By Bob Baker

The above is an opinion occasionally voiced by professionals in the HVAC and IAQ industries. Yet, many facility managers routinely utilize antimicrobial products as part of their maintenance strategy and the demand for such products is constantly growing. This is because more and more indoor contamination problems are being identified as associated with uncontrolled microbial growth. Technicians view visible growth as an immediate threat and want to eliminate it as soon as possible. They see antimicrobial products in various forms as an important part of their strategy for controlling such growths.

To a great extent, the growth of various strains of microbes is a normal part of nature. Although significant visible growths are more frequently observed outdoors, visible growth in the indoor environment is not unusual, especially in showers and other humid locations. Often, these grow to the point where they cause IAQ and other problems. Are the numbers of indoor contamination problems associated with excessive growth on the increase? We do not really know. On one hand, written evidence in the number of popular and trade press as well as peer reviewed articles published has been far more evident since the beginning of the 90's than previously. It could be argued, however, that all mentions of indoor environment matters have increased greatly in frequency and number. I am unaware of any study that has attempted to quantify this. It may be interesting if we had a compilation of articles by subject over time. Such a study would not put the question to rest, as other factors such as better awareness of these issues could be as possible an explanation as any real growth in numbers of occurrences.

In the last analysis, it may not be important to know whether contamination related to microbial growth is a problem on the increase. It is sufficient to acknowledge that uncontrolled growth is a sizeable problem and fixes are needed. Few would dispute that assertion. The real question is how do we approach the problem? Those who oppose the use of antimicrobials urge improvements in system design, instillation and maintenance plus the removal of the dirt and water that are needed to support growth as the preferred techniques for control. These are all good and necessary. However, they are not always enough. Bacteria and fungi require very little of either organic material or water to support high levels of growth under the right conditions. The right conditions are often present regardless of system design, operation or maintenance practices.

It is well established that cleaning and disinfecting of building interiors using appropriate techniques and products, according to label directions will reduce the level of indoor contaminates including airborne dust, total VOC, bacteria, and fungi. Summary results of one study are shown in Table "a". That study, sponsored by the U.S. Environmental Protection Agency (EPA), conducted in a day care center, reported that improved housekeeping reduced total fungi by 61%, airborne dust by 52%, volatile organic compounds by 49% and total bacteria by 40%. What this means is that frequent cleaning with products such as cleaners and disinfectants significantly reduces contaminants in the indoor environment. Furthermore, a study of the use of disinfectants in day care showed that proper and consistent use of disinfectants resulted in a 24% reduction in children's overall infections and a 37% decrease in respiratory illnesses.

Air Pollutant Category	Routine Housekeeping	Improved Housekeeping
Airborne Dust Burdens	11.9 µg/m3	5.7 µg/m3
Total VOC	324 µg/m3	166 µg/m3
Total Bacteria	395 CFU/m3	237 CFU/m3
Total Fungi	127 CFU/m3	50 CFU/m3

Table a - Effects of Cleaning on Indoor Air

Cleaning and disinfecting are activities with a clear positive balance between risk and benefit. Why then does a negative perception about antimicrobial use in HVAC applications persist? That is a difficult question to answer. Most of the reasons that are commonly given simply have no basis in fact (see Table "b"). It is possible that this negative "mindset" about antimicrobials is a holdover from the early days of IAQ science. The earliest theories about building air problems revolved around the possibility that mixtures of chemicals were producing the symptoms reported. Improvement strategies centered on identifying potentially toxic substances that could be reduced or removed entirely from building interiors. During the 90's we have grown to realize that contamination is a much more complex subject. Although there are certainly cases where chemical spills or releases are the obvious cause of a problem, many inter-related factors cause most problem situations.

Reason Given	Available Facts
Too Toxic	Calculations suggest very low toxicity. Research needed.
May Promote Growth	Invalid theory. No scientific basis.
Super Bugs	Confused with "antibiotic resistance". Antimicrobial resistance has never been shown scientifically.
Not Effective	Manufacturer data does not support. Independent verification may be needed.
Chemicals are bad	Everything in the universe is composed of chemicals. Chemicals are neither good nor bad. Concentrations and combinations are what are important.
Better Alternatives Available	Eliminate water/Clean - Good in theory. Not always possible to attain. Only partial solutions.

Table b - Arguments against using Antimicrobials

What is clear is that failure to address problem microbial growth considering all source control alternatives in a balanced manner is not productive. Open and dispassionate discussion of antimicrobial use issues would identify research that is needed to bring out the facts. The resulting data would allow for better directions from manufacturers to guide users in the most productive and responsible use of products. Higher risk products and techniques could be clearly identified and eliminated. Use of those with a favorable benefit/risk balance could be encouraged. Objective guidance could be formulated for potential users. Most in our industry are confused. Confusion leads to indecision and paralysis. Better data would be a key to addressing the confusion and inaction that currently grips users, regulators, and the industry at large.

Our objective should be to work toward guidelines that define the risks and benefits of available strategies for controlling growth. Those guidelines can be formulated when there is an open process that utilizes ongoing dialogue. The American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) has begun a process that could eventually result in clear and reasonable guidance. The Environmental Health Committee will consider moving that process to the next stage during its 1999 fall meeting. They will look at establishing a group of knowledgeable individuals to study antimicrobial use issues and develop recommendations.

That is progress.

Mr. Baker's field of expertise is the control of contamination in air-conditioning and ventilating systems by mold, mildew and bacteria. He writes and speaks frequently about the efficacy, legal risks, and regulatory issues involved in various control strategies. He serves on ASHRAE Technical Committee TC 2.3, TC 2.4, TC 9.8, and Sampling of Airborne Particulate Concentration in Commercial and Residential Buildings GPC 17P. He also serves as a member of ASTM D22.06 (Indoor Air Quality) and is on the Board of Directors of the Indoor Air Quality Association and the Florida Public Health Foundation. Because HVAC applications encompass new uses from an U.S. EPA regulatory standpoint, Mr. Baker works closely with the EPA and industry groups, including serving as the chair of the IAQ committee of the Consumer Specialty Products Association, to help formulate policy in this area.

Bob Baker is Chairman and CEO of BBJ Environmental Solutions, Inc., a company specializing in providing clean air through environmentally responsible products, such as BBJ MicroBiocide , BBJ Micro Coil Clean , "FreshDuct Odor Eliminator ", and BBJ Mold and Mildew Remover™ as well as the revolutionary new Power Coil Clean™. For additional information, Mr. Baker can be reached at (800) 889-2251 or through the company web site at http://www.bbjenviro.com.