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What is the “UV Index” and why should I care?

The Ultraviolet (UV) Index, developed by the National Weather Service (NWS) and the Environmental Protection Agency (EPA), is a forecast of the amount of ultraviolet radiation expected to reach the Earth’s surface when the sun is highest in the sky.  Meausured on a scale of 1-10, the higher the index, the faster UV radiation causes damage to the skin.  A UV index number of 0-2 is considered a minimal exposure level, 3-4 low, 5-6 moderate, 7-9 high, and 10+ very high.  The index depends on many factors including:  the elevation of the sun, the cloud cover, and the amount of ozone.  Anytime the index gets above 5, more aggressive protection from the sun is recommended.  The UV Index measures the two forms of UV light:  UVA and UVB.  UVA rays do not fluctuate throughout the day or year.   In other words, they are around from 6 am to 6 pm (a good rule of thumb is that if you can see outside without a flashlight, there are UVA rays hitting you), 365 days a year.  Since UVA penetrates window glass, they can hit the skin when sitting near the side window of a car (not the windshield, which blocks out all UV rays) or near a window at the office.  Worse yet, you can’t feel these rays as heat.  Because they penetrate so deeply in the skin, UVA rays are responsible for most of the accelerated skin aging such as:  wrinkles, brown spots, texture changes and uneven tone.  People who work or lay in the sun develop tough, leathery skin that may make them look much older.  Too much sun changes the texture of the skin and weakens the skin’s ability to snap back after stretching, causing sagging cheeks and deep wrinkles.  This is mainly due to collagen and elastin damage in the dermis of the skin.  UVA rays can also cause unsightly red, yellow, gray, or brown spots.  UVB rays, on the other hand, are most abundant from 11 am to 3 pm.  In fact, two-thirds of a given day’s UVB rays are within that window of time.  Depending on where you are in latitude, UVB rays peak in the summer months and are at much lower levels during the winter.  UVB rays cause most skin cancer and sunburns.  Clouds, water, sand, concrete and snow can all reflect both UVA and UVB rays.  So, what can you do to protect your skin from the sun and stop premature aging?  First, pay attention to the UV Index reports (available on the National Weather Service website).  The higher the number, the more diligent you should be.  Try to minimize sun exposure and outdoor activities from 11 am to 3 pm.  Applying a broad-spectrum sunscreen containing zinc oxide and titanium dioxide (for maximum UVA and UVB protection) on a daily basis is key to avoiding the long-term skin aging effects of the sun.  It also never hurts to wear a lip balm with sunscreen as well as UV blocking sunglasses when outdoors.

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