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Air quality in Hong Kong

LCQ20: Air quality in Hong Kong

Hong Kong (HKSAR) – Following is a question by the Hon Kam Nai-wai and a written reply by the Secretary for the Environment, Mr Edward Yau, in the Legislative Council today (January 11):


An environmental group has conducted a study on Hong Kong’s air quality and Air Quality Objectives (AQOs), pointing out that according to the ranking of cities released by the World Health Organisation (WHO) in respect of the value of fine suspended particulates (i.e. particulates of a size smaller than an aerodynamic diameter of 2.5 microns) (PM2.5) in the air, Hong Kong is ranked the 559th (i.e. the bottom eighth) among 566 cities. (this study was done by Clear the Air) In this connection, will the Government inform this Council:

(a)whether the existing three roadside monitoring stations and 11 general monitoring stations in Hong Kong had collected data on PM2.5 in each of the past 10 years; if they had, of the details; if not, the reasons for that, and whether such data will be collected continuously in the future;

(b)whether it knows, according to the statistical data of WHO and other international institutions or organisations, how the values of various types of air pollutants (e.g.

PM2.5, respirable suspended particulates, sulphur dioxide and nitrogen dioxide, etc.) in Hong Kong compare with the relevant values in various cities in the world (e.g. of its ranking among various cities); if it knows, of the details;

(c)given that the current AQOs of Hong Kong do not cover PM2.5, whether the Government will include the value of PM2.5 in the AQOs, and proactively release the relevant data to the public; if it will, of the details and the specific timetable; if not, the reasons for that; and

(d)given that on May 19 and June 8 last year, the Chief Executive and the Secretary for the Environment respectively said at the Chief Executive’s Question and Answer Session and the meeting of this Council that announcements on the new AQOs would be made within 2011 for discussion by the whole community, but so far the Government has not yet put forward the new AQOs, of the reasons for that; of the justifications for the Chief Executive to indicate at the Question and Answer Session that announcements would be made, and the progress and details of updating the AQOs at that time; whether there was any subsequent change regarding the work progress and details so that it could not make the announcements; if so, of the present work progress, details and timetable; whether the Government will require the relevant politically appointed officials to assume political responsibility for failing to put forward the new AQOs within 2011 as the Chief Executive had mentioned?



Hong Kong neighbours the rapidly developing Pearl River Delta (PRD) region, where the levels of suspended particulates are generally higher than that in Europe and America.To alleviate the pollution problem of particulate matters, the Government has been working with Guangdong Provincial Government on a regional air quality management plan to reduce emissions of the PRD region and Hong Kong.The measures include retrofitting power plants with emission reduction devices, phasing out the highly polluting industrial facilities in the PRD, tightening the vehicle emission and fuel standards, etc.These efforts are gradually bearing fruit as the regional particulates concentrations have been decreasing in recent years.Between 2005 and 2010, Hong Kong¡¦s annual fine suspended particulates (PM2.5) concentrations have been reduced by 26%.We will continue to collaborate with the Guangdong Provincial Government on emission reduction measures to further reduce the levels of particulates and other pollutants in Hong Kong.

On the questions raised by the Hon Kam, I would like to reply as follows:

(a)To understand the situation of PM2.5 in Hong Kong, we have started monitoring the pollutant in 1999 at three of the general air monitoring stations at Tap Mun, Tung Chung and Tsuen Wan together with the Central roadside station.The Yuen Long general station was later added in 2005.By the end of 2011, we have completed the installation of PM2.5 samplers in all the other monitoring stations in Hong Kong.We are now testing the samplers and expect that they will be in full operation in the first quarter of this year.

(b)Many cities, particularly those in the developing regions, have yet to monitor PM2.5 on a regular basis.The WHO collates PM10 and PM2.5 data of various cities and provides them on its website.However, the WHO also points out the limitations in comparing these particulate data of different cities because of the differences in the positioning of monitoring stations, measurement methods and quality control requirements on the measurements, etc.

According to a study by the Hong Kong University of Science and Technology in 2005, some 60% of the suspended particulates in our air could have come from regions outside Hong Kong (including PRD region and regions outside PRD) on an annual basis, and the contribution of regional background pollution to our particulate concentrations could be even higher at around 70% during the winter. Due to strong influence from regional background pollution, the levels of suspended particulates in Hong Kong are generally higher than cities in Europe and America, but are on a par with cities in the neighbouring regions such as Taipei and Seoul.

(c)The Government has proposed in the public consultation document on Air Quality Objectives Review to introduce a set of new objectives for PM2.5.

After taken into consideration the WHO guidelines and the unique situation of Hong Kong under which particulates concentrations are strongly influenced by regional factors, we propose that Hong Kong should, as a start, adopt WHO’s Interim Target-1 for PM2.5 annual and 24-hour standards, i.e. 35 ug/m3 and 75 ug/m3 respectively, as the PM2.5 objectives.We have also been providing our PM2.5 monitoring results to external parties.

(d)Updating of AQOs is not so much about changing the limit values as implementing a series of related improvement measures so as to attain the ultimate goal of air quality improvement. The Government is endeavoured to implement air quality improvement measures that are generally supported by the community, including tightening from 2015 onwards the emission caps on the power sector by 34% to 50% as compared to those for 2010; subsidising the early replacement of Euro II diesel commercial vehicles; carrying out with franchised bus companies a trial of retrofitting on Euro II and III buses with Selective Catalytic Reduction devices; funding franchised bus companies to try out hybrid buses and electric buses; setting up a $300 million pilot Green Transport Fund; introducing legislation to promote energy efficiency for electrical appliances and buildings; setting up the Kai Tak district cooling system, etc. On the other hand, some improvement measures, such as changing the fuel mix for power generation, rationalisation of bus routes, etc ., which involve complex issues and have far-reaching implications, would require detailed study and comprehensive planning.The Government is now working on the final proposal to update the AQOs for submission to the Legislative Council for deliberation as soon as possible.

Source: HKSAR Government

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