Comparison of Black Carbon Aerosols in Urban and Suburban Areas of Shanghai
-
摘要: 为了探讨上海市区和郊区黑碳气溶胶质量浓度、分布以及来源和输送等特征,利用上海浦东 (市区) 和东滩 (郊区河口湿地)2007年12月—2008年11月的黑碳气溶胶小时平均质量浓度数据,对比分析了两地黑碳气溶胶浓度在不同时间尺度上的变化特征以及气象要素对黑碳质量浓度的影响。结果表明:观测期间浦东和东滩两地黑碳气溶胶小时质量浓度平均值分别为3.8 μg·m-3,1.7 μg·m-3。两地黑碳气溶胶浓度具有类似的季节变化特征,均为冬季较高、夏季较低;同时浦东黑碳气溶胶浓度日变化呈现出明显的双峰结构,并具有显著的周末效应,体现了局地人为源排放的影响。受源排放影响为主的市区与受输送影响为主的郊区,黑碳气溶胶浓度在不同风向上与风速的关系表现出不同特征。Abstract: Black carbon (BC) aerosols influence climate by absorbing incoming solar radiation resulting in a warming effect with large uncertainties. To better understand the anthropogenic BC pollution and its transport in the region of Shanghai, the BC mass concentrations are measured at Pudong (the urban site) and Dongtan (the suburban wetland site), during a one-year period from December of 2007 to November of 2008. The diurnal and seasonal variations of BC mass concentration and the wind-concentration relationships at two sites are compared. According to the Aethalometers, the hourly BC mass concentration of Pudong is 1.2—7.6 μg·m-3 (10%—90% percentiles), with an average value of 3.8 μg·m-3, which is significantly higher than that of Dongtan (0.1—4.3 μg·m-3, with an average of 1.7 μg·m-3). The BC concentrations show similar variation patterns at both sites in seasonal scale, with the highest concentrations usually observed in winter and the lowest concentrations in summer. However, different diurnal patterns are usually observed at different sites. The average diurnal variation measured at the urban (Pudong) site revealed a dual-peak pattern, with peaks between 09:00 and 10:00 and between 20:00 and 21:00, while the minimum values generally appear in the afternoon and midnight. The morning peaking is attributed to enhanced traffic during rush hour, while the evening rush hour combined with the collapse of convective boundary layer result in the evening peak. Additionally, pronounced "weekend effect" is observed at the urban (Pudong) site, when the average BC concentration of non-workdays is about 13% lower than that of workdays. These results indicate that the BC concentration at Pudong site is mainly influenced by the local anthropogenic emissions. In contrast, neither significant diurnal variation nor significant "weekend effect" is observed at the suburban (Dongtan) site, indicating that the local anthropogenic emissions at Dongtan are relatively weaker. Surface wind direction and wind speed has substantial effects on the BC concentrations. Wind could either dilute BC aerosols or transport them from other places and contribute to the measured concentration, depending on different wind directions and speeds. Different characteristics of wind-concentration relationships are observed for urban and suburban areas in which the BC concentrations are mainly influenced by the local emissions and by the regional pollutant transport, respectively.
-
Key words:
- Shanghai;
- black carbon;
- aerosol;
- air quality
-
图 3 黑碳气溶胶质量浓度月变化 (长方形框中的虚横线表示月平均值;实横线表示中位数;长方形上、下边分别表示75%和25%分位数;竖线上、下端分别表示95%和5%分位数)
Fig. 3 The monthly mass concentrations of black carbon aerosols
(dashed and solid horizontal lines in the boxes represent mean and median values, respectively; the upper and lower sides of the boxes represent the 75% and 25% percentiles; while the upper and lower points of the vertical lines are 95% and 5% percentiles)
图 6 黑碳气溶胶质量浓度和风向及风速的关系
(半径表示风速,单位:m·s-1;彩色填充区代表黑碳气溶胶质量浓度;黑色实线代表风的频次)
Fig. 6 The relationship of BC mass concentration to wind direction and speed
(the radius represents wind speed, unit: m·s-1; the color represents BC mass concentration; the solid black line shows the frequencies of wind from different directions)
-
[1] Charlson R J, Schwartz S E, Hales J M, et al. Climate forcing by anthropogenic aerosols. Science, 1992, 255: 423-430. doi: 10.1126/science.255.5043.423 [2] Ramanathan V, Crutzen P J, Kiehl J T, et al. Atmosphere-aerosols, climate, and the hydrological cycle. Science, 2001, 294: 2119-2124. doi: 10.1126/science.1064034 [3] Dockery D W, Pope C A, Xu X P, et al. An association between air pollution and mortality in 6 United States cities. New Engl J Med, 1993, 329: 1753-1759. doi: 10.1056/NEJM199312093292401 [4] 温玉璞, 徐晓斌.青海瓦里关大气气溶胶元素富集特征及其来源.应用气象学报, 2001, 12(4): 400-408. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20010455&flag=1 [5] 徐祥德, 丁国安, 卞林根.北京城市大气环境污染机理与调控原理.应用气象学报, 2006, 17(6):815-828. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=200606129&flag=1 [6] 赵春生, 彭大勇, 段英.海盐气溶胶和硫酸盐气溶胶在云微物理过程中的作用.应用气象学报, 2005, 16(4):417-425. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20050452&flag=1 [7] Ramanathan V, Carmichael G. Global and regional climate changes due to black carbon. Nature Geosci, 2008, 1: 221-227. doi: 10.1038/ngeo156 [8] Dusek U, Reischl G P, Hitzenberger R. CCN activation of pure and coated carbon black particles. Environmental Science & Technology, 2006, 40: 1223-1230. http://europepmc.org/abstract/MED/16572779 [9] Kaärcher B, Moöhler O, DeMott P J, et al. Insights into the role of soot aerosols in cirrus cloud formation. Atmos Chem Phys, 2007, 7: 4203-4227. doi: 10.5194/acp-7-4203-2007 [10] 张华, 王志立.黑碳气溶胶气候效应的研究进展.气候变化研究进展, 2009, 5(6):311-317. http://www.cnki.com.cn/Article/CJFDTOTAL-FTJS201001003.htm [11] 秦世广. 我国大陆地区大气黑碳气溶胶观测研究. 北京: 中国气象科学研究院, 2001. [12] Hansen A D A, Novakov T. Aerosol black carbon measurements over the western Atlantic Ocean. Global Biogeochemical Cycles, 1988, 2(1): 41-45. doi: 10.1029/GB002i001p00041 [13] Hansen A D A, Novakov T. Real-time measurement of aerosol black carbon during the carbonaceous species methods comparison study. Aerosol Science and Technology, 1990, 12: 194-199. doi: 10.1080/02786829008959339 [14] Parungo F, Nagamoto C, Zhou M Y. Aeolian transport of aerosol black carbon from China to the ocean. Atmos Environ, 1994, 28(20):3251-3260. doi: 10.1016/1352-2310(94)00164-G [15] Latha K M, Badarinath K V S. Black carbon aerosols over tropical urban environment—A case study. Atmospheric Research, 2003, 69:125-133. doi: 10.1016/j.atmosres.2003.09.001 [16] 汤洁, 温玉璞, 周凌晞.中国西部大气清洁地区黑碳气溶胶的观测研究.应用气象学报, 1999, 10(2): 160-169. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=19990255&flag=1 [17] 秦世广, 汤洁, 温玉璞.黑碳气溶胶及其在气候变化研究中的意义.气象, 2007, 27(11): 3-7. doi: 10.7519/j.issn.1000-0526.2007.11.001 [18] 李杨, 曹军骥, 张小曳, 等. 2003年秋季西安大气中黑碳气溶胶的演化特征及其来源解析.气候与环境研究, 2005, 10(2):229-237. http://www.cnki.com.cn/Article/CJFDTOTAL-QHYH200502009.htm [19] 娄淑娟, 毛节泰, 王美华.北京地区不同尺度气溶胶中黑碳含量的观测研究.环境科学学报, 2005, 25(1):17-22. http://www.cnki.com.cn/Article/CJFDTOTAL-HJXX200501003.htm [20] 杨溯, 张武, 韩晶晶, 等.上海市浦东新区秋冬季黑碳气溶胶特性.兰州大学学报 (自然科学版), 2008, 44(4): 66-70. http://www.cnki.com.cn/Article/CJFDTOTAL-LDZK200804015.htm [21] 高枞亭, 张仁健, 苏丽欣.长春秋冬季大气黑碳气溶胶的特征分析.高原气象, 2009, 28(4): 803-807. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX200904011.htm [22] 陶俊, 朱李华, 韩静磊, 等.广州城区冬季黑碳气溶胶污染特征及其来源初探.中国环境监测, 2009, 25(2):53-56. http://www.cnki.com.cn/Article/CJFDTOTAL-IAOB200902014.htm [23] 薛福民, 李娟, 黄侃, 等.塔克拉玛干沙漠黑碳气溶胶的特性及来源.中国科学 (化学), 2010, 40(5): 556-566. http://www.cnki.com.cn/Article/CJFDTOTAL-JBXK201005017.htm [24] 高润祥, 牛生杰, 张华, 等.2006年春季西北地区黑碳气溶胶的观测研究.南京气象学院学报, 2008, 31(5): 655-661. http://www.cnki.com.cn/Article/CJFDTOTAL-NJQX200805007.htm [25] 吴兑, 毛节泰, 邓雪娇, 等.珠江三角洲黑碳气溶胶及其辐射特性的观测研究.中国科学 (D辑), 2009, 39(11):1542-1553. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=jdxk200911006&dbname=CJFD&dbcode=CJFQ [26] 张瑛, 高庆先.硫酸盐和黑碳气溶胶辐射效应的研究.应用气象学报, 1997, 8(增刊): 87-91. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=yyqx7s1.011&dbname=CJFD&dbcode=CJFQ [27] 张美根, 徐永福, 张仁健, 等.东亚地区春季黑碳气溶胶源排放及其浓度分布.地球物理学报, 2005, 48(1):46-51. http://www.cnki.com.cn/Article/CJFDTOTAL-DQWX200501008.htm [28] 宿兴涛, 王汉杰.中国黑碳气溶胶分布特征与辐射强迫的模拟研究.大气科学学报, 2009, 32(6):798-806. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=njqx200906008&dbname=CJFD&dbcode=CJFQ [29] Babu S S, Moorthy K K. Aerosol black carbon over a tropical coastal station in India. Geophys Res Lett, 2002, 29: 2098. doi: 10.1029/2002GL015662/full [30] Allen G, Johnson P R S. Spatial and Temporal Aspects of Black Carbon Concentrations over the Boston Metro Area:An Update of Work in Progress. The 22nd Annual Conference of the American Association of Aerosol Research, Anaheim, CA, 2003. [31] 何书元.概率论与数理统计.北京:高等教育出版社, 2006: 252-253.