Source characterization of fine and coarse particles at the East Mediterranean coast

Fine and coarse atmospheric particles were collected in Ashdod—a midsize industrial city on the southeastern Mediterranean coast, and in Gedera—a rural site, to characterize ambient particles and to determine their long-range transport during two major seasons—winter and summer. Manual PM2.5 and PM10 samplers, dichotomous samplers, continuous automated PM10 samplers, and denuders were used to sample particulate and gaseous pollutants.Fine and coarse concentrations in Ashdod were 21.2 and 39.6 μg m⁻³, and 23.9 and 30.5 μg m⁻³ in the fall–winter and summer campaigns, respectively. Crustal material, as calcites or dolomites mixed with silicates, dominated the coarse fraction and also the fine fraction on dusty days. In the fall–winter, S, P, and Ni were coupled with minerals. Coarse Ni was associated with crustal material during dust storms, while P originated from shipping and deposition of phosphates in the urban area around.Sulfates dominated the fine fractions in the summer season averaging 12 μg m⁻³. Multivariate analysis indicated that S was associated with As and Se, V and Ni, both associated with heavy fuel combustion, and Zn and Pb. In winter, those mixed sources were local, but in summer they were part of long-range transport. In the fall–winter, Zn and Pb were strongly associated with Mn, Ga, and Cu—elements emitted from either traffic or metal processing plants.Although the influence of crustal material on both size fractions was significant, most heavy metals were associated with PM2.5. Higher concentrations were linked to a larger number of particles in this fraction, to a larger surface area available for biochemical reaction [Harrison, R., Shi, J., Xi, S., Khan, A., Mark, D., Kinnersley, R., Yin, J., Philos, T., 2000. Measurement of number, mass and size distribution of particles in the atmosphere. Philosophical Transactions of the Royal Society 358, 2567–2579], and finally to a larger concern in regards to health effects.     

北京地区大气可吸入颗粒物中多环芳烃分布特征

采集北京城乡结合区和郊区冬季12个大气可吸入颗粒物不同粒径样品,用色谱-质谱技术分析鉴定了75种多环芳烃化合物,并对各粒径中美国EPA优控的16种多环芳烃做了定量分析,研究其在不同粒径的分布规律。结果表明:城乡结合区大气颗粒物中优控多环芳烃总量明显高于郊区;郊区和城乡结合区大气分别有68%和85%的优控多环芳烃吸附在粒径小于2 0μm颗粒物上;可吸入颗粒物中都相对富集高环数的多环芳烃;2个地区主要污染源可能为化石燃料的燃烧排放,燃煤的影响相对较大。      

黄河中下游水体中多环芳烃的分布及来源

对小浪底至山东东明段黄河干、支流水、悬浮物和沉积物进行了采样分析.结果表明,干流水相∑15PAHs浓度范围为179～369ng/L,其中除焦巩桥外其它断面苯并(a)芘均超过国家饮用水标准;支流水相浓度均高于相应干流,尤其是富含低环PAHs的孟州一干渠对干流沉积相浓度有较大影响.与水相相比,悬浮、沉积相中PAHs检出种类较多,干流悬浮相∑13PAHs浓度范围为54～155μg/kg,且各环PAHs与悬浮相中TOC含量间存在一定正相关.干流沉积相∑13PAHs浓度范围为31～133μg/kg,其4、5、6环P     

沙尘暴细颗粒物对人外周血淋巴细胞微核形成的影响

用胞质阻断微核试验法比较研究了内蒙古包头市和甘肃武威市沙尘暴和正常天气细颗粒物(PM2.5)及其无机与有机提取物对人外周血淋巴细胞微核形成的影响.结果表明本试验条件下,沙尘暴和正常天气PM2.5及其有机提取物均使淋巴细胞微核率(micronuclei frequency,MNF)显著增高,核分裂指数(nuclear division index,NDI)显著下降(p＜0.01),且存在剂量-效应关系,而无机提取物虽有剂量-效应关系,但各处理浓度之间及其与对照相比差异均不显著(p＞0.05);相同处理浓度下,除工业城市包头正常天气的PM2.5及其有机提取物处理的微核率显著高于沙尘(p＜0.01)外,沙尘暴和正常天气样品处理结果无显著差异(p＞0.05);城市之间相比,只有正常天气PM2.5及其有机提取物处理的微核率包头显著高于武威(p＜0.01),而沙尘暴PM2.5及其提取物的所有处理的微核率无城市间差异(p＞0.05).     

Relevant organic components in ambient particulate matter collected at Svalbard Islands (Norway)

n-Alkanes, polynuclear aromatic hydrocarbons and n-alkanoic acids present in the inhalable fraction of airborne particles have been determined at the Italian scientific base sited in the area of Ny Alesund, Spitzbergen Island, Norway. Both the profiles of n-alkane and polynuclear aromatic congeners among the respective classes showed that anthropogenic sources were responsible for the presence of particulate organics in the atmosphere there, since the monomodal distribution of aliphatics and the fresh-emission shape of PAH fraction were observed. The total contents of n-alkanes and PAH ranged from 19 to 97 ng m⁻³ and from 0.6 to 2.0 ng m⁻³, respectively; n-alkanoic acids reached 6 ng m⁻³. The occurrence of nitrated-PAH of photochemical origin at trace extent (i.e. nitrated-fluoranthenes and nitropyrenes) has been also observed. Since the occurrence of OH radicals is required together with NO_x for the processes leading to the generation of 2-nitrofluoranthene and 2-nitropyrene would start, the detection of these nitrated species revealed the occurrence of photochemical processes in that region.     

机动车排放颗粒物采集系统参数的研究和测试

机动车排放颗粒物是重要的空气污染物.笔者主要阐述了机动车排放颗粒物采集系统开发和研制过程中部分实验参数的研究和确定,同时给出了初步测试的结果,这些结果在一定程度上表征了机动车排入颗粒物的污染状况.      

交变电场中偶极荷电粒子电凝并的理论研究

根据碰撞理论 ,推导出偶极荷电粒子在交变电场中的电凝并系数 ,并利用 Williams求声凝并的方法 ,将其简化。若忽略粒子的惯性 ,则电凝并系数与交变电场的频率无关。     

Composition of the Saprotrophic Fungi in Calluna Heathland Soil and the Influence of Ammonium Nitrate Application

The composition of saprotrophic soil fungi in the mor layerof a Calluna-dominated, Danish heathland wasinvestigated after two years of fertilization with ammoniumnitrate (0, 35, 50 and 70 kg N ha^1- yr^-1) using asoil washing technique. The most frequently isolated generafrom the soil particles plated were Penicillium, Trichoderma, Mortierella and Mucor. Eightspecies of Penicillium were identified and Penicillium spinulosum was the most frequently isolated.The occurrence of dark, sterile fungi on the soil particleswas low. There were no measurable changes in the specificcomposition of the saprotrophic soil fungal groups due tothe nitrogen treatments, beside from an increasedoccurrence of Absidia californica. I conclude that adirect impact on the composition of the saprotrophic fungiin heathland soil is unlikely under enhanced nitrogen input.     

Comparison of Surface Organic Compound Mass Spectrum Patterns by LD-TOFMS for Megalopolis Atmospheric Particles and Diesel Exhaust Particles (DEP)

PM_2.5 and PM₁₀ samples for megalopolis atmospheric particles were collected at Shinjuku, Tokyo in December 1998–January 1999 and August 1999, for two weeks both in winter and summer, with a 24 hr sampling interval. Sampling of PM_2.5 and PM₁₀ in diesel exhaust particles (DEP) was carried out using an automobile exhaust testing system, with a diesel truck placed on a chassis dynamometer. Sampling conditions included idling, constant speed of 40 km hr^-1, M-15 test pattern and 60%-revolution/40%-load of maximum power. Mass spectrums of organic compounds adhering to the surface of the PM_2.5 and PM₁₀ samples were analyzed by laser desorption time-of-flight mass spectrometry (LD-TOFMS, analytical mass range: m/z 1–m/z 380 000). LD-TOFMS analysis of those samples revealed consistently the detection of low-mass organic compounds up to m/z 800. For the megalopolis atmospheric particles, the mass spectrum pattern of wintertime samples was almost the same as that of the summertime samples for both PM_2.5 and PM₁₀. The major peak was m/z 177, and the minor peaks were m/z 84, 94, 101, 163, 189 and 235. The mass spectrum pattern of DEP was the same for all samples under all test conditions. The major peak was m/z 101, and other detected peaks were small.     

Removal of phenol by activated alumina bed in pulsed high-voltage electric field

A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe^2＋. The removal rate of phenol could reach 72.1% when air aeration flow rate was 1200 ml/min, and 88.2% when 0.05 mmol/L Fe^2＋ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.