The Superfund proximity indicator is reflective of the total count of sites proposed and listed (final) on
the National Priorities List (NPL) in each block group within 5 km of the average resident in a block
group, divided by distance, calculated as the population-weighted average of blocks in each block group.
The ozone indicator in EJScreen reflects potential ozone exposure measured in terms of summer
seasonal daily average maximum concentrations in an 8-hour period measured in parts per billion.
Ozone information included in EJScreen highlights areas across the U.S. that are not meeting the
national ambient air quality standard for ozone. In other words, the levels of ozone present in these
areas are deemed harmful to human health.
The ozone indicator in EJScreen is a measure of potential exposure but not a measure of risk. The raw
ozone data is compiled by census tract, which is supplied for use in the tool by EPA’s OAQPS. For air
toxics risk measures (as opposed to exposure) users can turn to EJScreen’s other three indicators: cancer
risk, respiratory HI, and diesel PM.
The air toxics respiratory HI indicator is the respiratory HI from the analyzed carcinogens in ambient
outdoor air, as provided by the 2017 Air Toxics Data Update. The data is reported at the Census tract
level. Block group level values are assigned by repeating each parent tract level value.
This layer displays the number of threatened and endangered species in each county. Additional layers are available for the type of species, such as plants, animals, invertebrates, and more!
View in Map RoomThis layer displays the percentage of weeks in any severity of drought for the years 2021-2023.
View in Map RoomThis US EPA feature layer is updated hourly and reflects the latest hour of air quality data received from each monitoring site that reports to AirNow. The concentration and AQI values are for Ozone and Particulate Matter (PM) only. Air quality index ranges from 0-5,000 with higher values indicating worse air quality.
View in Map RoomThis layer displays areas that experienced dry or drought conditions in the last seven days. Data are retrieved as shapefiles from the U.S. Drought Monitor and are updated on a weekly basis. The affected areas are represented by polygons, which are classified according to drought intensity. Using quantitative and objective indicators, as well as local condition and impact reports, the U.S. Drought Monitor defines each drought intensity level as follows:
D0 – Abnormally Dry
D1 – Moderate Drought
D2 – Severe Drought
D3 – Extreme Drought
D4 – Exceptional Drought.
For more information about the data, please see the U.S. Drought Monitor Data Classification web page.
View in Map RoomThis US EPA feature layer is updated hourly and reflects the latest hour of air quality data received from each monitoring site that reports to AirNow. The concentration and AQI values are for Ozone and Particulate Matter (PM) only. Air quality index ranges from 0-5,000 with higher values indicating worse air quality.
View in Map RoomThis layer displays the percentage of weeks in any severity of drought for the years 2021-2023.
View in Map RoomThis layer displays the number of threatened and endangered species in each county. Additional layers are available for the type of species, such as plants, animals, invertebrates, and more!
View in Map Room