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Tighter Limits On Pollution Sought

Activists, citing ‘real’ air monitor, seek tighter limits on pollution

Yau Chui-yan – Updated on Sep 07, 2008

Green groups and medical academics in Hong Kong say it is time for the government to adopt World Health Organisation air-quality guidelines, with Greenpeace releasing a downloadable “Real Air Pollution Index” software “widget” based on the international recommendations.

The widget, for computer desktops, can be downloaded free from the environmental group’s website and provides instant updates of air-pollution levels according to the WHO standard.

Edward Chan Yue-fai, campaign manager of Greenpeace China, said it was important for the public not to be misled by the Environmental Protection Department’s Air Pollution Index (API).

“The API corresponds to air- quality objectives which have not been revised since 1987,” he said. “The standard is just too vague.”

University of Science and Technology atmospheric scientist Alexis Lau Kai-hon also called for a change.

“API is a tool to communicate with the public. If it fails to communicate with the public about the health risk, then it is time to consider a new standard,” Dr Lau said.

The API ranges from 0 to 500 and is divided into five bands according to the potential effects on health.

It is calculated by comparing the measured concentrations of major air pollutants with health-related air-quality objectives established under the Air Pollution Control Ordinance.

However, the API is out of kilter with the standards applied by the WHO’s guidelines.

There are times with low API readings when pollutant levels are much higher than the WHO’s recommended maximum intake.

For example, the API in Mong Kok at 5pm on August 4 was 30, but some pollutant levels were much higher than the WHO standard.

According to the Environmental Protection Department, no action needs to be taken when the API is 30, which is considered “medium” pollution.

But the actual level of respirable suspended particulates – particulate matter measuring less than 10 microns – was 14 per cent higher and the level of sulfur dioxide 33 per cent higher than in the WHO guidelines.

Long-term exposure to air with high concentrations of particulate matter is associated with a higher risk of mortality, while high levels of sulfur dioxide have been linked to childhood respiratory disease.

Most recreational runners in Hong Kong responding to questions on a popular running website recently said they would check smog levels before exercising but few said they looked at the API.

However, one runner said he called off runs if the API rose above 100.

Although no country strictly follows all the WHO guidelines, Anthony Hedley, professor of community medicine at the University of Hong Kong, said that was not an excuse for Hong Kong to avoid doing so.

“Hong Kong and the Pearl River Delta are among the most heavily polluted areas in the world,” he said. “Moreover, the WHO standard has embedded studies conducted in the Pearl River region; it is not something generated in another part of the world. There should be no excuse.”

The government replied that a study scheduled to be completed by the end of this year would recommend a new set of air-quality objectives and a corresponding long-term air-quality-management strategy for Hong Kong.

It said it would make reference to the WHO air-quality guidelines.

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