Improved air quality can be a major bonus of climate mitigation policies aimed at reducing greenhouse gas emissions. By cutting air pollution levels in the country where emissions are produced, such policies can avoid significant numbers of premature deaths. But other nations downwind from the host country may also benefit.
A new MIT study in the journal Environmental Research Letters shows that if the world’s top emitter of greenhouse gas emissions, China, fulfills its climate pledge to peak carbon dioxide emissions in 2030, the positive effects would extend all the way to the United States, where improved air quality would result in nearly 2,000 fewer premature deaths.
The study estimates China’s climate policy air quality and health co-benefits resulting from reduced atmospheric concentrations of ozone, as well as co-benefits from reduced ozone and particulate air pollution (PM2.5) in three downwind and populous countries: South Korea, Japan, and the United States. As ozone and PM2.5 give a well-rounded picture of air quality and can be transported over long distances, accounting for both pollutants enables a more accurate projection of associated health co-benefits in the country of origin and those downwind.
“The results show that climate policy in China can influence air quality even as far away as the U.S.,” says Noelle Eckley Selin, an associate professor in MIT’s Institute for Data, Systems, and Society and Department of Earth, Atmospheric and Planetary Sciences (EAPS), who co-led the study. “This shows that policy action on climate is indeed in everyone’s interest, in the near term as well as in the longer term.”
The other co-leader of the study is Valerie Karplus, the assistant professor of global economics and management in MIT’s Sloan School of Management. Both co-leaders are faculty affiliates of the MIT Joint Program on the Science and Policy of Global Change. Their co-authors include former EAPS graduate student and lead author Mingwei Li, former Joint Program research scientist Da Zhang, and former MIT postdoc Chiao-Ting Li.