Unfortunately, when it's gray and smoggy, you may feel like you're getting less sun, but you're actually getting more. "Pollution enhances UV damage to the skin," says Beverly Hills dermatologist Debra Luftman, M.D. The particles of pollution magnify the ultraviolet radiation -- as pollution gets worse, so does our exposure to harmful UV rays. If you live in a polluted place, Luftman says you need to be even more religious about sunblock. She recommends using a sunscreen with titanium dioxide or zinc oxide because these minerals create a physical barrier against pollution. I like Coola Mineral Face Matte Tint SPF 30, $36, which has titanium, zinc and SPF-boosting botanicals -- and gives you a hint of color. Kate Somerville Daily Deflector Waterlight Broad Spectrum SPF 50, $48, is another favorite. It has anti-aging ingredients, a light texture and absorbs quickly.

Odds are you're not going to wash your face after every time you go outside. (Nor would your dermatologist want you to -- you'd dry out your skin and damage its protective barrier.) However, Luftman has a trick that's much more doable: Use a thermal water mist. "Spray that on top of your skin throughout the day," she says. "It can help negate some of the pollution." She suggests Avene Thermal Spring Water, $9. For even more anti-aging benefits, I like Tata Harper Hydrating Floral Essence, $65, which has jasmine and hyaluronic acid for added moisture. (There's currently a limited edition rose version available that's even more phenomenal.)