Air pollution contains a myriad of toxic substances. Exposure to air pollutants is associated with poor health outcomes and increased risk of disease. Findings from a recent review and meta-analysis suggest that high concentrations of particulate matter in air pollution may increase the risk of developing depression.

Depression is the most common mental health disorder worldwide, affecting approximately 322 million people – more than 4 percent of the global population. Between 2005 and 2015, rates of depression increased by more than 18 percent, and public health experts predict that by the year 2020, depression likely will rank second in the global burden of disease.

Particulate matter in air pollution is a mixture of solid particles and liquid droplets. Some evidence suggests that exposure to particulate air pollutants accelerates aging.

The authors of the review conducted a meta-analysis of 14 studies involving more than 680,000 participants living in North America, Europe, and Asia. They found that as concentrations of particulate matter increased, the risk of depression and suicide increased. Specifically, for every 10 microgram per cubic meter increase in particulate matter that is 2.5 microns or less in width, the risk of depression increased by 19 percent and risk of suicide increased by 5 percent.

The mechanisms that drive these links may be related to increased oxidative stress and neuroinflammation as a consequence of exposure to air pollutants. These findings point to the need for improving air quality and monitoring at-risk groups living in areas where air quality is poor.

• Link to full study.
• Link to FMF overview article about depression.