Hong Kong's plans to impose an emissions control zone for ocean-going vessels may be a major policy shift for China and reduce pollution in the Pearl River Delta area.
But first the central government must file an application with the international regulatory body for maritime affairs, undersecretary for the environment Christine Loh Kung-wai said
The city may receive approval by summer for a law making all ocean-going vessels berthing in Hong Kong switch to a lower-sulphur fuel from early next year.
This would set a precedent for other cities in the region, Loh told the South China Morning Post.
"When you believe in something, it's important that you show other people you are serious about it and do it first," she said.
Ocean-going vessels were the largest source of emissions of respirable suspended particulates and sulphur dioxide in 2011, according to the Environmental Protection Department.
Many experts believe any significant cut in shipping pollution would require a collective effort by cities in the delta area.
Hong Kong has been in talks with Shenzhen to create a low-emissions zone around the delta.
"We feel we needed to explain why we thought this was important and what the steps up to it are … This will be a very major policy shift for China as a whole … Our Chinese counterparts are treating this very seriously."
A region-wide emissions control zone must be approved by the UN International Maritime Organisation. Such zones are already in force in the Baltic Sea, North Sea and Caribbean Sea, while North America has a continent-wide zone. The establishment of a regional zone would be a first for Asia, Loh noted.
She said the switch to lower-sulphur fuel, coupled with another piece of tabled legislation for local vessels to use cleaner marine diesel, could reduce local sulphur dioxide emissions by an estimated 20 per cent. Recently, the department has formalised a link with the US Environmental Protection Agency to exchange research on air quality and control measures.
Regional co-operation is also under way. Loh said the Environment Bureau had been working closely with the Guangdong government as well as with Macau on sharing air quality research and expanding the 16-station Regional Air Quality Monitoring Network. Thirteen stations are in Guangdong, with the other three in Hong Kong.
"What we have in Hong Kong and Guangdong - Macau is now joining - is the most sophisticated and reliable set of data in the whole of China," Loh said.
"Having this network and this reliable data is critical in helping us understand the mix of pollutants and what the control measures should be."
Hong Kong and Guangdong have put in place a second set of air quality targets - running between 2012 and 2020 - that are lower than those defined in the first phase, from 2002 to 2010.
But Loh said regional cuts in emissions had been "remarkable". The lower margins did not represent a setback, she said, and compared pollution reduction to losing weight.
"For every pound that you lose, it gets more difficult," she said.