By Mary Poffenroth
Many people know that sunscreen is important to prevent things like sunburn and cancer from UV radiation. But there are many different types of sunscreens, so how do they work, and how effective are they? The Sun emits three types of UV rays: UV A, UV B, and UV C. Ultraviolet light has shorter wavelengths than visible lights, which is what causes all of the bad effects like cancer, DNA damage, and sunburn. UV C has wavelengths so short that it is reflected by the atmosphere, but UV B can impact the skin, and UV A can go even deeper to blood and organs. Sunscreen prevents these effects by either physically blocking the UV rays or utilizing carbon-based chemicals to absorb the radiation. There are three factors to consider when choosing a sunscreen: application method, SPF, and active ingredients. Spray bottles go on easily when wet, but most people do not apply enough and the aerosol can be bad for health. SPF stands for sun protection factor, which is a nonlinear scale of the amount of UV B radiation needed to cause sunburn. 15 is the minimum recommended, but 30 and above is better. For chemicals, zinc and titanium oxide-based is usually less irritating to the skin. This is also better for the environment because carbon-based chemicals have been proven to be harmful to ocean life.
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