Hydrochemistry of Rain Water and Atmospheric Pollution in Baghdad,Iraq

The atmospheric pollution in Baghdad was investigated by using rainwater as a media for monitoring of pollution and also compared with the atmosphere pollution at reference stations of Al-Sulaimaniya in north of Iraq and Al-Rutbah in Western Desert of Iraq. Rainwater sampling carried out at period extended from Nov.2007 to April 2008.Thirty five samples of rainwater were collected at seven monitoring

Recent Progress in Atmospheric Chemistry Research in China: Establishing a Theoretical Framework for the “Air Pollution Complex”

Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the“air pollution complex”was first proposed by Professor Xiaoyan TANG in 1997.For papers published in 2021 on air pollution(only papers included in the Web of Science Core Collection database were considered),more than 24000 papers were authored or co-authored by scientists working in China.In this paper,we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years,including studies on(1)sources and emission inventories,(2)atmospheric chemical processes,(3)interactions of air pollution with meteorology,weather and climate,(4)interactions between the biosphere and atmosphere,and(5)data assimilation.The intention was not to provide a complete review of all progress made in the last few years,but rather to serve as a starting point for learning more about atmospheric chemistry research in China.The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established,provided robust scientific support to highly successful air pollution control policies in China,and created great opportunities in education,training,and career development for many graduate students and young scientists.This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances,whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China,to hopefully be addressed over the next few decades.

大气中酰胺的研究进展与展望

综述了近几十年酰胺的相关研究成果,对其基本性质、检测分析手段、浓度水平和分布特征、源和汇、环境和健康效应进行了系统地总结和探讨.外场检测结果表明大气中的酰胺主要分布于城市地区.气态酰胺的来源除自然源的一次排放及二次转化外,还包括污水和废物处理、机动车尾气、工业过程、烹饪等餐饮行业的生物质燃烧、烟草燃烧等人为一次源以及在碳捕获和农业等人为过程中的二次转化.二次转化的化学反应机制主要包括胺的氧化转化以及RO2与NO3自由基的反应等.大气中的酰胺在白天会被OH自由基有效去除,在晚上会被NO3自由基有效去除,在Cl自由基浓度较高的沿海地区或工业排放地区,会被Cl自由基有效去除.与自由基的反应均遵循相似的反应机制,即自由基夺取酰胺分子中的氢原子.此外,酰胺可通过参与新粒子生成(NPF)过程,对二次有机气溶胶(SOA)的生成、大气环境和人体健康产生影响.基于目前对大气中酰胺的研究现状分析,提出了研究展望,未来要加强大气复合污染背景下的检测和分析方法的完善,及对生-消反应机制以及环境健康效应的探讨.

溶剂气氛调控制备TATB

为调控制备不同粒径TATB,提出了一种基于溶剂气氛诱导的试验方法,将纳米TATB暴露在溶剂二甲基亚砜(DMSO)气氛中,利用溶剂气氛诱导控制TATB粒子成长;利用场发射扫描电子显微镜观察了制备的TATB晶体形貌;利用拉曼光谱仪(Raman)和傅里叶变换红外光谱仪测量了TATB的特征峰变化;利用差示扫描量热-热重联用仪(TG-DSC)分析了TATB的热分解性能;研究了溶剂气氛、试验温度以及反应时间对TATB粒径形貌的影响。结果表明,溶剂气氛试验法可诱导纳米TATB生长,调控微观形貌,制备出粒径范围1~17μm的TATB;同时,溶剂气氛试验法制备TATB残余溶剂脱附量较小,仅为4.7mg/g,同溶剂重结晶法制备TATB相比,约为其残余溶剂脱附量的1/21;试验温度和溶剂溶解度是调控纳米TATB晶体生长的两个关键控制条件,通过调控试验温度和溶剂溶解度,可实现TATB粒径的控制生长;拉曼光谱结果显示TATB物相结构未发生变化;热分解结果表明随着TATB平均粒径从3μm增至17μm,其对应的热分解表观活化能E_(a)从208.366kJ/mol增至211.753kJ/mol。

二氧化氮和有机硝酸酯测量技术研究进展

二氧化氮和有机硝酸酯均是大气中非常重要的痕量气体。二氧化氮的浓度是衡量大气污染程度最重要的指标之一,同时,二氧化氮是对流层臭氧的主要来源,也是导致光化学烟雾和酸雨的重要前体物;大气中的有机硝酸酯具有低温稳定、高温易分解的特性,因此是二氧化氮的潜在源,并且对臭氧的全球分布有一定影响。因此,准确获得环境大气二氧化氮和有机硝酸酯浓度对于研究大气化学过程具有重要意义。早在20世纪五、六十年代,化学发光技术和分光光度技术就被用于环境大气二氧化氮的测量,随着技术的发展,差分吸收光谱技术、激光诱导荧光技术、可调谐二极管激光吸收光谱技术、腔衰减相移光谱技术、腔衰荡吸收光谱技术以及腔增强吸收光谱技术等纷纷被用于测量各种环境下的二氧化氮含量。对大气有机硝酸酯的准确测量在氮循环研究方面具有重要的意义。当前,有机硝酸酯的主要测量技术有气相色谱电子捕获检测以及通过热解转化为二氧化氮进行间接测量等方式。综述了国内外对环境中二氧化氮和有机硝酸酯测量技术研究现状和发展趋势,对现有测量方法的原理和优缺点进行了详细介绍和对比,并总结了各个研究方法在外场观测中的应用。

基于同位素技术径流分割研究进展

环境同位素是不受研究者控制的稳定同位素,在同位素径流分割当中需要使用到的同位素^(2)H和^(18)O,同时也会使用到水的其他性质,例如导电性、pH等,氢氧同位素可以有效地表明径流的来源,在进行径流分割之前,需要进行对当地水分的分析,确保同位素的时空均一。总结不同地区的学者在当地测定当地的大气降水线;氢氧同位素和相关的基本概念;二水源径流分割和多水源径流分割的意义、方法等得出以下结论:(1)在进行径流分割之前,需要进行对当地水分的分析,确保同位素的时空均一,否则可能出现某种水源的贡献率达到100%以上;(2)在多水源径流分割的情况下,需要制作三角混合图来确定数据的可靠性;(3)在以后的研究中,可以与GIS等遥感手段结合,这样可以提高径流分割的精度。

Global Two-Dimensional Chemistry Model and Simulation of Atmospheric Chemical Composition

A global two-dimensional zonally averaged chemistry model is developed to study the chemi-cal composition of atmosphere. The region of the model is from 90°S to 90°N and from the ground to the altitude of 20 km with a resolution of 5° x 1 km. The wind field is residual circulation calcu-lated from diabatic rate. 34 species and 104 chemical and photochemical reactions are considered in the model. The sources of CH4, CO and NOx, which are divided into seasonal sources and non-seasonal sources, are parameterized as a function of latitude and time. The chemical composi-tion of atmosphere was simulated with emission level of CH4, CO and NOx in 1990. The results are compared with observations and other model results, showing that the model is successful to simu-late the atmospheric chemical composition and distribution of CH4. Key words Global two-dimensional chemistry model - Atmospheric composition - Emission This work was supported by the State Key Program for basic research “ Climate Dynamics and Cli-mate Prediction Theory” (Pandeng-yu-21).The authors would like to express their thanks to the National Oceanic and Atmospheric Administration (NOAA), Climate Monitoring and Diagnostics Laboratory (CMDL), Carbon Cycle Group for providing the observational data of CO and CH4.

Neoarchean atmospheric chemistry and the preservation of S-MIF in sediments from the São Francisco Craton

Sulfur mass-independent fractionation(S-MIF)preserved in Archean sedimentary pyrite is interpreted to reflect atmospheric chemistry.Small ranges in Δ^(33)S that expanded into larger fractionations leading up to the Great Oxygenation Event(GOE;2.45–2.2 Ga)are disproportionately represented by sequences from the Kaapvaal and Pilbara Cratons.These patterns of S-MIF attenuation and enhancement may differ from the timing and magnitude of minor sulfur isotope fractionations reported from other cratons,thus obscuring local for global sulfur cycling dynamics.By expanding the Δ^(33)S record to include the relatively underrepresented São Francisco Craton in Brazil,we suggest that marine biogeochemistry affected S-MIF preservation prior to the GOE.In an early Neoarchean sequence(2763–2730 Ma)from the Rio das Velhas Greenstone Belt,we propose that low δ^(13)Corg(<-30‰)and dampened Δ^(33)S(-0.4‰to-0.7‰)in banded iron formation reflect the marine diagenetic process of anaerobic methane oxidation.The overlying black shale(TOC up to 7.8%)with higher δ^(13)Corg(-33.4‰to-19.2‰)and expanded Δ^(33)S(2.3‰±0.8‰),recorded oxidative sulfur cycling that resulted in enhance preservation of S-MIF input from atmospheric sources of elemental sulfur.The sequence culminates in a metasandstone,where concomitant changes to more uniform δCorg(-30‰to--25‰),potentially associated with the RuBisCO I enzyme,and near-zero Δ^(33)S(-0.04‰to 0.38‰)is mainly interpreted as evidence for local oxygen production.When placed in the context of other sequences worldwide,the Rio das Velhas helps differentiate the influences of global atmospheric chemistry and local marine diagenesis in Archean biogeochemical processes.Our data suggest that prokaryotic sulfur,iron,and methane cycles might have an underestimated role in pre-GOE sulfur minor isotope records.

THE PROCESSES OF ATMOSPHERIC IMPURITIES TRANSPORTATION OVER THE QINGHAI—TIBET PLATEAU AS REVEALED BY SEASONAL RECORDS OF SNOW CHEMISTRY

Chemical records were recovered from snow pits samples collected over the two transects (south\|north transect and southeast\|northwest transect) of the Qinghai—Tibetan plateau. It shows that the mean concentration of the major ions over the south regions of Mt. Tanggula is lower than that of the north regions. The flux of major ions over north plateau is over 3 times higher than the south. The cloudy atmosphere of the north plateau is mainly contributed to the local input of dust, while in the south plateau, sea salt ions transported by Indian monsoon is considerable. The continental dust transportation from the north and the marine aerosol transportation from the south reach an approximately equilibrium around Mt. Tanggula regions. Stable oxygen isotopic ratios ( δ 18 O) in precipitation from the south\|north transect shows that, over the north plateau, δ 18 O is positively correlated with temperature, while over south of the plateau the correlation becomes weak and δ 18 O is more correlated with the amount of precipitation.

Influence of Vertical Resolution on the Validation of Atmospheric Chemistry Instruments

A large number of validation campaigns for atmospheric chemistry instruments are being carried out and more such studies will be performed in the future. The aims of validation are to confirm the accuracy and precision of the measurement of a new instrument. There are many factors that may deteriorate the validation results and one of them is the vertical resolution of instruments when using the profiles intercomparison ap-proach. The influence from the vertical resolution can be eliminated by using the averaging kernel method but it is necessary to find the conditions for using the method. This study simulated the influence of vertical resolution for a certain curvature. The results show that both the curvature of a profile and the difference of vertical resolution between two instruments have positive correlation with the differences between their measurements. The quantitative estimations of influence for some practical vertical resolutions were ob-tained. The combined error of two instruments was defined as the criteria to judge the significance of influ-ence. A case study based on the simulated results was demonstrated to show when the influence from the vertical resolution should be considered and when such influence can be omitted in order to avoid some un-necessary works in validation.

Simulating the Impacts of Marine Organic Emissions on Global Atmospheric Chemistry and Aerosols Using an Online-Coupled Meteorology and Chemistry Model

To realistically simulate the impacts of marine isoprene and primary organic aerosols (POA) on atmospheric chemistry, a unified model framework with online emissions, comprehensive treatment of gas-phase chemistry, and advanced aerosol microphysics is required. In this work, the global-through-urban WRF/Chem model (GU-WRF/Chem) implemented with the online emissions of marine isoprene and size-resolved marine POA is applied to examine such impacts. The net effect of these emissions was increased surface concentrations of isoprene and organic aerosols and decreased surfaced concentrations of hydroxyl radical and ozone over most marine regions. With the inclusion of these emissions, GU-WRF/Chem better predicted the surface concentrations of isoprene and organic aerosols and the aerosol number size distribution when compared to measurements in clean marine conditions.

国家自然科学基金大气科学学科二级申请代码下设研究方向与关键词解读:D0506大气化学

国家自然科学基金委员会深入推进新时代科学基金改革的背景下,地球科学部大气科学学科率先开展申请代码设置改革,新版申请代码设置方案于2020年投入使用并在实施过程中不断优化。本文主要针对大气学科二级代码D0506大气化学下设研究方向和关键词设置的主要依据进行解读;同时基于文献计量学方法对该代码下不同研究方向的词频、研究热点和趋势进行分析和讨论。新版代码设置方案统筹考虑主要研究方向和研究手段,并根据关键词属性进行分类,便于基金项目申请和评审。基于关键词的文献计量分析明晰了分支学科当前存在的问题及资助导向,有助于进一步促进大气化学及相关方向的发展。

Effect of model errors in ambient air humidity on the aerosol optical depth obtained via aerosol hygroscopicity in eastern China in the Atmospheric Chemistry and Climate Model Intercomparison Project datasets

当前全球气候模式普遍低估中国东部气溶胶光学厚度(AOD)。本文表明,模式低估中国东部地表大气相对湿度是AOD低估的原因之一。研究基于国际大气化学气候模式比较计划的干气溶胶质量浓度结果,用再分析湿度数据替换模拟湿度以计算AOD变化。结果表明,替换后我国大气相对湿度增加,多模式平均的华南年均AOD因此增长45%,华北6-8月AOD增长33%。不同模式采用相似的硫酸盐吸湿增长曲线。相对湿度低估对AOD模拟影响程度主要受吸湿颗粒质量浓度和相对湿度概率分布影响,该结论有助于解释我国AOD模拟误差。

真空紫外光电离质谱及其在大气化学中的应用研究

大气环境污染成因复杂,往往涉及一系列复杂的化学反应过程,且包含众多的挥发性有机物气体分子、自由基和气溶胶颗粒物等,在线检测是大气化学领域的难点和热点问题。真空紫外光电离质谱技术使分子吸收单个光子能量后,在其电离能阈值附近“软”电离,可以获得分子离子质量信息,具有质谱图简洁、碎片离子少和易于解析等特点,能够从分子层面上在线测量大气化学反应过程中关键的化学成分,揭示复杂的大气化学反应机理,在大气化学领域具有较好的应用前景。本文介绍了基于真空紫外激光、同步辐射光源、自由电子激光和真空紫外放电灯等多种光源的真空紫外光电离质谱技术,阐述了近年来该技术在大气挥发性有机物、自由基以及气溶胶颗粒物化学成分检测方面的进展,并展望真空紫外光电离质谱技术的发展方向。

酸沉降对缙云山湖水化学的影响

为了解我国典型酸雨区酸沉降时间变化特征以及对水化学特征的影响,利用2001—2020年东亚酸沉降监测网(EANET)的湿沉降与湖泊监测数据,使用MK检验分析缙云山酸沉降和湖水化学长期变化特征,使用Spearman相关系数明确酸沉降对湖水化学特征的影响。结果表明:2001—2020年,缙云山酸雨问题已得到改善,但降水p H值在3.94—5.15,平均值为4.41,酸雨问题依然严峻。硫和溶解无机氮(dissolved inorganic nitrogen,DIN)沉降通量分别为32.85 kg·hm^(-2)·a^(-1)和22.55 kg·hm^(-2)·a^(-1),酸雨类型已由“硫酸型”转变为“硫酸-硝酸混合型”。湖水pH值的范围在5.25—7.50,平均值为5.86,酸化频率为30%。湖水pH值与降水pH值之间的相关性(r=0.56,P<0.01)表明酸沉降对湖水酸化有一定作用。因此,对于酸化水体的治理须考虑大气沉降因素,只有协同治理大气污染才能根治水生生态系统的退化现象。

基于人工智能与大数据的双碳大气环境信息化应用进展与展望

[目的]二氧化碳与大气污染物化石燃料排放同源,在碳达峰碳中和的双碳进程中应协同治理,改善双碳大气环境。大气环境信息化应用主要基于大气化学传输数值模式展开,而双碳大气环境信息化应用还处于起步阶段。近年来,人工智能与大数据技术在双碳大气环境上的应用愈加广泛,蕴育科研范式从数值模式向与人工智能、大数据深度融合变革,因而亟需梳理当前进展并展望未来发展方向与路径。[方法]通过调研领域工作,勾勒基于人工智能与大数据的双碳大气环境信息化应用的研究路径和发展方向。[结果]双碳大气环境信息化应用应以人工智能、大数据科技创新实现对大气化学传输模式的融合替代,形成应用体系,实现更高精度、更快速度的数字化治理。[局限]本文提出的概念与设计,有待于未来的实施与验证。[结论]人工智能与大数据技术的应用,带来双碳大气环境科研范式变革机遇,同时也提出了挑战。协同推进算法突破与信息化系统研制,有助于实现这一科研范式变革。

大气化学实验教材建设的探索与实践

大气化学实验课程建设需求非常急迫,但配套实验教材却较为缺乏。该文介绍了《大气化学实验》教材的思路、特色和编写实践。该教材凸显了大气科学学科特点,既包含参照国标方法的基础性业务部门标准实验,又突出引入大型仪器设备的热点前沿实验技术方法,内容基本覆盖大气化学理论知识点,鼓励自主设计实验,旨在帮助培养大气科学实用型和创新型本科人才。该教材的建设,有望解决大气化学实验教材不足的问题,为本课程及相关课程建设提供参考和借鉴。

大气中氯氟烃类物质浓度变化的研究

通过低温脱水和低温浓缩（－１９６℃），建立了用气相色谱（ＥＣＤ检测器）测定大气中超痕量氯氟烃类物质（ＣＥＣｓ）的分析方法．对上海市清洁大气中ＣＦＣｓ本底浓度进行了监测，并与日本东京大学的数据进行了比较．结果表明，１９９７年以来，上海市郊大气中ＣＦＣ－１１和ＣＦＣ－１２浓度均呈下降趋势．上海ＣＦＣｓ排放量与发达国家相比仍处于较低的水平．

中国对流层二氧化硫光化学氧化过程的数值研究

利用一个三维非静力区域大气化学输送模式与中尺度气象模式MM5相连接构成一个数值模拟系统 ,模拟了中国地区对流层臭氧与其前体物的分布以及二氧化硫转化为硫酸盐的过程 ,模式包括地面源排放、大气输送和扩散、干沉积、气相化学反应和云雨过程 .结果表明 :日间 ,O3 浓度主要由NOx 和NMHC的源排放和光化学反应过程支配 ,大气辐射是光化学反应强弱的决定因子 ,其强度可使SO2 、O3 和SO4 2 -的生成浓度呈现不同的日变化和季节变化 ,结果表明高浓度的O3 对二氧化硫转化为硫酸盐的化学过程有很大的促进作用 ,然而 ,这种作用受NMHC浓度的影响很大 ,较高浓度的NMHC使O3 浓度上升 ,但同时增加了对OH等自由基的消耗 ,使SO2 的转化率降低 .

北京市大气OH自由基测量结果及其特征

利用 2种基于高效液相色谱技术的大气OH测量方法测定了北京城市大气中OH自由基 ,得到了其浓度水平和日变化情况 .测得夏季日间最大OH浓度为～ 8× 1 0 7cm- 3,秋季日间最大浓度为 2× 1 0 7～ 4× 1 0 7cm- 3,并根据同步测量光强和其它污染物的浓度 ,分析了OH浓度与这些条件的相关性 .结果表明 ,OH浓度与UV B相对强度、O3和HNO2 的浓度具有一定的正相关性 ,而与NOx 浓度具有反相关性 .