What is the impact of cold starts on emissions?

The impact of cold starts on emissions is significant because vehicles tend to generate higher emissions during the initial startup when the engine is cold. This occurs because the engine and its components, such as the catalytic converter, need to reach an optimal operating temperature to effectively reduce harmful emissions. When the engine is cold, fuel combustion is less efficient, leading to incomplete combustion and an increase in pollutants such as hydrocarbons and nitrogen oxides.

During a cold start, the catalytic converter is not yet at a temperature where it can function optimally, further contributing to higher emissions. This phenomenon applies to most internal combustion engines, regardless of the vehicle type, thus emphasizing the importance of minimizing cold starts where possible for emissions control.