Race disparities in total PM2.5 and wildfire-specific PM2.5 exposure among disaggregated Asian American, Native Hawaiian, and Pacific Islander groups in California

Introduction Environmental health disparities in the United States (US) are evident in PM 2.5 exposure, but few studies have documented wildfire-specific PM 2.5 disparities. Furthermore, aggregating broad racial groups may hide disparities for Asian American (AA) and Native Hawaiian or Pacific Islander (NHPI) groups. We investigated racial disparities in total and wildfire-specific PM 2.5 exposure in California and determined whether disaggregating AA and NHPI groups revealed previously hidden disparities. Methods We conducted a cross-sectional descriptive analysis using data from the US Environmental Protection Agency’s Air Quality System data (2008-2012) to assess average total PM 2.5 levels in census tracts, including wildfire-specific PM 2.5 . The 2010 U.S. Census provided census tract level counts for American Indian/Alaska Native, AA, Black, NHPI, White, and 19 disaggregated AA and 10 disaggregated NHPI groups. We calculated population-weighted average exposure to total PM 2.5 and wildfire-specific PM 2.5 for all race groups across California state. Results Results showed differences in the distribution of total PM 2.5 compared to wildfire-specific PM 2.5 in the state. Disaggregated data revealed disparities, including high exposure to total PM 2.5 among several disaggregated AA and NHPI groups and Black populations. Hmong populations experienced the highest average exposure to total PM 2.5 and wildfire-specific PM 2.5 compared to all other race groups. The highest average wildfire-specific PM 2.5 exposure was observed among Hmong, Fijian, Laotian, Bhutanese, Marshallese, and other Micronesian populations. Conclusion Race disparities exist for total and wildfire-specific PM 2.5 . Disaggregating AA and NHPI groups reveals disparities among certain populations. This study informs future community-based efforts to assess and address health risks associated with exposure to PM 2.5 .