The pollutant least likely to be emitted from a smokestack would be

The pollutant least likely to be emitted from a smokestack would be

• A. Particulate matter
• B. Sulfur dioxide
• C. Nitrogen oxides
• D. Ozone

Answer: (D)

The concept here is distinguishing between pollutants that are released directly from combustion versus those formed in the atmosphere after emissions. Ozone is not released directly from a smokestack. It is a secondary pollutant that forms in the lower atmosphere when precursors like nitrogen oxides and volatile organic compounds react in sunlight. In contrast, particulate matter, sulfur dioxide, and nitrogen oxides are primary pollutants emitted directly by burning fossil fuels and other industrial processes. So ozone is the pollutant least likely to be emitted from a smokestack.

The concept here is distinguishing between pollutants that are released directly from combustion versus those formed in the atmosphere after emissions. Ozone is not released directly from a smokestack. It is a secondary pollutant that forms in the lower atmosphere when precursors like nitrogen oxides and volatile organic compounds react in sunlight. In contrast, particulate matter, sulfur dioxide, and nitrogen oxides are primary pollutants emitted directly by burning fossil fuels and other industrial processes. So ozone is the pollutant least likely to be emitted from a smokestack.