ASTHMA AND LUNG-CANCER BY DIESEL EXHAUST

Recently, diesel engine powered cars has been increasing steadily in J apan, because diesel engine is powerful and the fuel is less expensive . Diesel exhausts emit some 2 to 20 times more nitrogen dioxide and so me 30 to 100 times more particles than do gasoline engine cars. The ex hausts are main cause of air pollutants in urban area, and people are anxious about that the exhausts may cause lung diseases such as asthma and lung cancers. There are clinical and epidemiological studies on r elationship between asthma and diesel exhausts. However, it is not yet confirmed with experimental study. Here, I will introduce recent expe rimental data that essential features of asthma such as chronic inflam mation with eosinophil-infiltration, mucus hypersecretion and airway h yperresponsiveness has been caused by diesel exhaust particles, and th at the active oxygens generated from diesel exhaust particles may play an important role to cause asthmatic symptoms. The other hand, it is well established that diesel exhausts can cause lung tumors experiment ally using F-344 rats. In this case, it is considered that carcinogens contained in benzene extract-fraction of the diesel exhaust particles are important. However, it has been found that diesel exhaust particl es washed out sufficiently with organic solvent can also cause lung tu mors. Therefore, the significance of carcinogens in diesel exhaust par ticles on the actual carcinogenesis is also introduced.