Short-term effects of exposure to air pollution on biophysical parameters of skin in a panel of healthy adults.

Little research on impact of air pollution on human skin is available. We aimed to clarify the association between acute exposure to criteria air pollutant with biophysical characteristics of the skin. We followed a panel of 20 volunteers free of any skin diseases in skin evaluation study in Tehran, Iran from April 2017 to April 2018. Two distinct body parts including middle forehead and inside the right upper arm were evaluated at six time periods. The associations of the weighted averages of personal exposure to air pollutants at 24 hours up to 6 days, and multiday average before the skin assessment with biophysical characteristics of normal skin including sebum content, hydration, transepidermal water loss (TEWL), erythema index, melanin index, pH, temperature, friction, and elasticity were assessed in a random intercept linear mixed effects modeling approach. We observed significant positive association for the arm sebum content with exposure to PM , and SO ; the arm and forehead TEWL with NO , the arm and forehead friction with O , and forehead hydration with PM and PM in early lags. We found significant negative association for the arm melanin index, elasticity, and erythema index with exposure to O ; and forehead elasticity with PM and PM . Our results provided some evidence that short-term exposure to particulate and gaseous air pollutants have detrimental effects on biophysical and biomechanical properties of skin. The association varied across body area and depended on pollutant type.