When you’re traveling by car, train, or bus, which side do you choose – the sunny side or the shady side? Our insights and recommendations will help you make a more informed decision.
Teresa Larkin, an associate professor at the University of Wollongong (Australia), explained how much ultraviolet (UV) radiation passes through different types of glass that block UV rays and when you should use sunscreen.
Does Glass Block UVA and UVB Rays?
UVA and UVB are two types of ultraviolet radiation that reach the Earth. UVA accounts for about 95 percent, while UVB makes up around 5 percent.
UVB rays only penetrate the upper layers of our skin, but they are responsible for sunburns, cataracts, and skin cancer. UVA rays penetrate deeper and cause cellular damage, leading to skin cancer.
The glass used in windows of homes, offices, and cars blocks UVA and UVB rays to varying degrees.
Only laminated glass can completely block UVA radiation. When this type of UV passes through other types of glass, it can cause skin damage and increase the risk of cancer.
Windshields Offer Better Protection Against UVA Rays
Car windshields block 98 percent of UVA radiation because they consist of two layers of laminated glass. However, side and rear windows made of tempered glass do not fully protect against this type of UV. According to research, up to 56 percent of UVA rays can pass through these windows.
UV protection is not related to the age or class of the vehicle but directly depends on the type of glass, its color, and tinting. Gray or bronze glass, as well as window tinting, are factors that enhance UVA protection. Window tinting blocks about 95 percent of this type of radiation.
The Driver’s Seat: The Highest Risk Zone
Skin cancer poses the greatest threat to those sitting in the driver’s seat or on the driver’s side. A study conducted in the U.S. found more cases of skin cancer on the left side than on the right (specifically on the face, head, legs, and especially – on the arms). Seventy-four percent of cancerous lesions were found in those sitting on the left, while 26 percent were found in those on the right.
American researchers also noted that these cases are more common in men than in women.
Cataracts and other eye damage are also more frequently observed on the driver’s side.
About UV Radiation Penetrating Through Home Windows
We often notice the effects of ultraviolet radiation that seeps through the windows of our homes and offices on faded walls and furniture.
This is not surprising. Most types of glass used in buildings allow a significant amount of UVA radiation to pass through: between 45 to 75 percent. Those who have installed thicker, tinted, or film-coated glass are better protected from this exposure. The best options are laminated glass or double-glazed tinted windows, as reported by Science Alert.
Most modern office buildings are quite well protected from ultraviolet rays. Thanks to the use of cutting-edge technology, the windows in these structures allow less than 25 percent of UVA to pass through. Some “smart” windows block radiation due to special chemical treatments.
Sunscreen and Sunglasses
Should you use sunscreen when exposed to direct sunlight? It depends on your skin type and the season, as well as whether the glass is tinted.
If your car windows are tinted, you don’t need to use sunscreen during your trip.
However, keep in mind that in a car without tinted glass, you can get sunburned in just one hour during the summer midday and in two hours during the winter midday.
Meanwhile, sitting by a window in your home, you can get sunburned in just half an hour in the summer and one hour in the winter. As for sunglasses, they should be worn while driving or sitting near a window in your home if the UV index exceeds 3. Remember, there are 13 levels of the UV index. The higher the level, the greater the risk to your skin and eyes.