Source apportionment of lead-containing aerosol particles in Shanghai using single particle mass spectrometry Yaping Zhang a , Xiaofei Wang a , Hong Chen a , Xin Yang a, * , Jianmin Chen a, * , Jonathan O. Allen b a Department of Environmental Science and Engineering, Fudan University, 220 Handan Road, Shanghai 200433, China b Departments of Chemical Engineering, and Civil and Environmental Engineering, Arizona State University, Tempe, AZ 85287-6006, USA article info Article history: Received 25 May 2008 Received in revised form 3 October 2008 Accepted 3 October 2008 Available online 21 November 2008 Keywords: Pb-rich particle Single particle analysis ATOFMS Source apportionment Shanghai abstract Lead (Pb) in individual aerosol particles was measured using single particle aerosol mass spectrometer (ATOFMS) in the summer of 2007 in Shanghai, China. Pb was found in 3% of particles with diameters in the range 0.1–2.0 lm. Single particle data were analyzed focusing on the particles with high Pb content which were mostly submicron. Using the ART-2a neural network algorithm, these fine Pb-rich particles were classified into eight main classes by their mass spectral patterns. Based on the size distribution, temporal variation of number density, chemical composition and the correlation between different chemical species for each class, three major emission sources were identified. About 45% of the Pb-rich particles contained organic or elemental carbon and were attributed to the emission from coal combus- tion; particles with good correlation between Cl and Pb content were mostly attributed to waste incin- eration. One unique class of particles was identified by strong phosphate and Pb signals, which were assigned to emissions from phosphate industry. Other Pb-rich particles included aged sea salt and parti- cles from metallurgical processes. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction Lead (Pb) pollution has been emphasized for decades because of its serious adverse health effects (Centers for Disease Control and Prevention, 1991). One of the major sources of Pb exposure is the airborne Pb dominated by primary emissions within the urban area (Turner and Allen, 2008). Since lead and its common compounds are solid at room temperature, most of the airborne Pb exists in the particulate phase. Aerosol particles especially those fine parti- cles, which can penetrate the membranes of the respiratory tract into lungs and enter the blood circulation (Nemmar et al., 2002; Oberdorster et al., 2004), act as the main carriers of lead. Extensive research has been carried out all over the world mostly focusing on the concentration and sources of Pb-containing aerosol particles (Wang et al., 2006; Valavanidis et al., 2006; Okuda et al., 2008). The widespread elimination of leaded gasoline, in 1975 in the United States and the mid-1980s in Europe, has dras- tically changed the sources and fluxes of Pb in the environment. The isotopic patterns showed that the origin of airborne Pb in Paris shifted from road traffic towards industrial activities, with indus- trial contributions generally greater than 50%, after phasing out leaded gasoline (Widory et al., 2004). Airborne Pb in the United States has decreased by a factor of 20 or more since 1980, and the major emission sources include aviation gasoline (for piston engine), smelters, foundries and coal combustion (EPA, 2002). In China, rapid economic growth and urban development has heavily burdened the air quality (Feng et al., 2006; Liu et al., 2008). The use of leaded gasoline was banned in 1997 starting in the large cities like Beijing, Shanghai and Guangzhou. However, high Pb levels are still widely present in the local atmosphere. The concentration of Pb in Beijing remained as high as 100– 300 ng m 3 in fine particles (PM 2.5 ) according to a 5-year program from 2000 to 2004 (Sun et al., 2006). A rapid increasing trend was revealed for Pb concentration in total suspended particles (TSP) in Beijing based on daily observations from 2001 to 2006 (Okuda et al., 2008). In Shanghai, an international metropolis near East China Sea with a population of over 17 million, high concentrations of airborne Pb were also observed several years after leaded gaso- line was completely phased out. Pb concentrations (in PM 10 ) ran- ged from 167 to 854 ng m 3 with an average of 515 ng m 3 in the winter of 2001 (Zheng et al., 2004). The average values were 369 and 237 ng m 3 in the winters of 2002 and 2003, respectively (Tan et al., 2006). Source apportionment based on Pb isotopic com- positions in airborne particles suggested that the major emissions sources in Shanghai included coal combustion, the metallurgy industry and the cement industry (Zheng et al., 2004; Chen et al., 2005; Tan et al., 2006). All the above studies on Pb-containing aerosol particles in Shanghai were carried out using off-line analysis techniques such 0045-6535/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2008.10.004 * Corresponding authors. Tel.: +86 21 55665272 (X. Yang). E-mail address: yangxin@fudan.edu.cn (X. Yang). Chemosphere 74 (2009) 501–507 Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere 转载 http://www.paper.edu.cn 中国科技论文在线