AP BIOLOGY

Detailed explanation-1: -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.

Detailed explanation-2: -Molina discovered that chlorofluorocarbons (CFCs) could deplete Earth’s atmospheric ozone layer, which blocks the sun’s damaging ultraviolet rays. When the scientists reported their findings in 1974, CFCs were widely used as refrigerant gases and as propellants in aerosol sprays.

Detailed explanation-3: -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.

Detailed explanation-4: -Ozone depleting substances are chemicals that destroy the earth’s protective ozone layer. They include: chlorofluorocarbons (CFCs) halon.

Detailed explanation-5: -a) Refrigerators and air conditioners – Refrigerants are the most common emitter of CFC. If the coolant used in refrigerators, air conditioners, cars, are not properly disposed it will leak CFCs in the atmosphere. Either the coolant will evaporate or get into the soil, contaminating both with CFC.