Magazine article Occupational Hazards

Indoor Air Quality: A Modern-Day Dilemma

Magazine article Occupational Hazards

Indoor Air Quality: A Modern-Day Dilemma

Article excerpt

For those practicing in the health, safety, and environmental arena, hardly a day goes by without some announcement related to indoor air quality (IAQ). While there is little doubt that poor IAQ can be a real problem, there are difficult questions with regard to how important this problem is relative to other occupational and environmental health concerns.

In terms of assessing and solving indoor air problems, IAQ frequently has been a quagmire for the safety and health professional as well as the environmental regulator. Problems include a seemingly double standard for the application of exposure limits, the use of an indicator of pollution rather than the "real thing," radon hype, and the uncharted waters of indoor aerobiology. In this article, I will share my experiences, opinions, and biases on IAQ with a concentration on problem areas.

When the Problem Started

As a consequence of the energy crisis of the 1970s, commercial and some residential construction techniques have been changed to increase the energy efficiency of heating, ventilation, and air conditioning (HVAC) systems. This has included such measures as sealed windows, reduced outside makeup air, and other techniques to decrease outside air infiltration. Existing structures have also been "buttoned up."

While these changes are of benefit from an energy and cost-savings standpoint, research has demonstrated that adverse health problems can arise from the recirculation and subsequent concentration of air contaminants and bioeffluents. In addition, the use of variable air volume HVAC systems in large commercial buildings can result in significantly reduced air exchange rates in certain interior zones. This may cause occupants to sense a staleness in their environment.

Other factors common to the "sick building" phenomenon include:

* Intake of contaminated makeup air;

* Offgassing of new furniture, wall coverings, or carpeting;

* Humidification systems or liquid reservoirs resulting in the spread of microbial contamination;

* The buildup of organics and ozone in poorly exhausted areas where reproduction or other office equipment is located.

Employee complaints relating to indoor air pollutants can range from dizziness to burning eyes and upper respiratory distress. These "tight building syndrome" complaints can be the result of mass hysteria of psychosomatic origins, stress, personal allergies or sensitivities, or actual adverse exposures to chemical, physical, or biological agents.

Typical evaluation schemes can include measures of indoor air quality such as temperature and humidity, bioeffluents (carbon dioxide), particulate (dust) levels, organic and inorganic contaminants, and the types and levels of specific microbes.

Temperature and humidity are very important measures of IAQ since they directly influence the perceptions of the occupant as to comfort and health. This is especially true for temperature, but humidity control is also very important for both perception and health. Humidity levels that are too low can result in buildup of static electricity, complaints of eye and throat irritation, dry skin, and other problems. High humidity levels can result in equipment corrosion and microbial growth problems.

Dirty ventilators suggest sampling for respirable or total particulates, although these tend to be very low in most office environments. Asbestos and fiberglass may also need to be included in some surveys.

Aldehydes, including formaldehyde, are typically evaluated since they are common office contaminants offgassed from furniture, office decorations, carpeting, and other office fixtures. Formaldehyde has received special attention lately because OSHA considers it a potential occupational carcinogen.

Carbon monoxide is an important measure of IAQ because it can be brought into the work environment from the outside air and it is also a byproduct of tobacco smoke. …

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