By Keith Bradsher, November 2, 2013
This long exposure picture shows apartment buildings and office blocks
clustered tightly together in Hong Kong's Kowloon district, with the
famous skyline of Hong Kong island in the background.
Hong Kong: Municipal governments all over the world,
particularly in developing countries with rapidly growing fleets of cars
and choking air pollution, have been rushing over the past few years to
force taxis and buses to switch to burning liquefied petroleum gas and
compressed natural gas, frequently offering subsidies for those who do.
an early leader of the trend, Hong Kong, said Friday that the city's
shift over the past decade to almost complete dependence on liquefied
petroleum gas, or LPG, for light commercial vehicles had produced
unintended consequences. Concentrations of nitrogen dioxide, one of the
most important contributors to smog, surged by a fifth in Hong Kong's
air from 2008 to 2012, and a team of local and international scientists
have traced the cause to LPG-fueled vehicles, Hong Kong environmental
regulators said at a news conference.
The problem lies in the
taxis' and minibuses' catalytic converters, said Christine Loh, the
undersecretary for the environment. Unless replaced every 18 months for
cars and light buses that are driven nearly around the clock, the
catalytic converters become fouled, and the vehicles begin emitting
extremely high levels of pollution.
"The LPG vehicles, which are
supposed to be cleaner, are spewing out very high levels of nitrogen,"
she said. Although relatively few natural-gas-powered vehicles have been
deployed on a large scale in Hong Kong, they would pose the same
problems, she added.
As a result, the Hong Kong government will
pay for the replacement of catalytic converters on the city's entire
privately owned fleet of roughly 18,000 taxis and several thousand
minibuses, Loh said. Pang Sik-wing, the city's principal environmental
protection officer for air sciences, said the replacement effort would
cost about $1,290 per vehicle.
After the first free replacement,
taxi and minibus owners will be responsible for replacing catalytic
converters every year and a half at their own expense. Hong Kong will
deploy five mobile sensor systems next year to measure the pollution
from passing vehicles and send automatic notices to the registered
owners of any vehicle exceeding emissions standards, requiring them to
take in their vehicles for repairs or risk losing their vehicle
"We will strictly enforce the emissions standard," Pang said at the news conference.
areas of northeastern China struggled a week ago with smog so thick
that schools closed and motorists had to slow down to drive through the
murky air. While that smog has been linked overwhelmingly to coal
consumption, vehicles have also played a role, particularly
diesel-burning heavy trucks.
Air pollution tends to be less
severe in Hong Kong than in northern Chinese cities, but it is still
much worse than in the United States or the EU. Much of the pollution in
Hong Kong is generated by factories just across the border in mainland
China. Referring to air quality standards set by the World Health
Organization in Geneva, Loh said, "Hong Kong could shut off tomorrow: We
would still not meet WHO standards because there are emissions from our