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711.
Kentaro Murano Hitoshi Mukai Shiro Hatakeyama Eun Suk Jang Itsushi Uno 《Atmospheric environment (Oxford, England : 1994)》2000,34(29-30)
Observations of air pollutants were conducted in remote Japanese islands (Oki Island and Okinawa Island) in early spring to clarify the extent of trans-boundary air pollution from the Asian continent. A three-dimensional Eulerian model calculation, which included parameters on emission, transport and transformation of sulfur oxides, nitrogen oxides and ammonia, was performed to compile sulfate isosurface concentrations over the observational sites. Concentrations of non-sea-salt sulfate (nss-SO42−) of greater than 10 μg m−3 were observed at Oki after the northeastward passage of low-pressure systems in the Sea of Japan. At these times, the weather showed a typical winter pattern and air pollutants over China were transported southeastward to Japan with the northwesterly wind. The model calculation reproduced the observed variations of nss-SO42− concentration well, except for one case in which the model calculation could not reproduce the extremely low nss-SO42− concentration observed on 8 March. In Hedo (Okinawa Island), we observed long-lasting (3 days) medium concentrations of nss-SO42− (approximately 5 μg m−3). Although the model reproduced these observed medium concentrations well, in general the observed results were reproduced better for Oki than for Hedo. Under the synoptic weather conditions of early spring, high concentrations of nss-sulfate were sometimes transported to these remote Japanese islands from areas of continental Asia with a strong outflow of air pollutants. 相似文献
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该文评价了克拉玛依市区的大气环境质量现状,并分析了大气污染的主要特征及其产生的原因,得出了相应结论:市区的大气污染以尘 污染为主,主要污染物是降尘和总悬浮颗粒物,最后提出了一些具体的防治对策。 相似文献
717.
区域持久性有机物的健康风险评价方法研究 总被引:15,自引:9,他引:6
随着城市和工业的发展,工业点源和机动车排放了大量有毒污染物,加剧了城市居民的健康风险.在传统的健康风险评价的基础上,提出了区域持久性有机物的健康风险评价思想,并对研究方法进行了初步探讨.在GIS的环境中,集成了ISCST3(复杂工业源扩散模型)和传统风险评价中的多种风险源累积的风险评价模型,建立起以GIS为基础的RHRA(区域健康风险评价方法).以上海市杨浦区为例,根据当地的气象条件和区域污染源的分布情况,对由该区域固定源和移动源排放的有毒污染物引起的区域人类致癌风险和非致癌风险进行了研究.结果表明:杨浦区的致癌风险值为500~1.0×104,非致癌风险指数为1.32~85.70.模拟得到有毒污染物产生的健康风险等值线图显示,区域中健康风险的大小与道路机动车流量和工业点源的分布高度相关. 相似文献
718.
Radon has been determined in soil, groundwater, and air in Mexico, both indoors and outdoors, as part of geophysical studies
and to estimate effective doses as a result of radon exposure. Detection of radon has mainly been performed with solid-state
nuclear track detectors (SSNTD) and, occasionally, with active detection devices based on silicon detectors or ionization
chambers. The liquid scintillation technique, also, has been used for determination of radon in groundwater. The adjusted
geometric mean indoor radon concentration (74 Bq m−3) in urban developments, for example Mexico City, is higher than the worldwide median concentration of radon in dwellings.
In some regions, particularly hilly regions of Mexico where air pollution is high, radon concentrations are higher than action
levels and the effective dose for the general population has increased. Higher soil radon levels have been found in the uranium
mining areas in the northern part of the country. Groundwater radon levels are, in general, low. Soil-air radon contributing
to indoor atmospheres and air pollution is the main source of increased exposure of the population. 相似文献
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720.
Degradation of H-acid in aqueous solution by microwave assisted wet air oxidation using Ni-loaded GAC as catalyst 总被引:5,自引:2,他引:3
A novel process, microwave assisted catalytic wet air oxidation( MW-CWO), was applied for the degradation of H-acid( l-amino8-naphthol-3, 6-disulfonic acid) in aqueous solution, Ni-loaded granular activated carbon (GAC), prepared by immersion-calcination method, was used as catalyst. The results showed that the MW-CWO process was very effective for the degradation of H-acid in aqueous solution under atmospheric pressure with 87.4% TOC (total organic carbon) reduction in 20 min. Ni on GAC existed in the form of NiO as specified by XRD. Loss of Ni was significant in the initial stage, and then remained almost constant after 20 min reaction. BET surface area results showed that the surface property of GAC after MW-CWO process was superior to that of blank GAC. 相似文献