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41.
A survey of academic programs in air pollution control was made. Results from the 127 schools reporting are tabulated by state. Faculty involved in air pollution instruction are identified. Some conclusions and recommendations are presented.  相似文献   
42.
The principle of fabric filtration has only recently been accepted for fossil fuel fired boiler particulate emissions control. Information on design criteria is, therefore, limited. The paper provides data on the few installations where baghouses have been installed and successfully operated. The general conclusion is that a strong relationship exists between air to cloth ratio and bag life.  相似文献   
43.
This study was undertaken to identify seasonal and source effects on the par-ticulate contaminants of the New York City atmosphere and ultimately to relate the concentrations of these contaminants to the tissue concentrations in residents of New York City. Continual weekly samples of particulates have been collected at three stations in the New York area on 8 by 10 in. glass fiber filters at a flow rate of 20 cfm.

The sample is ashed with a Tracerlab Low Temperature Asher and leached with nitric acid. Metals analyzed by the Atomic Absorption method include Pb, V, Cd, Cr, Cu, Mn, Ni, and Zn. Lead-210, total particulate, and benzene and acetone soluble organic material are also determined.

The data have been related to various meteorological parameters over a one year period to define significant seasonal and source influences, as well as site to site variations. Very significant inverse correlations to temperature are obtained for suspended particulates, vanadium, and nickel at both Manhattan and Bronx sites. Particulates show a less significant inverse correlation to temperature In lower Manhattan. Oil-fired space heating sources appear to account for as much as 50% of the particulates in the Bronx at the peak demand period.

Lead, copper, and cadmium show a general inverse correlation to average wind speed, and a direct correlation to temperature. The latter is most likely due to an inverse relation between wind speed and temperature. The heating season input for particulates, vanadium, and nickel is so great as to overcome most of the dilution effect due to winds. The other elements having more constant nonseasonal inputs, definitely reflect the effects of the wind.

The most significant site effect occurs with cadmium, which has a concentration in lower Manhattan three times that of the Bronx over a period of six to seven months in the summer and fall. The differences observed for cadmium and particulates may be explained by emission source factors which have not as yet been studied.  相似文献   
44.
The particle and gas properties that profoundly affect design and performance of fly ash precipitators are discussed and evaluated in this section. Relation of the coal burned to these properties and to the precipitator gas cleaning problem is broadly examined. The need for a high order of technology consistently applied to cope successfully with the wide and often uncertain variations in coal and ash properties encountered in precipitation practices is emphasized.  相似文献   
45.
Typical air quality effect levels of photochemical oxidants on specific plant substrates are illustrated. These include ambient oxidant exposure data measured as “total oxidant” as well as laboratory exposures to individual pure oxidants, ozone, or PAN compounds, since these oxidants are identified in photochemical smog. New terms, “PaNs” and “PAN-type” oxidant, have been proffered for purposes of clarification of the terminology. PAN-type oxidant more precisely defines the phytotoxicant complex causing silvering or bronzing of the lower leaf surfaces in lieu of the older term “oxidant.” Due to the recognition of several oxidizing phytotoxicants in recent years, it is recommended that the term oxidant be reserved for use as a generic term. A tabular classification of the oxidizing phytotoxicants found in community photochemical smog and the specific syndromes produced is provided.  相似文献   
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47.
Geodiversity—the variability of Earth's surface materials, forms, and physical processes—is an integral part of nature and crucial for sustaining ecosystems and their services. It provides the substrates, landform mosaics, and dynamic physical processes for habitat development and maintenance. By determining the heterogeneity of the physical environment in conjunction with climate interactions, geodiversity has a crucial influence on biodiversity across a wide range of scales. From a literature review, we identified the diverse values of geodiversity; examined examples of the dependencies of biodiversity on geodiversity at a site‐specific scale (for geosites <1 km2 in area); and evaluated various human‐induced threats to geosites and geodiversity. We found that geosites are important to biodiversity because they often support rare or unique biota adapted to distinctive environmental conditions or create a diversity of microenvironments that enhance species richness. Conservation of geodiversity in the face of a range of threats is critical both for effective management of nature's stage and for its own particular values. This requires approaches to nature conservation that integrate climate, biodiversity, and geodiversity at all spatial scales.  相似文献   
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49.
The efficacy of ozonation and of photocatalysis processing in the treatment of pulp mill ECF (elementary chlorine free) bleaching and textile effluents was evaluated by determining total organic carbon reduction (TOC) and the toxicity. The chronic toxicity of the effluents was evaluated by the ability to inhibit the growth of algae Selenastrum capricornutum. Cultured hamster V79 fibroblasts were used to assess the cytotoxicity of effluents submitted to different detoxification processes. Two endpoints were measured in V79 cells: 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) reduction and neutral red uptake (NRU). Both treatment processes were able to reduce the TOC, although ozonization was less effective for pulp mill ECF bleaching. The pulp mill ECF bleaching and textile effluents reduced the growth of S. capricornutum by 39% and 27%, respectively. However, at the highest concentration tested, the textile effluents treated by photochemical process for 60 min showed increased cytotoxicity in V79 cells compared to the untreated effluent when assessed by the NRU and MTT reduction assays (increases of 30% and 40%, respectively). Pulp mill ECF bleaching effluent treated by ozonization had a similar cytotoxicity to that of untreated effluent in the NRU assay. In contrast, the MTT reduction assay indicated that effluents treated with ozone were around 20% more cytotoxic than untreated effluents. These results show that cultured fibroblasts may be useful for studying cellular responses to pollutants and may be included in tests to monitor the efficiency of effluent detoxification processes.  相似文献   
50.
Environmental Science and Pollution Research - Heat stress is one of the main obstacles to achieving efficient cattle production systems, and it may have numerous adverse effects on cattle. As the...  相似文献   
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