【作者】 王雪梅；

【导师】 陈建民； 张人一；

【作者基本信息】 复旦大学 ， 环境科学， 2014， 博士

【摘要】 本研究通过对上海市区以及崇明岛东滩湿地大气PM2.5和PM1o为期两年观测,比较两地PM2.5和PM10的质量浓度水平及化学性质,分析大气颗粒物来源,探讨全年典型污染期大气颗粒物特征,考察长江隧桥开通对东滩湿地大气环境的影响,讨论世博会期间排放控制措施对上海大气颗粒物及区域环境的影响。此外,对上海市大气颗粒物数浓度及粒径分布、化学组成及粒径分布进行研究,分析上海持续高污染期大气颗粒物数浓度粒径分布特征,阐明灰霾及光化学烟雾事件大气颗粒物数浓度、粒径分布及化学组成。以期探究东滩湿地大气颗粒物特征,全面揭示中国东部沿海城市上海大气颗粒物污染长期变化趋势和特征,为探讨城市群与湿地大气环境的相互影响提供有力支持。本论文主要成果如下：1.上海市区与东滩湿地大气PM2.5和PM1o的质量浓度、化学性质：(1)市区PM2.5和PM1o平均质量浓度分别为27.8和48.6μg/m3,分别为世界城市均值的2.53和1.35倍；东滩湿地PM2.5和PM10平均质量浓度分别为15.8和22.1 gg/m3,超出环境空气质量PM2.5一级标准。市区与东滩PM10质量浓度季节变化显著,基本呈现相同特征,即冬季>春季>秋季>夏季。市区PM2.5浓度季节变化与PM10相同,东滩湿地PM2.5浓度季节变化与PM10略有不同。东滩湿地PM2.5/PM10值大于市区,以细颗粒物污染为主,PM2.5受市区影响较大。(2)市区水溶性离子浓度分别为PM10和PM2.5质量浓度的45.8%和56.6%,东滩湿地水溶性离子浓度分别为PM10和PM2.5质量浓度的55.1%和65.7%。市区水溶性离子浓度是东滩湿地的1.5-1.8倍。SO42-、NO3-、NH4+是最主要的三种离子,共占复旦PM2.5和PM1o总水溶性离子浓度的88.9%和80.9%,占东滩PM2.5和PM10总水溶性离子浓度的90.6%和85.7%。市区PM10中Ca2+和C1-浓度较高,PM2.5中Cl-和r的浓度较高；东滩PM1o和PM2.5中Na+与K+浓度较高,体现了海洋与生物质燃烧对东滩湿地离子成分的影响。不同季节东滩与复旦的离子粒径分布结果不同。(3)市区OC和EC浓度分别为PM1o质量浓度的16.3%和9.6%,分别为PM2.5质量浓度的21.2%和14.8%；东滩湿地OC和EC浓度分别为PM10质量浓度的15.1%和10.8%,分别为PM2.5质量浓度的20.4%和16.9%。碳质成分在细颗粒物分布较多,OC浓度远高于EC浓度,市区OC和EC浓度大于东滩湿地。不同季节东滩与复旦的OC和EC浓度粒径分布结果不同。东滩PM2.5和PM1o的OC/EC比值小于市区。2.上海市区与东滩湿地大气颗粒物来源分析：(1)基于长期采样获得的PM1o和PM2.5质量浓度与化学成分数据,计算得到市区Ca2+转换为dust和OC转换为POM的f和k值分别为0.10和1.3,东滩湿地的f和k值分别为0.05和1.4。化学质量闭合结果表明,市区PM1o中Dust贡献最大(30.0%),其次是POM(19.5%)；PM2.5中POM贡献最大(23.6%),其次是S042-(22.2%)。东滩PM1o中Dust与SO42-的贡献最大(均为22.7%)；PM2.5中S042-贡献最大(为27.5%),其次是POM(21.8%)。(2)观测期间5种后向轨迹类型(L、E、S、W、N)的比例分别为12.1%、20.3%、21.6%、6.3%、39.7%。东滩PM10和PM2.5化学成分的除dust外,总体表现为W和L类型化学成分浓度最高,呈现高污染特征；N类型的污染程度居中；E和S类型化学成分浓度最低,污染较小。市区PM10和PM2.5化学成分的除dust外,总体表现为W类型化学成分浓度最高、N和L轨迹类型交替高污染特征,与东滩湿地情况稍有不同。PM10与PM2.5中NH4+、NO3+、K+、Cl-比例最高的轨迹类型分别是L、W、L和N。PMlo中S042-比例最高的轨迹类型是S和L,PM2.5中SO42-比例最高的轨迹类型为L。东滩湿地OC和EC比例最高的轨迹类型是W和S,与市区稍有不同。(3)东滩PM2.5和PM1o的N03-/S042-值小于市区,主要是固定源的影响。收获季节PM2.5和PMl0的K+/OC值较高,生物质燃烧影响占主导。3.典型时期上海市区与东滩湿地大气颗粒物特征：(1)沙尘、生物质燃烧、灰霾和烟花爆竹集中燃放四种污染事件的PM2.5和PM10质量浓度为洁净天气的2至4倍。四种污染事件中,沙尘事件PM1o中Ca2+浓度最高、PM2.5/PM1o值最小；生物质燃烧事件PM1o与PM2.5中K+浓度最高；灰霾事件PM1o与PM2.5中总离子浓度最高,特别是SO42-、NO3-和NH4浓度；烟花爆竹集中燃放事件中C1-浓度和NO3-/SO42-的比值最高,且主要分布在粗颗粒中；生物质燃烧和灰霾事件碳质成分浓度最高。(2)上海长江隧桥开通车流量骤增对东滩PM1o和PM2.5中水溶性离子影响最大的是NH4+、NO3-、SO42-和C1-,其中PM2.5中NH4+、NO3-、SO42-和CI-分别比年同期增加了52.9%、22.3%、26.7%和25.5%,PM1o中NH4、N03-、S042-分别比年同期增加了24.8%、21.3%、12.7%,PM10中NO3-/SO42-值增加至0.95。人为污染行为对东滩湿地的大气颗粒物的特征影响大。(3)上海世博会期间大气颗粒物质量浓度均低于往年同期,东滩PM10和PM2.5中K+、NH4+、SO42-和Cl-浓度显著降低,复旦PM10和PM2.5中心和Ca2+浓度大幅降低。减排措施取得了有效结果,但区域传输对排放控制条件下的大气颗粒物污染具有较大影响。4.上海市大气颗粒物数浓度、化学组成及其粒径分布特征：(1)上海市大气颗粒物总数浓度年均值为1.12×104 cm-3,凝结核模态、埃根核模态、积聚模态颗粒物数浓度分别为1156 cm-3、7619 cm-3和2388 cm-3,颗粒物总表面积和总体积浓度分别为443 μm2/cm3和40 μm3/cm3。颗粒物总数浓度冬>春>秋>夏,与总表面积和总体积浓度季节变化规律一致。(2)2013年12月持续高污染天气占整个月份的74.2%,粒径范围100 nm-1μm的颗粒物数浓度增加幅度与污染天气同步变化,特别是总表面积浓度和体积浓度在严重及重度污染期间大幅升高。(3)水溶性离子粒径分布主要集中在0.4-2.1μm的颗粒物中,浓度峰值出现在0.7-1.1μn。NO3的粒径分布在小于2.1μm和大于5.8μm都有峰值,Ca2+和Cl-浓度峰值在5.8-10μm,K+和Na+均匀分布在各粒径范围。5.上海市灰霾和光化学烟雾事件大气颗粒物数浓度、化学组成及粒径分布：2009年灰霾天数占42.7%,其中有32.1%是重度及中度灰霾,且主要分布在冬春季节。灰霾期间的大气颗粒物数浓度为1.70×104 cm-3,是清洁天气的2倍。灰霾事件颗粒物数浓度的最大增加在0.5-1μm和1-10μm粒径范围,分别是清洁天气的17.78和8.78倍。光化学烟雾事件颗粒物数浓度的最大增加在50-100nm和100-200nm粒径范围,分别是清洁天气的5.89和4.29倍。灰霾、光化学烟雾和清洁天气的颗粒物体积浓度分别为102、49和15μm3/cm3。仅占数浓度5%的粒径大于200 nm的颗粒物却贡献了体积浓度的90%,大于1μm的颗粒物对体积的贡献达50%。灰霾、光化学烟雾和清洁天气的颗粒物表面积浓度分别为949、649和206μm2/cm3。灰霾期间90%的表面积浓度来自于粒径大于100 nm的颗粒物。随着灰霾严重程度的增加,粒径小于50nm的颗粒物数浓度减小,50-200 nm和0.5-1μm的颗粒物数浓度增加。灰霾天气颗粒物数浓度日变化显示双模态特征。灰霾事件所有的可溶性离子浓度增加,其中NH4+、SO42-、NO3增加最多,其次是Na+、K+、Ca2+、Cl-。灰霾和光化学烟雾事件中离子的粒径分布特征完全不同。更多还原

【Abstract】 Weekly samples of PM2.5 and PM10 were collected at two sites, Fudan and Dongtan, in Shanghai from October 2008 to November 2010. Fudan site situated in urban area and Dongtan site located in the international important wetland inside Chongming Island. The mass concentration, organic carbon (OC), element carbon (EC) and water soluble ions were determined. Chemical mass closure was calculated, and then the sources of atmospheric particles were analyzed. We also examined the charicteristics of atmospheric partcles in typical polluted periods in urban and dongtan all the year, and explored the effects of Shanghai Changjiang Tunnel-bridge on atmospheric environment in Dongtan wetland, and discussed the influence of emission control on urban atmospheric particles and regional environment during Shanghai EXPO. Besides, we investigated the partcles number concentration, chemical composition and size distribution, and discussed the characterization of atmospheric particle number and size during longterm heavy pollution, particularly focused on the particle number concentration, size distribution and chemical composition during haze and photo-chemical smog episodes in Shanghai. The purpose was to explore the features of atmospheric particles in Dongtan wetland, and reveal completely the long-range variation trend of urban atmospheric particle pollution in Shanghai, the coastal mega-cities. These results could provide forceful support for dealing with atmospheric issuses of urban agglomeration.The main results in the dissertation as bellow:1. Level and chemical properties of PM2.5 and PM10 in urban Shanghai and Dongtan wetland:(1) Average mass concentration of PM2.5 and PM10 in urban were 27.8 and 48.6 μg/m3,2.53 and 1.35 times the average value of the world cities, respectively. The average mass concentration of PM2.5 and PM10 in Dongtan were 15.8 and 22.1 μg/m3, over the first grade of the Ambient Air Quality Standard. The PM10 mass showed a strong seasonal variation in urban and Dongtan wetland, and exhibited uniform chatacters, i.e., winter>spring>autumn>summer. The urban PM2.5 mass showed seasonality similar to PM10, but the seasonal change of PM2.5 in Dongtan wetland was different from PM10. The ratio of PM2.5/PM10 in Dongtan wetland was bigger than urban, and PM2.5 in Dongtan was influenced greatly by urban. (2)The total water soluble ions were 45.8% and 56.6% of the mass concentration of PM10 and PM2.5 in urban Shanghai, respectively. The total water soluble ions were 55.1% and 65.7% of the mass concentration of PM10 and PM2.5 in Dongtan wetland, respectively. The total water soluble ions concentration of urban PM was 1.5-1.8 times that of Dongtan. The three dominated ions of SO42-, NO3- and NH4+ accounted for 88.9% and 80.9% of the total soluble ions of PM2.5 and PM10 in urban,90.6% and 85.7% in Dongtan. The concentration of Ca2+ and Cl" in PM10, Cl- and K+ in PM2.5, was higher than other minor ions at urban site, but the concentration of Na+ and K+ in PM10 and PM2.5 was higher than other minor ions at Dongtan site. It showed that the influence of ocean and biomass burning on ionic species of Dongtan wetland. Ionic size distribution was different in different seasons in urban and Dongtan. (3)The concentration of OC and EC were 16.3% and 9.6% of PM10,21.2% and 14.8% of PM2.5 in urban, respectively. The concentration of OC and EC were 15.1% and 10.8% of PM10,20.4% andl6.9% of PM2.5 in Dongtan, respectively. Carbonaceous aerosol chiefly distributed in fine particles. The content of OC was higher than EC, and the concentration of OC and EC in urban were higher than Dongtan wetland. OC and EC size distribution were different in different seasons in urban and Dongtan. The ratio of OC/EC in Dongtan wetland was smaller than urban.2. Sources of atmospheric particles in urban Shanghai and Dongtan wetland: (1)The conversion factors f of OC-to-POM (particulate organic matter) and k of Ca2+-to-dust obtained from the dataset of PM10 and PM2.5 from long-term samples. The f and k value were 0.10 and 1.3 in Fudan,0.05 and 1.4 in Dongtan, respectively. Particle chemical mass closure displayed that the highest contribution of dust (30.0%), followed by POM (19.5%) in urban PM10. The major component was POM (23.6%), followed by SO42-(22.2%) in urban PM2.5. The highest dust and SO42- contribution (22.7%) were found in Dongtan PM10. SO42 (27.5%) and POM (21.8%) were major components in Dongtan PM2.5. (2)Each proportion of five backward trajactories of air mass (L, E, S, W, N) was 12.1%,20.3%,21.6%,6.3%,39.7% during the investigated period. W and L were heavy polluted types in Dongtan wetland, secondly N, then E and S. W were highest polluted types in urban, followed by N and L alternately. The highest proportion of NH4+、NO3-、K+、Cl- appeared in L, W, L, N, respectively. The highest proportion of SO42- existed in L. The highest proportion of OC and EC was W and S in Dongtan wetland, differed from that of urban. (3)The ratio of NO3-/SO42- in Dongtan wetland was smaller than urban, dominated by stationary sources. The K+/OC value in PM2.5 of harvest time was higher, greatly influenced by biomass burning.3. The features of atmospheric particles during typical periods in urban and Dongtan wetland:(1)The mass concentration of PM2.5 and PM10 in duststorm, biomass buring, haze and fireworks events were 2 to 4 times as that of clear days. The content of Ca2+ in PM10 was highest of four polluted event, and the ratio of PM2.5/PM10 was smallest in dustsrtorm. K+ was highest in biomass buring. Total soluble ions was highest, especially SO42-, NO3- and NH4+. Cl- and NO3-/SO42- was highest in fireworks, and mainly distributed in coarse particles. Cabonaceous aerosol was highest in biomass buring and haze. (3)The Shanghai Changjiang Tunnel-bridge was opened in the periods of sampling, which greatly influenced NH4+, NO3-, SO42-and Cl- of the total soluble ions in Dongtan PM by high vehicle flow. The concentration of NH4+, NO3-, SO42- and Cl" in PM2.5 increased by 52.9%,22.3%,26.7% and 25.5%, respectively, as compared to the same period of the previous year. The contents of NH4+, NO3- and SO42- in PM10 had 24.8%,21.3% and 12.7% increased. Anthropogenic pollution had tremendous impact on the atmospheric particles in Dongtan wetland. (3)The particulate concentration of during the EXPO was lower than the corresponding period of the previous year, in which K+、NH4+、SO42- and Cl-declined remarkably in Dongtan, and K+ and Ca2+ decreased sharply. Control measures achieved satisfactory results, but regional transport still had considerable affect on particulate pollution in the condition of strict emission control strategies.4. Particle number concentration, size distribution and chemical composition in urban Shanghai:(1)Annual number concentration of atmospheric particles was 1.11 × 104 cm-3, and the concenration of nucleation, Aitken, accumulation mode were 1156, 7619, and 2388 cm-3, respevtively. The total surface and volume concentration was 443 μm2/cm3 and 40 μm3/cm3. Number, surface and volume concentration had the same seasonal change, that is the maximum in winter, and then spring and autumn, the minimum is in summer. (2)The days of continued heavy pollution accounted for 74.2% of the December of 2013, in which the greatly increase of particulate number of 100 nm-1 μm was the chief cause, with high suface and volume concentration during severe pollution. (3)Soluble ions mainly distributed in the particles within range of 0.4-2.1 μm, and peak at 0.7-1.1 pm. The two peaks of NO3- presented in partilces lager than 5.8 μm and smaller than 2.1 μm. The peaks of Ca2+ and Cl- appered in 5.8-10 μm, and K+ and Na+ scattered within diameter in a fairly equal manner.5. Particle number concentration, size distribution and chemical composition during haze and photochemical smog episodes in Shanghai:The number of haze days accounted for 42.7%, of which 32.1% was severe (visibility<2 km) and moderate (2 km≤visibility<3 km) haze, mainly distributing in winter and spring. The mean particle number concentration was 1.70 x 104 cm-3 in haze, more than 2 times that of clean days. The greatest increase of particle number concentration was in 0.5-1 μm and 1-10 μm during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50-100 nm and 100-200 nm during photochemical smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, photochemical smog and clean days were 102,49,15 μm3/cm3 and 949,649,206 μm2/cm3, respectively. As haze events got more severe, the number concentration of particles smaller than 50 nm decreased, but the particles of 50-200 nm and 0.5-1 μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4+, SO42- and NO3- increased greatly, followed by Na+, K+, Ca2+ and Cl-. These ions were very different in size-resolved particles during haze and photo-chemical smog episodes.更多还原