C 1–C 8 volatile organic compounds in the atmosphere of Hong Kong: Overview of atmospheric processing and source apportionment

H Guo,K.L So,I.J Simpson,B Barletta,S Meinardi,D.R Blake

doi:10.1016/j.atmosenv.2006.10.011

H Guo, K.L So + Show 4 more

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https://doi.org/10.1016/j.atmosenv.2006.10.011

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Journal: Atmospheric Environment	Publication Date: Dec 14, 2006
Citations: 220	License type: cc-by

Affiliation: University of California, Irvine

Abstract

We present measurements of C 1–C 8 volatile organic compounds (VOCs) at four sites ranging from urban to rural areas in Hong Kong from September 2002 to August 2003. A total of 248 ambient VOC samples were collected. As expected, the urban and sub-urban sites generally gave relatively high VOC levels. In contrast, the average VOC levels were the lowest in the rural area. In general, higher mixing ratios were observed during winter/spring and lower levels during summer/fall because of seasonal variations of meteorological conditions. A variation of the air mass composition from urban to rural sites was observed. High ratios of ethyne/CO (5.6 pptv/ppbv) and propane/ethane (0.50 pptv/pptv) at the rural site suggested that the air masses over the territory were relatively fresh as compared to other remote regions. The principal component analysis (PCA) with absolute principal component scores (APCS) technique was applied to the VOC data in order to identify and quantify pollution sources at different sites. These results indicated that vehicular emissions made a significant contribution to ambient non-methane VOCs (NMVOCs) levels in urban areas (65±36%) and in sub-urban areas (50±28% and 53±41%). Other sources such as petrol evaporation, industrial emissions and solvent usage also played important roles in the VOC emissions. At the rural site, almost half of the measured total NMVOCs were due to combustion sources (vehicular and/or biomass/biofuel burning). Petrol evaporation, solvent usage, industrial and biogenic emissions also contributed to the atmospheric NMVOCs. The source apportionment results revealed a strong impact of anthropogenic VOCs to the atmosphere of Hong Kong in both urban/sub-urban and rural areas.

Highlights

In 2002, there were over 524,000 vehicles registered in Hong Kong (TD, 2003), from which 8360 tonnes of non-methane volatile organic compounds (VOCs) (NMVOCs) were emitted (EPD, 2006)
The average VOC levels at Tung Chung (TC) and Central/ Western (C/W) were similar except butanes, and in between the two extremes of Tap Mun (TM) and Yuen Long (YL)
The highest VOC average levels at YL are likely attributed to strong local urban activities and regional pollutants from the rapidly developing

Summary

Introduction

(NRC, 1991), it is crucial to characterize the sources and distribution of VOCs in the atmosphere of Hong Kong. Hong Kong is a densely populated city situated in the rapidly developing Pearl River Delta (PRD) region of southern China. It is influenced by VOC emissions from local vehicles and regional industrial activities. Activities from power generation, marine vessels and aircraft generated 1229 tonnes of NMVOCs. A number of studies have been conducted to understand the spatial–temporal distribution of VOCs in Hong Kong (Lee et al, 2002; Ho et al, 2004; Guo et al, 2004a). The objectives of this study are to investigate the correlation of VOCs with trace gases such as CO and O3 in order to assess the sources and photochemical processes in Hong Kong and its upwind regions, and to identify and quantify the relative contributions of emission sources to ambient VOCs using a receptor model

Environment of Hong Kong and the four monitoring sites

Measurement of VOCs and other trace gases

Results and discussion

Atmospheric processing of air masses impacting Hong Kong

Source apportionment of VOCs in Hong Kong

Summary and conclusions