What is the phenomenon of white smoke from the exhaust pipe in winter?

[MichaelMarie]

White smoke from the exhaust pipe in winter is a normal phenomenon. The reason is that in winter, the temperature is low, and when high-temperature exhaust gas passes through the catalytic converter and muffler, it encounters cold air, resulting in a white appearance due to the heat exchange. The functions of the exhaust pipe are: 1. Reducing environmental pollution: The exhaust pipe contains purification devices that can effectively filter harmful gases from the exhaust; 2. Ventilation and exhaust: The car exhaust pipe operates in a cycle of intake, compression, work, and exhaust—without an exhaust pipe, the car would not function; 3. Noise reduction: The exhaust pipe is equipped with a muffler, which reduces car noise by using multiple channels to divert airflow, causing friction and collisions between the diverted flows to gradually slow down the airflow speed, thereby repeatedly reducing noise.