Polluting marine vessels must find no welcome in Hong Kong

In a recent South China Morning Post online poll, readers named pollution as Hong Kong's biggest eyesore. The days when the city's skyline is shrouded in smog come to mind. Equally, we think of the sight of giant ocean-going vessels sailing in local waters and belching out smoke.

In March, the government published the 2012 emission inventory for Hong Kong. Marine transport continues to be the main source of these pollutants: nitrogen oxides, sulphur dioxide and the PM10 and PM2.5 particulate matter. In particular, marine vessels emitted about 16,500 tonnes of sulphur dioxide, contributing half of the total share.

The amount of pollution last year - which saw the opening of the Kai Tak cruise terminal - is likely to have been worse.

Last October, when the second cruise ship arrived at Kai Tak, we measured the air quality along the shore in Kwun Tong and found that the readings of PM2.5 jumped from 30 micrograms per cubic metre to 60 micrograms per cubic metre (more than twice the World Health Organisation guideline for 24 hours).

More and more ports in the world have adopted more stringent control measures to reduce the impact of ship emissions on local air quality, such as by tightening limits on the sulphur content of marine fuels, or requiring big ocean-going vessels running on bunker fuel to switch to cleaner fuel when at berth.

The International Maritime Organisation also provides mechanisms to allow countries to set up emission control areas, so that vessels passing through have to comply with the more stringent controls. In addition, onshore power facilities have been set up to eliminate polluting emissions in the port area.

At present, the government encourages ocean-going vessels to use fuel with 0.5 per cent sulphur content or less while at berth, through the reduction of fees for the use of port facilities and light. However, due to its voluntary nature, it is difficult to ensure ocean-going vessels join the scheme.