Can PM2.5 Impact Depression and Dementia

May 24, 2022

May is mental health awareness month. The link between mental health and indoor air quality is often overlooked. This week’s blog will discuss how elevated particulate matter might impact our mental state.

What is PM2.5

According to the Environmental Protection Agency (EPA), particulate matter (PM) is a mixture of solid particles and liquid droplets in the air. PM2.5, are fine particles 2.5 micrometers in diameter and smaller. When compared to larger particles, the EPA considers PM2.5 to pose the highest health risk due to its ability to get into the deepest regions of the lungs.

PM2.5 & Depression

According to a study conducted in 2020, PM2.5 has been theorized to influence depression and other mental health outcomes resulting from 1) oxidative stress and 2) chronic inflammation. Oxidative stress refers to an imbalance in free radicals and antioxidants when a biological system can’t remove these contaminants. PM2.5 is thought to release free radicals which may impact mental health and cause tissue damage. The study found improvements in HVAC filtration reduced depressive symptoms in environments such as cities, homes with smokers, and locations near wildfires. The study shows that PM2.5 may impact 2.7% of depression cases. A second study in China showed that a 10 microgram per cubic meter reduction of PM2.5 was associated with a 4.4% decrease in depressive symptoms.

PM2.5 & Dementia

PM 2.5 is also shown to have a link with dementia. A cohort study researched how a 10-year exposure to PM2.5 may contribute to dementia. The study accounted for demographic, geographic, and socioeconomic factors of the participants involved. The research showed a 16% increase in dementia risk for each 1 microgram per cubic meter increase in PM2.5 over 10 micrograms per cubic meter. These results possibly show a link between long term PM2.5 exposure and neurodegenerative health effects. Another study in Japan linked lower PM2.5 levels in office spaces with greater worker satisfaction with COVID-19 countermeasures and increased worker productivity.


Based on a myriad of studies, it appears that exposure to elevated levels of PM2.5 especially in the long term can impact our mental and physical health. These studies also show that decreasing concentrations through HVAC filtration can cause small improvements in these mental health outcomes. If you are concerned with the PM2.5 concentrations in your home or workplace, consider contacting an indoor air quality professional such as Indoor Science.