Conditions justifying the declaration of a forecast will be deemed to exist whenever the Department determines that the meteorological conditions are such that the ambient air contaminant concentrations in any part of an air quality control region may be expected to substantially increase above normal levels. Conditions justifying the declaration of an alert, warning or emergency will be deemed to exist whenever the Department determines that the concentration of ambient air contaminants in a part of an air quality control region is attaining or has attained levels which could, if the levels are sustained or exceeded, lead to a substantial threat to the health of persons. In making the determinations, the Department will consider the following:

1. (1) Forecast level. A forecast will be declared when meteorological conditions are such that ambient air contaminant concentrations may be expected to increase substantially above normal levels.

2. (2) Alert level. An alert should be declared when one or more of the following levels is reached at a designated air quality monitoring facility and meteorological conditions are such that pollutant concentrations may be expected to remain at the level for 12 or more hours or increase unless control actions are taken:

   1. (i) SO₂—0.3 p.p.m., 6-hour average.
   2. (ii) PM₁₀—350 µg/m³ , 24-hour average.
   3. (iii) Ozone—0.2 p.p.m., 1-hour average.
   4. (iv) NO₂—0.15 p.p.m., 24-hour average; 0.6 p.p.m., 1-hour average.

3. (3) Warning level. A warning should be declared when one or more of the following levels is reached at a designated air quality monitoring facility and meteorological conditions are such that pollutant concentrations may be expected to remain at the level for 12 or more hours or increase unless control actions are taken:

   1. (i) SO₂—0.6 p.p.m., 6-hour average.
   2. (ii) PM₁₀—420 µg/m³ , 24-hour average.
   3. (iii) CO—30 p.p.m., 8-hour average.
   4. (iv) Ozone—0.4 p.p.m., 1-hour average.
   5. (v) NO₂—0.3 p.p.m., 24-hour average; 1.2 p.p.m., 1-hour average.

4. (4) Emergency level. An emergency should be declared when one or more of the following levels is reached at a designated air quality monitoring facility and meteorological conditions are such that this level can be expected to continue for 12 or more hours:

   1. (i) SO₂—0.8 p.p.m., 24-hour average.
   2. (ii) PM₁₀—500 µg/m³ , 24-hour average.
   3. (iii) CO—40 p.p.m., 8-hour average.
   4. (iv) Ozone—0.5 p.p.m., 1-hour average.
   5. (v) NO₂—0.4 p.p.m., 24-hour average; 1.6 p.p.m., 1-hour average.
5. (5) Termination. Once declared, any level reached in accordance with these criteria should remain in effect until the criteria for the alert level are no longer met and meteorological conditions are such that pollutant concentrations may be expected to decrease.

Source

The provisions of this § 137.3 adopted January 27, 1972, effective January 28, 1972, 2 Pa.B. 383; amended November 12, 1976, effective November 13, 1976, 6 Pa.B. 2881; amended June 8, 1990, effective June 9, 1990, 20 Pa.B. 3060. Immediately preceding text appears at serial pages (105249) to (105250) and (136435).