LCQ8 : Government is determined to improve HK's air quality

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Following is a question by the Hon Chan Wai-yip, Albert and a written reply by the Secretary for the Environment, Transport and Works, Dr Sarah Liao, at the Legislative Council meeting today (October 23) :

Question:

It has been reported that the records of the Air Pollution Index as measured by the ambient air quality monitoring stations in Tung Chung had been broken twice during the period from the end of August to the beginning of September this year. It was alleged that the pollutants might have originated from the Pearl River Delta region. In this connection, will the government inform this council:

(a) whether it has studied the reasons for the serious air pollution in the area; if so, of the findings; if not, the reasons for that;

(b) of the specific measures to completely solve the air pollution problem in the area; if so, of the details; if not, the reasons for that; and

Reply:

Madam President,

(a) The high Air Pollution Index (API) readings recorded at the Tung Chung air monitoring station in August and September this year were due to high concentrations of ozone formed and accumulated in the Pearl River Delta Region and Hong Kong when we were under the influence of tropical cyclones with hot and sunny weather, and almost stagnant wind.

Ozone is not emitted directly from pollution sources. It is formed as a result of photochemical reaction between nitrogen oxides and volatile organic compounds under sunlight and high temperature. When we are under the influence of a tropical cyclone, the wind can become so stagnant that it is unable to disperse the nitrogen oxides and volatile organic compounds in the air as effectively as under normal weather conditions. As a result, ozone will be formed quickly when sunlight is strongest around noon and its concentrations can rise within a short period of time. However, as sunlight weakens in the late afternoon, the concentrations of ozone can fall also quickly. Therefore, high API caused by high concentrations of ozone will normally last for one to a few hours only. In the few high API incidents at Tung Chung in August and September this year, the longest duration of the API continuing to exceed the 100 level was five hours.

(b) Ozone is a regional air pollution issue. To tackle the ozone problem, we have to reduce the emissions of nitrogen oxides and volatile organic compounds in the Pearl River Delta Region. In this connection, the Hong Kong SAR Government and the Guangdong Provincial Government have reached a consensus to reduce, on a best endeavour basis, by 2010 the emissions of the four major pollutants in the air, including nitrogen oxides and volatile organic compounds, to such levels as will enable Guangdong and Hong Kong to meet their current Air Quality Objectives. Achieving the emission reduction targets will improve the problem of ozone and the regional air quality generally.

The two Governments have agreed to consider in detail the enhanced control measures recommended in the report of a joint study on regional air quality completed earlier this year and, having regard to their feasibility, implement a series of additional measures with the objective of achieving the agreed emission reduction targets by 2010. An expert group has been set up under the Hong Kong-Guangdong Joint Working Group on Sustainable Development and Environmental Protection to take this forward.

(c) The problem of air pollution is one that the whole of Hong Kong is facing. When compared with air monitoring stations in other districts in Hong Kong, the average API readings recorded at the Tung Chung air monitoring station are among the lowest. In any case, the Government is determined to improve Hong Kong's air quality to better protect public health through the joint effort with Guangdong as well as our current programme to reduce emissions from motor vehicles.

To help people to take precautionary measures during days of high API, the Environmental Protection Department reports API readings recorded at its air monitoring stations around the clock and provides precautionary measures for members of the public through its website, telephone hotline and the media. The precautionary measures are set out at Annex.

End/Wednesday, October 23, 2002

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