Part 2 of 4
Clothing can be one of the most basic, simple and effective barriers between our skin and the sun. What makes a piece of clothing sun safe?
Our clothing should cover as much skin as possible. A long-sleeved shirt covers more skin than a T-shirt, especially if it has a high neckline or collar that shields the back of the neck. Long pants cover more skin than shorts.
Many fabric factors contribute to the amount of sun protection. You can have clothing over every square inch of your body, but if the sun goes right through it, it’s not of much use. Fabrics are made of tiny fibers woven or knitted together. Under a microscope, we can see lots of spaces between the fibers; UV can pass directly through these holes to reach the skin. Open weave fabrics provide lesser protection. The tighter the knit or weave, the smaller the holes and the less UV can get through. Consider the fabric’s weight and density — light, sheer silk will provide far less UV protection than heavy cotton denim.
Fabrics can be made from many types of fibers like cotton, wool, and nylon. Most fibers naturally absorb some UV radiation. Some fabrics have elastic threads that pull the fibers tightly together, reducing the spaces between the holes. Synthetic fibers such as polyester, lycra, nylon, and acrylic are more protective than bleached cottons. Shiny or lustrous semi-synthetic fabrics like rayon reflect more UV. Matte ones, such as linen, tend to absorb rather than reflect UV.
Most of our clothing is dyed attractive or functional colors. Many dyes absorb UV, which helps reduce exposure. Darker colors tend to absorb more UV than lighter colors. The more vivid the color, the greater the protection; a bright yellow shirt is more protective than a pale one.
A fabric can be loosely evaluated for its content, colour, weight and weave by sizing it up with the naked eye. Holding it up to the light helps to show how much light passes through, but the human eye sees visible light and not UV rays; hence this will not be ideal. So it is difficult to assess just how protective a piece of clothing is, simply by looking at it.
One solution is to choose garments with UPF labels. UPF is a concept originally standardized in Australia in 1996. UPF stands for Ultraviolet Protection Factor which indicates how much of the sun’s UV radiation is absorbed and how effectively a piece of clothing shields against the sun. The label means the fabric has been tested in a laboratory and consumers can be confident about the listed level of protection. It is based on the content, weight, color, and construction of the fabric, and indicates how much UV can penetrate the fabric.
For instance, a shirt with a UPF of 50 allows just 1/50th of the sun’s UV radiation to reach your skin. This would provide excellent sun protection because only 2 percent of the UV rays will get through. In contrast, a thin white cotton T-shirt, which has a UPF of about 5 allows 1/5th of the sun’s UV through — even more when wet. Even if the piece of clothing has a good UPF, what you do while wearing it can make a difference. If the fabric gets stretched, it will lose some of its protective ability, because the fabric becomes thinner and more transparent to light. And once it gets wet, it can lose up to 50 percent of its UPF.
A number of manufacturers are now making special sun-protective clothing that has been treated with a chemical sunblock during the manufacturing process. We ourselves can improve a piece of clothing’s UPF by first washing it. This generally makes the garment shrink slightly, closing up holes in the fabric that can let UV radiation in. We can wash Sun Protection into our clothes. A laundry additive, Sun Guard, in the USA, contains the sunscreen Tinosorb. When added to a detergent, it increases the UPF of the clothing, and this protection lasts through 20 washing.
Remember, sun-protective clothing doesn’t have to be boring: it can be light and bright and fashionable and fun. And when chosen and used correctly, it’s the best form of sun protection you can find.
Part 2 of 4