Air conditioning eventually reach the upper atmosphere. Once the refrigerant reaches the stratosphere, UV radiation from the Sun homolytically cleaves the chlorine-carbon bond, yielding a chlorine radical. These chlorine radicals catalyze the breakdown of ozone into diatomic oxygen, depleting the ozone layer that shields the Earth's surface from strong UV radiation. Each chlorine radical remains active as a catalyst until it binds with another radical, forming a stable molecule and quenching the chain reaction. Prior to 1994, most automotive air conditioning systems used R-12 as a refrigerant. It was replaced with R-134a refrigerant, which has no ozone depletion potential. Old R-12 systems
UV filter oxidizing specie is responsible of damaging lipids, proteins and DNA and generating high stress levels in marine organisms. Inorganic UV-filters (i.e. TiO2) can also generate ROS, which is toxic for the marine phytoplankton .The toxicity of nano-TiO is due to its photochemical properties under solar radiation that depend on the radiation intensity, the crystalline structure and the concentration of the nanoparticles. In addition, the inert coating layer of the nanoparticles which protects against photoreactivity is dissolved in aquatic environments after being released from sunscreens. Photolysis is the main abiotic route for transformation of UV filters. Photolysis dissociates the organic filters