Skip to content U.S. Department of Transportation/Federal Highway AdministrationU.S. Department of Transportation/Federal Highway Administration

Office of Planning, Environment, & Realty (HEP)
PlanningEnvironmentReal Estate

HEP Events Guidance Publications Awards Contacts

Transportation Air Quality Facts and Figures January 2006

Nonattainment Areas

Classified 1-Hour Ozone Nonattainment Areas

December 2004

Map of the United States showing the counties that are designated as in non-attainment for the 1-Hour Ozone standard. Extreme and Severe are in red, including large parts of central California, the Houston, TX area, New Orleans, LA, Georgia, Illinois, Indiana, Wisconsin, the Washington DC area, and most of New Jersey with such a designation. Yellow depicts Serious classification on includes Phoenix, Dallas and parts of southern Texas near Houston, Connecticut, Massachusetts, Rhode Island, southern New Hampshire. Green is for Moderate and includes Cincinnati, parts of New Jersey, New York and Maine. Blue is for Marginal non-attainment areas and includes Seattle, parts of Nevada, areas in Pennsylvania, Delaware, New York and New Hampshire.

Areas that do not meet the NAAQS are designated as nonattainment areas. These areas must submit air quality plans, known as State Implementation Plans (SIPs), showing how they will attain the standards. If they do not meet these and other requirements, they face CAA required sanctions and other penalties, including loss of highway funds. Metropolitan Planning Organizations and the U.S. Department of Transportation must ensure that transportation plans, programs, and projects conform to these SIPs.

Ozone nonattainment areas were classified under the Clean Air Act Amendments of 1990 based on the severity of the air quality problem - from marginal to extreme - with expected attainment dates corresponding to the severity of the problem. Although most areas of the country now meet the 1-hour standard, many of our largest cities do not. This map shows ozone nonattainment areas under the 1-hour standard in 2004. EPA revoked the 1-hour standard in June 2005.

Source: U.S. Environmental Protection Agency. Greenbook: Nonattainment Areas for Criteria Pollutants.
Web site: http://www.epa.gov/oar/oaqps/greenbk/, 2 March 2005.
Note: Alaska, Hawaii, and U.S. Territories not shown.

Classified 8-Hour Ozone Nonattainment Ozone Areas

November 2004

Map of the United States showing the counties that are designated as in non-attainment for the 8-Hour Ozone standard. Severe areas are in black and include only Los Angles. Large parts of central California are in grey for Serious. Moderate areas are in blue and include the parts of California, Texas, Missouri, Illinois, Indiana, Wisconsin, Ohio, Delaware, New York, New Hampshire, and Maine, as well as the Washington DC area, and North Carolina. All of New Jersey, Connecticut, Massachusetts, and Rhode Island are blue. Yellow is for Marginal and includes parts of California, Texas, Louisiana, Tennessee, Arkansas, Virginia, Georgia, North Carolina, Indiana, Michigan and Pennsylvania. Green is for Subparts 1 and 2 and includes parts of California, Nevada, Arizona, Texas, Colorado, Alabama, Georgia, North and South Carolina, Tennessee, Kentucky, Wisconsin, Indiana, Michigan, Ohio, West Virginia, Pennsylvania, New York and Maine.

On April 15, 2004, EPA designated as 'nonattainment' the areas throughout the country that exceeded the 8-hour ozone health-based standard. To avoid 'backsliding,' or losing progress towards attaining the 8-hour ozone standard, specific control measures for the 1-hour standard may be required to stay in place until an area attains the 8-hour standard. The above map shows ozone nonattainment areas under the 8-hour standard in 2004.

The classification of 8-hour ozone nonattainment areas can range from Basic Subpart 1 Early Action Compact (EAC) with an 8-hour design value of up to .085 ppm ozone, to Extreme with an 8-hour design value equal to or above .187 ppm ozone.

Sources: U.S. Environmental Protection Agency. Greenbook: Nonattainment Areas for Criteria Pollutants.
Web site: http://www.epa.gov/oar/oaqps/greenbk/o8index.html 8 February 2005.
U.S. Environmental Protection Agency. Eight-Hour Ground-Level Ozone Designations Fact Sheet.
April 15, 2004. Web site: http://www.epa.gov/ozonedesignations/ 27 June 2005.
Classification for 8-Hour Ozone NAAQS. 40 CFR Part 51.903.
Note: Alaska, Hawaii, and U.S Territories are not shown.

Classified PM10 Nonattainment Areas

November 2004

Map of the United States showing the counties that are designated as in non-attainment for the PM10 standard. Serious areas are red include large parts of California, as well as parts of Nevada, Arizona, and Washington State. Yellow indicates Moderate areas of Arizona, New Mexico, Colorado, Utah, Idaho, Montana, Wyoming, Oregon, and Washington State.

This map shows that a majority of the PM10 nonattainment areas are located in the western half of the United States, where a dryer climate contributes to the formation of PM10 pollution.

Source: U.S. Environmental Protection Agency. Greenbook: Nonattainment Areas for Criteria Pollutants.
Web site: http://www.epa.gov/oar/oaqps/greenbk/mappm10.html 8 February 2005.
Note: Alaska, Hawaii, and U.S. Territories are not shown.

Classified PM2.5 Nonattainment Areas

December 2004

In December 2004, EPA designated 224 counties as nonattainment areas for PM2.5. The state and local governments have 3 years to develop implementation plans showing how they will meet the standard by reducing air pollutants that contribute to fine particle concentrations.

Source: U.S. Environmental Protection Agency. Greenbook: Nonattainment Areas for Criteria Pollutants.
Web site: http://www.epa.gov/pmdesignations/index.htm 8 February 2005.
Note: Alaska, Hawaii, and U.S. Territories are not shown.

Classified CO Nonattainment Areas

2004

Map of the United States showing the counties that are designated as in non-attainment for the CO standard. Serious areas are red including parts of California, Nevada, Arizona, Texas, and Washington State. Yellow and blue indicate Moderate areas of Utah, Nevada, and Montana, Wyoming. A small part of Oregon is green indicating not classified.

In 2004, none of the remaining CO nonattainment or maintenance areas reported any violations of the CO standard.

Source: U.S. Environmental Protection Agency. Greenbook: Nonattainment Areas for Criteria Pollutants.
Web site: http://www.epa.gov/airquality/greenbk/ 8 February 2005.
Note: Alaska, Hawaii, and U.S. Territories are not shown.

Updated: 07/06/2011
HEP Home Planning Environment Real Estate
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000