the Ak-Chin Indian Community,
Gila River Indian Community, San Carlos Apache
Tribe, and Tohono O’odham Nation by letters dated
December 30, 2009.
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III. State of Arizona’s Recommendation
for Boundaries for New Nonattainment
Area
Pursuant to section 107(d)(3)(B) of the
Act, the Governor of Arizona responded
to EPA’s October 14, 2009 notification
that the PM10 designation of Pinal
County, and any nearby areas that may
be contributing to violations in Pinal
County, should be revised. The
Governor responded in a letter dated
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March 23, 2010 in which the Governor
recommended a partial-county
nonattainment area.4
The boundaries of the prospective
PM10 nonattainment area recommended
by the Governor of Arizona encompass
a portion of central and western Pinal
County, and form an area that resembles
a backwards ‘‘L.’’ 5 See figure 2 of EPA’s
TSD for a map of both the State’s
recommended boundaries as well as
EPA’s proposed boundaries. The staterecommended area includes all or most
of the cities of Maricopa, Coolidge, Casa
Grande and the Pinal County portion of
the town of Queen Creek, as well as the
western-most portion of the town of
Florence and the northern-most portion
of the city of Eloy. It includes an area
that at its western-most boundary
includes nearly all of the City of
Maricopa. The southern boundary is
defined by a line that coincides
approximately with Interstate 8. The
area continues to the east for
approximately 35 miles where it
extends to the north, including portions
of Florence and Coolidge, and the Pinal
County portion of Queen Creek, and
terminates just south of Apache
Junction. The eastern boundary is
defined by the north-south line between
Townships 8E and 9E. The northern
boundary follows the county line south
from the Apache Junction area and then
follows the boundary of the Gila River
Indian Reservation to close back around
to the recommended western boundary.
See the Governor’s March 23, 2010 letter
for the legal description of the State’s
recommended boundaries by township
and range and for an enclosed map
illustrating this area.
In support of the Governor’s
recommendation, on March 26, 2010,
the Arizona Department of
Environmental Quality (ADEQ)
submitted to EPA a technical report
entitled, ‘‘Arizona Air Quality
Designations, Technical Support
Document, Boundary Recommendation
for the Pinal County 24-hour PM10
Nonattainment Area (March 15, 2010),’’
(herein referred to as ADEQ’s ‘‘technical
report’’). ADEQ’s technical report
compiles and evaluates information
addressing nine factors 6 derived from
4 Letter from Jan Brewer, Governor of Arizona, to
Jared Blumenfeld, Regional Administrator, EPA
Region IX, dated March 23, 2010.
5 The Governor explicitly excludes Indian
country, which is appropriate given that the State
of Arizona is not authorized to administer programs
under the CAA in the affected Indian country. The
‘‘backwards L’’ shape of the recommended area is
partly explained by this exclusion because the
recommended area partially surrounds Indian
country.
6 The nine factors considered in ADEQ’s technical
report are air quality data, emissions data,
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and discussed in EPA guidance on
designation criteria; see citation on page
2 of ADEQ’s technical report to
Memorandum from Robert J. Meyers,
EPA Acting Assistant Administrator,
‘‘Area Designations for the Revised 24Hour Fine Particle National Ambient
Air Quality Standard,’’ dated June 8,
2007.
ADEQ points to a number of elements
that it believes support the
recommended boundaries. Specifically,
ADEQ claims that its recommended area
would include: all of the violating
monitors; the majority of PM10
emissions generated within the county;
the vast majority of the county’s
population; the rapidly growing
urbanized and developed areas, hightraffic Interstate corridors and areas
with the highest employment densities;
the significant growth areas along
Interstates 8 and 10; and the agricultural
basin where stagnation conditions are
known to impact PM10 concentrations.
ADEQ also believes that its
recommended redesignation would
maintain jurisdictional cohesiveness. To
buttress its recommended exclusion of
eastern Pinal County from the new
nonattainment area, ADEQ compares
these factors as they apply to western
Pinal County with those for eastern
Pinal County. ADEQ asserts that in
contrast to the western portion of Pinal
County, the eastern portion has no
violating monitors, contains few
emissions sources (other than certain
major sources that are already included
in an existing PM10 nonattainment area),
is largely undeveloped and has limited
growth potential. As set forth below in
more detail, while EPA believes this
characterization applies to the eastern
half of Pinal County, EPA also believes
that the western portion that should be
redesignated is far more extensive than
the State’s recommendation.
IV. EPA’s Review of the State’s
Recommendation and Rationale for
Proposed Boundaries
CAA section 107(d)(1)(A) generally
defines a nonattainment area as any area
that does not meet, or that contributes
to ambient air quality in a nearby area
that does not meet, the national primary
or secondary ambient air quality
standard for the relevant pollutant.
Thus, in reviewing the State’s
recommended boundaries, EPA has
considered not only areas where
violations of the relevant NAAQS have
population density and degree of urbanization,
traffic and commuting patterns, growth rates and
patterns, meteorology, geography/topography,
jurisdictional boundaries, and level of control of
emission sources.
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been monitored, but also that contribute
to such violations.
EPA guidance 7 provides for the use of
‘‘a qualitative analysis of the area of
representativeness of the monitoring
station, together with the consideration
of terrain, meteorology, and sources of
emissions * * *’’ in defining
nonattainment area boundaries for
PM10. Consistent with that guidance,
EPA generally recommends that States
identify nonattainment area boundaries
based on the weight of evidence of the
following factors and other relevant
information:
—Air quality data;
—Pollutant emissions;
—Population density and degree of
urbanization;
—Traffic and commuting patterns;
—Growth;
—Meteorology;
—Geography and topography;
—Jurisdictional boundaries; and
—Level of control of emissions sources.
See, e.g., Memorandum from Robert J.
Meyers, EPA Acting Assistant
Administrator, ‘‘Area Designations for
the Revised 24-Hour Fine Particle
National Ambient Air Quality
Standard,’’ dated June 8, 2007. EPA also
looks to the same kinds of factors in the
context of redesignations. See, e.g.,
EPA’s proposed (73 FR 22307, at 22308–
22310, April 25, 2008) and final
approval (73 FR 66759, November 12,
2008) of a state request to redesignate
the San Joaquin Valley PM10
nonattainment area. In addition, CAA
section 107(d)(3)(A) allows EPA, in
redesignating areas to nonattainment, to
take into consideration ‘‘any other airquality-related considerations.’’ In its
technical report, ADEQ refers to the
nine factors in developing the State’s
recommended boundaries for the new
PM10 nonattainment area. In the
following paragraphs, we review and
evaluate ADEQ’s nine factor analysis.
Air Quality Data. ADEQ’s technical
report summarizes 2006–2008 PM10
monitoring data from 12 monitoring
sites within Pinal County. Most of the
monitoring sites are located in the west
central portion of the county (Maricopa,
Cowtown, Stanfield, Casa Grande, Pinal
County Housing Complex, and
Coolidge). Two are located in the
southern portion (Eloy and Pinal Air
Park); two are located in the northern
portion [Apache Junction and Combs
School (located in Queen Creek)]; and
two are located in the far eastern portion
of the county (Riverside and Mammoth).
The Apache Junction and Riverside
7 PM
10 SIP Development Guideline, EPA–450/2–
86–001, June 1987.
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monitoring sites are located within
existing PM10 nonattainment areas.
Based on 2006–2008 data, ADEQ
finds six of the monitoring sites to be in
violation of the PM10 NAAQS. EPA has
updated this monitoring information by
reviewing 2007–2009 data. Although we
find that these data are largely
consistent with the data presented by
ADEQ, the more recent data set shows
seven violating monitors (not counting
the PM10 monitoring site on the Gila
River Indian Reservation) rather than
six. Coolidge is the additional
monitoring site that is newly violating
based on the more recent data set. In its
technical report, ADEQ notes that its
proposed boundaries include the
locations of all of the violating monitors
within Pinal County. While we agree
that Arizona’s proposed boundaries do
in fact include all of the violating
monitors (i.e., other than the monitoring
site located within the Gila River Indian
Reservation and those located within
existing PM10 nonattainment areas), we
disagree with ADEQ’s contention that
its proposed boundaries include all
areas that do not experience violations
but nonetheless contribute to the
violations that are recorded at the
monitoring sites based on an evaluation
of the other eight factors as discussed in
the following paragraphs.
Emissions Data. ADEQ developed an
annual emissions inventory of PM10
sources in the county for the year 2007
for the purpose of defining a boundary
for the new nonattainment area. ADEQ’s
inventory relies on a number of different
data sources, assumptions, and methods
(including EPA’s MOBILE model and
compilation of emissions factors (AP–
42)) to calculate annual PM10 emissions
in the county. ADEQ’s inventory points
to fugitive emissions from vehicular
traffic on paved and unpaved roads as
the single largest source category,
followed in importance by agricultural
sources (including concentrated animal
feeding operations), industrial sources,
and construction. ADEQ’s technical
report includes maps that show the
relative distribution of emissions
generated within the county using 4kilometer grid cells. See in particular
the following maps in the State’s
technical report: Figure 3–3 on page 8
(all PM10 sources) and figure 3–4 on
page 11 (paved and unpaved on-road
sources). The maps show that PM10
emissions in the county are
concentrated in the western half of the
county, with the highest emissions
densities in the west central portion of
the county. In contrast, the eastern half
of the county (outside of the existing
nonattainment areas) is characterized
predominantly by the lowest category of
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emissions densities (i.e., 0 to 20 tons per
year per 4-kilometer grid). See page 8 of
ADEQ’s technical report.
While EPA finds that the PM10
emissions inventory for Pinal County
and ADEQ’s corresponding maps are
helpful in defining the boundaries of the
new nonattainment area, we do not
believe that they justify ADEQ’s
conclusions about its recommended
boundaries. ADEQ claims that the
emissions inventory and maps
demonstrate that sources in the eastern
and southern regions of the county do
not ‘‘significantly contribute’’ to
violations in the other regions of the
county. See page ES–3 of ADEQ’s
technical report. EPA notes, however,
that CAA section 107(d)(1)(A) defines a
nonattainment area as one that does not
meet, or that ‘‘contributes to’’ ambient
air quality in a nearby area that does not
meet the NAAQS. The definition of
nonattainment areas is not limited to
areas that, in ADEQ’s words,
‘‘significantly’’ contribute to a violating
area. Moreover, ADEQ’s maps show that
areas immediately to the east and south
of the recommended area (but still
within the western half of the county)
include the same types of emissions
sources, with similar emissions
densities, as those that predominate
within the recommended area. For
example, figure 3–3 (page 8 of State’s
technical report) shows emissions
densities similar to those estimated
within the State’s recommended
boundaries to the east in Coolidge and
Florence, as well as south to Eloy. In
addition, figures 3–4, 3–7, and 3–10 (on
pages 11, 14, and 17, respectively, of the
State’s technical report) illustrate the
locations of unpaved roads (with
average daily traffic volumes greater
than 100) and show that higher relative
concentrations of PM10 emissions from
such sources as vehicle entrainment of
dust over paved and unpaved roads,
tilling and harvesting, and concentrated
animal feeding operations (CAFOs)
extend to central, and south central
Pinal County. Thus, the emissions
inventory data and related maps do not
support the State’s recommended
boundaries but rather argue for a larger
nonattainment area consisting of the
western half of the county.
In contrast, EPA’s proposed
boundaries include all of the areas for
which emissions data show relatively
higher PM10 emissions from the types of
sources contributing the most to the
overall PM10 emissions inventory. For
instance, based on the information
sources described above in the State’s
technical report, EPA’s proposed
boundaries include the areas of
relatively higher emissions densities in
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and around Coolidge, Florence, and
Eloy that reflect the same types of PM10generating activities (vehicle
entrainment of dust over paved and
unpaved roads, tilling and harvesting,
and CAFOs) as found within the smaller
nonattainment area boundaries
recommended by the State.
Population density, degree of
urbanization, growth rate and patterns.
This factor reflects EPA’s belief that the
size, density, and location of population
can be indicative of emissions activity
that contributes to violations of the
PM10 NAAQS in an area. ADEQ’s
technical report presents population
growth and density figures for
municipalities in Pinal County. The
data show that Pinal County has grown
dramatically over the past decade
(nearly doubling from a population of
approximately 180,000 in 2000 to nearly
360,000 in 2008). EPA independently
collected and reviewed populationrelated information and notes that the
populations of the largest cities and
towns in the western half of the county,
such as (the city of) Maricopa (2008
population of approximately 46,000),
Casa Grande (41,000), Apache Junction
(33,000), Florence (21,000), and Eloy
(13,000), contrast sharply with much
smaller populations in the largest cities
and towns in the eastern half of the
county, including Superior (3,000),
Kearny (3,000), and Mammoth (3,000).
See page 14 of EPA’s TSD.
ADEQ also submitted maps showing
population densities both under current
conditions and projections for the year
2030 when the population of Pinal
County is anticipated to exceed
1,000,000. Under existing conditions,
higher population densities are found in
the west central portion of the county,
but there are also population centers in
the northern (Apache Junction and
Queen Creek) and southern portions
(Eloy) of the county. ADEQ’s maps show
that future growth is expected to be
concentrated in the Interstate 8 and 10
corridors, which extend through the
west central and southern portions of
the county, although a certain amount of
growth is also expected in the Falcon
Valley area farther to the east.
In its technical report, ADEQ
concludes that the eastern and southern
portions of the county are largely
undeveloped and have very low
population densities, and finds that this
information provides support for the
State’s recommended boundaries.
However, like the emissions data
discussed above, we believe that the
data do not justify the restricted nature
of the State’s recommended boundaries,
which exclude much of the western half
of the County. Specifically, EPA
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believes that the State’s recommended
exclusion of areas in the eastern and
southern sections of the western half of
the county is contradicted by evidence
showing that land use development in
Pinal County extends further east and
south than the State’s recommended
boundaries. For example, the State’s
recommended boundaries fail to include
the agricultural and more urbanized
uses in and around Eloy and the future
growth areas along the two Interstate
corridors. See figures 3–13 and 3–14
from the State’s technical report. In
contrast, EPA’s proposed boundaries
would include all of the western half of
Pinal County (excluding TON’s main
reservation and the Apache Junction
portion of the Phoenix PM10
nonattainment area) and thereby would
include the areas with relatively higher
population densities and most of the
areas where significant levels of growth
are expected.
Traffic and commuting patterns. This
factor considers the commuting patterns
of residents in, and commuters to, Pinal
County. More specifically, this factor
considers the number of commuters in
each surrounding county who drive to
Pinal County, the percent of total
commuters in each county who
commute to Pinal County, the percent of
total commuters in each county who
commute into the statistical area in
which Pinal County is located, as well
as the total vehicle miles traveled (VMT)
for each county.
ADEQ’s technical report (page 23)
presents statistics from the 2000 census
quantifying the number of commuters
from each county within the State of
Arizona to jobs within Pinal County,
and the number of commuters residing
in Pinal County to jobs in Maricopa and
Pima counties. The data from 2000
indicate that approximately 10,000
commuters, or roughly 20% of total
commuters to jobs within Pinal County,
reside outside of Pinal County.
Conversely, approximately 36,000
(roughly 80%) of commuters travel
solely within Pinal County. Almost 80%
of the out-of-county commuters reside
to the north in Maricopa County, and
nearly all remaining out-of-county
commuters commuting to Pinal County
reside to the south in Pima County.
Moreover, nearly 40% of commuters
residing in Pinal County work in either
Maricopa or Pima counties, whereas
60% of commuters residing in Pinal
County also work in Pinal County.
EPA independently reviewed these
same data and observed that the
principal route for traffic through Pinal
County (serving in-county as well as
out-of-county commuters) is Interstate
10, which bisects the western half of the
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county and connects metropolitan
Phoenix (largely in Maricopa County) to
the north with metropolitan Tucson (in
Pima County) to the south. ADEQ cites
traffic and commuting patterns as a
factor supporting the exclusion of the
eastern half of the county from the new
nonattainment area. While EPA agrees
that it is reasonable to distinguish
between the eastern and western halves
of the county, EPA believes that the data
indicate that the entire western half of
the county, and not a small portion of
it, as the State recommends, should be
redesignated to nonattainment. Thus,
EPA finds that traffic and commuting
patterns do not make a case for the
state’s recommendation, but rather lend
support to the creation of a larger
nonattainment area generally
encompassing the western half of the
County. See figure 3–17 from the State’s
technical report, which shows much
higher employment densities
projections for year 2030 in the western
half of the county than those in the
eastern half but which also show higher
employment densities east and south of
the State’s recommended boundaries
(but still within the western half of the
county).
Meteorology. Generally, the analysis
of meteorology looks to wind data for
evidence that emissions originating
from areas in certain locations relative
to violating monitors may be more
prone to contribute than emissions
originating from sources located
elsewhere. ADEQ’s technical report
describes the dynamics responsible for
region-wide weather patterns and the
associated winds blowing across
Arizona, as well as the frequent
occurrence of ‘‘drainage’’ winds, which
occur when large-scale weather
influences wane. ADEQ describes how
steep pressure gradients result from
strong high pressure building over the
western United States and low pressure
to the east. As the high pressure builds,
a steep pressure differential is created
that causes strong winds over Arizona to
entrain and transport dust from incounty and out-of-county sources. These
can cause elevated PM10 concentrations.
ADEQ also notes however, that not all
exceedances of the PM10 standard are
wind-related and that stagnation
conditions in the fall and winter occur
when cold air and the absence of winds
trap ambient PM10 in the lower
atmosphere. ADEQ notes that the region
of the county most impacted by
stagnation conditions is the western
agricultural basin.
The State recommends including the
agricultural basin region of the county
where stagnation conditions are known
to impact PM10 concentrations. While
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we agree that the new nonattainment
area should include the agricultural
basin region where stagnation
conditions occur, we find that the
State’s recommended boundaries do not
in fact accomplish this. As shown on
page 14 of the ADEQ’s technical report,
the agricultural basin region of the
county, roughly defined based on tilling
and harvesting emissions within the
county, lies in the western half of the
county, and also extends south of
Interstate 10 towards the southern
county line. Moreover, as discussed in
the following paragraph, a review of
available wind data supports the
inclusion of areas to the south and east
of the violating monitors (i.e., beyond
the State’s recommended boundaries)
based on the prevalence of winds from
the southeast quadrant.
EPA has considered the information
provided by ADEQ but also reviewed
available wind data for Pinal County
and finds that winds are similar
throughout central and western Pinal
County in that the predominant wind
directions are from the southeast
quadrant. See figure 10 of EPA’s TSD.
(We note that winds blow out of the
north and northwest far less frequently,
making transport of PM10 from the
metropolitan Phoenix area unlikely
under most circumstances.) In this
instance, the predominance of southeast
winds support boundaries that extend
south and east of the violating monitors
because PM10 sources, including
agricultural activities and unpaved
roads, are found in those directions.
EPA’s recommended boundaries
encompass the types of sources that are
believed to cause or contribute to the
monitored violations and that are
located east and south of the violating
monitors, whereas the State’s
recommended boundaries largely
exclude these sources. See figure 2
(PM10 monitors, ADEQ’s recommended
nonattainment area boundary, and
EPA’s proposed nonattainment area
boundary), figure 4 (Pinal County
agriculture, cattle operations, and
unpaved roads), and figure 5 (ADEQ’s
map illustrating the distribution of
emissions in Pinal County) from EPA’s
TSD.
Lastly, EPA recognizes that high wind
events do occur in Pinal County, and
that some of these events may result in
monitored particulate matter
exceedances that qualify as caused by
exceptional events under EPA’s
exceptional events rule.8 However, as
8 On March 22, 2007, EPA adopted a final rule,
Treatment of Data Influenced by Exceptional
Events, to govern the review and handling of certain
air quality monitoring data for which the normal
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ADEQ itself acknowledges, even if EPA
were eventually to determine that all of
the exceedances that ADEQ has flagged
are caused by ‘‘exceptional events,’’ the
area would still clearly be in violation
of the PM10 NAAQS.
Geography/Topography. The
geography/topography factor evaluates
physical features of the land that might
have an effect on the airshed, and
therefore, on the distribution of
particulate matter over an area. In its
technical report, ADEQ describes the
topography of Pinal County in terms of
a broad basin, low in elevation (roughly
1,200 feet in elevation), surrounded on
all sides by mountain ranges. ADEQ
finds that topographic considerations
support the State’s inclusion of the
basin region of the county, which is
characterized by open-ended valleys
with few topographic barriers, within
the recommended boundaries.
Conversely, ADEQ finds that
topographic considerations support the
State’s exclusion from the
recommended boundaries of the eastern
portion of the county, which is
characterized by rough terrain and steep
mountain ranges reaching over 7,000
feet in elevation.
EPA too has considered topography
and generally agrees with ADEQ’s
description of the topography of Pinal
County. We believe that the various
mountain ranges found on each side of
the county inhibit transport of PM10
(which is largely crustal in
composition—see figure 6 of EPA’s
TSD) from outside the county to the
violating monitors within the county.
Within the county itself, we believe that
the mountains in the eastern quarter of
the county, which rise to approximately
6,000 feet near the eastern borders with
Gila and Graham counties, inhibit intracounty transport from sources located in
the eastern quarter to the violating
monitors. See figure 11 of EPA’s TSD.
(The portion of the San Carlos Apache
Reservation that lies within Pinal
County is located in the eastern quarter
of the county.)
However, the existence of the steep
mountain ranges in the eastern quarter
of the County does not justify ADEQ’s
recommendation to exclude from
redesignation a much larger section of
the western half of the County. EPA
believes that, taking other factors into
account, the western half of the County,
planning and regulatory processes are not
appropriate. Under the rule, EPA may exclude data
from use in determinations of National Ambient Air
Quality Standard (NAAQS) exceedances and
violations if a state demonstrates that an
‘‘exceptional event’’ caused the exceedances, and
satisfies other criteria set forth by the rule. See 72
FR 13560.
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located in the basin region that features
few topographic barriers, should be
redesignated to nonattainment. Indeed,
it is arguable that topography alone
would lend support to redesignating a
far larger area than EPA is proposing,
one that would encompass the entire
county, excepting only the eastern
quarter. However, EPA believes that
topography when evaluated in the
context of the various other factors,
supports redesignation of the western
half of the county, rather than the much
more restricted boundaries that ADEQ
suggests.
Jurisdictional Boundaries. The
analysis of jurisdictional boundaries
evaluates the planning and
organizational structure of an area to
determine if the implementation of
controls in a potential nonattainment
area can be carried out in a cohesive
manner. ADEQ’s technical report notes
the absence of any certified
metropolitan planning organization
(MPO) for Pinal County and the
exclusion of Indian country from the
State’s recommendation. As such,
ADEQ concludes that the State’s
recommended boundaries maintain
jurisdictional cohesiveness requiring no
new institutional arrangements for
accomplishing required tasks.
EPA also considered the planning and
organizational structure of the State of
Arizona and Pinal County (cities, towns,
and unincorporated areas), but also took
into account Indian country, to ensure
that the implementation of controls
within the prospective nonattainment
area could be carried out in a cohesive
manner. ADEQ exercises overall
jurisdiction over environmental
programs in the State of Arizona (i.e.,
excluding Indian country). Under state
law, ADEQ has the responsibility for
preparing air quality attainment and
maintenance plans in Pinal County.
With respect to permitting and
enforcement, the Pinal County Air
Quality Control District (AQCD or
‘‘District’’) has jurisdiction over most
types of stationary sources operating, or
proposing to locate, within Pinal
County, but state law retains ADEQ’s
statewide jurisdiction over certain types
of stationary sources (smelters,
refineries, coal-fired power plants, and
agricultural operations). Neither ADEQ
nor the District have jurisdiction within
Indian country.
In its technical report, ADEQ notes
that five cities and towns (Casa Grande,
Coolidge, Eloy, Florence, and City of
Maricopa), as well as a portion of a sixth
(Queen Creek) are located in central and
western Pinal County. ADEQ indicates
that the incorporated boundaries of
these municipalities have been taken
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into account in developing the
nonattainment area boundaries.
However, EPA’s review of the
incorporated boundaries of these
municipalities (see, e.g., figure 2 of
EPA’s TSD) shows that the State’s
recommended boundaries omit portions
of the City of Maricopa and Coolidge,
and most of Florence and Eloy. In
contrast, EPA’s proposed nonattainment
area boundaries encompass all of these
cities and towns, where most of the
county’s population resides. Inclusion
of entire cities and towns within the
nonattainment area boundaries would
facilitate attainment planning to the
extent that such local governments will
ultimately be relied upon for
development and/or implementation of
specific PM10 control measures.
Level of Control of Emission Sources.
The level of control factor looks at the
emissions controls currently
implemented in each area. As a general
matter, most existing and proposed
stationary sources within Pinal County
(excluding Indian country) are subject to
the generally applicable prohibitory
rules and permitting requirements
established by the Pinal County AQCD,
or, in the case of certain types of
stationary sources (smelters, refineries,
coal-fired power plants, and agricultural
operations), State prohibitory rules and
permitting requirements established by
ADEQ.
Pinal County AQCD has established
rules for dust abatement purposes that
apply within a subarea of Pinal County
established under state law (Arizona
Revised Statutes section 49–541) and
referred to as ‘‘Area A.’’ Within Pinal
County, ‘‘Area A’’ generally refers to an
area encompassing the Pinal County
portions of Apache Junction and Queen
Creek. Pinal County has also adopted a
number of ordinances that are also
intended to reduce dust generated
within ‘‘Area A.’’ These include
ordinances placing restrictions on
residential fireplaces, leaf blowers, open
burning, vehicle commute trips, and
vehicle idling. For one township located
within ‘‘Area A,’’ the township included
in the Phoenix Area PM10
nonattainment area (i.e., Township 1
north, range 8 east; referred to as
‘‘Apache Junction’’), Pinal County AQCD
has adopted further dust abatement
rules.9 The State’s recommended
boundaries include a portion, but not
all, of ‘‘Area A.’’ In contrast, EPA’s
proposed boundaries for the new
nonattainment area would encompass
9 The township referred to as Apache Junction
would be unaffected by our proposed action and
would remain part of the Phoenix planning area,
which is designated as a ‘‘serious’’ PM10
nonattainment area.
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all of ‘‘Area A,’’ thereby facilitating
review and modification of these
existing PM10 emissions controls within
the broader SIP attainment planning
context.
Conclusion. CAA section 107(d)(3)(C)
provides that after notifying the
Governor of State of its intent to
redesignate an area, EPA shall
promulgate the redesignation, if any, of
the area or portion thereof, submitted by
the Governor, ‘‘making such
modifications as EPA may deem
necessary. * * *’’ Pursuant to CAA
section 107(d)(3), we have reviewed the
State’s recommendation (dated March
23, 2010) and related technical report
(submitted on March 26, 2010).
Both EPA and the State agree that
sources outside of the county do not
contribute to PM10 violations at the
violating monitors within the county,
and that sources in the eastern half of
the county do not contribute to the
violating monitors (which are
concentrated in the central and western
portions of the county). But while EPA
and the State both use the nine-factor
analysis for evaluation of the
prospective nonattainment area
boundaries, we reach quite different
conclusions.
As explained above, and more fully in
EPA’s TSD, EPA does not believe that
the State’s recommended boundaries
encompass the full geographic area from
which emissions-generating activities
contribute to the monitored PM10
violations. More specifically, we believe
that the Governor’s recommended
boundaries, which cut through
municipalities and contiguous expanses
of agricultural fields, exclude sources
that have been identified as dominant
sources of PM10 and that are
contributing to elevated levels of PM10
at violating monitors.
We believe that our proposed
boundaries, which are defined as all
land geographically located within Pinal
County west of the north-south line
defined by the boundary between
Townships 10E and 11E, but excluding
TON’s main reservation and excluding
the existing Apache Junction portion of
the existing Phoenix PM10
nonattainment area, encompass the
areas in which PM10 violations are being
monitored, as well as the areas that
contribute to the monitored violations,
and that they are thus consistent with
the definition of nonattainment areas in
CAA section 107(d)(1)(A). Our
conclusion is based on EPA’s analysis of
the factors as set forth in the body of this
document and in further detail in the
TSD. In sum, we base our proposed
boundaries on the following
considerations: (1) Monitored violations
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occur in the west, central and northern
portions of the western half of the
county, not in the eastern half (i.e.,
outside of existing PM10 nonattainment
areas); (2) the emissions from
agricultural operations, feedlots, dairies,
and other cattle operations, as well as
roads, are concentrated in the western
half of the county; (3) population
densities are much greater in the
western half of the county than in the
eastern half and growth is expected to
be concentrated primarily along the
Interstate corridors that extend through
the western half of the county; (4)
Interstate 10, which connects Pinal
County with the employment centers in
metropolitan Phoenix and Tucson,
bisects the western half of Pinal County;
(5) predominant southeasterly winds
support inclusion of PM10 sources in
areas to the south and east of the
violating monitors; (6) the western half
of Pinal County encompasses the
incorporated boundaries of all of the
cities in Pinal County (Apache Junction,
Casa Grande, Coolidge, Eloy, Maricopa),
as well as the larger towns (Florence
and Queen Creek) thereby potentially
facilitating implementation of future
control measures; and (7) dust
abatement measures already in effect in
‘‘Area A’’ (within Pinal County) can
readily be applied, as necessary and
appropriate, throughout the other
portions of the western half of Pinal
County. A map comparing the State’s
recommended boundaries to EPA’s
proposed boundaries is included as
figure 2 in our TSD.
EPA therefore deems it necessary and
appropriate to propose boundaries that
differ from the State’s recommended
boundaries and that we believe better
satisfy air quality data, planning, control
and other air-quality-related
considerations. CAA Section 107(d)(3).
Under CAA section 107(d)(3)(C), EPA
must notify the State whenever EPA
intends to modify State
recommendations concerning
boundaries for areas to be redesignated,
at least 60 days prior to EPA
promulgation of final redesignations.
EPA intends to notify the State of
Arizona of our proposed action soon
after this notice is signed.
V. EPA’s Review of Recommendations
From Affected Indian Tribes
Ak-Chin Indian Community. The AkChin Indian Community is located in
western Pinal County, and is included
in the existing ‘‘rest of state’’
unclassifiable area for PM10. The AkChin Indian Community does not
operate a PM10 monitoring site, but lies
in proximity to several PM10 monitoring
sites that do monitor violations of the
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PM10 NAAQS (e.g., the Maricopa and
Cowtown sites). In a letter dated
September 2, 2010 the Ak-Chin Indian
Community responded to EPA’s
December 30, 2009 letter concerning the
PM10 designation of Pinal County with
a recommendation that the Ak-Chin
lands be designated attainment/
unclassifiable. We have offered formal
consultation to the Ak-Chin Indian
Community and have decided to defer
action on redesignation of the Ak-Chin
Indian Community for PM10 to allow
time for formal consultation to occur
and for further consideration of this
issue as part of that process. If in the
future EPA decides to take action to
redesignate the Ak-Chin Indian
Community, the Agency will do so in a
separate rulemaking.
Gila River Indian Community. The
Gila River Indian Community (GRIC) is
a community located on 374,000 acres
in south central Arizona. Approximately
one-third of GRIC lies within Maricopa
County and two-thirds lies within Pinal
County. The Maricopa County portion
of GRIC is included in the Phoenix Area
PM10 nonattainment area. The Pinal
County portion of GRIC is included in
the existing ‘‘rest of state’’ unclassifiable
area for PM10. GRIC operates a PM10
monitoring site in the Pinal County
portion of its lands and GRIC’s monitor
has recorded a number of PM10
exceedances. See table 1 above in this
document. However, GRIC has flagged a
significant number of these exceedances
as caused by ‘‘exceptional events’’ under
EPA’s exceptional event rule (50 CFR
50.14), and EPA has not yet taken action
to determine whether any of these data
should be excluded on that basis from
consideration in a redesignation action.
In October 2009, EPA approved GRIC’s
application for treatment in the same
manner as a state for the purposes of
CAA section 107(d) air quality
designations. More recently, we
proposed approval of GRIC’s submitted
tribal implementation plan. See 75 FR
48880, August 12, 2010.
As noted above, on December 30,
2009, EPA notified GRIC that the PM10
designation for Pinal County should be
revised. GRIC first indicated orally, and
later confirmed in a letter dated May 27,
2010, that the community would not be
making a recommendation for PM10
until formal consultation is conducted.
By letter dated April 30, 2010, EPA
responded to GRIC’s oral request with
an offer of formal consultation. As with
the Ak-Chin Indian Community, we
have decided to defer action on a
decision whether to redesignate GRIC to
allow time for formal consultation to
occur and for further consideration of
this issue as part of that process. In
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addition, the deferral for GRIC will
provide EPA with the time necessary to
address the exceptional events issues. If
in the future EPA decides to undertake
redesignation of the Pinal County
portion of the Gila River Indian
Community, the Agency will do so in a
separate rulemaking.
San Carlos Apache Tribe. The San
Carlos Apache Reservation extends over
a portion of eastern Pinal County, as
well as portions of Gila and Graham
counties. A section of the Pinal County
portion of the San Carlos Apache
Reservation lies in the existing Hayden
PM10 nonattainment area. The rest of the
Pinal County portion of the reservation
is located within the ‘‘rest of state’’
unclassifiable area for PM10. The San
Carlos Apache Tribe did not respond to
EPA’s December 30, 2009 letter
concerning the PM10 designation in
Pinal County.
For the reasons discussed in section
IV of this document, we believe that
emissions sources in the eastern half of
Pinal County do not contribute to
violations monitored in the western half
of the county, and thus are proposing
only that the western half of the county
(excluding TON’s main reservation and
the Apache Junction portion of the
existing Phoenix PM10 nonattainment
area) be redesignated to nonattainment.
Given that the San Carlos Tribe’s Indian
country extends only into far eastern
Pinal County, we propose to retain the
Tribe’s current designations for the
PM10 standard (i.e., a portion remains in
the existing Hayden PM10
nonattainment area, and a portion
remains in the existing ‘‘rest of state’’
unclassifiable area).
Tohono O’odham Nation. The
Tohono O’odham Nation (TON) extends
over portions of Pima, Maricopa and
Pinal counties. TON’s main reservation
covers much of southwestern Pinal
County and extends over portions of
Pima and Maricopa counties. TON’s
lands also include a small area
(approximately 25 acres), known as
Florence Village, which is located
approximately two miles west of the
town of Florence in central Pinal
County, and a 3,200-acre parcel east of
the main reservation called San Lucy
Farm. With the exception of a small
portion of TON included within the
existing Rillito PM10 nonattainment area
(which is located in Pima County), TON
is included in the ‘‘rest of state’’
unclassifiable area for PM10.
In a letter dated February 11, 2010,
TON responded to EPA’s December 30,
2009 letter concerning the PM10
designation in Pinal County with a
recommendation that the TON land
within Pinal County be designated
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all of the area recommended by the
State of Arizona, but would extend
further to the east and south, and to a
lesser degree, to the north and west.
EPA’s proposed boundaries would
encompass all land geographically
located within Pinal County west of the
north-south line defined by the
boundary between Townships 10E and
11E, but excluding TON’s main
reservation and excluding the Apache
Junction portion of the existing Phoenix
PM10 nonattainment area. If finalized as
proposed, the new ‘‘West Pinal’’ PM10
nonattainment area would be classified
as ‘‘moderate’’ by operation of law. See
figure 2 of EPA’s TSD for a map
showing EPA’s proposed boundaries.
We believe that our proposed
boundaries as described above
encompass the areas in which PM10
violations are being monitored, as well
as the areas that contributes to the
monitored violations, and that they are
thus consistent with the definition of
nonattainment areas in CAA section
107(d)(1)(A). Our conclusion is based on
EPA’s analysis of the factors as set forth
in the body of this document and in
further detail in the TSD. We find
support for our proposed boundaries
based on the following considerations:
(1) Monitored violations occur in the
west, central and northern portions of
the western half of the county, not in
the eastern half (i.e., outside of existing
PM10 nonattainment areas); (2) the
emissions from agricultural operations,
feedlots, dairies, and other cattle
operations, as well as roads, are
concentrated in the western half of the
county; (3) population densities are
much greater in the western half of the
VI. Proposed Action and Request for
county than in the eastern half and
Public Comment
growth is expected to be concentrated
primarily along the Interstate corridors
Pursuant to section 107(d)(3) of the
that extend through the western half of
Clean Air Act and based on our
the county; (4) Interstate 10, which
evaluation of air quality data, planning,
connects Pinal County with the
control and other air-quality-related
information and considerations, and our employment centers in metropolitan
Phoenix and Tucson, bisects the
review of the Governor’s
western half of Pinal County; (5)
recommendation, EPA is proposing to
predominant southeasterly winds
redesignate from ‘‘unclassifiable’’ to
support inclusion of PM10 sources in
‘‘nonattainment’’ an area generally
areas to the south and east of the
covering the western half of Pinal
violating monitors; (6) the western half
County, Arizona, for the 1987 PM10
of Pinal County encompasses the
NAAQS and therefore to revise the
boundaries of the existing ‘‘rest of state’’ incorporated boundaries of all of the
cities in Pinal County (Apache Junction,
unclassifiable area. EPA’s proposal to
Casa Grande, Coolidge, Eloy, Maricopa),
establish this new PM10 nonattainment
area, referred to as ‘‘West Pinal,’’ is based as well as the larger towns (Florence
and Queen Creek) thereby potentially
on numerous recorded violations of the
facilitating implementation of future
PM10 standard at various monitoring
sites within the county, and on the other control measures; and (7) dust
abatement measures already in effect in
grounds set forth in this document and
‘‘Area A’’ (within Pinal County) can
in the TSD.
readily be applied, as necessary and
EPA’s proposed boundaries for the
appropriate, throughout the other
nonattainment area would encompass
attainment/unclassifiable for PM10. With
respect to the main reservation in
southwestern Pinal County, we agree
with TON’s recommendation and are
proposing a nonattainment area with
boundaries that exclude TON’s main
reservation. We agree with TON’s
recommendation in this regard because
(1) the closest violating monitors
(Stanfield and Casa Grande) are located
in the midst of the county’s agricultural
basin, well north of TON’s main
reservation; (2) the types of emissions
sources believed to be responsible for
the PM10 violations, such as agricultural
operations, feedlots, and dairies (see
figure 4 of EPA’s TSD), as well as roads,
are largely absent from TON; (3) the
population density of TON is very low,
and is an order of magnitude less than
the average population density of Pinal
County (see table 5 of EPA’s TSD); and
(4) TON is a separate sovereign not
subject to state or county jurisdiction
thereby complicating planning and
implementation issues. We conclude
therefore that TON’s main reservation is
not contributing to the PM10 violations
monitored elsewhere in Pinal County
and propose to exclude TON from the
new nonattainment area. Under this
proposal, the designation of TON’s main
reservation would remain unchanged,
i.e., it would remain part of the ‘‘rest of
state’’ unclassifiable area for PM10.
As to Florence Village and San Lucy
Farm, EPA is deferring redesignation to
allow for further consultation with
TON. If in the future EPA decides to
take action to redesignate TON’s
Florence Village and San Lucy Farm,
the Agency will do so in a separate
rulemaking.
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portions of the western half of Pinal
County.
EPA has determined that activities
occurring on the main Tohono O’odham
Nation (TON) reservation are not
causing or contributing to violations
occurring in Pinal County and we are
therefore proposing to exclude the main
TON reservation from the new
nonattainment area. San Carlos Apache
lands, which are located in the eastern
quarter of the county, would be
excluded from the proposed
nonattainment area along with the rest
of the eastern half of the county. EPA is
deferring its decision regarding
redesignation of the Ak-Chin and Gila
River Indian Community lands, as well
as TON’s Florence Village and San Lucy
Farm, pending consideration of issues
unique to tribal lands, completion of
formal consultation with the tribal
governments, and (in the case of GRIC)
consideration of exceptional events
flags. The existing Phoenix PM10
nonattainment area (including the
Apache Junction portion of western
Pinal County) would be unaffected by
this action.
Areas redesignated as nonattainment,
as proposed herein, are subject to the
applicable requirements of part D, title
I of the Act and will be classified as
moderate by operation of law (see
section 188(a) of the Act). Within 18
months of the redesignation, the State is
required to submit to EPA an
implementation plan for the area
containing, among other things, the
following requirements: (1) Provisions
to assure that reasonably available
control measures (including reasonably
available control technology) are
implemented within 4 years of the
redesignation; (2) a permit program
meeting the requirements of section 173
governing the construction and
operation of new and modified major
stationary sources of PM10; (3)
quantitative milestones which are to be
achieved every 3 years until the area is
redesignated attainment and which
demonstrates reasonable further
progress, as defined in section 171(1),
toward timely attainment; and (4) either
a demonstration (including air quality
modeling) that the plan will provide for
attainment of the PM10 NAAQS as
expeditiously as practicable, but no later
than the end of the sixth calendar year
after the area’s designation as
nonattainment, or a demonstration that
attainment by such date is impracticable
(see, e.g., section 188(c), 189(a), 189(c),
and 172(c) of the Act). We have issued
detailed guidance on the statutory
requirements applicable to moderate
PM10 nonattainment areas [see 57 FR
VerDate Mar<15>2010
16:54 Sep 30, 2010
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13498 (April 16, 1992), and 57 FR 18070
(April 28, 1992)].
If we finalize the proposed
redesignation, the State would also be
required to submit contingency
measures (for the new PM10
nonattainment area), pursuant to section
172(c)(9) of the Act, which are to take
effect without further action by the State
or EPA, upon a determination by EPA
that an area has failed to make
reasonable further progress or attain the
PM10 NAAQS by the applicable
attainment date (see 57 FR 13510–
13512, 13543–13544). The EPA is
proposing to establish a deadline for
submission of contingency measures as
called for in section 172(b) of the Act to
coincide with the submittal date
requirement for the other SIP elements
discussed above, i.e., 18 months after
redesignation. Lastly, any new PM10
nonattainment area would be subject to
EPA’s general and transportation
conformity regulations (40 CFR part 93,
subparts A and B) upon the effective
date of redesignation. See section 176(c)
of the Act.
We will accept comments from the
public on this proposal for thirty days
from the date of publication of this
notice, and will consider any relevant
comments in taking final action on
today’s proposal.
VII. Statutory and Executive Order
Reviews
A. Executive Order 12866, Regulatory
Planning and Review
Under Executive Order 12866 (58 FR
51735, October 4, 1993), EPA has
determined that the redesignation to
nonattainment proposed today, as well
as the establishment of SIP submittal
schedules, would result in none of the
effects identified in Executive Order
12866, section 3(f). Under section
107(d)(3) of the Act, redesignations to
nonattainment are based upon air
quality considerations. The proposed
redesignation, based upon air quality
data showing that West Pinal is not
attaining the PM10 standard and upon
other air-quality-related considerations,
does not, in and of itself, impose any
new requirements on any sectors of the
economy. Similarly, the establishment
of new SIP submittal schedules would
merely establish the dates by which
SIPs must be submitted, and would not
adversely affect entities.
B. Paperwork Reduction Act
This action does not impose an
information collection burden under the
provisions of the Paperwork Reduction
Act, 44 U.S.C. 3501 et seq. Burden is
defined at 5 CFR 1320.3(b).
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C. Regulatory Flexibility Act
Under the Regulatory Flexibility Act
(RFA), 5 U.S.C. 601 et. seq., a
redesignation to nonattainment under
section 107(d)(3), and the establishment
of a SIP submittal schedule for a
redesignated area, do not, in and of
themselves, directly impose any new
requirements on small entities. See MidTex Electric Cooperative, Inc. v. FERC,
773 F.2d 327 (DC Cir. 1985) (agency’s
certification need only consider the
rule’s impact on entities subject to the
requirements of the rule). Instead, this
rulemaking simply proposes to make a
factual determination and to establish a
schedule to require the State to submit
SIP revisions, and does not propose to
directly regulate any entities. Therefore,
pursuant to 5 U.S.C. 605(b), EPA
certifies that today’s proposed action
does not have a significant impact on a
substantial number of small entities
within the meaning of those terms for
RFA purposes.
D. Unfunded Mandates Reform Act
Under Title II of the Unfunded
Mandates Reform Act of 1995 (UMRA),
Public Law 104–4, EPA has concluded
that this proposed rule is not likely to
result in the promulgation of any
Federal mandate that may result in
expenditures of $100 million or more
for State, local or tribal governments in
the aggregate, or for the private sector,
in any one year. It is questionable
whether a redesignation would
constitute a Federal mandate in any
case. The obligation for the state to
revise its State Implementation Plan that
arises out of a redesignation is not
legally enforceable and at most is a
condition for continued receipt of
federal highway funds. Therefore, it
does not appear that such an action
creates any enforceable duty within the
meaning of section 421(5)(a)(i) of UMRA
(2 U.S.C. 658(5)(a)(i)), and if it does the
duty would appear to fall within the
exception for a condition of Federal
assistance under section 421(5)(a)(i)(I) of
UMRA (2 U.S.C. 658(5)(a)(i)(I).
Even if a redesignation were
considered a Federal mandate, the
anticipated costs resulting from the
mandate would not exceed $100 million
to either the private sector or State, local
and tribal governments. Redesignation
of an area to nonattainment does not, in
itself, impose any mandates or costs on
the private sector, and thus, there is no
private sector mandate within the
meaning of section 421(7) of UMRA (2
U.S.C. 658(7)). The only cost resulting
from the redesignation itself is the cost
to the State of Arizona of developing,
adopting, and submitting any necessary
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SIP revision. Because that cost will not
exceed $100 million, this proposal (if it
is a federal mandate at all) is not subject
to the requirements of sections 202 and
205 of UMRA (2 U.S.C. 1532 and 1535).
EPA has also determined that this
proposal would not result in regulatory
requirements that might significantly or
uniquely affect small governments
because only the State would take any
action as result of today’s rule, and thus
the requirements of section 203 (2
U.S.C. 1533) do not apply.
jlentini on DSKJ8SOYB1PROD with PROPOSALS
E. Executive Order 13132, Federalism
Executive Order 13132 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.’’ This rule
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,
because it merely proposes to
redesignate an area for Clean Air Act
planning purposes and does not alter
the relationship or the distribution of
power and responsibilities established
in the Clean Air Act. Thus, the
requirements of section 6 of the
Executive Order do not apply to this
rule.
F. Executive Order 13175, 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.’’ The area proposed for
redesignation does not yet include, and
EPA is deferring action on the Ak-Chin
Indian Reservation, the Pinal County
portion of the Gila River Indian
Reservation, and TON’s Florence Village
and San Lucy Farm. In formulating its
further action on these areas, EPA has
been communicating with and plans to
continue to consult with representatives
of the Tribes, as provided in Executive
Order 13175. Accordingly, EPA has
addressed Executive Order 13175 to the
extent that it applies to this action.
G. Executive Order 13045, Protection of
Children From Environmental Health
Risks and Safety Risks
This proposed rule is not subject to
Executive Order 13045 (‘‘Protection of
Children from Environmental Health
VerDate Mar<15>2010
16:54 Sep 30, 2010
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Risks’’) (62 FR 19885, April 23, 1997),
because it is not an economically
significant regulatory action based on
health or safety risks.
H. Executive Order 13211, Actions That
Significantly Affect Energy Supply,
Distribution, or Use
This rule is not subject to Executive
Order 13211, ‘‘Actions Concerning
Regulations 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 and
Advancement Act
Section 12 of the National Technology
Transfer and Advancement Act
(NTTAA) of 1995 requires Federal
agencies to evaluate existing technical
standards when developing a new
regulation. The EPA believes that the
requirements of NTTAA are
inapplicable to this action because they
would be inconsistent with the Clean
Air Act.
J. Executive Order 12898, Federal
Actions To Address Environmental
Justice in Minority Populations and
Low-Income Populations
Today’s action proposes to
redesignate an area to nonattainment for
an ambient air quality standard. It will
not have disproportionately high and
adverse effects on any communities in
the area, including minority and lowincome communities.
List of Subjects in 40 CFR Part 81
Environmental protection, Air
pollution control, Intergovernmental
relations, National parks, Particulate
Matter, Wilderness areas.
Authority: 42 U.S.C. 7401 et seq.
Dated: September 21, 2010.
Jared Blumenfeld,
Regional Administrator, Region IX.
[FR Doc. 2010–24683 Filed 9–30–10; 8:45 am]
BILLING CODE 6560–50–P
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 261
Hazardous Waste Management
System; Identification and Listing of
Hazardous Waste; Proposed Rule
Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
AGENCY:
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EPA is proposing to grant a
petition submitted by Exxon Mobil
Beaumont Refining and Supply
Company—Beaumont Refinery
(Beaumont Refinery) to exclude (or
delist) a certain solid waste generated by
its Beaumont, Texas, facility from the
lists of hazardous wastes. EPA used the
Delisting Risk Assessment Software
(DRAS) Version 3.0 in the evaluation of
the impact of the petitioned waste on
human health and the environment.
DATES: Comments must be received on
or before November 1, 2010.
ADDRESSES: Submit your comments,
identified by Docket ID No. EPA–R06–
RCRA–2010–0066 by one of the
following methods:
1. Federal eRulemaking Portal:
https://www.regulations.gov: Follow the
on-line instructions for submitting
comments.
2. E-mail: peace.michelle@epa.gov.
3. Mail: Michelle Peace,
Environmental Protection Agency,
Multimedia Planning and Permitting
Division, RCRA Branch, Mail Code:
6PD–C, 1445 Ross Avenue, Dallas, TX
75202.
4. Hand Delivery or Courier. Deliver
your comments to: Michelle Peace,
Environmental Protection Agency,
Multimedia Planning and Permitting
Division, RCRA Branch, Mail Code:
6PD–C, 1445 Ross Avenue, Dallas, TX
75202. The Regional Office official
hours of business are Monday through
Friday, 8:30 a.m. to 4:30 p.m. excluding
Federal holidays.
Please see the direct final rule which
is located in the Rules section of this
Federal Register for detailed
instructions on how to submit
comments.
SUMMARY:
For
further technical information
concerning this document or for
appointments to view the docket or the
Beaumont Refinery facility petition,
contact Michelle Peace, Environmental
Protection Agency, Multimedia
Planning and Permitting Division,
RCRA Branch, Mail Code: 6PD–C, 1445
Ross Avenue, Dallas, TX 75202, by
calling (214) 665–7430 or by e-mail at
peace.michelle@epa.gov.
FOR FURTHER INFORMATION CONTACT:
In the
Final Rules section of this Federal
Register, EPA is approving Exxon
Mobil’s delisting petition as a direct
final rule without prior proposal
because the Agency views this as a
noncontroversial submittal and
anticipates no adverse comments. A
detailed rationale for the approval is set
forth in the direct final rule. If no
adverse comments are received in
SUPPLEMENTARY INFORMATION:
[EPA–R06–RCRA–2010–0066; SW FRL–
9208–6]
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]]>Agencies
[Federal Register Volume 75, Number 190 (Friday, October 1, 2010)]
[Proposed Rules]
[Pages 60680-60689]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-24683]
[[Page 60680]]
=======================================================================
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 81
[EPA-R09-OAR-2010-0491; FRL-9209-4]
Designation of Areas for Air Quality Planning Purposes; State of
Arizona; Pinal County; PM10
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: Pursuant to section 107(d)(3) of the Clean Air Act, EPA is
proposing to redesignate from ``unclassifiable'' to ``nonattainment''
an area generally covering the western half of Pinal County, Arizona,
for the 1987 national ambient air quality standard for particles with
an aerodynamic diameter less than or equal to a nominal 10 micrometers
(PM10), and therefore also proposing to revise the
boundaries of the existing ``rest of state'' unclassifiable area. EPA's
proposal to establish this new PM10 nonattainment area,
referred to as ``West Pinal,'' is based on numerous recorded violations
of the PM10 standard at various monitoring sites within the
county. EPA's proposed boundaries would encompass all land
geographically located within Pinal County west of the north-south line
defined by the boundary between Townships 10E and 11E, but excluding
the main reservation of the Tohono O'odham Nation (TON) and excluding
the Apache Junction portion of the existing Phoenix PM10
nonattainment area. San Carlos Apache lands, which are located in the
eastern quarter of the county, would be excluded from the proposed
nonattainment area along with the rest of the eastern half of the
county. If finalized as proposed, the new ``West Pinal''
PM10 nonattainment area would be classified as ``moderate''
by operation of law. The effect of this action would be to establish
and delineate a new PM10 nonattainment area within Pinal
County and thereby to impose certain planning requirements on the State
of Arizona to reduce PM10 concentrations within this area,
including, but not limited to, the requirement to submit, within 18
months of redesignation, a revision to the Arizona state implementation
plan that provides for attainment of the PM10 standard as
expeditiously as practicable but no later than the end of the sixth
calendar year after redesignation. Lastly, EPA is deferring action on
the status of certain tribal lands located within this area, including
the tribal lands of the Ak-Chin Indian Community and the Gila River
Indian Community, as well as TON's Florence Village and San Lucy Farm,
pending further consultation with the affected tribes.
DATES: Any comments must arrive by November 1, 2010.
ADDRESSES: Submit comments, identified by docket number EPA-R09-OAR-
2010-0491, by one of the following methods:
1. Federal eRulemaking Portal: https://www.regulations.gov. Follow
the on-line instructions.
2. E-mail: vagenas.ginger@epa.gov.
3. Mail or deliver: Ginger Vagenas (Air-2), U.S. Environmental
Protection Agency Region IX, 75 Hawthorne Street, San Francisco, CA
94105-3901.
Instructions: All comments will be included in the public docket
without change and may be made available online at https://www.regulations.gov, including any personal information provided,
unless the comment includes Confidential Business Information (CBI) or
other information whose disclosure is restricted by statute.
Information that you consider CBI or otherwise protected should be
clearly identified as such and should not be submitted through https://www.regulations.gov or e-mail. https://www.regulations.gov is an
``anonymous access'' system, and EPA will not know your identity or
contact information unless you provide it in the body of your comment.
If you send e-mail directly to EPA, your e-mail address will be
automatically captured and included as part of the public comment. 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.
Docket: The index to the docket for this action is available
electronically at https://www.regulations.gov and in hard copy at EPA
Region IX, 75 Hawthorne Street, San Francisco, California. While all
documents in the docket are listed in the index, some information may
be publicly available only at the hard copy location (e.g., copyrighted
material), and some may not be publicly available in either location
(e.g., CBI). To inspect the hard copy materials, please schedule an
appointment during normal business hours with the contact listed in the
FOR FURTHER INFORMATION CONTACT section.
FOR FURTHER INFORMATION CONTACT: Ginger Vagenas, EPA Region IX, (415)
972-3964, vagenas.ginger@epa.gov.
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us'' and
``our'' refer to EPA.
Table of Contents
I. Background
II. EPA's Decision to Address PM10 Violations Monitored
in Pinal County Through Redesignation
III. State of Arizona's Recommendation for Boundaries for New
Nonattainment Area
IV. EPA's Review of the State's Recommendation and Rationale for
Proposed Boundaries
V. EPA's Review of Recommendations From Affected Indian Tribes
VI. Proposed Action and Request for Public Comment
VII. Statutory and Executive Order Reviews
I. Background
On July 1, 1987, EPA revised the national ambient air quality
standards (NAAQS or ``standards'') for particulate matter (52 FR
24634), replacing total suspended particulates as the indicator for
particulate matter with a new indicator called PM10 that
includes only those particles with an aerodynamic diameter less than or
equal to a nominal 10 micrometers.\1\ In order to attain the NAAQS for
24-hour PM10, an air quality monitor cannot measure levels
of PM10 greater than 150 micrograms per cubic meter
([micro]g/m\3\) more than once per year on average over a consecutive
three-year period. The rate of expected exceedances, therefore,
indicates whether a monitor attains the air quality standard.
---------------------------------------------------------------------------
\1\ The 1987 PM10 standard included a 24-hour (150
micrograms per cubic meter ([micro]g/m\3\)) and an annual standard
(50 [micro]g/m\3\). In 2006, EPA revoked the annual standard. See 71
FR 61144 (October 17, 2006) and 40 CFR 50.6.
---------------------------------------------------------------------------
Most of Pinal County, Arizona, including the area that is the
subject of today's action, was included in the ``rest of state'' area,
which was designated ``unclassifiable'' for PM10 by
operation of law upon enactment of the 1990 amendments to the Clean Air
Act (CAA or ``Act'').\2\ See section 107(d)(4)(B)(iii). The
PM10 designations established by operation of law under the
CAA, as amended in 1990, are known as ``initial'' designations. The CAA
grants EPA the authority to change the designation of, or
``redesignate,'' such areas in light of changes in circumstances. More
specifically, CAA section 107(d)(3) authorizes EPA to revise the
designation of areas (or portions thereof) on the
[[Page 60681]]
basis of air quality data, planning and control considerations, or any
other air-quality-related considerations that EPA deems appropriate.
Pursuant to CAA section 107(d)(3), EPA in the past has redesignated
certain areas in Arizona to nonattainment for the PM10
NAAQS, including the Payson and Bullhead City areas. See 56 FR 16274
(April 22, 1991); and 58 FR 67334 (December 21, 1993).
---------------------------------------------------------------------------
\2\ While most of Pinal County was designated
``unclassifiable,'' two PM10 planning areas that extend
into Pinal County were designated under the CAA, as amended in 1990,
as ``nonattainment:'' The Phoenix planning area, which includes the
Apache Junction area within Pinal County; and the Hayden/Miami
planning area, which includes the northeastern portion of the
county. See 56 FR 11101 (March 15, 1991); 56 FR 56694 (November 6,
1991); and 57 FR 56762 (November 30, 1992). In 2007, we approved a
redesignation request by the State of Arizona to split the Hayden/
Miami PM10 nonattainment area into two separate
PM10 nonattainment areas. See 72 FR 14422 (March 28,
2007). Today's proposed action would not affect these pre-existing
PM10 nonattainment areas. EPA codifies area designations
in 40 CFR part 81. The area designations for the State of Arizona
are codified at 40 CFR 81.303.
---------------------------------------------------------------------------
II. EPA's Decision to Address PM10 Violations Monitored in
Pinal County Through Redesignation
As noted above, EPA has the authority under CAA section 107(d)(3)
to redesignate areas (or portions thereof) on the basis of air quality
data, planning and control considerations, or any other air-quality-
related considerations. Last year, under CAA section 107(d)(3)(A), EPA
notified the Governor of Arizona and tribal leaders of the four Indian
Tribes (whose Indian country is located entirely, or in part, within
Pinal County) that the designation for Pinal County, and any nearby
areas that may be contributing to the monitored violations in Pinal
County, should be revised. Our decision to initiate the redesignation
process stemmed from review of 2006-2008 ambient PM10
monitoring data from PM10 monitoring stations within the
county that showed widespread, frequent, and in some instances, severe,
violations of the PM10 standard.\3\
---------------------------------------------------------------------------
\3\ In a letter dated October 14, 2009, EPA notified the State
of Arizona that the PM10 designation in Pinal County
should be revised. EPA notified the tribal leaders of the Ak-Chin
Indian Community, Gila River Indian Community, San Carlos Apache
Tribe, and Tohono O'odham Nation by letters dated December 30, 2009.
---------------------------------------------------------------------------
Table 1, below, presents a summary of the latest available quality-
assured PM10 monitoring data (2007-2009). A map showing the
location of the monitors is included in our Technical Support Document
(TSD), contained in the docket for this rulemaking.
Table 1--Pinal County--PM10 Air Quality Monitoring Data, 2007-2009
------------------------------------------------------------------------
PM10 Expected
Site name AQS* ID exceedances**
2007-2009
------------------------------------------------------------------------
Apache Junction***.................. 04-021-3002-1 0
Casa Grande......................... 04-021-0001-1 0
04-021-0001-3 4.7
Combs School (Queen Creek).......... 04-021-3009-3 17.6
Coolidge............................ 04-021-3004-1 2
Cowtown (southeast of Maricopa)..... 04-021-3013-1 112.9
04-021-3013-3 139.8
Eloy................................ 04-021-3014-1 0
Mammoth............................. 04-021-3006-1 0
Marana (Pinal Air Park)............. 04-021-3007-1 0
Maricopa............................ 04-021-3010-3 12.6
Pinal County Housing/PCH (approx. 11 04-021-3011-1 6.5
miles east of Casa Grande).........
04-021-3011-2 5.9
04-021-3011-3 15.6
Riverside (Kearny).................. 04-021-3012-1 0
Stanfield (approx. 15 miles west of 04-021-3008-1 16.4
Casa Grande).......................
04-021-3008-3 17.8
Bapchule (Gila River Indian 04-021-7004-1 6.6
Community monitors)................
04-021-7004-2 7.9
------------------------------------------------------------------------
*AQS (Air Quality System) is an EPA database of ambient air quality.
**The 24-hour PM10 standard is met when the 3-year average of the
expected exceedances is equal to or less than one.
***The Apache Junction site is located in the existing Phoenix PM10
nonattainment area.
As shown in Table 1, the data from 2007-2009 reveal violations at
the PM10 monitors located in Queen Creek, Casa Grande,
Coolidge, Cowtown (which is southeast of Maricopa), Maricopa,
Stanfield, at the Pinal County Housing Complex (which is east of Casa
Grande, roughly half-way between Coolidge and Eloy), and within the
Gila River Indian Reservation. Expected annual exceedances (of the 150
[micro]g/m\3\ 24-hour standard) at these monitoring sites range from
two (at Coolidge) to more than 100 (at Cowtown). (For the purposes of
comparison, the NAAQS is met when the 3-year average of the expected
exceedances is equal to or less than one.) Maximum 24-hour
concentrations measured at a number of these sites (such as Cowtown,
Maricopa and Stanfield) can be more than two to three times the level
of the standard. In light of the widespread, frequent, and severe
violations of the PM10 standard monitored at various
monitoring sites in Pinal County, EPA continues to believe that the SIP
planning and control requirements that are triggered by redesignation
of an area to nonattainment for the PM10 NAAQS would be the
most appropriate means to ensure that this air quality problem is
remedied.
Section III of this document describes the State of Arizona's
recommendation with respect to the boundaries of this new
PM10 nonattainment area, and section IV of this document
summarizes EPA's review of the State's recommendation and rationale for
EPA's proposed boundaries. Section V describes the Indian Tribes'
recommendations and our corresponding responses. Section VI describes
our proposed action and the corresponding CAA planning requirements
that would thereby be triggered.
III. State of Arizona's Recommendation for Boundaries for New
Nonattainment Area
Pursuant to section 107(d)(3)(B) of the Act, the Governor of
Arizona responded to EPA's October 14, 2009 notification that the
PM10 designation of Pinal County, and any nearby areas that
may be contributing to violations in Pinal County, should be revised.
The Governor responded in a letter dated
[[Page 60682]]
March 23, 2010 in which the Governor recommended a partial-county
nonattainment area.\4\
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\4\ Letter from Jan Brewer, Governor of Arizona, to Jared
Blumenfeld, Regional Administrator, EPA Region IX, dated March 23,
2010.
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The boundaries of the prospective PM10 nonattainment
area recommended by the Governor of Arizona encompass a portion of
central and western Pinal County, and form an area that resembles a
backwards ``L.'' \5\ See figure 2 of EPA's TSD for a map of both the
State's recommended boundaries as well as EPA's proposed boundaries.
The state-recommended area includes all or most of the cities of
Maricopa, Coolidge, Casa Grande and the Pinal County portion of the
town of Queen Creek, as well as the western-most portion of the town of
Florence and the northern-most portion of the city of Eloy. It includes
an area that at its western-most boundary includes nearly all of the
City of Maricopa. The southern boundary is defined by a line that
coincides approximately with Interstate 8. The area continues to the
east for approximately 35 miles where it extends to the north,
including portions of Florence and Coolidge, and the Pinal County
portion of Queen Creek, and terminates just south of Apache Junction.
The eastern boundary is defined by the north-south line between
Townships 8E and 9E. The northern boundary follows the county line
south from the Apache Junction area and then follows the boundary of
the Gila River Indian Reservation to close back around to the
recommended western boundary. See the Governor's March 23, 2010 letter
for the legal description of the State's recommended boundaries by
township and range and for an enclosed map illustrating this area.
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\5\ The Governor explicitly excludes Indian country, which is
appropriate given that the State of Arizona is not authorized to
administer programs under the CAA in the affected Indian country.
The ``backwards L'' shape of the recommended area is partly
explained by this exclusion because the recommended area partially
surrounds Indian country.
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In support of the Governor's recommendation, on March 26, 2010, the
Arizona Department of Environmental Quality (ADEQ) submitted to EPA a
technical report entitled, ``Arizona Air Quality Designations,
Technical Support Document, Boundary Recommendation for the Pinal
County 24-hour PM10 Nonattainment Area (March 15, 2010),''
(herein referred to as ADEQ's ``technical report''). ADEQ's technical
report compiles and evaluates information addressing nine factors \6\
derived from and discussed in EPA guidance on designation criteria; see
citation on page 2 of ADEQ's technical report to Memorandum from Robert
J. Meyers, EPA Acting Assistant Administrator, ``Area Designations for
the Revised 24-Hour Fine Particle National Ambient Air Quality
Standard,'' dated June 8, 2007.
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\6\ The nine factors considered in ADEQ's technical report are
air quality data, emissions data, population density and degree of
urbanization, traffic and commuting patterns, growth rates and
patterns, meteorology, geography/topography, jurisdictional
boundaries, and level of control of emission sources.
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ADEQ points to a number of elements that it believes support the
recommended boundaries. Specifically, ADEQ claims that its recommended
area would include: all of the violating monitors; the majority of
PM10 emissions generated within the county; the vast
majority of the county's population; the rapidly growing urbanized and
developed areas, high-traffic Interstate corridors and areas with the
highest employment densities; the significant growth areas along
Interstates 8 and 10; and the agricultural basin where stagnation
conditions are known to impact PM10 concentrations. ADEQ
also believes that its recommended redesignation would maintain
jurisdictional cohesiveness. To buttress its recommended exclusion of
eastern Pinal County from the new nonattainment area, ADEQ compares
these factors as they apply to western Pinal County with those for
eastern Pinal County. ADEQ asserts that in contrast to the western
portion of Pinal County, the eastern portion has no violating monitors,
contains few emissions sources (other than certain major sources that
are already included in an existing PM10 nonattainment
area), is largely undeveloped and has limited growth potential. As set
forth below in more detail, while EPA believes this characterization
applies to the eastern half of Pinal County, EPA also believes that the
western portion that should be redesignated is far more extensive than
the State's recommendation.
IV. EPA's Review of the State's Recommendation and Rationale for
Proposed Boundaries
CAA section 107(d)(1)(A) generally defines a nonattainment area as
any area that does not meet, or that contributes to ambient air quality
in a nearby area that does not meet, the national primary or secondary
ambient air quality standard for the relevant pollutant. Thus, in
reviewing the State's recommended boundaries, EPA has considered not
only areas where violations of the relevant NAAQS have been monitored,
but also that contribute to such violations.
EPA guidance \7\ provides for the use of ``a qualitative analysis
of the area of representativeness of the monitoring station, together
with the consideration of terrain, meteorology, and sources of
emissions * * *'' in defining nonattainment area boundaries for
PM10. Consistent with that guidance, EPA generally
recommends that States identify nonattainment area boundaries based on
the weight of evidence of the following factors and other relevant
information:
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\7\ PM10 SIP Development Guideline, EPA-450/2-86-001,
June 1987.
--Air quality data;
--Pollutant emissions;
--Population density and degree of urbanization;
--Traffic and commuting patterns;
--Growth;
--Meteorology;
--Geography and topography;
--Jurisdictional boundaries; and
--Level of control of emissions sources.
See, e.g., Memorandum from Robert J. Meyers, EPA Acting Assistant
Administrator, ``Area Designations for the Revised 24-Hour Fine
Particle National Ambient Air Quality Standard,'' dated June 8, 2007.
EPA also looks to the same kinds of factors in the context of
redesignations. See, e.g., EPA's proposed (73 FR 22307, at 22308-22310,
April 25, 2008) and final approval (73 FR 66759, November 12, 2008) of
a state request to redesignate the San Joaquin Valley PM10
nonattainment area. In addition, CAA section 107(d)(3)(A) allows EPA,
in redesignating areas to nonattainment, to take into consideration
``any other air-quality-related considerations.'' In its technical
report, ADEQ refers to the nine factors in developing the State's
recommended boundaries for the new PM10 nonattainment area.
In the following paragraphs, we review and evaluate ADEQ's nine factor
analysis.
Air Quality Data. ADEQ's technical report summarizes 2006-2008
PM10 monitoring data from 12 monitoring sites within Pinal
County. Most of the monitoring sites are located in the west central
portion of the county (Maricopa, Cowtown, Stanfield, Casa Grande, Pinal
County Housing Complex, and Coolidge). Two are located in the southern
portion (Eloy and Pinal Air Park); two are located in the northern
portion [Apache Junction and Combs School (located in Queen Creek)];
and two are located in the far eastern portion of the county (Riverside
and Mammoth). The Apache Junction and Riverside
[[Page 60683]]
monitoring sites are located within existing PM10
nonattainment areas.
Based on 2006-2008 data, ADEQ finds six of the monitoring sites to
be in violation of the PM10 NAAQS. EPA has updated this
monitoring information by reviewing 2007-2009 data. Although we find
that these data are largely consistent with the data presented by ADEQ,
the more recent data set shows seven violating monitors (not counting
the PM10 monitoring site on the Gila River Indian
Reservation) rather than six. Coolidge is the additional monitoring
site that is newly violating based on the more recent data set. In its
technical report, ADEQ notes that its proposed boundaries include the
locations of all of the violating monitors within Pinal County. While
we agree that Arizona's proposed boundaries do in fact include all of
the violating monitors (i.e., other than the monitoring site located
within the Gila River Indian Reservation and those located within
existing PM10 nonattainment areas), we disagree with ADEQ's
contention that its proposed boundaries include all areas that do not
experience violations but nonetheless contribute to the violations that
are recorded at the monitoring sites based on an evaluation of the
other eight factors as discussed in the following paragraphs.
Emissions Data. ADEQ developed an annual emissions inventory of
PM10 sources in the county for the year 2007 for the purpose
of defining a boundary for the new nonattainment area. ADEQ's inventory
relies on a number of different data sources, assumptions, and methods
(including EPA's MOBILE model and compilation of emissions factors (AP-
42)) to calculate annual PM10 emissions in the county.
ADEQ's inventory points to fugitive emissions from vehicular traffic on
paved and unpaved roads as the single largest source category, followed
in importance by agricultural sources (including concentrated animal
feeding operations), industrial sources, and construction. ADEQ's
technical report includes maps that show the relative distribution of
emissions generated within the county using 4-kilometer grid cells. See
in particular the following maps in the State's technical report:
Figure 3-3 on page 8 (all PM10 sources) and figure 3-4 on
page 11 (paved and unpaved on-road sources). The maps show that
PM10 emissions in the county are concentrated in the western
half of the county, with the highest emissions densities in the west
central portion of the county. In contrast, the eastern half of the
county (outside of the existing nonattainment areas) is characterized
predominantly by the lowest category of emissions densities (i.e., 0 to
20 tons per year per 4-kilometer grid). See page 8 of ADEQ's technical
report.
While EPA finds that the PM10 emissions inventory for
Pinal County and ADEQ's corresponding maps are helpful in defining the
boundaries of the new nonattainment area, we do not believe that they
justify ADEQ's conclusions about its recommended boundaries. ADEQ
claims that the emissions inventory and maps demonstrate that sources
in the eastern and southern regions of the county do not
``significantly contribute'' to violations in the other regions of the
county. See page ES-3 of ADEQ's technical report. EPA notes, however,
that CAA section 107(d)(1)(A) defines a nonattainment area as one that
does not meet, or that ``contributes to'' ambient air quality in a
nearby area that does not meet the NAAQS. The definition of
nonattainment areas is not limited to areas that, in ADEQ's words,
``significantly'' contribute to a violating area. Moreover, ADEQ's maps
show that areas immediately to the east and south of the recommended
area (but still within the western half of the county) include the same
types of emissions sources, with similar emissions densities, as those
that predominate within the recommended area. For example, figure 3-3
(page 8 of State's technical report) shows emissions densities similar
to those estimated within the State's recommended boundaries to the
east in Coolidge and Florence, as well as south to Eloy. In addition,
figures 3-4, 3-7, and 3-10 (on pages 11, 14, and 17, respectively, of
the State's technical report) illustrate the locations of unpaved roads
(with average daily traffic volumes greater than 100) and show that
higher relative concentrations of PM10 emissions from such
sources as vehicle entrainment of dust over paved and unpaved roads,
tilling and harvesting, and concentrated animal feeding operations
(CAFOs) extend to central, and south central Pinal County. Thus, the
emissions inventory data and related maps do not support the State's
recommended boundaries but rather argue for a larger nonattainment area
consisting of the western half of the county.
In contrast, EPA's proposed boundaries include all of the areas for
which emissions data show relatively higher PM10 emissions
from the types of sources contributing the most to the overall
PM10 emissions inventory. For instance, based on the
information sources described above in the State's technical report,
EPA's proposed boundaries include the areas of relatively higher
emissions densities in and around Coolidge, Florence, and Eloy that
reflect the same types of PM10-generating activities
(vehicle entrainment of dust over paved and unpaved roads, tilling and
harvesting, and CAFOs) as found within the smaller nonattainment area
boundaries recommended by the State.
Population density, degree of urbanization, growth rate and
patterns. This factor reflects EPA's belief that the size, density, and
location of population can be indicative of emissions activity that
contributes to violations of the PM10 NAAQS in an area.
ADEQ's technical report presents population growth and density figures
for municipalities in Pinal County. The data show that Pinal County has
grown dramatically over the past decade (nearly doubling from a
population of approximately 180,000 in 2000 to nearly 360,000 in 2008).
EPA independently collected and reviewed population-related information
and notes that the populations of the largest cities and towns in the
western half of the county, such as (the city of) Maricopa (2008
population of approximately 46,000), Casa Grande (41,000), Apache
Junction (33,000), Florence (21,000), and Eloy (13,000), contrast
sharply with much smaller populations in the largest cities and towns
in the eastern half of the county, including Superior (3,000), Kearny
(3,000), and Mammoth (3,000). See page 14 of EPA's TSD.
ADEQ also submitted maps showing population densities both under
current conditions and projections for the year 2030 when the
population of Pinal County is anticipated to exceed 1,000,000. Under
existing conditions, higher population densities are found in the west
central portion of the county, but there are also population centers in
the northern (Apache Junction and Queen Creek) and southern portions
(Eloy) of the county. ADEQ's maps show that future growth is expected
to be concentrated in the Interstate 8 and 10 corridors, which extend
through the west central and southern portions of the county, although
a certain amount of growth is also expected in the Falcon Valley area
farther to the east.
In its technical report, ADEQ concludes that the eastern and
southern portions of the county are largely undeveloped and have very
low population densities, and finds that this information provides
support for the State's recommended boundaries. However, like the
emissions data discussed above, we believe that the data do not justify
the restricted nature of the State's recommended boundaries, which
exclude much of the western half of the County. Specifically, EPA
[[Page 60684]]
believes that the State's recommended exclusion of areas in the eastern
and southern sections of the western half of the county is contradicted
by evidence showing that land use development in Pinal County extends
further east and south than the State's recommended boundaries. For
example, the State's recommended boundaries fail to include the
agricultural and more urbanized uses in and around Eloy and the future
growth areas along the two Interstate corridors. See figures 3-13 and
3-14 from the State's technical report. In contrast, EPA's proposed
boundaries would include all of the western half of Pinal County
(excluding TON's main reservation and the Apache Junction portion of
the Phoenix PM10 nonattainment area) and thereby would
include the areas with relatively higher population densities and most
of the areas where significant levels of growth are expected.
Traffic and commuting patterns. This factor considers the commuting
patterns of residents in, and commuters to, Pinal County. More
specifically, this factor considers the number of commuters in each
surrounding county who drive to Pinal County, the percent of total
commuters in each county who commute to Pinal County, the percent of
total commuters in each county who commute into the statistical area in
which Pinal County is located, as well as the total vehicle miles
traveled (VMT) for each county.
ADEQ's technical report (page 23) presents statistics from the 2000
census quantifying the number of commuters from each county within the
State of Arizona to jobs within Pinal County, and the number of
commuters residing in Pinal County to jobs in Maricopa and Pima
counties. The data from 2000 indicate that approximately 10,000
commuters, or roughly 20% of total commuters to jobs within Pinal
County, reside outside of Pinal County. Conversely, approximately
36,000 (roughly 80%) of commuters travel solely within Pinal County.
Almost 80% of the out-of-county commuters reside to the north in
Maricopa County, and nearly all remaining out-of-county commuters
commuting to Pinal County reside to the south in Pima County. Moreover,
nearly 40% of commuters residing in Pinal County work in either
Maricopa or Pima counties, whereas 60% of commuters residing in Pinal
County also work in Pinal County.
EPA independently reviewed these same data and observed that the
principal route for traffic through Pinal County (serving in-county as
well as out-of-county commuters) is Interstate 10, which bisects the
western half of the county and connects metropolitan Phoenix (largely
in Maricopa County) to the north with metropolitan Tucson (in Pima
County) to the south. ADEQ cites traffic and commuting patterns as a
factor supporting the exclusion of the eastern half of the county from
the new nonattainment area. While EPA agrees that it is reasonable to
distinguish between the eastern and western halves of the county, EPA
believes that the data indicate that the entire western half of the
county, and not a small portion of it, as the State recommends, should
be redesignated to nonattainment. Thus, EPA finds that traffic and
commuting patterns do not make a case for the state's recommendation,
but rather lend support to the creation of a larger nonattainment area
generally encompassing the western half of the County. See figure 3-17
from the State's technical report, which shows much higher employment
densities projections for year 2030 in the western half of the county
than those in the eastern half but which also show higher employment
densities east and south of the State's recommended boundaries (but
still within the western half of the county).
Meteorology. Generally, the analysis of meteorology looks to wind
data for evidence that emissions originating from areas in certain
locations relative to violating monitors may be more prone to
contribute than emissions originating from sources located elsewhere.
ADEQ's technical report describes the dynamics responsible for region-
wide weather patterns and the associated winds blowing across Arizona,
as well as the frequent occurrence of ``drainage'' winds, which occur
when large-scale weather influences wane. ADEQ describes how steep
pressure gradients result from strong high pressure building over the
western United States and low pressure to the east. As the high
pressure builds, a steep pressure differential is created that causes
strong winds over Arizona to entrain and transport dust from in-county
and out-of-county sources. These can cause elevated PM10
concentrations. ADEQ also notes however, that not all exceedances of
the PM10 standard are wind-related and that stagnation
conditions in the fall and winter occur when cold air and the absence
of winds trap ambient PM10 in the lower atmosphere. ADEQ
notes that the region of the county most impacted by stagnation
conditions is the western agricultural basin.
The State recommends including the agricultural basin region of the
county where stagnation conditions are known to impact PM10
concentrations. While we agree that the new nonattainment area should
include the agricultural basin region where stagnation conditions
occur, we find that the State's recommended boundaries do not in fact
accomplish this. As shown on page 14 of the ADEQ's technical report,
the agricultural basin region of the county, roughly defined based on
tilling and harvesting emissions within the county, lies in the western
half of the county, and also extends south of Interstate 10 towards the
southern county line. Moreover, as discussed in the following
paragraph, a review of available wind data supports the inclusion of
areas to the south and east of the violating monitors (i.e., beyond the
State's recommended boundaries) based on the prevalence of winds from
the southeast quadrant.
EPA has considered the information provided by ADEQ but also
reviewed available wind data for Pinal County and finds that winds are
similar throughout central and western Pinal County in that the
predominant wind directions are from the southeast quadrant. See figure
10 of EPA's TSD. (We note that winds blow out of the north and
northwest far less frequently, making transport of PM10 from
the metropolitan Phoenix area unlikely under most circumstances.) In
this instance, the predominance of southeast winds support boundaries
that extend south and east of the violating monitors because
PM10 sources, including agricultural activities and unpaved
roads, are found in those directions. EPA's recommended boundaries
encompass the types of sources that are believed to cause or contribute
to the monitored violations and that are located east and south of the
violating monitors, whereas the State's recommended boundaries largely
exclude these sources. See figure 2 (PM10 monitors, ADEQ's
recommended nonattainment area boundary, and EPA's proposed
nonattainment area boundary), figure 4 (Pinal County agriculture,
cattle operations, and unpaved roads), and figure 5 (ADEQ's map
illustrating the distribution of emissions in Pinal County) from EPA's
TSD.
Lastly, EPA recognizes that high wind events do occur in Pinal
County, and that some of these events may result in monitored
particulate matter exceedances that qualify as caused by exceptional
events under EPA's exceptional events rule.\8\ However, as
[[Page 60685]]
ADEQ itself acknowledges, even if EPA were eventually to determine that
all of the exceedances that ADEQ has flagged are caused by
``exceptional events,'' the area would still clearly be in violation of
the PM10 NAAQS.
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\8\ On March 22, 2007, EPA adopted a final rule, Treatment of
Data Influenced by Exceptional Events, to govern the review and
handling of certain air quality monitoring data for which the normal
planning and regulatory processes are not appropriate. Under the
rule, EPA may exclude data from use in determinations of National
Ambient Air Quality Standard (NAAQS) exceedances and violations if a
state demonstrates that an ``exceptional event'' caused the
exceedances, and satisfies other criteria set forth by the rule. See
72 FR 13560.
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Geography/Topography. The geography/topography factor evaluates
physical features of the land that might have an effect on the airshed,
and therefore, on the distribution of particulate matter over an area.
In its technical report, ADEQ describes the topography of Pinal County
in terms of a broad basin, low in elevation (roughly 1,200 feet in
elevation), surrounded on all sides by mountain ranges. ADEQ finds that
topographic considerations support the State's inclusion of the basin
region of the county, which is characterized by open-ended valleys with
few topographic barriers, within the recommended boundaries.
Conversely, ADEQ finds that topographic considerations support the
State's exclusion from the recommended boundaries of the eastern
portion of the county, which is characterized by rough terrain and
steep mountain ranges reaching over 7,000 feet in elevation.
EPA too has considered topography and generally agrees with ADEQ's
description of the topography of Pinal County. We believe that the
various mountain ranges found on each side of the county inhibit
transport of PM10 (which is largely crustal in composition--
see figure 6 of EPA's TSD) from outside the county to the violating
monitors within the county. Within the county itself, we believe that
the mountains in the eastern quarter of the county, which rise to
approximately 6,000 feet near the eastern borders with Gila and Graham
counties, inhibit intra-county transport from sources located in the
eastern quarter to the violating monitors. See figure 11 of EPA's TSD.
(The portion of the San Carlos Apache Reservation that lies within
Pinal County is located in the eastern quarter of the county.)
However, the existence of the steep mountain ranges in the eastern
quarter of the County does not justify ADEQ's recommendation to exclude
from redesignation a much larger section of the western half of the
County. EPA believes that, taking other factors into account, the
western half of the County, located in the basin region that features
few topographic barriers, should be redesignated to nonattainment.
Indeed, it is arguable that topography alone would lend support to
redesignating a far larger area than EPA is proposing, one that would
encompass the entire county, excepting only the eastern quarter.
However, EPA believes that topography when evaluated in the context of
the various other factors, supports redesignation of the western half
of the county, rather than the much more restricted boundaries that
ADEQ suggests.
Jurisdictional Boundaries. The analysis of jurisdictional
boundaries evaluates the planning and organizational structure of an
area to determine if the implementation of controls in a potential
nonattainment area can be carried out in a cohesive manner. ADEQ's
technical report notes the absence of any certified metropolitan
planning organization (MPO) for Pinal County and the exclusion of
Indian country from the State's recommendation. As such, ADEQ concludes
that the State's recommended boundaries maintain jurisdictional
cohesiveness requiring no new institutional arrangements for
accomplishing required tasks.
EPA also considered the planning and organizational structure of
the State of Arizona and Pinal County (cities, towns, and
unincorporated areas), but also took into account Indian country, to
ensure that the implementation of controls within the prospective
nonattainment area could be carried out in a cohesive manner. ADEQ
exercises overall jurisdiction over environmental programs in the State
of Arizona (i.e., excluding Indian country). Under state law, ADEQ has
the responsibility for preparing air quality attainment and maintenance
plans in Pinal County. With respect to permitting and enforcement, the
Pinal County Air Quality Control District (AQCD or ``District'') has
jurisdiction over most types of stationary sources operating, or
proposing to locate, within Pinal County, but state law retains ADEQ's
statewide jurisdiction over certain types of stationary sources
(smelters, refineries, coal-fired power plants, and agricultural
operations). Neither ADEQ nor the District have jurisdiction within
Indian country.
In its technical report, ADEQ notes that five cities and towns
(Casa Grande, Coolidge, Eloy, Florence, and City of Maricopa), as well
as a portion of a sixth (Queen Creek) are located in central and
western Pinal County. ADEQ indicates that the incorporated boundaries
of these municipalities have been taken into account in developing the
nonattainment area boundaries. However, EPA's review of the
incorporated boundaries of these municipalities (see, e.g., figure 2 of
EPA's TSD) shows that the State's recommended boundaries omit portions
of the City of Maricopa and Coolidge, and most of Florence and Eloy. In
contrast, EPA's proposed nonattainment area boundaries encompass all of
these cities and towns, where most of the county's population resides.
Inclusion of entire cities and towns within the nonattainment area
boundaries would facilitate attainment planning to the extent that such
local governments will ultimately be relied upon for development and/or
implementation of specific PM10 control measures.
Level of Control of Emission Sources. The level of control factor
looks at the emissions controls currently implemented in each area. As
a general matter, most existing and proposed stationary sources within
Pinal County (excluding Indian country) are subject to the generally
applicable prohibitory rules and permitting requirements established by
the Pinal County AQCD, or, in the case of certain types of stationary
sources (smelters, refineries, coal-fired power plants, and
agricultural operations), State prohibitory rules and permitting
requirements established by ADEQ.
Pinal County AQCD has established rules for dust abatement purposes
that apply within a subarea of Pinal County established under state law
(Arizona Revised Statutes section 49-541) and referred to as ``Area
A.'' Within Pinal County, ``Area A'' generally refers to an area
encompassing the Pinal County portions of Apache Junction and Queen
Creek. Pinal County has also adopted a number of ordinances that are
also intended to reduce dust generated within ``Area A.'' These include
ordinances placing restrictions on residential fireplaces, leaf
blowers, open burning, vehicle commute trips, and vehicle idling. For
one township located within ``Area A,'' the township included in the
Phoenix Area PM10 nonattainment area (i.e., Township 1
north, range 8 east; referred to as ``Apache Junction''), Pinal County
AQCD has adopted further dust abatement rules.\9\ The State's
recommended boundaries include a portion, but not all, of ``Area A.''
In contrast, EPA's proposed boundaries for the new nonattainment area
would encompass
[[Page 60686]]
all of ``Area A,'' thereby facilitating review and modification of
these existing PM10 emissions controls within the broader
SIP attainment planning context.
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\9\ The township referred to as Apache Junction would be
unaffected by our proposed action and would remain part of the
Phoenix planning area, which is designated as a ``serious''
PM10 nonattainment area.
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Conclusion. CAA section 107(d)(3)(C) provides that after notifying
the Governor of State of its intent to redesignate an area, EPA shall
promulgate the redesignation, if any, of the area or portion thereof,
submitted by the Governor, ``making such modifications as EPA may deem
necessary. * * *'' Pursuant to CAA section 107(d)(3), we have reviewed
the State's recommendation (dated March 23, 2010) and related technical
report (submitted on March 26, 2010).
Both EPA and the State agree that sources outside of the county do
not contribute to PM10 violations at the violating monitors
within the county, and that sources in the eastern half of the county
do not contribute to the violating monitors (which are concentrated in
the central and western portions of the county). But while EPA and the
State both use the nine-factor analysis for evaluation of the
prospective nonattainment area boundaries, we reach quite different
conclusions.
As explained above, and more fully in EPA's TSD, EPA does not
believe that the State's recommended boundaries encompass the full
geographic area from which emissions-generating activities contribute
to the monitored PM10 violations. More specifically, we
believe that the Governor's recommended boundaries, which cut through
municipalities and contiguous expanses of agricultural fields, exclude
sources that have been identified as dominant sources of
PM10 and that are contributing to elevated levels of
PM10 at violating monitors.
We believe that our proposed boundaries, which are defined as all
land geographically located within Pinal County west of the north-south
line defined by the boundary between Townships 10E and 11E, but
excluding TON's main reservation and excluding the existing Apache
Junction portion of the existing Phoenix PM10 nonattainment
area, encompass the areas in which PM10 violations are being
monitored, as well as the areas that contribute to the monitored
violations, and that they are thus consistent with the definition of
nonattainment areas in CAA section 107(d)(1)(A). Our conclusion is
based on EPA's analysis of the factors as set forth in the body of this
document and in further detail in the TSD. In sum, we base our proposed
boundaries on the following considerations: (1) Monitored violations
occur in the west, central and northern portions of the western half of
the county, not in the eastern half (i.e., outside of existing
PM10 nonattainment areas); (2) the emissions from
agricultural operations, feedlots, dairies, and other cattle
operations, as well as roads, are concentrated in the western half of
the county; (3) population densities are much greater in the western
half of the county than in the eastern half and growth is expected to
be concentrated primarily along the Interstate corridors that extend
through the western half of the county; (4) Interstate 10, which
connects Pinal County with the employment centers in metropolitan
Phoenix and Tucson, bisects the western half of Pinal County; (5)
predominant southeasterly winds support inclusion of PM10
sources in areas to the south and east of the violating monitors; (6)
the western half of Pinal County encompasses the incorporated
boundaries of all of the cities in Pinal County (Apache Junction, Casa
Grande, Coolidge, Eloy, Maricopa), as well as the larger towns
(Florence and Queen Creek) thereby potentially facilitating
implementation of future control measures; and (7) dust abatement
measures already in effect in ``Area A'' (within Pinal County) can
readily be applied, as necessary and appropriate, throughout the other
portions of the western half of Pinal County. A map comparing the
State's recommended boundaries to EPA's proposed boundaries is included
as figure 2 in our TSD.
EPA therefore deems it necessary and appropriate to propose
boundaries that differ from the State's recommended boundaries and that
we believe better satisfy air quality data, planning, control and other
air-quality-related considerations. CAA Section 107(d)(3). Under CAA
section 107(d)(3)(C), EPA must notify the State whenever EPA intends to
modify State recommendations concerning boundaries for areas to be
redesignated, at least 60 days prior to EPA promulgation of final
redesignations. EPA intends to notify the State of Arizona of our
proposed action soon after this notice is signed.
V. EPA's Review of Recommendations From Affected Indian Tribes
Ak-Chin Indian Community. The Ak-Chin Indian Community is located
in western Pinal County, and is included in the existing ``rest of
state'' unclassifiable area for PM10. The Ak-Chin Indian
Community does not operate a PM10 monitoring site, but lies
in proximity to several PM10 monitoring sites that do
monitor violations of the PM10 NAAQS (e.g., the Maricopa and
Cowtown sites). In a letter dated September 2, 2010 the Ak-Chin Indian
Community responded to EPA's December 30, 2009 letter concerning the
PM10 designation of Pinal County with a recommendation that
the Ak-Chin lands be designated attainment/unclassifiable. We have
offered formal consultation to the Ak-Chin Indian Community and have
decided to defer action on redesignation of the Ak-Chin Indian
Community for PM10 to allow time for formal consultation to
occur and for further consideration of this issue as part of that
process. If in the future EPA decides to take action to redesignate the
Ak-Chin Indian Community, the Agency will do so in a separate
rulemaking.
Gila River Indian Community. The Gila River Indian Community (GRIC)
is a community located on 374,000 acres in south central Arizona.
Approximately one-third of GRIC lies within Maricopa County and two-
thirds lies within Pinal County. The Maricopa County portion of GRIC is
included in the Phoenix Area PM10 nonattainment area. The
Pinal County portion of GRIC is included in the existing ``rest of
state'' unclassifiable area for PM10. GRIC operates a
PM10 monitoring site in the Pinal County portion of its
lands and GRIC's monitor has recorded a number of PM10
exceedances. See table 1 above in this document. However, GRIC has
flagged a significant number of these exceedances as caused by
``exceptional events'' under EPA's exceptional event rule (50 CFR
50.14), and EPA has not yet taken action to determine whether any of
these data should be excluded on that basis from consideration in a
redesignation action. In October 2009, EPA approved GRIC's application
for treatment in the same manner as a state for the purposes of CAA
section 107(d) air quality designations. More recently, we proposed
approval of GRIC's submitted tribal implementation plan. See 75 FR
48880, August 12, 2010.
As noted above, on December 30, 2009, EPA notified GRIC that the
PM10 designation for Pinal County should be revised. GRIC
first indicated orally, and later confirmed in a letter dated May 27,
2010, that the community would not be making a recommendation for
PM10 until formal consultation is conducted. By letter dated
April 30, 2010, EPA responded to GRIC's oral request with an offer of
formal consultation. As with the Ak-Chin Indian Community, we have
decided to defer action on a decision whether to redesignate GRIC to
allow time for formal consultation to occur and for further
consideration of this issue as part of that process. In
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addition, the deferral for GRIC will provide EPA with the time
necessary to address the exceptional events issues. If in the future
EPA decides to undertake redesignation of the Pinal County portion of
the Gila River Indian Community, the Agency will do so in a separate
rulemaking.
San Carlos Apache Tribe. The San Carlos Apache Reservation extends
over a portion of eastern Pinal County, as well as portions of Gila and
Graham counties. A section of the Pinal County portion of the San
Carlos Apache Reservation lies in the existing Hayden PM10
nonattainment area. The rest of the Pinal County portion of the
reservation is located within the ``rest of state'' unclassifiable area
for PM10. The San Carlos Apache Tribe did not respond to
EPA's December 30, 2009 letter concerning the PM10
designation in Pinal County.
For the reasons discussed in section IV of this document, we
believe that emissions sources in the eastern half of Pinal County do
not contribute to violations monitored in the western half of the
county, and thus are proposing only that the western half of the county
(excluding TON's main reservation and the Apache Junction portion of
the existing Phoenix PM10 nonattainment area) be
redesignated to nonattainment. Given that the San Carlos Tribe's Indian
country extends only into far eastern Pinal County, we propose to
retain the Tribe's current designations for the PM10
standard (i.e., a portion remains in the existing Hayden
PM10 nonattainment area, and a portion remains in the
existing ``rest of state'' unclassifiable area).
Tohono O'odham Nation. The Tohono O'odham Nation (TON) extends over
portions of Pima, Maricopa and Pinal counties. TON's main reservation
covers much of southwestern Pinal County and extends over portions of
Pima and Maricopa counties. TON's lands also include a small area
(approximately 25 acres), known as Florence Village, which is located
approximately two miles west of the town of Florence in central Pinal
County, and a 3,200-acre parcel east of the main reservation called San
Lucy Farm. With the exception of a small portion of TON included within
the existing Rillito PM10 nonattainment area (which is
located in Pima County), TON is included in the ``rest of state''
unclassifiable area for PM10.
In a letter dated February 11, 2010, TON responded to EPA's
December 30, 2009 letter concerning the PM10 designation in
Pinal County with a recommendation that the TON land within Pinal
County be designated attainment/unclassifiable for PM10.
With respect to the main reservation in southwestern Pinal County, we
agree with TON's recommendation and are proposing a nonattainment area
with boundaries that exclude TON's main reservation. We agree with
TON's recommendation in this regard because (1) the closest violating
monitors (Stanfield and Casa Grande) are located in the midst of the
county's agricultural basin, well north of TON's main reservation; (2)
the types of emissions sources believed to be responsible for the
PM10 violations, such as agricultural operations, feedlots,
and dairies (see figure 4 of EPA's TSD), as well as roads, are largely
absent from TON; (3) the population density of TON is very low, and is
an order of magnitude less than the average population density of Pinal
County (see table 5 of EPA's TSD); and (4) TON is a separate sovereign
not subject to state or county jurisdiction thereby complicating
planning and implementation issues. We conclude therefore that TON's
main reservation is not contributing to the PM10 violations
monitored elsewhere in Pinal County and propose to exclude TON from the
new nonattainment area. Under this proposal, the designation of TON's
main reservation would remain unchanged, i.e., it would remain part of
the ``rest of state'' unclassifiable area for PM10.
As to Florence Village and San Lucy Farm, EPA is deferring
redesignation to allow for further consultation with TON. If in the
future EPA decides to take action to redesignate TON's Florence Village
and San Lucy Farm, the Agency will do so in a separate rulemaking.
VI. Proposed Action and Request for Public Comment
Pursuant to section 107(d)(3) of the Clean Air Act and based on our
evaluation of air quality data, planning, control and other air-
quality-related information and considerations, and our review of the
Governor's recommendation, EPA is proposing to redesignate from
``unclassifiable'' to ``nonattainment'' an area generally covering the
western half of Pinal County, Arizona, for the 1987 PM10
NAAQS and therefore to revise the boundaries of the existing ``rest of
state'' unclassifiable area. EPA's proposal to establish this new
PM10 nonattainment area, referred to as ``West Pinal,'' is
based on numerous recorded violations of the PM10 standard
at various monitoring sites within the county, and on the other grounds
set forth in this document and in the TSD.
EPA's proposed boundaries for the nonattainment area would
encompass all of the area recommended by the State of Arizona, but
would extend further to the east and south, and to a lesser degree, to
the north and west. EPA's proposed boundaries would encompass all land
geographically located within Pinal County west of the north-south line
defined by the boundary between Townships 10E and 11E, but excluding
TON's main reservation and excluding the Apache Junction portion of the
existing Phoenix PM10 nonattainment area. If finalized as
proposed, the new ``West Pinal'' PM10 nonattainment area
would be classified as ``moderate'' by operation of law. See figure 2
of EPA's TSD for a map showing EPA's proposed boundaries.
We believe that our proposed boundaries as described above
encompass the areas in which PM10 violations are being
monitored, as well as the areas that contributes to the monitored
violations, and that they are thus consistent with the definition of
nonattainment areas in CAA section 107(d)(1)(A). Our conclusion is
based on EPA's analysis of the factors as set forth in the body of this
document and in further detail in the TSD. We find support for our
proposed boundaries based on the following considerations: (1)
Monitored violations occur in the west, central and northern portions
of the western half of the county, not in the eastern half (i.e.,
outside of existing PM10 nonattainment areas); (2) the
emissions from agricultural operations, feedlots, dairies, and other
cattle operations, as well as roads, are concentrated in the western
half of the county; (3) population densities are much greater in the
western half of the county than in the eastern half and growth is
expected to be concentrated primarily along the Interstate corridors
that extend through the western half of the county; (4) Interstate 10,
which connects Pinal County with the employment centers in metropolitan
Phoenix and Tucson, bisects the western half of Pinal County; (5)
predominant southeasterly winds support inclusion of PM10
sources in areas to the south and east of the violating monitors; (6)
the western half of Pinal County encompasses the incorporated
boundaries of all of the cities in Pinal County (Apache Junction, Casa
Grande, Coolidge, Eloy, Maricopa), as well as the larger towns
(Florence and Queen Creek) thereby potentially facilitating
implementation of future control measures; and (7) dust abatement
measures already in effect in ``Area A'' (within Pinal County) can
readily be applied, as necessary and appropriate, throughout the other
[[Page 60688]]
portions of the western half of Pinal County.
EPA has determined that activities occurring on the main Tohono
O'odham Nation (TON) reservation are not causing or contributing to
violations occurring in Pinal County and we are therefore proposing to
exclude the main TON reservation from the new nonattainment area. San
Carlos Apache lands, which are located in the eastern quarter of the
county, would be excluded from the proposed nonattainment area along
with the rest of the eastern half of the county. EPA is deferring its
decision regarding redesignation of the Ak-Chin and Gila River Indian
Community lands, as well as TON's Florence Village and San Lucy Farm,
pending consideration of issues unique to tribal lands, completion of
formal consultation with the tribal governments, and (in the case of
GRIC) consideration of exceptional events flags. The existing Phoenix
PM10 nonattainment area (including the Apache Junction
portion of western Pinal County) would be unaffected by this action.
Areas redesignated as nonattainment, as proposed herein, are
subject to the applicable requirements of part D, title I of the Act
and will be classified as moderate by operation of law (see section
188(a) of the Act). Within 18 months of the redesignation, the State is
required to submit to EPA an implementation plan for the area
containing, among other things, the following requirements: (1)
Provisions to assure that reasonably available control measures
(including reasonably available control technology) are implemented
within 4 years of the redesignation; (2) a permit program meeting the
requirements of section 173 governing the construction and operation of
new and modified major stationary sources of PM10; (3)
quantitative milestones which are to be achieved every 3 years until
the area is redesignated attainment and which demonstrates reasonable
further progress, as defined in section 171(1), toward timely
attainment; and (4) either a demonstration (including air quality
modeling) that the plan will provide for attainment of the
PM10 NAAQS as expeditiously as practicable, but no later
than the end of the si
