June 8, 2021
The U.S. Environmental Protection Agency (EPA) released its annual interactive report tracking America’s progress in controlling air pollution since the passage of the Clean Air Act in 1970, announced by the EPA on May 26. “Our Nation’s Air: Trends Through 2020” documents the work EPA and its state, Tribal, community, and industry partners have done to achieve improvements in outdoor air quality across the country.
“The latest data in this report make clear once again that environmental protection and economic prosperity go hand in hand,” said EPA Administrator Michael S. Regan. “Dramatic reductions in air emissions continue to occur as the economy has grown significantly over the long term. To build on this progress, we still have important work to assure clean air for all Americans.”
EPA examines long-term trends to track the nation’s progress toward clean air. The report released today shows that, between 1970 and 2020, the combined emissions of six key pollutants dropped by 78 percent, while the U.S. economy remained strong – growing 272 percent over the same time.
In addition, national average concentrations of harmful air pollutants decreased considerably across our nation between 1990 and 2020:
• Carbon Monoxide (CO) 8-Hour, 73%
• Lead (Pb) 3-Month Average, 86% (from 2010)
• Nitrogen Dioxide (NO2) Annual, 61%
• Nitrogen Dioxide (NO2) 1-Hour, 54%
• Ozone (O3) 8-Hour, 25%
• Particulate Matter 10 microns (PM10) 24-Hour, 26%
• Particulate Matter 2.5 microns (PM2.5) Annual, 41% (from 2000)
• Particulate Matter 2.5 microns (PM2.5) 24-Hour, 30% (from 2000)
• Sulfur Dioxide (SO2) 1-Hour, 91%
Air quality concentrations can vary year to year, even as human-caused emissions continue to decline. Variations in weather, impacts of climate change, and events such as dust storms and wildfires can have an impact on air quality in affected areas. Many environmental impacts associated with climate change can affect the severity and timing of the wildfire season, including changes in temperature, precipitation, and drought.
Starting in mid-March 2020, many areas across the United States implemented stay-at-home restrictions in response to the COVID-19 pandemic. Schools, workplaces, and businesses were closed. As a result, vehicle travel significantly dropped, and we saw lower ambient concentrations of several pollutants including nitrogen dioxide (NO2) and ozone (O3) in many locations. Despite the drop in emissions, in some areas ozone levels, enhanced by weather conditions, increased.
Near the end of summer in 2020, the western United States experienced unprecedented wildfires over millions of acres. The significant wildfire activity and smoke led to poor visibility and very high concentrations of fine particle pollution across wide sections of the country. The increases in these areas had a small, but noticeable, impact on the national average concentrations of pollutants associated with fires – carbon monoxide and particle pollution.
The report includes interactive graphics that enable citizens, policymakers, and stakeholders to view and download detailed information by pollutant, geographic location and year. Explore the report and download graphics and data here: https://gispub.epa.gov/air/trendsreport/2021/