Which of the following play a role during the formation of photochemical smog?

1.NO2 (nitrogen dioxide)

2.Black carbon

3.Sunlight

4.VOCs (volatile organic compounds)

5.CO (carbon monoxide)

A1, 2 & 3 only

B1, 3 & 4 only ✓ Correct

C1, 4 & 5 only

D2, 3, 4 & 5 only

Correct answer: (B) 1, 3 & 4 only

Explanation

Nitrogen dioxide, sunlight and VOCs, Statements 1, 3 and 4, together drive photochemical smog.

Sunlight, Statement 3, supplies the energy that splits nitrogen dioxide and starts the reactions.

Nitrogen dioxide, Statement 1, and VOCs, Statement 4, react to form ozone and other oxidants.

Black carbon, Statement 2, is soot that darkens air but does not power the photochemical reactions.

Carbon monoxide, Statement 5, plays only a minor role and is not a main smog former here.

The resulting ground-level ozone and PAN irritate the eyes and lungs.

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