(a) In accordance with section 181(a)(1) of the CAA, each area subject to Sec. 51.902(a) shall be classified by operation of law at the time of designation. However, the classification shall be based on the 8-hour design value for the area, in accordance with Table 1 below, or such higher or lower classification as the State may request as provided in paragraphs (b) and (c) of this section. The 8-hour design value for the area shall be calculated using the three most recent years of air quality data. For each area classified under this section, the primary NAAQS attainment date for the 8-hour NAAQS shall be as expeditious as practicable but not later than the date provided in the following Table 1.
Table 1--Classification for 8-Hour Ozone NAAQS for Areas Subject to Sec. 51.902(a)----------------------------------------------------------------------------------------------------------------
Maximum period for
attainment dates in
8-hour design state plans (years
Area class value (ppm after effective date of
ozone) nonattainment
designation for 8-hour
NAAQS)----------------------------------------------------------------------------------------------------------------Marginal................................. from........................ 0.085 3
up to \1\................... 0.092Moderate................................. from........................ 0.092 6
up to \1\................... 0.107Serious.................................. from........................ 0.107 9
up to \1\................... 0.120Severe-15................................ from........................ 0.120 15
up to \1\................... 0.127Severe-17................................ from........................ 0.127 17
up to \1\................... 0.187Extreme.................................. equal to.................... 0.187 20
or above....................----------------------------------------------------------------------------------------------------------------\1\ but not including.
(b) A State may request a higher classification for any reason in accordance with section 181(b)(3) of the CAA.
(c) A State may request a lower classification in accordance with section 181(a)(4) of the CAA.