UV Index explained: How much sun is too much?

ROANOKE, Va. (WDBJ) - Summertime in the Blue Ridge means spending time with family, friends, and enjoying time outdoors. All this fun likely means more exposure to the sun. It’s easy to forget to reapply sunscreen or to protect your skin from the harmful ultraviolet (UV) radiation. However, prolonged sun exposure can be dangerous for your health.

WHAT IS UV INDEX?

The UV Index is a valuable tool that helps us understand how strong the sun is and what type of protection we should use. The higher the UV index, the greater the strength of the sun’s UV rays, and the faster we could be overexposed or sunburned.

The index uses a scale from 0 (low risk) to 11+ (very high risk). The forecast must consider cloud cover, elevation, latitude, and time of year. The index values vary throughout the day, peaking between the hours of 10am-2pm, which is sometimes called “solar noon.”

The sun’s rays are strongest in the summer, but also at the equator. If you are close to the Gulf, you’re more likely to be sunburned. UV radiation is also stronger at high altitudes. Objects like clouds, water, sand and snow can also reflect or scatter the sun’s rays.

You’ll know you’re experiencing high UV radiation when your shadow is shorter than you. If your shadow is taller than you, UV is low, but you should still protect yourself from the sun.

Experts recommend applying sunscreen with a sun protection factor (SPF) 30 or higher anytime the sun is out and reapplying it every two hours. When the UV index is higher, it’s better to seek shade or limit your time outdoors to prevent sun damage.

THE THREE TYPES OF UV RADIATION

There are three types of UV rays that are emitted from the sun.

• UV A: The first is UV A, which accounts for 95% of all ultraviolet radiation. UV A can increase your risk for skin cancer and has the ability to pass through car windows and clouds. This is why it’s important to apply sunscreen even on a cloudy day. UV A can also cause premature aging.
• UV B: The second type is UV B, which is more dangerous than UV A. It is the primary cause of sunburn and is the main cause of skin cancer. UV B is responsible for producing vitamin D on your skin, which is essential to human health. Most sunscreen is made to protect you from UV B radiation.
• UV C: The most dangerous type of UV radiation is UV C. Luckily; UV C rays are absorbed by the ozone layer in the atmosphere before reaching the surface. However, there are some artificial sources of UV C, such as tanning beds.

WHAT LEVEL OF SPF SHOULD YOU WEAR?

It can be overwhelming when there are so many sunscreen options with different levels of SPF. Regardless of skin color, age, and time of day, experts strongly recommend that you wear sunscreen whenever you are outdoors.

Sunscreen can range from SPF 4 to SPF 100. The number represents how protected you are from the sun’s harmful UV B rays. For example, SPF 30 means it will take 30 times as long for your skin to burn than it does without sunscreen.

However, there isn’t much of a difference between SPF 30 and SPF 100. SPF 30 blocks 97% of UV B rays, and SPF 100 blocks 99%. It’s a common myth that sunscreen prevents people from tanning. Regardless of SPF level, your skin can still tan while being protected from the harmful radiation.

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