Should You Use External or Internal Air Circulation When Driving in Winter?

[LaMalachi]

Whether to use external or internal air circulation when driving in winter depends on the situation. In winter, when the outside air quality is poor, such as during fog or smog, it is advisable to turn on the internal air circulation. This prevents outside air from entering the car and only recirculates the air inside the vehicle, which helps to keep particulate matter from the outside air from entering the car. When the outside air quality is good, you can switch to external air circulation, which uses the fan to draw outside air into the car, promoting air exchange between the inside and outside of the vehicle and replenishing fresh air inside the car. During high-speed driving, prolonged use of internal air circulation can lead to an increase in harmful substances such as carbon dioxide inside the car. In such cases, it is necessary to switch to external air circulation to refresh the air inside the car, maintain air freshness, and help prevent driver fatigue.