NASAL CONGESTION IN RELATION TO LOW AIR EXCHANGE-RATE IN SCHOOLS - EVALUATION BY ACOUSTIC RHINOMETRY

Upper airway symptoms are common, but there is little information avai lable on clinical findings in relation to indoor air pollution. This p ilot study was conducted to test whether increased levels of indoor ai r pollutants in schools may correlate to a swelling of the nasal mucos a. The assumption was made that the degree of swelling could be relate d to the degree of decongestive effect of xylometazoline, and measured by acoustic rhinometry. The study was performed among 15 subjects in a school with low air exchange rate (0.6 air changes/h) and 12 subject s in a school with high air exchange rate (5.2 air changes/h). Hygieni c measurements were performed in both schools. Acoustic rhinometry was performed for each individual under standardized forms. Cross-section al areas and volumes of the nasal cavity were measured before and afte r decongestion with xylometazoline hydrochloride. Absolute values of t he minimal cross-sectional area were lower in the school with poor ven tilation. The decongestive effect of xylometazoline was significantly higher in the school with low air exchange, when correction for the in fluence of age was made. A diminished decongestive effect was seen wit h increasing age. The exposure measurements showed that indoor concent rations of volatile organic compounds, bacteria and moulds were higher in the school with low ventilation. In conclusion, raised levels of i ndoor air pollutants due to inadequate ventilation in schools may affe ct the upper airways and cause a swelling of the nasal mucosa, and aco ustic rhinometry could be a useful objective method to measure human n asal reactions to the indoor environment.