Advantages of Clothing for Sun ProtectionThere are many advantages of clothing over sunscreen for sun protection. That's not to say you should skip the sunscreen -- you shouldn't. However, here are some advantages of clothing as a form of sun protection:
- Clothing protects against UVA and UVB radiation, whereas most sunscreens don't provide enough UVA protection.
- Clothing provides uniform protection, while sunscreen is typically not applied uniformly.
- Clothing provides consistent protection from the moment you put it on, while sunscreen has to be applied 30 minutes before going out and reapplied every 2 hours.
- Given that it is reusable, and that you may not have to even go out and buy it for this purpose, clothing is not as expensive as sunscreen. Often, the clothes you have in your closet work well for sun protection.
UPFThe UPF of clothing is similar to the SPF of sunscreen. UPF stands for UV protective factor and it describes how much UV radiation a piece of fabric or clothing will block. The UPF standard was developed in Australia in 1996 and is accepted in Europe. In the US there are 3 different guidelines for determining UPF in clothing.
Factors That Influence UPFCertain fabrics naturally have a higher UPF than others. Polyester and wool block the most UV radiation, but they are uncomfortable to wear in summer. Polyester can be added to other fabrics to increase their UPF. The tightness of the weave or knit in fabrics plays a large role in determining UPF. Fabrics that shrink after washing them like cotton, rayon, and flax have a higher UPF after they are washed. Most fabrics, though, have a lower UPF when they are wet. Lighter colored fabrics have a lower UPF than darker fabrics.
Chemical treatment of fabric with optical brighteners and UV absorbers significantly increases the UPF. Optical brighteners can be found in many regular laundry detergents. Tinosorb FD is a UV absorber marketed as Sun Guard and it is added to clothes in the wash. Several studies have shown Tinosorb can increase the UPF of a t-shirt by 400%.
Finding Sun Protection ClothingThe Skin Cancer Foundation gives a Seal of Recommendation to clothing that meets their strict requirements for aiding in the prevention of sun-induced damage to the skin. Those recommendations can be found here.
Hatch, KL. "American standards for UV-protective textiles." Recent Results of Cancer Research. 160(2002): 42-47.
Wang, Steven, et. al. "Photoprotection: A review of the current and future technologies." Dermatological Therapy. (23)2010:31-47.