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Two researchers have found that changes in a given day's wind pattern that send pollutants in a particular direction can cause crime rates to climb and, in aggregate, lead to at least $178 million a year in crime costs nationally.

Writing in the National Bureau of Economic Research's working paper series, Evan Herrnstadt or Harvard and Erich Muehlegger of UC-Davis say that their findings suggest that governments should be placing a much greater premium on improving local air quality to create better outcomes for citizens.

The pair looked at wind patterns and crime rates on opposite sides of major expressways in Chicago.

They found that, when controlling for other factors, crime would increase marginally on the side of the freeway downwind from the expressway's auto pollution source. For example, on a day when the wind is blowing from the south, the pollution impacts the north side of expressway I-290 (the east-west red line surrounded by maroon in the chart below); and vice-versa when the wind is blowing from the north.


Herrnstadt told me by phone that being downwind from pollution on a given day could, on average, make people "that much more irritable and less able to control impulses." Someone who would otherwise commit an assault for example, might on average escalate their behavior to full-on battery if the wind has been blowing in the wrong direction, he said. As the pair note, air pollution has been found to affect physiology and cognition, usually by contributing to oxygen deficiency in the brain. We also already have evidence it can lead to depression.

"Our results suggest that pollution may affect cognition in ways that extend beyond impairing performance on standardized tests and may influence individual behavior in more subtle ways that previously considered," they conclude.

Rob covers business, economics and the environment for Fusion. He previously worked at Business Insider. He grew up in Chicago.