The United States Environmental Protection Agency (EPA) classifies pollutants into 6 distinct categories including:
A study assessed the influence of air pollution on skin aging in 400 Caucasian women aged 70-80 years who were equally distributed between rural and urban areas of Germany.1 Skin aging was clinically assessed by means of SCINEXA (score of intrinsic and extrinsic skin aging), a validated skin aging score. The measurement of air pollution was ascertained by the following:
Findings demonstrated the presence of pigment spots on the forehead and cheeks as well as wrinkles on the nasolabial folds in women living in heavily industrial areas compared to those women living in rural areas.1 The higher the soot concentration in the air, the higher the rate of developing lentigines on the cheeks.
A study about the living conditions, the sun exposure and skin aging (evaluated by means of SCINEXA) in two large ethnically different cohorts (Caucasians and Asians) revealed an association between the increase in NO2 and pigment spot development on the cheeks of women in both study populations.2 An increase of 10 μg/m³ in NO2 was associated with 25% more pigment spots in German women (p = 0.003) and with 24% more pigment spots in Chinese women older than 50 years (p <0.001).
Additional epidemiological studies have confirmed that chronic exposure to traffic-related air pollution is associated with more facial lentigines.3-8
The repetitive application of diesel exhaust particles (DEP) on human ex vivo skin models demonstrated a significant darkening of skin after 2 treatments with more darkening after repetitive applications. Histologic samples stained with Fontana Masson demonstrated a significant increase of melanin presence in the DEP models compared with untreated models. Further investigation demonstrated the inducement of tanning in DEP treated skin. To determine if this was a barrier specific issue, an in-vivo protocol was established (Düsseldorf Pollution Patch Test) which demonstrated the same darkening of skin color. The epidemiological and mechanistic studies show that there is a cause and effect relationship between air pollution and skin aging/skin pigmentation.
In humans, it is believed that eumelanin may play a role in the antioxidant strategy. In the in-vivo model, the application of DEP immediately depleted α-oxidants from the skin, as demonstrated by Raman spectroscopy. In the ex-vivo model the application of DEP caused lipid peroxidation demonstrating the presence of oxidative stress. The tanning response was able to be prevented with the use of an antioxidant containing cosmetic product.
Present disclosure: The presenter disclosed that he was a consultant to/or IUF received funding from Amway, Allergan/Skinceuticals, Beiersdorf, bitop, Blue Lagoon, Estee Lauder, Evonik, Galderma, Henkel, Horphag, ISDIN, Kiessling, Lancaster-Coty, LaRoche-Posay, L’Oreal, Lycored, Mary Kay, Procter & Gamble, Repairogen, Replicell, Stada, Symrise, Unilever, Vichy, Walgreen-Boots-Alliance.
Written by: Debbie Anderson, PhD
Reviewed by: Victor Desmond Mandel, MD