鞍山市大气尘和金属元素沉降通量及污染特征

通过采集鞍山市11个点位的降尘样品以及土壤样品,用ICP-MS分析了Cu、Mn、Zn、Pb等元素含量,并计算其沉降通量。结果表明,鞍山地区大气降尘的沉降通量为2.92～59.8g/(m2.month),其中鞍钢厂区沉降通量均值为31.6g/(m2.month),分别是周边地区和对照地区的4.72倍和10.5倍。重金属As、Cr、Pb和Cd的沉降通量分别为3.78、45.5、42.8、0.457g/(hm2.month)。降尘中各元素的富集系数为0.29～190,其中Cu、Fe、Zn、Mo、Cd、Pb和Se的富集系数大于10,说明这些元素主要来自于人为源。鞍钢厂区土壤中Cu、Pb、Mn、Zn、Mo、Cd、Ca、Fe和Se的含量较辽宁省土壤背景值高,说明其土壤环境已经受到了人类活动的影响。     

临安大气本底站酸雨污染变化特征与影响因素分析

利用临安大气本底站酸雨观测数据,研究临安大气本底站降水pH,酸雨发生频率的时间分布特征、变化趋势及其影响因素;借助后向轨迹分析法分析输送形势对临安大气本底站酸雨的影响。研究表明:最近6年间临安大气本底站降水pH各月均值均小于4.5,均达到强酸雨的程度;临安大气本底站的酸雨发生频率表现为夏季低、秋季高;1985—2009年临安大气本底站降水的年均pH全部达到酸雨程度。根据Daniel趋势检验,临安大气本底站年均降水pH总体上呈逐年下降的趋势。风速越小,酸雨出现频率就越高;降水pH受降水量的影响较大。临安大气本底站的酸雨与降水前的大气中SO2浓度存在负相关的关系。根据气团的来向与酸雨污染程度的关系分析,临安大气本底站的酸雨污染受到其北部地区和浙西地区的酸雨气体物输送的影响较大。临安大气本底站的酸雨污染特征已由原来的硫酸型转为硫酸型与硝酸型并重。     

南通市某钢丝绳行业集中区降尘中重金属污染状况评价

针对南通市钢丝绳行业集中区重金属污染问题,分析降尘中的铅、镉、铬、铜、镍、铁、锌、锰等重金属含量,并采用污染指数法和地累积指数法对降尘中重金属污染状况进行评价。结果表明,该集中区降尘中重金属污染程度依次为Zn>Pb>Cd>Cu>Fe>Mn>Ni>Cr,铅、锌为主要污染因子,铅、锌污染级别均处于重污染级别。     

环境空气污染物预测浓度与环境背景值叠加应注意的问题

着重阐述了建设项目环境影响评价中环境空气污染物的预测值和背景值相加必须具备的条件 ,得出了在大气环境影响评价中一、二类评价的叠加及三类评价的操作方法。     

Management of hazardous road derived respirable particulates using magnetic properties of tree leaves

The magnetic properties of tree leaves along with their ecological, economical and aesthetic importance can be used to control road derived respirable particulates. Isothermal remanent magnetization (IRM₃₀₀ mT) of three different tree leaves viz. Mango (Mangifera indica), Sisso (Dalbergia sisso) and Banyan (Ficus benghalensis) were determined and IRM₃₀₀ mT normalized for the leaf area. The normalized 2-D magnetization of leaves as shown by results is dominantly controlled by leaf morphology and traffic density. F. benghalensis (Banyan) leaf has highest 2-D magnetization and D. sisso (Sisso) leaf having least 2-D magnetization suggesting greater ability of F. benghalensis (Banyan) tree leaves to reduce magnetic particulates. The particle size of the magnetic grains falls in the category of PM2.5, a particle size hazardous to human health due to its capacity to be inhaled deeply into the lungs.     

大气污染扩散的高斯烟羽模型及其GIS集成研究

以VB6结合SuperMap Objects 5.2为开发平台,实现高斯烟羽模型与GIS的集成,可视化地表达大气污染物的扩散过程,并通过实例讨论了GIS与烟羽模型集成的方法、技术流程及其他相关问题.     

图们市大气颗粒物中重金属含量及分布特征

采集了图们市2006年秋、冬两季的TSP和PM10样品,采用湿法消解-原子吸收分光光度法测定了其中的铅、镉、饲、锌、铬、铁、锰7种重金属.结果表明,图们市大气颗粒物中重金属含量由高到低的顺序是Fe>Cr>Zn>Pb>Mn>Cu>Cd.多数重金属元素含量冬季高于秋季,在一天之内早晨的重金属浓度也往往高于晚上争中午,说明大气颗粒物的来源包括天然源和人为源.     

上海市浦东新区大气降水化学组分及其相关性分析

依据上海市浦东新区2010—2015年2个代表性采样点的142份监测数据,对降水中的化学组成及各组分间的相关性进行了分析。结果表明,监测期间单次降雨的pH值为3.85~6.09,平均值为5.09,属硫酸型/硝酸型复合污染酸雨。其中SO_4~(2-)和NO_3~-为主要离子,平均值分别为4.55和3.31 mg/L。通过SPSS统计分析得出,人类生活和生产过程以及海洋源是浦东新区大气降水化学组分的主要来源,但仍存在不同的区域特征。     

江苏省水泥制造业经济发展与大气环境变化相关性分析

选取了2001—2014年的相关数据,分析了江苏省水泥制造业的经济发展、资源能源消耗和污染物排放特征,同时对行业经济发展与大气环境污染变化进行了相关性分析。结果表明,2001—2014年,江苏省水泥制造业工业总产值呈现波动增加趋势,工业煤炭消费量呈现波动增加趋势,投入产出比呈现逐年波动上升态势;SO2的排放强度呈现波动下降的趋势,低于全省平均水平;烟粉尘的排放强度波动下降,高于全省平均水平;NOX的排放强度呈现波动上升的趋势,高于全省平均水平;SO2与烟粉尘排放量与GDP均高度呈负相关,回归曲线模拟基本类似U型的左半段,随着GDP的增加,SO2和烟粉尘的排放量呈现下降趋势。     

The oxidation mechanism of polychlorinated dibenzo-p-dioxins under the atmospheric conditions - A theoretical study

The atmospheric polychlorinated dibenzo-p-dioxins (PCDDs) partition appreciably in the gas phase, where they undergo rapid oxidation. The atmospheric oxidation mechanisms of a few PCDDs, initiated by OH radical, are studied using density functional theory calculations. The oxidations start with OH-addition to the aromatic rings, dominantly at γ-sites, followed by the non-chlorinated β-sites; while additions to the α-sites or chlorinated sites are negligible. For PCDDs with all β-sites being chlorinated, formation of PCDD-γ-OH adducts become virtually the only reaction path. Under the atmospheric conditions, the PCDD-β/γ-OH adducts combine with O₂ slowly at rates <1 s⁻¹. Instead, the PCDD-β-OH adducts will react with O₂ through hydrogen abstraction at rates <50 s⁻¹, forming PCDD-β-ol, and the PCDD-γ-OH adducts will decompose to the substituted phenoxy radicals by fused-ring C-O bond cleavage at rates of 10³ ∼ 10⁵ s⁻¹. The reaction mechanisms of PCDDs are drastically different from the peroxy mechanism for the atmospheric oxidations of benzene and dibenzofuran.