Particulate Substances as Air Pollution Factors

from Biological Standpoint

Abstract

Health effects of particulate substances in the environmental air, especially those of diesel exhaust particles and asbestos fibers, were reviewed. In contrast to toxic gas which demonstrates acute and transitory effect on human airway, particulates deposit in the lung show chronic and long-standing hazard to human health, resulting in different diseases.
Diesel exhaust particles reveal mutagenicity in vitro experiments, and nitropyren is now considered to be diesel-characteristic, mutagenic hydrocarbon. Epithelial DNA damage, hyperplastic foci of the airway epithelia and adenomas or carcinomas of the lung were produced around the particle deposition in animal experiments. It is reported that suspended particulate matter in the air along automobile roads consists of diesel exhuast, in over 30%, and the roles of which on human lung cancer formation are to be clarified in future.
Short asbestos fibers are suspended in the environmental air of industrialized society, are inhaled and deposited in the lungs of urban residents, and are calculated to be over 10/ in number for the whole lung. Occupational exposure to asbestos increases incidences of malignant pleural mesothelioma and lung cancer, especially among smokers in the latter, and the results of animal experiments coincide with those of humans. In vitro studies revealed prominent absorption of chemicals by the fiber, and suggested accelerated uptake of carinogenic substances into nuclei due to cell membrane disturbance by the fibers, however, co-carcinogenicity of asbestos may be the more important factor for pathogeneis of lung cancer in humans.