近25 a杭州市酸雨变化特征分析

根据1993—2017年杭州市酸雨及环境气象观测资料统计分析表明,2007年以前杭州降水p H值主要表现为强酸雨或特强酸雨,2007年以后则以弱酸雨或较弱酸雨为主;降水K值在经历2004—2007年的高值后,近几年又下降到90年代水平。酸雨频率呈持续下降趋势,特别是特强酸雨频率在2007年之后维持在低位;冬季和春季是酸雨高发的季节,而夏季相对较低。从近5 a杭州各区、县(市)酸雨频率及p H值来看,各地年均p H基本呈上升趋势;各地(除临安外)酸雨频率均逐年下降。此外,通过降水过程中的p H值分析表明在大雨或暴雨时较容易发生酸雨,连阴雨过程容易出现p H低值;环境空气中SO2、NO2浓度与p H值变化呈负相关,与电导率K值呈正相关。     

杭州市酸雨特征分析

利用杭州市气象局1992-2008年的酸雨监测资料,包括年平均降水、pH值、酸雨频率、风速风向等,分析杭州市酸雨形成的因子,并对酸雨形成的原因进行探讨。结果表明:杭州市酸雨17年间pH平均值为4.40,酸雨污染问题比较严重。从年变化趋势来看,酸雨强度较大,受酸性降水污染较重,但近几年来有逐年减缓的趋势;从季节变化趋势来看,酸雨春季和冬季较为严重,酸雨频率也比较大,而夏季和秋季降雨酸度和酸雨频率均比较小。杭州市酸雨形成的主要原因是大气中SO2、NOX等污染物浓度超标,同时与降水量、风向、风速、大气层结等气象条件密切相关,并根据其原因提出控制酸雨的措施和策略。     

汉台区2006—2009年酸雨特征及对策建议

利用汉中基准气候站2006—2009年酸雨pH值和气象资料,统计分析了汉台区酸雨时间分布和强度特征以及酸雨与气象要素的关系,结果表明:汉台区秋季、冬季和初春酸雨频率较大,春末和夏季酸雨频率较小;2006—2009年酸雨频率分别为16%、16%、20%、22%,有逐步增大的趋势;汉台区出现的酸雨酸性强度总体较弱;汉台区酸雨主要集中在日降水量为0～20mm时,暴雨以上级别降水时几乎未出现酸雨;酸雨对应的东北风(NE)、偏东风(ENE)、南风(S)和偏南风(SSE)最多,占总次数的60%。应对酸雨危害的对策建议主要有:通过加强对燃煤和机动车尾气的治理,从源头防治酸雨;倡导环保和绿色理念。     

上海地区雨水酸度与天气背景的关系

1981—1983年在上海地区11个观测站进行了雨水pH值观测,取到资料2448份.从资料分析得到:(1)雨水pH值与天气背景有关,静止锋天气影响时,酸雨出现几率达44.5％,雨水较酸;暖锋天气时,酸雨出现几率仅9％.(2)台风、高压边缘天气影响下,酸雨的形成主要是受局地污染源的影响;但静止锋、冷锋、低压系统天气时,酸雨的形成不仅受局地污染源的影响,而且还可能受随气流输送来的外来污染物的影响.     

降水酸度与降水物理量关系的分析

本文利用1983—1985年长春等地的酸雨监测资料，分析了降水酸度与降水量、降水强度，降水类型、降水的季节变化以及雨滴大小分布之间的关系，还初步分析了降水对大气污染物的冲洗作用。     

一次碱性降水过程的个例分析

本文根据1983年4月28日至29日一次降水过程所监测的降水酸度资料,分析讨论了大气中颗粒物对降水酸度的影响,及碱性降水过程发生的天气条件。一、杭州市酸性降水概况杭州是长江以南地区经常发生酸雨的城市之一。从已测定的降水酸度结果表明:杭州一年四季任何时期都可以发生酸性降水,大部分酸性降水的pH值在4.1—5.1之间。pH     

近5a江苏省苏南五市酸雨分布特征分析

统计江苏省苏南地区南京、镇江、常州、无锡和苏州5市7个酸雨监测站2007年1月至2011年12月的酸雨监测资料得到:(1)酸雨发生频率以东山最高,南京最低;2011年最低,2009年最高。强酸雨发生概率以东山最高,溧阳最低;3站同时出现强酸雨的概率最高,7站同时为强酸雨的仅2009年2月22日1 d。(2)四季均为酸性降水;酸雨强度以东山最强,溧阳最弱。2011年呈弱酸性,其余3 a呈强酸性。     

我国降水酸度的初步研究

1981年3月至1983年4月,我们在全国不同地区选定了四十几个测点对降水酸度进行了观测。 观测资料表明,酸雨出现的频率,南方城市较北方为高,酸度也较强,酸雨出现频率最高值达到90％。说明酸雨在某些地区已相当严重。pH的最低值是庐山的含鄱口(测值达3.10)。我国北部地区降水多为中性,但局部地区也有酸雨出现。沿海城市青岛也出现酸雨。 作者结合地理环境、污染物的迁移输送以及天气系统等,对降水酸度变化进行了初步分析。     

杭州市逆温与大气污染的关系

本文根据杭州市(1986—1988年)三年的探空资料以及同期的常规和短期(3482个数据)SO_2监测资料,统计分析杭州市逆温分布规律,研究逆温与SO_2污染浓度的关系,得到一些初步规律,为污染物的控制和排放提供科学依据。     

江西省酸雨变化特征及其与气象条件的关系

利用江西省气象部门12个酸雨监测站2007—2011年的观测资料,分析了江西省酸雨的时空分布特征。结果表明,近年来江西省酸雨污染总体上有缓和趋势。夏半年酸雨污染较轻,其中8月的污染最轻;冬半年酸雨污染较重,其中1月的污染最为严重。整个江西省都受到酸雨污染的威胁,但污染程度分布不均,江西中西部的吉安、宜春以及东北部的景德镇污染较为严重,江西中东部的鹰潭、上饶以及西部的萍乡污染较轻。通过对酸雨与气象条件的关系分析发现,江西省降雨的pH值随降雨量的增加先减小再增大,小雨、中雨和大雨的pH值较小,而暴雨和大暴雨的pH值较大。850 hPa层为北风(N)、东北偏北风(NNE)、东北风(NE)或东北偏东风(ENE)(总方向角为348.75°—78.75°)时,南昌降雨pH值较高,东南偏东风(ESE)时南昌降雨的pH值较低;850 hPa层为东风时赣州降雨的pH值较高,北风(N)时赣州降雨的pH值较低。     

伊犁地区酸雨状况分析

利用伊宁国家基准气候站13a的酸雨资料,对伊犁地区酸雨状况进行了统计分析,参考其它的气象资料和环境资料对于伊犁的酸雨状况所代表的空气质量现状进行了分析论证。结果表明伊犁地区酸雨有很明显的季节特点,冬季最为严重,其中供热燃煤是最重要的原因。     

近11 a南京市酸雨变化及其成因分析

本文结合2003—2013年以来南京国家基准气候站的逐日酸雨资料以及地面气象资料和高空探测资料,分析了近11 a来南京地区的酸雨变化特征以及相应的气象和气溶胶影响因子变化。所得结果表明:近11 a来南京地区的酸雨变化总体呈明显恶化态势,表现为酸雨的发生率明显提高,相应的酸度(pH值)显著下降;从影响酸雨变化的气象条件看,酸雨的pH值随着降水量增大而降低;垂直不稳定条件是影响酸雨的另一重要方面,酸雨事件出现时通常伴随出现高空逆温,在冬季有99%的事件出现逆温;分析850 hPa的风速和风向情况发现,冬、夏季分别有47%和52%的酸雨事件出现东风或东北风,这可能说明外部的输入性污染物对酸雨的形成也起着重要的作用。     

大同市酸雨变化特征及其与气象要素的关系

利用2007—2009年大同市酸雨资料,应用《酸雨观测规范》方法对大同市酸雨变化及其与气象要素的关系进行分析。结果表明：大同市酸雨发生频率为25.0%—36.36%,10月酸雨频率最高,达到75%;其他月份酸雨频率较低。大同市夏季酸雨强度为弱酸雨程度,而秋季酸雨频率则为最高。大同市小雨时酸雨发生频率为33.33%;中雨时酸雨发生频率为19.23%;大雨时酸雨发生频率为60.00%;暴雨时酸雨发生频率为0。由此可见,大同市在大雨天气时,酸雨出现的概率较高。随着风速的增大,降水的酸雨频率逐渐增大。大同市在S风向下的酸雨频率最高为18.60%,ESE和NNW风向下的酸雨频率较高为13.95%。通过分析大同市酸雨变化规律、气象气候条件等因素对酸雨的影响,探讨影响大同市酸雨形成的主要因素,从而为大同市酸雨污染控制提供科学依据。     

石家庄市酸雨污染现状研究

利用1992—2005年石家庄气象站酸雨观测资料,计算了近14 a的年平均降水pH值、酸雨发生频率等反映酸雨强度的参数,分析了酸雨的变化特征以及pH平均值与气象条件、电导率、空气污染的关系。结果表明：1992—2005年石家庄年平均酸雨发生频率为8.7%;酸雨主要发生在夏、秋季,占全年的74.4%;月平均降水pH值与电导率具有相似的变化规律,显著相关系数为0.661;SO2浓度的逐年下降是石家庄市酸雨减弱的主要原因;月平均风速和月平均降水pH值相关不显著;不同降水等级酸雨的发生频率差异较大,暴雨的酸雨发生频率最高为41.67%;采用Daniel趋势检验法分析表明,石家庄酸雨污染呈下降趋势。     

Atmospheric variability and binary homogeneous nucleation: A parametrisation and conditions required for a significant effect

The binary water–sulphuric acid nucleation has long been considered an important path for new particle formation in the atmosphere. The formation rate depends nonlinearly on temperature and vapour concentrations. We aim to find out if atmospheric small scale and mesoscale spatial and temporal variability can increase the nucleation rate significantly. Simultaneous and separate effects of variation in temperature, humidity and sulphuric acid concentration on the mean nucleation rate have been modelled. We have assumed that the distributions of variables are Gaussian and compare the mean of simulated nucleation rates with the nucleation rate in mean conditions without variation. According to our studies the atmospheric variability can increase the mean nucleation rate by orders of magnitude but the significant effect is limited to specific conditions. The effect seems to be more important in the lower troposphere than in the upper troposphere, where temperature and sulphuric acid concentrations are lower. In addition, our model simulations indicate that the atmospheric variability can only explain part of the difference between measured and theoretically required sulphuric acid concentrations in conditions where particle formation has been observed. We have parametrised the effect of atmospheric variability as a simple correction factor for the effect of temperature and humidity variation.     

Atmospheric variability and binary homogeneous nucleation: A parametrisation and conditions required for a significant effect

The binary water–sulphuric acid nucleation has long been considered an important path for new particle formation in the atmosphere. The formation rate depends nonlinearly on temperature and vapour concentrations. We aim to find out if atmospheric small scale and mesoscale spatial and temporal variability can increase the nucleation rate significantly. Simultaneous and separate effects of variation in temperature, humidity and sulphuric acid concentration on the mean nucleation rate have been modelled. We have assumed that the distributions of variables are Gaussian and compare the mean of simulated nucleation rates with the nucleation rate in mean conditions without variation. According to our studies the atmospheric variability can increase the mean nucleation rate by orders of magnitude but the significant effect is limited to specific conditions. The effect seems to be more important in the lower troposphere than in the upper troposphere, where temperature and sulphuric acid concentrations are lower. In addition, our model simulations indicate that the atmospheric variability can only explain part of the difference between measured and theoretically required sulphuric acid concentrations in conditions where particle formation has been observed. We have parametrised the effect of atmospheric variability as a simple correction factor for the effect of temperature and humidity variation.     

Modelling the formation of H2SO4–H2O particles in rural, urban and marine conditions

The factors which affect the formation of new sulphuric acid particles in different atmospheric conditions are investigated. An atmospheric chemistry gas phase box model coupled to a three mode integral aerosol dynamics model is used. The simulations show the dependence of the concentration of nucleation mode particles on initial pre-existing particles, the intensity of UV radiation, the emissions of dimethylsulphide (DMS) and the ratio of emissions of hydrocarbons (HC) and NO_x present in the atmosphere. Eight different basic cases are simulated in urban, rural and marine conditions. The effects of pre-existing particles as a sink of sulphuric acid are clearly seen. The increased UV radiation is also seen to enhance particle formation via sulphuric acid route significantly.     

Exchange of Short-Chain Oxygenated Volatile Organic Compounds (VOCs) between Plants and the Atmosphere: A Compilation of Field and Laboratory Studies

Field and laboratory investigations of the exchange of the short-chain organic acids – formic acid and acetic acid – as well as their homologous aldehydes are discussed. Both acids are substantially released from several plant species. Emission measurements under field conditions are compiled to give an overview of three years of measurements. Emission rates from several tree species were found in the range between zero and 60 nmoles m^–2 min^–1 for acetic acid and between zero and 90 nmoles m^–2 min^–1 for formic acid though also a deposition has been observed to orange trees. Investigations under laboratory conditions showed an order of magnitude lower emission rates with significant differences under light and dark conditions, and a deposition was observed under certain conditions. Hence, low emission rates or even a bi-directional exchange, emission as well as deposition have to be taken into account. Further differences between field and laboratory studies are discussed considering age of trees, stress effects and a potential production of acids by photochemical conversion of precursors inside enclosures during sampling. Field data on the exchange of form- and acetaldehyde show a complex behavior. We found emission as well as uptake. The bi-directional exchange is significantly triggered by the ambient mixing ratios of both aldehyde species and exhibits a compensation point. Further studies are needed for generalization of the exchange of these and potentially also for other compounds.     

郑州市降水pH值变化分析

利用郑州市国家基准气候站1994~2005年酸雨观测资料,分析研究了郑州市降水pH值的状况和变化,结果表明:郑州市近几年降水的pH值有逐年减小的趋势,pH值小于5.6的降水次数和频率有增加的趋势;从季节分布来看,降水pH值秋冬比春夏小。酸雨增强的主要原因是煤炭的高消耗排放的SO2量较大,再者是机动车废气排放增加,另外气候条件对酸雨的形成也有影响。     

湖北西部城市酸雨特征及其与气象条件的关系

根据对湖北省西部宜昌、襄樊、巴东、十堰等城市自然降水pH值的检测结果,对降水pH值变化、时空分布,降水的化学成分、酸雨出现时的风与气象条件、酸雨与降水云类的关系进行了详细的分析。分析结果表明:酸雨形成与当地的地理条件和气象因子有关。稳定的大气环境对酸雨形成有利,较强的逆温和静风频率,可以为当地降水的二次酸化提供有利条件。各地酸性降水化学成分中阴阳离子SO42-/NO2-比值表明,西部城市酸雨具有典型的硫酸型特征。巴东监测的时间较短,但酸雨年出现频率有上升的趋势,并且酸雾出现的几率比较大。襄樊、十堰酸雨出现频率较低与雨水中有较高浓度的阳离子有关。