Nothing beats the cool air-conditioning of your car during a warm day, but have you noticed that there are actually two modes that you can toggle inside your car, with one bringing in fresh air and the latter circulating the air inside your car.
Fresh air mode
With an image of an arrow going inside a car from the outside representing it, this mode brings in fresh air from the outside through your air-conditioning, which is helpful when your car has been parked in the sun or unmoved for a period of time as it can flush out the stagnant and hot air. The downside to it is that any outside gases and particles such as exhaust fumes and dust can get inside your car and make you uncomfortable.
Air recirculation mode
Seen with an image of an arrow doing a u-turn inside a car, this mode recirculates the air inside your car, which is suitable to keep your car cool as it recirculates the cool air in your car, and prevents anything outside from coming in. The problem is that if there’s any impurities it will stay recirculating inside your car, and if used for an extended period of time you will be breathing in the same air over and over again, which is not good for your body.
Conclusion
In short, when you first enter your car, it’s better to let fresh air in. After a while, you can switch modes to recirculate the air inside your vehicle, but be sure to let fresh air into your vehicle once in a while.
Most cars come with an air recirculation button that when toggled, switches from fresh air mode to air circulation mode. However, modern cars are smart enough to switch modes by themselves without any user intervention.