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Following is a question by the Dr Hon Kwok Ka-ki and a written reply by the Secretary for the Environment, Mr Wong Kam-sing, in the Legislative Council today (June 25):
Question:
The Environmental Protection Department (EPD) launched the Air Quality Health Index (AQHI) on December 30, 2013 to provide the public with information on the health risk of air pollution. The EPD updates the AQHI hourly on the basis of the data (including concentrations of pollutants such as ozone, nitrogen dioxide, sulphur dioxide, respirable suspended particulates and fine suspended particulates) recorded by the general monitoring stations and roadside monitoring stations in various districts. During the period between 1pm to 7pm on June 8, 2014, the AQHI in Tung Chung persistently stood at 10+, the highest level of the index, with health risk of the "serious" category. During the same period, the AQHIs in most other districts also reached level 10+ in certain intervals. In this connection, will the Government inform this Council:
(1) of the respective cumulative duration of various health risk categories as indicated by the monitoring stations in various districts since December 30, 2013, to be set out in Annex I;
(2) apart from setting on its web site the recommended precautionary actions for members of the public (including people with heart or respiratory illnesses and outdoor workers) to be taken under different AQHIs, whether the EPD has taken special measures in districts where, and on any day when, AQHIs of level 7 or above were recorded, in order to protect the health of the public; if the EPD has, of the details;
(3) whether various government departments have jointly devised measures to improve the air quality in Hong Kong, particularly Tung Chung and the urban areas, based on the AQHIs recorded by monitoring stations in various districts; if they have, of the details; if not, whether they will assess the effectiveness of introducing the AQHI system;
(4) whether it studied in the past three years the major sources of air pollutants in Hong Kong; if it did, of the details;
(5) whether it studied in the past three years the correlation between direction and speed of wind and the AQHI of level 7 or above recorded in different districts; if it did, of the findings;
(6) whether it has studied the reasons for the relatively high AQHIs recorded in some districts, e.g. Tung Chung; whether the authorities, prior to planning the construction of large-scale infrastructural facilities in those districts, have assessed the impacts of such facilities on the air quality of those districts and the neighbouring areas, both during the construction period and after commissioning of such facilities; if they have, of the details; and
(7) whether it will install additional general or roadside monitoring stations at suitable locations to facilitate more comprehensive monitoring of air quality of various districts; if it will, of the details?
Reply:
President,
(1) The respective cumulative durations of various health risk categories under the Air Quality Health Index (AQHI) recorded by the 15 air quality monitoring stations (AQMS) in Hong Kong from December 30, 2013 to June 12, 2014 are set out in Annex II.
(2) The effects of air pollution may vary among different categories of people. This includes those susceptible to air pollution, (i.e. people with heart or respiratory illnesses, children and the elderly), outdoor workers and the general public. The AQHI webpage has provided relevant health advice to help different categories of people take precautionary measures as appropriate. In case of special incidents (for example a sandstorm or other causes) when the whole territory or individual district is suffered from persistent "serious" air pollution, the Environmental Protection Department (EPD) will work closely with relevant departments including the Hong Kong Observatory and Department of Health to assess the situation and consider adopting appropriate measures.
(3) Hong Kong's air pollution is mainly attributed to the issues from regional ozone pollution and local emissions (in particular vehicular emissions). As Hong Kong's area is only about 1 104 square km, to improve air quality, we must address the regional and local pollution sources at the same time instead of targeting on individual district alone. The Environment Bureau released "A Clean Air Plan for Hong Kong" in March 2013 to outline comprehensively the challenges Hong Kong is facing with regard to air quality and to give an overview of the relevant air quality improvement policies and measures. The key measures include reducing emissions from power plants, adopting an incentive-cum-regulatory approach to phase out pre-Euro IV diesel commercial vehicles, subsidising franchised bus companies to retrofit Euro II and Euro III buses with selective catalytic reduction devices, using roadside remote sensing equipment to spot vehicles with excessive emissions, reducing the sulphur content of locally supplied marine light diesel and mandating ocean-going vessels to use cleaner fuel while at berth in Hong Kong waters, etc. In addition, we have been joining hands with Guangdong Province to implement additional emission reduction measures, which focus on power plants and motor vehicles, to improve the air quality of the Pearl River Delta (PRD) region.
The AQHI aims to communicate the short-term health risk posed by air pollution to the general public in a simple and timely manner and enables people to have the relevant information for planning their outdoor physical activities. The AQHI can more timely and effectively reflect the health risk of air pollution than the previous Air Pollution Index (API) system.
(4) The air pollutants in Hong Kong are coming from local sources, PRD and other areas. According to a study by the Hong Kong University of Science and Technology commissioned by EPD in 2012, about 60 per cent to 70 per cent of the fine suspended particulates measured during wintertime come from sources outside Hong Kong. On the other hand, ozone is mainly a regional smog pollution problem while nitrogen dioxide is mainly formed by photochemical reaction of nitrogen oxides (NOx) emitted from local sources with ozone in the air.
As for the air pollutants of Hong Kong, the major sources include public electricity generation, navigation, road transport, etc. Their emissions in 2012 are set out in Annex III.
(5) & (6) Days with AQHI levels higher than normal are usually recorded on days with light wind and sunny conditions and under the influence of continental airstream. Ozone and photochemical smog are gradually formed under sunlight in the whole region by the photochemical reactions of NOx and volatile organic compounds emissions from the upwind source regions. As Tung Chung is near the estuary of the Pearl River, it is therefore more susceptible to regional ozone. Also, when regional ozone occurs, NOx, which is mainly emitted from vehicles, will react with ozone in urban areas (especially at roadside), to form nitrogen dioxide, resulting in a higher level of the AQHI.
Prior to planning of infrastructural facilities by the Government, the Environment Impact Assessment study must be conducted for all designated projects under the Environmental Impact Assessment Ordinance to assess their impacts on the environment. One of the assessment criteria is the compliance with the Air Quality Objective stipulated in the Air Pollution Control Ordinance.
(7) At present, the monitoring network in Hong Kong comprises 12 general AQMS and three roadside AQMS. The 12 general AQMS cover the main districts in Hong Kong and reflect the overall air pollution situation in districts with different types of development in Hong Kong. They serve as a reliable basis for developing our air quality management strategy and provide the public with representative air quality information. The three roadside AQMS (i.e. Causeway Bay, Central and Mong Kok) are located in the busiest streets of urban areas with very high vehicular and pedestrian flows and surrounded by tall buildings. They reflect adequately the roadside air quality of places with heavy vehicular and pedestrian traffic.
The EPD will review regularly the need for revising the air quality monitoring network, including establishing new AQMS. We are now preparing to set up a general AQMS in Tseung Kwan O which is expected to start operation by the end of 2015.
Ends/Wednesday, June 25, 2014
Issued at HKT 12:35
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