Traditional Chinese Simplified Chinese Email this article
LCQ13: Fine suspended particulates

     Following is a question by the Hon Audrey Eu and a written reply by the Secretary for the Environment, Mr Edward Yau, in the Legislative Council today (January 11):


     The World Health Organisation (WHO) and many academic studies have pointed out that fine suspended particulates (i.e. particulates of a size smaller than an aerodynamic diameter of 2.5 microns) (PM2.5) have greater impact on the health of a person than respirable suspended particulates (i.e. particulates of a size smaller than an aerodynamic diameter of 10 microns).  The existing Air Quality Objectives (AQOs) in Hong Kong has not included PM2.5 as a pollutant that requires to be measured, and an indicator of the concentration of PM2.5 in the air has not been formulated.  In this connection, will the Government inform this Council:

(a) whether the Government has measured the concentration of PM2.5; if it has, of the details; whether this has been released to the public; if this has not been released, of the reasons for that; if it has not measured the concentration, of the reasons for that;

(b) whether the Government has any plan to formulate an indicator of the concentration of PM2.5; if it has, of the details; if not, the reasons for that; and

(c) when the Government will update the AQOs which have been in use for nearly 25 years?



(a) To understand the situation of fine suspended particulates (PM2.5) in Hong Kong, the Environmental Protection Department (EPD) has 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.  We have also released the relevant monitoring results to external parties.  In addition, by the end of last year, we have completed the installation of PM2.5 samplers in all 14 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) 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.

(c) 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.

Ends/Wednesday, January 11, 2012
Issued at HKT 12:40


Print this page