Under what conditions do cars emit the most carbon monoxide?

[VanAustin]

Cars emit the most carbon monoxide when idling with the engine running. The combustion chamber of a car engine tends to produce carbon monoxide when operating at high temperatures. When idling with the engine on but no load, the fuel burns without doing work, causing the combustion chamber temperature to remain high, which makes it more prone to producing carbon monoxide. Carbon monoxide is a carbon oxide compound with the chemical formula CO. Under normal conditions, it is a colorless, odorless, and tasteless gas. Physically, carbon monoxide has a melting point of -205 degrees Celsius and a boiling point of -191.5 degrees Celsius. Chemically, carbon monoxide exhibits both reducing and oxidizing properties, capable of undergoing oxidation reactions and disproportionation reactions, while also being toxic.