EPA Environmental Data and FIPS Geography

The Environmental Protection Agency publishes a wide range of geographic datasets using county FIPS codes as the primary identifier. The most commonly used are the Air Quality System (AQS) database, the Toxics Release Inventory (TRI), the Safe Drinking Water Information System (SDWIS), and the EJSCREEN environmental justice mapping tool. Our federal datasets guide provides an overview of all major federal data producers including the EPA.

The Air Quality System contains monitoring station data for criteria pollutants (PM2.5, ozone, NO2, etc.) going back to the 1980s. Each monitoring site is identified by a composite code — State Code + County Code + Site Number — where the state and county codes are the FIPS components. To find all monitors in King County, WA, filter for state code 53 and county code 033. The county-level annual summary files aggregate this to a single value per county, directly joinable to Census and BLS data via the 5-digit FIPS code.

EJSCREEN, the EPA's environmental justice screening tool, publishes data at the Census block group level — identifiable by an 11-digit GEOID (state + county + tract + block group). For county-level aggregations, you'll need to aggregate block group data after joining on the first 5 digits of the GEOID. This is a common pattern when working with sub-county EPA data.

The TRI (Toxics Release Inventory) reports emissions by facility, with each facility geocoded to a county. The download files include a separate state and county FIPS field that you concatenate to form the 5-digit code. Researchers studying pollution burden by geography routinely join TRI data with Census demographic data using county FIPS codes. Use the county search or individual county pages like Los Angeles (06037) to identify the FIPS codes you need before pulling data.