Being Around Cars is Bad For Your Mental Health

A new study finds that air pollution from car exhaust increases depression.

Air pollution monitoring in Progress

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Yet another study finds that small increases in air pollution can have significant adverse effects on mental health. This study, led by Dr. Ioannis Bakolis of King's College London, examined residents of Southeast London and found that increases in particulate matter smaller than 2.5 micrometers (PM2.5), nitrogen dioxide, and other oxides were associated with 18 to 39% increased odds of common mental disorders, and particulate matter smaller than 10 micrometers (PM10) was associated with a 33% increase in psychotic experiences.

This correlation was also found in an American study which suggested a significant link between exposure to environmental pollution and an increase in rates of neuropsychiatric disorders. And if that is not depressing enough, there is research suggesting that air pollution may make COVID-19 more deadly and that noise from traffic increases the rate of Alzheimer's.

Nitrogen dioxide comes mainly from diesel exhaust, although it also comes from cooking with gas, which almost everyone in London does. The particulate matter (PM) comes mainly from tire and brake wear, although also can come from cooking and from burning wood. However, the study found profound differences between areas with low and high levels of traffic and pollution from cars.

The study involved interviews of residents and took into account many variables, from age to smoking status to alcohol use to physical activity to socioeconomic status; they even modeled traffic noise and "neighbourhood levels of deprivation, perceived neighbourhood disorder."

They conclude that there is a twofold increase in terms of common mental disorder cases directly attributable to residential annual exposures to PM2.5 greater than 15.5 micrograms per cubic meter (μg/m3), which is not actually that high, and is below the EU value air quality target value of 25 μg/m3. The American standard set by the EPA calls for an annual limit of 12 μg/m3 and a 24-hour limit of 35 μg/m3, which hasn't been changed since 2006 and is way up there at levels that could cause common mental disorders. Levels in cities all over the USA are often higher than the EU limit.

The study authors are pretty forceful in their recommendations:

"There should be special attention for innovative measures to improve air quality, such as the Ultra-Low emission Zone in London (ULEZ), the introduction of buses and cars powered by electricity and boldly rethink the way that we plan our car-less visions of cities—an urgency which will be more apparent during the aftermath of the COVID-19 pandemic era. Improving air quality is a tractable, though complex issue, and therefore measures to reduce air pollution overall within cities or to reduce individuals’ exposures through behaviour change may represent a potentially impactful primary health measure to mitigate against mental disorders within the urban population."
Extinction Rebellion protesting air pollution

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Activists in the UK are taking air pollution seriously. In the United States, not so much. One would think that all this evidence piling up about the dangers of PM2.5 pollution would actually get people thinking about regulating it more tightly and reducing standards, but it's not happening in the U.S. Andrew Wheeler of the EPA says “There’s still a lot of uncertainty” about the research. The VP of the American Petroleum Institute, a totally disinterested observer, is quoted in Science earlier this year saying "Many industry organizations agree that EPA’s proposed rule is a smart balance that will further reduce emissions and help protect public health while meeting America’s energy needs."

In other words: Sorry, cars come first.