[i] All measurements of the concentration of gaseous air pollutants, i.e., sulphur dioxide, nitrogen dioxide, ozone and carbon monoxide, are to be adjusted to a reference temperature of 293Kelvin and a reference pressure of 101.325 kilopascal.
[ii] Respirable suspended particulates means suspended particles in air with a nominal aerodynamic diameter of 10 μm or less.
[iii] Fine suspended particulates means suspended particles in air with a nominal aerodynamic diameter of 2.5 μm or less.
Air Quality Management in Hong Kong
The overall policy objective for air quality management in Hong Kong is to achieve as soon as reasonably practicable and to maintain thereafter an acceptable level of air quality to safeguard the health and well being of the community, and to promote the conservation and best use of air in the public interest. In this regard, we put in force an updated Hong Kong’s AQOs on 1 January 2014 to further protect public health.
The new AQOs, which are benchmarked against a combination of interim and ultimate targets under the World Health Organization's Air Quality Guidelines, are broadly comparable to the air quality standards adopted by the European Union and the United States. We will also review the AQOs at least once every five years with a view to tightening the standards where practicable.
To attain the new AQOs, the Government has put forward a wide range of new air quality improvement measures. In addition, the Hong Kong Special Administrative Region (HKSAR) and Guangdong Provincial Governments endorsed in November 2012 a new set of regional emission reduction targets/ranges for 2015 and 2020 respectively. Meeting the emission reduction targets would enable the ambient air quality of Hong Kong to meet broadly the new AQOs by 2020.
Download the Table of AQO
Air Quality Compliance Status
Air Pollution Control Strategy
WHO Air Quality Guidelines for Particulate Matter, Ozone, Nitrogen Dioxide and Sulphur Dioxide, Global Update 2005
Air Quality of Hong Kong
Air Quality Health Index
Air Quality Reports
Air Quality Objectives of Other Countries