When we are outdoors, we put on our sunglasses and apply sunscreen or sunblock lotions to protect us from harmful ultraviolet light that penetrates the Earth's atmosphere. There are two types of ultraviolet light, UVa (315-400 nanometers) and UVb (290-315 nm). http://jchemed.chem.wisc.edu/Journal/Issues/2001/Dec/abs1678.html Without the UV protection offered by sunscreen products, our skin can be damaged by UV-B light, causing skin cancer ( melanomas), wrinkles and other skin disorders. http://www.bucknell.edu/x7840.xml
Sunglasses are also important for the protection of your eyes because excessive exposure to UV-B rays causes a sunburn of the cornea is called ultraviolet keratitis. Damage to the cornea results in pain and decreased vision, and the condition usually resolves within a couple of days. Other sources of damaging ultraviolet light include operations were UV light are used, such as in libraries for document viewing, germicidal lamps and laboratories where gels are viewed using UV light. Significant sources also include arc welding and unshielded mercury lamps. http://web.princeton.edu/sites/ehs/healthsafetyguide/E4.htm
On this Mahalo page, we discuss some of the means of preventing damage, the types of damage that can occur, and various facts that are related to UV Protection.
UVa and UVb Protection with Sunscreens
Sunscreens contain substances that offer ultraviolet light protection in two ways: compounds that absorb ultraviolet light and particulates that reflect and scatter ultraviolet light. These two components thereby limit the amount of ultraviolet light your body actually absorbs. As the amount of UV light that your body absorbs increases, the probability that skin damage increases. People with different levels of melanin in their skin will require different levels of sunscreen protection. Sunscreen ratings (SPF) of 15 and 30 correspond to blocking 93% and 97% of the UV-A light, respectively. http://www.chemistrydaily.com/chemistry/Sunscreen Because the SPF rating is not based on the ability of the lotion to block the most harmful UV-B rays, it is important to choose products that have sun blocking agents as well: zinc oxide, titanium oxide, oxybenzone and/or azobenzone.
UV Daily Index
The UV Daily index is a service provided by the United States National Weather Service and the Environmental Protection agency. The reports provide information on days when the UV radiation exposure is moderate to high. http://www.cpc.noaa.gov/products/stratosphere/uv_index/uv_current.shtml
Protection from UV Light May Reduce Wrinkles
Wrinkles are a breakdown of the dermal layer of the skin. When it breaks down, there is less elasticity and support for the overlaying layer of the skin, the epidermis. Photo-aging is something that one can be reduced by reducing exposure to damaging UV light. Protection measures are most important, such as sunblocks, wide-brimmed hats, and protective clothing. There are some products that help rebuild the tissue support. These are known as retinoids, or Vitamin A, derivatives.
References
Fast Facts
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'''Health Recommendation'''
Everyone should have regular checks for skin abnormalities, using the ABCD diagnostic method, even when you regularly use sunscreens
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'''How the Earth's Atmosphere Protects Us'''
Ozone in the ozone layer
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'''What We Can Do to Protect Ourselves'''
Use suncreen lotions with sunblocking agents, UV-blocking sunglasses, hats (to protect the ears), and protective clothing.
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'''Protective lotions'''
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'''Sunglasses recommendations'''
Choose sunglasses that say 99-100 percent UVA and UVB protection, or "UV 400" or "meets ANSI UV requirements." The wraparound style or sunglasses with side panels offer the best protection of your eyes. On the average pair of sunglasses, the protection level is compromised because sunlight can easily enter the eye from the sides or tops of the frames. The sun is at its most dangerous between the hours of 10am and 4pm. If possible, try to avoid being outdoors during those times.
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'''Hours of the Most Harmful Rays'''
10 am to 4 pm
