You may be 40 years old, but could your brain already be showing signs of accelerated aging? New research involving more than 18,000 people suggests that the answer may depend on much more than genetics or your date of birth.

with respiratory problems.

But researchers are increasingly investigating its potential effects on the nervous system.

Fine particulate matter, commonly called PM2.5, consists of extremely small airborne particles that can be inhaled deep into the lungs.

Long-term exposure has been associated with cardiovascular disease, inflammation, and adverse health outcomes.

Some studies also link air pollution exposure with poorer cognitive outcomes

and increased dementia risk.

Several biological mechanisms are being investigated.

One possibility is that pollution-related inflammation and oxidative stress may contribute to vascular and neurological changes.Another is that damage