Here’s another reason to fight air pollution in your neighborhood: Dirty air means more suicides.

At least that’s the conclusion from a couple new studies. NewScientist reports that Chang Soo Kim of Yonsei University in Seoul looked at more than 4,000 suicides from seven South Korean cities — linking them to measurements of PM10 — a.k.a. “airborne particles with a diameter of 10 micrometres or less, which include the soot from vehicle exhausts.” The findings were gloomy:

Kim’s team found that suicides were more common in the two days following a spike in pollution. They considered PM10 measurements on a scale from the highest and lowest levels recorded, calculating that people were 9 percent more likely to kill themselves following a spike in pollution rising across the middle 50 percent of recorded values. For people with cardiovascular disease, which has already been linked with particulate pollution, the increase was almost 19 percent.
Most people already know that air pollution is linked to higher asthma rates. Asthma is painful in and of itself, but a study from a team led by by Ying-Chin Ko of Khaohsiung Medical University in Taiwan brings even sadder news for asthmatics: “The researchers show that suicides were more than twice as common among those with asthma — and the more severe their symptoms at the start of the study, the higher the risk.”

What makes suicide rates go up when air pollution gets worse? Reports the New Scientist:

Where air pollution is involved, the problem may not only be that as people’s physical symptoms worsen, they become more distressed. Kim suggests that PM10s may also cause nerve inflammation, affecting mental health through a direct biological mechanism.
Getting out in nature makes people happier — but apparently not if the outdoor air is not so ... natural. Stay happier by getting involved with your local, air-friendly environmental organization.
Air pollution and asthma linked to suicide
New studies find that when air quality gets worse, suicide rates go up.