Welcome to Sun Week on ITG, a celebration dedicated to the one part of your beauty routine you can't opt out of. (Lipstick is fun and all, but never life or death). This week, we'll be exploring everything sun protection has to offer. Oh, and we launched Glossier’s very own version! The following is a story we wrote last year about the kind of airborne, outdoor pollutants that are jonesing to mess with your skin—thousands of tiny reasons that so many sunscreens (Glossier's included) use antioxidants in their formulas, to protect and neutralize. Nothing to fear, but something to be aware of. Educate thyself:

When you move to a city, you make sacrifices. You’ll live in a tiny apartment, spend a fresh ton of money, and expose yourself to lots of stress that could have been avoided if you had stayed the suburbs. Not to complain about it or anything—the thrill of adventure takes us to brighter, louder, more expensive places—but it's important to go into city-living with your eyes open. Because beyond having to navigate a two-story Duane Reade when all you need is toothpaste, there are also different skincare concerns for city folk. Things like protection against free radicals, ozone, and floating debris (!). If the air around us isn't conspiring to kill us, at the very least, it could be leading to your acne and pre-mature aging.

If the dermatologists and aestheticians we interviewed for this story are to be believed, incorporating a defense into your routine is worth considering. But before you do, know what you're defending against (and why). Start here:

What exactly are free radicals?
They are not, as the name suggests, dangerous escaped prisoners that rob your skin of its moisture and glow as you’re walking to work in the morning. But in a way, they’re actually more insidious, because they’re already in your skin. Dr. Heidi Waldorf, Mount Sinai’s Director of Cosmetic Dermatology, explains: “Free radicals are reactive molecules—they’re created as byproducts of other processes, like photodamage and cigarette smoke.” In layman’s terms, free radicals come about when normal, happy, functioning cells are mutated by pollutants in the gross urban air (New York, we love you!). As a result, they become less happy. And prone to age us and dry us out.

So, what is there to do?
UV rays are a big trigger for cell mutation, so start with SPF. But if you’re reading ITG, you’re probably already working on that. (If not, let’s get you started). After that, reach for antioxidant-rich products. New York Dermatology Group’s Dr. Jessica Weiser suggests ingredients like vitamin C, vitamin E, argan oil, green tea, and coffeeberry. The idea is protect the rest of your cells from free radical damage, while also preventing the formation of new free radicals.

Serums, those little targeted treatments you can apply post-cleanse and pre-moisturizer, come in clutch here. Grown Alchemist’s Antioxidant Serum makes for a great, lightweight barrier that pairs well with anything and leaves you feeling a little brighter when you head out into the world. If your skin requires something heavier (or you’re in the market for a new and more targeted face cream), Decorté’s Environmental Day Cream is a richer option. As is true with sunscreens, consistency is less important. What is important is getting your skin the ingredients it needs.

But I don’t live in Hong Kong or Los Angeles—I’m safe, right?
If only this were true, perhaps we’d all be wise enough to join Martha Stewart on her giant farm upstate, living off the land. Sadly, no. Dr. Waldorf mentions that while urban dwellers are exposed to heavier concentrations of pollutants, less population-dense areas aren’t safe zones. “Wind systems move pollutants—they’re a problem everywhere,” she says. The suburban minimalist among us might lean towards a weekly treatment like an antioxidant mask. Plant Apothecary makes a powerful (and very reasonable) Matcha Powder Mask, which is literally green tea for your face. Kiehl’s Cilantro and Orange Extract Purifying Mask also guards against pollutants and isn’t a daily treatment. Neither can be classified as easy to apply (one is a powder you measure out in tablespoons; the other requires two stages of saturation and a little commitment) but both are highly nutritious.

Can I protect and cleanse at the same time?
If you believe in yourself, sure! If you really want to get defensive, Dr. Weiser suggests switching out your nightly cleanser for a micellar water or heavy-duty oil to take care of soot and debris.

OK enough about skin—what about my mind?
We don’t need to tell you that living in an urban environment is probably, maybe, a little bit more stressful than living somewhere else—Joan Didion has already written that book. But stress, which is even more evil than free radicals and ozone and secondhand smoke, plays a huge role in damaging your skin. Especially because free radicals have been linked to anxiety and emotional stress, according to the NIH. Few things substitute a killer eye cream like regular sleep and exercise, especially if you find yourself in a high-intensity city (again, New York, we love you!!) But if you can afford a country house, maybe do that, too.

Hanne Gaby Odiele photographed by Emily Weiss.

Or you could skip town entirely. In the spirit of vacation, read up on what products to bring to this beach with a postcard from Glossier's Claire Knebl.

It's still Sun Week! Read all about it.