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USA Today: How to Avoid a Sunburn,
UV Indices Explained
Ultraviolet radiation, commonly referred to as UV radiation, is emitted constantly from the sun. It has an overall wavelength range between 100 and 400 nanometers (nm) which is divided into three sections: UVA (315-400 nm), UVB (280-215 nm), and UVC (100-180 nm). The earths surrounding atmosphere absorbs approximately all UVC radiation and about 90% of UVB radiation. The UV radiation that reaches the earths surface is composed of mostly UVA radiation with small measurements of UVB.
Over the years, extensive research done by scientists and medical experts has shown the detrimental effects of ultraviolet radiation (UV) on the skin. This harmful light can instigate side effects varying from mild sunburns to deadly skin cancer. In order to expand the publics knowledge of ultraviolet radiation as a potential health hazard, the Environmental Protection Agency and National Weather Service developed the UV Index. This index is published daily and consists of an estimation of the UV radiations maximum risk factor for the following day.
When reading the UV Index it is important to keep the following factors in mind:
- Exposure categories are conservative and based off the effects of UV radiation
on fair skin.
- The index contains a description of the effect of cloud cover.
- The UV radiation risk may fluctuate depending on the distance from the UV
- The UV intensity in the continental United States is reduced to about half its
usual intensity approximately 3 hours before and 3 hours after noon.
The following is a table depicting the UV Index and its categories according to rate of exposure. This table also includes possible solutions developed by the Environmental Protection Agency to aide in reducing UVA and UVB exposure:
General Recommended Action (All Skin Types)
||Apply SPF 15+ sunscreen
||Apply SPF 15+ sunscreen and wear protective clothing including a hat
||Apply SPF 15+ sunscreen, wear protective clothing including a hat and protective sunglasses
||Apply SPF 15+ sunscreen, wear protective clothing including a hat and protective sunglasses, avoid the sun between 10 am and 4 pm.
UVA/UVB radiation levels are at their highest on cloudless days, but can still maintain dangerous levels despite cloud coverage due to the scattering of radiation by water molecules and other atmospheric particles. UVA/UVB radiation also has the ability to penetrate through glass and most fabrics. It then penetrates the epidermis and dermis (outer and inner layers of skin) and increases the chance of sunburn and skin-cancer. This is one of the many reasons why it is a crucial to the healthy maintenance of skin to maintain an awareness of the dangers of UV radiation as well as knowledge of how to prevent the serious damage it can cause.
Aside from the general recommended action provided in the above table, here are a few additional suggestions to protect your skin from UVA/UVB radiation damage:
- Avoid sun tanning as well as tanning beds-UV radiation from tanning beds can cause
premature wrinkles as well as skin cancer.
- Be cautious of water, snow, and sand-They reflect the damaging light from the sun which can increase chances of sunburn.
- Some experts suggest safely consume vitamin D - Instead of sunbathing, eat vitamin supplements and vitamin
D fortified foods.
- Watch the UV Index - It provides information that can help daily activities be planned in
a way to prevent overexposure to UV radiation.