HONG KONG Since the introduction of the European Emission Standards in 1992, KMB (Kowloon Motor Bus) has successfully reduced the average particulate emission levels of its bus fleet by 92%, while the emission of nitrogen oxides has been reduced by 57.2% (as of the end of December 2011).
Mr. Kane Shum, KMB’s principal engineer, said: “KMB has a total of around 3,800 buses. It is neither environmentally friendly nor economically feasible to replace the entire bus fleet with the latest Euro models at one time.
“Nonetheless, we fully understand the importance of good air quality. Therefore, we have spared no effort in continuously improving the environmental performance of our bus fleet while delivering quality bus services.”
KMB has consistently introduced the latest Euro engines available. From the introduction of Euro I engines in 1992, followed by Euro II in 1996, Euro III in 2001, Euro IV in 2006 to the latest Euro V engines in 2009. At the end of 2011, KMB had 309 Euro V buses and 108 Euro IV buses in its fleet.
As of 2001, catalytic converters were installed on buses with Euro I engines and pre-Euro engines. Coupled with the use of ultra-low sulphur diesel (0.005% sulphur content), their exhaust emissions were brought up to the standards of Euro II and Euro I engines respectively in terms of particulate matter. This environmental strategy was built upon in 2007, with the retrofitting of Diesel Particulate Filters (DPFs) on its Euro II and Euro III buses, upgrading their exhaust emissions to Euro IV / V standards in terms of particulate matter.
As of 2008 KMB has adopted “Euro V Diesel”, which has only 0.001% sulphur content. Besides directly improving the emissions of buses, this Near Zero Sulphur Diesel (NZSD) also enhances the effectiveness of catalytic converters and diesel particulate filters, thus indirectly improving the emission levels of buses of different ages. NZSD has now been adopted fleetwise.
Mr. Shum added: “Looking to the future, we will continue to adopt new technologies and further enhance the environmental performance of our bus fleet on the one hand, while actively embarking on the study and trial of zeroemission technologies on the other to help bring about a cleaner and quieter Hong Kong.”