Vapor-compression refrigeration replaced, such as sulfur dioxide. Haloalkanes are also an order(s) of magnitude more expensive than petroleum derived flammable alkanes of similar or better cooling performance. Unfortunately, chlorine- and fluorine-bearing refrigerants reach the upper atmosphere when they escape. In the stratosphere, CFCs break up due to UV radiation, releasing their chlorine free radicals. These chlorine free radicals act as catalysts in the breakdown of ozone through chain reactions. One CFC molecule can cause thousands of ozone molecules to break down. This causes severe damage to the ozone layer that shields the Earth's surface from the Sun's strong UV radiation, and has
UV filter nm), UVB (290-320 nm) and UVC (200-280 nm ). Ultraviolet absorbing compounds are the active ingredients of sunscreen products and other personal care products (e.g. lipsticks, shampoos, hair sprays, body washes, toilet soaps, and insect repellents). Chemical filters are generally used in combination in order to get sufficient protection against UV. They protect humans from the serious effects of UV radiation by absorbing, reflecting or scattering it. The reflection and scattering effecst are done by physical UV filters which are inorganic UV filters such as titaniumdioxide (TiO) and zinc oxide (ZnO). Absorption is accomplished by organic UV filters which are