Skyscrapers in Downtown Los Angeles as photographed from an airplane during the research campaign. Photo courtesy of Eva Pfannerstill.
Disadvantaged communities in Los Angeles experience significantly higher concentrations and emissions of hazardous air pollutants (HAPs), a class of substances that have been linked to adverse health effects like increased cancer risk, reproductive complications, and developmental issues, according to a recent study led by researchers in the Department of Environmental Science, Policy, and Management (ESPM).
The findings, which were published last month in Environmental Science & Technology, are based on an analysis of the first-ever direct aircraft-based observations of HAP emissions and concentration collected in Los Angeles. The data suggests that low-income residents and communities of color in Los Angeles, which routinely ranks as one of the most polluted regions in the United States, are still disproportionately burdened by the legacy of discriminatory practices like redlining and racial segregation.
Jennifer Ofodile, PhD ’25 ESPM, and postdoctoral researcher Eva Pfannerstill are co-first authors of the paper, with the research study led by Allen Goldstein, a UC Berkeley professor in the Departments of ESPM and Civil and Environmental Engineering.
To conduct their analysis, the researchers mounted advanced mass spectrometry equipment in a plane and collected measurements while flying over Los Angeles. While widespread data is readily available for air pollutants like particulate matter, information about HAP emissions is scarce. The authors combined data they gathered with information about race, ethnicity, and household income for more than 1,000 census tracts to determine which communities experienced the highest distribution and concentration of HAP emissions.
“This research is both the first-ever airborne HAP flux measurements in Los Angeles and the most spatially detailed measurements of HAP emissions and concentrations ever reported for any megacity,” said Ofodile.
The findings showed that disadvantaged communities experienced significantly higher concentrations and emissions of HAPs related to vehicle traffic than non-disadvantaged communities. The researchers also found that census tracts with large Hispanic populations are disproportionately exposed to HAPs related to the use of solvents and industrial activity, and that low-income Hispanic populations experience HAP emissions that are 107% greater than emissions in high-income white areas.
Additional UC Berkeley co-authors include Cesunica Ivey, an assistant professor of Civil and Environmental Engineering; and visiting scholar Caleb Arata, PhD ’20 Chemistry.
Ofodile is now a Principal Air Quality Specialist at the Bay Area Air District in San Francisco. Pfannerstill is now Helmholtz Investigator Group leader at Forschungszentrum Jülich, Germany, and a Junior Professor at University of Cologne.
Read the full study in Environmental Science & Technology.