Effects of Particulate Matter on Healthy Skin: A Comparative Study between High- and Low-Particulate Matter Periods

BACKGROUND: The influence of airborne particulate matter (PM) on skin has primarily been studied in patients with skin diseases such as atopic dermatitis. Recently, the effect of PM on healthy human skin has gained attention. OBJECTIVE: To evaluate the relationship between PM concentration and objective skin changes in healthy subjects. METHODS: This prospective study enrolled 25 healthy volunteers without any skin disease. Data regarding daily meteorological parameters and air pollution were collected during a high-PM period and a low-PM period for 14 days. Environmental and lifestyle factors that might influence skin conditions of subjects were also collected during the study period. Biophysical parameters of the skin such as transepidermal water loss (TEWL), hydration, erythema index, and melanin index were measured. Pores, wrinkles, sebum, and skin tone were evaluated using a facial analysis system. RESULTS: Mean TEWL value during the high-PM period was significantly higher than that during the low-PM period (10.16 g/m(2)/h vs. 5.99 g/m(2)/h; p=0.0005). Mean erythema index was significantly higher in the high-PM period than that in the low-PM period (4.3 vs. 3.42; p=0.038). For facial analysis system indices, uniformity of skin tone was higher in the low-PM period than that in the high-PM period (p<0.0001). In addition, with increasing PM(10) and PM(2.5), TEWL also showed increase when other environmental components were constant (regression coefficient [RC]=0.1529, p<0.0001 for PM(10); RC=0.2055, p=0.0153 for PM(2.5)). CONCLUSION: Increased PM concentrations may contribute to disturbed barrier function, increased facial erythema, and uneven skin tone even in healthy human skin.