深圳秋季大气有机气溶胶来源与挥发性研究

使用热扩散管与长飞行时间气溶胶质谱联用系统对2020年深圳市秋季亚微米级气溶胶进行在线测量,获取和分析了气溶胶的化学组成及挥发性特征,并利用正矩阵因子分析法（PMF）对有机气溶胶进行了来源解析.结果显示：观测期间,气溶胶平均质量浓度为（28.3±11.1）μg/m³（9.5~76.8μg/m³）,其中,有机物占比最高,为57.9%,其次为硫酸盐（24.7%）.PMF对有机气溶胶解析结果得到四类源,分别为烃类有机气溶胶（HOA）、餐饮源有关的有机气溶胶（COA）、低氧化性的氧化有机气溶胶（LO-OOA）和高氧化性的氧化有机气溶胶（MO-OOA）.HOA、COA、LO-OOA和MO-OOA平均分别占到总有机物的9.1%、27.2%、31.8%和31.9%.进一步采用NO⁺/NO₂⁺比值法和PMF方法估算有机硝酸酯（ON）浓度,两种方法估算结果相关性良好,ON的平均浓度为0.17~0.25μg/m³,占总有机气溶胶质量的1.5%~9.7%,说明其对深圳大气气溶胶贡献显著.ON与各有机气溶胶因子的相关性比对发现,其与LO-OOA相关性最高（R=0.80）,说明其可能来源于新鲜的二次生成反应.挥发性研究结果得出,深圳市气溶胶主要化学组分挥发性顺序为氯盐≈无机硝酸盐 > 铵盐 > 有机物 > 有机硝酸酯 > 硫酸盐,对于有机气溶胶因子,其挥发性排序为LO-OOA > HOA > COA > MO-OOA,除了LO-OOA,其余因子挥发性与其氧化态排序一致,而LO-OOA从50~70℃组分下降最多,说明其所含组分挥发性差异最为明显.     

深圳大气有机硝酸酯粒径分布特征和来源研究

于2021年3月30日至2021年4月17日利用超高分辨率气溶胶飞行时间质谱(Long-ToF-AMS),对深圳城市大气中的颗粒态有机硝酸酯(pON)开展高精度分析.基于两种估算pON的方法,计算得出pON对有机气溶胶(OA)的贡献占比为5.08％～11.00％.pON的日变化特征显示,其高值主要出现在夜间时段(19:...     

纳米二氧化钛光催化技术与大气污染治理

简要介绍了纳米二氧化钛（TiO₂）光催化技术的发展历史和反应原理.重点讨论了纳米TiO₂光催化技术在大气污染物催化转化方面的研究进展与前沿问题,分析发现该技术对一些典型大气有机污染物、氮氧化物、硫化物以及二氧化碳等有较高的去除效率（去除率多在80%~99%之间）.总结了纳米TiO₂光催化技术在大气污染治理中的应用状况,结果表明在空气净化、机动车尾气净化、化石燃料脱硫以及温室效应控制等方面已初步进入实用阶段.     

海洋浮游植物胞外多聚物的研究进展

海洋中胞外多聚物（extracellular polymeric substances,EPS）是一类富含碳的黏性物质,由酸性多糖组成,主要由浮游植物产生。EPS主要分为三类:细胞涂层EPS、溶解性EPS和透明胞外聚合颗粒物（transparent exopolymer particles,TEP）。EPS本身呈溶解态,属于溶解有机碳库;但EPS可通过凝结或起泡方式转换形成颗粒态的TEP,属于颗粒有机碳库。EPS能被微生物降解或吸收,直接参与微食物环的碳循环。颗粒态的TEP可聚集生物有机颗粒形成"海洋雪",加快有机碳的沉降。因此EPS成为连接溶解态和颗粒态有机碳的桥梁,有效改变了海洋生态系统中有机碳库的分配,在塑造海洋生态系统结构和功能中具有重要地位。本文从EPS的特点、形成机制、对细胞积聚和海洋碳循环的影响等方面综述了目前EPS的研究进展。     

大气汞监测技术进展

为了切实履行《关于汞的水俣公约》,落实美丽中国建设战略,我国亟待加强对大气环境及各涉汞行业的监管.采用文献调研、分类梳理的方法,系统地分析和总结了近年来国内外常用的大气汞监测技术现状与问题,并探讨了未来技术发展方向.结果表明:为了满足大气环境中低浓度多形态汞的监测需求,越来越多功能的大气汞监测技术被研发,当前基于AFS（原子荧光光谱）和AAS（原子吸收光谱）等方法的监测技术对Hg0（元素汞）可实现ng/m3的检出限,对Hg2+（氧化态汞）和Hgp（颗粒态汞）有着低至pg/m3的检出限.自动化采样监测技术是未来汞监测的发展趋势,当前技术对大气中Hg0有着2.5~5.0 min水平的时间分辨率,对大气中Hgp可达到1~2 h的时间分辨率,同时可实现远程传输数据.人工采样监测和被动采样监测技术虽然时间分辨率较差,但在Hg2+和Hgp的监测方面有着一定优势.研究显示,完善大气汞监测管理体系,除了需要研发更强大的Hg2+和Hgp测定技术用于理解相关迁移转化过程,还亟待在相应的标定方法上实现技术革新,并应用这些技术组建地区和全球大气汞监测网络.      

大气中有机硫酸酯研究进展

介绍了国内外大气环境中有机硫酸酯（OSs）的研究现状,分别简述了OSs的理化特征及影响因素、不同分析方法及对应特征、OSs的分类、来源及形成机制、OSs在大气中的转化及归趋等内容,并对目前常见的OSs分子式和结构式以及三种典型的形成机制进行了归纳总结.聚焦目前OSs研究的前沿领域,探讨了目前OSs研究中有待解决的热点问题,并对未来的研究工作提出建议与展望.     

夏季东海生源硫的分布、通量及其对非海盐硫酸盐的贡献

对2012年6月东海表层海水中二甲基硫（DMS）、二甲巯基丙酸内盐（DMSP）和二甲亚砜（DMSO）的浓度分布特征及其影响因素进行了研究,并估算了DMS的海-气通量及其对大气气溶胶中非海盐硫酸盐（nss-SO₄^2-）的贡献率.结果表明,DMS、溶解态DMSP（DMSPd）、颗粒态DMSP（DMSPp）、溶解态DMSO（DMSOd）和颗粒态DMSO（DMSOp）的浓度平均值±标准偏差为（5.71±5.23）,（5.94±3.68）,（23.84±14.15）,（9.14±10.52）和（11.01±5.81）nmol/L.DMS、DMSP和DMSOp浓度均在28oN~29oN,122°E~123.5°E海域呈现高值中心,沿中心向外扩散降低,并且与叶绿素a（Chl-a）的分布趋势基本一致.除DMSOd外,3种二甲基硫化物与Chl-a表现出显著的相关性,表明浮游植物生物量是影响东海生源有机硫化物生产分布的关键因素.此外,夏季东海DMS海-气通量介于（0.93~101.02）μmol/（m²·d）,平均值±标准偏差为（18.13±21.42）μmol/（m²·d）.夏季东海生源硫释放对nss-SO₄^2-的贡献率仅为2.2%,表明人为排放是东海大气气溶胶中nss-SO₄^2-的主要来源.     

关于硝酸酯可生物降解性的研究进展

本文就甘油三硝酸酯（ＧＴＮ）、缩水甘油硝酸酯、乙二醇二硝酸酯（ＥＧＤＮ）、二硝酸异山梨糖醇酐（ＩＳＤＮ）、季戊四醇硝酸酯（ＰＥＴＮ）、硝酸纤维等六种硝酸酯的可生物降解性及其相应的作用机理的研究进展情况作了概述，并提出了目前在研究工作中需进一步解决的一些问题。     

大气环境中PAN污染现状及转化机理的研究进展

过氧乙酰硝酸酯（PAN）是光化学烟雾中重要的二次有机污染物，跟细颗粒物和臭氧污染都有着相关联系，已逐渐引起国内外学者的广泛关注。基于近年来国内外对PAN进行的相关研究，总结了PAN的污染现状、监测技术和生成降解机制等方面的研究进展。目前监测到的PAN浓度的空间区域特征总体呈现出城区明显大于郊区，日浓度高峰值通常出现在12:00-16:00之间，一年中夏季平均浓度较低。PAN生成速率主要受过氧乙酰（PA）自由基的生成速率影响，大气中PA自由基主要由乙醛、丙酮、甲基乙二醛、丁烯酮和联乙酰等含氧挥发性有机物生成，多数情况下乙醛对PA自由基的贡献率最高。PAN热解反应路径O-N键断裂优于O-O键断裂以及协同的C-C键和O-O键断裂；水解反应路径C-O键断裂和无水分子参与的O-N键断裂优于水分子参与的O-N键断裂。     

鹤山气溶胶光学性质和单颗粒化学组分的研究

2014年10~11月在广东省鹤山大气超级站利用单颗粒气溶胶质谱仪（SPAMS）、积分式浊度仪和黑碳仪在线观测了单颗粒气溶胶的化学组成与气溶胶光学特征.采用Art-2a分类法将单颗粒分为9类：有机碳-硫酸盐/硝酸盐颗粒（OC-Sulfate/Nitrate）、元素碳-硫酸盐/硝酸盐颗粒（EC-Sulfate/Nitrate）、元素碳有机碳-硫酸盐/硝酸盐颗粒（ECOC-Sulfate/Nitrate）、高分子有机碳颗粒（HOC）、海盐颗粒（Sea-salt）、硅酸盐颗粒（Si-rich）、左旋葡聚糖颗粒（Lev）、钾-硫酸盐/硝酸盐颗粒（K-Sulfate/Nitrate）、金属颗粒（Metal）.从清洁期到灰霾期气溶胶的吸收系数、散射系数和单次散射反照率（SSA）显著升高,气溶胶消光能力增强,同时EC-Sulfate/Nitrate颗粒占比从34.8%降至31%,OC-Sulfate/Nitrate颗粒从9.9%增加至23.6%,K-Sulfate/Nitrate二次颗粒从8.5%增加至14%,且灰霾期OC-Sulfate/Nitrate颗粒与硫酸盐、硝酸盐和铵盐的混合程度增强,因此老化的OC-Sulfate/Nitrate颗粒和二次组分颗粒对气溶胶消光系数的增加有重要贡献.在大气相对湿度从50%增加到70%以上的过程中,气溶胶散射系数和吸收系数升高,消光系数由326.1Mm^-1增加到362.9Mm^-1,SSA有所下降,PM_2.5质量消光效率由4.98增加到5.99,EC-Sulfate/Nitrate颗粒和K-Sulfate/Nitrate二次颗粒占比下降,而OC-Sulfate/Nitrate颗粒的占比由7.79%增加到14.29%,且OC-Sulfate/Nitrate颗粒中富含硫酸盐、硝酸盐和铵盐,表明高相对湿度下老化的OC-Sulfate/Nitrate颗粒数目增多对气溶胶消光系数的增强有重要影响.     

Review of the influencing factors of secondary organic aerosol formation and aging mechanism based on photochemical smog chamber simulation methods

The formation and aging mechanism of secondary organic aerosol (SOA) and its influencing factors have attracted increasing attention in recent years because of their effects on climate change, atmospheric quality and human health. However, there are still large errors between air quality model simulation results and field observations. The currently undetected components during the formation and aging of SOA due to the limitation of current monitoring techniques and the interactions among multiple SOA formation influencing factors might be the main reasons for the differences. In this paper, we present a detailed review of the complex dynamic physical and chemical processes and the corresponding influencing factors involved in SOA formation and aging. And all these results were mainly based the studies of photochemical smog chamber simulation. Although the properties of precursor volatile organic compounds (VOCs), oxidants (such as OH radicals), and atmospheric environmental factors (such as NO_x, SO₂, NH₃, light intensity, temperature, humidity and seed aerosols) jointly influence the products and yield of SOA, the nucleation and vapor pressure of these products were found to be the most fundamental aspects when interpreting the dynamics of the SOA formation and aging process. The development of techniques for measuring intermediate species in SOA generation processes and the study of SOA generation and aging mechanism in complex systems should be important topics of future SOA research.     

Organic chloramines in chlorine-based disinfected watersystems: A critical review

This paper is a critical review of current knowledge of organic chloramines in water systems,including their formation, stability, toxicity, analyticalmethods for detection, and their impact on drinking water treatment and quality. The term organic chloramines may refer to any halogenated organic compounds measured as part of combined chlorine (the difference between themeasured free and total chlorine concentrations), andmay include N-chloramines, N-chloramino acids, N-chloraldimines and N-chloramides. Organic chloramines can form when dissolved organic nitrogen or dissolved organic carbon react with either free chlorine or inorganic chloramines. They are potentially harmful to humans and may exist as an intermediate for other disinfection by-products. However, little information is available on the formation or occurrence of organic chloramines in water due to a number of challenges. One of the biggest challenges for the identification and quantification of organic chloramines in water systems is the lack of appropriate analytical methods. In addition, many of the organic chloramines that formduring disinfection are unstable,which results in difficulties in sampling and detection. To date research has focussed on the study of organic monochloramines. However, given that breakpoint chlorination is commonly undertaken in water treatment systems, the formation of organic dichloramines should also be considered. Organic chloramines can be formed frommany different precursors and pathways. Therefore, studying the occurrence of their precursors in water systems would enable better prediction and management of their formation.     

固定源废气VOCs排放在线监测技术现状与需求研究

结合我国"十二五"大气挥发性有机物(VOCs)污染防治要求和当前国内外相关监测管理现状,研究分析了适合我国固定污染源废气VOCs排放在线监测的仪器系统结构和技术特点,进而从系统采样预处理技术和分析测量技术两方面,提出了符合我国固定污染源废气VOCs排放在线监测技术特点的发展需求.     

The levels, sources and reactivity of volatile organic compounds in a typical urban area of Northeast China

Air concentrations of volatile organic compounds (VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and 9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most (36.15%) to the total propene-equivalent concentration of the measured VOCs, followed by combustion emission (16.92%), vegetation emission and secondary formation (14.33%), solvent usage (10.59%), petrochemical industry emission (9.89%), petrol evaporation (6.28%), and liquefied petroleum gas (LPG) usage (5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O₃ formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics, e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O₃ pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O₃ pollution in Shenyang.     

DBD降解氮中甲苯气体产生的二次有机副产物检测

为了研究低温等离子体降解有机废气过程中产生的二次有机副产物的形成机理及其影响因素,以介质阻挡放电(DBD)产生的低温等离子体降解氮中甲苯气体为研究对象,利用质子转移反应飞行时间质谱仪(PTR-TOF-MS)实时在线检测降解尾气中有机副产物的成分及其浓度,分析了二次有机副产物形成的机理,探讨了影响二次有机副产物生成的关键因素.研究发现,氮中甲苯低温等离子体降解尾气中主要的有机副产物为HCN和CH3CN,其浓度与待降解甲苯的平均可资用能有关.由平均可资用能的测试分析可知,在DBD有机物降解装置、电源输入功率、降解气体流量等参数确定的情况下,待降解有机物存在一个浓度极值,大于该浓度极值将使得降解尾气中有机副产物的浓度明显增加.在低温等离子体降解装置参数确定的情况下,控制待降解有机物的浓度是减少有副产物产生的有效手段和方法.     

复合污染条件下人为源VOCs的SOA生成研究进展

大气细颗粒物(PM_2.5)仍是我国空气质量持续改善的重大挑战.近年来,二次有机气溶胶(SOA)对PM_2.5的贡献日益凸显.因此,深入认识复合污染条件下SOA生成机制和影响因素可以为进一步降低PM_2.5提供重要理论依据.实验室模拟是深入认识SOA生成机制的关键途径,也是模式模拟参数化方案的可靠来源之一.主要综述了我国多污染物共存条件下典型人为源挥发性有机物(VOCs)的SOA生成研究进展,包括汽油蒸气VOCs、生物质燃烧VOCs和含氧VOCs形成SOA过程中,前体物浓度、芳香烃含量、无机气体、种子气溶胶和相对湿度(RH)等不同因素对SOA生成的影响;阐述了实际大气VOCs的SOA生成潜势及其影响因素,最后提出了目前在SOA机制研究方面存在的关键科学问题,并对未来的研究方向进行了展望.     

Synergistic cytotoxicity of binary combinations of inorganic and organic disinfection byproducts assessed by real-time cell analysis

Chlorine, chlorine dioxide, and ozone are widely used as disinfectants in drinking water treatments. However, the combined use of different disinfectants can result in the formation of various organic and inorganic disinfection byproducts (DBPs). The toxic interactions, including synergism, addition, and antagonism, among the complex DBPs are still unclear. In this study, we established and verified a real-time cell analysis (RTCA) method for cytotoxicity measurement on Chinese hamster ovary (CHO) cell. Using this convenient and accurate method, we assessed the cytotoxicity of a series of binary combinations consisting of one of the 3 inorganic DBPs (chlorite, chlorate, and bromate) and one of the 32 regulated and emerging organic DBPs. The combination index (CI) of each combination was calculated and evaluated by isobolographic analysis to reflect the toxic interactions. The results confirmed the synergistic effect on cytotoxicity in the binary combinations consisting of chlorite and one of the 5 organic DBPs (2 iodinated DBPs (I-DBPs) and 3 brominated DBPs (Br-DBPs)), chlorate and one of the 4 organic DBPs (3 aromatic DBPs and dibromoacetonitrile), and bromate and one of the 3 organic DBPs (2 I-DBPs and dibromoacetic acid). The possible synergism mechanism of organic DBPs on the inorganic ones may be attributed to the influence of organic DBPs on cell membrane and cell antioxidant system. This study revealed the toxic interactions among organic and inorganic DBPs, and emphasized the latent adverse outcomes in the combined use of different disinfectants.     

Formation of regulated and unregulated disinfection byproducts during chlorination and chloramination: Roles of dissolved organic matter type, bromide, and iodide

Algal blooms and wastewater effluents can introduce algal organic matter (AOM) and effluent organic matter (EfOM) into surface waters, respectively. In this study, the impact of bromide and iodide on the formation of halogenated disinfection byproducts (DBPs) during chlorination and chloramination from various types of dissolved organic matter (DOM, e.g., natural organic matter (NOM), AOM, and EfOM) were investigated based on the data collected from literature. In general, higher formation of trihalomethanes (THMs) and haloacetic acids (HAAs) was observed in NOM than AOM and EfOM, indicating high reactivities of phenolic moieties with both chlorine and monochloramine. The formation of haloacetaldehydes (HALs), haloacetonitriles (HANs) and haloacetamides (HAMs) was much lower than THMs and HAAs. Increasing initial bromide concentrations increased the formation of THMs, HAAs, HANs, and HAMs, but not HALs. Bromine substitution factor (BSF) values of DBPs formed in chlorination decreased as specific ultraviolet absorbance (SUVA) increased. AOM favored the formation of iodinated THMs (I-THMs) during chloramination using preformed chloramines and chlorination-chloramination processes. Increasing prechlorination time can reduce the I-THM concentrations because of the conversion of iodide to iodate, but this increased the formation of chlorinated and brominated DBPs. In an analogous way, iodine substitution factor (ISF) values of I-THMs formed in chloramination decreased as SUVA values of DOM increased. Compared to chlorination, the formation of noniodinated DBPs is low in chloramination.     

环境大气中半/中等挥发性有机物(S/IVOCs)的测量技术进展

总结了环境大气中半/中等挥发性有机物（S/IVOCs）的主要测量技术及其进展,重点介绍了基于气相色谱技术和化学电离质谱技术的测量方法.S/IVOCs的测量主要由气相色谱技术开始发展,并随着质谱技术的发展而不断发展.基于气相色谱技术的测量方法,能够直接测量非极性化合物,但在面对组分多达千万种的复杂体系时,传统的一维色谱相对耗时,而且由于峰容量不够,峰重叠现象十分严重,难以实现全组分的准确分离.新近发展的多维分离系统如全二维气相色谱,通过正交的分离系统,能够实现复杂体系中物种组分的准确、快速分离.目前基于化学电离质谱技术的在线测量方法已经逐渐应用于S/IVOCs的测量,虽然在物种定性方面相对较弱,但其可提供高时间分辨率的测量结果,帮助分析S/IVOCs在大气中的快速变化.在未来的研究中,高时间分辨率和全组分准确测量是S/IVOCs研究的关键.