Pollution exists in two forms. Primary pollution is directly linked to human activity: cars, industry, heating, etc. Secondary pollution mainly consists of ozone, which is generated after primary pollution is mutated by UV rays and heat; in other words, the famous 'greenhouse effect'. Pollution is largely composed of gases: ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide. Other components include fine particles, dust, heavy metals and volatile, organic compounds (benzene, hydrocarbons, etc).
Carbon monoxide causes cellular hypoxia. This means pollution prevents oxygenation, choking our skin in the process. The skin's metabolism slows and the consequences become visible on the surface: dullness, dryness and wrinkles. In addition to preventing the oxygenation of the skin, particles that clog the pores are deposited, resulting in the appearance of imperfections and an uneven skin tone. As for sulphur dioxide, it breaks down the skin's hydrolipid film. The skin becomes hypersensitive, irritated and allergy-prone. The negative effects of sulphur dioxide are amplified by ozone. Combined, they lead to skin inflammation. Pollution, free-radicals and UV rays cause oxidative stress, which damage the skin's cells. Affecting both the epidermis and the dermis, this stress is responsible for prematurely ageing skin. Collagen fibres and elastin are damaged, the face looses suppleness and wrinkles deepen.
Proper hydration helps fight against the harmful effects of pollution. The better you moisturise your skin, the harder it is for toxins to permeate its layers. Fortunately, a new generation of 'anti-pollution' cosmetics has been developed. Rich in antioxidants (polyphenols, tannins, niacinamide, vitamin B3) and flavonoids, they act as a protective shield. Finally, using a sunscreen is paramount in order to prevent oxidation caused by UV rays. Also, don't forget to thoroughly cleanse your skin at the end of the day. It will get rid of the impurities, toxins and dust that have accumulated throughout the day.