大气气溶胶酸度和酸化缓冲能力的分析

鉴于气溶胶本身的存在状态,无法直接测定其酸度,因而我们采用类似测定土壤酸度的方法,用一定量的水溶解气溶胶滤膜样品,得到气溶胶的水溶液,测定气溶胶水溶液的酸度和其变化,其结果扣除空白滤膜水溶液的本底后,即可得到气溶胶的酸度和酸化缓冲能力.     

厦门市气候特征变化与酸雨形成研究

对地面风场的研究表明，厦门存在局地和海陆风环流，自1955年以来年平均风速、混合层厚度均呈现下降趋势，大气污染物的水平和垂直扩散能力也呈下降趋势。降水酸度随海拔高度的变化情况表明，海陆风环流有利于酸性污染物的积累，且锋面降水过程中的光化学污染加重了降水的酸化程度。     

湖南省大气湿沉降化学研究

以湖南省1999～2001年的酸雨监测数据为基础,运用统计学和线性回归分析方法研究了位于中国中南部的重酸雨区湖南省的大气降水的酸度和化学组成的分布特征以及季节变化规律。结果表明,大气降水以SO_4~(2-)为主,占总离子量的31％,大气降水阴阳离子基本平衡。降水年平均pH值为4.86,以春季酸度最大,降水离子总量以冬季最大。研究结果同时表明,降水酸度是主要酸性离子和主要碱性离子共同作用的结果,而且([H~+]+[NH_4~+])/([SO_4~(2-)]+[NO_3~-])比值的变化能较好的反映降水过程中强酸离子的中和现象。     

泰州市降水主要特征及酸雨成因浅析

对泰州市1996年—2000年降水主要特征及酸雨成因进行了分析。结果表明,泰州市酸雨出现频率高,5年来降水pH均值均<5.6,降水酸度和酸雨出现频率无明显变化;降水中化学成分以SO42-为主,NO3-质量浓度值呈上升趋势;酸雨出现频率的季节变化规律为:冬、春季>秋季>夏季,与SO2在不同季节质量浓度变化规律较一致;酸雨的形成可能受本地大气污染物和异地大气污染物的共同影响;酸性降水的形成与气象条件有关。     

GPSM(1)灰色模型在大气降水酸度预测中的应用

介绍了ＧＰＳＭ（１）灰色模型的建模思想，并将其成功地应用于某地大气降水酸度预测，其结果与实际情况一致性很好，表明ＧＰＳＭ（１）模型预测大气降水酸度是可行的     

乌鲁木齐市降水酸度及化学特征的初步研究

降水酸度和离子平衡研究结果表明,乌鲁木齐市降水为非酸性雨,但其PH值有较明显的季节变化,降水中的SO_4~(2-)、Ca~(2+)、和NH_4~+是影响酸度的关键离子,与其他地区相比,乌鲁木齐市降水中的Ca~(2+)浓度是酸雨区(贵阳、重庆)平均值的3.50倍,是非酸雨区(北京、天津)平均值的1.86倍。可见,乌鲁木齐市降水酸度的高低,不仅取决于酸性离子浓度,而且更重要的是取决于碱性离子浓度。     

东南沿海典型岛屿大气降水化学特征及来源分析

于2020年6月—2021年5月,应用相关分析、富集因子(EF)以及正定矩阵因子分解模型(PMF)和气团来源分析对东南沿海岛屿平潭大气降水化学特征及来源进行了综合评价与分析。结果表明,平潭大气降水pH值为3.96~7.49,平均值为4.78;电导率(EC)为4.9~342.0μs/cm,平均值为24.4μs/cm,高于我国降水背景点值;大气降水中各离子组分当量浓度排序为:Cl->Na+>SO_(4)^(2)>NO-3>Ca 2+>NH+4>Mg 2+>K+>F->NO-2,Cl-和Na+是降水中占比最大的阴、阳离子,其当量浓度占总离子当量浓度的51.4%;NO-3对平潭大气降水酸化的贡献较高(55.9%),且有77%的大气降水酸度被碱性物质中和,其中铵根离子(NH+4)和钙离子(Ca 2+)有着较强的中和能力。富集因子分析结果表明,除海洋源外,地壳源和人为源也是平潭大气降水离子的主要来源;PMF模型结果显示,海洋源、人为源、地壳源和燃烧源分别贡献了平潭大气降水离子的61.1%,23.8%,10.0%和5.1%;气团来源分析结果表明,区域传输对平潭大气降水离子分布及空气质量影响显著,京津冀和长三角地区排放的人为污染物可以经海上传输通道由北至南影响我国下风向地区,给沿海地区大气细颗粒物(PM_(2.5))与臭氧(O_(3))协同控制带来挑战。     

淄博市酸雨状况初步分析

大气污染带来的降水酸化问题是当代全球的重大环境问题之一。早在1900年,许多工业发达的国家已发现酸性降水[PH≤5.6简称酸雨],并对其已有几十年的研究历史。1982年,国务院环境保护办公室组织了全国性的酸雨普查工作,发现我国降水酸度有逐年加重的趋势。长江以南酸雨已较为普遍,其中以重庆和贵阳测得的酸雨PH值最低。前者为3.35,后者为3.44,与世界上严重的瑞典南部和美国东北部相似。     

IC法分析大气颗粒物水溶性离子的国内外研究进展

结合近十多年来国内外在大气颗粒物水溶性离子分析应用方面的研究状况,分别对大气颗粒物中水溶性离子基本特征、分布状况;离子色谱法对大气颗粒物水溶性阴、阳离子的分析方法;大气颗粒物水溶性离子与主要大气污染物和降水化学组成之间的关系;大气颗粒物中水溶性离子与大气降水化学组成之间的关系;大气降尘和沙尘暴尘(沙尘气溶胶)中的水溶性离子等有关的研究内容作了综述和展望.     

淮南市降水化学组成特征与来源分析

2013—2014年,逐次采集淮南城市大气降水样品,对其离子化学组分进行分析测试,并利用酸度分析、中和因子和富集系数等方法对其酸碱物质平衡和离子来源进行了分析。化学组分分析结果表明,淮南城市降水pH为6.23~7.03,雨量加权平均值为6.68,整体上降水没有呈现酸化,大部分酸性物质能被碱性物质中和。主要阴离子为SO_4~(2-)、NO_3~-,雨量加权平均值分别为147.02、62.16μeq/L,两者分别占阴离子总浓度的60.3%、25.3%;主要阳离子为Ca~(2+)、NH_4~+,雨量加权平均值分别为126.42、96.43μeq/L,分别占阳离子总浓度的44.9%、34.3%。利用富集系数法计算结果表明,SO_4~(2-)、NO_3~-主要来源于人为活动排放,Cl~-主要为海洋输入,而Ca~(2+)、Mg~(2+)、K~+则主要来自陆源输入和人为活动。     

Aerosol Scavenging: Model Application and Sensitivity Analysis in the Indian Context

Sulfate aerosols have been found to bethe major contributors to precipitation acidity. Thus,in view of the long-term ecological repercussions theyhave on aquatic ecosystems and their acidity-potential,the present analysis focuses on a case study applicationof the layer-averaged aerosol-scavenging model (Okita et al., 1996) for predicting values of the wet scavengingcoefficient and sulfate concentrations in precipitationsamples on the basis of the information available forsome selected Indian cities. Through sensitivityanalysis (Pandey et al., 1997) the scavengingcoefficient has been found to be very strongly dependenton precipitation intensity. Comparison of modelpredictions has been done with the measured values forDelhi, Mumbai, Calcutta and Chennai in India.     

The occurrence of acid precipitation on the west coast of the United States

Compilation of published and unpublished data shows acid precipitation to be more widespread in the Pacific coastal states than is generally recognized. Although information is scattered and discontinuous, precipitation is definitely acidic in the Los Angeles Basin and north-central california, and in the Puget Sound region in Washington. Acid rain occurrences have been observed in western and eastern Oregon, but data are inadequate for regional generalization. New stations currently being established in Washington and Oregon, largely in resposnse to the recently renewed activity of Mount St. Helens, will greatly facilitate assessment of precipitation acidity in the Northwest.     

Precipitation Chemistry and Occurrence of Acid Rain Over Dhanbad, Coal City of India

The present study investigated the chemical composition of wet atmospheric precipitation over Dhanbad, coal city of India. The precipitation samples were collected on event basis for three years (July 2003 to October 2005) at Central Mining Research Institute. The precipitation samples were analyzed for pH, conductivity, major anions (F, Cl, NO₃, SO₄) and cations (Ca, Mg, Na, K, NH₄). The pH value varied from 4.01 to 6.92 (avg. 5.37) indicating acidic to alkaline nature of rainwater. The pH of the rainwater was found well above the reference pH (5.6), showing alkalinity during the non-monsoon and early phase of monsoon, but during the late phase of monsoon, pH tendency was towards acidity (<5.6~pH) indicating the non-availability of proper neutralizer for acidic ions. The observed acidic events at this site were 91, (n = 162) accounting 56% for the entire monitoring months. The (NO₃ + Cl)/SO₄ ratio in majority of samples was found below 1.0, indicating that the acidity is greatly influenced by SO₄. The calculated ratio of (Ca + NH₄)/(NO₃ + SO₄) ranges between 0.42–5.13 (average 1.14), however in most of the samples, the ratio is greater than unity (>1.0) indicating that Ca and NH₄ play an important role in neutralization of acidic ions in rainwater. Ca and SO₄ dominate the bulk ionic deposition and these two ions along with NH₄ accounts 63% of the annual ionic deposition.     

Extent of acidification in Southwestern Québec lakes

This paper presents the results from the first two areas covered by the statistically-oriented Québec Spatial Lake Acidity Monitoring Network (RESSALQ). It is used in combination with the existing LRTAP-Québec temporal network, the Québec precipitation sampling network (REPQ) and a dose-effect model (SIGMA/SLAM) in order to assess the global extent of damages related to acidity, to detect changes in water quality, and to measure the effects of wet sulphate deposition reduction and those of sulphate target loadings on lake acidity. Results obtained with this network were also used in combination with data issued from the Eastern Lake Survey, in order to establish the relative acidity and sensitivity status of lakes in Eastern North America. While Florida has the highest proportion of very acidic and very sensitive lakes, Québec has a higher overall proportion of sensitive and acidic lakes compared to other areas of the United States.     

Changes in precipitation chemistry in Lithuania for 1981-2004

This paper considers the spatial and temporal variability in concentrations of the potentially acidifying ions in precipitation in Lithuania during the 1981-2004 period. Chemical analysis of precipitation included measurements of pH, conductivity, sulfate (SO4(2-)), nitrate (NO3-), chloride (Cl-), ammonium (NH4+), sodium (Na+), potassium (K+), and calcium (Ca2+). Temporal trends in the potentially acidifying ion concentrations in precipitation and wet deposition were evaluated using the non-parametric Mann-Kendall test and Sen's slope estimator. A statistically significant decline was observed in non-sea salt sulfate (nssSO4(2-)) and hydrogen (H+) ions concentrations (82% and 79%, respectively) and wet depositions (88% and 74%, respectively). Temporal trends both in concentration and wet deposition of nitrate and ammonium were not as pronounced as trends in sulfate concentration. Analysis of air mass backward trajectories was applied to reveal the influence of air mass originating in different regions on wet deposition of acidifying species in Lithuania. Sector analysis clearly showed that wet deposition of sulfur and nitrogen in Lithuania is to a large extent anthropogenic and the main source regions of acidifying species contributing to wet deposition in Lithuania are in South and Central Europe.     

Evaluation of Bulk Deposition in Protected Woodland Area in Western Poland

Research on precipitation carried out systematically at the University station at Jeziory in the Wielkopolski National Park (western Poland) allowed the determination of pollutants deposited with precipitation in this forest ecosystem. During 13 years of study, the pH of precipitation was found to persist at a low level (4.33 on average), which resulted a substantial deposition of H⁺. Values of acidifying and basic ions deposited in this area were determined and compared with the respective figures obtained at selected EMEP stations studying background pollution, the means for Poland, and areas subjected to considerable human impact. The use of the critical load function made it possible to establish that the S and N deposition for 2002–2005 were below its line.     

2005-2011全国酸雨状况分析

根据全国酸雨监测网2005-2011年的监测数据对全国酸雨状况进行分析,得出全国酸雨城市比例、酸雨发生频率及酸雨覆盖面积总体均呈降低趋势,但酸雨形式依然严峻,酸雨类型仍以硫酸型酸雨为主,硝酸盐对降水酸度的贡献逐年增加。与2005年相比,全国硫沉降通量总体呈现下降趋势,硝酸根沉降通量略有增加。中国降水pH年均值与美国、日本及其他东亚酸沉降监测网成员国相当,但主要致酸离子的酸沉降通量处于较高水平。