Seeing red

April 15, 2022

This article appeared in Berkeley Engineer magazine, Spring 2022

Redlining — a federally-backed, discriminatory mortgage appraisal practice dating to the 1930s — was a widespread policy that deemed certain areas as hazardous and excessively risky for investment if they included high concentrations of Black, Asian, immigrant or working-class residents. This designation blocked access to favorable lending and other services.

A new study has now found a strong association between present-day air pollution levels and historical patterns of redlining. Looking at year-2010 levels of two regulated air pollutants — nitrogen dioxide (NO₂) and fine particulate matter (PM_2.5) — in 202 U.S. cities, the study’s researchers found that areas that were redlined in the 1930s consistently had higher levels of pollution today than those areas that received favorable treatment. Strikingly, air pollution disparities associated with historical redlining status in these cities were even larger than those associated with race and ethnicity.

The paper also found racial disparities within redlined neighborhoods, suggesting that housing discrimination is one of many factors propelling environmental racism. In other words, white people who happen to live in redlined neighborhoods still have lower air pollution exposure than people of color in that same community. That trend held across non-redlined and redlined neighborhoods alike.

“Redlining is a good predictor of air pollution disparities, but it’s only one of the things that drive the racial and ethnic disparities in air pollution,” said senior author Joshua Apte, assistant professor of civil and environmental engineering and of public health. “It’s not the only source of disparity that we ought to be concerned about.”

Haley Lane, Ph.D. student in civil and environmental engineering, was the study’s first author; Rachel Morello-Frosch, professor of environmental science, policy and management, and Julian Marshall of the University of Washington were co-authors.

Learn more: Study shows more air pollution in areas of historical redlining (Berkeley Public Health)