Picture Someone Who has a seemingly flawless complexion: their skin boasts a healthy glow, firmness, regular-sized pores, and an absence of splotches or broken veins. If you don't have one of these people in your life, perhaps you've seen one or two on the street, on the subway, or in a grocery store. It seems that, if you want skin like that, you've got to pick your parents.

You've probably heard that the best defense against aging is good genetics. Perhaps this accounts for why stars such as Katharine Hepburn and Paul Newman have enviably slow-aging faces. While there is a great deal to be said about DNA, there is hope for the rest of us who were born to average-complexioned parents. Depending on the dermatologist asked, 75 to 90 percent of our skin's damage is caused by us. More specifically, it is caused by the choices we make every day.

Sun damage

According to dermatologists, the sun's ultraviolet rays are accountable for more skin damage than any other factor. These rays come in two main types: UVA and UVB. UVA rays, which can penetrate cloud cover and glass, are often referred to as long-length waves. They are present in the same intensity throughout the day, remain strong even in winter, and are responsible for skin cancer and creating skin changes such as blotchiness and collagen breakdown often associated with aging skin. How do UVA rays do this? By penetrating skin to create free radicals. It is these free radicals that wreak havoc on melanin-making cells and degrade the skin's collagen and elastin.

UVB rays are sometimes called short-length waves and are responsible for tanning, burning, and skin cancer. They are at their strongest during late spring, summer, and early fall, at locations near the equator and at higher altitudes. UVB rays are most intense from the hours of 10 a.m. to 3 p.m.

Avoid indoor tanning! Not only is the ultraviolet used by indoor tannins as dangerous as the sun's version, recent studies suggest that your chances of getting skin cancer are his her if you expose yourself to both sun only.

The effects of pollution

We know pollution is bad for the lungs, can cause teary eyes, and may contribute to birth defects. But how does pollution affect your complexion? Most dermatologists believe the answer is "adversely" That's because pollution is comprised of chemicals, such as carbon monoxide, oxides of nitrogen, lead, and chlorofluorocarbons, which set off free radicals in the skin. These free radicals lead to collagen and elastin breakdown, which in turn leads to slackness. Especially sensitive faces may find that pollution causes rashes and other allergic reactions, while oily skin may suffer from blocked pores and increased greasiness in a polluted environment.