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 Selected Facts and Figures

Nonattainment and Maintenance Areas

Am I Living in a Nonattainment Area?

The maps on the following pages show the nonattainment areas for the various pollutants. Additional information can be found in the Green Book on EPA's website at https://www3.epa.gov/airquality/greenbk/.

Where Are the Ozone Nonattainment Areas?

On October 26, 2015, EPA adopted a more stringent 8-hour ozone health-based standard of 0.070 ppm. EPA will designate in 2017 both new nonattainment classification ranges and those areas that exceed the 2015 standard. To avoid backsliding, or losing progress toward attaining the 8-hour ozone standard, specific control measures for the previous 1-hour standard may be required to stay in place until an area attains the 8-hour standard.

The map below shows the ozone nonattainment areas designated under the older 2008 8-hour standard of 0.075 ppm. The classification of 8-hour ozone nonattainment areas can range from marginal with an 8-hour design value of up to 0.086 ppm O3, to extreme with an 8-hour design value equal to or above 0.175 ppm O3.

Ozone Nonattainment Areas (January 2015)

Title: Map of continental United States showing ozone nonattainment areas as of January 2015 - Description: The map shows the ozone nonattainment areas in the United States designated under the older 2008 8-hour standard of 0.075 ppm. The classification of 8-hour ozone nonattainment areas can range from Marginal with an 8-hour design value of up to 0.086 ppm ozone to Extreme with an 8-hour design value equal to or above 0.175 ppm ozone. All of the Extreme through Serious areas are found in California, while Marginal areas exist around many major metropolitan areas throughout the country.

Source: U.S. Environmental Protection Agency, Green Book, January 2015, https://www3.epa.gov/airquality/greenbook/map8hr_2008.html

Where Are the PM10 Nonattainment Areas?

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 greater PM10 pollution.

PM10 Nonattainment Areas (January 2015)

Title: Map of the PM-10 Nonattainment Areas in the United States as of January 2015 - Description: The map shows the PM-10 nonattainment areas in the United States as of January 2015. The majority of the PM-10 nonattainment areas are located in the western half of the United States, where a dryer climate contributes to the formation of greater PM-10 pollution.

Source: U.S. Environmental Protection Agency, Green Book, January 2015, https://www3.epa.gov/airquality/greenbk/mapPM10.html

Where Are the PM2.5 Nonattainment Areas?

This map shows that a majority of the PM2.5 nonattainment areas are located in the western half of the United States and in industrial areas in the east.

Counties Designated Nonattainment for PM2.5

(October 2015)

Title: Map of PM-2.5 nonattainment areas in the United States as of October 2015 - Description: The map shows the PM-2.5 nonattainment areas in the United States as of October 2015. The majority of the PM-2.5 nonattainment areas are located in the western half of the United States and in industrial areas in the east.

Nonattainment areas are indicated by color. When only a portion of a county is shown in color, it indicates that only that part of the county is within a nonattainment area boundary

Source: U.S. Environmental Protection Agency, Green Book, October 2015, https://www3.epa.gov/airquality/greenbook/mappm25both.html

Where Are the CO Nonattainment Areas?

As of September 2010, all CO areas have been redesignated to maintenance areas. Great progress has been made in reducing CO emissions since 1970.

Where Are the NO2 Nonattainment Areas?

Los Angeles-South Coast Air basin was redesignated to a NO2 maintenance area in 1998. All other areas of the country presently meet the current NO2 NAAQS, with annual concentrations well below the level of the standard (53 ppb). Annual average ambient NO2 concentrations have decreased by more than 40 percent since 1980.

Updated: 5/4/2016
HEP Home Planning Environment Real Estate
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000