Greens call for study on ozone in Tung Chung

North Lantau new town's expansion should be put on hold until its unique pollution problems are better understood, Green Power argues

PUBLISHED : Friday, 13 June, 2014, 4:48am
UPDATED : Friday, 13 June, 2014, 4:48am

The government must carry out more studies on local air pollution if it is to convince the public that further expansion of Tung Chung new town will not pose a risk to health, a green group says.

Green Power made the call after reviewing more than a decade of air quality data for the north Lantau new town and concluding that Tung Chung suffered levels of ozone not seen in other urban areas. The group believes more research is needed into why the area experiences such a unique level of ozone.

It suspects officials have deliberately played down air pollution in two rounds of consultation on plans to double the town's population to 220,000 people by using reclaimed land and land near a river valley.

But the government said there was no need for studies as ozone would mix with other substances to create other pollutants, such as nitrogen dioxide, that were monitored. Areas with heavy traffic tended to have lower ozone for that reason, it added.

Dr Cheng Luk-ki, Green Power's top scientist, said the group compared 12 areas of the city according to how often they were found to have "very high" levels of ambient air pollution in the government's pollution index. Tung Chung, developed in the 1990s alongside the airport, was in the top three for pollution. Ozone was the dominant pollutant. In the 14 years ending last year, there were 174 days on which levels of ozone exceeded government standards; Yuen Long, the second-worst area, was over the standard on just 64 days.

Ozone is produced through chemical reactions between nitrogen oxides from emissions and volatile organic compounds under sunlight. Long-term exposure is linked to asthma, bronchitis, heart attacks and even death.

Group chief executive Man Chi-sum said new towns were intended to "improve people's … living environment" and there was "little ground" to expand in a polluted area.

An Environmental Protection Department spokesman said ozone would fall if the area became busier, though "this is not an air quality improvement". He said new emissions controls were being introduced on Lantau.