Stratosphere around at midlatitudes, and at about at the poles. Temperatures range from an average of near the tropopause to an average of near the mesosphere. Stratospheric temperatures also vary within the stratosphere as the seasons change, reaching particularly low temperatures in the polar night (winter). Winds in the stratosphere can far exceed those in the troposphere, reaching near in the Southern polar vortex. The mechanism describing the formation of the ozone layer was described by British mathematician Sydney Chapman in 1930. Molecular oxygen absorbs high energy sunlight in the UV-C region, at wavelengths shorter than about 240 nm. Radicals produced
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