Sunscreen works by combining organic and inorganic active ingredients.
Inorganic ingredients like zinc oxide or titanium oxide reflect
or scatter ultraviolet (UV) radiation. Organic ingredients like
octyl methoxycinnamate (OMC) or oxybenzone absorb UV radiation,
dissipating it as heat. Some sunscreens protect us from the two
types of damaging UV radiation: UV-A and UV-B. Both UV-A and UV-B
cause sunburns and damaging effects such as skin cancer.
Ultraviolet radiation is broken into three types of wavelengths:
- UV-A: This is the longest wavelength and is not absorbed by
the ozone. It penetrates the skin deeper than UV-B.
- UV-B: Responsible for sunburns. It is partially blocked by the
- UV-C: This is totally absorbed by the earth's atmosphere; we
encounter it only from artificial radiation sources.
purchasing sunscreen, the Sun Protection Factor or SPF measures
how effectively the sunscreen formula limits skin exposure to UV-B
rays that burn the skin. The higher the SPF the more protection
the sunscreen will provide against UV-B rays. SPF does not measure
UV-A. If you are looking for UV-A protection, the experts recommend
that you purchase a product that has broad-spectrum protection.
How to Select, Apply, and Use it Correctly - The
Centers for Disease Control and Prevention provides
a brief list
of sunscreen recommendations.
Academy of Dermatology
- The Sunscreen FAQS
website gives information about choosing sunscreen, applying
sunscreen, treating sunburns and other questions relating
to protecting your skin from the sun.
Aims to Upgrade Sunscreen Labeling -
FDA wants the labeling on your sunscreen to tell you more
about protection against the sun's harmful rays.
Sun Safety - A guide to the UV index and Sun-Safe
Behavior. This website from the EPA provides information
about UV, health risks of sun exposure, and how to protect
yourself from the damaging effects of the sun.
Prediction Center: Current UV Index Forecast - This
website provides the UV index at high noon for the United
Radiation: NASA - NASA Advanced Supercomputing Division
educational resource on ultraviolet radiation contains an
introduction to ultraviolet radiation and the health effects
of UV-B radiation. References are also cited at the end
of the article.
Marc. Sunscreens: active ingredients prevent skin damage.
Chemical & engineering news, v. 80, June 24,
development, evaluation, and regulatory aspects. Edited
by Nicholas J. Lowe, Nadim A. Shaath, and Madhu A Pathak.
2nd ed. New York, Marcel Dekker, c1997. 792 p.
- Sunscreen. In How products are made: an illustrated guide to product manufacturing. Edited by Jacqueline L. Longe. v.2. Detroit, Gale Research, c1996. p. 429-433.
radiation and ozone depletion: effects on humans, animals,
plants, microorganisms, and materials. Edited by
Manfred Tevini. Boca Raton, FL, Lewis Publishers, c1993.
States. Adequacy of protection from sunglasses and sunscreens:
hearing before the Ad Hoc Subcommittee on Consumer and
Environmental Issues of the Committee on Governmental Affairs,
United States Senate, One Hundred Second Congress, Second
session, June 5, 1992. Washington, U.S. G.P.O., 1993.
more print resources...
Search on "sunscreen,"
"uv" and "ultraviolet"
in the Library of Congress Online
[Father applying sunscreen to his daughter]. From the Centers for Disease Control and Prevention website.
Society leaders display 200 years of beach attire at Cape May Sun Tan Cabana Club. Underwood and Underwood, 1931. Prints and Photographs Division, Library of Congress.
An adult applying sun screen on a child. From the Centers for Disease Control and Prevention website.