摘要
The adverse impacts of air pollution on human health have already been a major environmental issue globally,and the challenges are even more severe in China.The World Health Organization(WHO)estimates that 4.2 million deaths annually can be attributed to outdoor air pollution in 2016(1).For example,ambient fine particulate matter(PM2.5)has been ranked as the fourth leading risk factor for disease in China(2).Atmospheric ozone(O3)pollution has demonstrated an increasing trend year by year,and the problem of regional compound pollution has become prominent.
