23. The term 'brown air' is used for A.Acid fumes B.Photochemical smog C.Sulphurous smog D.Industrial smog
Answer: Option B Solution: Photochemical smog which is mainly composed of ozone (O3), Peroxyacetyl nitrate (PAN) and Nox, is also known as brown air where solar radiation is intense. In seasons of lesser solar radiation or areas, smog formation is incomplete and the air is referred to as grey air.
