EPA Researchers Release Updates to Environmental Quality Index
Published May 18, 2021
Renowned naturalist and author Rachel Carson wrote, “In nature, nothing exists alone.” Our overall wellbeing depends upon a combination of environmental conditions such as air and water quality and the safety of our built environments.
A look at the broader environmental context can help researchers better understand health outcomes and how they relate to cumulative environmental exposures. EPA researchers created the Environmental Quality Index (EQI) to do just that.
The EQI is a national-level index that helps improve understanding of how multiple environmental conditions affect the 3,143 counties across the U.S.
Originally published in 2014 with data for the period 2000-2005, the EQI team has recently released an update for the 2006-2010 period. The update offers new data sources that were not available for the first edition, as well as additional breakdowns of data layers.
The EQI pulls data from five domains: air, water, land, built, and sociodemographic environments to provide a county-by-county snapshot of overall environmental quality across the entire U.S. This data can then be used to highlight associations between environmental quality and a given health concern.
Interactions between the environment and public health are often complex. For example, people are exposed to various combinations of air pollutants from a range of sources such as vehicle exhaust, wildfire smoke, and industry.
Many health studies examine one pollutant or source at a time. By expanding research beyond singular routes of exposure and pollutants, the EQI helps provide a clearer picture of the relationship between the overall environment and our health.
Dr. Danelle Lobdell, an EPA epidemiologist leading the EQI research, and colleagues recognize that the underlying EQI data has utility beyond just health outcomes. Ecologists, economists, and other researchers can use EQI data to address various questions relating to environmental quality. Similarly, state public health agencies could use the EQI’s county level data to provide targeted support to address health concerns that are tied to environmental quality.
“Visualizing place-based differences that impact health is extremely important in my current position as a geographic information system analyst. The EPA Environmental Quality index provides me with helpful environmental quality data and maps by county that are useful during discussions and projects that involve analyzing the social determinants of health and environmental influences on community health and well-being,” shared Brian Norderud, Montana Department of Public Health & Human Services.
To support this scientific exploration, EPA has made the EQI and its many variables open and accessible to the public through its Technical Report. Additional information about the updates and new variable constructs such as drinking water quality, walkability, and green space, are also included in the report.
“We hope that these and other findings can improve understanding and provide motivation for action around health concerns,” explains Lobdell. “If, for example, a community is seeing increased rates of diabetes, then the results we are finding from the EQI and health analyses may provide insights to explore possible interventions by reducing environmental exposures to in turn reduce adverse health outcomes.”
EPA's EQI team has released several studies linking health concerns such as birth defects and diabetes to environmental quality. The preterm birth study released in 2015, which looked at how different environmental domains might interact with each other to affect preterm birth rates, was the first of its kind. Journal articles relating the EQI to human health research on topics such as birth defects, infant mortality, cancer incidence, life expectancy, and asthma are also available on the EQI website.
Moving forward, the team is exploring the possibility of developing new census-tract level EQIs with local and regional coverage. This work could highlight health disparities tied to environmental conditions at a finer scale—helping prioritize support for those communities that need it most. “We like the versatility of the EQI,” says Lobdell, “and we hope that it can increase our knowledge of cumulative exposures and ultimately help improve public health and wellbeing.”
Learn more about the EQI here, and access datasets and the technical report here.