Car Odors May Be Caused by a Fungus
Question: I have a 1986 Toyota Cressida that I bought new. I have noticed from time to time that the air conditioning will have a peculiar odor. It smells like a strong commercial soap or disinfectant. Could there be something the air conditioner is sending into the car that might be harmful to breathe regularly? I have asked the dealer service people, but they say they don’t know.--A.R.
Answer: The air-conditioning system in your Toyota operates by sending a cooled fluid into what is called an evaporator underneath your dashboard. This looks like a radiator and cools air that a fan blows through it.
As the warm, moist air hits the cool surface of the evaporator, water condenses on the surface. After the car is shut off, the water warms up. This cycle continues as you use the air conditioner throughout the spring and summer.
The moisture allows fungus to grow. Fungus is a common microscopic organism that feeds off nutrients in the air. The fungus on the evaporator literally blows through the car. Typically, fungus smells sour. When you say it smells like disinfectant, you are probably associating the smell with a bathroom, where fungus is common.
Fungus can cause severe allergic reactions in certain people. There are many types of fungi, and some are more virulent in causing reactions than others, according to Dr. Howard E. Hagglund, an allergy specialist. Fungus causes all types of organic things to decay. It is also difficult to combat.
Hagglund suggests that you attempt to control the fungus by placing equal parts of vinegar and a chloride bleach in a pan in your car for a couple of hours. You occasionally should turn on the fan to circulate the fumes and allow them to attack the fungus.
Ultimately, you may want to have the evaporator removed and cleaned. Cleaning is not possible while the evaporator is inside the car, but a thorough soaking in a chlorine solution to kill the fungus would give you a clean start. That would not prevent the problem from recurring, however.
If you experience a problem, you should see a doctor. For sensitive people, there are filters that can catch air-blown fungi in homes and portable ones that can be used in a car.
