Title 18 . Environmental Conservation

Chapter 50 . Administrative Enforcement

Section 20. Baseline dates and maximum allowable increases

18 AAC 50.020. Baseline dates and maximum allowable increases

(a) In an area designated nonattainment in 18 AAC 50.015(b) , the provisions of this section do not apply to the nonattainment air pollutant. However, this section does apply to all other air pollutants listed in Table 2 in this subsection.

Table 2

Baseline Dates

Air Quality control Air Pollutant Baseline Date Region Cook Inlet Intrastate Air Nitrogen dioxide February 8, 1988 Quality Control Region Sulfur dioxide October 12, 1979 PM-10 March 20, 1982 Northern Alaska Intrastate Air Nitrogen dioxide February 8, 1988 Quality Control Sulfur dioxide June 1, 1979 Region PM-10 November 13, 1978 South Central Alaska Nitrogen dioxide February 8, 1988 Intrastate Air Quality Sulfur dioxide October 26, 1979 Control Region PM-10 October 26, 1979 Southeast Alaska Intrastate Air Nitrogen dioxide February 8, 1988 Quality Control Region Sulfur dioxide November 10, 1986 PM-10 The earliest date upon which the department declares complete an application for a facility or modification that includes information required under 18 AAC 50.306 and shows an increase in actual PM-10 emissions equal to or exceeding 15 tons per year.

(b) To establish standards for the prevention of significant deterioration of air quality,

(1) baseline dates for determining the ambient concentration of certain air pollutants are established for each air quality control region listed in Table 2 in (a) of this section;

(2) in areas designated as Class I, II, or III, increases in air pollutant concentration over the baseline concentration shall be limited to the concentrations in Table 3 in this subsections;

(3) 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; and

(4) the baseline concentrations and maximum allowable increases shall be measured or predicted by a method described in 18 AAC 50.215.

Table 3

Maximum Allowable Increases

Classification of area Maximum allowable in 18 AAC 50.015(c) Air Pollutant increase (micrograms Table 1 per cubic meter) PM-10: Annual arithmetic mean ..... ................... 4 24-hour maximum ............ ................... 8 Sulfur Dioxide: CLASS I Annual arithmetic mean ..... ................... 2 24-hour maximum ............ ................... 5 3-hour maximum ............. .................. 25 Nitrogen Dioxide: Annual arithmetic mean ..... ................. 2.5 PM-10: Annual arithmetic mean ..... .................. 17 24-hour maximum ............ .................. 30 Sulfur Dioxide: CLASS II Annual arithmetic mean ..... .................. 20 24-hour maximum ............ .................. 91 3-hour maximum ............. ................. 512 Nitrogen Dioxide: Annual arithmetic mean ..... .................. 25 PM-10: Annual arithmetic mean ..... .................. 34 24-hour maximum ............ .................. 60 Sulfur Dioxide: CLASS III Annual arithmetic mean ..... .................. 40 24-hour maximum ............ ................. 182 3-hour maximum ............. ................. 700 Nitrogen Dioxide: Annual arithmetic mean ..... ................... 50

(c) Repealed 10/1/2004.

(d) Repealed 10/1/2004.

(e) For purposes of this section, the baseline concentration of an air pollutant is determined as follows:

(1) for PM-10 and sulfur dioxide, the baseline concentration is the ambient concentration of the air pollutant on the applicable baseline date, plus the contribution from allowable emissions of a PSD major stationary source for which construction commenced before January 6, 1975, but that was not in operation by the baseline date; however, the baseline concentration does not include actual emissions from a PSD major stationary source or a PSD major modification for which construction commenced on or after January 6, 1975; and

(2) for nitrogen dioxide, the baseline concentration is the ambient concentration of the air pollutant on the applicable baseline date, plus the contribution from allowable emissions of a PSD major stationary source for which construction commenced before February 8, 1988, but that was not in operation by the baseline date.

(f) In this section "commence" has the meaning given in 40 C.F.R. 52.21(b), adopted by reference in 18 AAC 50.040.

History: Eff. 1/18/97, Register 141; am 6/21/98, Register 146; am 10/1/2004, Register 171

Authority: AS 46.03.020

AS 46.14.010

AS 46.14.030