Should You Use External or Internal Air Circulation When Driving on the Highway?

[LaMax]

It is recommended to use external air circulation when driving at high speeds on the highway, and switch to internal circulation when the external air quality is poor. This helps maintain air circulation inside the vehicle and keeps the air fresh. Prolonged use of internal circulation can lead to excessive carbon dioxide levels in the car, causing drowsiness and fatigue, which increases driving risks. The external and internal air circulation systems in a car play a crucial role in cycling air from inside and outside the vehicle, helping to maintain an optimal temperature inside the cabin. Keeping the car sealed for extended periods can result in poor air quality, and unhealthy air intake can negatively affect the body. Driving at high speeds on the highway is generally faster, and most highways are located in suburban areas. As long as there is no traffic congestion, the air quality is usually acceptable—much better than in urban areas. Many drivers prefer to switch between external and internal circulation when the external air environment is good. However, there is another consideration: the high speed of highway driving. Under normal circumstances, when external air circulation is activated, small openings under the front hood of the car allow for air convection. However, the engine compartment houses the engine, which generates significant heat. When external circulation is on, hot air from outside can be blown into the cabin at high speed through these openings. While the air conditioning can mitigate this effect to some extent, it may require adjusting the temperature settings to compensate.