Answer to Question #11533 Submitted to "Ask the Experts"

Category: Lasers, Infrared, and Ultraviolet Radiation

The following question was answered by an expert in the appropriate field:

Q

I would like to know if there has been an increase over time in diseases related to ultraviolet (UV) radiation. Does the ozone layer depletion make people more susceptible to ultraviolet radiation? Are there other inventions like tanning beds that emit ultraviolet radiation that are dangerous to us?

A

The short answer to your questions is that one should limit one's exposure to UV light from the sun and limit one's use of tanning beds. UV light is a natural component of sunlight but can also be produced by tanning beds or other specialized light sources. The predominant health effect from exposure to UV light is the formation of skin cancers. These cancers can be of the types known as basal cell carcinomas, squamous cell carcinomas, and melanomas, the most dangerous of the three cancer types. UV light can also damage skin through drying, increasing skin aging, and forming wrinkles.

The US Centers for Disease Control and Prevention (CDC) has reported that the incidence of skin cancers from 2002 to 2011 has increased significantly in white males and females but remained constant in other races (Native Americans, Asian/Pacific Islanders, and Hispanics). The mortality of white men from skin cancer has also increased but there is no mortality data for white women. See the CDC website. The susceptibility to UV light's effects is related to biological processes such as sensitivity to sunlight or one's complexion.

One of ozone's functions in the Earth's atmosphere is to filter out and reduce the amounts of UV light reaching the Earth's surface. As the ozone is depleted, more UV penetrates and reaches the surface. This increase in ground-level UV (or UV from tanning beds) leads to the increase in the observed skin cancer trends previously mentioned. Therefore, the use of sun-blocking agents with a high sun protective factor (SPF) helps reduce the skin-damaging effects of UV light. In essence, the susceptibility does not change but the intensity of UV light does change.

UV light can be produced by artificial means including "bug zappers," welding activities, some fluorescent-type artificial lights, phototherapy units, and tanning beds. Among these, tanning beds are perhaps the most widely used. Both the CDC and the US Food and Drug Administration have expressed concern about the use of tanning beds, especially by those under the age of 18.

In summary, UV light-related diseases, especially skin cancers, have increased over time as ozone concentrations in the atmosphere have decreased. These increases in skin cancer also may be related to the increased use of tanning beds, especially by younger adults and people under 18 years of age.

Paul Charp, PhD

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