2. If there is a skylight, the skylight can be opened properly. When it is driving at high speed, the roof is in a negative pressure state, and the dirty air in the car will be sucked away.
When driving forward, due to the headwind, a small amount of air will be pushed into the car through the air conditioning duct, generally speaking, there will be no lack of oxygen. However, if the car is well sealed and people are in poor health, they may feel bored and tired inadvertently after a long time.
When you get off the bus for a long time and feel the fresh air, this situation is actually telling about lack of oxygen. If the temperature is just right and there is no need to turn on the air conditioner at high speed, there are two ventilation methods.
As long as it is in external circulation mode and naturally ventilated, there is no need to turn on anything. Because the design of the car requires a certain air flow when the car is driving, in order to maintain the most basic ventilation in the car. However, when the car stops, there is no air flow.
The carbon dioxide concentration of inhaled air is only 0.03%, while that of exhaled gas is as high as 4%. Although the loss of oxygen is very small, in theory, there will be no "flat high reaction" because of the decrease of oxygen concentration. However, the higher the concentration of carbon dioxide, the lower the proportion of oxygen inhaled into the air, so although the gas itself is not toxic, too high a concentration will also bring serious problems.
Driving itself has no high-intensity physical exertion, but driving for two or three hours will make you feel tired; The state is basically a little dizzy, mainly due to the lack of oxygen due to the long circulation time in the body, which leads to the decrease of oxygen concentration in the inhaled air. Therefore, the internal circulation should not be used for a long time, and the external circulation is recommended for long-distance driving unless there are two special circumstances.