NOx Reduction Effects of the Policy to Reduce Diesel Automobiles and its Influence on Price Change

Abstract

Although motorisation has contributed significantly towards Japan’s present stable economic growth, the increase in automobiles has also cause social problems such as traffic jam, traffic noise, air pollution due to automobile exhaust gas and so on. NOx emission has especially become a more serious problem in the urban areas. This is because it brings about some diseases such as lung cancer and asthma. The nitrogen oxidant pollutant (NOx) volume is increasing and has exceeded the environmental quality standard in the urban areas. Although most of the air pollutant problems have improved in line with the appropriate regulation policies, the NOx problem has still remained. The main cause of this NOx pollutant problem is due to the use of the diesel automobiles. As the statistical data shows, NOx emission from automobiles accounts for 70% of the overall emission caused by human activities, where, out of this 70%, about 50% is attributed to diesel automobiles [EA 1992]. This is despite the fact that diesel automobiles only accounts for 20% of the overall total number of automobiles. The technical improvement of the diesel engine to reduce the environmental problems has some trade-off relations between the NOx reduction and the suspended particulate matter. Moreover, the number of diesel automobiles has steadily increased and it has become more widely used beacause of its economical advantages.