一、前言随着现代工业的发展,大气污染在许多国家中,已经成为一个严重的、急待解决的问题。它给人们生活带来了很大危害。工业发达的国家,汽车排气污染占大气污染很大的比例。因此,对汽车排放的污染物均加以严格的限制,并制定出有关的法令和限制标准。各国都在进行大量的降低汽车排气污染的研究工作,使汽车排放的污染物达到本国政府所规定的限制标准。 I. Introduction With the development of modern industry, air pollution has become a serious and urgent issue in many countries. It has brought great harm to people’s lives. Industrialized countries, automobile exhaust pollution accounted for a large proportion of air pollution. Therefore, the vehicle emissions of pollutants are strictly limited, and to develop the relevant laws and restrictions and standards. Various countries are carrying out a large number of research efforts to reduce automobile exhaust pollution, so that the pollutants emitted by automobiles reach the limit standards set by their own governments.