Which of the following is a primary air pollutant?

The correct answer is Black carbon.

Key PointsPrimary air pollutants:

• Primary air pollutants are those that are produced and released directly from specific sources.
• Examples: Particulate matter (including black carbon), carbon monoxide, nitrogen oxide, and sulfur oxide.

Secondary air pollutants:

• Secondary air pollutants are those that are produced in the lower atmosphere as a result of chemical interactions.
• Examples: Ozone and secondary organic aerosol (haze).
• Because secondary pollutants synthesise in a variety of ways and the creation is poorly understood, they are more difficult to manage.
• They naturally occur in the atmosphere and result in issues like photochemical haze.

Therefore, the correct answer is black carbon.

Additional Information

• Soot, often known as black carbon, is a fine particle air pollutant (PM_2.5) that causes climate change.
• The incomplete combustion of fossil fuels, wood, and other fuels results in the formation of black carbon.
• The carbon in the fuel would completely burn away to produce carbon dioxide (CO₂), but combustion is never complete and other byproducts such as carbon monoxide, volatile organic compounds, organic carbon, and black carbon particles are also created.
• Soot is a term used frequently to describe the complicated mixture of particulate debris produced by incomplete combustion.