Sunscreen
The most effective sunscreens protect against both UVB (ultraviolet radiation with wavelength between 290 and 320 nanometres), which can cause sunburn, and UVA (between 320 and 400 nanometres), which damages the skin with more long-term effects, such as premature skin aging. Most sunscreens work by containing either a petrochemical compound that absorbs ultraviolet light (such as oxybenzone) or minerals that reflects light (such as titanium dioxide, zinc oxide), or a combination of both.