Chlorofluorocarbons CFCs are a class of chemicals that were once widely used as refrigerants, propellants, and solvents. They are known to contribute to the depletion of the ozone layer through a series of chemical reactions.The mechanism by which CFCs deplete the ozone layer involves the following steps:1. Release and transport: CFCs are released into the atmosphere through various human activities. Over time, they are transported to the stratosphere, where the ozone layer is located.2. Photodissociation: In the stratosphere, CFCs are exposed to ultraviolet UV radiation from the sun. This radiation causes the CFC molecules to break apart, releasing highly reactive chlorine atoms.3. Ozone destruction: The chlorine atoms react with ozone O3 molecules, forming chlorine monoxide ClO and molecular oxygen O2 . The ClO can then react with another ozone molecule, releasing the chlorine atom and forming two O2 molecules. This process can continue in a catalytic cycle, with one chlorine atom destroying thousands of ozone molecules.The depletion of the ozone layer has several harmful effects on human health and the environment:1. Increased UV radiation: As the ozone layer thins, more UV radiation reaches the Earth's surface. This can lead to an increase in the prevalence of skin cancer, particularly melanoma, as well as other skin disorders such as sunburn and premature aging.2. Eye damage: Increased UV radiation can also cause cataracts and other eye disorders, potentially leading to vision impairment or blindness.3. Immune system suppression: Exposure to higher levels of UV radiation can suppress the immune system, making individuals more susceptible to infections and reducing the effectiveness of vaccines.4. Environmental impact: The depletion of the ozone layer can have harmful effects on the environment, including reduced crop yields due to increased UV radiation, damage to aquatic ecosystems, and potential disruption of the global climate system.Efforts have been made to reduce the use of CFCs and other ozone-depleting substances through international agreements such as the Montreal Protocol. As a result, the production and consumption of these chemicals have significantly decreased, and the ozone layer is expected to recover gradually over the coming decades.