The Causal Relationship Between Long-Term Exposure to Major PM2.5 Constituents and the Rate of Emergency Department Visits: A Difference-in-Differences Study

作者：Peizhen Zhao, Chunjuan Xie, Shenghao Wang, Shao Lin, Guang‐Hui Dong, Jiashun Li, S. F. Yu, Ting Zhang, Xiaozhou Yu, Xian Lin, Shujuan Li, Xiaoru Wu, Ji‐Yuan Zhou, Wangjian Zhang · 发表于：Toxics · 年份：2025 · DOI：10.3390/toxics13110973 · 被引用次数：1 · 研究领域：Air Quality and Health Impacts、Climate Change and Health Impacts、Atmospheric chemistry and aerosols

Fine particulate matter (PM2.5) is a well-established health hazard, yet population-level causal evidence on the long-term effects of its chemical constituents and their interactions with environmental and socioeconomic factors remains scarce. This study leveraged quasi-experimental variation in PM2.5 exposure across Guangdong province, China, during 2007–2018 to evaluate its causal impact on emergency department (ED) visits. We applied a Difference-in-Differences (DID) causal inference framework to obtain counterfactual estimates of long-term exposure effects and complemented this with generalized Weighted Quantile Sum (gWQS) regression to treat PM2.5 as a complex mixture, quantify joint effects, and identify toxic components. The results showed that each interquartile increase in long-term PM2.5 exposure was associated with a 10.2% rise in ED visits, with nitrate (weight = 0.299) and sulfate (0.294) contributing the most strongly, while organic matter exerted greater effects in less-developed regions. Temperature variation further modified these effects, with a 1 °C increase in average summer temperature associated with a 3.3% increase and a decrease in winter temperature linked to a 0.54% increase in constituent-related ED visits. Socioeconomic stratification revealed heterogeneous toxicity profiles across regions. These findings provide robust causal evidence on constituent-specific risks of PM2.5, highlight the utility of integrating causal and mixture methods for comple...