Question

The number of ozone depleters identified by the Vienna Convention for Protection of Ozone Layer (1992) is
(a)19
(b)17
(c)15
(d)13

Answer 1

Hint: The Vienna convention was the precursor of a protocol called the Montreal Protocol which was signed 2 years after the Vienna convention regarding ozone layer depletion. The aim of that protocol was to reduce chlorofluorocarbons CFC emission by half in the next decade.

Complete answer:
The Vienna Convention is the framework for all the actions taken to reduce ozone layer depletion because it was the first time that this issue was discussed internationally in 1958. This convention discussed ozone-depleting chemicals (ODCs) and gave the basis for the Montreal Protocol which was signed in 1987(effective in 1989). 19 ODCs were identified by the Vienna convention.

Additional Information: Let us learn more about ozone depletion.
-Shortly after the Vienna Convention was held, a hole was discovered in the ozone layer over Antarctica by the British Antarctic Survey. This led to the realization that the depletion of the ozone layer was indeed happening and it was much more serious than what was thought before.
-Chlorofluorocarbons present in the stratosphere are broken down into chlorine and chlorine monoxide by solar radiation. These two compounds act as catalysts in the process of converting ${ O }_{ 3 }$ into ${ O }_{ 2 }$ and O. Because they are catalysts they are obtained in the same form after the decomposition of ozone. Thus even as the ozone layer is depleting, the chemicals that are causing this, remain in the same amount in the stratosphere and keep causing the change.
So, the correct option is ‘19.’

Note: -The depletion of the ozone layer will result in the increase of cases like skin cancer, premature aging, wrinkles, etc because harmful high energetic radiation(UVB rays) will reach the surface of the Earth and cause mutations in our body.
-There is also ‘bad’ ozone found in the troposphere which harms plants and animals.
-The thickness of the ozone layer is measured in the terms of the Dobson unit(DU).