Does urban pollution accelerate the ageing of your skin?

Chronic exposure to fine particulate matter from city air accelerates visible skin ageing. In 400 older women who had lived for a long time near heavily trafficked roads, researchers observed 20% more pigmentation spots on the forehead and cheeks. The effect on wrinkles was less clear-cut. These are observational associations, not proof that pollution is the sole cause.

Biologically, there is a well-defined mechanism. Fine particulate matter increases the production of free radicals in the skin, which causes inflammation and activates enzymes that break down collagen. This leads to looser skin and pigmentation changes. Laboratory research on human skin cells confirms this pattern, but that is different from clinical evidence in real people.

UV radiation and fine particulate matter amplify each other's damage. Laboratory studies show that the combination of both considerably increases oxidative stress, DNA damage and cellular ageing in pigment cells. A study of taxi drivers who drove daily in city traffic found a weakened skin barrier and lower antioxidant capacity in the skin compared with colleagues in rural areas. Wrinkles and spots were not noticeably worse in that group, however, most likely because sun exposure played a larger role.

Protection against it remains a largely open question. Laboratory research shows that an antioxidant from green tea (EGCG) can reduce the damage caused by fine particulate matter to skin cells and inhibits collagen breakdown. However, there are no good studies in real people yet that confirm this. Whether drinking green tea or using a cream containing this ingredient helps is therefore still unknown. The most concrete pointer that current knowledge offers is this: limit combined exposure to fine particulate matter and sun, because that combination appears more harmful than fine particulate matter or UV radiation separately.