With reference to smog consider the following statements 1 Smog is a combination of various gases wi...........

Geography (CDS) Pollution

With reference to smog, consider the following statements:

1. Smog is a combination of various gases with water vapor and dust.

2. Photochemical is also called ‘reducing smog’.

3. Classical smog is caused by high concentrations of sulphur oxides in the air due to use of sulphur-bearing fossil fuels like coal.

4. Photo-chemical smog requires neither smoke nor fog.

Which of the above statements are correct?

1 and 2 only

1 and 3 only

1, 3 and 4 only

2, 3 and 4 only

Smog :

The term smog was fi rst used in 1905 by Dr. H A Des Voeux to describe the conditions of fog that had soot or smoke in it.
Smog is a combination of various gases with water vapor and dust.
There are 2 distinct types of smog:
Classical Smog/Sulfurous Smog/ London Smog:
It is caused by high concentrations of sulphur oxides in the air due to use of sulphur-bearing fossil fuels like coal.
Since sulphur oxides are reducing agents, it is also called ‘reducing smog’.
It is particularly formed in the morning hours of winter months when the temperatures are low. Hence it is known as ‘winter smog’.
This type of smog is aggravated by dampness and a high concentration of suspended particulate matter in the air.