Air Quality Problems - Not Just Chalk Dust

The authors forecast an increasing problem with indoor air quality as more workers spend more time inside older buildings with deteriorating heating and ventilation systems or in newer air-tight buildings with new chemicals. Health problems associated with poor indoor air quality can be identified at contaminant levels lower than those allowed by OSHA.

Examples of health problems related to poor air quality are asthma, "sick building syndrome," multiple chemical sensitivity, and hypersensitivity pneumonia. Persons with chronic conditions, e.g., connective tissue disorders, immunosuppression, are at greater risk of respiratory symptoms.

"Sick building syndrome" has variable symptoms (eye irritation, dry throat, headache, sinus congestion, cough, nausea, etc.) and resolves with leaving the area/building, but returns upon re-entry.

Multiple chemical sensitivity was reported in about 6% of 4000 surveyed adults in California. While the condition is not clearly defined, some believe that it occurs as a result of effects on the limbic, immune and respiratory systems. Psychological factors influence the onset and severity in some persons and groups; the person typically affected at work has spent long hours over many years in the location.

Hypersensitivity pneumonia is characterized by flu-like symptoms, including fever. The cause is microbes (bacteria, fungi and molds) in humidifiers and poorly maintained heating, cooling and ventilation (HVAC) systems.

Testing of 1200 buildings (including schools) in the 1970-80s found inadequate ventilation (53%), contaminants such as volatile organic compounds released from cleaning agents, fabric dyes and flooring finishes (15%), outdoor air contamination such as pesticides and exhausts entering air intake units (10%), and microbes such as molds and fungi (5%).

Newer energy efficient HVAC systems that reduce the outdoor-indoor air exchange and custodial work involving cleaning product vapors and disturbed dust during work hours add to the problem.

Prevention strategies include:
1) locating air intake units away from pollution sources (e.g. bird droppings on roofs, near traffic exhaust);
2) fresh air intake more than the minimum of 10 cubic feet per minute per person;
3) minimizing moisture in ventilation ducts;
4) humidity control;
5) minimal fabric and carpet which emit organic compounds and collect dust;
6) devices to remove dirt from shoes upon entry;
7) well maintained HVAC system, and
8) careful dusting/vacuuming.

Communication within the organization is also critical to address air quality concerns. If management dismisses reported symptoms as "psychological" and unfounded rather than investigate the complaints, workers will talk among themselves and come to believe a dangerous situation is being covered up; stress will exacerbate symptoms. Open discussion that uncovers the history and pattern of reported problems, including factual and emotional components, provides the basis for proper investigation and remedies.

(Anonymous. The indoor air we breathe: a public health problem of the 90s. Public Health Reports 1998;113(5):398-409)

COMMENT: Many schools have poorly designed and/or maintained ventilation systems and have unrepaired water leaks. These contribute to poor fresh air exchange, relatively high humidity, and fungal growth. Air quality is an appropriate topic for the school health advisory council.