Understanding the Important Role of Shade in Sun Protection

Experts advise us to seek shade between 11:00am and 3pm, the hours of the day when solar radiation passes through the least amount of protective atmosphere, allowing large amounts of UV light to reach the surface of the earth. The easy rule to remember is to seek shade if your shadow is shorter than you are tall.

But some shades are more effective than other shades. You can spend long hours under shade and still expose yourself to damaging sun exposure. That is because UVB rays, often considered the most harmful part of sunlight, can reach the skin indirectly. Indirect or diffuse UV light is radiation that has been scattered by clouds or other atmospheric elements and is bounced back from UV reflective surfaces. These surfaces include sand, water, snow, concrete, and white paint on the sides of buildings. So, even if you are sitting under an umbrella at the beach you may still be burned from UVB bouncing up from sand or water. Effective shade at the beach would be a structure with sides blocking indirect ultraviolet rays.

Providing effective shade for yourself and your family may require some planning. Consider the following:

Time of Day. If you are planning the placement of a structure for shade you need to understand the sun’s path and the direction and length of shadow at different times of the day. Decide the times of day when you are most likely to use the structure.

Consider the nearby elements that reflect UVR. As noted, these can include water, sand, sides of buildings, concrete and snow.

When you’ve determined the answers to these questions, decide upon the type of structure that will provide effective shade. And, remember to check the UPF (ultraviolet protection factor) of any fabric you buy.

For complete sun protection, wear sun protective clothing, sunglasses and sunscreen.

Mary M. Barrow is executive director of SunAWARE, a non-profit educational and advocacy group for the prevention and detection of skin cancer. She wrote “Sun Protection for Life: Your guide to a lifetime of healthy and beautiful skin.” She also wrote several books aimed at pre-teens and teens to help introduce safe sun protection habits early in life. She created the SunAWARE educational acronym which has been endorsed and used by a number of leading sun protection organizations. For sun protection advice, educational resources and other information, visit her website at http://www.sunaware.org.