Let us see the cause, effect and how there is ozone layer depletion or thinning.
Causes of ozone layer depletion:
1. An ozone hole or depleted ozone layer does not signify a hole in the ozone layer but rather a portion of the ozone layer that has become thinner.
2. Ozone layer destruction is mainly caused by chlorine atoms in chlorofluorocarbons (CFC) molecules.
3. Nitrogen monoxide can also cause the depletion of the ozone layer.
4. Hydrochlorofluorocarbons (\(HCFCs\)), carbon tetrachloride (\(CCl_4\)), methyl chloroform, and volatile organic compounds (VOC) are the other chemicals that deplete the ozone layer. They can be found in smoke from automobiles, factories, aerosols, refrigerants, etc.
Effects of ozone layer depletion:
The following are the negative consequences of ozone depletion:
1. Due to the depletion of the ozone layer, UV radiation from the sun directly affects living organisms.
2. Depleting the ozone layer causes various health problems, including skin cancer (malignant melanoma, squamous cell carcinoma, etc. ), sunburns, skin ageing, eye impairment (cataract), and immune system weakness. Breathing difficulties and throat inflammation are the additional hazards of ozone layer depletion.
3. As the ozone layer depletes, plant growth, development and the time of flowering shifts for a few plant species.
How does CFC cause depletion of the ozone layer?
CFCs is comprised of both chlorine and fluorine. CFCs are extremely stable and are not destroyed by natural processes. CFCs are dissociated by UV radiation in the outer atmosphere (\(25-40\) \(km\) above sea level), releasing free chlorine atoms.
Destruction of the ozone layer
The free chlorine atoms break down the ozone molecules (\(O_3\)) into oxygen (\(O_2\)). Thus, there is depletion of the ozone layer, which protects life from their destructive effects. The ozone layer's thinning would thus allow UV radiation to penetrate the earth's atmosphere, causing adverse side effects like mutations.
Ozone hole creation in the stratosphere
A video that explains what ozone is and how the ozone layer gets depleted:
Steps to control ozone layer depletion:
Controlling ozone layer depletion can be done in the following ways.
1. Every individual can help reduce ozone layer depletion by taking public transportation, buying recycled products, conserving electricity, etc.
2. Refrigerators and air conditioners that do not use CFCs as a refrigerant can be used.
3. Preference should be given to those aerosols that do not contain CFCs or HCFCs.
4. When repairing air conditioners or refrigerators, care should be taken by transferring the refrigerant to a recycling machine rather than exposing it to the atmosphere.
5. Spreading public awareness about the causes, impacts, and controlling measures of ozone layer depletion.
6. Since this is not a problem limited to a single country, international agreements to restrict CFC emissions from industries can be developed.
Montreal protocol, \(1987\):
The depletion of the ozone layer is a global issue, and environmentalists are developing strategies to control the thinning of the ozone layer. The United Nations Environment Programme (UNEP) successfully negotiated an agreement between the nations to limit CFCs production deal to half the level of \(1986\). All manufacturing companies are now required to produce CFC-free refrigerators all around the world.
The protocol was developed to help safeguard the earth's ozone layer by stopping the production and import of ozone-depleting substances for lowering their concentration in the atmosphere.