Satellite Observations of Atmospheric Ammonia Inequalities Associated with Industrialized Swine Facilities in Eastern North Carolina

Industrialized swine facilities adversely affect the health and well-being of Eastern North Carolina residents in the U.S. and are an issue of environmental racism. Concentrated animal feeding operations (CAFOs) emit various harmful and noxious air pollutants, including ammonia (NH₃). There are limited measurements of CAFO-related air quality, contributing to disputes around its severity. We use NH₃ vertical column densities from the space-based Infrared Atmospheric Sounding Interferometer (IASI) to report systematic, distributive inequalities in NH₃ column enhancements (ΔNH₃ columns), equal to NH₃ columns less an observationally determined tropospheric background. Population-weighted block group-scale ΔNH₃ columns are higher by 27 ± 3% for Black and African Americans, 35 ± 3% for Hispanics and Latinos, and 49 ± 3% for American Indians compared to non-Hispanic/Latino whites in Eastern North Carolina (April-August 2016-2021). Surface winds and air temperature influence block group-scale NH₃ distributions, with higher absolute NH₃ inequalities for all groups on calm days and for Black and African Americans and Hispanics and Latinos on hot days, consistent with effects from NH₃ volatization downfield of facilities from, e.g., manure-covered fields, particles, and other surfaces. ΔNH₃ columns correspond spatially with permitted swine facilities, with residents living multiple kilometers from swine CAFOs chronically exposed to elevated NH₃. Trends in NH₃ columns over 2008-2023 are driven by regional-scale atmospheric processes rather than localized NH₃ changes in CAFO emissions. Results are discussed in local decision-making contexts that have broad relevance for air quality issues without protective federal regulatory standards.