Clean air actions in China, PM2.5 exposure, and household medical expenditures: A quasi-experimental study

Background Exposure to air pollution, a leading contributor to the global burden of disease, can cause economic losses. Driven by clean air policies, the air quality in China, one of the most polluted countries, has improved rapidly since 2013. This has enabled a unique, quasi-experiment to assess the economic impact of air pollution empirically. Methods and findings Using a series of nation-scale longitudinal surveys in 2011, 2013, and 2015, we first examined the questionnaire-based medical expenditure changes before and after the policy intervention for air pollution. Using a state-of-the-art estimator of the historical concentration of particulate matters with diameter less than 2.5 mu m (particulate matter (PM)(2.5)), we further quantified the association between household medical expenditure and PM2.5 using mixed-effect models of the repeated measurements from 26,511 households in 126 cities. Regression models suggest a robust linear association between reduced PM2.5 and saved medical expenditures, since the association did not vary significantly across models with different covariate adjustments, subregions, or subpopulations. Each 10 mu g/m(3) reduction in PM2.5 was associated with a saving of 251.6 (95% CI: 30.8, 472.3; p-value = 0.026) Yuan in per capita annual medical expenditure. However, due to limitations in data quality (e.g., self-reported expenditures), and imperfect control for unmeasured confounders or impact from concurrent healthcare reform in China, the causality underlying our findings should be further confirmed or refuted. Conclusion In this study, we observed that compared with the PM2.5 reduction in 2013, the PM2.5 reduction in 2017 was associated with a saving of 552 (95% CI: 68, 1036) Yuan / (person x year), or approximately 736 billion Yuan (equivalent to 111 billion US dollar) per year nationally, which is equivalent to approximately 1% of the national gross domestic product of China. Author summary Why was this study done? Exposure to air pollution is a leading contributor to the global burden of disease. Mitigating air pollution can protect public health, so that can save medical expenditures on relevant diseases. The association between air pollution exposure and medical expenditures has been insufficiently studied. China conducted a series of clean air actions since 2013 and rapidly reduced the concentration of PM2.5, a major air pollutant. What did the researchers do and find? We examined medical expenditure changes before and after the policy intervention for air pollution, using a longitudinal nation-scale surveys in 2011, 2013, and 2015. After 2013, the PM2.5 concentration decreased more rapidly, but the medical expenditures increased more slowly. We also associated household medical expenditure to PM2.5 concentration using a mixed-effect models. We found that each 10 mu g/m3 reduction in PM2.5 was associated with a saving of 251.6 Yuan in per capita annual medical expenditure. What do these findings mean? Air pollution was evidenced as a risk factor associated with increased medical expenditure. China's clean air actions could bring a direct health benefit by saving medical expenditure.

Automated summary

The study found a clear linear association between the reduction of PM2.5 concentration due to China's clean air policies and the saving of medical expenditures, with each 10μg/m3 reduction in PM2.5 associated with a saving of 251.6 Yuan in per capita annual medical expenditure. However, due to limitations in data quality, further confirmation of the causal relationship behind the findings is needed.