What are the main chemical and biochemical process involved in tanning ?
What are the health and environmental hazards of the above processes ?

Hi! Thanks for the question.

Our first link provides a discussion on the process of tanning.

"The Tanning Process"
http://members.attcanada.ca/~milburnr/process.html

According to the US Food and Drug Administration, here are the
possible health hazards of tanning.

"Skin damage from sunlight builds up with continued exposure, whether
sunburn occurs or not. In addition to skin cancer and sunburn, other
effects can include wrinkling, premature aging, and in time, an almost
leathery appearance of the skin. Research also suggests that excessive
exposure to UV radiation may interfere with the body's immune system."

"Sunscreens, Tanning Products, and Sun Safety"
http://vm.cfsan.fda.gov/~dms/cos-220.html

In the case of indoor tanning, here are the possible health problems.

"Tanning lamps emit chiefly ultraviolet-A (UVA) radiation and this is
far from safe. UVA penetrates the skin deeply and prematurely ages it;
the radiation may damage blood vessels and even inhibit immune
reactions in the skin. It also sensitizes the skin so that sunlight
will be more likely to cause skin cancer."

"Hazards of indoor tanning"
http://www.interiorhealth.ca/Your+Health/Tips+Articles/Tips/Hazards+of+indoor+tanning.htm

Search terms used:
sun tanning process
sun tanning health hazards          
indoor tanning process 
         
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Easterangel-ga          
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Very neat explanations were got.The material was concise and easy to understand.