The Sun and Your Skin

Yes, it's true. Skin cancer rates are expected to double in the next 10 years, due to increased UVB radiation from a thinning ozone layer. According to experts at Columbia University and The World Health Organization, UVB is on the rise.

Get a primer on UV radiation from this lecture by Columbia University professor Peter deMenocal of the Lamon-Doherty Earth Observatory. The health risks associated with ozone depletion are principally due to increased ultraviolet B radiation (UV-B)resulting in increased damage to the eyes, the immune system and the skin. As sunlight passes through the atmosphere, all UV-C and approximately 90% of UV-B radiation are absorbed by O2, ozone, as well as water vapor, oxygen and carbon dioxide. UV-A radiation is less affected by the atmosphere. Therefore, the UV radiation reaching the Earth's surface is largely composed of UVA with a small UVB component. The region of concern for biological effects is the ultraviolet-B (UV-B) range, which has been dramatically increasing due a reduction of UVB-asborbing ozone.

Though concerns for human health are great, far graver are the potential impacts on the ocean. UVB kills phytoplankton, and phytoplankton is largely responsible for absorbing our CO2 emissions. A hypothetical loss of 10% of the marine phytoplankton would reduce the oceanic annual uptake of carbon dioxide by about 5 billion tons.

What causes ozone depletion?

Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4 percent per decade in the total amount of ozone in Earth's stratosphere since around 1980; and a much larger, but seasonal, decrease in stratospheric ozone over Earth's polar regions during the same period. The latter phenomenon is commonly referred to as the ozone hole.

The detailed mechanism by which the polar ozone holes form is different from that for the mid-latitude thinning, but the most important process in both trends is catalytic destruction of ozone by atomic chlorine and bromine. The main source of these halogen atoms in the stratosphere is chlorofluorocarbon (CFC) compounds, commonly called freons, and of bromofluorocarbon compounds known as halons. These compounds are transported into the stratosphere after being emitted at the surface. Both ozone depletion mechanisms strengthen as emissions of CFCs and halons increase.

So How do you stay protected?

• Get a good pair of sunglasses - your eyes are very susceptible to UVB radiation.

• Wear a hat -- the shade from your hat will keep "high noon" sun from striking your eyes and face

• Wear Sunscreen -- check out the Suncare options in EVO's Body section

• Try not to be out between noon and 2 -- that's when the sun is the hottest

• If you get burned slather on the Aloe Vera -- it will help your skin recover

• Don't use aerosol cans! They contain the cholorofluorocarbons that are the source of our ozone problem