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991.
992.
四城市空气粗、细颗粒物元素质量谱及富集特征 总被引:3,自引:0,他引:3
以武汉市 X荧光光谱分析数据为例 ,介绍了粗、细颗粒物中元素的质量谱及富集特征。并且 ,比较了广州、武汉、兰州、重庆四城市的污染元素及可能污染元素的某些富集特征 相似文献
993.
Arkian F Salahinejad M Bidokhti AA Meshkatee A 《Environmental monitoring and assessment》2008,140(1-3):325-330
Measurement of gross α, gross β activities and cosmogenic beryllium-7 (7Be) concentrations were made both daily and weekly during the years 2001–2004 from samples of atmospheric aerosols filtered
from the air at Tehran Nuclear Research Center (35 41′ N) and Zahedan (28 29′ N). Weekly aerosol samples collected with the
high-volume air samplers on cellulose filters were used to determine the 7Be contents of samples, using a semiconductor gamma spectrometer. Airborne dust samples were collected daily on fiber glass
filters and used to determine the gross β and gross α activities with automatic beta analyzer and a ZnS(Ag) counter, respectively.
In this work, the concentration and meteorological data were used to determine models for gross α, gross β and 7Be. The air concentrations of gross β and gross α activities and 7Be concentrations displayed lognormal distributions during the study period. Both β and 7Be have maximum activity concentrations during warm mid-year months. 相似文献
994.
995.
Ian Colbeck Zaheer Ahmad Nasir Shahida Hasnain Sikander Sultan 《Water, Air, & Soil Pollution: Focus》2008,8(1):61-69
In the developing world, the vast majority of people rely on solid biomass fuels for cooking and heating which results in
poor indoor air quality. The present study determined indoor air quality in some rural and urban areas of Pakistan. Measurements
were made of particulate mass (PM10, PM2.5 and PM1), number concentration and bioaerosols in different micro environments.
PM10 concentrations of up to 8,555 μg/m3 were observed inside the kitchens where biofuels were used as energy source. Cleaning and smoking was identified as a major
source of indoor particulate pollution and concentrations of more than more than 2,000 μg/m3 were recorded in the living room during these activities. Indoor number concentrations in Lahore were typically greater than
those observed outdoors in European cites. At a rural site the highest Colony Forming Units (CFUs) were in the 0.5 μm–2 μm
size fraction, while at the urban location CFUs were dominant for 2 μm–16 μm. It was observed that CFUs(Colony Forming Units)
counts were higher inside living rooms than kitchens. It is important to note that women and children were exposed to extremely
high levels of particulates during cooking. Overall, indoor air quality in Pakistan was poor and there is a dire need to take
a serious step to combat with it. 相似文献
996.
Laboratory longitudinal diffusion tests: 1. Dimensionless formulations and validity of simplified solutions 总被引:1,自引:1,他引:0
To obtain reliable diffusion parameters for diffusion testing, multiple experiments should not only be cross-checked but the internal consistency of each experiment should also be verified. In the through- and in-diffusion tests with solution reservoirs, test interpretation of different phases often makes use of simplified analytical solutions. This study explores the feasibility of steady, quasi-steady, equilibrium and transient-state analyses using simplified analytical solutions with respect to (i) valid conditions for each analytical solution, (ii) potential error, and (iii) experimental time. For increased generality, a series of numerical analyses are performed using unified dimensionless parameters and the results are all related to dimensionless reservoir volume (DRV) which includes only the sorptive parameter as an unknown. This means the above factors can be investigated on the basis of the sorption properties of the testing material and/or tracer. The main findings are that steady, quasi-steady and equilibrium-state analyses are applicable when the tracer is not highly sorptive. However, quasi-steady and equilibrium-state analyses become inefficient or impractical compared to steady state analysis when the tracer is non-sorbing and material porosity is significantly low. Systematic and comprehensive reformulation of analytical models enables the comparison of experimental times between different test methods. The applicability and potential error of each test interpretation can also be studied. These can be applied in designing, performing, and interpreting diffusion experiments by deducing DRV from the available information for the target material and tracer, combined with the results of this study. 相似文献
997.
固定化生物活性炭处理低浓度甲醇废水 总被引:11,自引:0,他引:11
将分离筛选得到的甲醇降解菌固定在颗粒活性炭上,组成固定化生物活性炭反应系统,研究该反应系统处理轻度污染含甲醇废水的最佳运行条件和运行效果,结果表明,固定化生物活性炭处理轻度污染含甲醇放心水的方法明显好于3种树脂和单纯活性炭吸附处理,反应系统的最佳运行条件是水力负荷0.84-0.77m^3(m^2.h),停留时间57-62min,pH7-8,温度20℃-30℃,溶解氧是去除甲醇的主要限制因子,甲醇含量为11.3-23.1mg/L时,去除率大90%,出水CODcr小于12mg/L。此外还研究了生物活性炭生物膜的一些特点,并分析了运行中活性炭吸附性能的变化。 相似文献
998.
对不同浓度KCl和不同pH下,3种可变电荷土壤和4种恒电荷土壤Cl-吸附量进行了测定。结果表明,土壤Cl-吸附量随平衡Cl-浓度C(e)增加而增大,恒电荷土壤呈线性,可变电荷土壤在添加Cl-0.5~5.0mmol/L下,符合Langmuir吸附等温式。同一浓度下的Cl-吸附量及其随浓度增加的速率均为砖红壤>红壤>赤红壤>黄棕壤>棕壤、暗棕壤和黑土,与这些土壤所带正电荷量顺序相一致。Langmuir方程K值较小且几种土壤差异不大。恒电荷土壤对Cl-的吸附量很小,在浓度较低时常出现负吸附,其吸附机理可能更多的是与K+吸附时的同时吸附。7种土壤Cl-吸附量均随pH增加而降低,但降低强度可变电荷土壤远大于恒电荷土壤。 相似文献
999.
Vanderstraeten P Lénelle Y Meurrens A Carati D Brenig L Offer ZY 《Environmental monitoring and assessment》2007,132(1-3):253-262
We report and analyze data on the PM10 fraction of airborne particles measured at five recording stations in the Brussels
region from October 2002 till September 2003. These stations are representative of the various activity sectors of the Brussels
urban area. The objective was the determination of the origin of the PM10 particles (particles up to 10 μm) that are recorded
in that region in order to follow the EU directives concerning tolerance level of airborne particles concentration. In order
to evaluate the impacts of local and external factors that inject solid particles in the atmosphere of Brussels we compared
concentration data from working and not working (holidays) periods. Moreover, we also compared concentrations from periods
of agricultural activity and rest in the Brabant provinces surrounding the Brussels region for various crop types. The results
lead to the conclusion that the impact or urban traffic is rather limited while that of the agricultural activities is important.
Moreover, there appears a clear-cut distinction between different types of crops. 相似文献
1000.
The study aimed to explore if changes in crown defoliation and stem growth of Scots pines (Pinus sylvestris L.) could be related to changes in ambient ozone (O3) concentration in central Europe. To meet this objective the study was performed in 3 Lithuanian national parks, close to the ICP integrated monitoring stations from which data on meteorology and pollution were provided. Contribution of peak O3 concentrations to the integrated impact of acidifying compounds and meteorological parameters on pine stem growth was found to be more significant than its contribution to the integrated impact of acidifying compounds and meteorological parameters on pine defoliation. Findings of the study provide statistical evidence that peak concentrations of ambient O3 can have a negative impact on pine tree crown defoliation and stem growth reduction under field conditions in central and northeastern Europe where the AOT40 values for forests are commonly below their phytotoxic levels. 相似文献