Particulate Matter Pollution in an Agricultural Setting: A Community-Engaged Research Study

California's San Joaquin Valley experiences some of the worst particulate matter (PM) air pollution in the U.S., but PM_2.5 and PM₁₀ exposures in agricultural communities are understudied. We collaborated with rural residents living adjacent to large-scale agricultural production and processing activities to assess 24-h-average personal and indoor PM_2.5 and PM₁₀ concentrations during different seasons. We visited 35 participants from 18 households during December 2023, May 2024, and the September 2024 harvest season to collect PM samples and survey data. Mixed effects linear regression models (with random effects for participant or household) assessed associations between natural log-transformed PM concentrations and regional ambient PM, harvest season, as well as participant/household characteristics. Participants were mostly female (69%) and Hispanic/Latino(a) (100%). Median household distance to processing facility silos was 633 m. Median personal exposures to PM_2.5 and PM₁₀ were 11.1 and 45.5 μg m^-3. Median indoor PM_2.5 and PM₁₀ levels were 12.9 and 24.3 μg m^-3. Overall, 29% of personal and indoor PM_2.5 samples and 33% of personal and indoor PM₁₀ samples exceeded WHO 24-h air quality guidelines (15 μg m^-3 PM_2.5, 45 μg m^-3 PM₁₀). The factors most strongly associated with personal and indoor PM were household members working in agriculture and regional ambient PM measures.