Know Your Solar Rays: UvA, UvB and UvC
Our world is illuminated and energized from the light released by the sun streaming earthward in the form of waves. Those light waves are similar to the movement of water in the ocean, except solar waves, originating 90 million miles away and taking about 8 minutes to get to Earth, take on distinct wavelengths. Three of those wavelengths, known as UvA, UvB and UvC are invisible and have been associated with the damaging, and sometimes deadly effects conventionally attributed to solar radiation.
UvC, the shortest of the three wavelengths, is associated with skin cancers and is considered to be the most dangerous, but (theoretically anyway) the earth’s atmosphere offers protection.
The longest wavelength, UvA, are linked to harmful effects in the lower levels of the skin that can show up as wrinkles, fine lines and other indicators of photoaging. Solar rays of UvA length can penetrate through glass windows and remain constant all year long, making them a troublesome source of skin damage January through December. UvA rays can even penetrate through glass windows, which can be relevant for folks who sit near windows when driving, traveling or just hanging out at home.
The third solar wavelength, UvB, is a medium sized wave (longer than UvC and shorter than UvA) and is the cause of sunburning, skin redness and cataracts. On a positive note UvB is responsible for converting cholesterol, found in considerable quantities in skin, into Vitamin D.
Most chemical sun screening ingredients block UvB, a couple block UvA, but the only way to get truly broad-spectrum sun protection from all rays is to use zinc oxide and titanium dioxide which act to reflect ALL the sun rays, including UvA, B and C, refracting them in their crystalline structure like a reflection in a mirror. As far as OVERALL sun safety goes, don’t be misled by SPF ratings, which are only indicators of UvB protection and provide no information about shielding from UvA or C damage. SPF is merely a measurement how well a product can help prevent sunburns and not a reliable indicator of protection from wrinkles, skin aging or cancer.
