Long-term exposure to pollution linked to depression, study finds

Long-term exposure to even low levels of air pollution is linked to increased incidence of depression and anxiety, a U.K. study suggests, adding to a wave of evidence that fossil fuels may be negatively impacting mental health.

Researchers in the United Kingdom and China followed nearly 390,000 adults in the U.K. for roughly 11 years and found long-term exposure to multiple air pollutants was associated with a greater risk of depression and anxiety. These pollutants – which include fine particulate matter, nitric oxide and nitrogen dioxide – are commonly emitted into the air when fossil fuels are burned for vehicles, power plants, construction equipment and industrial work.

Scientists have long raised alarm about pollution’s impact on physical health, including cardiovascular disease, respiratory infections, lung cancer and more. A University of Chicago report last year said air pollution now takes more than two years off the global average life expectancy – more than cigarettes, alcohol, or conflict and terrorism. Another recent study said that eliminating air pollution from fossil fuels would prevent more than 50,000 premature deaths and provide more than $600 billion in health benefits in the United States every year. Air pollution has also been shown to harm older adults’ brains, contributing to cognitive decline and dementia.

The study published Wednesday in the Journal of the American Medical Association Psychiatry, which took into account socioeconomic status and preexisting mental illness, supports a growing understanding among scientists that fossil fuels affect more than one’s physical health.

Potential links between pollution and mental health are “clearly a serious issue,” said Cybele Dey, a child and adolescent psychiatrist who serves as co-chair of Doctors for the Environment Australia.

“In terms of links to depression and anxiety, those findings have varied depending on the study,” she said. “There seems to be a link of some kind, but the pathway for how that link is happening is still something we haven’t figured out.”

Dey, who studies such links in children and teens, pointed to air pollution, increased heat, natural disasters and distress over climate change as potential factors that could have negative effects on mental health.

In her studies of children and teens, Dey said there has been “consistent evidence” linking air pollution to problems with learning, attention and focus. Air pollution has also been associated with lower birthweights, premature births, heart disease, lung disease, shorter life spans and a number of other factors that could negatively impact a community’s mental health, she said. Asthma, for example, can be caused by high levels of pollution and is also associated with mood disorders and other mental health symptoms. And after a gas leak led a school in Los Angeles to install air filters, researchers began to notice significantly improved test scores.

Dey also noted pollution’s potential as a disruptive force; air pollution has closed schools and led to driving restrictions in parts of Asia: “We know that, when children are not able to go to school for periods of time, that’s associated with effects on mental health,” she said.

“It’s really important for governments to be aware of the impacts,” she added, “and conversely aware of the benefits for our health of transitioning off fossil fuels and protecting people from exposure to excessive pollution.”