PREVALENCE OF RESPIRATORY AND HYPERREACTIVITY SYMPTOMS IN RELATION TOLEVELS OF CRITERIA AIR-POLLUTANTS IN SWEDEN

Our knowledge of the adverse health effects from exposure to low level s of air pollution is still insufficient. Early indicators, such as re spiratory symptoms, need more attention. We made use of the fact that possible weak effects can be detected more easily when the relevant ex posure and other determinants are well controlled. A postal questionna ire was sent to random samples of inhabitants registered as residing i n the Vicinity of 55 centrally located air quality monitoring stations in Swedish towns. There were 6,109 questionnaires (76%) returned. Mul tivariate analyses with confounding control were used to examine the e ffects of different levels of criteria pollutants on the prevalence of symptoms. The ranges of the half year values were 9-32 and 2-16 mu g/ m(3) for nitrogen dioxide and sulphur dioxide respectively. Logistic r egression analyses showed higher risks for respiratory problems such a s coughs, throat irritation and nose irritation among the persons most exposed, The associations were most obvious for nitrogen dioxide expo sure among women. The suggested effects of air pollution exposure cann ot be medically evaluated today but they are nevertheless interesting since they are found within common levels usually considered to be saf e.