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本文概述了柴油机尾气中PAHs的分析方法,着重论述了采样及预处理方法,特别对预处理方法进行了深入的探讨。另外,通过对柴油机两种不同工况下产生的尾气进行分析后发现,柴油机转速越高,其排放尾气中PAHs的含量就越低。 相似文献
154.
Although the process of documenting compliance with NEPA (the National Environmental Policy Act) requires no drastic revisions, it can be managed more rigorously. Suggestions for revision can be grouped under five major steps: 1) getting a complete proposal from the applicant; 2) getting the decision-making process onto the right decision-making path; 3) modifying the applicant's proposal 4) going down a shorter path through the EA/FONSI (environmental assessment and finding of no significant impact) or through categorical exclusion review; and 5) going down the longer path through the EIS. Step 2 is perhaps the most critical, because there a decision must be made whether to write an EA/FONSI or an EIS, on the basis of whether the proposal would “significantly affect … the … environment.” In the past, this decision has not always been made promptly or rigorously. Accordingly, we suggest that the agency responsible for NEPA compliance should develop a system (a “black box”), consisting of a core group of specialists working with an interdisciplinary team, using sophisticated techniques for modeling impacts and directing both their research and their writing according to the concept of significance. By determining more efficiently and reliably whether the impacts of a proposal would be significant, such an approach would improve management of the total process. 相似文献
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硫酸盐化速率反映大气中二氧化硫及硫的化合物的污染状况,文章通过对银川市1999~2003年硫酸盐化速率的346个监测数据的统计分析,研究了煤烟型城市环境空气中二氧化硫的变化规律及污染状况。 相似文献
156.
Rice WE 《Environmental monitoring and assessment》2004,99(1-3):251-257
A sub-surface desert water harvester was constructed in the sagebrush steppe habitat of south-central Idaho, U.S.A. The desert
water harvester utilizes a buried micro-catchment and three buried storage tanks to augment water for wildlife during the
dry season. In this region, mean annual precipitation (MAP) ranges between about 150–250 mm (6″–10″), 70% of which falls during
the cold season, November to May. Mid-summer through early autumn, June through October, is the dry portion of the year. During
this period, the sub-surface water harvester provides supplemental water for wildlife for 30–90 days, depending upon the precipitation
that year. The desert water harvester is constructed with commonly available, “over the counter” materials. The micro-catchment
is made of a square-shaped, 20 mL. “PERMALON” polyethylene pond liner (approximately 22.9 m × 22.9 m = 523 m2) buried at a depth of about 60 cm. A PVC pipe connects the harvester with two storage tanks and a drinking trough. The total
capacity of the water harvester is about 4777 L (1262 U.S. gallons) which includes three underground storage tanks, a trough
and pipes. The drinking trough is refined with an access ramp for birds and small animals. The technology is simple, cheap,
and durable and can be adapted to other uses, e.g. drip irrigation, short-term water for small livestock, poultry farming
etc. The desert water harvester can be used to concentrate and collect water from precipitation and run-off in semi-arid and
arid regions. Water harvested in such a relatively small area will not impact the ground water table but it should help to
grow small areas of crops or vegetables to aid villagers in self-sufficiency. 相似文献
157.
对城市生活垃圾的分类回收、处理进行了探讨,对完善城市基础设施建设,改善投资环境将起到重要作用。 相似文献
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Nahanni National Park Reserve is located at southwestern NWT-Yukon border. One of the first UNESCO World Heritage sites, Nahanni lies within Taiga Cordillera and Taiga Shield Ecozones. Base and precious metal mining occurred upstream of Nahanni prior to park establishment. Nahanni waters, sediments, fish, and caribou have naturally elevated metals levels. Baseline water, sediment and fish tissue quality data were collected and analyzed throughout Nahanni during 1988–91 and 1992–97. These two programs characterized how aquatic quality variables are naturally varying in space and time, affected by geology, stream flow, seasonality, and extreme meteorological and geological events. Possible anthropogenic causes of aquatic quality change were examined. Measured values were compared to existing Guidelines and site-specific objectives were established. 相似文献