Green group will offer alternative smog index

PUBLISHED : Wednesday, 06 June, 2007, 12:00am
UPDATED : Wednesday, 06 June, 2007, 12:00am

A green group will launch a current air-pollution index that it says will provide the public with up-to-date information now lacking in the existing reporting system.

The index will be launched on July 1 in what Friends of the Earth says will be a gift to celebrate the 10th anniversary of the handover and to protect public health from air pollution risks.

The group said it was designed in response to a recent suggestion by the Council for Sustainable Development to set up an alert system for air pollution.

The difference between the current index and the air pollution index (API) released by the Environmental Protection Department is that the current index can offer pollution data that reflects the latest situation.

The API reports levels of sulfur dioxide, nitrogen dioxide, ozone and carbon monoxide on an hourly-average basis. But respirable suspended particles are only reported on a 24-hour average, resulting in a time lag.

'That is to say, if the air quality worsens to a very high level, the public will not be notified concurrently which could threaten the lives of people with heart disease.

'By the same token, if air quality improves, the API cannot make an instant reflection, so some activities could be cancelled unnecessarily,' a spokesman for the group said.

To better reflect pollution levels in a timely manner, the group - with help from Alexis Lau Kai-hon, an atmospheric scientist from the University of Science and Technology - will issue an index based on an hourly average.

A mock exercise to illustrate the difference between the two indexes found that the pollution index at 8am on February 12, 2006 when the Standard Chartered Marathon was held, was actually only 84 instead of 132 as reported by the environmental department.

In response to doubts cast by the group, a department spokesman said staff found few problems with its API system, which was similar to ones operating in Singapore and Taipei.

'The method deployed by Friends of the Earth to calculate API appears to be arbitrary and selective,' he said.

He said the department would revisit the reporting system for the API in a scientific way under a contract awarded to Ove Arup & Partners yesterday to review air quality objectives.