Over the past two decades, emissions from cars and trucks have become a significant source of air pollution in China. In the late 1990s, China began to implement policies to mitigate traffic pollution but the outcomes of those policies, especially on air quality and public health, have never been systematically evaluated.
Now, several researchers from Harvard—including Professor John Evans and doctoral student Ernani Choma of the Harvard T.H. Chan School of Public Health—joined a team led by Haikun Wang, Professor of Environmental Sciences at Nanjing University, in a collaborative study of the topic begun while Wang was a visiting scholar in the Harvard-China Project at SEAS.
Analyzing those policies using a framework that combines emission scenarios, air quality modeling, and population health risk assessment, the team found that pollution control policies in China reduced vehicle emissions by one-half to two-thirds compared to what otherwise would have occurred, and led to roughly 510,000 fewer deaths attributable to fine particle and ozone exposures in 2015.
The research was published in the Proceedings of the National Academy of Sciences.
“Our research showed that while the vehicle population and traffic congestion have grown quickly in China, strict control measures implemented by the government have limited the resulting emissions and brought huge benefits in avoided health impacts of air pollution across the country, especially in cities,” said Chris Nielsen, Executive Director of the Harvard-China Project and a co-author of the paper.
RESEARCH CITED: Haikun Wang, Xiaojing He, Xinyu Liang, Ernani F. Choma, Yifan Liu, Li Shan, Haotian Zheng, Shaojun Zhang, Chris P. Nielsen, Shuxiao Wang, Ye Wu, and John S. Evans. 2020. “Health benefits of on-road transportation pollution control programs in China.” Proceedings of the National Academy of Sciences, Sept 2020, 201921271.
By: Leah Burrows, Harvard John A. Paulson School of Engineering and Applied Sciences