Which one of following is produced during the formation of photochemical smog?

Photochemical smog is characterized by secondary oxidants produced when primary pollutants react under sunlight. Ground‑level (tropospheric) ozone is a principal component produced when oxides of nitrogen (NOx) from vehicle and industrial emissions react with volatile organic compounds (hydrocarbons/VOCs) in sunlight, forming ozone as a secondary pollutant [2]. Authoritative guidance likewise states that ozone is not emitted directly but is formed by photochemical reactions of NOx and VOCs on sunny days, especially in urban areas with heavy traffic and high temperatures [3]. Thus, among the given options, ozone is the species produced during the formation of photochemical smog.

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Y{r7 $ EilVIAONMEHT > p. 65
2. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > ozone depletion > p. 11
3. [3] https://www.epa.gov/ground-level-ozone-pollution/ground-level-ozone-basics