What type of emissions are typically checked during a vehicle inspection?

During a vehicle inspection, carbon monoxide and hydrocarbons are important emissions that are typically checked because they are key indicators of a vehicle's combustion efficiency and overall environmental impact. Carbon monoxide is a colorless, odorless gas produced from incomplete combustion of fuel, which can be harmful to both human health and the environment. Hydrocarbons are unburned fuel particles that can contribute to smog formation and have negative effects on air quality.

Monitoring these emissions helps ensure that vehicles are running efficiently and within acceptable environmental standards. While visible smoke emissions can indicate a problem, they are not the primary focus of emissions testing during a state inspection. Similarly, soot levels and carbon dioxide levels alone do not provide a comprehensive view of a vehicle's emissions profile. Thus, the inclusion of both carbon monoxide and hydrocarbons in emission checks is crucial for proper assessment and regulation compliance.