


Historically, before clean air regulations were implemented to control NO x and VOCs, ozone concentrations were high enough to exert acute effects such as eye and nose irritation, respiratory disease emergencies, and lung function impairment. Oxides of nitrogen (NO x) and volatile organic compounds (VOCs) released into the atmosphere can react in the presence of solar irradiation, leading to ozone formation in the troposphere. 5Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China.4State Key Laboratory of Environmental Criteria and Risk Assessment & Environmental Standards Institute, Chinese Research Academy of Environmental Sciences, Beijing, China.3Guangzhou Institute of Respiratory Health, Guangzhou Medical University, Guangzhou, China.

2Global Health Research Center, Duke Kunshan University, Kunshan, China.1Nicholas School of the Environment and Duke Global Health Institute, Duke University, Durham, NC, United States.Junfeng (Jim) Zhang 1,2,3 *, Yongjie Wei 4,5 * and Zhangfu Fang 3
