The current cohort study in the canton of Zurich is investigating respiratory diseases in waste collectors. Therefore, a clinical history was taken and lung function tests and measurement of the Clara cell protein concentration were carried out. The first results show no elevation of the prevalence of asthma or other lung diseases in waste collectors. Compared with control subjects, waste collectors have a lower forced expiratory volume in the first second and a higher mean Clara cell protein concentration. The prevalence of cardiovascular risk factors such as smoking, obesity and arterial hypertension which are not caused by the occupation is high. Indeed, about 50% of all participants are hypertensive.