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Sun Exposure

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This page provides an overview of how the sun’s energy is needed for survival and how various types of ultraviolet radiation that can be dangerous to our skin.

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While some exposure to sunlight can be enjoyable and healthful, too much can be dangerous. Ultraviolet radiation (UV) comes naturally from the sun. UV is divided into three different categories based on wavelength. Wavelength is the distance between two successive peaks of a wave. UV wavelengths are measured in nanometers (nm) or one billionth of a meter. The shorter the wavelength the higher the energy.

Therefore, the UV radiation reaching Earth’s surface is largely composed of UVA with some UVB. Almost half the daytime total UV radiation is received between the hours of 10 a.m. an 4 p.m. Even on a cloudy day, you can get sunburned because of UV radiation.

Even on a cloudy day you can get sunburn from UV radiation.

One in five Americans develops skin cancer, and one person dies from this disease every hour. The incidence of melanoma, the most serious type of skin cancer, is increasing faster than most other forms of cancer. Children are of particular concern since most of the average person's lifetime sun exposure occurs before the age of 18. There are simple protective measures that you can take to limit exposure to UV rays.

Who is protecting you

U.S. Environmental Protection Agency (EPA)

EPA sponsors the SunWise program, which teaches the public how to protect themselves from overexposure to the sun. Through the use of classroom-based, school-based, and community-based components, SunWise seeks to develop sustained sun-safe behaviors in schoolchildren.

National Oceanic and Atmospheric Administration (NOAA)

EPA worked with the NOAA’s National Weather Service to develop the UV Index, which predicts the next day's ultraviolet radiation levels on a 1-11+ scale, helping people determine appropriate sun-protective behaviors.

World Health Organization (WHO)

The World Health Organization revised guidelines for reporting the UV Index. The United States and Canada both adopted these guidelines and applied them to their current UV Indexes.

U.S. National Institutes of Health (NIH)

The National Cancer Institute provides prevention, screening, and treatment information for skin cancer. Together with EPA and the Centers for Disease Control and Prevention, the NIH researches methods to protect against the sun’s harmful rays, and provides helpful information to the public.

U.S. Food and Drug Administration (FDA)

FDA establishes rules that govern the makers of sunscreens, particularly product labeling and advertising. FDA ensures that the Sun Protection Factor (SPF) for sunscreen is clearly written on its label, and that consumers clearly understand what SPF means.

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What you can do to protect yourself

Regardless of your exposure to UV rays, conduct a monthly skin self-exam looking for any abnormalities (like bumps or sores that don't heal) or moles that have changed size, color or shape.  Be sure to check all areas.  Have a friend or family member check your back. Visit your physician or a dermatologist to get annual exams.  If caught early, most cases of skin cancer can be cured.

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SunWise Program
March 30, 2012. U.S. Environmental Protection Agency
On this site, you can find materials that teach people how to protect themselves from overexposure to the sun.
UV Index
March 30, 2012. U.S. Environmental Protection Agency
On this page, you can learn about  the UV Index.
More WHO Member States unite in fight against skin cancer caused by excessive exposure to UV radiation 
March 30, 2012. World Health Organization exit EPA
This page is a press release from the World Health Organization. The press release shares the news of additional support for countries in using the Global Solar UV Index to educate citizens about the dangers of overexposure to ultraviolet radiation.
Skin Cancer
March 30, 2012. U.S. National Institutes of Health, National Cancer Institute
This page provides information about skin cancer treatment and prevention.
Ultra Violet Radiation Awareness
March 30, 2012. U.S. National Oceanic and Atmospheric Administration
You will find links to information about the UV Index and UV radiation on this page.
Global Solar UV Index:  A Practical Guide (PDF) (18pp, 429Kb [about pdf format]) exit EPA
Joint recommendation of the World Health Organization, World Meteorological Organization, United Nations Environment Programme, and Internal Commission on Non-Ionizing Radiation Protection [accessed on March 30, 2012]
This guide has details on Global Solar UV index issues, sun protection messages and educational concepts.

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