Pollutants (tiny particles like PM2.5 and PM10) in urban or smoggy environments can:
Settle on the scalp and hair shafts
Cause oxidative stress and inflammation in hair follicles
Weaken keratin (hair protein) and slow growth
✔️ A 2019 study found that exposure to particulate matter decreases important hair proteins and increases fragility.
In northern cities during winter, smog + dryness is especially rough on the scalp, worsening dryness and promoting hair fall.