Daily summary of air quality at specified locations in King County (Nitrogen Dioxide). 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. The charts below show national and regional trends in NO2 concentrations.

Daily summary of air quality at specified locations in King County (Lead). Air quality monitors measure concentrations of lead throughout the country. EPA, state, tribal and local agencies use those data to ensure that lead is at levels that protect public health and the environment. EPA has tracked air quality trends for lead using data from this network of monitors. Nationally, average lead concentrations decreased dramatically after EPA's regulations reduced the lead content in on-road motor vehicle gasoline.

Daily summary of air quality at specified locations in King County (Sulfer Dioxide). Air quality monitors measure concentrations of SO2 throughout the country. EPA, state, tribal and local agencies use that data to ensure that SO2 in the air is at levels that protect public health and the environment. Nationally, average SO2 concentrations have decreased substantially over the years. The charts below show national and regional trends in SO2 concentrations.

Daily summary of air quality at specified locations in King County (Particulate Matter - PM2.5 LC). Using a nationwide network of monitoring sites, EPA has developed ambient air quality trends for particle pollution, also called Particulate Matter (PM). PM2.5 describes fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller. 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 PM2.5 concentrations have decreased over the years.

Daily summary of air quality at specified locations in King County (Carbon Monoxide). Air quality monitors measure concentrations of CO throughout the country. EPA, state, tribal and local agencies use that data to ensure that CO remains at levels that protect public health and the environment. Nationally, average CO concentrations have decreased substantially over the years. The charts below show national and regional trends in CO concentrations.

Daily summary of air quality at specified locations in King County (Ozone). Air quality monitors measure concentrations of ozone throughout the country. EPA, state, tribal and local agencies use that data to ensure that ozone is at levels that protect public health and the environment. Nationally, average ozone levels declined in the 1980's, leveled off in the 1990's, and showed a notable decline after 2002. The charts below show national and regional trends in ozone concentrations.

Daily summary of air quality at specified locations in King County (Particulate Matter - PM10). PM10 describes inhalable particles, with diameters that are generally 10 micrometers and smaller. 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 PM10 concentrations have decreased over the years.