Continuously serving Kosciusko County since 1854
Every day the Earth is bombarded with dangerous ultraviolet radiation.
But how does that affect the common Earth dweller?
In 1994, the National Weather Service and the Environmental Protection Agency began what is called the UV index.
According to the EPA, the index is a next day forecast of the amount of UV radiation that will reach the earth's surface during the peak hour of sunlight, typically around noon.
The index is represented by a number from 0-15. The National Weather Service distributes the UV index to selected cities around the world. The two cities closest to Kosciusko County are Chicago and Indianapolis.
The amount of UV radiation that reaches the surface of the Earth is related to the amount of cloud coverage and the motion of the sun in the sky.
Clear skies allow 100 percent of the UV radiation to strike the surface of the Earth. Scattered clouds allow only 89 percent, broken cloud conditions allow 73 percent and overcast skies allow 32 percent of the UV radiation to transfer to the surface.
As the sun rises and begins to move across the sky, the UV index climbs from 0 to the middle teens. The higher the UV index, the greater the dosage rate of skin- and eye-damaging UV radiation.
There are three types of UV radiation. Only two of these reach the Earth's surface because UV-C is completely absorbed by the atmosphere.
UV-B is partially absorbed, but all of the UV-A radiation strikes the Earth.
UV-B radiation is the major contributor to skin cancer. UV-A radiation cause aging, wrinkling, loss of elasticity, and augments the damaging effects of UV-B, including skin cancer and cataracts.
UV radiation is cumulative and damages the eyes as well as being a factor in both types of skin cancer: melanoma and non-melanoma.
The EPA said skin cancer cases have been on the rise. More than 1 million new cases will probably be diagnosed in the United States this year, with 80 percent of the UV exposure occurring before the age of 18.
According to Environment Canada, a Canadian organization devoted to environmental protection, melanoma is the most serious and less common form of skin cancer.
Non-melanoma, which has been confirmed to be caused by UV radiation, occurs in 95 percent of all reported cases of skin cancer. It's not life-threatening if treated quickly.
Malignant melanoma, which scientists believe is also caused by UV radiation, is often fatal.
UV radiation also causes premature aging, or sometimes called photo-aging.
Loss of skin elasticity and wrinkling are effects of both photo-aging and natural aging but they occur much earlier when the skin is exposed to UV radiation.
After a person passes 40 years of age, normal aging begins. Photo-aging begins even before a person reaches 30 years of age.
The early effects of photo-aging include freckling, fine wrinkling and dilatation of capillaries.
Irregular pigmentation, often called liver spots, are later stages of photo-aged skin.
Other health effects of UV radiation include damage to the immune system and cataracts as well as other eye disorders.
The amount of UV radiation that is needed to damage the skin is dependent on several factors.
In general, the darker a person's skin, the longer it will take to cause erythema, or skin reddening.
To determine your skin classification, the EPA suggests that you look at a part of the body that has received the least amount of sun exposure. The lower legs just above the ankles, behind the knee, or the inner side of the upper arm are good places.
Other factors that influence skin classification include genetic history, age, number of previous severe sunburns and medical history. Even within the same classification, individuals can burn at different rates.
Eye damage due to UV radiation, however, has no classifications.
The National Society to Prevent Blindness, the American Optometric Association and the American Academy of Ophthalmology recommend that people wear sunglasses consistently when outside during the sunlight hours.
Wearing a broad-brimmed hat will help shade the eyes and reduce the UV radiation.
The EPA says that sunglasses should be chosen carefully and should absorb 99 to 100 percent of the full UV spectrum.
The EPA has set some general guidelines for protecting yourself against UV radiation:
• Minimal (0, 1, 2) - Apply skin protection factor (SPF) 15 sunscreen.
• Low (3, 4) - SPF 15 & protective clothing (hat).
• Moderate (5, 6) - SPF 15, protective clothing, and UV-A&B sunglasses.
• High (7, 8, 9) - SPF 15, protective clothing, sunglasses and make attempts to avoid the sun between 10 a.m. to 4p.m.
• Very High (10+) - SPF 15, protective clothing, sunglasses and avoid being in the sun between 10 a.m. to 4 p.m.
