Air pollution index based on invalid data
Winston Chu Ka-sun puts appropriate emphasis on the root causes of our bad air and its harm to the health of the population in 'Death wish granted' (May 2).
His pithy comments contrast sharply with the bland optimism and misleading assurances of officialdom. A major recurring problem is the government's continuing use of the outdated 1987 Hong Kong Air Quality Objectives. The recent publication of the Environmental Protection Department's report on the Pearl River Delta Regional Air Quality Monitoring Network can be cautiously welcomed as a potentially reliable source of information about population exposure. But we are dismayed to see that it uses the mainland's National Ambient Air Quality Standards as the basis for a regional air quality index. Those are even more lax than Hong Kong's air quality objectives.
The government seems to be determined to avoid, or delay indefinitely, the adoption of new evidence-based air quality objectives despite the global consensus embodied in the new World Health Organisation Air Quality Guidelines.
The mandatory air pollution warnings proposed by the Sustainable Development Council, 'Bad-air alarm proposed to protect health' (April 29), are unlikely to make a worthwhile difference to public health.
As an instrument of risk communication, any index based on invalid air quality objectives will contribute little to either 'education' or health protection.
It will wrongly define what is a significant threat to health, and even if the suggested mitigation measures did significantly reduce exposure, which we doubt, warnings would come too late and not address the major sources of the cause of pollution.
