Exhaust gases
Breathless in HK

By Kevin Au
     According to the Transport Department, there are 266 licensed vehicles for every kilometre of road in Hong Kong. A very high degree of air pollution is caused by emissions from these cars.

     Helena Chui
     Even places far from the urban centre, such as the campus of The Chinese University of Hong Kong, cannot escape the air pollution.
     Campus buses at the Chinese University are frequently criticized for their emissions of dense black smoke, especially when climbing uphill from the railway station to midlevels.
     Mr. Timothy Chan, head of the Transport Unit at the Chinese University, said that campus buses are checked each year.
     “They will not be issued a license if the car testing officer at the Transport Department disqualifies them in the annual tests,” said Mr. Chan.
     Elsewhere in Hong Kong, ill-equipped garages and their unqualified technicians are often blamed for the large amount of pollutants emitted by vehicles.
     Mr. Iain Seymour-Hart, head of the Motor Vehicle Engineering Department at Lee Wai Lee Technical Institute, admitted this situation exists especially in so-called “backstreet” garages.
     “Young technicians acquire good theoretical foundation in the 4-year training,” he said. “But it is very difficult to retain experienced technicians in the field because most of garages’ technicians change their jobs frequently.”
     However, the chairperson of the Institute of Advanced Motorists Hong Kong, Mr. Dragon Young, argued that standard of garage technicians is not as bad as perceived.
     “Those technicians have usually worked in car factories for a certain period of time or been trained in foreign countries,” said Mr. Young.
     “If they are not good enough, the market will eliminate them naturally.”
     He further said that it’s a common practice for garages to double check the vehicles before they hand them back to the car owners to ensure the cars are all right to go back onto the roads.
     Mr. Seymour-Hart said most car owners do not follow preventive maintenance guides and do not check their cars regularly.
     “After being driven for more than 5,000 kilometres, vehicles need to be checked and given appropriate engine service,” he said.
     To reduce the amount of exhaust, the Government is looking at the types of fuel employed. The use of diesel, widely used by heavy vehicles such as trucks and buses, is responsible for the greatest proportion of particulates discharged. Hence, liquefied petroleum gas is being introduced into Hong Kong on a limited basis as an alternative to diesel fuel.
     Such a move is not unprecedented: The introduction of unleaded petrol in 1991 was a major step in reducing the amount of lead in the atmosphere.
     According to the Environmental Protection Department, unleaded petrol now accounts for about 80 percent of all petrol sales.
     Liquified petroleum gas changes from a liquid into gas when released under normal atmospheric pressure. This enables fuel to be burnt completely without producing black smoke.
     More than 4 million vehicles powered by liquified petroleum gas are in use in about 30 countries. Some 97 percent of taxis in Japan are powered by liquified petroleum gas.
     In Hong Kong fears have been expressed concerning potential explosions from improper handling and storage of liquified petroleum gas. However, the fears may not be fully justified.
     “LPG is stored in two containers in petrol stations to minimize chances of leakage,” said Mr. Seymour-Hart.
     In any case, switching all diesel taxis in Hong Kong to liquified petroleum gas would reduce particulate emissions 30 percent, authorities estimate.



 Aircraft toilets




January 1998

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