Frequent Questions about EJScreen
- What is EJScreen?
- Why did EPA create an EJ screening tool?
- What is an EJ or supplemental index?
- How does EPA use EJScreen?
- Does EPA use any filters, benchmarks, or thresholds, as a part of interpreting indicators or indexes found in reports, as part of the screening process?
- What were the criteria for including these environmental indicators?
- Why are some datasets older than others?
- Why do you only consider proximity to some facilities and not emissions or risk from those facilities?
- Why do only certain types of facilities or regulated sites have a proximity measure?
- Why are air quality datasets in EJScreen presented at the census tract level and not at higher resolution?
- Can I add my own data into EJScreen? Can I add my own boundaries / locations?
- How do I cite EJScreen?
- Are people living in areas with a high lead indicator, indicating a higher percentage of pre–1960s housing than other block groups, always at high risk of lead hazards?
- How does the wastewater discharge indicator work and why does my location report high?
- How is the EJScreen Hazardous Waste Proximity environmental indicator different from the Hazardous Waste Proximity indicator that was used in EJScreen versions prior to 2018?
- What amount of sea level rise should I look at in EJScreen and what does it represent?
- What's the difference between AirToxScreen and EJScreen?
- What data is available for the U.S. Territories?
- What are threshold maps?
- What are the supplemental indexes?
- Why did EPA create supplemental indexes?
- Where to find more information related to the Toxic Releases to Air indicator?
What is EJScreen?
EJScreen is an environmental justice screening and mapping tool that utilizes standard and nationally-consistent data to highlight places that may have higher environmental burdens and vulnerable populations. The tool offers a variety of powerful data and mapping capabilities that enable users to access environmental and demographic information, at high geographic resolution, across the entire country; displayed in color-coded maps and standard data reports. These maps and reports show how a selected location compares to the rest of the nation, EPA region or state. The tool also combines environmental and demographic indicators to create EJ and supplemental indexes.
Why did EPA create an EJ screening tool?
EJScreen helps EPA meet the intent of Executive Order 12898, "Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations," to focus federal attention on the environmental and human health conditions of minority and low-income populations with the goal of achieving environmental protection for all communities. An important first step to ensuring environmental justice for all people in this country is to identify the potential areas where people are most vulnerable or likely to be exposed to different types of pollution. For this reason, EPA developed EJScreen to help aid in efforts to ensure programs, policies and resources are appropriately inclusive and consider the needs of communities most burdened by pollution.
What is an EJ or supplemental index?
The EJ and supplemental indexes are methods of combining demographic information with a single environmental indicator – such as proximity to traffic – that can help identify communities that may have a high combination of environmental burdens and vulnerable populations.
How does EPA use EJScreen?
EPA uses EJScreen to identify areas that may have higher environmental burdens and vulnerable populations as the Agency develops programs, policies and activities that may affect communities. A few examples of what EJScreen supports across the Agency include:
- Informing outreach and engagement practices;
- As an initial screen for voluntary programs, enhanced outreach in permitting, and prioritizing enforcement work;
- Developing retrospective reports of EPA work; and
- Enhancing place-based activities.
EJScreen is not used by EPA staff for any of the following:
- As a means to identify or label an area as an “EJ community;”
- To quantify specific risk values for a selected area; or
- As the sole basis for EPA decision-making or making a determination regarding the existence or absence of EJ concerns.
Does EPA use any filters, benchmarks, or thresholds, as a part of interpreting indicators or indexes found in reports, as part of the screening process?
In past screening experience, EPA has found it helpful to establish a suggested Agency starting point for the purpose of identifying geographic areas that may warrant further consideration, analysis or outreach. The use of an initial filter promotes consistency and provides a pragmatic first step for EPA programs and regions when interpreting screening results. For early applications of EJScreen, EPA identified the 80th percentile filter as that initial starting point. As EPA gains further experience and insight into the performance of the tool and its applicability for different uses, program offices and regions may opt to designate starting points that are more inclusive or specifically tailored to meet programmatic needs more effectively. Read the EJScreen Technical Documentation for more information on this topic.
What were the criteria for including these environmental indicators?
The environmental indicators included are those for which there are national, publically-available data at a sufficient geographic resolution. Other types of information, either not available at the appropriate spatial resolution (e.g., radon), or not available nationwide (e.g., local health data) could be overlaid on top of EJScreen maps by adding the relevant geospatial data layers.
Why are some datasets older than others?
The process for collecting data from across the country, modelling it, and inserting it into EJScreen varies across the different indicators. Some datasets, like the Air Toxics data, are also updated less frequently than others, resulting in varying years of vintages. EPA is committed to updating EJScreen annually as new datasets become available.
Why do you only consider proximity to some facilities and not emissions or risk from those facilities?
EJScreen does include some risk estimates, for example, the Air Toxics cancer risk, but these are aggregated risks from many sources that do not represent risk estimates for individual facilities. EJScreen also includes some environmental indicators highlighting potential exposure (e.g., ambient concentrations of PM2.5 and ozone (O3)). EJScreen uses distance weighted proximity as a proxy for the potential impact of specific types of facilities. Site-specific risk estimates would require much more data and analysis, beyond what could be reasonably be included in a national screening tool.
Why do only certain types of facilities or regulated sites have a proximity measure?
The intent of the proximity measures is to include facilities that are important and not covered in another environmental indicator.
- Risk Management Plan (RMP) sites are included because of the potential severe effects of an accidental release of a highly hazardous substance into the air.
- Treatment Storage and Disposal Facilities are included because they were the focus of much early EJ research and community action.
- EPA National Priorities List (NPL)/ Superfund sites are included because of the concerns associated with being in close proximity to an NPL site.
Why are some air quality datasets in EJScreen presented at the census tract level and not at higher resolution?
Air modeling results illustrate geographic patterns of exposure and potential health risk from air toxics. These results can then inform efforts to prioritize pollutants and geographic areas of interest or to suggest more refined data collection such as monitoring. Ozone and PM air quality concentrations are derived from both ambient monitoring data and from regional-scale modeling.
Risk information and PM and ozone concentrations are presented at the census tract level rather than the county level so that patterns of relatively lower and higher levels of risk and concentration data within a county can be seen, rather than one result for an entire county. The predicted risks and air quality concentrations are not suited to pinpointing either specific concentration levels or exact locations where higher risks or concentrations may exist but rather to illustrate broader-scale geographic patterns of air quality. The census block results presented by EJScreen site are actually census tract values distributed homogeneously across all census blocks within a census tract.
Can I add my own data into EJScreen, such as other boundaries or locations?
There are a variety of ways to add your own data into EJScreen. Data can be added as a shapefile, mapservice or through EPA’s GeoPlatform. Please note, EJScreen will only display the added layer; it will not integrate the added information into the calculation of the indexes. For example, if you add a data layer that maps children’s blood lead levels, EJScreen will show this layer in addition to other EJScreen data. However, it will not provide quantitative information about the layer you added.
How do I cite EJScreen?
If you use information from EJScreen, please cite the information as follows: United States Environmental Protection Agency. 20xx version [cite the year of the version used]. EJScreen. Retrieved: [Enter Month, Day, Year, from url (the url cited should be the exact url you accessed) or www.epa.gov/ejscreen for a general citation.] To cite specific data content, please also use the citation contained within the relevant metadata.
To cite specific EJScreen publications (e.g., journal articles), please use the appropriate citation. For the EJScreen Technical Documentation, please cite as follows (using the relevant year to specify which version of documentation is being cited):
U.S. Environmental Protection Agency (EPA), 2017[or use the latest year of documentation available]. EJScreen Technical Documentation.
Are people living in areas with a high lead indicator, indicating a higher percentage of pre–1960s housing than other block groups, always at high risk of lead hazards?
No. The lead paint indicator is based solely on the age of the housing stock in a selected block group and highlights homes built prior to 1960 because lead paint was commonplace during that era. The indicator does not, however, take into account any remediation of lead paint which has occurred through government programs to reduce lead in homes, general home renovations or other factors. For this reason, many areas that include government-assisted housing rank high in the EJScreen lead paint indicator when in fact, housing that is government-assisted is, on average, significantly more lead safe than unassisted housing from that era.
Similarly historic neighborhoods often appear in the top percentile of the lead paint indicator despite the fact that these historic homes may be lead safe as a result of remediation. This example highlights how EJScreen should be used for screening purposes only and why it is critical to obtain additional information before identifying a concern.
How does the wastewater discharge indicator work and why does my location report high?
To understand why a given location’s wastewater discharge indicator is high, it is necessary to understand how the indicator functions. The wastewater discharge indicator takes the pollutant discharge information reported from facilities to EPA and assigns it to the streams and rivers which receive those discharges. This complex mapping process includes toxicity-weighted results, or giving more weight to the pollutants which have greater impact on human health. It also must account for dilution as these pollutants move downstream. Following this, the indicator ranks Census block groups based on the proximity to these stream segments and the toxicity-weighted pollutant discharge.
Because EJScreen is a screening tool, the wastewater discharge indicator should be validated with other information, including local and state data. One source of data which may be helpful as a first step is looking at the reported pollutant data underlying this indicator. This data is public and can be found in the EPA’s DMR Pollutant Loading Tool at https://cfpub.epa.gov/dmr/. A more detailed explanation of the wastewater discharge indicator can be found in the EJScreen Technical Documentation.
How is the EJScreen Hazardous Waste Proximity environmental indicator different from the Hazardous Waste
Proximity indicator that was used in EJScreen versions prior to 2018?
The previous indicator used the locations of Hazardous Waste Treatment, Storage, and Disposal Facilities (TSDF) as a proxy for potential exposure to hazardous waste in communities. These are facilities treat that receive hazardous wastes for treatment, storage or disposal. The new Hazardous Waste Proximity indicator includes the TSDF facilities as well as waste generating facilities that report in the Biennial Hazardous Waste Report (BR). The BR requires large quantity generators to submit a report regarding the nature, quantities and disposition of hazardous waste generated at their facility. This data set focuses on industrial generators that discard chemicals and by products generated through manufacturing processes. For more information, see the Biennial Hazardous Waste Report.
What amount of sea level rise should I look at in EJScreen and what does it represent?
Over the next 30 years, scientists expect most of the US coastline will see an increase of one to three feet in mean sea level (see the CO-OPS Technical Report (pdf) (75 pp, 6.7 MB, About PDF) for more information). EJScreen enables you to explore the risks an increase of up to six feet in mean sea level poses to coastal areas. The map depicts the land that could be permanently flooded if action isn’t taken to protect the coastline.
As one assesses the impacts sea level rise may have on coastal areas, it is important to remember the risks aren’t limited to increases in average sea level. Storm surges, such as those that occur during hurricanes or winter storms, can produce water levels much higher than normal high tide, resulting in more severe and extensive coastal and inland flooding. The impact of these and related types of extreme events are not captured by the displayed maps. For more in depth information on sea level rise, please visit the National Oceanic and Atmospheric Administration’s Sea Level Rise Viewer website.
What's the difference between AirToxScreen and EJScreen?
AirToxScreen is a national screening assessment that estimates cancer and noncancer risks from breathing air toxics. AirToxScreen is intended to help users prioritize pollutants, types of emission sources, and places of interest for further study. EJScreen is an environmental justice mapping and screening tool that combines several environmental and demographic indicators to produce indices. Air toxics is one of many environmental indicators included in EJScreen.
EJScreen includes AirToxScreen’s cancer risk data as one of its datasets. However, AirToxScreen and EJScreen display these data somewhat differently. AirToxScreen focuses on providing air toxic risk information only. EJScreen merges the air toxics risk data with demographic data to create indices.
AirToxScreen provides detailed emissions data, source contributions to risk, hazard index results, monitoring data, and other details about air toxics. EJScreen's focus is on the indices and as such it does not display these data.
What data is available for the US territories?
EJScreen 2.1 features the addition of select environmental indicators (and associated indexes) as well as socioeconomic data for the US Virgin Islands, Guam, American Samoa, and Northern Mariana Islands. This additional data provides for the consideration of EJ in all places within the country.
What are threshold maps?
The threshold map widget allows EJScreen users to look across all twelve indexes at once, providing a cumulative outlook on vulnerable populations facing higher pollution burdens. Users select a percentile range, for example the 80th to 100th percentile, and the tool then maps places where one or more of the indexes is within that range. The tool also allows users to select the number of indexes within the user-defined range or to select specific indicators of interest. Threshold maps are available for both the EJ indexes and the new supplemental indexes and are available for comparison at the national and state level.
What are the supplemental indexes?
The supplemental indexes are combinations of the twelve single environmental indicators with five socioeconomic factors. The supplemental indexes use the same EJScreen methodology and calculation as the EJ indexes but are based on a new five-factor supplemental demographic index, rather than the two-factor demographic index. The five demographic indicators that are considered in the supplemental demographic index are: percent low-income, percent linguistically isolated, percent less than high school education, percent unemployed, and low life expectancy.
Why did EPA create supplemental indexes in EJScreen?
The supplemental indexes offer a different perspective on community-level vulnerability across the country. The supplemental indexes also provide additional functionality for use in decision-making consideration, such as the allocation of government resources when awarding grants. For questions on the appropriate use of the EJ and supplemental indexes, please contact your servicing legal office.
Where to find more information related to the Toxic Releases to Air indicator?
Source data for the Toxics Releases to Air indicator are derived from data used in and results from EPA’s Risk-Screening Environmental Indicators (RSEI) model. RSEI model results offer a screening-level and geographic perspective for relative comparisons of potential health impacts resulting from certain waste management activities of chemicals included on the Toxics Release Inventory list, established and maintained under section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA). RSEI primarily relies on data submitted by regulated facilities to EPA’s Toxics Release Inventory (TRI) Program, which compiles and makes available the information reported by facilities that are subject to the TRI reporting requirements. More details and information on the RSEI Geographic Microdata results for air, as well as other geographic-based RSEI modeled results can be found and further analyzed by visiting the RSEI Geographic Microdata website.