Written By Dr. Paul M. Graham
For many years, dermatologists have observed an increase in skin cancer incidence and aging occurring on the left side of the face more than the right. How can this be? Well, the answer is quite simple and easy to understand. Reuters published a report regarding the lack of sun protection, specifically UV-A radiation, of car window glass. This article explicitly states that car door windows offer little protection against the damaging UV-A rays of the sun. Putting this together, the left side of our face has more exposure to damaging UV rays than the right secondary to driving practices in the United States.
What is Ultraviolet Radiation?
To help further understand the damaging effects UV radiation, we will briefly explain how this occurs. The sun emits three types of UV radiation; UV-A, UV-B, and UV-C. The shortest and least important of these rays is UV-C. UV-C has a very short wavelength and is not able to penetrate the ozone, thus blocking it from reaching the Earth’s surface. UV-B does, however, reach the Earth’s surface and is responsible for the redness that is seen after long periods of exposure to the sun, AKA a sunburn. Luckily, window glass completely blocks UV-B radiation. The most important and least likely to be blocked by car window glass is UV-A. UV-A is the most damaging type of ultraviolet radiation secondary to its ability to penetrate deeply into the skin. This depth of penetration allows for the production of destructive chemicals, termed free radicals, that contribute to cell damage and aging. UV-A rays are the primary culprit for the appearance of wrinkles and discoloration of aged skin.
With this information, it is important to keep in mind that car door windows offer varying levels of protection from UV-A rays and can lead to the development of skin aging, skin cancers, and cataracts. Interestingly enough, ophthalmologist report a much higher incidence of cataract development in left eyes compared to the right. They contribute this occurrence to the lack of UV-A protection from conventional side window glass in many cars. Windshields offer more protection from UV-A rays because of its shatter-resistant laminated properties. However, car door windows are tempered glass and lack this UV-protective lamination.
So what does this all mean?
It is imperative to practice good sun protection while driving. This entails wearing long sleeve clothing, an SPF 30+ broad-spectrum sunscreen, and UV-protective sunglasses. With these simple practices, the damaging UV rays of the sun will have minimal damaging effects on your skin. In the future, I suspect and hope that the Federal Motor Vehicle Safety Standards and Regulations Committee will implement a policy to mandate the installation of car door windows that offer complete UV-A protection. In the meantime, make sure to use the above sun-protective measures when long drives are anticipated.
Refer to our articles on SPF for more information on sun protection: SPF: What does it really mean?, Sun Protection: The Burning Truth, How Effective Is Your Sunscreen? , Sunburn: What Can I Do?, Beware Of A Base Tan
Photo Credit: Cetaphil, Healthnewsline.net
References: http://www.reuters.com/article/us-health-uv-windows-idUSKCN0Y32WI
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