Liability concerns underscore the need to address IAQ issues.

A recent increase in the number of workers' compensation claims arising from "sick" buildings has prompted insurers, building managers, owners and risk managers to reassess efforts in addressing indoor air quality (IAQ) issues.

Lawsuits have begun to proliferate where plaintiffs have made damage claims for personal injuries and loss of earnings, citing IAQ problems as contributing factors. Personal injuries have included allergies and multiple chemical sensitivity (MCS) - even though the American Medical Association, in 1991, concluded that MCS "should not be considered a recognized clinical syndrome."

Recently, a judge in California ruled that the HVAC system could be considered a product, and if the jury was to find it a defective product, the strict liability theory could then be applied under product liability law. Therefore, anyone in the chain of design, manufacture, installation and insurance, could be held liable for the injuries suffered.

Yet, the expense of IAQ issues can go even further than that associated with liability. The problem of employee and tenant complaints can manifest itself through cost in health, morale and actual expense to the business involved. Studies have shown that a one percent increase in worker productivity justifies a 15 percent increase in the building construction, or almost a 100 percent increase in the operating costs.

Of course, IAQ issues are not easily solved. Indoor air problems have been related directly to construction techniques undertaken in the wake of energy conservation efforts during the 1970s. Prior to the oil embargo of 1973, ventilation rates were designed to supply fresh air at a rate of 15 cubic feet per minute (cfm) per person, but subsequent conservation measures lowered this to 5 cfm per person. In addition, many new buildings were constructed with sealed windows to keep heating costs down. The issue of fresh outdoor air, coupled with the popularity of variable air volume (VAV) air conditioning systems, helped stimulate current IAQ-related complaints.

Three main causes of poor indoor air quality include: external contamination being brought into the building; internal contamination of the area; and inadequate ventilation. The National Institute for Occupational Safety and Health (NIOSH) has concluded that 53 percent of all sick building syndrome related complaints are the specific result of inadequate or contaminated HVAC systems. Ventilation also affects the circulation of outside and inside contamination. Hence, ventilation is by far the most common cause of sick building syndrome and building-related illnesses.

In efforts to address IAQ problems, investigation should use a multi-disciplined approach, involving experts in occupational health, nurses, industrial hygienists, safety professional, health physicists, engineers, physicians, facilities managers and/or human resource staff.

The first step in an IAQ assessment is to document employee complaints. This will accomplish two tasks: it will allow targeting of problem areas, and will assure those employees who are experiencing symptoms that management is aware of the problem and is trying to remedy the situation.

Some employers rely on information collected by the human resource department, rather than a questionnaire sent to all employees, to minimize the potential for psychogenic illness. Employee interviews may be a logical next step, depending on what the information gathered reveals.

A description of the building and its history should be developed (especially if there has been recent renovation or remodeling), and a walk-through performed. Visual inspections of the problem areas and a thorough examination and balancing of the HVAC system may reveal the source of any problem. Inspectors should take note of any microbial growth in or around the system. Air and water sampling should be performed only if no other explanation of the source complaints has been uncovered. Except in the very few cases, where the contaminant is a single source, this will not usually prove to be helpful. An industrial hygienist would be an asset to the investigation at this point.

Sampling for carbon dioxide, however, can be a useful tool. High levels of CO2 tend to indicate that not enough fresh air is being supplied to the occupied spaces. The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) has suggested that CO2 be used as a surrogate for IAQ because it is present in measurable levels, can be measured easily, directly and quickly, and is directly related to the occupancy of the area.

It is very important to check the HVAC system to ascertain that it is operated to at least the current ASHRAE standard and design specifications. When there is a concentrated source pollutant, either additional ventilation or localized exhaust systems should be in use.

The amount of air reaching a particular work area should also be checked. If there is a stagnant section, rearrangement of the area, redesign of the distribution system, or a boost in the HVAC supply to that area should be provided.

If the problem does turn out to be from a single source, removal of that contaminated source would alleviate the irritation. If the source is a substance that is commonly used in the business, and no other replacement can be found, local exhaust ventilation with the exhaust vented to the outdoors will control the exposure.

Some companies have opted for making their buildings "no smoking zones." This immediately eliminates one of the prime sources of indoor air pollution. Where specific problems are identified, and they are concentrated in either a building or section of a building, the option exists for air purification and filtering systems to be employed. Some of these technologies are highly advanced and can be expensive. They need to be specifically tailored, and are not a standard solution.

If building managers, occupants, management, personnel and any other concerned parties, fully understand the causes and effects of poor IAQ, they can work together to diminish problems and exposures. This will involve source reduction where feasible, maintenance of HVAC systems to optimal design specifications, and other activities that will maintain the quality of the indoor environment.