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Following is a question by the Hon Albert Chan and a reply by the Secretary for the Environment, Mr Wong Kam-sing, in the Legislative Council today (January 7):
Question:
Quite a number of members of the public have relayed to me that the air pollution problem in Tung Chung has worsened in recent years, especially during summer time. In this connection, will the Government inform this Council:
(1) of the respective numbers of times in each of the past five years, as recorded by the Tung Chung Monitoring Station, in which the concentrations of fine suspended particulates (i.e. PM2.5), ozone, sulphur dioxide, nitrogen dioxide and carbon monoxide exceeded the Air Quality Objectives or the relevant objectives, and the details of the exceedance of each type of pollutants, including the respective average and maximum extent of exceedance and concentrations;
(2) whether it has analysed the major sources of air pollutants in Tung Chung; if so, of the outcome; if not, the reasons for that; and
(3) whether measures are in place to improve the air quality in Tung Chung; if so, of the details; if not, the reasons for that?
Reply:
President,
(1) The Environmental Protection Department (EPD) operates an air quality monitoring station in Tung Chung. According to the data recorded, the air quality of Tung Chung had been improving progressively in the past five years from 2010 to 2014. Concentrations of fine suspended particulates (PM2.5), respirable suspended particulates (PM10) and carbon monoxide showed a downward trend. Sulphur dioxide and nitrogen dioxide were generally stable. Ozone, affected by the regional photochemical smog, had been on the rise.
Details are as follows:
(a) Compared the data recorded at Tung Chung Air Quality Monitoring Station in 2010 and 2014 respectively, the annual average concentrations of respirable suspended particulates, fine suspended particulates and carbon monoxide had reduced by 6 micrograms per cubic metre (mcg/m3) (13 per cent), 5mcg/m3 (17 per cent) and 196mcg/m3 (27 per cent) respectively. Those of sulphur dioxide, nitrogen dioxide and ozone had slightly increased by 1mcg/m3 (8 per cent), 1mcg/m3 (2 per cent) and 3mcg/m3 (7 per cent) respectively.
(b) From 2010 to 2013, except the 1-hour concentration of ozone, other major air pollutants in Tung Chung met the prevailing short term and long term Air Quality Objectives (AQO). During the 4-year period, the highest 1-hour average concentrations of ozone were 341mcg/m3, 312mcg/m3, 383mcg/m3 and 314mcg/m3 respectively, which were on a par with 355mcg/m3 recorded in 2014.
(c) Our new AQO came into effect in 2014. According to the data not yet fully validated, apart from the 8-hour concentration of ozone and the annual concentration of nitrogen dioxide in Tung Chung, other major air pollutants all met the new short term and long term AQOs. The annual concentration of nitrogen dioxide was at the level of 45mcg/m3, exceeding the respective limit by 5mcg/m3. The number of exceedances of the 8-hour concentration of ozone was 18, with the highest level seen at 278mcg/m3, exceeding the limit by 118mcg/m3. The highest hourly average concentration was 355mcg/m3.
For the detailed data, please see Annex.
(2) The major sources of air pollution in Tung Chung are analysed in two perspectives, namely ozone and nitrogen dioxide. First, ozone is a regional air pollution phenomenon. Ozone formed by photochemical activities under unfavourable dispersion of air pollutants such as nitrogen oxides and volatile organic compounds from pollutant emission sources in the Pearl River Delta (PRD) region. Poor dispersion of air pollutants in the PRD coupled with light northerly to north-westerly wind raise the concentration of ozone to a significant level in Tung Chung.
For nitrogen dioxide, the hourly average of Tung Chung meets the requirement of the AQOs but not its annual air quality objective. Nitrogen dioxide is mainly caused by photochemical reactions of vehicular emissions of nitrogen oxides with ozone.
(3) To improve the air quality of Hong Kong (including Tung Chung), we are committed to reducing the emission of local pollutants. The Environment Bureau released A Clean Air Plan for Hong Kong (The Air Plan) in March 2013 which sets out in detail policies and measures on improving air quality covering sea and land transport, power plants and non-road mobile machinery, etc. Meanwhile, we are stepping up our collaboration with Guangdong so as to improve the regional air quality in the PRD.
To reduce the emission of nitrogen oxides from vehicles, the key measures we launched include phasing out pre-Euro IV diesel commercial vehicles by way of a subsidy-cum-mandatory scheme, strengthening the emission control from petrol and LPG vehicles and retrofitting Euro II and III franchised buses with selective catalytic reduction devices. We have launched the ex-gratia payment scheme to phase out pre-Euro IV diesel commercial vehicles since March 1, 2014. As at the end of November 2014, the first nine months since the scheme started, about 19 800, representing about a quarter of the pre-Euro IV diesel commercial vehicles took part in the scheme and were off-road. Initiatives to strengthen the emission control for petrol and LPG vehicles have also come to force since September 1, 2014. Franchised buses are expected to have their selective catalytic reduction devices installed by the end of 2016.
To control emissions from marine vessels, a new legislation was enacted in April 2014 to tighten the sulphur limit of local marine light diesel from 0.5 per cent to 0.05 per cent. We are drafting a new legislation to mandate ocean-going vessels to switch to cleaner fuel (sulphur content not exceeding 0.5 per cent) while at berth in Hong Kong for implementation in mid-2015. In addition, we are working on a new legislation to control the emissions from non-road mobile machinery which will take effect within 2015. To reduce the emissions from power plants, the Legislative Council endorsed the Fourth Technical Memorandum for Allocation of Emission Allowances in Respect of Specified Licences in December 2014 to further tighten the emission caps for sulphur dioxide, nitrogen oxides and respirable suspended particulates from 2019 onwards by 11 per cent, 2 per cent and 7 per cent respectively as compared with the 2017 emission cap levels. The Environment Bureau is reviewing the long term fuel mix for electricity generation for Hong Kong and will review the feasibility of further tightening the emission allowances for electricity generation in 2020 and beyond in the light of the findings of the review.
Lastly, regarding the control of regional air pollution, the governments of Guangdong and Hong Kong have set emission reduction targets for 2015 and 2020 in respect of the sulphur dioxide, nitrogen oxides, respirable suspended particulates and volatile organic compounds in the PRD region for the purpose of improving the regional air quality in a sustainable manner. These measures can reduce the precursor pollutants which generate ozone and directly help to control regional ozone and photochemical smog.
Ends/Wednesday, January 7, 2015
Issued at HKT 16:56
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