*************************************************
Following is a question by the Hon Chan Hak-kan and a reply by the Acting Secretary for the Environment, Dr Kitty Poon, in the Legislative Council today (January 6):
Question:
At present, the Environmental Protection Department makes use of the data collected by three roadside and 11 general air quality monitoring stations (AQMSs) to compile the Air Pollution Index and publish the relevant summary for reference of the public. There have been comments that AQMSs fail to comprehensively reflect the air pollution situation in Hong Kong as their number is inadequate. In this connection, will the Government inform this Council:
(a) whether the Government will, before deciding whether or not to install additional AQMSs, consult green groups and people in the districts; if it will, of the details of consultation; if not, the reasons for that, and whether it will consider setting up such a consultation mechanism;
(b) given that roadside AQMSs are set up only in Central, Causeway Bay and Mong Kok at present, whether the Government will reconsider installing roadside AQMSs in other busy districts and if so, of the details of consideration, including the districts and locations at which the additional roadside AQMSs are to be installed, as well as the installation timetable and the methods of collecting data; if not, the reasons for that; and
(c) whether it will consider the provision of at least one general AQMS in each of the 18 districts in Hong Kong, so as to facilitate members of the public to have a better grasp of the air pollution situation in the various districts; if so, of the details; if not, the reasons for that?
Reply:
President,
The current air quality monitoring network (monitoring network) in Hong Kong comprises 14 fixed air quality monitoring stations (AQMSs) - 11 general and 3 roadside AQMSs. The main objective of setting up the monitoring network is to collect data for assessing the impact of air pollution on the public, formulating air quality management strategy as well as evaluating its effectiveness. The Environmental Protection Department (EPD) also publishes Air Pollution Indices (API) hourly based on the real-time data collected by the monitoring network for the public's reference.
As a small and densely populated city, Hong Kong's economic activities are mainly commercial and financial. Air pollutants in urban areas and new towns mainly come from vehicle emissions. Given the same source of pollution, the levels of air pollution in different districts are mainly determined by their respective types and density of development. The levels of air pollution in districts with similar types and density of development are more or less the same. The current monitoring network covers the major areas from East to West and from South to North of the territory. In terms of land uses, it also covers different types and density of development, such as residential areas, mixed residential/commercial areas, mixed residential/commercial/industrial areas, rural areas and busy urban roadside areas. Therefore, the current monitoring network can effectively reflect the overall air pollution situation in Hong Kong, serve as a reliable basis for drawing up an air quality management strategy and measures, and provide the public with representative data on air quality.
My reply to the questions raised by the Hon Chan is as follows:
(a) To collect representative air quality data, we need to consider a number of factors in designing the distribution of AQMSs. They include the spatial distribution of the monitoring network, coverage of different types of development areas (e.g. urban areas, new towns and rural areas), distribution of local population, traffic flow and pollution sources, representativeness in terms of the local air quality, topography and meteorology.
In deciding on the locations, design and operation of individual AQMSs, the EPD makes reference to the United States Environmental Protection Agency's guidelines to ensure the collection of representative data by the monitoring stations. Our monitoring network's design and operation meet the international standards and is certified by the Hong Kong Laboratory Accreditation Scheme.
We have set up AQMSs to monitor the local air quality since the early 1980s. In setting up the AQMSs in the early days, we mainly considered the above technical factors. The District Councils (DCs) were not consulted on these relevant issues. However, given the public's rising awareness of environmental protection over the past decade or so, in planning roadside AQMSs in recent years, the EPD has consulted the relevant DCs and listened to the views of the local community on the locations, design and operation of the AQMSs to avoid hindering nearby traffic and pedestrian flow or creating negative visual impact. For instance, when the EPD planned in 1996 to set up a roadside AQMS in the Central and Western (C&W) District to assess the impact of vehicle emissions on pedestrians, we took into account a number of factors in selecting the site, including the need to set up the roadside AQMS at a location with heavy vehicular and pedestrian traffic and to reflect the phenomenon of "canyon-type" streets in built-up areas in Hong Kong. In addition, the airflow near the AQMS must be free from interference by objects such as trees, plants and flyovers in the vicinity. The requirements of sampling standards, ease of operation, staff safety, possible impact of the AQMS on nearby pedestrian flow and vista, and foreseeable redevelopment plans for nearby buildings were also amongst the host of relevant factors that had to be considered. At the initial stage of site selection, the EPD carried out site inspections at 60 locations in the district. After an in-depth study, three suitable locations were identified for consultation with the Environmental and Works Committee of the C&W DC before the present site at the junction of Des Voeux Road Central and Chater Road in Central was selected for setting up the AQMS, which came into operation in 1998.
(b) All of the three existing roadside AQMSs in Hong Kong are located in built-up urban areas with heavy vehicular and pedestrian traffic. They monitor roadside air quality, in particular the impact of vehicle emissions on pedestrians, and provide real-time roadside API. The three roadside AQMSs in Causeway Bay, Central and Mong Kok cover the most common types of land uses with a relatively high density in urban areas, including commercial, commercial-cum-residential and financial. Therefore, the data from these roadside AQMSs are representative of the roadside air quality of typical places with heavy vehicular and pedestrian traffic in the urban areas. As such, we consider it unnecessary to increase the number of roadside AQMSs.
(c) Formed by 11 general AQMSs, the current monitoring network covers the major areas from East to West and from South to North of the territory. In terms of land uses, it also covers different types of development, such as urban areas, new towns and rural areas. The data from the monitoring network are representative of the air quality of various districts. For instance, Tsuen Wan, Kwai Chung, Sham Shui Po and Kwun Tong have similar overall development density. The four AQMSs in these districts gave a mean API ranging from 43 to 45 in 2009. This indicates that the overall air quality in these districts is similar and the measurements from these AQMSs can reflect the air quality in the urban area stretching from Kowloon peninsula to Tsuen Wan. As for the remaining seven AQMSs, the data from the AQMSs in the C&W District and Eastern District can reflect the situation in the urban areas on Hong Kong Island; the data from the AQMSs in Tai Po, Shatin, Yuen Long and Tung Chung can reflect the air quality in new towns in the New Territories and Lantau Island; and the data from the AQMS in Tap Mun can reflect the air quality in rural areas. In short, the data from the current monitoring network can serve as a reliable basis for drawing up an air quality management strategy and measures while providing the public with representative data on air quality. We do not consider it necessary to set up an AQMS in each of the 18 districts.
Ends/Wednesday, January 6, 2010
Issued at HKT 15:40
NNNN
