Red Seal Automotive Service Technician Practice Exam

Which of the following is not a basic type of vehicle emission?

1. Carbon dioxide (CO2)

2. Nitrogen oxides (NOx)

3. Ozone (O3)

4. Carbon monoxide (CO)

The correct answer is: Ozone (O3)

Ozone (O3) is considered a secondary pollutant rather than a primary vehicle emission. It is not directly emitted from vehicles but rather forms in the atmosphere through chemical reactions involving primary pollutants, such as nitrogen oxides (NOx) and volatile organic compounds (VOCs), in the presence of sunlight. This process typically occurs in urban areas where vehicle emissions are prevalent. In contrast, carbon dioxide (CO2), nitrogen oxides (NOx), and carbon monoxide (CO) are all directly emitted from the combustion of fuels in internal combustion engines. CO2 is a greenhouse gas produced during fuel combustion, NOx refers to gases that contribute to smog and acid rain, and CO is a toxic gas that results from incomplete combustion. Their classification as basic types of vehicle emissions reflects their direct release into the atmosphere as a result of vehicular activity, setting them apart from ozone.