Abstract View
Historic Redlining and Modern Disparities in U.S. Urban Air Pollution Exposure
HALEY LANE, Julian Marshall, Rachel Morello-Frosch, Joshua S. Apte, University of California, Berkeley
Abstract Number: 670
Working Group: Translating Aerosol Research for Societal Impact: Science Communication and Public Outreach
Abstract
Racial-ethnic minorities in the US are systematically exposed to higher levels of air pollution. We explore here how redlining, a racist mortgage appraisal practice started in the 1930s, affects present-day intra-urban air pollution disparities in 202 US cities. In each city, we integrated two data sources: 1) detailed Security Maps drawn by the Home Owners' Loan Corporation (HOLC) that assigned neighborhood investment risk grades of A (‘best’, green), B (blue), C (yellow), and D (‘hazardous’, red, i.e., redlined); and 2) year-2010 estimates of NO2 and PM2.5 concentrations by US Census block derived from a national integrated empirical geographic air pollution model. Three findings are especially noteworthy. (1) We find large present-day intra-urban disparities in air pollution exposure which are consistently associated with historical redlining. Specifically, residents in historically redlined (grade “D”) neighborhoods experience air pollution levels that are 7% [NO2] and 1% [PM2.5] higher than city-wide mean concentrations, on average. Meanwhile, air pollution levels for residents in grade A neighborhoods are 15% [NO2] and 3% [PM2.5] lower than city-wide means. The contrast between NO2 and PM2.5 likely reflects the difference between a largely traffic-related, nearly-primary pollutant [NO2] versus a secondary, regional pollutant [PM2.5] which is attributable to multiple sources. (2) Within individual cities, average NO2 exposure disparities associated with redlining were double those associated with race and ethnicity. (3) Within each separate historical HOLC classification code, racial- and ethnic exposure disparities persist. Our findings illustrate how the legacy of racially exclusive housing policy and urban planning continues to shape systemic environmental exposure disparities in the US.