18 Feb

Map of the Week: Mapping Environmental Injustice

by Mike Wallace

In January of 2021 the Biden administration issued the Tackling the Climate Crisis at Home and Abroad executive order outlining a new federal environmental justice and climate action agenda. The order arrived alongside the Justice40 initiative, a comprehensive government effort that promises 40% of all federal investments in climate and clean energy to disadvantaged communities. A pillar of the implementation is the development of the Climate and Economic Justice Screening Tool by the White House Council on Environmental Quality, the U.S. Digital Service, and members of the White House Environmental Justice Advisory Council. Released briefly in a beta version in February 2022, the tool coheres a surging amount of environmental and geographic data to locate environmental inequality, health disparity, and climate change risk across the country.

One of the main resources undergirding the next generation of environmental data infrastructure is the Environmental Protection Agency (EPA) EJScreen (Environmental Justice) mapping and screening tool, which went into development in 2010 and became publicly accessible in 2015. Its creation stems from an earlier Executive Order in 1994, #12898, Federal Actions To Address Environmental Justice In Minority Populations and Low-Income Populations, which commanded all federal agencies to “collect, maintain and analyze information assessing and comparing environmental and human health risks borne by populations identified by race, national origin or income.” Only in the last decade through advances in mapping technology has the agency been able to integrate its environmental monitoring and assessments with census, health and transportation data to perform geospatial analysis at scale. EJScreen represents the first nationally consistent tool that can be used by EPA, state and local governments and the public to examine environmental factors along with underlying demographics.

A screenshot of Memphis, Tennessee with the lead paint data set mapped.


The same map of Memphis, TN, now displaying the low income data set.


On a streamlined ArcGIS platform, users can view and overlay color-coded layers containing publicly-available data for 12 different environmental indicators related to proximity or exposure to pollutants and their sources as well as socioeconomic indicators such as income, race, age and/or education. Additional demographic data on different health disparities, food deserts, and broadband access can also be visualized. EJ indexes help summarize and quantify these relationships, highlighting the most susceptible areas by combining spatial datasets from various agencies. Cities or regions can be compared to state or national averages.

A side by side for Philadelphia, Pennsylvania comparing traffic proximity and percentage of the population under the poverty line in different census blocks.


EJScreen also has the ability to create standardized reports summarizing EJ indexes by choosing a county or census block, dropping a pin, drawing an area or a combination. Locations of EPA-regulated facilities, schools, hospitals, tribal lands, parks, public housing, and other sites are all accessible, so taking a superfund site, or an area of wastewater disposal, a user can draw a radius around that site or area and estimate potential impacts on communities or natural areas. The tool also recently added layers related to climate change, including flood risk, droughts, wildfire potential, and sea level rise projections from NOAA. Completely unique or novel maps can also be created by uploading user data as shapefiles or searching thousands of different publicly-available demographic and environmental layers in the geoplatform.

A chart from a report generated from the selection in green above for an area around Colorado Springs, Colorado.


Though EJScreen supplies a wealth of data assets for viewing and analysis, the tool should serve mainly as a starting point for regulators and groups working for environmental justice as well as members of the public seeking more localized information on hazards and risks. One crucial area where EJScreen falls short is the lack of any cumulative impact analysis of pollutants on communities, a function that is supported by California’s CalEnviroScreen, which was an original model for EJScreen. Many other states, such as Colorado, New York, New Jersey, Pennsylvania, Maryland, Washington, North Carolina, and Virginia have similar mapping tools which inform regulatory policy, funding priorities, and law enforcement with regards to historically marginalized and underserved communities dealing with long-term effects of pollution. State level systems are also critical for local regulators and utilities tracking emissions levels, prioritizing power plant retirement, and reaching climate goals.

The Washington state EJ mapping tool.


Those seeking information on particular facilities or locations have many avenues for deeper research, such as ToxicSites, a data visualization application in development to track Superfund sites, or the EPA Enforcement and Compliance History Online (“ECHO”) dashboard which contains facilities’ permit data, inspection/compliance findings, environmental violations and enforcement actions, combining this information with related EJSCREEN demographic features.

ToxicSites map, still under development, but with Superfund sites and ratings displayed.


All of these tools, however, are only as good as the underlying data. The U.S. is still far from having nationally consistent data sets on environmental justice issues, with quality and quantity varying widely across the country. Citizen involvement is necessary to fill in the gaps, and communities must be empowered to identify environmental hazards and document the impacts of pollution and climate change where they live and work. The EPA measures particulate matter from several locations throughout a state, though air pollution levels can vary even between city blocks. Companies like PurpleAir make affordable wifi-enabled air sensors that track air quality and map the results in real-time on their website. Bloomwatch is a crowd source monitoring application to track cyanobacteria blooms through user photos and geocoding. Many municipal governments, universities, and non-profit organizations also compile this data, and train volunteers to collect water, air, and soil samples. These localized databases are incredibly important in directing remediation efforts, conservation resources and pushing regulatory action and oversight.

PurpleAir’s air quality sensor map for a portion of the midwest U.S.


Raleigh, North Carolina volunteer water quality monitoring dashboard.