Ohio Administrative Code
Title 3745 - Ohio Environmental Protection Agency
Chapter 3745-25 - Emergency Episode Standards
Section 3745-25-03 - Air pollution emergencies and episode criteria

Universal Citation: OH Admin Code 3745-25-03

Current through all regulations passed and filed through December 16, 2024

The purpose of rules 3745-25-02 to 3745-25-05 of the Administrative Code is to prevent the excessive buildup of air contaminants during air pollution episodes, thereby preventing the occurrence of an emergency due to the effects of these air contaminants on the health of persons.

(A) Conditions justifying the proclamation of an air pollution "Alert", air pollution "Warning", or air pollution "Emergency" are deemed to exist whenever the director determines that the accumulation of air contaminants in any place is attaining or has attained levels which could, if such levels are sustained or exceeded, lead to a substantial threat to the health of persons. In making this determination, the director will be guided by the episode stage criteria in paragraphs (B) to (F) of this rule.

(B) "Air pollution forecast": An internal watch by the Ohio environmental protection agency will actuated by a national weather service advisory that an "Atmospheric Stagnation Advisory" is in effect or the equivalent local forecast of stagnant atmospheric condition. The air pollution forecast for photochemical oxidants takes into consideration, but not be limited to, ambient temperatures, surface winds, and ultra-violet solar radiation levels.

(C) "Alert": The "Alert" level is that concentration of air contaminants at which first stage control actions are to begin. An "Alert" will be declared when any one of the following levels is reached at any monitoring site and meteorological conditions are such that the air contaminant concentrations can be expected to remain at the specified level or reoccur during the next twenty-four hours unless control actions are taken:

(1) Sulfur dioxide: eight hundred micrograms per cubic meter (0.3 parts per million by volume), twenty-four-hour average.

(2) PM10: three hundred fifty micrograms per cubic meter, twenty-four-hour average.

(3) Carbon monoxide: seventeen milligrams per cubic meter (fifteen parts per million by volume), eight-hour average;.

(4) Photochemical oxidants measured as ozone: four hundred micrograms per cubic meter (0.2 parts per million by volume), one-hour average.

(5) Nitrogen dioxide.
(a) One thousand thirty micrograms per cubic meter (0.6 parts per million by volume), one-hour average.

(b) Two hundred eighty-two micrograms per cubic meter (0.15 parts per million by volume), twenty-four-hour average.

(D) "Warning": The "Warning" level indicates that air quality is continuing to degrade and that additional control measures are necessary. A "Warning" will be declared when any one of the following levels is reached at any monitoring site and meteorological conditions are such that the air contaminant concentrations can be expected to remain at the specified levels or reoccur during the next twenty-four hours unless control actions are taken:

(1) Sulfur dioxide: one thousand six hundred micrograms per cubic meter (0.6 parts per million by volume), twenty-four-hour average.

(2) PM10: four hundred twenty micrograms per cubic meter, twenty-four-hour average.

(3) Carbon monoxide: thirty-four milligrams per cubic meter (thirty parts per million by volume), eight-hour average.

(4) Photochemical oxidants measured as ozone: eight hundred micrograms per cubic meter (0.4 parts per million by volume), one-hour average.

(5) Nitrogen dioxide.
(a) Two thousand two hundred sixty micrograms per cubic meter (1.2 parts per million by volume), one-hour average.

(b) Five hundred sixty-five micrograms per cubic meter (0.3 parts per million by volume), twenty-four-hour average.

(E) "Emergency": The "Emergency" level indicates that air quality is continuing to degrade to a level that should never be reached and that the most stringent control actions are necessary. An "Emergency" will be declared when any one of the following levels is reached at any monitoring site:

(1) Sulfur dioxide: two thousand one hundred micrograms per cubic meter (0.8 parts per million by volume), twenty-four-hour average.

(2) PM10: five hundred micrograms per cubic meter, twenty-four-hour average.

(3) Carbon monoxide: forty-six milligrams per cubic meter (forty parts per million by volume); eight-hour average.

(4) Photochemical oxidants measured as ozone: One thousand micrograms per cubic meter (0.5 parts per million by volume), one-hour average.

(5) Nitrogen dioxide.
(a) Three thousand micrograms per cubic meter (1.6 parts per million by volume), one-hour average.

(b) Seven hundred fifty micrograms per cubic meter (0.4 parts per million by volume), twenty-four-hour average.

(F) "Termination": Once declared, any episode stage reached by application of these criteria will remain in effect until the criteria for that episode stage are no longer met. At such time, the next lower episode stage will be assumed or the episode may be terminated completely if no episode stage criteria are met.

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