Why is the smell in the car so strong in winter?

The reasons for the strong unpleasant smell in a car during winter may include the following:
Long-term accumulation of air conditioning pipes and filters: During the operation of a car's air conditioning system, the filters will absorb dust and odors from the air. If not cleaned and replaced for a long time, it will produce an unpleasant smell. At the same time, dirt and bacteria inside the air conditioning pipes can also produce unpleasant odors.
Anti-slip materials for car seats and carpets: The anti-slip materials for car seats and carpets can absorb dust and odors during use. If they are not cleaned and maintained regularly, they will produce smells.
Smoking in a car: If someone smokes in a car, the tobacco smoke will spread and adhere to various parts of the vehicle, thus generating a strange smell.
Poor air circulation: In winter, due to the significant temperature difference between the inside and outside of the vehicle, the Windows are often closed, resulting in poor air circulation inside the car and the generation of unpleasant odors.
To solve these problems, the following measures can be taken:
Regular cleaning and replacement of air conditioning filters: Regular cleaning and replacement of air conditioning filters can prevent the occurrence of unpleasant odors.
Regular cleaning of seats and carpets: Regular cleaning of seats and carpets can remove dust and odors.
No smoking in the vehicle: Not smoking in the vehicle can prevent the generation of tobacco smoke.
Regularly open Windows for ventilation: Regularly opening Windows for ventilation can ensure the air circulation inside the vehicle and prevent the occurrence of unpleasant odors.