Days Exceeding NAAQ Standards for Fine Particulate Matter

This layer displays the percentage of days (in a single year) with the concetration of fine particulate matter (fine particles 2.5 micrometers or less) above the National Ambient Air Quality Standard (NAAQS) of 35.0 micrograms per cubic meter.

Days Exceeding NAAQ Standards for Ozone

This layer displays the percentage of days (in a single year) with the maximum 8-hour average ozone concetration above the National Ambient Air Quality Standard (NAAQS) of 0.070 parts per million.

Air Toxics – Non-Cancer Risk by Census Tract

Layer displays the modeled non-cancer risk associated with air toxics exposure. A hazard index (HI) of 1 or lower means air toxics are unlikely to cause adverse noncancer health effects over a lifetime of exposure.

Air Facility System Sites

This layer displays the locations of regulated facilities that discharge air pollutants in the United States. The Air Facility System (AFS) contains compliance and permit data for stationary sources of air pollution (such as electric power plants, steel mills, factories, … Continued

Air Quality System Sites

This layer displays the locations of air quality monitoring stations in the United States. The Air Quality System (AQS) contains ambient air pollution data collected by EPA, state, Local, and tribal air pollution control agencies from thousands of monitoring stations. … Continued