近年来,由于世界汽车工业的飞速发展及汽车保有量的剧增,随之而来的汽车排放问题更加突出。特别是在城市,汽车排放物已严重的污染了环境,危害了人们的健康。为此,世界各国都相应制定了越来越严格的排放标准,我国已颁布了控制汽、柴油车和车用汽、柴油机污染物排放的7个标准。然而,就我国目前城市的汽车排放污染而言,有日趋严重的趋势。据环 In recent years, due to the rapid development of the world automobile industry and the rapid increase in car ownership, the issue of automobile emissions has become more prominent. Especially in cities, car emissions have seriously polluted the environment and endanger people’s health. To this end, all countries in the world have formulated more and more stringent emission standards. China has promulgated seven standards to control emissions of gasoline, diesel vehicles and automobile steam and diesel engines. However, as far as China’s current urban vehicle emissions pollution, there is a growing trend. According to the ring