Which gas must vehicles in Maine not exceed in terms of permissible emissions?

In Maine, one of the critical emissions that vehicles are monitored for is carbon monoxide. This gas is a byproduct of incomplete combustion of fossil fuels and can be harmful to human health when present in high concentrations. The state has set regulations to limit the amount of carbon monoxide that vehicles can emit in order to ensure air quality and public safety.

Carbon monoxide is particularly concerning because it binds with hemoglobin in the blood more effectively than oxygen, which can lead to a lack of oxygen in the body and serious health issues. Therefore, establishing permissible emissions for carbon monoxide helps to mitigate these health risks and promotes cleaner air.

While other gases like nitrogen oxides and sulfur dioxide are also regulated due to their environmental and health impacts, carbon monoxide has specific thresholds that vehicles must adhere to during inspections in Maine.