Source-specific contributions of particulate matter to asthma-related pediatric emergency department utilization

Few studies have linked specific sources of ambient particulate matter smaller than 2.5 $\mu$m (PM2.5) and asthma. In this study, we estimated the contributions of specific sources to PM2.5 and examined their association with daily asthma hospital utilization in Cincinnati, Ohio, USA. We used Poisson regression models to estimate the daily number of asthma ED visits the day of and one, and two days following separate increases in PM2.5 and its source components, adjusting for temporal trends, holidays, temperature, and humidity. In addition, we used a model-based clustering method to group days with similar source-specific contributions into six distinct clusters. Specifically, elevated PM2.5 concentrations occurring on days characterized by low contributions of coal combustion showed a significantly reduced risk of hospital utilization for asthma (rate ratio: 0.86, 95% CI: [0.77, 0.95]) compared to other clusters. Reducing the contribution of coal combustion to PM2.5 levels could be an effective intervention for reducing asthma-related hospital utilization.