are the UV rays that help the skin to produce the vitamin D? why do we have to avoid them ?
2007-08-12 06:24:28 · 4 answers · asked by Pimpinella 2 in Science & Mathematics ➔ Biology
UV are simple few rays of sun light and EXPERTS have adviced the sun UV can use to produce vitamin D not more than 15-20 minutes with mild UV index time during the day, because 90% skin problems are from exposure of sun light UVB!
Good because it is cost effective and its useful applications in industrial plants, commercial offices, farming, bio and medical purposes. UVC can sterilize materials, flow of air and water within seconds in tiny spots that the disinfection liquid cant reach them. UVB can cure painting, coating, printing of materials in matter of seconds not hours or apply in fluorescense microscopes, photography; etc. UVA can help cosmetic skin treatment and applications in bio and other sciences.
However, only exposure of high output UV light within few feet to skin can cause permanent damage or direct visual contacts, stairing without protector can impair vision.
2007-08-15 10:06:32 · answer #1 · answered by toodd 4 · 0⤊ 0⤋
UV rays are both good and bad. The lower energy ones are good for vitamin D production. High energy causes cell damage so if you catch too many rays in your life your skin will look like a distressed leather bag. Don't get too much sun and wear sunblock if you want to look good when you get older.
UV rays are also a factor in melanoma, a rather horrible sort of skin cancer and you really don't want that.
It comes in three grades. UV-A is the blacklight that you get in discos and is least harmful. UV-B is the most harmful and we rely on the ozone layer to block much of these rays. UV-C is the most energetic and luckily very rare. The only exposure will be from artificial sources like an arc welder.
2007-08-12 06:30:00 · answer #2 · answered by Anonymous · 0⤊ 0⤋
The same UV rays that can produce vitamin D can also alter DNA, triggering shin cancer.
2007-08-12 06:29:49 · answer #3 · answered by novangelis 7 · 1⤊ 1⤋
To reflect on what Tom said (excuse the pun) the sun rays will bounce back off the water so you need to protect in some area that you normally not cover with sun cream. such as under your nose and arm pit and under arms.
2016-05-20 22:13:48 · answer #4 · answered by ? 3 · 0⤊ 0⤋