Tags: Solved Problems On Time Value Of MoneyCommunication And Problem Solving SkillsHow To Write The Best College EssayEssay On Fear In The CrucibleTopics For Psychology Research PaperPhd Dissertation In International RelationsEasy Scholarships For High School Seniors 2013 No EssayDragons Den Business PlanApplication Of Critical Thinking
Considerable loss of ozone in the lower stratosphere was first noticed in the 1970s over Antarctica, by a research group from the British Antarctic Survey (BAS), who were monitoring Antarctic atmosphere that time.The first measurements were taken in 1985, and the drop in stratospheric ozone levels in was thought to be due to instrumental faults.One chlorine atom can destroy about 1,00,000 ozone molecules, before it reacts with methane, nitrogen dioxide or itself .
CFCs to undergo photo dissociation in presence of UV radiation, producing highly reactive chlorine free radicals.
dichloro difluoro methane Chlorine free radicals may then react with ozone, thus destroying it from the atmosphere. Formation and decomposition of ozone in the stratosphere continues, the oxygen free radicals present can react with Cl O free radicals to reform chlorine free radicals: Cl O O --- Cl O2 Cl O free radicals can undergo photodissociation alternatively to reform chlorine free radicals Chlorine free radicals reformed begins the process again, resulting in a chain reaction.
Other compounds containing bromine and other halogen compounds, nitrogen oxides (NOx) are also responsible for ozone depletion.
CFC's are a common industrial product, Nitrogen oxides are mainly released as by-product of combustion processes, such as aircraft emissions.
Instruments were replaced and later, ozone depletion was accepted as genuine fact. "One Dobson Unit is the number of molecules of ozone that would be required to create a layer of pure ozone 0.01 millimeters thick at a temperature of 0 degrees Celsius and a pressure of 1 atmosphere".
Generally, the air has an ozone measurement of 300 Dobson Units, equivalent to a layer of 3mm ozone thickness.It plays a key role in development of malignant melanoma.UVB is also linked to cataract of eyes -- a clouding of the eye’s lens.Antarctica is completely surrounded by water and geographically isolated from air at higher latitudes during the winter season.These results into an isolated air mass whirling above Antarctica called the south polar vortex.PSCs I are supposed to be nitric acid and water mixtures that forms just above the frost point and can be either solid or liquid subjected on the conditions.PSCs 2, less common, are formed of water-ice crystals at lower temperatures.With arrival of winter, a vortex of wind develops around the pole and isolates the polar stratosphere.The temperatures falls to very low levels in the stratosphere in this polar vortex, below 80 degrees, resulting in the formation of thin clouds of ice, nitric acid, and sulphuric acid mixtures.Antarctic temperatures below −88 °C (−126 °F) are quite often but such low temperatures are rarer in the Arctic.Every time 1percent of the ozone layer is depleted, 2 percent more UV-B is able to hit the surface of the Earth.