Who is the largest user of ozone depleting agents?

Answer 1

This answers "what" the largest contributor(s) to ozone depletion is.

The largest contributor to ozone depletion is nitrous oxide. A recent (2009) article is written on the matter, called "Nitrous Oxide (N2O): The Dominant Ozone-Depleting Substance Emitted in the 21st Century." Nitrous oxide has natural causes as well as human causes and is not regulated like CFCs are.

One of the largest Man-sourced ozone depleting agent still in use is water vapor. This is being produced by aircraft that deliver their relatively tiny amounts of water vapor (and remove some oxygen from the air in the process, which disallows some ozone from being made from it) right up close to and in the ozone layer, fossil fuelled power plants (especially the ones with nice tall smoke stacks to deliver their pollutants far downwind), then as very small contributors cooling towers, fossil fuel powered vehicles, and the extensive networks of man-made lakes. So the "Who" is all of mankind.

There is still some production of CFC in the third world, because:

1. it is cheap and easy to make,
2. their own infrastructure will not work with the newer compounds,
3. there are consumers in the civilized that will buy it, that are too damned cheap to convert over.

Nature makes a good bit of chlorine containing compounds, but where Man burns forests or organic garbage, which also causes the release of things like chloromethane, which also are shown to deplete ozone.

When we ask who to point a finger at, we always end up with three or four fingers pointing back at ourselves. See the question(s) below for more.

Answer 2

Historically, the largest user of ozone-depleting substances has been the refrigeration and air conditioning industry, specifically through the extensive use of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) in cooling systems. However, regulations such as the Montreal Protocol have significantly reduced the use of these substances globally.