The use of ultraviolet light is an attempt to imitate nature. Present are of course advantages and disadvantages of UV rays. The advantages of UV rays is that it gives no taste or odor, and it is automatic, as well as the UV disinfection is effective at inactivating most viruses, spores and cysts, as UV disinfection is also user-friendly for operators. UV rays also assure that there is no residual effect that can be harmful to humans or aquatic life. UV rays also form Vitamin-D, as it is proved resistant to infection, and has a general tonic effect. The special bulbs called ``black lights'' produce a lot of UV and were used by hospitals to kill bacteria, amoebas, and other micro-organisms.
However, there are many disadvantages as there are advantages. Some of the disadvantages are that low dosages of UV rays may not effectively inactivate some viruses, spores and cysts, and there is no measurable residual to indicate the efficacy of UV disinfection. UV rays could also cause conjunctivitis (eye infection), reddening of skin, electric shock, burns and skin cancer.
As mentioned above excessive UV rays could cause skin cancer. Ultraviolet light has high enough energy to damage our skin cells, so our bodies will produce a darker pigment in our skin to prevent exposure of the deeper skin cells to the UV (we tan as a defense mechanism). One of the variables that increase the incidence of skin cancer is the greater intensity of UV-radiation that is reaching the earth's surface - this increase is due to an unprecedented thinning of the Stratospheric Ozone Shield.
The ozone layer is very important because it stops too many of the sun’s UV rays getting through to the Earth. Too much UV can cause skin cancer and will also harm all plants and animals. Life on Earth could not exist without the protective shield of the ozone layer. The ozone layer is like a sunscreen, a thinning of it would mean that more UV rays would be reaching us.
One way of protecting your skin from skin cancer, is by applying sun tan lotion. However, there is a problem to this solution. Sun tan lotion can cause pollution to marine life, as well as if a person has sensitive skin, sun tan lotion might not be a good idea, as it might not affect their skin, or protect it from UV rays. Tanning is another way the skin protects its cells from the sun: the pigment melanin helps skin cells more safely absorb UV radiation.
Ultraviolet radiation effects the environment as well as the society. As mentioned before, UV rays can travel through water and end up killing small water animals or plants, called ‘plankton’ which form the base of the food chain in marine life (oceans and seas). Whales and other fishes have plankton as their main food, and if plankton dies because of these UV rays, whales will start dying too, because they will not have anything to eat. Large amounts of UV rays could damage all green plants. If the ozone layer keeps getting thinner, there could be fewer and fewer plants on Earth, and then there would be less food in the whole world.
UV rays also affect the society in many ways. This is because too many UV rays would cause more sunburn, and because sunburn causes skin cancer, this too would increase deaths. These UV rays are also dangerous for our eyes and could cause an increase in people becoming blind. That is why sun cream and sunglasses are very important.
Overall, ultraviolet radiation does have many uses, advantages as well as disadvantages, effects on the society and environment, and it could cause skin cancer and blindness, and death to many marine lives. Because of UV rays and sunlight, sun tan lotion and sunglasses have become a very important part of our life and the environment that we live in.
Bibliography
NASA. "Electromagnetic Spectrum." 27 Mar. 2007. National Aeronautics and Space Administration
(NASA). Doha, Qatar. 5 Nov. 2007 <http://science.hq.nasa.gov/kids/imagers/ems/
index.html>.
Saddleback Valley Unified School District, Kristal Pride. "Properties of Light." 11 Oct. 1999. UCI
Summer Science Institute 1999. Doha, Qatar. 5 Nov. 2007 <http://can-do.com/uci/lessons99/
light.html>.
Astronomy Notes, Nick Strobel. "Electromagnetic Radiation - Properties of Light." 17 May 2001.
Astronomy Notes. Doha, Qatar. 5 Nov. 2007 <http://www.astronomynotes.com/light/s3.htm>.
ARIC. "Atmosphere, Climate and Environment." ARIC - Information and Teaching Resources. Doha, Qatar.
5 Nov. 2007 <http://www.ace.mmu.ac.uk/kids/ozonehole.html>.
"Free Drinking Water." APEC. Doha, Qatar. 5 Nov. 2007 <http://www.freedrinkingwater.com/
water-education2/86-water-disinfection1.htm>.
"Types of Physiotherapy - UV rays." 5 Nov. 2007. Medindia Health Network . Doha, Qatar. 5 Nov. 2007
<http://www.medindia.net/patients/patientinfo/physiotherapytypes_uv.htm>.
U.S. Environmental Protection Agency, et al. "Ultraviolet Disinfection." 1998. National Small Flows
- Clearing House. Doha, Qatar. 5 Nov. 2007 <http://www.nesc.wvu.edu/nsfc/pdf/eti/
UV_Dis_tech.pdf>.
Simonetti, John. "Frequently Asked Questions About Light and Lasers." Virginia Tech Physics. Doha,
Qatar. 5 Nov. 2007 <http://www.phys.vt.edu/~jhs/faq/light.html#q6>.
