Olympiad Test: Pollution of Air & Water - UPSC MCQ

Which of the following air pollutants is wrongly matched with the effect it causes?

A) Dust - reduces photosynthesis in green plants.

B) Carbon monoxide - reduces oxygen in the blood.

C) Chlorofluorocarbons - lead to the depletion of ozone layer.

D) Nicotine - hardens and narrows blood vessels

Air pollution is not caused by increasing forest reserves.

Carbon dioxide is normally not an atmospheric pollutant. It is required by green plants to carry on photosynthesis. Green plants, use carbon dioxide to synthesize carbohydrates. However, excessive release of carbon dioxide by automobiles, industries and other anthropogenic activities leads to atmospheric pollution. This is because carbon dioxide is a green house gas and is a major gas contributing in global warming.

Carbon dioxide causes global warming, which is the same as greenhouse effect. Hence, the gas is called greenhouse gas

The release of carbon particles and smoke from factories decreases the rate of photosynthesis in plants.

Oxides of sulphur i.e., sulphur dioxide and sulphur trioxide gases present in air combine with moisture and form acids, which come down along with rain water. This is called acid rain. 

Heat reflected from the earth's surface is trapped in the atmosphere. This is referred to as the greenhouse effect. 

Sewage comes from domestic waste or municipal waste from sewers, which does not include any industrial waste but only untreated sewage from local residential or commercial areas.
Oil spills can occur when petroleum products or fuel is leaked from ships or the tankers carried by them. Pesticides are used in farms and plantations, while smoke is released from automobiles, machines, factories, etc.

SO₂ is regarded as an air pollutant.

Sulphur dioxide in air affects the skin and the lungs of human beings

Burning of leaded petrol in automobiles releases lead particles into the air and causes pollution.

Ozone layer present in the atmosphere protects us from UV rays by preventing them from reaching the earth.

Monuments of marble can be destroyed by acid rain because acid corrodes calcium carbonate (marble). The pollutants in air that cause acid rain are oxides of sulphur and nitrogen.

Aerosols are the sources of major pollutants like CFC?s. 

A major air pollutant in cities like Delhi and Kolkata is suspended particulate matter.

Automobiles use catalytic converters like platinum. These acts as catalysts to convert CO to CO₂.

A combination of smoke and fog is smog.

CO₂ traps heat and does not allow it to escape into space. Hence, if there is no CO₂ in the atmosphere, the earth's Temperature would be less than the present.   

Potable water should be free from sodium, calcium and magnesium. Potable water should be clean, colourless and odourless, free from bacteria and must contain dissolved oxygen and carbon dioxide.

Ammonia is not present in vehicular exhaust emissions.