Study design for anti-pollution claims

 Whereas some effects are relatively minor, long-term or acute exposure to pollutants may either aggravate existing medical conditions or induce major problems such as respiratory and cardio-vascular illnesses, neurological disorders, development disorders or tumours to cite a few. Ultimately pollution is responsible for a large number of premature deaths (the World Health Organization has recently warned that air pollution claims the lives of approximately seven million people every year in the world).

Skin, as the external envelope of our body, is directly exposed to all sources of pollutants and environmental stress factors. Some stressors have a natural origin. This is the case of UVB and UVA radiation from the sun which induce well-characterised shortand long-term deleterious effects upon the skin. But when we think of pollutants, we think of those of anthropic origin. Water pollution is a major human health issue which also has cutaneous consequences such as skin irritation and rashes. However when it comes to the investigation of the impact of pollution on the skin, and on the evaluation of anti-pollution claims substantiation, air pollution comes first. Therefore this article will focus on air pollutants, their demonstrated cutaneous effects, and on the methods available for the assessment of anti-pollution claims. 

With regards to air pollution, exhaust fumes from motor vehicles and industrial dumping are the most important contributors. According to the World Health Organization there are six major air pollutants: particulate matter (fine and coarse particles), ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. Additionally there is clear evidence that volatile organic compounds such as polycyclic aromatic hydrocarbons (PAH) and a lifestyle including a smoking habit negatively affect skin.