Pollution has a big impact on skin cells, this negative impact can be seen on the skin's surface, namely the stratum corneum. This outer layer is normally colonised with microorganisms known as microbiome. In the presence of pollutants, the skin microbiome changes for the benefit of pathogenic bacteria. Environmental contamination enhances the production of reactive oxygen species (ROS), which depletes the content of antioxidants in the skin. This causes disturbance in the redox (reduction–oxidation reaction) balance, causing stress to the skin cells. Some pollutants permeate through the stratum corneum into deeper skin layers.

The alterations of microbiome and oxidative stress, cause the induction of an inflammatory cascade in the skin. The increased production of pro-inflammatory cytokines, greatly impacts the biological function of the cells, resulting in skin lesions and deterioration of skin appearance.

Pollution also causes a negative impact on other skin properties, which are necessary for proper skin function and health. Most importantly, the environmental contaminations influence composition of skin lipids:

  • The ratio of lipids is disturbed
  • The cholesterol content is decreased
  • The sebum secretion rate is higher
  • The oxidation of lipids and proteins in the skin also occurs
  • After exposure to pollution, the skin is characterised with increased pH and lactic acid content
  • Over production of pro-inflammatory factors are related to inflammatory skin diseases, skin ageing, and skin cancer.

REFERENCES:
The Impact of Pollution on Skin and Proper Efficacy Testing for Anti-Pollution ClaimsJadwiga Rembiesa, Tautgirdas Ruzgas, Johan Engblom, Anna Holefors
http://www.mdpi.com/2079-9284/5/1/4