Which among the following is / are principal components of photochemical smog in urban areas?
1. Oxides of Nitrogen
2. Hydrocarbons
3. Ozone
4. Suspended Particulate Matter
Select the correct option from the codes given below:

Answer: [D] 1, 2, 3 & 4

All are principal components of photochemical smog.

This question is a part of GKToday's Integrated IAS General Studies Module