What are the different types of UV rays?

Jenny C. Hu, MD
The sun emits all kinds of rays: cosmetic rays, gamma rays, x-rays, ultraviolet rays, infrared rays, microwaves, short radio waves and long radio waves. The ultraviolet (UV) rays produce UV radiation, which has three main components: ultraviolet A (UVA), ultraviolet B (UVB) and ultraviolet C (UVC). Most UVC rays filter through the ozone layer and the atmosphere of the earth, so not much reaches the earth’s surface. UVB rays do reach the surface, although some of UVB radiation is filtered out. Considerable amounts of UVA radiation reach the earth’s surface.
There are two types of ultraviolet solar radiation -- A and B. Both types of rays may cause skin damage or possibly skin cancer. Sun protection factor (SPF) measures the protection that a sunscreen provides against ultraviolet B (UVB) but not ultraviolet A (UVA) rays, which penetrate more deeply into the skin, creating wrinkles. To protect your child against both types of rays, it is important to look for sunscreens that are labeled "broad spectrum," or check the ingredients for the four Food and Drug Administration (FDA)-approved UVA blockers: titanium dioxide, zinc oxide, avobenzone, or mexoryl. Use of these products will minimize your child's exposure to both UVA and UVB rays.


UVC is extremely dangerous, but fortunately it's absorbed by our atmosphere, so unless you're in the space station, it's of no concern.

UVB is the second most potent. It is responsible for sunburns (remember "B" for burns). It's also responsible for making vitamin D in your skin -- so it has both good and bad qualities. It's present during summer and on sunny days. Excess exposure to UVB leads to basal cell and perhaps melanoma skin cancers. 

UVA is the least potent, but most abundant. 95% of the UV light that reaches us is UVA. It does not increase your vitamin D levels. UVA penetrates clouds and car windows. We're exposed to it year round. It increase your risk for melanoma, squamous cell carcinoma and skin aging (wrinkles, brown and red spots). 

Sunlight is composed of two harmful types of radiation: ultraviolet A (UVA) and ultraviolet B (UVB) rays. Both types have been known to lead to skin cancer. Research has shown that UVA rays age the skin and may lead to age spots and wrinkles. They also suppress the immune system, which protects against infection and cancer. UVB rays cause the most immediate damage to the skin. They penetrate the first layer of skin (epidermis) and act on the cells that produce melanin, which can result in a darker skin, a painful sunburn, and even skin cancer.

Use a sunscreen and wear protective clothing to safeguard your skin from the sun’s harmful rays.

Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
The sun acts sort of like one of those machines that shoots out tennis balls. But the sun's tennis balls come in the form of ultraviolet rays that are torpedoed down to earth. The rays that are constantly being played into your court are the UVA rays and the UVB rays. Now, you have a choice: get pummeled by the rays, or block them so that they bounce off of you.

Even though UVB rays are stopped at the level of the skin, they can still cause burning and cancer of the skin, although they cause tanning as well. Meanwhile, UVA rays deeply penetrate the skin to cause burns, wrinkles, and skin cancer.

It could be worse. Luckily, the most dangerous UV rays—UVC rays—are blocked by the atmosphere (like tennis balls being hit into the net before they reach you), so they have little effect on you.

Picture of sunbather
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.