Childhood exposure to air pollution may limit economic mobility in adulthood

“This study takes a major step toward filling a knowledge gap on a key link between environmental factors and long-term economic outcomes,” said Francesca Dominici, corresponding author, the Clarence James Gamble Professor of Biostatistics, Population, and Data Science at Harvard Chan School and faculty director of the Harvard Data Science Initiative. “The results suggest that air pollution can have long-lasting effects beyond its health effects—and that these effects vary by region and population.”

The study results will be published on September 9 in the journal The Proceedings of the National Academy of Sciences.

The study builds on previous research on the relationship between PM2.5 exposure and economic opportunity, using more detailed data as well as state-of-the-art causal inference methods to adjust for socioeconomic and demographic confounders. The researchers analyzed data on PM2.5 exposure and economic income from 86% of all U.S. census tracts — small county statistical divisions — from 1980 to 2010. They focused on people born between 1978 and 1983, looking at their average incomes from 2014 to 2015, when they were between the ages of 31 and 37. To measure economic mobility, they used a statistic called absolute upward mobility (AUM), which is defined as the average adult income of children born in the 25th century of a family.^t percentile of the distribution of national income.

The study found that the more a person was exposed to PM2.5 during childhood, the lower their earnings were as an adult. On average, a one-microgram per cubic meter (μg/m3) increase in PM2.5 exposure in 1982 was associated with a 1.146% lower AUM in 2015. The study also found that PM2.5 exposure had a disproportionately large impact on AUM in certain regions of the U.S., particularly in the Midwest and South.

“Our findings underscore the need to implement stringent air quality standards at national level,” said co-author Luca Merlo, a researcher at the European University in Rome. “They also suggest the need for local interventions to mitigate air pollution and integrated policies that take into account environmental and economic inequalities.”

Sophie-An Kingsbury Lee, a graduate student at Harvard John A. Paulson School of Engineering and Applied Sciences, was co-lead author.

The study was funded by the National Institutes of Health (grants R01MD012769, R01ES028033, 5R01AG060232, R01ES030616, R01AG066793, 1R01ES029950, RF1AG07437201A1, R01MD016054, R01ES034373, RF1AG080948, RF1AG071024, R01ES34021, 1U24ES035309, P30ES000002) and the Alfred P. Sloan Foundation (grant G-2020-13946).