The effects of PM concentrations on traffic violations and accident severity in Guangdong China.

How does air pollution affect road safety? This study examines the impact of local PM concentrations on traffic violations and accident severity in Guangdong Province, China, from 2006 to 2014. Using instrumental variable methods to address endogeneity, we find a significant relationship between PM concentrations and the occurrence of high-penalty traffic violations and severe accidents. Robustness checks confirm these results hold when using alternative pollutants (PM, SO, and SO). To account for the bias caused by nonlinear relationships between air pollution and weather, we employ a random forest model to isolate the weather-independent component of PM concentrations. Further analysis reveals significant heterogeneity in these effects across driver characteristics and geographic areas. This paper also explores potential visual and psychological mechanisms through which PM influences traffic safety. Our findings offer valuable policy implications for environmental and traffic management strategies.