[Behaviour of the lung as an organ of absorption and reaction when air-borne contaminants are inhaled (author's transl)].

The pulmonary resorption of air pollutants constitute a significant factor for the whole body burden of men, as can be shown for lead, SO2 and CO. Particle size as well as water and lipid solubility of the noxious agents are important variables for the extent of the interaction with the pulmonary surface. Main objects for the inhalative pollutants are the bronchioli terminales and the respiratory epithel. The electronmicroscopic investigations point out a specific irritability of these structures as far as lead, oxydants and fibers are concerned. Comparatively low concentrations of the agents produce, in chronic exposure, changes in the caliber of the small airways and widening of the ductus alveolares and the alveoli. In addition to the reduction of the inner lungsurface one observes a thickening of the diffusion barrier in loco through some harmful substances. A number of pollutants influence a primary cytotoxic effect on alveolar macrophages. Thereby the bacterial infection resistance of the lung is reduced; moreover the phagozytes play an important part for the detoxification of carcinogenic carbohydrates. Hence the lung functions as a resorptionorgan, as a protectionorgan and as an object of damage for various air pollutants.