| SUN FACTS Ultraviolet (UV) rays are the sun's invisible "burning" rays � the ones that cause sunburns, and in some cases, skin cancer. There are three types of ultraviolet rays: UV-A These rays of the sun maintain a relatively constant intensity throughout the year and also penetrate more deeply into the skin's layers than UV-B rays. These rays contribute to premature aging and wrinkling of the skin, to sunburn, and even to skin cancer. UV-B These rays, which are stronger than UV-A, are more intense in summer months, at higher altitudes, and closer to the equator. UV-B is the most common cause of sunburning, can contribute to the premature aging of the skin, and can cause cataracts � a permanent clouding of the eye which greatly reduces vision. The UV-B exposure we get over the course of our life can even cause skin cancer and alter your immune system. UV-C These rays, although the strongest and most dangerous, are normally filtered by the ozone layer and do not reach the Earth. How much UV reaches me? The amount of UV you are exposed to changes with the time of day, seasons, weather conditions, and where you happen to be. The more intense the sun, the greater your exposure to UV. The amount of UV that will filter down to the Earth depends on the following: Time of Day: UV is greatest when the sun is highest in the sky � generally midday, between 10 AM and 3 PM � and less in the early morning and late afternoon. A good rule of thumb is "If your shadow is shorter than you are, you should take extra precautions in the sun." Season: While UV exposure is the greatest in the Summer (May-August), it is important to remember that UV reaches the Earth every day, and you should remember to take the appropriate precautions in the sun all year round. Altitude: The air is cleaner and thinner at higher altitudes; therefore, UV exposure is greater in the mountains than in the valleys. Where You Live: UV is strongest at the equator and gets weaker as you move towards the Earth's poles. Remember to take extra precautions if you travel to tropical locations! Length of Time Spent in the Sun: The longer you are out in the sun, the more UV you receive. Many of us forget to include time spent outside doing daily activities such as walking a dog, getting the mail, or walking to a train or bus stop as time spent in the sun. However, much of the UV exposure we get is from these types of activities. Protecting your skin during the first 18 years of life can reduce the risk of some types of skin cancer by up to 78%. You can get a sunburn even on a cloudy day! Up to 80% of the sun's rays can penetrate light clouds, mist, and fog. Experts warn that one severe sunburn during the first 15 years of life can double the risk of skin cancer. Cataracts, once thought to be an inevitable part of aging, are also associated with UV exposure. Snow reflects the sun like a mirror. Fresh snow reflects back about 85% of the sun's rays. You can get sunburned when you are in the water! Water reflects an additional 5% of the sun's rays back on you. Even dry surfaces reflect the sun's rays! Concrete reflects 10% to 12% of the sun's rays. |
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