By Bob Baker

What is the relationship between odor and air quality? This is a question that has plagued researchers in the field since the beginning of study of the indoor environment. The human nose is by far the most convenient and readily available air measurement tool we have. Everyone has one. It is also extremely sensitive. The human nose can detect the presence of some substances in concentrations that are so low that even sensitive analytical instruments do not indicate their presence. At the same time noses have limitations. There is considerable variation from person as to both what they report as the strength of a given odor and whether it is acceptable or not. Training of so-called sensory panel members improves the usefulness of odor judgements they provide and odor panels have been used extensively in the research conducted to date. Considerable development work is also being done on "electronic noses". To date these have not yet been able to replace humans.

Harmful Odors

There are a number of odors that are clearly either harmful in and of themselves or normally associated with conditions that could lead to poor IAQ. A prime example would be a highly toxic gas that is accidentally released, generated from a toxic chemical spill, or given off due to faulty operation of an appliance or machine. These gasses are more likely to be found in industrial settings and not in homes or offices. More commonly, we are exposed to foul odors that are associated with excessive microbial growth. These odors are currently being studied by several researchers in an effort to find out if the gasses that produce the odors themselves cause harm or the symptoms reported are due to exposure to the organisms that give them off during growth. We suspect that both hold the potential for harm or at least discomfort. When present, these types of odors should be of concern to the indoor environment professional.

Other Odors

There are, of course, many other odors that are probably harmless. Some of these are seen as pleasant, others may be objectionable. These include cooking odors, fragrances and perfumes, non-toxic chemicals or low quantities of moderately toxic chemicals, body odors (and other human and animal odors), and the many other scents that make up our environment. Most people tolerate these odors well and will not complain about them unless they are unusually strong or persist for a long time. This tolerance is helped by the fact that humans adapt to quite high levels of odor after they have been in an environment for a short time and will not even notice the odor unless someone coming in points it out. This adaptation takes place in as little as five minutes. Thus even objectionable odors may not pose a problem if they are not overly strong or actually toxic. These types of odors would seem to be of little concern.

Non Odor Gases or Particulates

There are many gases that can be present in the indoor environment that are potentially harmful (possibly deadly) and yet do not advertise their presence through a detectable level of odor. These include such things as Carbon monoxide, Radon, and some forms of Methanol. In addition, many harmful particulates such as Asbestos, Bacterial and Fungal Spores, and carbon compounds may be present in harmful quantities yet not have a level of odor that signals their presence. For example, the CDC in Atlanta estimates that between 3,000 and 7,000 persons a year die from causes related to exposure to Legionella which has no odor.

From the above discussion, it is apparent that an indoor environment professional should take aggressive steps to guard against both the non odor producing gases and particulates and the harmful odor producing gases. In achieving the goal of providing a healthful productive indoor environment, eliminating these contaminates should be enough. Reducing or eliminating other odors may be seen as desirable but not essential. This is especially true if budgets are tight (as they always are). Eliminating all odors can be costly.

Legal and Reputation Risk

Unfortunately, HVAC Contractors and other indoor environment professionals often face a greater risk to their reputations and danger of legal problems from common and generally non-harmful odors. This is not because the other sources outlined are not problems. They are. However, as frequently as they occur, their number is nothing compared to the "IAQ Problems" that rise out of non-harmful or minimally harmful odor sources. In a large percentage of IAQ incidents, no health hazard is ever specifically identified. After days or weeks of investigation, the cause remains unidentified and it is unclear whether or not anyone has been injured. That really doesn't matter. If a business, school or office building makes the news because of an IAQ problem or a building is evacuated and people hauled off to hospitals, few will remember or even know that it was all a false alarm. Some of the people involved will still seek legal advice and may bring actions against the building owner, contractors and others. Even if all the actions are eventually thrown out, the cost both financial and to reputations is great.

As big a problem as public building air quality problems are, like problems in private homes are probably even more costly for contractors. If a home air conditioner starts putting off foul odors, or a lot of dust and other particulates, the homeowner is likely to call another contractor to cure the problem. In addition, that same homeowner will tell friends and neighbors what a mess the original contractor made of the system. The reputation of the first contractor will be damaged and they will not even know why.

Preventative maintenance service calls that concentrate on only the mechanics of the system such as motors, refrigerant levels, and contact cleaning are good but not enough. Be sure your technicians leave a clean air handler/furnace and one that is treated to prevent the growth of the mold and bacteria that are the cause of many objectionable odors that result in the majority of IAQ problems. Foul odors may not always mean that there is a serious health threat. They do, however, almost always serve as a negative for the occupants of the space and often trigger complaints that lead to a claim that the building is sick. Preventing objectionable odors should be a major priority for your service operation.

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.