UV Rays – How Dangerous Are They?
July is a sunny month, with days spent outside at the ball field, swimming at the pool or enjoying time at the lake. Along with the sun come ultraviolet (UV) rays. July is UV Safety Month and so it is a good time to learn more about ultraviolet rays, risks of UV exposure and how we can protect ourselves from their harmful effects.
When are UV Rays the Strongest?
According to American Cancer Society, sunlight is the main source of UV radiation, even though UV rays make up only a small portion of the sun’s rays. About 95% of the UV rays from the sun that reach the earth are UVA rays, with the remaining 5% being UVB rays. The strength of the UV rays reaching the ground depends on several factors, such as:
- Time of day: UV rays are strongest between 10 am and 4 pm.
- Season of the year: UV rays are stronger during spring and summer months. This is less of a factor near the equator.
- Distance from the equator (latitude): UV exposure goes down as you get farther from the equator.
- Altitude: More UV rays reach the ground at higher elevations.
- Clouds: The effect of clouds can vary. Sometimes cloud cover blocks some UV from the sun and lowers UV exposure, while some types of clouds can reflect UV and can increase UV exposure. What’s important to know is that UV rays can get through, even on a cloudy day.
- Reflection off surfaces: UV rays can bounce off surfaces like water, sand, snow, pavement, or grass, leading to an increase in UV exposure.
- Contents of the air: Ozone in the upper atmosphere, for example, filters out some UV radiation.
The amount of UV exposure a person gets depends on the strength of the rays, the length of time the skin is exposed, and whether the skin is protected with clothing or sunscreen.
Can UV Radiation be Good For You?
Beneficial effects of UV radiation include the production of vitamin D, a vitamin essential to human health. Vitamin D helps the body absorb calcium and phosphorus from food and assists bone development. The World Health Organization (WHO) recommends 5 to 15 minutes of sun exposure 2 to 3 times a week.
Risks from UV Radiation
Overexposure to UV radiation can lead to serious health issues, including cancer. Skin cancer is the most common cancer in the United States. The two most common types of skin cancer are basal cell cancer and squamous cell cancer. Typically, they form on the head, face, neck, hands, and arms because these body parts are the most exposed to UV radiation. Most cases of melanoma, the deadliest kind of skin cancer, are caused by exposure to UV radiation.
Who is Most at Risk from UV Radiation?
Anyone can get skin cancer, but skin cancer from UV radiation exposure is more common in people who:
- Spend a lot of time in the sun or have been sunburned.
- Have light-color skin, hair, and eyes.
- Have a family member with skin cancer.
- Are over age 50.
To minimize your risk of skin cancer from UV Radiation, pay attention to the UV Index and take actions to protect yourself by applying sunscreen over SPF 30+ and wear appropriate clothing. If you are concerned you may be at risk for developing skin cancer or have a suspicious mole, schedule an appointment with a CHI Health Dermatologist today.