Photochemical smog type – UGC NET Question

Photochemical smog arises from photochemical reactions between nitrogen oxides and volatile organic compounds under strong sunlight. It produces secondary pollutants such as ozone and peroxyacetyl nitrate,leading to eye irritation and respiratory problems. The stem clearly refers to this sunlight driven reaction in urban environments. Hence photochemical smog is the correct term.

Option A:
Classical smog,also called London smog,is associated with high levels of sulphur dioxide,smoke and fog in cool,humid conditions. It is different in composition and meteorological setting from the sunlight dependent smog described in the question.

Option B:
Industrial smog is a broader term for pollution arising from industrial emissions,especially in older coal burning cities. While it may contain particulates and sulphur compounds,it is not defined by photochemical reactions involving nitrogen oxides and hydrocarbons.

Option C:
Photochemical smog typically occurs in sunny, warm climates with heavy vehicle traffic. It is characterised by brownish haze and high ozone levels near the ground. These features correspond to the conditions outlined in the stem,so this option is accurate.

Option D:
Dust haze results primarily from suspended dust particles in the air,which reduce visibility. It is not a secondary pollutant arising from complex photochemical reactions. Therefore it does not match the description in the question.