Here is a scenario:
The sun’s UV facilitates the production of ozone. The amount of this ozone is usually balanced out with its natural destruction, caused by chemicals such as nitrogen, hydrogen and chlorine in the atmosphere. But this natural equilibrium is distorted by humans production of more ozone-destroying chemicals, resulting in the destruction of more ozone gas than being produced.
Industries that manufacture things like insulating foams, solvents, soaps, cooling things like Air Conditioners, Refrigerators and ‘Take-Away’ containers use something called chlorofluorocarbons (CFCs). These substances are heavier than air, but over time, (2-5years) they are carried high into the stratosphere by wind action.
Depletion begins when CFC’s get into the stratosphere. Ultraviolet radiation from the sun breaks up these CFCs. The breaking up action releases Chlorine atoms. Chlorine atoms react with Ozone, starting a chemical cycle that destroys the good ozone in that area. One chlorine atom can break apart more than 100,000 ozone molecules.
There are other Ozone Depleting Substances (ODS) such as methyl bromide used in pesticides, halons used in fire extinguishers, and methyl chloroform used in making industrial solvents.
Other chemicals that naturally destroy Ozone are Noy, Hox, Clx, which belong to the Nitrogen, Hydrogen and Chlorine families.
Measurements of CFCs in the stratosphere are made from gas balloons, aircraft and satellites.
Sadly, there aren’t many humans can do to replenish the depleted Ozone, as it tends to recover slowly by itself, but we can be more responsible with our actions precisely our manufacturing needs so that we do not introduce more CFCs into the air.