Automotive interiors extensively utilize materials such as plastics, rubber, fabrics, paint coatings, insulation materials, and adhesives. These materials contain organic solvents, additives, and other components (including benzene, toluene, xylene, ethylbenzene, styrene, formaldehyde, acetaldehyde, and acrolein) that gradually release into the cabin environment during vehicle use, contributing to interior odors—particularly severe in new cars. Below are the related causes: 1. Damp Air Conditioning System: Condensation from rain, snow, or fog combines with airborne dust and adheres to the evaporator surface. The dark, damp corners of the AC system become breeding grounds for mold. Over time, turning on the AC releases a persistent musty odor. Neglecting regular AC system cleaning exacerbates the issue, producing an unpleasant sour or rotten smell when the AC is activated. 2. Decaying Matter in Hidden Areas: Forgotten fruit peels, sweets, or spilled beverages in cabin corners can rot and mold. Wet seats or carpets from leaks or rain also encourage mold growth. Shoes left unused in the trunk or unwashed clothes further emit foul odors. When the AC operates, these odors circulate and spread throughout the cabin. 3. Driving Habits: Individual habits extend beyond driving style and influence cabin odor. Eating, smoking, or cluttering the interior with items over time leads to natural odor buildup. Additionally, parking the car long-term in harsh environments—such as under direct sunlight, in shaded areas, or near garbage—aggravates odor development.
