Abstract
This study investigated the socioeconomic disparities of asthma incidence attributable to ambient particulate matter in aerodynamic diameter ≤2.5 μm (PM(2.5)) exposures among schoolchildren in California, U.S. We found that schoolchildren attending public schools in more vulnerable communities, characterized by higher proportions of people of color, low educational attainment, and poverty, experienced elevated PM(2.5) exposures by 2.07-2.96 μg/m(3). The disproportionate PM(2.5) exposures were likely driven by higher traffic-related emissions and point-source facility emissions in these communities. Using school-specific PM(2.5) concentrations, student enrollment numbers, and model-estimated (not directly observed) baseline age-specific asthma incidence rates, we calculated that the asthma incidence rate attributable to 2016 PM(2.5) exposures was 562 new cases per 100,000 schoolchildren [95% confidence interval (CI) = 311-854]. In absolute terms (i.e., asthma incidence), it was equivalent to 34,537 PM(2.5)-related new asthma cases (95% CI = 19,090-52,493) among all schoolchildren. On average, more vulnerable communities experienced 140 excess new asthma cases per 100,000 schoolchildren (i.e., the difference in average asthma cases per 100,000 schoolchildren between more and less vulnerable groups) across all demographic factors considered. Examining health disparities separately by each demographic factor revealed that race/ethnicity was associated with the largest disparities (209 new cases per 100,000 schoolchildren), followed by educational attainment (128) and poverty (85). Our findings indicate the substantial socioeconomic disparities of asthma incidence attributable to PM(2.5) among schoolchildren in California. Addressing these health disparities could benefit from sustained and long-term emission reduction strategies, such as adopting zero-emission vehicles, which contribute to lower PM(2.5) levels.