Remember that geography class you hated in high school? Well, it's about to finally come in handy in helping you evaluate the UV risk where you live.
People who live at higher altitudes or live closer to the equator are more exposed to UV rays and are at greater risk of UV-related skin and eye damage.
According to the National Oceanic and Atmospheric Administration (NOAA), UV exposure increases 4 to 5 percent for every 1,000 feet of elevation.
For example, the amount of UV exposure you would experience in Flagstaff, Arizona, is roughly 25 percent greater than in Phoenix (due to about 6,000 feet in elevation difference). But if you visit Flagstaff for a skiing vacation in winter, you also have to factor in the added reflection of UV rays from snow. In this scenario, your UV exposure would go from 27 percent higher (due to elevation alone) to approximately 100 percent higher, since snow reflects approximately four times more UV than desert sand.
UV exposure also increases the closer you are to the equator, where the sun is closer to the earth's surface. UV radiation also is stronger near the equator because the ozone layer of the atmosphere, which filters some UV rays, is thinner in this region.
It's important to wear sunglasses to protect your eyes from UV damage wherever you live. But it's especially important in areas of greater UV intensity.
UV Map Index: See today's local UV levels.