DAILY AIR-POLLUTION LEVELS AND ACUTE ASTHMA IN SOUTHERN SWEDEN

This study aimed to investigate the association between daily air poll ution levels and the occurrence of acute respiratory signs and symptom s among people with asthma or asthma-like problems. Thirty eight subje cts in the southern Swedish city of Landskrona kept a daily diary for 10 weeks. The daily prevalence of symptoms, supplementary bronchodilat or use and peak how deviations were compared with measurements of envi ronmental nitrogen dioxide (NO2), sulphur dioxide, temperature and hum idity in the city. The occurrence of severe asthma, both during the da y and during the evening, was significantly positively associated with the concurrent 24 h average concentration of NO2, which never exceede d 72 mu g.m(-3). A correlation of borderline significance was found be tween the use of on-demand medication and the NO2 level. However, peak flow deviations were not associated with air pollution or weather con ditions, which may be explained by the beneficial effect of bronchodil ators used by 28 of the subjects, The results of this study confirm th ose of some earlier studies and suggest that aggravation of asthma is related to daily variations in air quality, as indicated by relatively low ambient concentrations of nitrogen dioxide. These results also in dicate that it may be appropriate to examine severe asthma symptoms se parately.