All you need to know about Ultraviolet Radiation!


Ultraviolet radiation, commonly known as ultraviolet rays, like all other waves, is energy voyaging through space. This type of electromagnetic radiation contains more energy than visible light as it has a shorter wavelength than the latter. Specifically, the wavelength of ultraviolet radiation is between 100 nanometers to 400 nanometers. How does earth obtain ultraviolet radiation? Sun is the chief contributor to the earth’s ultraviolet radiation.  We all have heard that ultraviolet rays are harmful to human health, but most of us are unaware of why that is so.

But before we delve into the detrimental effects of ultraviolet rays and why they happen, let me salvage its image a bit. Ultraviolet rays are not as evil and undesirable as we think. They do have a place in the normal functioning of our planet earth. Ultraviolet rays contain vitamin D that toughens our bones and shields us against countless diseases. Ultraviolet light has also been employed by us for healing diseases like psoriasis. Psoriasis is a skin condition whereby the skin sheds its cells rapidly, and ultraviolet rays help in slowing the cell growth. Some animals can see the ultraviolet rays and use them to benefit themselves. For example, bees use ultraviolet light to help in pollen collection.

How is Ultraviolet radiation harmful to us?

The main savior, our protector against this mostly toxic Ray, is the ozone layer. Hence, the depletion of ozone layer has given ultraviolet light free reign on earth. As previously mentioned ultraviolet rays contain energy. Energy is good, energy helps the earth function. But the same energy in an unregulated amount can be disastrous. As Swami Vivekananda said, “everything excess in life is poison”, the same applies to ultraviolet radiation. Ultraviolet light can be said to have an inordinate amount of energy. This immoderate energy causes electrons to leave the orbit of the atoms thereby changing the molecular structure. This phenomenon is also called mutation. The mutation causes several deformities.

Types of Ultraviolet Radiation

Ultra-Violet rays can be categorized into different classes, each deadly and harmful in its unique way. Ultraviolet rays can be classified into mainly three types based on their wavelength:

  • UV-A: This has the longest wavelength of the three and can penetrate the deepest. This causes skin tanning during overexposure. It also causes premature skin aging and even wrinkling.
  • UV-B:  It has a shorter wavelength than UV-A and hence can’t penetrate very deeply into the skin. It too causes tanning and also causes burning. Exposure to ultraviolet-B causes skin cancer.
  • UV-C: It is the deadliest of all the types but is fortunately absorbed by the ozone layer and earth’s atmosphere.


Effects of Ultraviolet Radiation on Human Health

The ultraviolet rays present in the environment are referred to as human carcinogens and they have severe effects on human health. A few are listed below:

  • Skin Damage: Prolonged exposure to ultraviolet radiation can cause severe skin damage in a variety of ways.

o   Sunburn, also known as “erythema”, occurs when the skin absorbs a lot of energy from UV rays. The redness that you suffer from during sunburn is because extra blood is being sent to the damaged part of the skin. The amount of time taken by the ultraviolet rays to damage the skin varies person to person. A fair skinned person’s skin may get damaged faster as compared to a darker skinned person.

o   The next risk associated with skin damage is sun tan. To fight against the damage causing ultraviolet radiation, the brown pigment present in your skin, also known as melanin, increases. The sole purpose of melanin is to absorb the UV radiation and dissipate the energy as heat thus disallowing it from damaging the skin tissue.

o   Ageing of the skin: Another health effect of ultraviolet radiation is premature ageing of the skin. Studies have been conducted which suggest that ageing symptoms such as wrinkles, loosening of the skin, etc. can be related to UV exposure. Ultraviolet rays kill skin cells and damages skin connective tissue which cause wrinkles at later stages of life. All the three types of ultraviolet rays – UVA, UVB and UVC have been found to damage collagen fibers, speeding up the ageing process of the skin. UVA and UVB are also known to destroy vitamin A present in the skin, causing further extensive damage.

Your skin might look normal but in reality, it might not be as healthy as you think. In this picture, clicked in front of a special UV camera, the left side represents the skin damaged by UV/sun and the right side represents how we actually see our skin in normal light.

o   Skin Cancer: Exposure to ultraviolet radiation, specifically UV-B, can cause skin cancer. 90% of skin carcinomas have been associated to prolonged UV-B exposure, which are rarely fatal and can be effectively treated if diagnosed early.

There are various kinds of skin cancers associated with ultraviolet radiation. One of the main one being cancer of the pigment cells, formed by the cutaneous melanomas.

The other main types of skin cancer associated with skin cancer are basal cell carcinomas and squamous cell carcinomas – the cancer of the epithelial cells also known as non-melanoma skin cancer. This type of cancer is found majorly in fair skinned people exposed to a lot of sunlight.

  • Genetic Damage: Ultraviolet radiation has an effect on our DNA as well. UV rays, especially the UV-B rays, harm the DNA of different living organisms in different ways. The energy from the UV rays is absorbed by the body and this energy breaks the bonds present in DNA. When there is damage in the bond of the DNA, the proteins present in the body repair the damage or, at least, a part of it. But increased exposure to UV-B damages the repair system itself causing the DNA to be damaged permanently. The damaged DNA can cause various problems including skin cancer and the distorted DNA molecule does not function properly.
  • Effect on Eye: High-intensity exposure to ultraviolet B or UVB light can be very hazardous to the human eye. The exposure to such rays may lead to cataracts, pterygium, and pinguecula formation.  Exposures to ultraviolet radiations also have an impact to the cornea. The cornea is a good absorber of ultraviolet rays and too much exposure can cause clouding of the cornea. Eye cells and tissues have ‘chromophores’, a molecule that absorbs UV rays. Too much of UV rays can harm the cornea, the retina and the lens of the eye as well.
  • Effects on the Immune System: As mentioned earlier, exposure to ultraviolet radiation damages the cells and the tissue components of the body. These damaged cells and tissues are deemed foreign by our own immune system and removed. One might think that removal of damaged tissue or cells is good but it isn’t. UV rays also reduce the fighting capabilities of your body against harmful bacteria present in your body. Damaging of the immune system – your body’s natural way of fighting against diseases – increases the risk of infection.


Prevention against Ultraviolet Radiation

Here are a few things you can do to protect you against the harmful ultraviolet radiations.

  • Clothing: Slip on some clothing to prevent the sunlight reaching your skin, not just to look good. You can look for clothing which has been specially treated to absorb ultraviolet radiations. Such clothing is usually marked with the ‘UPF’ label. Furthermore, you can wear layers to increase protection against UV.
  • Wear a hat: Wear a hat that provides shade to your face, neck, ears and your head. Again choose a hat that is made of a fabric specially treated to absorb UV rays.
  • Sunglasses: Put on a pair of sunglasses with a high anti-UV factor to protect your eyes from being damaged.
  • Shade: Stand or wait in the shade instead of being directly beneath the sun. But remember this is not a standard protection against UV. Ultraviolet rays can bounce off surfaces and reach you even if you are in the shade.
  • Sunscreen lotion: There are a wide variety of sunscreen lotions available in the market. Choose one which protects your skin from a wide spectrum of ultraviolet radiations. Lotions are marked with an ‘SPF’ factor which helps you understand the power of blocking of the sunscreen lotion.

This picture, again clicked by a special UV camera, shows how sunscreen lotion actively blocks UV rays. It looks black in front of the UV camera as it is effectively blocking UV rays.

  • Avoid being the sun during peak hours if possible. If not, use one or more of the methods listed above before stepping out of the house.


Ultraviolet radiations have a disastrous effect on our planet and on our health. It is a part of nature that we have to protect ourselves from. UV rays can lead to widespread disasters ultimately leading to the end of mankind. It’s high time that we create awareness among ourselves about the impact ultraviolet radiation can have our health because, as always, prevention is better than cure!

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