Abstract

Possible relations between incidence and prevalence of sick building syndrome (SBS), indoor exposures, and personal factors were studied in a four year longitudinal study among personnel (n = 129) in six primary schools. The mean concentration of carbon dioxide was above the recommended value of 0.08 microliter/l (800 ppm) in all schools, indicating a poor outdoor air supply. Indoor concentration of volatile hydrocarbon (VOC) was enhanced at high room temperatures. Respirable dust, but not concentration of VOC was enhanced at lower ventilation rates and high air humidity. Chronic SBS was related to VOC, previous wall to wall carpeting in the schools, hyper-reactivity, and psychosocial factors. Incidence of new SBS was related to concentration of respirable dust, current smoking, and the psychosocial climate. Remission of hyperreactivity, decrease in sick leave owing to airway illness, removal of carpeting in the schools, and moving from new to old dwellings resulted in a decrease in SBS score. It is concluded that SBS is of multifactorial origin, related to a variety of factors and exposures. The total concentration of hydrocarbons is a simple and convenient measure of exposure, which also seems to be a predictor of chronic symptoms. Further investigations on the effect of temperature, ventilation, and air humidity on SBS should consider how these factors may influence the chemical composition of the air. Because poor air quality in schools could also affect the children, it may have implications for the state of health of a large proportion of the population.