Free radicals come from various different sources to which people are exposed everyday. In general, free radicals come from airborne emissions, sunlight, chlorination, chemicals and pollutants.
A free radical is a molecule or atom with an unpaired electron, which makes the molecule or atom unstable and highly reactive. There are over 1100 different families of free radicals. Continuous exposure to free radicals is harmful as it brings about oxidation and cellular deterioration.
Some free radicals are produced as natural by-products of reactions in cells. Cigarette smoke and ultraviolet radiation are also considered major sources of free radicals.