April 17, 1998

Disco duds defy the sun

Maybe John Travolta had it right with his disco clothes. One hundred per cent polyester could be the way to go.

Spring has officially arrived and summer is on its way. Soon the sun will be shining brightly and everyone will be wearing their new spring and summer fashions. But how to choose the new look? Should you go with what's popular in Milan? What you can afford?

A better choice might be based on the research of Dr. Nancy Kerr, acting chair, human ecology and Linda Capjack, assistant professor, who are investigating the effectiveness of clothing as protection against harmful ultraviolet (UV) rays.

Sunscreen is the most popular choice to protect from UV rays and possible skin cancer. The drawback is that you have to reapply it every few hours and it is not advisable to use sunscreen on young children. "Especially young children under two -- you probably shouldn't put sunscreen on them," says Capjack. The best thing to do for young children is to make sure they are covered with protective clothing. Children and parents are two groups Kerr and Capjack are hoping to target with the results of their research.

Capjack says, "Young people, adolescents, receive three times the exposure of a normal adult and yet don't cover up..All children are at quite a vulnerable stage because they do play outside so much and because the damage that they get is cumulative." The actual damage "doesn't show up when they are young, it shows up when they are in their 40s and 50s."

"A lot of work had been done in Australia and some in England," said Kerr. "In particular we were unhappy with the way they were describing the fabrics. . . We can describe the fabrics much better," and that is exactly what this research team has done. Kerr and Capjack have investigated many factors. The team has been working with Dr. Robert Fedosejevs, Department of Electrical Engineering using spectrophotometric techniques to measure the UV light that makes its way through clothing. Different wavelengths have been tested along with the blocking effect of different fibres, fabric mass and color.

Some results are surprising. They show darker clothing protects better than lighter clothing, even though darker clothing absorbs more light. "Generally as the dye gets darker, they should be offering more protection," said Kerr.

Another surprising result is that clothing has a higher sun protection factor (SPF) rating the more it is laundered. "That was unintentional, but it just happened," said Kerr. Most detergents have an optical brightener which absorbs UV rays. Different types of fabrics have different SPF ratings. "Anything with polyester in it, we were finding, contributed to more protection," said Capjack. A light cotton T-shirt can have an SPF rating as low as four and when fabric is wet the SPF usually decreases by one third. That being said, because of their fabric, bathing suits are usually quite good protectors.

There are some specialty clothing companies out there but for the most part fabrics they use can be found locally for cheaper.

One of the areas Kerr and Capjack hope to investigate further are the effects of the optical brightener versus general laundering. As well, they are interested in a psychological investigation of people's attitudes toward skin cancer and sun tanning in general.

"We really would like to target outdoor workers and try to get the message across to them," says Kerr. In fact, this study originally investigated clothing and hats best suited to outdoor workers when Capjack worked for Alberta Agriculture. "People involved in police work are more prone to higher incidence of skin cancer," Capjack said. Thus the work could have fairly wide ranging applicability.

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