The nights are getting longer, days are getting shorter. Temperatures are dropping and people are spending less time outdoors. No need to worry about UV radiation anymore right? Wrong! UV rays are still present, can still cause damage (painful burns and even worse, skin cancer)—and need to be planned for accordingly. While it may be true that people are more exposed to UV rays in the summer time because they spend more time outdoors—the intensity of UV rays is not necessarily affected by the temperature. For example, UVA rays (long wave ray) are equally strong year-round and are the deepest penetrating UV ray (the other is UVB…a short wave ray).
Some factors to consider affecting UV ray strength:
1) Distance from Equator (Latitude). Generally, the closer you are to the equator the more intense the UV radiation will be—the sun is closer to directly overhead and there is less atmosphere (Ozone) to filter the UV rays.
- The strongest rays will be between the Tropic of Capricorn and Tropic of Cancer—this area will have very high levels of UV radiation year-round.
- The Southern United States (S.California, across to Texas and on to Florida) are likely to have higher levels of UV radiation year round.
2) Time of Day. UV rays are strongest around solar noon…which is anywhere from 10AM to 4PM. A short shadow indicates stronger UV rays. This does not mean that outside this time frame the UV rays are weak; it means that extra protection is needed in this time frame as the rays are significantly stronger.
3) Length of Exposure. The longer you spend in the sun, the more UV rays you are exposed to. This does not have to be outdoor sport related; it can be a simple walk to your car in a parking lot on a sunny day.
4) Reflection. Many people do not realize that UV rays can be reflected off a multitude of surfaces. In general, the whiter the surface, the stronger the UV rays. To protect against reflected UV rays: wear higher SPF sunscreen and apply more frequently than normal, and wear polarized sunglasses to eliminate glare. Below are some surfaces and respective UV reflection levels:
- Water and Grass: can reflect up to 5% of UV rays. Apply sunscreen more frequently than usual, because sweat and water will wear the sunscreen off faster.
- Sand and Concrete: can reflect up to 12% of UV rays.
- Snow: can reflect up to 85% of UV rays. Polarized sunglasses in an environment with snow are critical; because the glare off of snow can cause snow blindness. Regular sunglasses will not prevent this, only polarized lenses will.
5) Cloud Cover. It is a common myth that you will not get burned on a cloudy day…but this is totally untrue. Up to 80% of UV rays can penetrate clouds, fog, or haze. Be mindful of this.
6) Ozone. Thinning out of the Ozone layer (which filters UV rays) results in increased exposure to UV rays. There are holes in the Ozone layer over parts of the Arctic and Antarctic, and in other parts of the world.
7) Altitude. The atmosphere is thinner at higher altitudes. There is less Ozone to filter UV rays at higher altitudes. Each 1,000 meters of elevation gain can equate to roughly 10% increase in UV radiation level.
To protect against the sun’s damaging UV rays and help prevent sunburn & skin cancer, it is strongly recommended to wear a minimum SPF 30 sunscreen anytime you will be in the sun—be sure to apply on any exposed skin. Activities like outdoor sports, a beach day, or anything where you will be sweating or getting wet; consider wearing a stronger SPF sunscreen that is also waterproof. Many times this is labeled a “Sport” or “Active” sunscreen. Another option is to wear clothing that covers more skin.
UV rays do not only cause skin damage; over time, the rays that reach the eyes can cause cataracts and other eye tissue defects. You can even get a sunburn on your eye, called photokeratitis (usually it resolves itself in 1-2 days, but still not fun). One way to help prevent UV damage to the eyes is to wear contact lenses offering UVA and UVB protection, like all Acuvue contacts and the popular Biomedics 55 Premier and Avaira lenses. For extra protection, it is recommended that you wear sunshades when outside, like the Von Zipper sunglasses. Discuss with your doctor if your current contact lenses also protect against UV radiation.
Whether the weather has changed makes no difference to UV rays; they are always damaging and need to be guarded against. Take into account that anytime you are outdoors, you are exposed to UV rays—this exposure is magnified by things like altitude, reflective surfaces, and latitude. To prevent painful sunburns, skin cancer, or even eye damage: wear at least SPF 30 sunscreen, clothing that covers potentially exposed skin, sunglasses, and UV protecting contact lenses.