Long-term breathing of polluted air increases the risk of depression, according to two large recent studies, adding to growing evidence of the harmful effects of pollution on mental health.
The first study, published last week in the journal JAMA Psychology, included a group of about 390 people in the UK who were studied for about eleven years. Their exposure levels were estimated based on their home addresses.
The researchers studied the levels of particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2) and nitric oxide (NO), which are polluting gases from fossil fuel power plants and road traffic.
The researchers concluded that “long-term exposure to multiple pollutants is associated with an increased risk of depression and anxiety.”
“While air quality standards in many countries still far exceed the most recent recommendations reported by the World Health Organization in 2021, more stringent pollution standards or rules should be defined,” the study authors said.
As for the second study, published Friday in the journal “Jama Open Network”, it focused on the effect of fine particles (PM2.5), nitrogen dioxide (NO2) and ozone (O3) on people over the age of 64.
The aim was to study the effect of air pollution on suffering from depression in an advanced stage of life.
The study was based on a database from “Medicare”, a health insurance system for the elderly in the United States, and included 8.9 million people, including 1.5 million suffering from depression.
The result again showed a strong link between pollution and depression, specifically by monitoring levels of particulate matter and nitrogen dioxide in poor people.
This link may be explained by the relationship observed between higher concentrations of pollutants and inflammation in the brain, according to the two studies.
“There is a strong link between inflammation and depression,” said Oliver Robinson, a professor of neuroscience and mental health at University College London who was not involved in the studies.
He added that the results of the two studies “add to the growing evidence that we should be concerned about the effects of pollution on mental health, in addition to the clearer links between pollution” and respiratory diseases.