Nonattainment area

{
  "id": "MLC-T-ENV-018757",
  "term": "Nonattainment area",
  "field": "Environment",
  "term_source": "Nonattainment Area",
  "definitions": [
    "1. A nonattainment area is a region in which the level of a criteria air pollutant is higher than allowed by the federal NAAQS. For ground-level ozone, the one-hour standard is 120 parts per billion. EPA puts a city or metropolitan area on its \"nonattainment\" list when ozone exceeds, or violates, the standard more than once a year averaged over a three-year period.\n\n2. A geographic area that fails to meet, for a specified criteria pollutant, the National Ambient Air Quality Standards.\n\n3. A geographic area in which the level of a criteria air pollutant is higher than the level allowed by the federal standards. A single geographic area may have acceptable levels of one criteria air pollutant but unacceptable levels for one or more other criteria air pollutants. Thus, an area could be both attainment and nonattainment at the same time. It has been estimated that 60% of Americans live in nonattainment areas.\n\n4. Any area of the country designated by the EPA at 40 CFR part 81 in accordance with section 107(d) of the Act as nonattainment for one or more criteria pollutants. An area could be a nonattainment area for some pollutants and an attainment area for other pollutants.\n\n5. Any geographic region of the United States which has been designated as nonattainment under section 107 of the CAA for any pollutant for which a national ambient air quality standard exists.\n\n6. Area designated as nonattainment under section 107 of the Act and described in 40 CFR part 81.\n\n7. Geographic area that does not meet one or more of the federal air quality standards (NAAQS) for the criteria pollutants.\n\n8. If the air quality in a geographic area meets or is cleaner than the National Ambient Air Quality Standard (NAAQS), it is called an attainment area; areas that don't meet the national standard are called nonattainment areas. In some cases, EPA is not able to determine an area's status after evaluating the available information and those areas are designated \"unclassifiable.\" These are areas that do not meet (or that contributes to ambient air quality in a nearby area that does not meet) the national primary or secondary ambient air quality standard for a NAAQS.\n\n9. An area designated as nonattainment under section 107 of the Act and described in 40 CFR part 81.",
    "If the air quality in a geographic area meets or is cleaner than the National Ambient Air Quality Standard (NAAQS), it is called an attainment area; areas that don't meet the national standard are called nonattainment areas. In some cases, EPA is not able to determine an area's status after evaluating the available information and those areas are designated \"unclassifiable.\" These are areas that do not meet (or that contributes to ambient air quality in a nearby area that does not meet) the national primary or secondary ambient air quality standard for a NAAQS."
  ],
  "abbreviation": "NAA",
  "subject": [
    "Locations",
    "Health and safety"
  ],
  "references": [
    "Heat Island Effect Glossary",
    "Emissions Inventory System Glossary",
    "Air Permitting Terms",
    "40 CFR 51.491 (CFR 2018)",
    "40 CFR 93.101 (CFR 2018)",
    "40 CFR 93.152 (CFR 2018)",
    "Basic Concepts in Environmental Sciences",
    "Glossary of EJSCREEN Terms",
    "General Conformity Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/nonattainment-area/"
}