Question

The common refrigerant chlorofluoro-methane (freon) and NO${}_2$ is a serious pollutant because

• A. It lowers atmospheric temperature.
• B. It prevents cloud condensation.
• C. It destroys haemoglobin.
• D. It disrupts O${}_3$ layer.

Answer 1

The correct option is D It disrupts O${}_3$ layer.

Pollution leads to the addition of harmful components in the environment which adversely affect the quality of the environment. Ultraviolet radiations are highly energetic radiations which may cause harmful mutagenic changes. The stratosphere present in the atmosphere contains ozone layer which absorbs harmful ultraviolet radiation and protects us from several chronic diseases. There should be a balance between production and degradation of ozone in the stratosphere. The balance has been disrupted due to the enhancement of ozone degradation by chlorofluorocarbons (CFCs). CFCs are used as refrigerants. CFCs discharged in the lower part of atmosphere move upward and reach the stratosphere. In the stratosphere, UV rays act on them releasing Cl atoms. Cl degrades ozone releasing molecular oxygen. Cl atoms are not consumed in the reaction. Hence, whatever CFCs are added to the stratosphere, they have permanent and continuing effects on the ozone layer.