RESUMO
Both particulate matter with aerodynamics of less than 2.5 (PM2.5) and ozone are the two main air pollutants in China, which seriously endanger human health. To estimate the adverse impacts of PM2.5 and ozone on human health during the implementation of air pollution prevention and control actions in Chengdu, both the generalized additive model and the nonlinear distribution lag model of epidemiology were adopted to explore the exposure-response relationship coefficients ß of daily ozone 8h maximum concentration average (O3-8h), as well as that of PM2.5 on disease deaths in Chengdu from 2014 to 2016. On this basis, the environmental risk model and environmental value assessment model were both adopted to evaluate the health effects and health benefits in Chengdu from 2016 to 2020, respectively, with the assumption that PM2.5 and O3-8h concentration were reduced to specified air pollution control limits (35 µg·m-3 and 70 µg·m-3, respectively). The results showed 1 the annual concentration of PM2.5 presented gradually decreasing trends in Chengdu from 2016 to 2020. Specifically, ρ(PM2.5) from 63 µg·m-3 in 2016 decreased to 40.92 µg·m-3 in 2020. The average annual decline rate was approximately 9.8%. In contrast, the annual concentration of O3-8h from 155 µg·m-3 in 2016 increased to 169 µg·m-3 in 2020, and the increasing rate was approximately 2.4%. 2 Both PM2.5 and O3-8h had lag effects on three types of disease deaths. Under the maximum lag effect, the corresponding exposure-response relationship coefficients ß of PM2.5were 0.0003600, 0.0005001, and 0.0009237 for all-cause, cardiovascular, and respiratory premature deaths, respectively, whereas the corresponding ß of O3-8h were 0.0003103, 0.0006726, and 0.0007002, respectively. 3 If ρ(PM2.5) was reduced to the national secondary standard limit (35 µg·m-3), the corresponding number of health beneficiaries and economic benefits declined yearly. Specifically, the health beneficiary number of all-cause, cardiovascular, and respiratory disease deaths were reduced from 1128, 416, and 328 in 2016 to 229, 96, and 54 in 2020, respectively. There were a total number of 3314 avoidable premature deaths for all-cause diseases during the five years, resulting in a total health economic benefit of 7.66 billion yuan. 4 If we assume that ρ(O3-8h) was reduced to the concentration limit specified by the World Health Organization (70 µg·m-3), the corresponding number of health beneficiaries and economic benefits were increasing yearly. Specifically, the health beneficiaries' numbers of all-cause, cardiovascular, and respiratory disease deaths rose from 1919, 779, and 606 in 2016 to 2429, 1157, and 635 in 2020, respectively. The annual average growth rates of avoidable all-cause and cardiovascular mortality were 6.85% and 10.72%, respectively, which was higher than the annual average rise rate of ρ(O3-8h). There were 10790 total avoidable deaths from all-cause diseases during the five years, resulting in a total health economic benefit of 26.62 billion yuan. These findings indicate that PM2.5 pollution in Chengdu had been well controlled, whereas O3 pollution had become more severe and had become another key air pollutant threatening human health. Therefore, the synchronous control of PM2.5 and ozone should be implemented in the future.
