Sunblock chemistry and you
Out here in
the Black Rock Desert, sunblock is not just a good idea, it's essential for
your survival. However, you should note that not all sunblocks will protect you
the same way, even if the SPF ratings are equal. Most over-the-counter products
offer basic protection from only one type of ultraviolet radiation, known as
UVB. For more complete protection, you should be using a sunblock that protects
against both UVB and UVA, a second type of ultraviolet radiation.
UVA is the
spectrum of sunlight that causes superficial sunburn. UVB is a longer spectrum
of light that penetrates more deeply into the skin. It's believed that UVB may
cause skin cancer, and its penetration builds over time. Check the label of
your sunblock¸the compound avobenzone offers the fullest protection against UVA
rays, and can be found in some Shade˙, Coppertone˙, and Water Babies˙ products.
For the most complete protection though, your sunblock should contain zinc
oxide or titanium dioxide¸both of which act as a physical block¸along with
additional active ingredients. And be warned: sunblocks that are labeled as
"broad-spectrum" or "UVA/UVB" are less protective, since
they contain oxybenzone or some other ingredient that blocks only a portion of
the UVA spectrum. Also, don't forget¸the SPF rating on sunblock only pertains
to UVB rays. So grease up liberally and don't get burned!