Overview of Environmental Indicators in EJScreen
EJScreen provides 13 environmental indicators:
| Key Medium | Indicator | Details | Source | Data Year |
|---|---|---|---|---|
| Air |
Particulate matter 2.5 (PM 2.5) |
Annual average PM2.5 levels in air | EPA's Office of Air and Radiation, fusion of modeled and monitored data | 2019 |
| Air | Ozone | Average of the annual top ten daily maximum 8-hour ozone concentrations in air | EPA's Office of Air and Radiation, fusion of modeled and monitored data | 2019 |
| Air | Diesel particulate matter | Diesel particulate matter level in air | EPA Hazardous Air Pollutants | 2019 |
| Air | Air toxics cancer risk | Lifetime cancer risk from inhalation of air toxics | EPA Hazardous Air Pollutants | 2019 |
| Air | Air toxics respiratory hazard index | Ratio of exposure concentration to health-based reference concentration | EPA Hazardous Air Pollutants | 2019 |
| Air | Toxic Releases to Air | RSEI modeled toxicity-weighted concentrations in air of TRI listed chemicals. | Calculated from 2021 Risk-Screening Environmental Indicators (RSEI) Geographic Microdata results for the air pathway, retrieved 5/16/2023 | 2021 |
| Air/other | 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 2020 U.S. Department of Transportation traffic data, retrieved 1/19/2023 | 2020 |
| Dust/ lead paint | Lead paint | Percent of housing units built pre-1960, as indicator of potential lead paint exposure | Calculated based on Census/American Community Survey (ACS) data, retrieved 2023 | 2017-2021 |
| Waste/ air/ water | Superfund proximity | 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 CERCLIS database, retrieved 11/23/2022 | 2022 |
| Waste/ air/ water | Risk management plan (RMP) facility proximity | 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 RMP database, retrieved 10/22/2022 | 2022 |
| Waste/ air/ water | Hazardous waste proximity | Count of hazardous waste facilities (TSDFs and LQGs) within 5 km (or nearest beyond 5 km), each divided by distance in kilometers | TSDF data calculated from EPA RCRAInfo database, retrieved 2/9/2023 | 2022 |
| Waste/ air/ water | Underground storage tanks (UST) and leaking UST (LUST) | Count of LUSTs (multiplied by a factor of 7.7) and the number of USTs within a 1,500-foot buffered block group | Calculated from EPA UST Finder, retrieved 2/2/2023 | 2022 |
| Water | Wastewater discharge | RSEI modeled toxic concentrations at stream segments within 500 meters, divided by distance in kilometers (km) | Calculated from RSEI modeled toxic concentrations to stream reach segments, created 11/23/2022 | 2020 |
Note: EJScreen’s EJ Indexes also include demographic information that is obtained from the U.S. Census Bureau’s American Community Survey (ACS). The EJScreen 2.2 version includes 2017-2021 ACS 5-year summary file data.
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, including documentation of data sources, in the EJScreen Technical Documentation (pdf) .
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. Other 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.