Using a nationwide network of monitoring sites, EPA has developed ambient air quality trends for particle pollution, also called Particulate Matter (PM). Under the Clean Air Act, EPA sets and reviews national air quality standards for PM. Air quality monitors measure concentrations of PM throughout the country. EPA, state, tribal and local agencies use that data to ensure that PM in the air is at levels that protect public health and the environment. Nationally, average PM concentrations have decreased over the years. For information on PM standards, sources, health effects, and programs to reduce PM, please see www.epa.gov/airquality/particlepollution.
Air quality trends can vary regionally. The following climatically consistent regions within the contiguous United States provide a relevant way to look at regional trends in air quality. [Need to work on this text.]
Air quality trends can vary from one area to another. Local trends can be viewed at individual monitoring locations in the maps below or in this PM10 KML file (KML, 1 MB) or this PM2.5 KML file (KML, 546 KB) using Google Earth or another KML browser.PM10 monitors that meet mimimum trends completeness criteria
PM10 monitors that have some data during the trend period but do not meet the mimimum trends completeness criteria
PM2.5 monitors that meet mimimum trends completeness criteria
PM2.5 monitors that have some data during the trend period but do not meet the mimimum trends completeness criteria