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Air Pollution For Dummies

Tuesday, October 10, 2006 - ALAN SEIGRIST

It is often said by government officials and the media that about 80 per cent of the air pollution in Hong Kong comes from the Pearl River Delta. As a result of this general truth, the government has focused a great deal of effort on solving the cross-border pollution problem. In particular, it has tried to get the number of coal-fired power plants in the delta reduced, and replaced with natural-gas-powered plants.

While I wholeheartedly encourage the government to continue such efforts, they will not provide meaningful improvement for at least a decade. We first need to understand that this oft-quoted "80 per cent of our air pollution comes from the delta" is a misconception: that is not the pollution we breathe.

In fact, about 50 per cent of the air pollution you breathe while walking, shopping or living next to a typical Hong Kong city street comes from the traffic right in front of you - mostly from diesel trucks and buses.

This statistic is clearly illustrated by the Environmental Protection Department's air pollution index (API) for last year. Air pollution was rated "high" or worse over 42 per cent of the year (measured hourly) at general testing stations - and 77 per cent of the year at roadside testing stations.

As a general rule of thumb, a "high" API reading rates as a health hazard under the European Union or World Health Organisation standards.

The air you breathe on the street cannot be blamed on the Pearl River Delta: this is home-grown pollution. If you average out the difference between these two percentages - and assume that a small portion of the general-station API reading comes from local road traffic - that means approximately 50 per cent of the air pollution you breathe comes directly from our road traffic.

Therefore, blaming 80 per cent of Hong Kong's air pollution problem on Guangdong is a gross misunderstanding of the real health threat.

Sarah Liao Sau-tung, secretary for the environment, transport and works, regularly highlights the government's adoption of Euro IV standards for all new vehicles. But the most polluting vehicles on the road today are the vast majority of diesel-burning buses, minibuses, commercial vehicles and ferry fleets - built to pre-Euro IV standards. They represent 30 per cent of the total vehicle fleet on the roads in Hong Kong, and contribute about 80 per cent of the roadside air pollution.

Fixing this would actually be quite straightforward. There are various solutions that could be instituted and completed within the next 18 months, which could make a drastic improvement.

The first is adding bio-diesel fuel to the petroleum diesel sold here. Not only does bio-diesel burn significantly more cleanly, it's also the ideal way to recycle used frying oil in Hong Kong. This would support our energy needs from a locally available fuel source.

The second is an outright ban on the dirty, industrial-grade diesel used in local ferry and construction fleets, as well as in local factories.

Third, do a wholesale conversion of the local bus and ferry franchise fleets from old, standard diesel motors and engines to the Euro IV standard.

Fourth, require all local commercial trucking to have a full tank of Hong Kong diesel fuel (which is substantially cleaner than mainland diesel) before they are allowed to cross the border into Guangdong.

Fifth, change the voluntary conversion scheme of minibuses to LPG (which ended last year) into a mandatory programme. About 2,500 of the 4,600 minibuses have been converted: finish the job.

Finally, we need to adopt a strategy on traffic congestion. The easiest step would be a rush-hour congestion charge for the Cross-Harbour Tunnel, which would divert traffic from downtown Hong Kong to the eastern and western harbour tunnels.

Alan Seigrist is chairman of the environmental committee of the American Chamber of Commerce.