A new analysis of the Air Quality Life Index (AQLI), produced by the Energy Policy Institute at the University of Chicago (EPIC), shows the average South Korean can expect to lose 1.4 years of life expectancy because air quality fails to meet the World Health Organization’s (WHO) guideline for fine particulate pollution. The capital Seoul, the largest city and home to about 10 million people, has the nation’s worst pollution. The average resident will live 1.7 years less if the city’s high pollution levels continue relative to if the WHO guideline was met. South Korea’s particulate pollution is now twice the average for the 36 member countries in the Organization for Economic Co-operation and Development (OECD).

“As countries navigate the dual challenges of sustaining economic growth and protecting the environment and public health, the AQLI shows not only the damage caused by pollution but also the enormous gains that can be made with policies to address it,” says Michael Greenstone, the Milton Friedman Distinguished Service Professor in Economics at the University of Chicago, who created the Index along with his colleagues at EPIC.

The AQLI finds that in 2016, 100 percent of South Korea’s 50 million people lived in areas where the annual average particulate pollution level exceeded the WHO guideline. While the western part of the country is the most polluted, with the highest levels of pollution in the northwestern provinces, the country’s southwest has seen the greatest increase in particulate pollution in recent years. From 1998 to 2016, residents in the Jeollabuk and Jeollanam provinces lost up to 0.9 years of life expectancy.

The AQLI is based on a pair of peer-reviewed studies in which Greenstone and his co-authors exploited a unique natural experiment in China. By comparing a set of the population that was exposed to prolonged exposure of high levels of pollution to those who were not, they were able to isolate the effect of air pollution from other factors that affect health, and to do so at the very high concentrations that prevail in China, South Korea, and other countries today.

Greenstone then combined the results from these studies with hyper-localized, global particulate matter measurements, allowing users to zoom in on any district in the world and understand the impacts of that district’s local air pollution on life expectancy. This improves upon the existing AQI (Air Quality Index), which translates air pollution concentrations into colors without shedding light on what those colors mean for people’s wellbeing.