Why air pollution may increase crime.

Air pollution costs the world approximately $5 trillion a year, or about 7 percent of global GDP, according to the World Bank. This cost is measured in a range of metrics, including lives lost and declines in health and productivity. Such pollution can be seen, felt, smelled, and even tasted. It stings and blurs the eyes, blackens the lungs, and shortens the breath. Even in the United States, about 142 million Americans still reside in counties with dangerously polluted air. Yet air pollution affects more than just our health and our natural environment: Our research shows that air pollution also has a moral cost.

Without even realizing it, people around the world may be affected, morally, by air pollution. Recent data on daily changes in wind direction in Chicago and Los Angeles suggest that air pollution increases violent crime. Using both archival and lab data, we took a closer look at the link between air pollution and unethical behavior, finding that the experience of air pollution increased unethical behavior.

In our research, we first analyzed nine years of data on nearly 10,000 U.S. cities to examine how air pollution influences different crime categories, including murder, robbery, aggravated assault, and burglary. We ruled out many important factors that might explain the relationship between air pollution and unethical behavior, such as a city’s population, law enforcement, demographic composition (e.g., median age, gender, race, education), income, poverty, and unemployment. Over and above these other factors, we found that high levels of air pollution were linked to increases in six crime categories, including murder, robbery, aggravated assault, and burglary…

Our research offers another compelling reason to work on reducing air pollution. When environments are less polluted, they are not only healthier, but also safer. The marginal dollar invested in cleaning our collective skies appears to have larger effects than policymakers thought. And these effects are not just felt in our health and in our economic lives, but in our moral lives as well. The purer our air, the purer our actions.

Jackson Lu, Julia Lee, Francesca Gino, & Adam Galinsky. Reproduced with permission. Copyright © 2018 Scientific American, a division of Nature America, Inc. All rights reserved.