The main component of photochemical smog isans.Sulphur dioxideOxides of nitrogenAll of the aboveWater vapour  Previous Marked for Review Save & Finish

The main component of photochemical smog is Oxides of Nitrogen.

Here's a step-by-step explanation:

1. Photochemical smog, also known as "Los Angeles smog," is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes.

2. These pollutants contain harmful molecules such as oxides of nitrogen and volatile organic compounds.

3. When sunlight acts on these gases, they form airborne particles and ground-level ozone—or smog.

4. Therefore, among the options given, Oxides of Nitrogen is the main component of photochemical smog.

5. Sulphur dioxide is a component of industrial smog, not photochemical smog. Water vapour is not a primary component of smog, but it can contribute to its formation.