The organic and inorganic species in total suspended particulates (TSP) collected from June to December in 1998 in Hong Kong were identified by gas chromatography-mass spectrometry (GC-MS) and inductively coupled plasma-mass spectrometry (ICP-MS) to investigate the sources of Hong Kong aerosols and the mechanisms that control the chemical compositions and variations in the atmosphere. These samples were classified according to the climate: wet, dry under the influence of southerly winds from the sea (Dry-S) and dry under the influence of northerly winds from the continent (Dry-N). There were significant increases of materials from crustal, biogenic and pollution sources in the Dry-N period by a factor of 5, 4, and 2, respectively. Since the crustal tracers (e.g., Al, Fe) could be from coal flyash, the estimate of crustal material in the Dry-N period may include some materials from pollution source. Therefore, a positive correlation between crustal and pollution elements was observed. From the analysis of solvent-extractable organics (SEOC), microbial and meat cooking sources showed slight increase (1.2-fold). Higher levels of plant wax materials in the Dry-N period were probably due to the higher wind speed during the winter monsoon. The percentage of crustal material in TSP was 47% in the Dry-N period, and only 22% in the wet season and the Dry-S period. Plant wax materials (biogenic source) had a higher percentage in the Dry-N period (39% of SEOC) while microbial and meat cooking sources accounted for 49% of SEOC in the wet season. This study revealed that wind direction and precipitation had a significant influence not only on the concentrations but also on the chemical compositions and sources of Hong Kong aerosols.
Lake areas in Chinese urban fringes are under increasing pressure of urbanization. Consequently, the conflict between rapid urban sprawl and the maintenance of water bodies in such areas urgently needs to be addressed. An integrated GIS-based analysis system (IGAS) for supporting land-use management of lake areas in urban fringes was developed in this paper. The IGAS consists of modules of land-use suitability assessment and change/demand analysis, and land evaluation and allocation. Multicriteria analysis and system dynamics techniques are used to assess land-use suitability and forecast potential land-use variation, respectively. Cost approximation and hypothetical development methods are used to evaluate land resource and market values, respectively. A case study implementing the system was performed on the Hanyang Lake area in the urban fringe of Wuhan City, central China, which is under significant urbanization pressure. Five categories of suitability were investigated by analyzing 11 criteria and related GIS data. Two scenarios for potential land-use changes from 2006 to 2020 were predicted, based on a systematic analysis and system dynamics modeling, and a hierarchical land-use structure was designed for the conservation of aquatic ecosystems. The IGAS may help local authorities better understand and address the complex land-use system, and develop improved land-use management strategies that better balance urban expansion and ecological conservation. (c) 2007 Elsevier B.V. All rights reserved.
Motor vehicle (MV) emissions and ambient particle concentrations under a variety of situations were studied in Toronto and Vancouver, Canada. Petroleum biomarkers (i.e., hopanes and steranes) were used to determine the fraction of fine particle organic carbon (OC) attributed to primary particles in MV exhaust. Source profiles obtained from a tunnel and from direct tailpipe emissions were applied to ambient measurements at locations ranging from rush hour traffic to a regional background site. The greatest amount of MV OC, 4.0 mu gC m(-3) out of 9.1 mu gC m(-3) or 43%, was observed 75 m south of a commuter highway during a period that included morning rush hour. Monthly estimates of MV-OC were determined for a downtown Toronto monitoring site for 2 years. Total OC concentrations were greater in the summer, due to secondary OC, but the amount of MV-OC did not exhibit a strong seasonal pattern. However, on a per cent basis, MV contributions from primary OC emissions were greatest in the winter (15-20%) and smallest in the summer (10-15%) with a two-year average of 14% of the OC or about 5% of the PM2.5. (c) 2006 Elsevier Ltd. All rights reserved.