Which gases are commonly tested during an emissions inspection?

During an emissions inspection, carbon monoxide and hydrocarbons are among the primary gases tested. Carbon monoxide is a harmful pollutant produced from incomplete combustion of fossil fuels. It can lead to serious health issues when present in high concentrations in the environment. Hydrocarbons, on the other hand, are compounds made of hydrogen and carbon that can contribute to smog formation and are also indicative of incomplete combustion within the engine.

Emissions inspections focus on these pollutants because they are critical in assessing the vehicle's impact on air quality and determining the performance of the vehicle's emissions control systems. Testing for these gases helps ensure compliance with environmental regulations designed to protect public health.