Clothing is the best protection against ultraviolet (UV) radiation from the sun, according to cancer experts. UV can damage the skin and cause skin cancer, dpa reported.
A light white T-shirt blocks all but a tenth of solar UV radiation, meaning it has an ultraviolet protection factor (UPF) of 10, pointed out the organizations German Cancer Aid and the Consortium Dermatological Prevention.
Dark, closely-woven cotton clothing has UPF factors exceeding 20. In other words, such clothing allows less than a twentieth of the UV radiation to reach the skin.
Special UV protective clothing - some textiles are marked as such - have UPF factors as high as 80. By comparison, a sunshade has a factor of 5, and trees between 5 and 15, depending on the density of their foliage.
As a safety precaution, sunscreen should always be applied to skin not covered by clothing. The sunscreen should have a sun protection factor (SPF) of at least 20, which guards the skin against both long-wave UV radiation (UVA) and medium-wave UV radiation (UVB).