Area class Design value* Primary standard attainment date**
Marginal...... 0.121 up to 0.138...... 3 years after enactment
Moderate...... 0.138 up to 0.160...... 6 years after enactment
Serious....... 0.160 up to 0.180...... 9 years after enactment
Severe........ 0.180 up to 0.280...... 15 years after enactment
Extreme....... 0.280 and above........ 20 years after enactment
* The design value is measured in parts per million (ppm).
** The primary standard attainment date is measured from the date
of the enactment of the Clean Air Amendments of 1990.
"(2) Notwithstanding table 1, in the case of a severe area with a
1988 ozone design value between 0.190 and 0.280 ppm, the attainment
date shall be 17 years (in lieu of 15 years) after the date of the
enactment of the Clean Air Amendments of 1990.
"(3) At the time of publication of the notice under section
107(d)(4) (relating to area designations) for each ozone nonattainment
area, the Administrator shall publish a notice announcing the
classification of such ozone nonattainment area. The provisions of
section 172(a)(1)(B) (relating to lack of notice and comment and
judicial review) shall apply to such classification.
"(4) If an area classified under paragraph (1) (Table 1) would
have been classified in another category if the design value in the
area were 5 percent greater or 5 percent less than the level on which
such classification was based, the Administrator may, in the
Administrator's discretion, within 90 days after the initial
classification, by the procedure required under paragraph (3), adjust
the classification to place the area in such other category. In making
such adjustment, the Administrator may consider the number of
exceedances of the national primary ambient air quality standard for
ozone in the area, the level of pollution transport between the area
and other affected areas, including both intrastate and interstate
transport, and the mix of sources and air pollutants in the area.
"(5) Upon application by any State, the Administrator may extend
for 1 additional year (hereinafter referred to as the `Extension
Year') the date specified in table 1 of paragraph (1) of this
"(A) the State has complied with all requirements and
commitments pertaining to the area in the applicable
implementation plan, and
"(B) no more than 1 exceedance of the national ambient air
quality standard level for ozone has occurred in the area in
the year preceding the Extension Year.
No more than 2 one-year extensions may be issued under this paragraph
for a single nonattainment area.