The most abundant hydrocarbon pollutant is : 
1. Methane
2. Ethane
3. Propane
4. Butane

Photochemical smog formed in congested metropolitan cities mainly consists of : 

1. Ozone, SO₂, and hydrocarbons.

2. Ozone, PAN, and NO₂

3. PAN, smoke and SO₂

4. Hydrocarbons, SO₂, and CO₂

The aromatic compound that is present as particulate among the following is : 

1. Benzene

2. Toulene

3. Nitrobenzene

4. Polycyclic hydrocarbons

Air pollution from the leakage of methyl isocyanate gas from the union carbide factory in Bhopal caused a major tragedy on:

1. Dec. 2, 1984

2. Dec 15, 1983

3. Dec.10, 1982

4. Dec. 4, 1988

‘White lung cancer’ is caused by : 

1. Asbestos

2. Silica

3. Textiles

4. Paper

Gas that is not a pollutant is : 

1. Carbon monoxide

2. Nitrogen peroxide

3. Carbon dioxide

4. Sulphur dioxide

A gas that has the greatest affinity for hemoglobin is :

1. CH₄

2. NO

3. O₂

4. CO₂

Incorrect statement among the following is: 

1. Oxides of sulphur, nitrogen, and carbon are the most widespread air pollutant.

2. pH of drinking water should be between 6.5 and 8.5.

3. Concentration of dissolved oxygen below 6 ppm is good for the growth of fish.

4. Clean water would have a BOD value of less than 5 ppm.