Which one of the following is NOT a component of photochemical smog ?

Photochemical smog is a complex mixture formed when sunlight reacts with primary pollutants like nitrogen oxides (NOx) and volatile organic compounds (VOCs) [2]. Key components include secondary pollutants such as ground-level ozone (O3) and peroxyacetyl nitrate (PAN) [1]. Nitric oxide (NO) is a primary precursor emitted from vehicle exhaust that participates in the catalytic cycle of smog formation [1]. While hydrocarbons are essential precursors, Polyaromatic Hydrocarbons (PAHs) are specific complex organic compounds typically associated with incomplete combustion of coal, wood, or forest fires rather than being a defining component of the photochemical smog reaction cycle itself [1]. Standard photochemical smog is characterized by its oxidizing nature, dominated by ozone, PAN, and nitrogen dioxide, whereas PAHs are generally classified as particulate-bound primary pollutants [3].

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Y{r7 $ EilVIAONMEHT > p. 65
2. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > The Formation of Smog > p. 64
3. [3] https://ebooks.inflibnet.ac.in/esp16/chapter/introductory-organic-chemistry/