The study found that women exposed to higher levels of air pollutants were more likely to have facial pigment spots and more pronounced nasolabial folds. The results firmly established environmental pollutants as important skin-aging factors.

The environmental impact of skin aging will likely worsen. Although overall air quality in the United States has improved since the 1970s, measurable levels of pollutants persist. Several places in the world have experienced increased air pollution and, since air currents freely cross international borders, dealing with the harmful effects of pollutants has become a global issue.

Identifying the Bad Actors
Air pollutants come in a wide variety of gases, particulates, and chemicals, all of which can come into contact with skin.

Ground-Level Ozone
Ground-level ozone, the major component of smog, forms from the reaction of sunlight with nitrogen oxides and organic compounds. Extended exposure to inhaled ozone results in increased oxidative stress and results in inflammation throughout the body. Ozone exposure can also deplete natural skin antioxidants and oxidize skin lipids, leading to a compromised barrier.

UVB Radiation
Although ground-level ozone can be harmful, the ozone layer in the upper atmosphere prevents more than 90 percent of UVB radiation from reaching Earth's surface. UVB is the wavelength of light that causes sunburn, increased melanin synthesis (tanning), and contributes to skin photoaging. The ozone layer has become thinner in recent decades, potentially exposing people to increased amounts of harmful ultraviolet light.

Polycyclic Aromatic Hydrocarbons
A diverse group of chemicals called polycyclic aromatic hydrocarbons originates from the incomplete burning of fuels, such as coal, gas, or oil; 90 percent of indoor polycyclic aromatic hydrocarbons is due to tobacco smoke. These compounds bind to a cellular receptor on skin cells. This binding stimulates the production of melanin and its visible effect of darker skin pigmentation.

Dust
Dust produced by the braking systems of cars and mass transit vehicles contains compounds with metals, such as iron, copper, and zinc. These compounds also contribute to oxidative stress and inflammation.

Fighting Back to Protect the Skin
Taking care of the skin means taking steps to minimize unnecessary exposure to pollutants, such as avoiding high-traffic areas and smoky rooms.
Let your eyes and nose be your guide. If clients can see a haze or smell car exhaust, then their skin is at risk! A daily skin care regimen that can fight the effects of pollutants, free radical production, and ultraviolet exposure is essential.

Use a facial cleanser before bed to remove dust and dirt particles that are sitting on skin. Follow up with a toner with antioxidant ingredients, such as vitamin C and E, green tea extract, or grapeseed extract.

An antioxidant-rich daytime moisturizing face cream protects skin from oxidative stress caused by pollutants and restores barrier function.
The use of skin and lip care products with broad spectrum sunscreen will help to prevent photoaging.

An ounce of prevention is better than the cure. Taking the extra steps to protect the skin before exposure is key to keeping the skin tone bright and clear and the skin looking more vibrant.

References
Grigoratos T. and Martini G. (2015) Brake wear particle emissions: a review. Environ Sci Pollut Res Int. 22: 2491–2504.
Lodovici M. and Bigagli E. (2011) Oxidative Stress and Air Pollution Exposure. J Toxicol Vol 2011, Article ID 487074.
Vierkötter A1, Schikowski T, Ranft U, Sugiri D, Matsui M, Krämer U, Krutmann J. (2010) Airborne particle exposure and extrinsic skin aging. J. Invest Dermatol 130(12):2719-26.