This page was translated automatically from Turkish. Read the original
← Back to blogThe air you breathe shapes your mental health
City air affects more than your lungs — it plays a bigger role in depression, anxiety, and dementia than we might think.
Ultrafine particles known as PM₂.₅ are approximately one-thirtieth the width of a human hair. Because they are so small, they pass directly from the lung alveoli into the bloodstream, cross the blood–brain barrier, and have been shown to accumulate in neural tissue in human brain models. Particles that reach the brain activate microglia, triggering chronic low-grade neuroinflammation; stimulate the HPA axis, disrupting cortisol regulation; and place neurons under strain through oxidative stress.
In a UK Biobank cohort study of 389,185 people published in JAMA Psychiatry (Yang et al., 2023), long-term exposure to high levels of air pollution was associated with a 16% increase in the risk of depression and an 11% increase in the risk of anxiety. The dose–response curve is steep even at low levels — making it difficult to claim that there is a "safe threshold." Globally, approximately one-third of the stroke burden and one-fifth of the dementia burden can be attributed to air pollution (Béjot et al., Int J Stroke 2018).
The good news: this is a modifiable psychiatric risk factor. Lancet listed air pollution as one of the 12 modifiable risk factors for dementia. In China, a 10 µg/m³ reduction in PM₂.₅ was associated with a significant decrease in depressive symptom scores (Xue et al., Lancet Reg Health 2020); in Mongolia, HEPA filter use during pregnancy was associated with an average 2.8-point increase in children's IQ scores at age 4 (Ulziikhuu et al., 2023); and a one-hour walk in nature was associated with a significant reduction in stress-related amygdala activation (Sudimac et al., Mol Psychiatry 2022).
What we can do: monitor the daily air quality index, avoid peak traffic hours, use indoor ventilation with HEPA filtration, spend at least 2 hours a week in green spaces, and use a lower alert threshold for pregnant people, children, and older adults. Individual precautions matter — but they cannot replace collective solutions (emission reductions, clean air policies, and urban planning).
Clean air is not just a matter of lung health; it is a matter of mental health.