Author: Antonio Da Roza

Date: 7/8/10

Air pollutant trends and the Air Quality Objectives

In 2008, for the comparison of hourly pollutant concentrations and AQOs, concentrations of ozone were found to exceed the Air Quality Objectives in six of the fourteen monitoring stations, and concentration of sulphur dioxide is also founded to be a bit higher than the AQO in the monitoring stations of the Western districts. [1]

Comparatively, the daily concentration of nitrogen dioxide was found to exceed the Air Quality Objectives in four of the fourteen monitoring stations. [1]

In accordance with the Air Quality Objectives, the maximum pollutant concentrations are particularly serious in three stations, namely Central, Causeway Bay and Mongkok – that is, the three roadside stations. [1]

Air Pollutant trends and the World Health Organisation’s Air Quality Guidelines

With regards to SO2, 12 out of the 16 PRD/Hong Kong monitoring stations exceeded the World Health Organisation’s Air Quality Guidelines by more than 5% in 2006, and 14 out of 16 exceeded the Guidelines in 2007. [2]

Roadside concentrations of PM10 and NO2 have consistently exceeded World Health Organisation’s guidelines by roughly four times and two and a half times respectively. [2]

For O3, most of the high annual mean concentration values were measure in rural areas such as Tap Mun in HK. [2]

General trends

In the past 9 years, there has been no significant downturn in particulate pollution. [3]

Between 1997-2003, total emissions of SO2 in Hong Kong increased by 39%, whereas NOx, PM10 and VOC emissions fell by 10%, 38% and 36% respectively. [2]

On more than 75% of days in a year, people in HK are exposed to PM10 and O3 concentrations that fall within poor and average levels. [4]

See Also

  1. The Air Quality Objectives
  2. The Air Quality Objectives consultation


  1. 1.0 1.1 1.2 Air quality statistics, EPD website - last accessed 7/8/10
  2. 2.0 2.1 2.2 2.3 ‘A Price Too High: The Health Impacts of Air Pollution in Southern China’, Civic Exchange, HKU Medical Centre, Department of Community and Family Medicine, CUHK, Institute for the Environment, HKUST, June 2008 - last accessed 5/8/10
  3. ‘The Sustainable Development Council Invitation and Response Document: Clean Air-Clear Choices - Will High Air Pollution Alert Days provide an efficient path to health protection?’, Department of Community Medicine, HKU, The Air Quality Objective Concern Group - last accessed 7/8/10
  4. ‘Boomtown to gloomtown – The implications of inaction’, CLSA – Christine Loh, James Paterson, September 2006 - last accessed 5/8/10