Kate's Corner: How does sunscreen work?

Published: May. 31, 2017 at 5:09 PM EDT
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Summer break is just beginning for a lot of the kids across the area. This means more and more time outside whether it be at the pool or the playground.

All this time outdoors means that our skin is hit by invisible rays that can darken or even burn your skin. These rays are known as ultraviolet radiation or UV rays from the sun. Ultraviolet radiation is broken down into three types of wavelengths. UV-A penetrates deeply into the skin and is linked with skin cancer and premature skin aging. UV-B is associated with tanning or burning our skin. Finally, UV-C is completely absorbed by the earth's atmosphere so it doesn't affect us.

We can protect our skin from these damages by wearing sunscreen. Now sunscreen combines organic and inorganic chemicals to filter the light from the. If you want to completely block the light, sunblock is what you need. This will reflect or scatter the light so that none reaches your skin.

You may pick up your bottle of sunscreen and see a number on it. What is that? That is the Sun Protection Factor of the SPF. This tells you how well the sunscreen protects you from UV-B rays. Say you grab a SPF 15 bottle. That sunscreen will protect your skin 15 times longer than usual. So if you usually burn after 10 minutes in the sun, a SPF 15 sunscreen will protect your skin for 150 minutes.

Now your skin has a natural SPF determined by how darkly your skin is pigmented. No matter how dark your skin is, you can still damage it.

For the safest time in the sun, it is recommended to use a broad-spectrum sunscreen that protects against UV-A and B rays and to reapply every 2 hours.

Many people don't want to wear sunscreen because then they won't get tan. That's a myth. Sunscreen filters the sun but don't block it completely.

It all depends on the SPF strength. According to the Skin Cancer Foundation, SPF 15 blocks 93% of UV-B radiation and SPF 30 blocks 97%. So you're still getting tan just at a slower and safer rate.