July 22, 2010
Beach Umbrellas Not As Helpful As You Think
In a new Spanish study, researchers are warning that taking shade under a beach umbrella may offer far less protection from harmful ultraviolet radiation from the sun than you might expect.
Beach umbrellas let as much as 34 percent of ultraviolet radiation penetrate through to the ground, the researchers, from the University of Valencia, found. Ultraviolet radiation is known to cause skin cancer and cataracts.
Umbrellas catch almost all of the direct light rays but not the diffused radiation that penetrates through from the sides, according to the research.
For the study, researchers placed an ultraviolet ray sensor on the base of a blue and white canvas umbrella with a radius of 12 inches and a height of about 5 feet.
"The umbrella intercepts the direct radiation that comes from the sun, but part of the diffused radiation, which makes up approximately 60 percent of the total, reaches the sensor from the sky not covered by the umbrella," said Jose Antonio Martinez-Lozano, one of the study's co-author.
In addition to umbrellas, doctors recommend people also use sun creams, hats and clothing when at the beach to help guard against ultraviolet radiation. People should also avoid direct sunlight when the sun is at its highest.
The research is published this week in the journal Photochemistry and Photobiology.
On the Net:
- FECYT - Spanish Foundation for Science and Technology
- Photochemistry and Photobiology
- University of Valencia