UV Rays
UV Rays, commonly known as ultraviolet rays, may not be as common as we think. These rays appear in less than 10 percent of our atmosphere, but it's also been known to cause cancer. The most common type of cancer from these rays is skin cancer; prolong exposure to UV Rays causes erythema (we know it as a sunburn). Sunburn occurs when skin cells are damaged by the absorption of energy from the rays. To make up for this injury, our skin sends extra blood to the already damaged skin in an effort to repair it – we know it as the redness that occurs on our skin. The time it takes for sunburn to occur varies mostly on the amounts of UV damaging the skin and also on a person's skin type. People with darker skin, who have higher levels of melanin, are able to spend longer amounts of time in the sun before burning, while people with fairer skin aren't so lucky; burning for them may occur in a relatively short amount of time. This paper will go into detail about other things that UV rays do; the effects on our skin (both positive and negative), SPF protection (what "usually" protects us from sunburn), what weather does to the rays and how all of this relates to global warming.
UV rays come naturally from the sun; some lamps and tools, that are manmade, also produce UV. UV wavelengths are divided into 3 different categories and are measured in nanometers, or nm. UVA wavelengths, (320 - 400 nm), are slightly affected by ozone levels. Most UVA radiation reaches the Earth and these rays contribute to tanning, aging of the skin, and eye damage. UVB wavelengths, (280-320 nm), are strongly affected by ozone levels. Due to decreases in the ozone in our stratosphere, an increasing amount of UVB radiation is reaching the Earth's surface. This can lead to sunburn, snow blindness and a variety of skin problems including skin cancer and aging prematurely. UVC wavelengths, (100-280 nm), are strongly affected by the ozone levels so the levels of UVC reaching the Earth are relatively small.
UV ray levels are highest during the middle of the day. Almost half the total of the rays are received during the hours around noon. Clouds are a big factor for UV levels but cloudy skies, typically, do not offer protection from UV; thin clouds also have a minor affect on UV, but they raise the amount of UV due to scattering the radiation and that increases the amount of rays that reach Earth's surface.
Animals and people with diseases use the rays to their advantage. Certain animals can see UV light and that is used to their advantage. Bees, for example, use the reflection of UV from their flower petals and that guides them for collecting pollen. UV is necessary for our bodies to make Vitamin D; a vitamin that strengthens our bones and protects us from some diseases. Scientists have shown that the chances of getting some kinds of diseases decrease when using Vitamin D. The light produced from UV is used as therapy for people with psoriasis, a condition that makes the skin shed too quickly. Psoriasis results in itchy, scaly patches on different parts of the body, and when it's exposed to UV light, the growth of the cells decreases and that relieves the symptoms.
People seem to believe that if you can't see the damage given from UV, then it must not appear. Well, that isn't true; one of the effects, from not being cautious of sun tanning, is skin cancer. Skin cancer rates have been increasing, in the US, since the 1970's; melanoma incidents have been on the rise at a rate of 6%, per year, until 1981. Since then, the rate has continued to increase at a rate of 3% per year. {Source: The American Cancer Society Statistics Page at: www.cancer.org}. It is believed that the majority of skin cancer comes from UV rays.
UV rays are reflected towards the eye by something that reflects it, like rain and snow. When this occurs, the amount of UV the eye is exposed to, increases. Photokeratitis, also known as snow blindness, is sunburn of the cornea and typically goes away in a few days. If you tried to look at the sun, you'd find yourself not being able to do so; your eyes would begin to close. If exposures to UV rays continue, cataracts, a condition that is typically seen in older people is caused. This can result in blurred and fuzzy vision.
UV rays also harm phytoplankton in the oceans. This is especially harmful because this type of plankton is the first eaten in marine animals. Differences in plankton's population can shift the balance in less common animals like fish or whales. Some UVB exposure occurs from humans' use of gasoline, pollution due to vehicles, and other types of global warming, both natural and manmade. This can significantly decrease the amount of plankton, and our ozone.
If we continue to not remain cautious of UV rays; the things that make them, and how we can prevent them, we will begin to see a decrease in marine life and an increase in skin cancer. We can easily avoid making life changing mistakes by being aware; when people go to the local beaches, they should lather up on SPF sunscreen protection so that they can remain safe. We shouldn't find out that family members are no longer with us they could've stayed safe by using sunscreen. UV rays have their uses on us all, but they shouldn't be overused and looked upon as an addiction. These rays have a proper place and, they shouldn't be on Earth's entire surface.
