The effects of reduced ventilation on indoor air quality in an office building

Abstract

Indoor air quality was monitored at an office building in San Francisco, CA where occupants had registered eye, nose and throat irritation complaints. Portable air pollution monitoring equipment was placed on site to monitor air outdoors and at three indoor sites (a waiting room, an interview room and an office room), and data were taken under two different ventilation rates. The parameters measured were outside air flow rates, temperature, relative humidity, odor perception, microbial burden, particulate mass, formaldehyde and other organics, carbon dioxide, carbon monoxide and nitrogen dioxide. Carbon dioxide concentrations increased as the ventilation rate decreased; odor perceptibility increased slightly at the lowest ventilation rate, and other pollutants generally showed very low concentrations, which increased when ventilation was reduced. In no case, however, did levels exceed current health standards for outdoor air, nor was any one contaminant found to be responsible for the medical symptoms reported by occupants. It is possible that a synergistic effect of the various contaminants and environmental conditions may account for the discomfort of occupants.