Air Trends

Nitrogen Dioxide

National Trends in Nitrogen Dioxide Levels
Local Trends in Nitrogen Dioxide Levels

National Trends in Nitrogen Dioxide Levels

Using a nationwide network of monitoring sites, EPA has developed ambient air quality trends for nitrogen dioxide (NO2). Under the Clean Air Act, EPA sets and reviews national air quality standards for NO2. Air quality monitors measure concentrations of NO2 throughout the country. EPA, state, tribal and local agencies use that data to ensure that NO2 in the air is at levels that protect public health and the environment. Nationally, average NO2 concentrations have decreased substantially over the years. For information on NO2 standards, sources, health effects, and programs to reduce NO2, please see www.epa.gov/airquality/nitrogenoxides/.

Nitrogen dioxide air quality between 1980 and 2010, based on the annual arithmetic average. Chart shows a range of concentrations in 81 monitoring sites nationwide, with the average decreasing 52% from 1980 to 2010. Most of the sites have had concentrations below the national standard since the early 1980s.

Nitrogen dioxide air quality between 1980 and 2010, based on the annual arithmetic average. Chart shows a range of concentrations in 81 monitoring sites nationwide, with the average decreasing 52% from 1980 to 2010. Most of the sites have had concentrations below the national standard since the early 1980s.

How to Interpret the Graphs
View the chart data in Microsoft Excel (Download Excel Viewer)
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Nitrogen dioxide air quality between 1990 and 2010, based on the annual arithmetic average. Chart shows a range of concentrations in 150 monitoring sites nationwide, with the average decreasing 44% from 1990 to 2010.

How to Interpret the Graphs
View the chart data in Microsoft Excel (Download Excel Viewer)
View the chart data in HTML (New window opens)

Nitrogen dioxide air quality between 2000 and 2010, based on the annual arithmetic average. Chart shows a range of concentrations in 283 monitoring sites nationwide, with the average decreasing 34% from 2000 to 2010.

How to Interpret the Graphs
View the chart data in Microsoft Excel (Download Excel Viewer)
View the chart data in HTML (New window opens)

Local Trends in Nitrogen Dioxide Levels

Air quality trends can vary from one area to another. Local trends can be viewed at individual monitoring locations in the map below or in this KML file (KML, 303 KB) using Google Earth or another KML browser.

Nitrogen dioxide monitors that meet mimimum trends completeness criteria

Nitrogen dioxide monitors that have some data during the trend period but do not meet the mimimum trends completeness criteria

Nitrogen Dioxide

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