Map Monday: The Environmental Justice Index

BY BETSY GARDNER • September 12, 2022

Complementing Harvard’s Map of the Month series, Map Monday highlights a data visualization that enhances understanding of or helps resolve a critical civic issue.

According to the US Environmental Protection Agency (EPA), “environmental justice is the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation and enforcement of environmental laws, regulations and policies.” While the fight for environmental justice has been ongoing for decades, there has been renewed attention to environmental injustices in recent years due to extreme heat waves, rising sea levels, and climate migration.

Historically, from the looting and destruction of Indigenous lands to the Love Canal superfund site to “Cancer Alley” in Louisiana, environmental injustices have most affected low-income and Black, Indigenous, and migrant communities. Effects include negative health outcomes from high levels of environmental toxins, increased risk of heat-related illnesses, displacement, economic losses, and early death.

In August 2022 the US Centers for Disease Control and Prevention (CDC) published the Environmental Justice Index (EJI), a digital map tool made with the Agency for Toxic Substances and Disease Registry (ATSDR) and the Department of Health and Human Services. The Index is meant to provide “a single environmental justice score for local communities across the United States,” superseding other, less comprehensive environmental justice maps. The map is freely available, and the CDC’s main goal is providing a national model for community members and public health officials to “identify and map areas most at risk for the health impacts of environmental burden.”

Data is originally from the US Census Bureau, Environmental Protection Agency, Mine Safety and Health Administration, and the CDC and is broken down by census tract. Each tract has a cumulative environmental justice score that ranks the severity of cumulative impacts of environmental hazards on the tract population, defined as “the total harm to human health that occurs from the combination of environmental burden such as pollution and poor environmental conditions, pre-existing health conditions, and social factors.”

The main environmental justice score consists of individual scores for social vulnerability, environmental burden, and health vulnerability. The social vulnerability score includes rates of poverty, high school graduation rates, broadband access, residents with disabilities, and unemployment rates. Environmental burden covers everything from levels of ozone, diesel particulate matter, presence of coal and lead mines, high-volume roads, walkability, and impaired surface water. Health vulnerability includes prevalence of high blood pressure, asthma, cancer, diabetes, and poor mental health.

Map of Flint MI Census Tract 38 (pop. 1,258) with an EJI score of .92 and Ozone score of .75

Flint, Michigan, a city facing an “ongoing drinking water crisis that began in 2014 that disproportionately affects black and low-income residents,” is profiled to help explain how some US communities are facing higher rates of environmental injustice. Flint’s overall EJI ranking ranges from .88 to .96, meaning that the four census tracts that make up Flint are more likely to “experience more severe cumulative impacts from environmental burden” than 88 to 96 percent of other census tracts in the US. Much of this is due to the fact that these communities “rank among the highest in the nation for water pollution and estimated chronic disease burden” as well as a high percentage of residents who identify as a racial/ethnic minorities or experience high rates of poverty and unemployment.

No two tracts have the exact same population, environment, and health conditions, so an advanced data mapping tool like the EJI helps the public and policymakers understand the unique factors that “affect a community’s health and well-being.” Environmental injustices interplay with, and compound, historic injustices that continue to limit the quality and length of life for many Americans. By gathering, analyzing, and visualizing data on more than 30 indicators of well-being, the EJI is helping communities, individuals, and all levels of government prioritize and promote a more equitable and healthy future.

About the Author

Betsy Gardner

Betsy Gardner is the editor of Data-Smart City Solutions and the producer of the Data-Smart City Pod. Prior to joining the Ash Center, Betsy worked in a variety of roles in higher education, focusing on deconstructing racial and gender inequality through research, writing, and facilitation. She also researched government spending and transparency at the Lincoln Institute of Land Policy. Betsy holds a master’s degree in Urban and Regional Policy from Northeastern University, a bachelor’s degree in Art History from Boston University, and a graduate certificate in Digital Storytelling from the Harvard Extension School.