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Cleaner air objectives are inadequate


We welcome the long-overdue review of air quality objectives and the newly proposed strategies for air pollution control by the Environmental Protection Department.

The underlying principles of protecting public health, the long-term goal of adopting the targets set by the World Health Organisation and the need for a regular review of Hong Kong’s air quality objectives, are all clearly stated in the review document. However, the recommended objectives are unnecessarily conservative.

Rather than aiming for the WHO’s stringent air quality guidelines, the department has chosen to adopt the interim targets, which are inadequate for health protection.

For example, the newly recommended objectives for annual PM10 (particulates) concentrations, set at the WHO Interim Target 2 of 50 micrograms per cubic metre, is a decrease of only 5mcg per square metre from the outdated objective of 55mcg. Both values far exceed the WHO guideline of 20mcg. All other air quality objectives are, where applicable, set at the even more lenient WHO Interim Targets 1. The absence of a timetable for the achievement of these new targets, and for the adoption of the next targets, gives the public no indication as to when Hong Kong is expected to reach the ultimate air quality guidelines.

The Environmental Protection Department recommends 19 strategies and lays out cost-benefit analyses of the options. The findings of a cost-benefit approach depend on the comprehensiveness of the list of benefits and how they are valued and are too technical for a public consultation. It would be easier for the public to understand if the actual health consequences, for example the number of lives that could be saved, or episodes of illness that could be avoided, are presented for each strategy.

The department’s strategies are limited by thinking inside the box. The control of old diesel vehicles is a useful and important strategy, but alternative modes of transport, such as trolley buses, light rail and modernised trams, are not even mentioned.

While marine air pollution from ocean-going vessels is also recognised as a problem, its solution – which requires a joint effort between all of the ports in the Pearl River Delta and major seaports further north – has not been addressed. Air pollution continues to pose a major public health problem in Hong Kong. The government must take bolder control measures to improve our air quality.

Wong Tze-wai, professor, Sian Griffiths, director, Andromeda Wong, research assistant, school of public health, faculty of medicine, Chinese University of Hong Kong

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