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Apportionment of Metals and Particulate Matter at an Environmental Justice School in Maywood, California
STEVEN G. BROWN, Olivia Ryder, Jennifer DeWinter, Hilary Hafner, Jenny Lentz, Joe Lyou, Felipe Aguirre, Sonoma Technology, Inc
Abstract Number: 174
Working Group: Urban Aerosols
Abstract
The community of Maywood in Los Angeles County, California, is surrounded by freeways with heavy truck traffic, a major railyard, and industrial facilities. Maywood is in the highest (1st) percentile of the environmental justice index for air pollution. During May-July 2019, we collected measurements at Heliotrope Elementary School in Maywood to determine sources and concentrations of metals, chromium-6, and diesel particulate matter (DPM), as well as to estimate associated health risks to the community. We collected hourly speciated metals via an Xact 625i, black carbon via an AE33 Aethalometer, PM2.5 via a T640 instrument, plus chromium-6 and meteorological measurements. Chromium-6 concentrations were, on average, 0.065 ng/m3, typical of urban Los Angeles levels, and associated with cancer risk of 2-in-a-million. Arsenic was the metal with the highest cancer risk, of 3 in-a-million, while DPM had a cancer risk more than 10 times higher than either arsenic or chromium-6. Using a combination of bivariate polar plots, source apportionment with positive matrix factorization (PMF), and other techniques, we found that arsenic was predominantly from reentrained dust that had been contaminated over previous decades from local arsenic emissions. Local sources were the main contributors to chromium and nickel concentrations. DPM concentrations were from a combination of emissions from the I-710 freeway and local arterial roads. These findings are being used by the community to develop an emission mitigation plan as part of the overall California AB 617 community air pollution reduction program. In addition to the scientific findings, we will present how results were shared and communicated with the community and how they are using the results to advance change.