It has been said that depression can feel like a cloud hanging over one's head. Now, researchers have found that actual clouds — of pollution — can contribute to the development of depression later in life.
A study published in the journal JAMA Network Open links long-term exposure to air pollution with depression among older adults in the United States.
Alarmingly, the levels of pollution found to be harmful to our mental health are not particularly extreme. Researchers found a correlation between late-onset depression in Americans 64 and older and "common levels" of air pollution.
How the study was conducted
For the study, researchers from Harvard and Emory tracked almost nine million Medicare enrollees 64 and older for a period of 11 years. Of the over 8.9 million individuals studied, over 1.5 million were diagnosed with late-onset depression throughout the course of the study.
The pollution that the study's subjects were exposed to was often considered "safe," which raises the possibility that many more people around the U.S. — and the world — are at risk.
The study, which tracked three main pollutants — fine particulate matter, nitrogen dioxide, and ozone — found that exposure to all three was associated with an increased risk of depression diagnosis in older adults.
The comprehensive, years-long study has the potential to revolutionize the way scientists correlate air pollution and depression.
"Worldwide, studies have shown that exposure to air pollution is associated with an increased risk of adverse mental health outcomes, such as depression," the study's authors write. "To our knowledge, this study is the first to examine the associations between long-term exposure to air pollution and risk of late-onset depression incidence among the US older adult population (>64 years) in a longitudinal setting over a study period of more than 10 years."
What's being done about air pollution?
Unfortunately, not enough. Another study published in Lancet Planetary Health shows that almost everyone in the world is exposed to air pollution above levels deemed "safe" by the World Health Organization.
"Almost no one is safe from air pollution," the study's lead author, Yuming Guo, told the Washington Post.
Though more coordinated efforts are needed, steps are being taken at the individual, local, and global levels to reduce air pollution.
The EPA maintains a list of steps that everyone can take to reduce air pollution on an individual level, like conserving energy at home and carpooling.
Locally, cities like London have instituted Low Emission Zones where polluting cars are restricted.
Globally, pollution-removal technologies are on the rise and can even contribute to the manufacturing of carbon-negative consumer products.
Further awareness of the harmful effects of air pollution, aided by robust studies, should only serve to accelerate initiatives that will help create a cleaner planet.
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