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771.
This study examined the levels of seven heavy metals (namelyzinc, copper, cadmium, chromium, lead, manganese and iron) andtheir associations with magnetic properties in playground dustof Hong Kong. Results showed that the playground dust containedhigh concentrations of Zn (mean = 1883 g g-1), Cu(mean = 143 g g-1) and Cr (mean = 263 g g-1).Qualitative examination of dust samples under microscope indicated local traffic as one of the important pollutant sources. Magnetic measurements indicated that these anthropogenicpollutants mainly consisted of coarse-grained multidomain (MD) ferrimagnetic minerals. Superparamagnetic (SP), stable single domain (SSD) ferrimagnetic grains and non-ferrimagnetic mineralswere present in relatively small amounts. Significant correlations between heavy metals and various magnetic parametersindicated a strong affinity of heavy metals to magnetic minerals hence pointed out the potential of magnetic properties for simpleand rapid proxy indications of heavy metal pollution in playground dust. 相似文献
772.
773.
硼作业工人的空气粉尘暴露与硼暴露测量与评价 总被引:3,自引:0,他引:3
报告了硼作业工人与对照人群的个人空气粉尘暴露浓度、空气硼暴露浓度以及通过空气的日硼暴露量.结果表明,硼作业工人的两次(间隔4周)空气粉尘暴露浓度分别为19.2mg/m3和21.0mg/m3,空气硼暴露浓度分别为516μg/m3和797μg/m3,8小时空气硼暴露量为2.58mg和3.98mg;而对照组的这三类值分别为0.53mg/m3、1.87μg/m3和0.009mg.各类人群的日空气硼暴露量随工作环境的不同而有很大差异,井下采矿、原料车间、成品车间、生产管理人员的日空气硼暴露量分别为1.58mg、5.55mg、0.98mg、0.14mg,高出对照组几十倍至几百倍. 相似文献
774.
Assessment of the Status of Urban Air pollution And Its Impact on Human Health in the City of Kolkata 总被引:1,自引:0,他引:1
Air pollution has significant effects on exacerbation of asthma, allergy and other respiratory diseases. Like many other magacities in the world the ambient air quality of Kolkata is also being deteriorated day by day. Automobile exhausts and certain industrial pollutants produce O3 by photochemical reactions. The particulate matter, particularly less than 10 μ in size, can pass through the natural protective mechanism of human respiratory system and plays an important role in genesis and augmentation of allergic disorders. Sources of air pollution in the area and the unique problem arising out of the emission from the vehicles, industries, etc. have been described. Ambient air quality was monitored along with micrometeorological data and the results are discussed. The status of air pollution in the area has been evaluated and a questionnaire survey was conducted to estimate the allergic symptoms and exposure to assess the respiratory disorders. The data are analysed to evaluate the critical situation arising out of the emission of air pollutants and the impact on human health due to respirable diseases (RDs) to middle class sub-population (activity-wise) in the area are assessed. A strategic air quality management plan has been proposed. For the mitigation of air pollution problems in the city, the different measures to be adopted to maintain the balance between sustainable development and environmental management have been discussed. 相似文献
775.
Instrumentation used to measure characteristics of fine particles entrained in gas or suspended in aerosols provides information needed to develop valid regulations for emission sources and to support the design of control technologies. This case study offers a brief history of micromeritics, a term used by early researchers to describe the science of small particles, and the related invention of laboratory instruments for characterizing very fine particles. The historical view provides insights into the role that Progressive Era government agencies played in advancing esoteric science and applying this knowledge to the regulation of workplace air pollution. Micromeritics instrumentation developed in conjunction with federal research now has many commercial applications worldwide, with characterizing airborne pollutants only a minor one. However, the continuing advances in the micromeritics field provide important laboratory measurement capabilities to environmental research organizations, such as the National Institute for Occupational Safety and Health (NIOSH). 相似文献
776.
茶尘(大叶种)分散度的测定 总被引:1,自引:0,他引:1
论述了利用图像分析系统对茶尘(大叶种)分散度的测定,得到了分散度的结果,并对测定结果进行了讨论. 相似文献
777.
碳酸盐碳测定在沙尘暴来源地识别中的应用 总被引:7,自引:0,他引:7
根据中国大气颗粒物特点 ,在国内沙尘暴研究中首次尝试利用碳酸盐碳进行沙尘暴来源地识别。测定了一系列黄沙、大气颗粒物和沙尘暴源区土壤样品。初步了解了上述样品中碳酸盐碳含量情况 ,结合国外研究结果对影响北京的沙尘暴源区进行推测并与其他方法作了比较 相似文献
778.
电除尘器粉尘层反电晕击穿厚度理论与试验 总被引:1,自引:0,他引:1
为了合理地确定静电除尘器清灰振打周期,通过理论与试验方法确定静电除尘器粉尘层反电晕击穿厚度很有必要的。首先基于静电学理论导出带电粉尘层内的电量分布和电场分布数学模型,然后根据粉尘层反电晕发生条件,得出粉尘层反电晕击穿厚度的计算式,结果表明,反电晕击穿厚度是粉尘比电阻、电晕电流密度及极配的函数。通过对高比电阻不同厚度的粉尘层的反电晕击穿试验研究,结果表明,各击穿点的连线呈较连续光滑的弧线,提出了利用伏安特性曲线确定粉尘层反电晕击穿厚度的简易图解法。 相似文献
779.
目前普遍使用的民用锅炉湿式除尘器多是不加碱性脱硫剂,而以清水作脱硫液,其SO2排放更集中,出口SO2浓度有时比人口还高,并排放大量酸性水蒸汽。用碱作脱硫荆运转费用大,管理部门很难监控企业加碱性脱硫剂。 相似文献
780.
通过对湖北田力实业股份有限公司麻石(文丘里)水膜除尘工艺在沸腾炉烟气除尘中存在的问题进行研究和分析,对(文丘里)水膜除尘工艺进行了改进。采用加装U型布水装置和采取间歇性用水冲刷灰垢的措施,解决了烟道内壁水、气界面处的结垢问题,替换了人工除垢,且烟尘排放浓度达到了环保要求,其回收的烟尘通过外销又取得了经济效益。 相似文献