| (Ozone) Air Quality Classifications-
For the ozone National Ambient Air Quality Standard (NAAQS), an area's attainment status is defined by a classification:
- Extreme: The area has a design value of 0.187 ppm or above and has 20 years to attain.
- Severe 17: The area has a design value of 0.127.0.187 ppm and has 17 years to attain.
- Severe 15: The area has a design value of 0.120.0.127 ppm and has 15 years to attain.
- Serious: The area has a design value of 0.107.0.120 ppm and has nine years to attain.
- Moderate: The area has a design value of 0.092.0.107 ppm and has six years to attain.
- Marginal: The area has a design value of 0.085 up to 0.092 ppm and has three years to attain.
A plan to demonstrate how the nonattainment area expects to meet the National NAAQS by the deadline.
Measures to deal with air pollution. Examples of control strategies include an emissions trading program or vehicle inspection and maintenance.
eight-hour ozone standard-
The new indicator of air quality acceptability as it pertains to ground-level ozone. The current threshold value for this standard is 0.08 ppm, measured as maximum daily eight-hour average concentrations. To attain the ozone NAAQS, the three-year average of the annual fourth-highest daily maximum eight-hour ozone concentration must not exceed 0.08 ppm.
A geographic area that fails to meet a NAAQS. An area must be officially designated by the Environmental Protection Agency (EPA
), under procedures set forth by the Federal Clean Air Act (CAA), in order to be classified in nonattainment.
one-hour ozone standard-
The former indicator of air quality acceptability as it pertains to ground-level ozone. This indicator involves taking an average one-hour concentration of pollutants of a threshold of 0.12 parts per million (ppm). An area meets the ozone NAAQS if the monitored ozone level does not exceed the standard more than three times over a consecutive three-year period. The one-hour ozone standard was revoked effective June 15, 2005.