PM2.5 Data Omitted from Trends Assessment
Through a combination of regularly scheduled technical systems audits of non-EPA laboratories processing state PM2.5 monitoring data and additional assessments of data quality, EPA has identified data quality issues that affect Illinois, most of Tennessee and parts of Kentucky. EPA has made a preliminary determination that this data should not be used for regulatory purposes. Until a final determination has been made, EPA has moved the data in the Air Quality System database for the PM2.5 sites in question from parameter code 88101 (PM2.5 at local conditions; used for regulatory data) to parameter code 88501 (PM2.5 raw data). This change will clarify to data users that data from these sites should not be compared to the PM2.5 National Ambient Air Quality Standards until EPA has made a final validity determination. This data is not included in the PM2.5 trends assessment or summary tables on this website.
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.
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