EJSCREEN: Environmental Justice Screening and Mapping Tool

Overview of Environmental Indicators in EJSCREEN

EJSCREEN provides 11 environmental indicators:

Summary Table of Environmental Indicators and Data Sources
Key Medium Indicator Details Source Data Year


National-Scale Air Toxics Assessment (NATA) air toxics cancer risk

Lifetime cancer risk from inhalation of air toxics




NATA respiratory hazard index

Air toxics respiratory hazard index (ratio of exposure concentration to health-based reference concentration)




NATA diesel PM

Diesel particulate matter level in air, µg/m3




Particulate matter

PM2.5 levels in air, µg/m3 annual avg.

EPA, Office of Air and Radiation (OAR) fusion of model and monitor data




Ozone summer seasonal avg. of daily maximum 8-hour concentration in air in parts per billion

EPA, OAR fusion of model and monitor data



Traffic proximity and volume

Count of vehicles (AADT, avg. annual daily traffic) at major roads within 500 meters, divided by distance in meters (not km)

Calculated from 2014 U.S. Department of Transportation (DOT) traffic data, retrieved 2016


Dust/ lead paint

Lead paint indicator

Percent of housing units built pre-1960, as indicator of potential lead paint exposure

Calculated based on Census/American Community Survey (ACS) data, retrieved 2015


Waste/ air/ water

Proximity to Risk Management Plan (RMP) sites

Count of RMP (potential chemical accident management plan) facilities within 5 km (or nearest one beyond 5 km), each divided by distance in kilometers

Calculated from EPA's RMP database, retrieved 12/01/2015


Waste/ air/ water

Proximity to Treatment Storage and Disposal Facilities (TSDFs)

Count of TSDFs (hazardous waste management facilities) within 5 km (or nearest beyond 5 km), each divided by distance in kilometers

Calculated from EPA's Resource Conservation and Recovery Act (RCRA) Info database, retrieved 08/16/2016


Waste/ air/ water

Proximity to National Priorities List (NPL) sites

Count of proposed or listed NPL - also known as superfund - sites within 5 km (or nearest one beyond 5 km), each divided by distance in kilometers

Calculated from EPA's Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS) database, retrieved 10/30/2015



Proximity to major direct water dischargers

Count of National Pollutant Discharge Elimination System (NPDES) major direct water discharger facilities within 5 km (or nearest one beyond 5 km), each divided by distance in kilometers

Calculated from EPA's Permit Compliance System/ Integrated Compliance Information System (PCS/ICIS) database, retrieved 11/30/2015


Note: EJSCREEN’s EJ Indexes also include demographic information that is obtained from the U.S. Census Bureau’s American Community Survey (ACS). The 2016 version of EJSCREEN includes 2010-2014 ACS 5-year summary file data, which is based on 2012 Census boundaries.

It is important to understand what each of these is measuring or indicating, in order to use EJSCREEN appropriately. There are important caveats and limitations to these screening-level indicators and anyone using EJSCREEN is encouraged to read these carefully.

Read more information about Environmental Indicators (PDF)(123 pp, 1 MB, About PDF), including documentation of data sources.

Some of these environmental indicators quantify proximity to and the numbers of certain types of potential sources of exposure to environmental pollutants, such as nearby hazardous waste sites or traffic. The lead paint indicator indicates the presence of older housing, which often, but not always, indicates the presence of lead paint, and therefore the possibility of exposure. In some cases, the term "exposure" is used very broadly here to refer to the potential for exposure. Others indicators in EJSCREEN are estimates of ambient levels of air pollutants, such as PM2.5, ozone and diesel particulate matter. Still others are actual estimates of air toxics-related cancer risk or a hazard index, which summarizes the ratios of ambient air toxics levels to health-based reference concentrations. In other words, these environmental indicators vary widely in what they indicate.

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