2 Sep 2025

EJ Screen Lead Paint Exposure

The lead paint indicator is the percentage of occupied housing units built before 1960, calculated from
the U.S. Census Bureau’s ACS 5-year summary estimates on age of housing stock. EJScreen uses age of
housing stock as a surrogate for potential lead exposure as regulations banning lead-based residential
paint in 1978 led to the reduction and finally an end to the use of such paint in housing. The percentage
of older housing units is a proxy for potential exposure to lead paint and lead-containing dust that
accumulates indoors, in homes, or in other buildings where lead paint was used. EJScreen uses housing
units built before 1960.

2 Sep 2025

EJ Screen Air Toxic Respiratory Risk

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.

2 Sep 2025

EJ Screen Superfund Proximity

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.

2 Sep 2025

EJ Screen Hazardous Waste Proximity

The hazardous waste proximity indicator is reflective of the total count of hazardous waste facilities 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. Hazardous waste facilities are defined as
Resource Conservation and Recovery Act (RCRA) handlers that are either operating TSDFs from RCRA or
reporting LQGs from the 2019 BR.

2 Sep 2025

EJ Screen Ozone

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.