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Brian Lehrer: Brian Lehrer on WNYC. For this membership drive, we're ending each show with a 10-ish minute explainer on how to take care of yourself now that our listening area is slowly emerging from the pandemic. We pick five different topics based on what we've been hearing from you and seeing around the internet. Now that vaccinated people are going mask-less outdoors just in time for summer and your nose is seeing UV rays, maybe for the first time since 2019, we now turn to sunscreen, which is actually a very serious issue.

According to skincancer.org, 1 in 5 Americans will develop skin cancer by the age of 70 and more than 2 people die of skin cancer in the US every hour. Joining me now to talk about how to protect your skin from harmful UVA and UVB rays as the weather gets nicer is board-certified dermatologist, Dr. Shereene Idriss, who was coming back to the show. Dr. Idriss, welcome back to WNYC.

Dr. Idriss: Hi, Brian. Thank you so much for having me.

Brian Lehrer: Fans of your popular social media accounts will know that you extol the virtues of sunscreen. Question, do people need to wear sunscreen every day, even if it's overcast outside?

Dr. Idriss: This is a question that comes up time and time again, and the answer is very simple and straightforward. Absolutely. Unless you're working in a black cave with zero exposure to sunlight, then you can probably get a pass. As long as you're working indoors next to a window, coming and going from office to home or wherever it is, you always need sunscreen, rain or shine.

Brian Lehrer: Has the pandemic changed the need for sunscreen in any way?

Dr. Idriss: It's a really interesting question because people were obviously wearing masks for much more and thinking that the mask itself was protecting their face. Even with that, you can definitely still get some UV exposure. I think good habits are hard to break. I would always just encourage my patients to wear sunscreen even though they're wearing a mask.

Brian Lehrer: I'm going to give you a true confession story because I'm usually very good at not wearing sunscreen. I went out for a long hike the other week and I felt, "Well, I'm wearing a mask, so I don't need sunscreen." Boy, did I get a sunburn on the back of my neck? Oops. Something to remember.

Dr. Idriss: You got laxed, you got laxed like the majority of people. I'm a little bit of a militant when it comes to sunscreen, rain or shine, mask or no mask.

Brian Lehrer: What are some key things that people need to look out for when buying sunscreen?

Dr. Idriss: I think the basic things are what people need to understand. Number one is SPF coverage. I think as a rule of thumb, anything between 30 to 50 is going to keep you in the safe zone because with that coverage, you'll get 97% to 98% protection. I think the second thing which is often overlooked is whether or not a sunscreen is broad spectrum. Sunscreen alone protects against UVB, but not necessarily UVA, unless it is marketed and shown to be broad-spectrum, then for sure you're getting coverage against those types of UV.

Then I think whether or not, depending on the activity that you're doing, is the sunscreen water-resistant? Water-resistant does not mean waterproof. You're going to still need to reapply. Finally, chemical versus physical. If you're a real skin nerd, then you can go into a deep dive between the two, but understanding if something is a chemical sunscreen or a physical.

Brian Lehrer: Can you break down UVA and UVB rays? What are they? Do they harm the skin in different ways?

Dr. Idriss: UV basically stands for Ultraviolet. UVA is the Ultraviolet light usually within 320 to 400 nanometers. That goes deep. UVA also crosses through glass, window glass, glass from your car. That's why it's important to wear sunscreen even indoors if you're working next to a window. It results in what we call "premature aging," unwanted brown spots, fine lines, wrinkles. Whereas UVB, it skims the surface of your skin. This one usually is the one that contributes to burning. Both of these also cause skin cancer. Like you just said earlier, one out of five Americans are going to get skin cancer in their lifetime, whether it's a basal cell, a squamous cell, or the worst kind of melanoma.

Brian Lehrer: What does SPF even stand for? We see the ratings on the sunscreen containers, 30 SPF, 50 SPF. You were talking about that range. What's SPF?

Dr. Idriss: That's a great question. SPF stands for Sun Protection Factor. It's a measure of how much solar energy is actually needed to produce a burn on protected skin versus unprotected skin. For example, let's say it takes you 10 minutes to turn red without any sunscreen on. If you get an SPF of 15 on your skin, it's going to take you 15 times that amount of time, so 150 minutes to turn red. It's giving you a good gauge to expand how long you have to be under the sun in order to get a sunburn.

Brian Lehrer: Do you need less sunscreen if you have darker complexion skin?

Dr. Idriss: No. That's actually a really good myth that people oftentimes believe, but it doesn't matter how dark you are. Most people, everybody, basically, needs the same amount of sunscreen, which is a quarter of a teaspoon for their face.

Brian Lehrer: I'm going to ask you an indoors question. Blue light exposure from our screens also refer to as high-energy visible or ATV light. Is that bad for the skin?

Dr. Idriss: That is also a really, really good question. 10 minutes is not enough, but it is a huge cause of concern. Most recently everyone's been saying devices, or cell phones, tablets all have blue light in our skin, but the current evidence has shown that the irradiation from our devices is not high enough to cause damage. We actually get blue light exposure from the sun. This is where the sun, when you go outside, if it's in very high doses or if it's in the day, can generate a lot of free radical damage and oxidative stress. Currently, I would say more research is still needed.

Brian Lehrer: Last question. Clothing. I've only learned recently that you might be wearing a hat, but that hat might not be of the right material to actually protect your head from the sun or the same with shirts or other things. Is that really true? We've got 30 seconds.

Dr. Idriss: Absolutely. I think when you're thinking of clothing, the tighter the better, the more colorful the material, the better, and the thicker the fabric, the better. Something like linen is very translucent and light, whereas something like a high knit cotton t-shirt that is in blue is probably going to be better to protect your skin.

Brian Lehrer: We will have to leave it there with Dr. Shereene Idriss, board-certified dermatologist. So much information. I could just visualize people taking notes out there as you were giving answer after answer. Thanks so much for coming back on the show.

Dr. Idriss: Thank you so much for having me. Have a great week.

Brian Lehrer: You too. That's it for the Brian Lehrer Show today. Thanks for listening everybody.

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