AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Characteristics of Ambient Aerosol at a Suburban Site in Hong Kong During Springtime Using Aerosol Mass Spectrometry
BERTO LEE, Yong J. Li, Chak K. Chan, Jian Zhen Yu, Peter Louie, Hong Kong University of Science and Technology
Abstract Number: 205 Working Group: Urban Aerosols
Abstract As a part of the Pearl River Delta (PRD), the Hong Kong Special Administrative Region (HKSAR) has been experiencing aggravating air pollution problems over the past few decades. Measurements of ambient particulate matter (PM2.5 and PM10) in Hong Kong in the past have been almost exclusively based on filter sampling and off-line analysis. We present here the first time application of a real-time PM characterization instrument, a High-Resolution Time-Of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS), at a suburban site in Hong Kong during spring 2011. Measured non-refractory PM1 (NR-PM1) concentrations are well below those observed in other areas of the Pearl River Delta Region (Huang et. al, 2011, He et. al, 2011) as well as other Chinese cities (Huang et. al, 2010, Sun et al., 2010). Sulfate and organics were identified as the dominant species, with the former contributing to more than 50% of NR-PM1 at the sampling site. Analysis of high resolution organic spectra by Positive Matrix Factorization yielded 3 distinct Organic Aerosol (OA) components, Hydrocarbon-like organic aerosol, Semi-volatile organic aerosol and low-volatile organic aerosol (HOA, SV-OOA, LV-OOA) with characteristic diurnal profiles. Back trajectory analysis indicates that elevated total NR-PM1 mass concentrations and contributions of organics during the sampling period were mainly associated with northerly continental and north-easterly coastal air masses. Instrumental inter-comparison with a collocated MARGA (Monitor for Aerosols and Gas in Ambient Air) operated by the Environmental Protection Department of the HKSAR government and a Sunset thermo-optical ECOC analyzer were performed, with good agreement for organics, sulfate and ammonium, while a considerable underestimation of nitrate by AMS as compared to MARGA was observed.
The work was supported by the University Grants Committee (Special Equipment Grant, SEG-HKUST07) and the Environmental Conservation Funds (ECF) of Hong Kong (project number: ECWW09EG04).