Literature study indicates that drivers spend about 79 min on average each day traveling to their destination. However, continuous driving in an enclosed vehicle can lead to a significant increase in the concentration of contaminants inside the vehicle, especially CO2. Despite this, automotive indoor air quality (IAQ) receives less attention. In this study, a gasoline-powered passenger vehicle was selected to study car cabin IAQ. Sensors were used to measure the concentration of O2, CO, CO2, total volatile organic compounds (TVOCs) and PM10 as well as temperature and humidity in the vehicle. The results revealed that the O2 content remained within adequate levels and TVOCs concentration remained low and safe, with values less than 1 ppm. However, CO2 concentration could exceed 2000 ppm within just 30 min when the ventilation flap was closed, both for idle and driving mode. Opening the flap could lead to increases in carbon monoxide (CO) and PM10 concentrations to more than 10 ppm and 0.15 mg/m3, respectively, particularly during traffic congestion. Even when the ventilation mode is switched to closed circuit mode, exfiltration and infiltration of contaminants may still occur.