Life under the sun

People who work around x-rays, or who are exposed to them during cancer treatment, often keep track of how much radiation they’ve absorbed. You’ll see nurses and technologists wearing little film-badge dosimeters on their lapels that record their personal exposure. The objective is to minimize dose, as radiation over time can cause cancer.

It’s one of life’s cruel little jokes: using a cancer-killing agent can itself cause cancer. Radiation is the archetypal double-edged sword.

I’d love to see an equivalent measurement device developed for ultraviolet light, which is also a potential carcinogen. Sunlight has the advantage of being visible, which x-rays aren’t. Anyone who invents a UV exposure badge could sell millions as people become more aware of the skin cancer epidemic. Combined with the epidemic in obesity, we're talking about a lot of roasted blubber.

I don’t need to be told to come in out of the sun, especially on a scorcher like today. But I do like spending time outdoors, usually with hat and sunglasses. Having had a melanoma removed from my leg, I’m at risk for developing a second primary cancer. The odds are not as high in my case as they are for a metastasis, but I’m not taking chances. I’m learning to be sensible about my sun exposure. It ain't easy--or cheap.

When I last visited my dermatologist, I asked her if she had a sample of a good sunscreen. She said she did, and then produced a box filled with at least $50 worth of samples—all with an SPF value of at least 30. I hate applying sunscreen, which leaves my skin feeling oily, but at least for now I don’t have to worry about buying any.

I’ve also ordered some SPF clothing—a lightweight athletic jacket and a long-sleeved bamboo-fiber shirt. It would take a materials scientist to describe how UV-protective textiles are made, but suffice to say they’re based on electrospun zinc oxide nanocomposite fibers. Got that? The advantage of wearing clothing like this is that it obviates having to smear on sunscreen, and to reapply it regularly. I’ve read that the clothes block 98% or so of all UVA and UVB rays, which of necessity I take on faith.

I've also learned that there are a number of factors that affect the level of UV protection provided by a fabric. In order of importance these are weave (tighter is better), color (darker is better), weight (heavier is better), stretch (less is better) and wetness (dry is better). Recently, the addition of chemicals such as UV absorbers or UV diffusers during the manufacturing process has become another way to create UV protection in fabrics.

In my efforts to avoid the sun, I draw the line at umbrellas. You will not see me approaching a microphone holding a black brolly a la Michael Jackson.

A study was done a few years ago of who would most likely wear sun-protective clothing. The researchers found two groups: 1) people who had already suffered a skin cancer or had other medical conditions that made them sun sensitive, and 2) Australians. Aussies have the highest rate of skin cancer in the world, but the rate of increase is now almost flat because of public awareness of the risks of UV exposure. Americans have yet to get the message.

If you’re interested in knowing more about how to enjoy summer without being damaged by the sun, I invite you to visit this blog: http://sunaware.org/blog/.