Despite the worldwide trend of introducing of zero-fuel-based vehicles to the market, the emissions of air pollutants and greenhouse gases from passenger vehicles are likely to remain a concern for the coming 20 to 30 years. In this study, exhaust emissions of gasoline engines running after varying parking durations were measured using a chassis dynamometer. The experimental results showed that exhaust emissions of hydrocarbons, nitrogen oxides, and carbon monoxide from most vehicles increased dramatically following 60 to 120 min of parking, and were higher than cold-start (1040+ min parking) emissions, indicating the impact of parking duration on atmospheric pollutant emissions. The after-treatment capacity of the three-way catalytic converter was evaluated by chemical kinetic modeling of the chemical reactions on the catalyst coupled with a time-dependent energy conservation equation. The results of the model calculation indicated that both the initial temperature of the three-way catalytic converter and the inlet engine gas temperature are critical factors impacting exhaust pollutants after parking; therefore, proper management to reduce the emissions after middle-term parking durations should be developed to mitigate air pollution.
