STUDY: How Cars Are Making Us All Depressed (Even If We Don’t Drive) - Streetsblog
Now we finally know why so many city dwellers are depressed — and no, it’s not because of your failing local sports teams.
A new study from King’s College of London found that even tiny increases in vehicle emissions in highly polluted neighborhoods were correlated with shockingly high rates of clinical depression among residents — even when the researchers controlled for common environmental contributors to mental health conditions, like lack of access to mood-boosting green space or substandard housing.
Though all the regions the researchers studied had high rates of vehicle-related pollution, people who lived in neighborhoods that had just 3 micrograms of nitrogen dioxide more per cubic meter had a stunning 39 percent higher risk of a depression diagnosis, when compared with the residents of neighborhoods with the lowest levels of NO2, which is commonly found in diesel exhaust emitted by heavy trucks.
But when the researchers looked at the kind of small particle pollution most commonly emitted by passenger vehicles, they found even more reasons to worry. Increases of just 5 micrograms per cubic meter were associated with an 18-percent spike in common mental health problems that, if left untreated, can increase the risk of suicide and destroy our quality of life.
Of course, when it comes to pollution, a lot of U.S. cities are solidly worse than London. On its worst air quality day last year, small particulate concentrations in the Big Smoke reached as high as 80 micrograms per cubic meter: more than twice the level recommended by the World Health Organization, and well above the neighborhoods for which the King’s College researchers found the lowest exhaust-related depression risk, which had just 29 micrograms. On Los Angeles’s worst day, by contrast, small particulate concentrations reached a whopping 106 micrograms. Transit-rich Manhattan had a concentration of just 41 micrograms at its smoggiest, but that’s still a full 6 micrograms higher than the WHO’s guidelines — more than enough to cause a spike in locals’ depression rates. (No wonder there are so many psychoanalysts in Woody Allen’s backyard.)