Landscape fire PM and hospital admissions for cause-specific cardiovascular disease in urban China.

There is a growing interest in the health impacts of PM originating from landscape fires. We conducted a time-series study to investigate the association between daily exposure to landscape fire PM and hospital admissions for cardiovascular events in 184 major Chinese cities. We developed a machine learning model combining outputs from chemical transport models, meteorological information and observed air pollution data to determine daily concentrations of landscape fire PM. Furthermore, we fitted quasi-Poisson regression to evaluate the link between landscape fire PM concentrations and cardiovascular hospitalizations in each city, and conducted random-effects meta-analysis to pool the city-specific estimates. Here we show that, on a national scale, a rise of 1-μg/m in landscape fire PM concentrations is positively related to a same-day 0.16% (95% confidence interval: 0.01%-0.32%) increase in hospital admissions for cardiovascular disease, 0.28% (0.12%-0.44%) for ischemic heart disease, and 0.25% (0.02%-0.47%) for ischemic stroke. The associations remain significant even after adjusting for other sources of PM. Our findings indicate that transient elevation in landscape fire PM levels may increase risk of cardiovascular diseases.