Photochemical smog is related to pollution of
A) Air
B) Water
C) Soil
D) Nostoc

Hint: The answer here lies in the fact that smog is the combination of smoke and fog which is caused when the pollutants from the combustion of fossil fuels that react with the sunlight where the pollutants in the atmosphere form smog. This gives the answer.

Complete Solution :
We have come across the concepts of atmosphere related things that include smoke, pollutants and also smog in our chemistry chapters.
Now, let us deal with the photochemical smog formed and the pollution it causes.
- Smog is basically a name given for the combination of smoke and fog or can also be said as ‘The fog or haze which is intensified by smoke or also by the other pollutants of the atmosphere.
- Photochemical smog is nothing but the haze in the atmosphere that is accompanied by high levels of ozone and also gases in the atmosphere like nitrogen oxides present in air that are caused by the action of sunlight.
- The energy of sunlight converts the pollutants formed by combustion of fossil fuels that releases several pollutants and also other volatile organic compounds into the most toxic chemicals that is called photochemical smog.
Thus, the gases or pollutants present in air is responsible for the photochemical smog
So, the correct answer is “Option A”.

Note: Note that this photochemical smog is considered a problem of modern industrialization which is more common in the cities which have sunny, warm or dry climates and as this smog travels with the wind it can affect the populated areas too.