A study to review HK AQO | Environmental Protection Department

A Study to Review Hong Kong's Air Quality Objectives

The Environmental Protection Department had, in June 2007, commissioned a comprehensive study to review Hong Kong's Air Quality Objectives (AQOs) and develop a long-term air quality management strategy. We completed the Study in mid 2009, the findings of which are now provided in the Consultation Document and the final report in detail.

The Director of Environmental Protection, Ms Anissa Wong Sean-yee (second left), and Assistant Director of Environmental Protection, Mr Tse Chin Wan (first left), are pictured with the representatives of the consultant after signing the agreement for the study to review Hong Kong's Air Quality Objectives and develop a long-term air quality management strategy.

The study examined the latest findings on review of air quality standards by the World Health Organisation, the European Union and the United States. It also considered factors including protection of public health, cost effectiveness, society's expectation, maturity of the technologies needed, time required for introducing the measures, the need to work with the Mainland as well as impacts on other policy areas such as energy, transportation, industrial development, urban planning and conservation for devising a new set of AQO and a long-term air quality management strategy and measures for Hong Kong.

The review included a thorough public consultation and engagement process. To ensure that the study would be properly conducted, we had set up an Advisory Panel on Review of the Air Quality Objectives and Development of a Long Term Air Quality Strategy to guide the study. The Advisory Panel comprised members from the Advisory Council on the Environment, experts from different sectors, academics of relevant disciplines and representatives from relevant policy bureaux of the Government. The Government will finalize the new AQO and the required long-term strategy on air quality management after carrying out a comprehensive public engagement on the Air Quality Objectives review.

Objectives of the Study

The objective of the Study was to assess the need for and the implications of revising Hong Kong's AQO as well as to identify options and propose alternative strategies and plans needed for achieving the revised AQO. Findings and options identified would be used for a comprehensive public engagement process for finalising action on the new AQO and the required long-term strategy on air quality management.

Scope of the Study

The Study assessed the need for and the implications of revising Hong Kong's AQO as well as to identify options and propose alternative strategies and plans needed for achieving the revised AQO. The scope of the study covered the following–

(a) review and characterize the current state of air quality in Hong Kong, including the prevailing exposure levels, developing trend, major pollution sources and origins, the impacts of external and non-anthropogenic sources on Hong Kong’s air quality, as well as policies, programmes and legislation in place for controlling air pollution and the costs and implications due to air pollution;

(b) examine and make reference to the different reasoning of the WHO and the US EPA in devising their respective air quality guidelines or standards, including concrete research results on long-term and short-term health impacts;

(c) use methods including air modelling to assess air quality under different scenarios and with mitigation measures adopted; to recommend specific measures required and options available to achieve interim targets and the standards if the new WHO AQG are to be adopted; to examine in depth the need for co-operation with neighbouring cities and provinces;

(d) assess the implications of implementing the measures identified under different options, including economic and social costs, the time required for introducing the measures, the need to work with the Mainland and other air quality management authorities outside Hong Kong as well as impacts on other policy areas such as energy, transportation, industrial development, urban planning and conservation;

(e) derive practicable options to revise Hong Kong’s AQO, including whether it is necessary to have different targets for roadside air quality, and to identify strategies and measures required in the form of action plan to achieve the revised AQO, with implications identified for each option, so as to facilitate public participation and comments; and

(f) review the need and means to harmonize air quality monitoring data and air pollution indices with other economically advanced cities to facilitate fair comparison.

Consultations Forums

The Environmental Protection Department had conducted a number of consultation forums in relation to the review of Hong Kong's AQO. You can access the presentation materials and the ensuing discussions at the links given below:

2007-12-18 Consultation Forum for the Professionals (in English only)

2008-01-31 Consultation Forum for the General Public (mainly in Chinese)

2009-03-20 Consultation Forum for the General Public (mainly in Chinese)

Study Reports

The review study has been completed. Please click below the final report and executive summary for the findings of the review study.

Final Report and Executive Summary

International Developments on Air Quality Objective (AQO) Review

We have been monitoring the international developments on review of air quality standards and objectives with a view to examining the need for revising Hong Kong's AQOs from a scientific perspective, taking into account local circumstances. Recent scientific research findings suggest that particulate matters smaller than 2.5 microns have more direct health effects than those of larger sizes. Moreover, the concentration levels of air pollutants capable of affecting human health may be lower than those indicated in previous studies. In view of such findings, in recent years, a number of countries including the United States of America (US), the Member States of the European Union (EU) and the World Health Organisation (WHO) have been examining the need for introducing a new set of air quality standards for particulate matters smaller than 2.5 microns (i.e. PM2.5) and revising the current air quality guidelines and standards.

The WHO announced in October 2006 an updated set of Air Quality Guidelines (AQGs). The new AQGs provide a scientific basis for supporting the development of air quality policies and management strategies in various parts of the world to protect human health. Owing to the stringency of the new AQGs, the WHO has recommended interim targets in the new guidelines for countries to improve their air quality progressively.

The WHO clearly points out that the actual air quality standards set in each country will vary according to the approach adopted for balancing health risks, technological feasibility, economic considerations and various other political and social factors. It also advises that governments should consider their own local circumstances carefully before adopting the new AQGs as statutory standards.

The government of the United Kingdom (UK), in its consultation document published in April 2006, considered it impracticable to fully achieve the air quality standards recommended by the WHO. The UK estimated that it could only meet the standards for some air pollutants, e.g. particulates, by 2050. In July 2007, the UK published their latest Air Quality Strategy introducing new annual average and background exposure reduction for PM2.5 to be achieved by 2020. The US Environmental Protection Agency (EPA) announced new air quality standards for particulate matters and ozone in late September 2006 and mid-March 2008, respectively. These new standards are less stringent than those in the new WHO AQGs and the years for meeting the targets range from 2014 to 2031. In May 2008, the EU finalised a directive on ambient air quality which includes a PM2.5 annual average standard to be achieved by 2015. Again, this new PM2.5 standard is less stringent than that in the new WHO AQGs.