Associate Professor Koichiro Ito and Will Seonmin Heo, MPP’20, Measure International Pollution Spillover Effects

Will Seonmin Heo, MPP’20, arrived at the University of Chicago from South Korea intent on pursuing his Masters in Public Policy with a focus on the intersection of environmental and economic research. In his first year, he registered for the applied econometrics course taught by Associate Professor Koichiro Ito; they connected through their shared interest in environmental policy and the effects it has on the economy.

On one particular research topic, this shared interest turned into a meaningful collaboration between the two. For several years, Ito had searched for data that could be used to study the health and economic implications of international spillovers of air pollution. The limited available data for researchers challenged his pursuit of the subject. Along with Heo, however, the two found a potential solution.

“Transboundary air pollution from China is a well-discussed topic in South Korea,” Heo said, “so I was well aware of the issue. I immediately understood what he was looking for and found good microdata on mortality and air pollution in South Korea that we could use in this study.”

Koichiro invited him to work together on this project, and their collaboration continued as Heo graduated and left to pursue his Ph.D. at UC Santa Barbara.

“We spoke for hours, learning about the new atmospheric transport model and discussing empirical strategies to make sense of the world of economics and atmospheric science,” Heo said.

To apply recent advancement in atmospheric science to their transboundary air pollution data collection efforts, they invited atmospheric science expert Rao Kotamarthi from Argonne National Laboratory to work with them. The three researchers recently published their working paper, “International Spillover Effects of Air Pollution: Evidence from Mortality and Health Data” with UChicago’s Becker Friedman Institute for Economics.

In the paper, they track how the particle pollution from China travels to South Korea. They then combine that information with mortality and emergency-room visit data from South Korea to study the relationship between pollution levels in China and health concerns for residents of South Korea.

They found in their study that transboundary air pollution from China does significantly raise the levels of air pollution in South Korea. Knowing that, when looking at individual-level mortality data from South Korea, they concluded that a 1 unit increase in transboundary pollution from China in the past 70 days resulted in an increase in hourly mortality in South Korea by 3.56 per billion people. Infants and those with respiratory and cardiovascular diseases faced even higher mortality rates as a result of the pollution.

While they demonstrate that China’s air pollution does have spillover effects and health repercussions for residents of South Korea, they also found evidence of environmental regulation policies. China’s “War on Pollution” policies have reduced the levels of air pollution in the country, resulting in a corresponding decrease in South Korea’s air pollution levels.

As air pollution poses one of the most significant environmental and health threats around the world, this paper from Ito, Heo, and Kotamarthi provides a new understanding of what one country’s environmental policies may imply for the health of another’s. “This project has come from a partnership between a Harris faculty, a Harris student, and a scientist from Argonne,” Ito said. “It would not have been possible without this unique collaboration.”