What is UV radiation and why is it harmful?

UV radiation has been linked to several types of skin cancer, as well as some other cancers. Even though it comes from the sun and is natural, there are behaviors that can overexpose us to sunlight, and cause skin damage. Common issues like sunburns or liver spots can develop into something more serious over time.

So what exactly is UV radiation?

UV radiation is a form of electromagnetic radiation that mainly comes from the sun. There are three types of UV rays: UVA, UVB and UVC rays. UVA rays are the weakest, but they cause skin cells to age faster. UVB rays are a little stronger, and can cause sunburns and skin cancer. UVC rays from the sun react with the ozone and do not reach the ground. However, they can also come from man-made sources, like welding torches, mercury lamps and UV sanitizing bulbs made to kill bacteria.
Sunlight is main source of UV radiation. The sun is usually strongest between 10  a.m. and 4 p.m., although a location’s distance from the equator, altitude, clouds and surface reflections can also determine where and when the sun is strongest. UV radiation from the sun can be blocked with clothes and sunscreen. It is also important to wear hats and sunglasses in bright sunlight, as well as trying to stay in the shade as much as possible.
UVB rays from the sun can cause basal and squamous cell skin cancer and melanoma. They have also been linked to Merkel cell carcinoma, a less common type of skin cancer, and cancer of the lip and eye. Avoiding overexposure to the sun is tricky, when getting no sunlight is not advisable either. Sunshine provides vitamin D, which we need to be healthy. Scientists have been unable to determine what the correct amount of vitamin D to get without being exposed to too much sunlight, but are working on finding a solution.

Are you at risk for skin cancer?

Certain behaviors are linked to skin cancer caused by UV radiation. Common activities that involve prolonged sun exposure, like going to the beach, can increase risk of skin cancer. Even just living in an area with a lot of sunlight can increase your sun exposure and risk.
Look out for common signs of sun damage, like
  • serious sun burns
  • liver spots
  • patches of rough or damaged skin
  • thickened, dry skin on the neck
All of these signs of sun damage and activities have been linked to cancer risk.
Avoiding exposure to sunlight mostly relies on covering your face and body when outside. Hats can help protect the face, and covering areas of your body not often exposed to sunlight or that are more sensitive to sunburns will help protect your body. Lip balm with SPF and sunglasses protect the lips and eyes from UV rays. Sunscreen is extremely important as well, and should be applied anywhere that you are not wearing clothing. In locations with strong sunlight, sunscreen should be applied regularly.
Man-made sources of UV radiation have also been linked to cancer. There are types of artificial sunlight, like sunlamps and tanning beds, that emit UV rays like the sun. Lab studies have determined that simulated sunlight can cause DNA mutations just like real sunshine. People who use tanning beds oftentimes lay in them for a long time, which is extremely dangerous. Exposure to radiation depends on the length of time spent in the bed and frequency of use. Tanning beds can be particularly damaging if used before the age of 20.
Phototherapy, a treatment for some skin diseases like psoriasis, involves a drug that makes you more sensitive to UV rays. There are other medicines that can also make you more sensitive to sunlight and prone to sunburns, so make sure you know if you might need extra sun protection. Black lights, often used in clubs, give off UVA rays.
Although UVA rays are the weakest type of UV rays, frequent exposure to them is not good for you. Those who work with black lights should be extra careful about their exposure. Mercury vapor lamps do not expose people to UV rays when working properly, but if broken, they will emit UV rays. Mercury vapor lamps are often used to light to public areas like streets or gyms, so being aware of the possible harmful effects is important.   
Xenon-mercury lamps and high-pressure xenon are riskier substances. Used in curing ink, coatings, video projection, fiber optics, disinfection and car headlights, UV radiation is present in several everyday objects. Be careful about long-term exposure to those items as well. Certain welding materials like plasma torches and welding arcs can also emit UV rays. These are linked to melanoma of the eye, so make sure your eyes are suitably protected before doing any metal work.
Other health issues caused by UV rays include signs of sun damage, rash, sunburn and premature aging. Eye problems caused by UV radiation include inflammation of the cornea, cataracts and pterygium, which cause impaired vision. UV radiation can also weaken the immune system, which can lead to infections spreading faster.
Skin cancer is one of the most common types of cancer, so avoiding exposure to UV radiation is extremely important. Protect yourself by staying in the shade, make sure you always remember your sunscreen and sunglasses, and check your body regularly for signs of skin cancer.