WHAT ARE ULTRAVIOLET RAYS? ARE THEY HARMFUL TO HUMANS?
- UVA, or near UV (315–400 nm)
- UVB, or middle UV (280–315 nm)
- UVC, or far UV (180–280 nm)
Most of the natural UV light people encounter comes from the sun but only about one-third of this penetrates the atmosphere to reach the ground. 95 percent is UVA and 5 percent is UVB. No measurable UVC from solar radiation reaches the Earth's surface, because ozone, molecular oxygen and water vapor in the upper atmosphere completely absorb the shortest UV wavelengths. UVA and UVB are the strongest and most damaging to living things on Earth.
Positive effects of UV rays
⦁ Allow Vitamin D production
UV from the Sun is needed by our bodies to produce vitamin D. As we all know, vitamin D helps strengthen bones, muscles and the body’s immune system.
⦁ Helps in moods
It was suggested by research that sunlight stimulates the pineal gland in the brain to produce certain chemicals called ‘tryptamines’. These chemicals improve human’s mood, making them happy and joyous.
⦁ Disinfection and sterilization
UV can effectively kill microorganisms such as viruses and bacteria, for example, when hanging underwear and tea-towels outside under the sun. To destroy the microorganisms, UV rays penetrate the cell's membrane, destroying the DNA, and stops its ability to reproduce and multiply. This destructive effect explains why we can use UV antibacterial lamps for disinfection and sterilization.
Negative effects of UV rays
⦁ Causes skin cancer
There is a strong evidence that each of the three main types of skin cancer (basal cell carcinoma, squamous cell carcinoma and melanoma) is caused by sun exposure. As many as 90% of skin cancers are due to UV radiation so it’s safe to say that UV rays are the cause of skin cancers due to the research results.
⦁ Causes sun burn and aging skin
UV burns the skin hence that is why sun burn occurs when we are under the sun for too long. Sun burn is a burn that occurs when skin cells are damaged. This damage to the skin is caused by the absorption of energy from UV rays. If not taken care of, your skin will lose its elasticity as UV rays destroy collagen.
⦁ Damages eyes
Prolonged exposure to UV or high intensities of UV damages the tissues of eyes. It will cause blurred vision, “burned” eyes or even worst, cataracts, which left untreated, will cause blindness.
⦁ Discolouration of materials
When exposed to the sun, items such as fabrics, furnishings and paintings will eventually fade in the long run. These items need protection from UV to uphold the condition and colours.
In conclusion, UV rays are indeed dangerous to not only humans, but also non-living things. There are definitely benefits of UV rays, but the negative effects overshadows the positive. To avoid the damaging effects of UV rays, we should start protecting ourselves and try to avoid the sun light as much as possible. Doesn’t mean you’re indoors, you are protected. UV rays penetrate through windows. Small steps such as wearing sun glasses and sun block while under the sun and install window films for your home, car and office will make a whole lot of difference.