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.
This stratospheric ozone layer protects the Earth from the UV rays of the sun for more than billions of years.
If the ozone layer is worn out by human action, the consequences on the planet could be disastrous and appalling, an understanding that is just about dawning on mankind.
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.
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.
Thesis Ozone Layer Depletion
The first measurements were taken in 1985, and the drop in stratospheric ozone levels in was thought to be due to instrumental faults.Polar stratospheric clouds (PSCs) acts as the medium on which reservoir chlorine compounds are converted chlorine radicals and promote denoxification.Essentially there are two types of PSC: known as type 1 and type 2.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.The ozone layer is a region of naturally occurring ozone gas about15 to 30 kilometers above Earth’s surface in the stratosphere.Only 10 or less of every million molecules of air are ozone.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.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.