There is debate and some controversy over sampling for airborne microbes. Many facility managers, when they have a problem, expect a Columbus duct cleaning investigator to come in and immediately start sampling to come up with the specific cause of the problem, then proceed with a solution. Unfortunately, things are not that simple. Many, if not most, reputable IAQ investigators will shy away from in-depth sampling, and with good reason. There are simple, inexpensive sampling programs that will generally verify suspected contaminants and ventilation effectiveness. However, going beyond this to investigate the presence of non-visible mold or fungi organisms can stir debate, as well as the exact methods to sample for such organisms. While sampling for airborne microorganisms is not difficult to do, results are often inconclusive.

A method that involves a sampling strip resembling a Band-Aid adhesive bandage, with the pad on one end used to find the mold. This pad contains a growth media for a wide range of organisms. The strip is activated by the inspector, and a one-sq.in of HVAC duct (or selected building surface) is wiped with the pad. Two strips, each containing a different growth media, are used at each location. These strips are placed in a sterile envelope, which are then returned to the laboratory for incubation and analysis.

A report is returned to the client with the results reported in colony counts /sq. in and on a six-step "severity index" ranging from very low to severe. But experience shows that airborne sampling is not always helpful in identifying the cause of sick building syndrome. For one thing, airborne spores are generally only present in large quantities for short periods of time. Spores being released into the air are dependent on the growing conditions surrounding the organism. If growing conditions are intermittent, as is often the case in HVAC systems, then the release of spores is also intermittent. Only if airborne sampling occurs during the time that spores are being released will significant levels of airborne microbial organisms be found. Surface sampling for microbial contamination, however, can be useful in providing a historical reference of previous growth, and also indicating the potential for future growth. In buildings where high levels of surface microbial contamination have been found, the cleaning and sanitizing of the offending HVAC system or building surface has reduced or eliminated the sick building syndrome personnel complaints. Because of the cost and time requirements, identification of species is not normally recommend by Columbus duct cleaning experts.