When twenty percent or more of a building’s occupants complain of these conditions, it is said that these individuals may be suffering from sick building syndrome (Akovali, 2007).
Sick building syndrome is described as a condition wherein a group of people in the same building or similar structure experiences acute health symptoms which improves or disappears once they go out of the building. These symptoms include headache; irritated eyes, nose, and throat; cough; dry and itchy skin; dizziness and nausea; inability to concentrate; sensitivity to odours; and fatigue. Its underlying cause remains unclear. However most attribute the phenomenon to inadequate building ventilation, contaminants and stress (Fraser, 2008). According to the study by Bischof and Bullinger (1998), symptoms of sick building syndrome were reported on both air-conditioned and naturally-ventilated buildings. However, incidents of SBS were more evident in poorly maintained air-conditioned buildings.
Inadequate building ventilation. At the start of the 20th century, building ventilation standards set the ventilation rate to 15 cubic feet per minute per occupant. However, the oil crisis in the 1970s caused a reduction of ventilation rates to 5 cfm. The reduced flow of outdoor air was discovered to cause discomfort and acute health symptoms among the building’s occupants. In order to minimize energy use and attain an acceptable Indoor Air Quality level, the American National Standards Institute / American Society of Heating, Refrigerating, and Air-Conditioning Engineers had updated its ventilation standard to 20 cfm for office spaces (Environmental Protection Agency, 1991).
Airborne contaminants. Ventilation systems for office buildings usually acquire air from the outside. As outdoor air gets inside the building, it also brings airborne contaminants. Sources of contaminants include motor vehicle fumes, plumbing and building exhausts;