Gasp, it's worse than we thought

PUBLISHED : Wednesday, 18 January, 2012, 12:00am
UPDATED : Wednesday, 18 January, 2012, 12:00am

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Air pollution in Hong Kong is more harmful than previously thought, according to a revamped environmental index run by researchers at the University of Hong Kong.

While previous estimates by the researchers put the number of premature deaths per year over the past five years at 1,000, the current figures estimate that 3,200 people die prematurely from pollution-related illnesses. They put the total economic cost per year of pollution at HK$40 billion, up from HK$16 billion.

'Even though these new figures are higher, they're still conservative figures that account for only the short-term health impacts of air pollution,' said Professor Anthony Hedley, the public health specialist behind the index.

The Hedley Environmental Index attempts to illustrate the 'silent cost' of pollution - with health effects that don't immediately translate to a specific disease.

The revamped index was introduced yesterday - the same day as the government released its air quality objectives, which show no revision from targets suggested in a 2009 consultation and are still well above limits set by the World Health Organisation, according to Hedley and his team.

They said the current air pollution interpretation was still inadequate and misled the public about the true risks of air pollution.

Professor Lam Tai-hing, director of HKU's School of Public Health, said: 'The government is looking at an acceptable high of 125 [micrograms per cubic metre] for sulphur dioxide. The WHO considers anything above 20 to be bad for human health.'

The WHO set guidelines in 2005 with limits for pollutant levels. Any concentration higher than the limit is said to harm our health. Ailments scientists link to air pollution include lung cancer, chronic bronchitis and pneumonia. Studies in the past year suggest it may clog major arteries, affect childhood leukaemia and damage lung growth and development in children.

The difference in figures for the revised index come from adjustments made to reflect the reality of living in Hong Kong. For example, the weighting of roadside pollution was increased from 50 per cent to 60 per cent because most Hongkongers spend a lot of time near roads. Nitrogen dioxide, a common byproduct in roadside pollution, was also given a higher rating to reflect this fact, Hedley said.

The index takes air pollution readings from the government and correlates this to figures on premature deaths, doctor visits, and days spent in hospital with illnesses associated with toxins in the air to come up with rough figures to illustrate the hidden costs of pollution. They measure four common pollutants - nitrogen dioxide, sulphur dioxide, ozone and other small particles in the air.

The new version provides a more user friendly health-risk warning meter, based on WHO guidelines, that can be distributed through Facebook - a real-time pollution map at 14 different monitoring stations across Hong Kong; a running tally of avoidable harm to the community in terms of doctor visits, hospital stays and deaths; monthly and yearly summaries of clear and polluted days; and tangible and intangible costs to the community.

'The EPD [Environmental Protection Department] has a good monitoring network, but it's misinterpreting these numbers. We take their data and translate the risk,' said Hedley, adding that contrary to popular belief a large part of pollution in Hong Kong is locally generated.

Hedley and Mike Kilburn, head of environmental strategy for local think tank the Civic Exchange, say the government is not doing enough to tackle these issues. 'It's things like not forcing companies to retire the old buses, which pollute the most,' said Kilburn.

He was disappointed with the government standards announced yesterday and asked why it took two years to announce no change in policy.