Do I Work in a Sick Building?

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Indoor Air Quality

Indoor air quality (IAQ) is the subject of much attention these days, and for good reason. There is more and more evidence that the quality of the indoor environment can have profound effects on the health of building occupants. The World Health Organization estimates that up to 30 percent of office buildings worldwide may have significant problems, with 10 to 30 percent of the occupants of the buildings experiencing health effects which are, or are perceived to be, related to poor IAQ. Although serious health problems related to IAQ are rare, the perception of endangered health is increasingly common among building occupants. In the United States, the National Institute for Occupational Safety and Health recently had 3000 telephone calls relating to poor IAQ in a single week, 90 percent requesting investigations of the buildings they occupy or manage.

The causes and consequences of poor IAQ are a long way from being completely understood. It has been the experience of the American Industrial Hygiene Association (AIHA) that building owners, managers, employers and occupants want to know more about the issue than has been provided by the news media, whose stories have generally raised fears without offering solutions. AIHA has developed this information bulletin to provide building owners, managers and occupants with a summary of the current state of knowledge on IAQ. The goal of this bulletin is to inform the reader, so that you can make intelligent decisions about the present condition of your building.

What is good indoor air quality?

Most occupants will agree that indoor air quality is good when it is free of odors and dust, is neither too still nor too drafty, and is a comfortable temperature and humidity. General guidelines for achieving good indoor air quality include:

• Ventilation is in accordance with the guidelines established in the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 62-1989.

• Comfort (temperature, humidity, air movement) factors are acceptable to most occupants.

• Mechanical equipment and building surfaces are maintained in sanitary condition.

• Significant emission sources are isolated from occupied space.

• Major sources of contamination are promptly controlled.

• Operations, maintenance and construction activities are performed in a manner that minimizes occupant exposure to airborne contaminants.

What are common complaints about IAQ?

The most common complaint is related to temperature: the air is either too hot or too cold. The second most common complaint is about air movement: the air is too drafty or too still. Other common comfort-related complaints involve humidity: the air is too dry or too muggy.

Some health-related complaints associated with poor air quality mimic those of the flu or a cold: headaches, sinus problems, congestion, dizziness, nausea, fatigue, and irritation of the eyes, nose or throat. Such symptoms are often difficult to associate with the workplace. The indoor environment is usually not the suspected cause of occupant symptoms unless the symptoms are shared by a number of occupants; found to be unreasonably persistent; or there is a distinct and suspect quality to the air.

Health-related complaints may be due to allergic reactions. In the presence of an allergen, 10 percent or more of a given population may exhibit symptoms including sneezing, swollen airways, and asthma-like attacks. Individuals with a building-related allergy will experience similar symptoms in other environments if the particular allergen is present (for example, dust mites, cat dander or mold spores).

When are IAQ complaints most likely?

Factors associated with an increased likelihood of complaints include new furnishings, uncontrolled renovation activities, poor air circulation, and persistent moisture. Complaints are also more likely when there is a stressful work environment, such as impending layoffs, a great deal of overtime, or an ongoing employee/employer conflict.

What are common sources of IAQ problems?

Contaminants may originate from a variety of sources inside or outside of a building. Airborne chemicals, bacteria, fungi, pollen, and dust may all contribute to the problem, as well as non-air quality factors such as temperature, humidity, lighting, noise, personal and work-related stress, and pre-existing health conditions.

Potential sources of contaminants in office buildings include tobacco smoke; dust; poor maintenance of heating, ventilation and air-conditioning (HVAC) systems; cleaning supplies; pesticides; building materials; furnishings; occupant metabolic wastes (respiration and perspiration); and cosmetics. Of course, virtually all of these are present to some degree in every building. They cause serious IAQ problems only when concentrations become excessive.

Dusty surfaces, stagnant water and damp materials provide an environment ripe for microbial growth. When mold spores and other microbial particles become airborne, some building occupants may experience allergic reactions. One potential, but extremely rare, infection is caused by Legionella bacteria.

Cigarette smoke contains carbon monoxide, formaldehyde and thousands of other chemicals. It presents a serious health risk to those exposed. Recent studies have shown that exposure to secondhand tobacco smoke may result in inner ear infections, asthma and lung cancer in nonsmokers. The EPA has listed tobacco smoke as a confirmed cancer-causing agent.

Contaminants may also originate outside the building and enter via the outdoor air intakes or, when more air is removed by the HVAC system from the building than is supplied, by flowing into the building through any available gap.

Why is ventilation important?

Poor IAQ occurs when ventilation is inadequate in keeping contaminant concentrations at levels that do not produce occupant health problems. The HVAC system must not only control contaminants, it must provide a comfortable environment. The perception of still or stale air, odor, draftiness, or errant temperature and humidity leads to discomfort; and discomfort, however subtle, can be the beginning of IAQ complaints. In general, IAQ complaints originate with the HVAC system failing to meet occupant needs. Of the more than 1200 IAQ investigations performed in recent years by the National Institute for Occupational Safety and Health (NIOSH), over half were attributed to inadequate ventilation.

What can be done about IAQ complaints?

First, either through interviews or by questionnaire, determine:

• What are the specific complaints?

• Where in the building are similar concerns about IAQ occurring?

• When does the problem occur?

• When and where did it first occur?

• Who is affected?

• What health effects are occupants experiencing?

• Do the health effects cease soon after leaving the building?

• Have those affected seen a physician and, if so, what were the diagnoses?

• Is there any environmental condition (e.g., weather) or activity (e.g., remodeling, use of the photocopier, spraying of pesticides) inside or outside the building associated with occurrence of the problem?

• Has the building engineer or HVAC contractor evaluated the area(s) and, if so, what were their conclusions?

Second, evaluate the information. Determine if there is a time or space pattern to the complaints. Also, consider whether the problem may be linked with an activity or condition inside or outside the building, or a malfunctioning HVAC system. In many cases the source of the complaints may be readily apparent with a little investigation, such as HVAC system air intakes next to the loading dock, the recent addition of four large photocopiers in a small room without ventilation system modification, an incorrectly set or broken thermostat, or recent remodeling.

When should air testing be done?

Carbon dioxide testing is often performed during the early stages of an IAQ investigation. In general, if carbon dioxide levels are routinely found to approach or exceed 800 to 1000 parts per million during the course of a work day, then the HVAC system may not be providing enough outdoor air to occupied spaces. When sufficient outdoor air is supplied to keep carbon dioxide levels well below 800 to 1000 parts per million, the ventilation is generally considered to be adequate. It should be emphasized that carbon dioxide is not the "culprit" in IAQ problems; it is a normal product of the our breathing. Elevated carbon dioxide concentrations in a building reflect insufficient exchange of "fresh" outdoor air for "spent" interior air, allowing the accumulation of other contaminants.

It should also be emphasized that this approach does not work in all cases. If a particularly irritating or toxic contaminant is present, the problem can only be resolved through control of the contaminant at its source.

Testing for other contaminants (e.g., particulates, volatile organic compounds, microbes, formaldehyde and pesticides) may provide valuable information but is recommended only if there is good reason to believe that contaminant is present (a source has been identified, or medical evaluation of occupants so indicates). "Shotgun" air testing for a broad spectrum of potential contaminants is generally misleading and seldom helps to identify a problem.

Even when standards or guidelines have been established, as they have for occupational exposure to more than 600 chemicals, they have been developed for exposure to individual chemicals in an industrial setting and not the complex contaminant "soup" often found in office building air. In addition, the standards have been developed for men without pre-existing health problems, not for the diverse population typically found in office buildings. In summary, it is usually very difficult to use the findings of air testing to draw conclusions about the degree of health risk to which occupants are exposed.

The greatest value of air testing is in the comparison of the results of testing in different locations or at different times. The data generated often yield very valuable information about the origin of the problem and possible solutions.

How can IAQ problems be prevented?

Three fundamental measures that will greatly reduce the likelihood of IAQ problems are: (1) good building design, (2) effective building maintenance (particularly of the HVAC system), and (3) intelligently designed and executed remodeling projects. It is recommended that every building manager develop a performance profile of the building ventilation system, including analyses of comfort, ventilation and sanitation. This is accomplished by:

• Inspecting accessible areas of the system for obvious malfunction, bad design or contamination; and

• Determining airflow, temperature, humidity, carbon dioxide concentrations, and air balance (pressure differentials) in representative areas (zones or rooms) of the building.

The information developed:

• May reveal problems with the building's HVAC system, that is, areas in which the system is clearly not performing on par with the remainder of the building; and

• Allows comparison with building design parameters, building codes and guidelines established in the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 62-1989.

Beyond the initial system profile, it is crucial that the HVAC system be routinely inspected and maintained.

Maintaining good IAQ in a building also requires careful managing of custodial, pest control and building engineering or contractor maintenance activities.

Prior to initiating remodeling activities, discuss IAQ concerns with architects and contractors. Require that the materials and procedures used minimize airborne contaminants. Where feasible, schedule work to minimize the impact on air quality (e.g., perform painting on weekends) and arrange for the ventilation system serving the area to be isolated from the remainder of the HVAC system. If walls are being added or moved in the project area, or the number or distribution of occupants is to be greatly changed, modify the ventilation system to meet the new requirements.

What can be done to control indoor air contaminants?

The best method to control indoor air contaminants depends on the source or sources causing the complaints. Source control is generally the most cost-effective solution to the problem. For example, environmental tobacco smoke-related complaints can be eliminated by prohibiting smoking within the building, or by isolating designated smoking areas and providing them with independent ventilation.

Modification of the ventilation system may also be an effective method of resolving IAQ complaints. Contaminants can be diluted with outdoor air, or contaminants such as radon can be isolated or removed by changing air pressure relationships between adjoining areas. Increasing the outdoor air supply to meet the criteria of ASHRAE 62-1989 is usually not difficult or prohibitively expensive. The increased cost is often no more than 5 percent of the original annual energy expenditure. The improved work environment more than pays for itself through improved occupant productivity.

Air cleaning may also be used to control indoor air contaminants, particularly when the contaminant source is outside the building. For example, building occupants may experience allergic reactions to pollen drawn into the building with outside air. Typically, air cleaning is performed by an air filtration system and is used in conjunction with source control or other ventilation system changes.

When should I seek outside help?

If the problem persists after you have identified and rectified obvious sources, you may want to seek outside assistance. You may also require outside help if the problem requires immediate and concerted attention and your resources are limited, or your preliminary investigation reveals little of significance and you don't know what to do next.

Specialists in resolving IAQ problems are available from the professions of industrial hygiene and ventilation engineering. In certain cases, assistance from specialists in medicine, lighting, acoustic design or psychology may be needed. Whatever the background, you should be aware that proven professional experience in resolving IAQ problems is crucial. The investigatory skills and perception necessary to solve your problem are only developed from experience, education, and a personal commitment to remain up-to-date in this rapidly evolving field.

Sources of professional help include the yellow pages of the telephone book (under "industrial hygiene" and "engineers-ventilation") or local, state, or federal agencies, such as the local or state health department. For a list of industrial hygiene consultants published semiannually in the American Industrial Hygiene Association Journal, please call AIHA at (703) 849-8888.

When evaluating consultants, pay particular attention to their professional background in terms of education, professional credentials, the reputation of their firm, and, most important, demonstrated success in resolving similar situations. Ask for references. Hiring someone to perform a poorly conceived study is worse than a waste of money and time; it may lead to erroneous conclusions and costly remedial efforts of no intrinsic worth. If a consultant proposes elaborate and expensive air monitoring without demonstrating to your satisfaction that the resulting data will be meaningful, look elsewhere for assistance.

There are also written references that you may find useful. Among these is an EPA/NIOSH publication entitled Building Air Quality-A Guide for Building Owners and Facility Managers. It is available from the U.S. Superintendent of Documents at (202) 783-3238.

In Summary

Indoor air quality concerns are a fact of life for building owners, managers and occupants. It is not possible to satisfy every building occupant at all times. However, it is possible and necessary to provide a work environment that is healthy and safe. A building managed with an eye for preventing IAQ problems may not guarantee that occupants will not complain about IAQ, but it does greatly reduce the likelihood of serious health problems.

AIHA

The American Industrial Hygiene Association is a professional society for persons dedicated to the prevention of workplace-related illness or injury that may affect the health or well-being of workers or the community. With more than 12,000 members, AIHA is the largest international association serving the needs of occupational and environmental health professionals practicing industrial hygiene in industry, government, labor, academic institutions, and independent organizations.

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