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111.
Space shuttle launches produce localized hydrochloric acid deposition. The interaction of solid rocket motor exhaust and deluge
water released on the pad at the time of launch results in the formation of an exhaust cloud. The spatial pattern and extent
of deposition from the launch cloud are predicted by the rocket exhaust effluent diffusion (REED) model. The actual pattern
of deposition has been mapped by field surveys for each shuttle launch since 1981. In this paper we use a geographical information
system (GIS) to compare model predictions with ground patterns for 49 shuttle launches. We also compile cumulative maps of
deposition patterns needed to consider long-term impacts. The direction of launch cloud movement did not differ significantly
from model predictions. The REED model overpredicted both the area that received deposition and the maximum distance from
the launch pad that deposition occurred. Severe vegetation damage was restricted to near-field deposition areas within 1980
m north of each launch pad. Total area impacted from launches has been 87.0 ha around pad 39A and 52.9 ha around pad 39B.
Far-field deposition has caused leaf spotting from acid droplets or aluminum oxide over a wider and more variable area than
near-field. A total of 19,397 ha has received deposition, but 63.6% of this area has received deposition only one time and
92.2% not more than three times. GIS techniques provide means to test spatial models and compile information useful for assessing
cumulative impacts. 相似文献
112.
The sulphur dioxide and nitrogen oxides emissions from all sources in Alberta, Canada, during 1982 amounted to 488,297 and 353,511 tonnes, respectively. During this year deposition of wet sulphate from all stations in the province, 8 kg ha–1 yr–1, compares well with the five-year average (1978–1982) value of 10 kg ha–1 yr–1. These measurements are about one-half of the wet sulphate deposition criteria of 20 kg ha–1 yr–1 established for protecting the moderately sensitive aquatic ecosystem in eastern Canada. Due to dry, cold, continental climate conditions of Alberta, dry sulphate or sulphur deposition is equally or more important than wet deposition. No effects of the long-range transport of atmospheric pollutants (LRTAP) on the ecosystems in Alberta have been observed to date. Atmospheric deposition target loadings of SO4
–2, NO3
–, and H+ for Alberta and western Canadian environmental conditions should be developed to protect the highly sensitive ecosystems. Some future research and monitoring priorities for Alberta and western Canada are outlined. 相似文献
113.
Air pollution has become a serious problem in China as a result of that country's efforts in the last 30 years to become a great industrial power. The burning of coal, which currently provides over 70% of all China's energy needs, is a major source of air pollution. Because Chinese coal is high in sulfur and ash content and because most combustion devices in China have low efficiencies, SO2 and particulate emissions are a serious problem and are comparable to or exceed those found in many countries that are much more industrialized. Although most coal is burned in North China, acid precipitation is most severe in South China because of the lack of buffering loess dust found in the former region.The Chinese government has already taken major steps to mitigate air pollution, such as relocating polluting industries, supplying coal with lower sulfur content, using gas instead of coal for residential heating, and levying fines on industries that exceed pollution standards. Atmospheric environmental impact assessment (AEIA) is also required for all major new projects. This article describes three types of mathematical diffusion models and field and wind-tunnel experiments that are used in such assessments.The Chinese authorities believe that a range of technological, managerial, locational, and behavioral changes must be effected before the air of Chinese cities can be significantly improved. 相似文献
114.
The governments of British Columbia, Alberta, Saskatchewan, Manitoba, Northwest Territories, and Canada held joint consultations in 1980 to review the available information on acid rain from Western and Northern Canada. It was concluded that acid rain might become a problem in the future and, hence, a research, monitoring, and management strategy for acidic deposition was needed. An overview of the joint governments' management strategy, organization of research and monitoring programs, and accomplishments to date are discussed in this article.The authors are members of the Technical Committee for the Long Range Transport of Atmospheric Pollutants (LRTAP)/Acid Deposition in Western and Northern Canada, and represent Alberta and British Columbia, respectively. 相似文献
115.
116.
本文采集了重庆市三个污染轻重不同地区的雾水,并探讨了它们对体外PAM胞内ACP活性的影响。结果显示:污染严重的雾水对ACP活性呈现早期短暂抑制,中期明显激活,后期缓慢下降的峰形改变,在酶活性上升同时伴随酶染色区域在细胞内的扩散;污染轻的雾水仅有早期抑制作用而无刺激酶活性升高的表现。 相似文献
117.
中越边界—河口酸沉降的来源和发展趋势分析 总被引:4,自引:0,他引:4
河口当地无工业。燃料结构以柴禾为主,但80年代降水酸度PH值为3.80-5.12平均为4.4,频率高达100%。相距五年后,90年代进行三年连续监测,酸 雨PH值为3.82-6.90,平均为4.93,频率为97.6%。 相似文献
118.
119.
硝基苯测定方法的探讨 总被引:1,自引:0,他引:1
对硝基苯方法的测定,改为不加氢氧化钠和硫酸氢钾及用2.5%氨基磺酸代替2.5%氨基磺酸铵的两种方法与“还原←偶氮光度法”原分析方法作了分别的对比实验,实验结果经t值检验是一致的.并且改进后的方法精密度与准确度都很高. 相似文献
120.