Umbrellas block most UV radiation

Handheld umbrellas can block between 77 and 99 percent of UV radiation, according to results of a recent study.

Researchers collected 23 umbrellas from attendees at the Emory University Grand Rounds in Atlanta. The investigators used a meter to detect UVA and UVB radiation to measure UV radiation in microwatts per square centimeter, according to the research letter. They measured UV radiation without an umbrella at the start, middle and end of the study. Researchers also measured radiation in two standard positions with the umbrellas, and then measured UV radiation inside a nearby building in a windowless room after the study.

UV radiation readings taken from 1 cm under the umbrella fabric ranged from 26 to 1714 µW/cm². Measurements taken 1 cm from the researcher’s nose while holding the umbrella overhead ranged from 67 to 1256 µW/cm².

“The correlation between the repeated set of measurements was very high (r=0.995, P<0.001),” researchers noted. “The umbrellas blocked between 77 percent and 99 percent of UVR.”

The research letter was published online March 20 in JAMA Dermatology.