Is Your Air Conditioner Hazardous to Your Health?

LCT Staff
Posted on November 1, 2000

Did you know that turning on the air conditioner or heater in your vehicle could be hazardous to the health of your chauffeurs and passengers? Research has shown that a vehicle’s evaporator system can be infested with more than a dozen types of fungi that blow through the air vents. In a study of automobile air-conditioning systems and the bacteria they can hold, Robert Simmons, a microbiologist at Georgia State University in Atlanta, and his team dismantled the air- conditioning systems in 32 automobiles, including luxury and economy vehicles. They found more than a dozen types of fungi, mold and bacteria.

Did you also know that an average-sized car’s interior can support more than 10 times the pollutants found in the same volume of space outside the vehicle? These pollutants aren’t just simple dusts and pollens either; they’re the products of bacterial and fungal growth within the damp evaporator core case, the starting point for all air that passes through a car’s ventilation system. If an average-sized car contains this many pollutants, just imagine what your 120-inch stretch limousine might have blowing through its ventilation system. These bacteria and pollutants could not only make your passengers’ ride very uncomfortable, but pose a huge threat to their health as well. At greatest risk are the young, the elderly, those with immune system complications, pregnant women, those susceptible to allergies and those with asthma. “The first thing people get are the classic allergy symptoms,” says Simmons. “Your eyes get itchy, your nose starts running, and you start to sneeze.” A dramatic and extreme case of what can happen, though, is the outbreak of Legionnaire’s Disease in Philadelphia almost 25 years ago. This particular strain was traced to the bacteria-laden air-conditioning system at the hotel where an American Legion troop was staying.

The journey of the air that passes through your vehicle’s system begins at an inlet under the hood and exits at the dash and other interior vents. In this chain, mounted behind the dash is a case that houses the evaporator core, a radiator-like device with tubes of refrigerant that “sweat” as condensation collects on the frigid cooling coils, like a cold glass of water on a hot day. Most water that forms is collected and vented through an outlet in the floor of that case, but there are many spaces and crevices within the case that also hold water yet never dry out. This creates the perfect conditions for the growth of bacteria, mold and fungus. While water collects only during air-conditioning operation, all air that passes through the system passes through this bacteria-infested case, even heating and normal ventilation air. Another problem that arises as contaminants continue to collect is airflow becomes more and more restricted through the evaporator core. You may hear the blower fan motor working harder and feel a reduced output of air from the dash vents. Although this does not pose a health threat, it could cause the fan motor to burn out and result in repair costs.

The solution, of course, is to clean your vehicle’s interior evaporator cases thoroughly and regularly. One option is to bring it to a dealer where a technician will disassemble the dash components and behind-the-dash HVAC hardware to extract the evaporator case, allowing for its disassembly and cleaning. This usually costs several hundred to $1,000 at a dealership. There are also a number of products on the market that allow technicians to clean the evaporator cores without actually disassembling the dash components. These cleaning solutions are injected into the evaporator case to remove mold, mildew and bacteria while deodorizers improve the interior’s smell. DWD2 Evaporator System Cleaner, for example, is a cleansing antibacterial foam that fills the evaporator case fully before returning to liquid form and trailing out the drain hole, taking all the contaminants in the evaporator core with it.

To do this, a 3/16-inch hole is drilled between the evaporator case and the blower fan, where a probe with directional nozzles is permanently installed. With the nozzle probe in place, a flexible plastic hose is then attached to the probe, which is then pressed onto an aerosol can of the DWD2 product. This fills the evaporator case with the foam. The air conditioner is then cycled for about 20 minutes, according to directions. In a recent demonstration of the product, performed on two interior evaporator cases of a 120-inch stretch limousine, DWD2 left the cores clean with no mold, dust or dirt in sight. The air that came out of the vent was stronger and colder by almost 10 degrees. According to the manufacturer, the product also makes the air that is pushed through the system smell cleaner and fresher, and melts nicotine oils that have collected in the system. The delivery system, installation and initial application of a product like DWD2 costs between $80 to $100 at a dealership, and lasts a year or longer. After that, with the apparatus already in place, you can buy an aerosol canister that costs about $40. The manufacturer suggests using a refresher application, which costs $20, between cleanings, as needed.

A similar product on the market is BG Frigi-Fresh, a powerful deodorizer that is said to remove musty odors and add a fresh, clean scent to the automobile’s interior while also killing mold, mildew and other odor-producing organisms that grow in the evaporator core and housing. BG also offers Frigi-Clean, a cleaning solution designed to remove bacteria, mold, spores, fungi, road grime, nicotine oils and debris that accumulate in the vehicle’s air conditioning evaporator. Bacteria in the evaporator case— and the problems that they can cause—have been the subject of research for years. Luckily, this is an easy problem to fix. A simple cleaning of the evaporator core, either by having it dismantled or injected with a cleaning solution at the dealer, can drastically improve air flow and air quality in your vehicles.

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