9VAC5-80-1635. Ambient air increments

In areas designated as class I, II or III, increases in pollutant concentration over the baseline concentration shall be limited to the following: MAXIMUM ALLOWABLE INCREASE (micrograms per cubic meter) MAXIMUM ALLOWABLE INCREASE (micrograms per cubic meter) Class I Area Class I Area PM 2.5 : PM 2.5 : Annual arithmetic mean 1 Annual arithmetic mean 1 24 hour maximum 2 24 hour maximum 2 PM 10 : PM 10 : Annual arithmetic mean 4 Annual arithmetic mean 4 24 hour maximum 8 24 hour maximum 8 Sulfur dioxide: Sulfur dioxide: Annual arithmetic mean 2 Annual arithmetic mean 2 24-hour maximum 5 24-hour maximum 5 Three-hour maximum 25 Three-hour maximum 25 Nitrogen dioxide: Nitrogen dioxide: Annual arithmetic mean 2.5 Annual arithmetic mean 2.5 Class II Area Class II Area PM 2.5 : PM 2.5 : Annual arithmetic mean 4 Annual arithmetic mean 4 24 hour maximum 9 24 hour maximum 9 PM 10 : PM 10 : Annual arithmetic mean 17 Annual arithmetic mean 17 24 hour maximum 30 24 hour maximum 30 Sulfur dioxide: Sulfur dioxide: Annual arithmetic mean 20 Annual arithmetic mean 20 24-hour maximum 91 24-hour maximum 91 Three-hour maximum 512 Three-hour maximum 512 Nitrogen dioxide: Nitrogen dioxide: Annual arithmetic mean 25 Annual arithmetic mean 25 Class III Area Class III Area PM 2.5 : PM 2.5 : Annual arithmetic mean 8 Annual arithmetic mean 8 24 hour maximum 18 24 hour maximum 18 PM 10 : PM 10 : Annual arithmetic mean 34 Annual arithmetic mean 34 24 hour maximum 60 24 hour maximum 60 Sulfur dioxide: Sulfur dioxide: Annual arithmetic mean 40 Annual arithmetic mean 40 24-hour maximum 182 24-hour maximum 182 Three-hour maximum 700 Three-hour maximum 700 Nitrogen dioxide: Nitrogen dioxide: Annual arithmetic mean 50 Annual arithmetic mean 50 For any period other than an annual period, the applicable maximum allowable increase may be exceeded during one such period per year at any one location.