Re ECF Project: 2009-04

Project Title: Air quality in Hong Kong: A supersite program for real-time characterization of Particulate Matter (PM) in Hong Kong’s air

Applicant: Prof. Chak K. CHAN of The Hong Kong University of Science and Technology

Total Approved Grant: $6,609,000

Duration: 2/7/2010 to 1/7/2014

Project Status/Remarks: Completed

Scope:
The objectives of the proposed program are:

  • to develop a supersite program that will integrate real-time measurements and characterization of PM and VOC with existing EPD sites for air quality studies in HK;
  • to evaluate, compare, and deploy modern measurement methods on PM at selected strategic sites;
  • to describe relationships among emissions, meteorology, and atmospheric chemistry that cause excessive concentrations and how these relationships vary over time;
  • to quantify source contributions by time of day and time of year;
  • to determine limiting precursors for secondary PM2.5 formed from directly emitted SO2, NOx, VOC, and NH3 and how these precursors vary over time; and
  • to determine the water uptake of PM and determine how it affects visibility.

Summary of the Findings/Outcomes:
a. Overwhelming majority (>75%) of the PM observed are secondary in nature. They are likely transported from outside HK.
b. Nitrate, much less emphasized than sulfate in the past, can be more abundant than sulfate and can account for up to 20% of PM2.5 during nitrate episodes, especially in winter.
c. Cooking emissions contribute more to organic aerosol in Mong Kok than traffic does.
d. The inclusion of representative size distribution of aerosols, volatility basis set of organic aerosols and the aqueous phase NO2 oxidation of SO2 have significantly improved the model predictions of PM2.5 and its compositions can be used for forecasting.
e. Remote sensing techniques have matured and provided reliable surface PM data via AOD measurements.
f. Roadside PM was influenced by different sources during the four seasons.