Word on Air Conditioners Blows a Bit of Hot and Cold

Claims that link air conditioning with illness have become more numerous and widely publicized in recent years. Some airline passengers and attendants, confined during long flights, suspect that on-board air-conditioning systems spread illness; many office workers complain of frequent colds, headaches and other ailments that they attribute to air conditioning. But is air conditioning a health menace?

According to Orange County medical experts, the health benefits of an air-conditioned environment are demonstrable. Properly maintained air-conditioning systems in homes, offices or automobiles can filter air and improve comfort.

Dr. Harold Novey, a professor of medicine at UC Irvine, says a closed environment, such as an office building or a home, can reduce the amount of particulates--large particles--in the air up to 12%. This reduction of airborne particles can benefit allergy and asthma sufferers and make breathing easier and healthier for them.

Hospital surgery rooms, laboratories and electronic-assembly “clean rooms” use air conditioning to filter out bacteria and particles by up to 99%.

One of the most serious incidents linking the spread of illness with air conditioning occurred during a 1976 American Legion convention in Philadelphia. What was later called Legionnaires’ disease was discovered to be the result of bacteria that grew inside hotel air-conditioning systems. Victims fell ill from breathing in the airborne bacteria.

The source, according to the Centers for Disease Control in Atlanta, Ga., was bacteria that grew deep within air-conditioning units where heat, darkness and moisture from condensation provided a perfect growth environment.

A Louisiana state study concluded that up to one-third of all auto air-conditioning systems are contaminated with quick-growing fungi, especially in such hot, humid areas as Louisiana. Breathing in spores from this kind of contamination can cause many different reactions, including illness.

But the operative word in that study’s conclusion is humidity . Dr. Sherwin Gillman, an allergist and staff physician for St. Joseph Hospital in Orange, says: “In order for mold or fungi to flourish, there has to be a stagnant pooling of water and the presence of organic debris. In Orange County and in the Southwest generally, there is little problem with this kind of mold being circulated through air-conditioning systems. The weather here tends to be dry, not humid, and this dryness discourages mold growth.”

But what about the health hazards associated with airline travel? According to Bill Moore, a spokesman for Continental Airlines in Los Angeles, a complete air-volume change occurs inside a commercial aircraft’s cabin every three minutes. Fresh air from outside is drawn into the aircraft cabin through inlet ducts at the center and aft of the cabin. The fresh air is diffused and circulated through the passenger compartment. It is then drawn out through vents at the cabin’s floor level and exhausted through an outflow valve in the cargo compartment.

“The air one breathes in the passenger compartment of a commercial aircraft is probably better than the air we breathe at ground level, says Don Collier of the Air Transport Assn. in Washington. “At 35,000 feet, there are fewer particulates and pollutants.”

Air-conditioning mechanics say that properly maintained air-conditioning units will enhance comfort and reduce health hazards. The simplest thing an individual can do to properly maintain an air-conditioning unit is change its air filters regularly.