Only UVB and UVA rays ever reach the earth’s surface and therefore your skin.
UV Radiation and the Skin
UVA rays penetrate more deeply into your skin and are primarily responsible for photoaging and tanning, whereas UVB rays don’t penetrate as deeply, have higher energy, and are responsible for sunburns.
UVA versus UVB
An easy way to understand the difference between UVA and UVB is to relate UVA to “light” and UVB to “heat”. Look at the graph above. Notice that UVA is fairly constant throughout daylight hours, whereas UVB gathers intensity with the warmth of the sun, peaking at mid-day, and declines again.
Skin Cancer is More Common in the U.S. Than All Other Forms of Cancer Combined!
Skin Cancer
Your risk of getting skin cancer is directly tied to your UVA and UVB exposure. Not only are skin cancer rates on the rise, but skin cancer is more common than all other cancers combined in the U.S.
BCC and SCC
Basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma account for about 99% of all skin cancers.2 BCC and SCC are related to cumulative, long-term sun exposure, while BCC and melanomas are related to intense sun exposure that typically results in sunburn.
Melanomas
BCC and SCC are by far the most common skin cancers and if diagnosed early are easily treated and rarely become life threatening. Melanomas, however, can be deadly if not diagnosed and treated early, killing an estimated 8,510 people in the U.S. annually.3 In fact, just 5 sunburns doubles your risk of melanoma.4
About 90% of age-related changes in your skin are caused by UV radiation.5
While UVB rays are absorbed in the epidermis, UVA penetrates deep into the dermis and damages the collagen, elastin and other fibers that give skin its structure and a smooth, youthful appearance. UVA also reduces your skin’s ability to repair itself and eventually will result in wrinkles, dark spots and sagging leathery skin.
SunFly is also developing broadband (UVA/UVB) indicators for the Cosmetic industry to help daily sunscreen users apply and maintain broadband protection to their face, neck and hands.
1. American Cancer Society, “Key Statistics for Basal and Squamous Cell Skin Cancers,” August 11, 2026 (skin cancer); American Cancer Society, Cancer Facts & Figures 2026 (breast, lung, prostate and colorectal cancer).
2. American College of Mohs Surgery, “Skin Cancer Basics,” accessed October 16, 2026.
3. American Cancer Society, Cancer Facts & Figures 2026.
4. The Skin Cancer Foundation, “Skin Cancer Facts & Statistics,” March 2026.
5. The Skin Cancer Foundation, “Great Skin Is Made in the Shade,” November 4, 2021.