The following HTML text is provided to enhance online
readability. Many aspects of typography translate only awkwardly to HTML.
Please use the page image
as the authoritative form to ensure accuracy.
Air Quality Management in the United States
Attainment. Any area that meets the national primary and secondary ambient air quality standard for the pollutant and does not contribute to the violation of a national primary or secondary ambient air quality standard in a nearby area.
Unclassifiable. Any area that cannot be classified on the basis of available information as meeting or not meeting a national primary or secondary ambient air quality standard for the pollutant.
The CAA further classifies O3 nonattainment areas as marginal, moderate, serious, severe, and extreme, and CO nonattainment areas as moderate or serious (see Table 3-1). The procedures used to determine the appropriate designation and classification for an area are described in Box 3-2.
The basic requirements for states in general and for those areas that are in nonattainment of one or more NAAQS are listed in Box 3-3. The requirements for a SIP grow in stringency and complexity as an area’s designation shifts from attainment to nonattainment and, for ozone (O3) and carbon monoxide (CO), to the more acute nonattainment classifications. Because the major efforts in air quality management (AQM) for criteria
TABLE 3-1 Classification of Nonattainment Areas for O3 and CO Mandated in the CAA Amendments of 1990
aThe primary standard attainment date for O3 is determined from the date of the enactment of the CAA Amendments of 1990.
bThe classification scheme for O3 was devised by Congress before EPA promulgated a new 8-hr standard, and, thus, the classification relates to the old 1-hr form of the standard.
cThe requirements for severe-15 and severe-17 O3 nonattainment areas are the same except for the attainment dates.
dModerate CO nonattainment areas with design values of 12.7 ppm or less have reduced SIP requirements compared with those areas with design values above 12.7 ppm.
eThese values for CO refer to a rolling 8-hr average. Abbreviation: ppm, parts per million.
Items in cart [0]
