Risks of source and species-specific air pollution for COVID-19 incidence and mortality in Los Angeles

Growing evidence from ecological studies suggests that chronic exposure to standard air pollutants (PM2.5, NO2, and ozone) exacerbates risks of COVID-19 incidence and mortality. This study assessed the associations between an expanded list of air pollutants and COVID-19 incidence and mortality in Los Angeles. Annual mean exposure to air pollutants in 2019  including PM0.1 mass, PM2.5 mass, PM2.5 elemental carbon (EC), PM2.5 tracer from mobile sources, NO2, and ozone  were estimated at the ZIP code level in residential areas throughout Los Angeles. Negative binomial models and a spatial model were used to explore associations between health outcomes and exposures in single pollutant and multi-pollutant models. Exposure to PM0.1 mass, ozone, NO2, and PM2.5 EC were identified as risk factors for COVID-19 incidence and mortality. The results also suggest that PM2.5 and NO2 together may have synergistic effects on harmful COVID-19 outcomes. The study provides localized insights into the spatial and temporal associations between species-specific air pollutants and COVID-19 outcomes, highlighting the potential for policy recommendations to mitigate specific aspects of air pollution to protect public health.