大气CO2浓度升高对农田土壤颗粒组成及其碳周转的影响

采集FACE(Free Air CO2 Enrichment)平台下运行3年的水稻(Oryza sativaL.)/小麦(Triticum aestivumL.)轮作土壤(0~15cm耕作层土壤),利用超声波分散-湿筛分法对烘干土样进行颗粒分级,分析土壤各粒级及其碳、氮的分布特征,研究大气CO2浓度升高对土壤碳周转的影响。结果表明:高浓度大气CO2条件下稻/麦轮作3年后,土壤颗粒组成较对照发生了改变,>53μm粒级的质量分数减小27%(p<0.05),约占土壤总质量20%;53~25μm粒级的质量分数增大35%(p<0.05),约占土壤总质量25%;<25μm无明显变化,约占土壤总质量55%,三种粒级之间质量分数呈显著差异(p<0.05)。FACE条件下,不同粒级土壤颗粒碳质量分数在两个氮水平下平均为:>53μm(30.60g·kg-1),<25μm(13.08g·kg-1),25~53μm(12.85g·kg-1),氮质量分数分别为2.42g·kg-1,1.33g·kg-1,1.12g·kg-1。>53μm粒级的土壤颗粒碳、氮质量分数均极显著高于其它两个粒级(p<0.001)。FACE条件下土壤总碳、氮质量分数高于对照,增幅分别为6.2%和6.7%。从各粒级土壤颗粒碳、氮质量分数变化分析,新增碳、氮主要进入>53μm粒级中,表明该粒级土壤颗粒对土壤碳氮循环(转化和保存)起着重要作用。该研究结果表明高浓度大气CO2条件下,稻/麦轮作农田土壤将成为大气CO2的汇,这将为预测我国未来农田土壤碳的变化趋势提供科学依据。     

三种空气微生物采样方法的比较

在室内自然条件下，对三种空气微生物采样方法进行比较。结果表明，ＡＮＤＥＲＳＥＮ采样器法，ＬＷＣ－１笄样器法和平皿沉降法测定的室内空气微生物粒子浓度分别为２６３４个／ｍ＾％３，２３９５个／ｍ＾３和１３８０个／ｍ＾３，ＬＷＣ－１型和ＡＮＤＥＲＳＥＮ二种采样器的采样结果之间没有明显差异，二种采样器的采样结果均明显高于平皿沉降法的采样结果。ＡＮＤＥＲＳＥＮ采样器的采样效率高，且可同时测定空气微生物粒子的浓     

光子相关光谱（PCS）在无机高分子絮凝剂形态表征中的应用

本文运用现代先进的微粒检测手段光子相关光谱对常见的两类无机高分子絮凝剂的形态进行了表征。实验结果表明：在所测聚合氯化铁溶液中，体系呈较为单一的集中分布，由平移扩散系数计算得到平均有效直径在５－１１ｎｍ左右。在所测聚合氯化铝溶液中，主要为双峰分布，熟化后样品约为２－５ｎｍ的小颗粒与数十ｎｍ以上分布较宽的聚集体，另外，本文对光子相关光谱在形态表征中的优缺点及其它应用的可能性也作了一定的论述。     

复合生态处理系统颗粒构成差异及其效应分析

研究了复合生态处理系统中不同单元颗粒物的构成差异，探讨了颗粒构成对其去除机制、粒径分布和去除规律的影响．结果表明，水环境对系统后端颗粒构成产生的影响明显高于对系统前端的影响．颗粒构的成差异决定无机颗粒沉降，有机颗粒分解、藻类被捕食、颗粒截滤依次在颗粒物的去除中占主导地位．不同水环境中，颗粒构成和去除机制的差异导致不同单元颗粒物去除规律的相应变化．     

Evaluation of PCDD/F congener distributions in MWI flue gas treated with SCR catalysts

Partitioning of PCDD/F congeners between gaseous and particulate phases and removal efficiencies of the air pollution control devices (APCDs) for PCDD/Fs at an existing municipal waste incinerator (MWI) in Taiwan are evaluated via stack sampling and analysis. The MWI investigated is equipped with electrostatic precipitators (EP), wet scrubbers (WS) and selective catalytic reduction system (SCR) as APCDs. The average PCDD/F concentration of stack gas is 1.49 ng/N m³, and the International Toxic Equivalent Quantity (I-TEQ) is 0.043 ng-I-TEQ/N m³. The EP increases PCDD/F concentration by 174.0% while the average removal efficiency of WS + SCR system for PCDD/Fs reaches 99.1%. In addition, the PCDF removal efficiency achieved with WS + SCR system (97.1–99.8%) is higher than that for PCDDs (96.5–99.3%). The results obtained on gas/particulate partitioning in flue gas indicate that the particulate-phase PCDD/Fs accounted for 65% at the inlet of EP, 20% at the outlet of EP and 50% at the stack, respectively, of the total PCDD/F concentrations. This study also indicates that as the chlorination level of PCDD/F congeners increases, the percentage of PCDD/Fs existing in gas phase decreases in all flue gas samples.     

机动车尾气中颗粒物对人体健康的危害

本文介绍了燃油机动车在不同运行状况下排放颗粒物的情况;以及不同粒径颗粒物与其它环境空气中污染物协同作用对人体健康的危害.     

内蒙古西乌珠穆沁旗伏沙地土壤环境粒度特征分析

通过对西乌珠穆沁旗境内不同类型伏沙地的土壤剖面特征和土壤粒径的分析认为:伏沙地土壤具有两层结构,其平均粒径大于地带性土壤.腐殖质层从上至下的粒径变化是先减小后增大.由松散的沙物质组成的母质层能够提供充足的水分,促进了矿物质的循环,使伏沙地的养分输出加快,不利于积累.良好的通气状况便有机物质矿化速度加快,不利于腐殖质的积累.     

立窑小水泥厂适用除尘方法的研究

为了提供立窑小水泥厂的适用除尘方法，作者对几个小水泥厂系统地测定了主要工序排出粉尘的粒径分级组成和相应的粉尘浓度、烟气温度和含湿量等参数；测定了重力沉降室、旋风除尘器、冲击水浴除尘器、冲击———喷雾除尘器的粒径分级除尘效率。在此基础上，将污染源和除尘器进行匹配，对各工序所宜采取的除尘方案进行科学论证，提出的方案更为切合实际。     

太原市气悬颗粒物上多环芳烃的测量与分布研究

2 0 0 1年 3月下旬 ,在太原市建成区均匀布设 1 5个网格点 ,利用新型便携式仪器 ,连续 5天监测了各点大气颗粒物上多环芳烃 (PPAHs)的浓度。结果表明 ,PPAHs浓度范围为 3 6ng/m3～ 3 1 3 ng/m3;全市上下午平均浓度为 1 3 9ng/m3;上午浓度平均值是下午的 2倍 ;全市空间分布整体上由北向南逐渐降低 ,东北部最重 ,东南部最轻 ;不同功能区的污染程度依次为 :一电厂化工区 >太钢工业区 >桃园商业区 >太行居民区。本文还着重探讨了污染分布的成因 ,并提出了改善大气质量的建议。     

Characterisation of particulate matter emissions from the Zimbabwe Mining and Smelting Company (ZIMASCO) Kwekwe Division (Zimbabwe): a ferrochrome smelter

Particulate matter emissions from stack number 2 of a majorferrochrome smelter, Zimbabwe Mining and Smelting Company(ZIMASCO) were characterized and the rates at which the elementsCr, Fe, Cu and Zn and total ferrochrome dust are emitted into theatmosphere were determined. The extent of soil contamination bythe dust deposited around the smelter in the generally prevailingsoutheasterly wind direction around the smelter was carried out.The highest concentrations of Cr and Fe occurred in the fineparticulates of sizes less than 59 m whilst that of Cu and Znoccurred in the coarse particulates of size range 70-100 m.The emission rates from stack 2 were; total ferrochromeparticulates 62.17 kg h^-1, Cr 6.217 kg h^-1, Fe 2.423 kg h^-1, Zn42 mg h^-1 and 6 mg h^-1 for Cu. Particulate matter was emitted at arate of 289 mg m^-3 from stack number 2. This value exceeds thelegal limit of 200 mg m^-3. Chromium and iron are the metalsin the largest amounts. The particles that constitute the largestproportion of the dust were in the range of 58-107.5 m. Thisis a characteristic feature of the particulate matter emissionsfrom ZIMASCO. Soils in the downwind direction from the smelterwere polluted with Cr up to a distance of about 700 m outward fromthe perimeter of the boundary of the smelter.