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.

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 to blood vessels may indirectly affect the brain’s oxygen and nutrient supply.

The 2026 brain-aging research adds to evidence that broader physical environmental conditions may influence neurological health.

However, not everyone exposed to polluted air will develop cognitive problems, and individual risk depends on many factors.

What may help: Monitor local air quality, reduce strenuous outdoor activity during severe pollution episodes, avoid indoor smoke, and use appropriate ventilation or air