Skin Ageing and Air Pollution
Recent evidence indicates that air pollution can not only affect our respiratory and cardiovascular systems but can also exert adverse effects on human skin.
Air pollution is a contamination of either the indoor or outdoor environment by any chemical, physical, or biological agent.
Air pollution is currently considered the world’s most significant single environmental health risk factor. In 2013, the International Agency for Research on Cancer (IRAC) classified outdoor air pollution as carcinogenic to humans.
Air pollution is mainly composed of: particulate matter in various sizes (PM10, PM2.5, or smaller) and gases (O3, NOx, NO2, and CO2). Small particles are typically produced by combustion and the larger ones by mechanical and combustion processes.
Under certain atmospheric conditions, photochemical reactions take place between pollutants (e.g., NO2) and ultraviolet (UV) sun radiation and one of the main products is ozone, which leads to lung inflammation. These pollutants remain low in the atmosphere (troposphere) and settle both in urban and rural areas, forming so-called smog.
In cities, most air pollutants are caused by combustion processes from industry or road traffic. The different emission sources can influence the composition, effect, and size of the particles. The smaller the particles, the most dangerous they are.
Numerous epidemiologic studies have demonstrated the associations between short- and long-term exposures to ambient air pollution and increased risk for cardiovascular events, including myocardial infarction (MI), congestive heart failure (CHF), and stroke.
In urban areas, additional high NO2 values are added by diesel engines, which can negatively impact air quality.
Ageing is accompanied by progressive deterioration of structure and function of all tissues, including visible signs of skin ageing. Among all organs, skin is the most visible, and skin ageing directly impacts individual self-esteem.
This is illustrated best by the fact that the market for cosmetic and medical products devoted to the prevention and treatment of skin ageing has 15 billion US$ worth of sales worldwide. Signs of skin ageing might further serve as a mirror reflecting internal ageing processes of the human body with the peculiarity that skin ageing signs are directly visible and can be studied noninvasively .