As most of us are aware, the earth’s ozone layer protects all life on earth from excessive exposure to ultraviolet radiation (UV) from the sun.
Did you also know there are three types of UV rays? They are UVA, UVB and UVC. The “A”, “B” and “C” following UV are indicators of the ultraviolet wavelength size with “A” being long, “B” is medium and “C” is short.
Out of these, only UVA and UVB types are harmful to our skin, this is because the third type, the UVC radiation, does not penetrate the atmosphere’s ozone layer and does not reach Earth.
- Most of us are exposed to large amounts of UVA throughout our lifetime. UVA rays account for up to 95 percent of the UV radiation reaching the Earth’s surface. Although they are less intense than UVB, UVA rays are 30 to 50 times more prevalent. They are present with relatively equal intensity during all daylight hours throughout the year, and can penetrate clouds and glass.
- UVA, which penetrates the skin more deeply than UVB, has long been known to play a major part in skin aging and wrinkling, and more recently has been found to contributes to and may even initiate the development of skin cancers.
- UVA is the dominant tanning ray, and we now know that tanning, whether outdoors or in a salon, causes cumulative damage over time. A tan results from injury to the skin’s DNA; the skin darkens in an imperfect attempt to prevent further DNA damage. These imperfections, or mutations, can lead to skin cancer.
- Tanning booths primarily emit UVA. The high-pressure sunlamps used in tanning salons emit doses of UVA as much as 12 times that of the sun.
- UVB, the chief cause of skin reddening and sunburn, tends to damage the skin’s more superficial epidermal layers.
- It plays a key role in the development of skin cancer and a contributory role in tanning and wrinkles.
- Its intensity varies by season, location, and time of day. The most significant amount of UVB hits North America between 10 AM and 4 PM from April to October.
- However, UVB rays can burn and damage your skin year-round, especially at high altitudes and on reflective surfaces such as snow or ice, which bounce back up to 80 percent of the rays so that they hit the skin twice.
- UVB rays do not significantly penetrate glass.
The UV index indicates the intensity of the sun’s UVB rays. There are five categories – low, moderate, high, very high and extreme. You should always take precautions when you go out under the sun and the UV index is equal or higher then 3. The index is often included with weather reports and is a good tool to help choose proper sun protection.
Since both UVA and UVB are harmful, you need protection from both kinds of rays. If you can’t cover up, use a sunscreen containing a Sun Protection Factor (SPF) of at least 15, verify it has both UVA and UVB protection, re-apply every two hours and after sweating or swimming.
Disclaimer - The material provided on this site is designed for information and educational purposes only. The materials are not intended to be a self diagnostic and/or self treatment tool. I encourage you to use this information as a tool for discussing your condition and/or concerns with your health practitioner.