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UV Radiation: Why Do We Wear Sunscreen?

Columbia, MO

You’re going outside to play in the bright, warm sunlight, but as soon as your fingertips touch the door handle, you hear someone yell your name. It’s your parents. As you begrudgingly go to see what your parents want, they simply say, “Put on sunscreen!” But why? Why do you need to wear sunscreen? Why do you have to spend an additional 5 minutes smearing some sunscreen across your limbs instead of just going outside? Well, it’s to protect you and your skin from UV radiation that the sun releases.

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This is an image showing the electromagnetic spectrum.

First, what is UV? On the electromagnetic spectrum, from lowest wavelength to highest, there are the colors purple (violet), blue, green, yellow, orange, and then red. But those lights are from the visible light spectrum, and as the name implies, these are the colors we can see. So, what about the ones we cannot see? That’s where ultraviolet light (UV) comes in. UV’s wavelength is much shorter than that of visible light; purple has a wavelength of 400 nm and that value increases as you get closer to red, but UV has a wavelength from around 100 nm to 400 nm. And while we can’t see it, other animals and insects like bumblebees can.

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This image depicts the three different categories of UV radiation: UVA, UVB, and UVC.

But ultraviolet radiation gets much more complicated than that. UV radiation is divided into three categories: UV-A, UV-B, and UV-C. UV-A rays have the least amount of energy yet can still cause damage to the human body by indirectly affecting skin cells’ DNA as UV-A radiation causes oxidation of DNA bases, leading to mutations. This type of UV radiation often causes wrinkles and can potentially cause skin cancer. Next are UV-B rays which have more energy than UV-A rays but less energy than UV-C rays. Compared to UV-A which only indirectly damages your cells, UV-B rays directly damage skin cells’ DNA and are the main causes of skin cancer and sunburns. Finally, UV-C rays have the most energy and are the most harmful of the three, though they are typically absorbed by the atmosphere and thus don’t typically harm people.

Now that we know the harmful effects of UV radiation on the human body and health, we must learn how to mitigate the chances of getting skin cancer.

One way is by simply avoiding the sunlight or anything that uses UV radiation like a tanning bed, because if you want to mitigate your chances of getting skin cancer, a surefire way is by decreasing your exposure to UV rays. Additionally, when you go outside into the direct sunlight, wear a hat, sunglasses, clothing that covers your skin, and sunscreen. While they cannot block all UV rays, they can help prevent most of them from reaching you and are still beneficial for your health. Furthermore, sunscreens with SPFs of 30 or higher and protection against UV-A and UV-B rays are highly recommended. Last but not least, you can always take a peek at the UV Index on the Environmental Protection Agency’s website to see the strength of UV light rays near where you live. That way, you can avoid going out when the UV light rays are at their strongest.

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An image of sunscreen

Now that you know the risks and effects of UV radiation and how to protect yourself from them, you know why your parents always force you to wear sunscreen when you go out. So, the next time you go out, be sure to wear some sunscreen!


Works Cited:

“Does UV Radiation Cause Cancer?” Does UV Radiation Cause Cancer? | American Cancer Society, Accessed 8 Sept. 2023.

Gillespie, Claire. “What Are the Uses of Ultraviolet Light?” Sciencing, 2 Mar. 2019, Accessed 8 Sept. 2023.

“Is a Tanning Bed Safer than Sunlight? - Harvard Health Publications.” Harvard Health, 1 Sept. 2009, Accessed 13 Sept. 2023.

Subramanian, Dr. Supriya. “The Mechanism of DNA Damage by UV Radiation.” News, 26 Feb. 2019,

“Ultraviolet Waves.” NASA, NASA, Accessed 8

Sept. 2023.

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