Multi-Expertise Collaboration 

on regional ozone & photochemical smog control

HKUST Institute for the Environment has been collaborating with the atmospheric research teams from HKUST, The Chinese University of Hong Kong (CUHK), City University of Hong Kong (CityU) and The Hong Kong Polytechnic University (PolyU), as well as the international experts and atmospheric research teams including those in Guangdong and Macaoto to study and develop science-based regional ozone and photochemical smog control strategies led by the HKSAR Environmental Protection Department (HKEPD).

Combination of multi-disciplinary expertise with cutting-edge technology is targeted for improving the quantitative understanding of different emission sources contributing to the formation of ozone and smog in the atmosphere, their transport pathways, and their enroute transformation processes over Hong Kong and the Guangdong-Hong Kong-Macao Greater Bay Area (GBA).

Group photo
The large-scale collaboration involves local and international experts and atmospheric research teams. 


The multi-year collaboration efforts include -

  1. the setting up of multiple real-time research-grade instruments at selected sites around Hong Kong to continuously monitor the ground level variations of the reactive organic precursors significant for ozone and smog formations;
  2. the setting up of a multi-site LIDAR (Light Detection and Ranging) network to continuously monitor the 3-dimensional variations of wind, ozone and particulates and their impact on air pollution over Hong Kong;
  3. the setting up of comprehensive air-borne, sea-borne and land-based sampling capabilities to be deployed under short-notice during ozone episodes;
  4. the setting up of a “Gold Standard Volatile Organic Compounds (VOC) Analysis Lab” to allow precise and world-class VOC analyses to support the enhanced VOC sampling and source apportionment needs;
  5. the use of state-of-the-art photochemical models to integrate and reconcile the various observations, and to access the impact of different ozone and smog control strategies.

In addition, the research results and progress are closely monitored by an expert scientific steering committee comprised of leading atmospheric researchers from Hong Kong and the Mainland, to make sure that the best science is used to formulate the final ozone and smog control strategies.

Complexity of the ozone problem

Unlike other pollutants (e.g., SO2, CO) that are emitted directly into the atmosphere from specific sources, ozone is NOT directly emitted, but instead, it is formed in the atmosphere through complex photochemical reactions involving its reactive precursors including NO2 and volatile organic compounds (VOC). The reactive VOC precursors are a family of hundreds of chemical compounds released, often at trace levels, from a wide range of man-made and natural sources.

Moreover, because of the different industrial mixes and the natural environment in different regions, the composition of the reactive precursors could be very different from one place to another. Furthermore, the ambient concentrations of these reactive species are often very low (at parts-per-trillion levels), and hence their accurate measurements require the use of advanced (research grade) instruments, supported by experienced researchers following carefully designed sampling and analysis protocols.


Aerosol, ozone and wind LIDAR in HKUST Air Quality Research Supersite


World-class VOC laboratory equipped with cutting-edge instruments for ambient and source characterization of VOCs and to serve as a benchmarking laboratory to support the air quality monitoring network in Hong Kong and GBA.

Key components of the current research effort

  1. The first part of the research effort is the continuous monitoring of the atmospheric composition of the reactive organic precursors. This includes the operation of advanced continuous mass-spectrometry instruments by research teams led by Prof. Zhe WANG (HKUST), Prof. Jianzhen YU (HKUST), Prof. Chak Keung CHAN (CityU), Prof. Kin-Fai HO (CUHK), and Prof. Shun Cheng LEE (PolyU), at multiple locations (urban, rural, background, and at the top of Tai Mo Shan) to fully characterize the detailed composition of the ambient atmosphere around Hong Kong.
  2. Atmospheric transport is three-dimensional. Besides quantifying the atmospheric composition on the ground, a good understanding of the atmospheric transport in the surface boundary layer above the ground is also very important. Hence, the second part of the research effort is the operation of LIDARs led by Prof. Changqing LIN (HKUST) to continuously measure the vertical variations of wind, ozone, and particulate matter (PM) at multiple locations across Hong Kong.
  3. Ground and LIDAR measurements can provide continuous information at specific points, but the spatial coverage is still limited. Hence, the third part of the research effort is to conduct much more comprehensive air, sea, and land measurements during episodic events. These include the advanced real-time sensor-based air monitoring and collection of multiple air samples using helicopters from the Government Flying Services led by Prof. Zhi NING (HKUST) and Prof. Dasa GU (HKUST), aboard marine vessels led by Prof. Zhe WANG (HKUST), and through enhanced 80-point simultaneous coordinated gridded sampling conducted in Hong Kong, Macao and Guangdong.
  4. The enhanced sampling implies a large increase in the need for precise VOC analyses, not just for the current research effort in Hong Kong, but also for understanding and qualifying the rising ozone problem in the GBA in the future. Hence, the fourth part of the research effort is the support by HKEPD and the Innovation Technology Commission (ITC) for the establishment of a Gold Standard VOC lab in Hong Kong led by Profs. Alexis LAU and Dasa GU (HKUST). This lab is targeted to serve as a reference lab to help enhance the region’s capability in VOC measurements and analyses.
  5. The observational data generated by the routine and episodic measurements shall be analyzed by the initial research teams, as well as the source apportionment team led by Prof. Zibing YUAN (South China University of Technology, Guangzhou) to help identify the dominant sources contributing to the release of the reactive precursors.
  6. At the same time, the observations will also be used by the modeling team led by Prof. Jimmy FUNG (HKUST) to fine-tune and validate the air quality model for use in ozone and smog studies over Hong Kong and the GBA. Subsequently, informed by the source apportionment studies, the modeling team shall also conduct scenario analyses to evaluate the performance of different emission control strategies in the reduction of ozone pollution in Hong Kong and the GBA.

Media Coverage