UV (Ultra Violet) is a ray invisible to the human eye. UV rays are produced by sunlight and tanning lamps and beds. UV radiation with a wavelength of 254 nm destroys viruses and microorganisms.
Ultraviolet lamps are used in RO UV water purifiers or air purifiers for home to disinfect water, air and various surfaces in all spheres of human activity.
Check out my UV water purifier comparison.
Ultraviolet treatment of water, air and surface does not have a prolonged effect. The advantage of this feature is that it excludes the harmful effects on humans and animals.
UV light penetrates the cell’s membrane, kills the DNA, and stops its reproducing.
There are 3 kinds of UV rays:
- UVA rays (315-400 nm) age skin cells causing wrinkles and damage their DNA provoking skin cancer incidences. UVA rays are used for most tanning beds give in large amounts.
- UVB rays (280-315 nm) are stronger a little than UVA and cause the most damage. They directly damage skin cells’ DNA and cause sunburns. They are also the reason for most skin cancers.
- UVC rays (100-280 nm) have the stronger energy than any types of UV, but they can’t get through our atmosphere layer. They don’t come with sunlight and don’t cause skin cancer.
UV rays exposure depends on many factors, such as:
- Time: UV exposure is stronger from 10 am to 4 pm. Reapply sunscreen, look for shade or layer up with clothing at this time.
- Season: UV rays are stronger at spring and summer.
- Distance from the equator: UV exposure gets down when you get further from the equator.
- Altitude: The higher elevations the more UV rays reach the surface. So if you are on a winter holiday in the mountains – you will get higher UV exposure.
- Clouds: Cloud cover may block UV rays coming from the sun and lowers UV exposure. Anyway, UV rays can filter through the clouds.
- Reflection off surfaces: UV rays can reflect off surfaces like water, snow, sand, pavement, grass and increase its exposure.
The amount of UV a person gets depends on the strength of the rays, the period of time the skin is exposed, and whether the skin is covered with clothing or sunscreen. Those living in locations with year-round sunlight have a higher risk of getting skin cancer.
Frequent sunburns in childhood may cause some kinds of skin cancer years or decades later.
The main danger of UV radiation exposure is a risk factor for skin cancer. Researches show that 90% of skin cancers are caused by UV rays. UV rays damage the DNA of skin cells and cancers start developing when the damage affects the DNA of genes controlling skin cell growth.
That’s why ultraviolet radiation causes mutations (ultraviolet mutagenesis).
Each year, about 130,000 cases of malignant melanoma are registered in the world.
Spending a lot of time outside without sunscreen or covering clothing increases cancer and skin damage risks. Long-term exposure changes skin appearance causing early skin aging, losing skin elasticity, wrinkles, dark patches, and actinic keratoses.
The UV rays lead to the risk of cataracts and other eye problems, suppress the skin’s immune system that protects the body from microbes, bacteria, viruses, toxins, and parasites. People having dark skin are less prone to get skin cancer, but they still have the risk to get cataracts and immune system suppression.
About 12 to 15 million people in the world lose their sight every year due to cataracts.
Very long exposure of UV radiation causes degenerative changes in skin cells, fibrous tissue, and blood vessels.
The most effective ways of protection from ultraviolet radiation are clothing and special anti-tan creams with the “SPF” higher than 10. This number indicates the attenuation coefficient of the exposure.
For example, the number 30 means that you can stay under the sun for 30 hours and get the same exposure as in one hour, but without protection.
To protect the eyes from the harmful effects of ultraviolet radiation, special protective glasses are used. They hold up to 100% ultraviolet radiation. As a rule, the lenses of such glasses are made of special plastics or polycarbonate.
The UV Index
The UV Index developed by the National Weather Service and the Environmental Protection Agency (EPA) helps people find out the strength of UV light in a certain area on a certain day. There is a scale from 1 to 11+ where a higher number means higher UV rays strength and a higher risk of sunburn and skin damage.
Of course, sunlight plays an important role in creating vitamin D. It helps make bones and muscles stronger, and boosts the immune system. It also lowers the chance of getting colon cancer. 5–30 minutes of sun exposure from 10 am to 3 pm 2 times a week without sunscreen on your body is enough for getting sufficient vitamin D levels.
A tan may look good now, but you can pay for it with wrinkly skin or skin cancer later. Take care of your health and use cosmetics that protect the skin from ultraviolet rays while resting in nature or sunbathing in the solarium.