Ozone Pollution Has Decreased Only Slightly During The Pandemic

Car traffic across the country is down about 40%, but ozone pollution has barely decreased compared with levels over the past five years. Factories, refineries, power plants and diesel trucks are still dominant sources of pollution in many places.

Percent change in median ozone levels, 2020 compared with 2015-2019

Pittsburgh area

8.9% less ozone

Los Angeles area

14% less ozone

Houston area

11.9% less ozone

Notes

The areas shown in color represent 335 out of 929 core-based statistical areas (CBSA) in the United States, which are one or more counties, anchored by an urban center of 10,000 people or more. Areas in white are either CBSAs with no available data, too little data or areas outside of CBSAs. Places where ozone increased in 2020 had low ozone levels between 2015 and 2019.