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

The correct answer is Nitrogen oxide.

Key Points

• Nitrogen oxides (NOx) are primary pollutants involved in the formation of photochemical smog, a type of air pollution typically seen in urban areas.
• These oxides are emitted mainly from vehicle exhaust, industrial processes, and power plants burning fossil fuels.
• During sunlight exposure, nitrogen oxides react with volatile organic compounds (VOCs) to form harmful secondary pollutants, such as ozone (O₃).
• Photochemical smog is most common in areas with high population density and heavy vehicular emissions, especially during warm, sunny days.
• Inhalation of smog can lead to severe respiratory and cardiovascular health issues.

Additional Information

• Photochemical Smog:
  • It is a type of air pollution formed through the reaction of sunlight with pollutants like nitrogen oxides (NOx) and VOCs.
  • Major components of photochemical smog include ozone (O₃), peroxyacetyl nitrate (PAN), and aldehydes.
  • It is also known as "Los Angeles smog" as it was first studied in Los Angeles, USA, in the 1940s.
• Nitrogen Oxides (NOx):
  • NOx includes nitric oxide (NO) and nitrogen dioxide (NO₂), which are major air pollutants.
  • They play a key role in the formation of ground-level ozone and acid rain.
  • Prolonged exposure to NOx can cause respiratory problems, reduced lung function, and increased susceptibility to infections.
• Volatile Organic Compounds (VOCs):
  • VOCs are organic chemicals that easily evaporate into the atmosphere.
  • They are emitted from sources such as vehicle exhaust, industrial processes, and household products like paints and cleaners.
  • When VOCs react with NOx under sunlight, they contribute to the formation of secondary pollutants like ozone.
• Ozone (O₃):
  • Ozone is a harmful secondary pollutant formed in the troposphere during photochemical smog formation.
  • While stratospheric ozone protects us from UV radiation, tropospheric ozone is a health hazard.
  • It causes respiratory irritation, reduces lung function, and damages crops and vegetation.