Facts About Ultraviolet Radiation

• Our natural source includes:
  • The sun
• Some artificial sources include:
  • Tanning beds
  • Mercury vapor lighting (often found in stadiums and school gyms)
  • Some halogen, fluorescent, and incandescent lights
  • Some types of lasers

UV radiation is classified into one of three primary groups: ultraviolet A (UVA), ultraviolet B, (UVB) and ultraviolet C (UVC). This grouping is based on the measure of their wavelength, which is measured in nanometers (nm= 0.000000001 meters or 1×10^-9 meters).

All UVC and most UVB radiation is absorbed by the earth’s ozone layer, so nearly all of the ultraviolet radiation received on Earth is UVA. Even though UVA radiation is weaker energy than UVB, it penetrates deeper into the skin and is more constant throughout the year. Because UVC radiation is absorbed by the earth’s ozone layer, it does not pose as much of a risk. UVC produced by germicidal UV lights, however, can be harmful from human exposure.

Benefits

• Beneficial effects of UV radiation include the production of vitamin D, a vitamin essential to human health. Vitamin D helps the body to absorb calcium and phosphorus from food and assists in bone development. The World Health Organization (WHO) recommends 5 to 15 minutes of sun exposure 2 to 3 times a week.
• Artificial forms of UV radiation used with some topical medications that increase UV sensitivity are used to treat patients with certain diseases who have not responded to other therapies. Artificial forms of UV radiation include lasers, lamps, or a combination of these devices. A trained healthcare professional uses a procedure called phototherapy to treat the following health conditions:
  • Rickets
  • Psoriasis
  • Eczema
  • Vitiligo
  • Lupus

Risks

• Sunburn is a sign of short-term overexposure.
• Premature aging and skin cancer are side effects of long-term UV exposure.
• Some oral and topical medicines, such as antibiotics, birth control pills, and benzoyl peroxide products, as well as some cosmetics, may increase skin and eye sensitivity to UV in all skin types.
• UV exposure increases the risk of potentially blinding eye diseases, if eye protection is not used.
• Overexposure to UV radiation can lead to serious health issues, including cancer. Skin cancer is the most common cancer in the United States.

The two most common types of skin cancer are basal cell cancer and squamous cell cancer. Typically, they usually form on the head, face, neck, hands, and arms because these body parts are the most exposed to UV radiation. Most cases of melanoma, the deadliest kind of skin cancer, are caused by exposure to UV radiation.

Anyone can get skin cancer, but is more common in people who

• Spend a lot of time in the sun or have been sunburned
• Have light-color skin, hair and eyes
• Have a family member with skin cancer
• Are over age 50

Changes in your skin are the most common signs of skin cancer. Learn more about the symptoms of skin cancer.

Keeping yourself and others protected from UV radiation is important year round, not just at the beach or during the summer months.

Protect yourself from UV radiation

• Stay in the shade, especially during midday hours.
• Wear clothes that cover your arms and legs.
• Wear a hat with a wide brim to shade your face, head, ears, and neck.
• Wear sunglasses that wrap around and block both UVA and UVB rays.
• Use sunscreen with sun protection factor (SPF) 15 or higher, and both UVA and UVB protection.

Certain types of glass and plastics can be used to block UV light, especially UVC.

The UV Index scale helps us understand how harmful UV radiation can be on a given day. This useful tool forecasts the strength of the sun's harmful rays. Remember, the higher the number, the greater chance of overexposure leading to health concerns.