Final answer:
The reaction of Volatile Organic Compounds (VOCs) and Nitrogen Oxides (NOx) in the presence of sunlight results in the formation of ozone (O3), a secondary pollutant associated with photochemical smog.
Step-by-step explanation:
When Volatile Organic Compounds (VOCs) and Nitrogen Oxides (NOx) react in the presence of sunlight, they form a secondary pollutant known as ozone (O3). This reaction occurs during the formation of photochemical smog, which is a significant air quality issue, especially in urban environments on hot sunny days. The formation of ozone from these compounds is initiated by UV light causing the dissociation of NO2 into NO and O, which then reacts with oxygen to form ozone.