Being exposed to air pollution for the long term may negatively affect both physical and mental health.
PM2.5 is a form of fine particulate matter that contains tiny particles mostly from vehicles and industrial wastes. A recent study published in the Proceedings of the National Academy of Sciences journal has found that prolonged exposure to PM2.5, combined with certain genetic factors for depression, would increase the risk of social stress and cognitive problems.
In this project, there were 352 participants from Beijing, China. The city has a relatively high level of PM2.5 and air pollution.
The scientists examined specific genes of each participant, which are linked to depression, to assess their susceptibility to this mental issue.
Next, they analyzed air monitoring information collected from stations near to each participant’s home to measure how each person is exposed to PM2.5 for 6 months before the research.
The results suggested that there was a link between PM2.5 exposure and poor performance of participants on cognitive tests about problem-solving and reasoning. Prolonged PM2.5 exposure also increased the risk of anxiety-depression.
In the next step, the scientists study brain networks for processing stress information and cognitive as well as their link to genetic factors for depression and PM2.5 exposure.
They found that social stress would have a clear effect on brain networks in those with greater exposure to PM2.5 a genetic factor for depression.
The total effect of both air pollution and genetic factors was greater than the effects of every single element. This indicated that air pollution would interact with genetic factors for depression and affect brain networks.
The study implicates that people may reduce their outdoor activities if levels of air pollution are high and increase their risk. This is especially important for those with a family history of mental issues or brain disorders.
Public health experts may also make proper plans to reduce depression by controlling air pollution, especially in densely populated areas.
A significant strength of the study is that the authors have used MRI scans to examine the effects of air pollution on the brain. This is by far the most direct measurement of our brain function.
The sample also contains a large number of people, which are socioeconomically homogeneous.
However, there were several drawbacks. For instance, the study only examined certain rather than a larger number of genetic factors for depression.