Should You Use Internal or External Air Circulation When Resting in the Car?

[DiNicole]

When resting in the car, it is advisable to use the external air circulation mode to ensure proper air ventilation. If the surrounding environment has poor air circulation and the car engine remains running while idling, carbon monoxide produced during idling can accumulate and fail to dissipate. This can lead to carbon monoxide poisoning inside the car, with potentially disastrous consequences. The external circulation mode uses a fan to draw outside air into the car, meaning there is an open airway between the exterior and interior of the vehicle. The air blown by the fan comes from outside, and even if the fan is turned off, airflow will still enter the car while driving, replenishing fresh air inside. Sometimes, you may feel airflow even when the fan is off, which is due to the external circulation setting. However, when driving in congested urban areas, the car may fill with exhaust fumes, as the external circulation mode can draw in vehicle emissions from the road.