Question

Photochemical smog always contains

• A. methane
• B. aluminium ions
• C. ozone
• D. phosphorus.

Answer 1

Answer: (C)

Smog is a type of severe air pollution. Photochemical smog, often referred to as summer smog, is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leaves airborne particles and ground-level ozone. Photochemical smog depends on primary pollutants as well as the formation of secondary pollutants. These primary pollutants include nitrogen oxides, particularly nitric oxide (NO) and nitrogen dioxide (NO2), and volatile organic compounds. All of these harsh chemicals are usually highly reactive and oxidizing. Photochemical smog is therefore considered to be a problem of modern industrialization. Photochemical (summer smog) forms when pollutants such as nitrogen oxides (primary pollutant) and organic compounds (primary pollutants) react together in the presence of sunlight. A gas called ozone (Secondary pollutant) is formed.

So the correct option is 'ozone'.