Ozone is good at trapping a type of radiation called ultraviolet radiation, or UV light, which can penetrate organisms’ protective layers, like skin, damaging DNA molecules in plants and animals. There are two major types of UV light: UVB and UVA.
Ozone molecules, which are simply made of three joined oxygen atoms, are always being destroyed and reformed naturally. But CFCs in the air make it very difficult for ozone to reform once it’s broken apart.
Ozone is only a trace gas in the atmosphere—only about 3 molecule s for every 10 million molecules of air. But it does a very important job. Like a sponge, the ozone layer absorbs bits of radiation hitting Earth from the sun. Even though we need some of the sun's radiation to live, too much of it can damage living things.
“Ozone holes” are popular names for areas of damage to the ozone layer. This is inaccurate. Ozone layer damage is more like a really thin patch than a hole. The ozone layer is thinnest near the poles.
Scientists also discovered that the thinning in the ozone layer was caused by increasing concentrations of ozone-depleting chemicals – chlorofluorocarbons or CFCs (compounds with chlorine and/or fluorine attached to carbon) and to a lesser extent halons (similar compounds with bromine or iodine).
The ozone layer is getting thinner. Chemicals called chlorofluorocarbons (CFCs) are a reason we have a thinning ozone layer. A chlorofluorocarbon (CFC) is a molecule that contains the elements carbon, chlorine, and fluorine. CFCs are everywhere, mostly in refrigerants and plastic products.
These compounds contribute to ozone depletion, and are called ozone-depleting substances ( ODS. ODS include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, hydrobromofluorocarbons, chlorobromomethane, and methyl chloroform.
Chlorofluorocarbons or CFCs are the main cause of ozone layer depletion. These are released by solvents, spray aerosols, refrigerators, air-conditioners, etc. The molecules of chlorofluorocarbons in the stratosphere are broken down by ultraviolet radiations and release chlorine atoms.
the polesThe thickness of the ozone layer varies worldwide and is generally thinner near the equator and thicker near the poles.
A team of scientists measured the total amount of ozone in the atmosphere and found that the overall concentration is about the same as it's been, despite a measured boost in the upper layer. That discovery led the team to surmise that the lower level of the ozone layer is still getting thinner.
Once in the atmosphere, CFCs drift slowly upward to the stratosphere, where they are broken up by ultraviolet radiation, releasing chlorine atoms, which are able to destroy ozone molecules.
NO + O3 <---> NO2 + O2 90% of the earth's atmospheric ozone is contained in the stratosphere, which explains why this equilibrium reaction tends towards the destruction of ozone rather than its production.
Scientists accept that the depletion in the ozone layer is caused by human-made gases called CFCs, which were first developed in the 1930s for use in refrigeration systems and were then deployed as propellants in aerosol spray cans. The chemicals are stable so can travel from the Earth's surface to the stratosphere.
The depletion of ozone causes the harmful UV rays to reach the earth and this has resulted in increased incidence of skin cancers in humans. UV rays may also cause genetic mutations in living organisms. To limit the damage to the ozone layer, the release of CFCs into the atmosphere must be reduced.
Manufactured chemicals, precisely manufactured halocarbon solvents, refrigerants, foam-blowing agents, and propellants are the ozone-depleting substances or ODS, known to be the main cause of depletion of the ozone layer.
Ozone depletion can cause increased amounts of UV radiation to reach the Earth which can lead to more cases of skin cancer, cataracts, and impaired immune systems. Too much exposure to UV is believed to be contributing to the increase in melanoma, the most fatal of all skin cancers.