What Causes the Odor When the Car Air Conditioner is Turned On?

[MacLayla]

The reason for the odor when the car air conditioner is turned on is: the air conditioning ventilation ducts are too dirty or the air filter is too dirty. The air conditioning system is a part of the car where bacteria and mold tend to accumulate. The mold is blown directly into the car through the air vents, polluting the indoor air and affecting the human respiratory tract. Methods to remove the odor from the car air conditioner include: 1. If the air conditioner has not been used for a long time and only has dust on the panel and vents, a simple wipe is sufficient; 2. If the air conditioner has been used for a long time and cannot be cleaned simply by yourself, contact the after-sales service for timely cleaning of the air conditioner.

[Felix]

When I repair cars, I often encounter air conditioning odor issues. The cause is usually that the cabin air filter is clogged with dust and mold, especially during humid seasons when bacteria thrive more easily. Residual moisture on the evaporator also becomes a breeding ground for bacteria, emitting that musty or moldy smell. Poor parking habits can worsen the problem, such as turning off the engine without switching off the fan, allowing moisture to accumulate. It's recommended to turn off the AC a few minutes before parking but keep the fan running to dry out the system. Check the filter—replace or clean it promptly if dirty, and service it every six months. If the odor is severe, visit a repair shop for professional disinfectant cleaning of the evaporator and air ducts. Otherwise, it's not just unpleasant but could also affect respiratory health. Maintaining these habits can save a lot of trouble.

[PaigeMarie]

My car's air conditioner always emits a strange odor when turned on, which is found to be caused by a moldy or excessively dusty filter; high humidity can lead to moisture accumulation on the evaporator, promoting bacterial growth. I've also heard that the air intake might be blocked, such as by fallen leaves or small animal carcasses, though this is less common. Handling it myself is quite simple: first, pull out the filter to see if it's dirty, and replacing it with a new one usually helps; remember to let the fan run for a few minutes after turning off the AC when parking to reduce moisture retention. If the smell persists, it's advisable to visit a 4S shop for a thorough cleaning to avoid inhaling harmful substances that could harm your health. Developing a habit of regularly checking the filter makes a big difference.

[VonDominic]

From a health perspective, the odor in car air conditioning is often caused by harmful gases produced by mold or bacteria, originating from accumulated dust in the filter or moisture retention in the evaporator. This can trigger allergies or respiratory discomfort. I recommend checking and replacing the filter every season, and using disinfectant sprays to clean the ventilation system when necessary. Turning on the fan for a few minutes before parking to evaporate residual moisture can prevent bacterial growth. If the odor recurs, professional maintenance should be performed to ensure air quality safety.