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221.
S. Behrooz Ghorishi Charles B. Sedman 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1191-1198
ABSTRACT The capture of elemental mercury (Hg0) and mercuric chloride (HgCl2) by three types of calcium (Ca)-based sor-bents was examined in this bench-scale study under conditions prevalent in coal-fired utilities. Ca-based sorbent performances were compared with that of an activated carbon. Hg0 capture of about 40% (nearly half that of the activated carbon) was achieved by two of the Ca-based sorbents. The presence of sulfur dioxide (SO2) in the simulated coal combustion flue gas enhanced the Hg0 capture from about 10 to 40%. Increasing the temperature in the range of 65-100 °C also caused an increase in the Hg0 capture by the two Ca-based sorbents. Mercuric chloride (HgCl2) capture exhibited a totally different pattern. The presence of SO2 inhibited the HgCl2 capture by Ca-based sorbents from about 25 to less than 10%. Increasing the temperature in the studied range also caused a decrease in HgCl2 capture. Upon further pilot-scale confirmations, the results obtained in this bench-scale study can be used to design and manufacture more cost-effective mercury sorbents to replace conventional sorbents already in use in mercury control. 相似文献
222.
Charles H. Darvin Lyndon S. Cox Daryl Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(3):339-344
ABSTRACT During recent years, greater emphasis has been placed on the control of particulate emissions from painting operations. This has gained more importance as more is learned about the potential release of toxic metals to the atmosphere from painting operations. This has led to queries about the efficiency of various painting arrestor systems to reduce particulate discharges to the atmosphere. Even more important is the capability of the arrestor systems to control PM10 emissions. In 1995, the U.S. Environmental Protection Agency initiated a study to evaluate various dry paint overspray arrestor systems. This study was designed to evaluate not only the total emissions control capability of the arrestor but also the PM10 control capability of the various system designs. Paint overspray arrestor systems using five different filtration concepts or materials were selected. They include systems constructed of fiberglass, paper, Styrofoam, and cardboard materials. These systems used filtration techniques incorporating the following filtration phenomena and designs: cyclone, baffle, bag systems, and mesh systems. The testing used an optical particle counting procedure to determine the concentration of particles of a given size fraction to penetrate a test arrestor system. The results of the testing indicated that there are significant differences in the efficiency of the tested system designs to capture and retain PM10. This paper summarizes the results of the research conducted to determine the capability of the arrestor systems to capture particulate of sizes down to approximately 1 μm in surface diameter. 相似文献
223.
Rufus Edwards Kirk R. Smith Brent Kirby Tracy Allen Charles D. Litton Susanne Hering 《Journal of the Air & Waste Management Association (1995)》2013,63(6):789-799
Abstract In developing countries, high levels of particle pollution from the use of coal and biomass fuels for household cooking and heating are a major cause of ill health and premature mortality. The cost and complexity of existing monitoring equipment, combined with the need to sample many locations, make routine quantification of household particle pollution levels difficult. Recent advances in technology, however, have enabled the development of a small, portable, data-logging particle monitor modified from commercial smoke alarm technology that can meet the needs of surveys in the developing world at reasonable cost. Laboratory comparisons of a prototype particle monitor developed at the University of California at Berkeley (UCB) with gravi-metric filters, a tapered element oscillating microbalance, and a TSI DustTrak to quantify the UCB particle monitor response as a function of both concentration and particle size and to examine sensor response in relation to changes in temperature, relative humidity, and elevation are presented here. UCB particle monitors showed good linearity in response to different concentrations of laboratory-generated oleic acid aerosols with a coarse (mass median diameter, 2.1 µm) and fine (mass median diameter, 0.27–0.42 µm) size distributions (average r2 = 0.997 ± 0.005). The photoelectric and ionization chamber showed a wide range of responses based on particle size and, thus, require calibration with the aerosol of interest. The ionization chamber was five times more sensitive to fine rather than coarse particles, whereas the photoelectric chamber was five times more sensitive to coarse than fine. The ratio of the response between the two sensors has the potential for mass calibration of individual data points based on estimated parameters of the size distribution. The results demonstrate the significant potential of this monitor, which will facilitate the evaluation of interventions (improved fuels, stoves, and ventilation) on indoor air pollution levels and research on the impacts of indoor particle levels on health in developing countries. 相似文献
224.
Ray E. Carter Jr. Dennis D. Lane Glen A. Marotz Charles T. Chaffin Tim L. Marshall Melissa Tucker 《Journal of the Air & Waste Management Association (1995)》2013,63(4):480-488
A method of predicting point and path-averaged ambient air VOC concentrations is described. This method was developed for the case of a plume generated from a single point source, and is based on the relationship between wind directional frequency and concentration. One-minute means of wind direction and wind speed were used as inputs to a Gaussian dispersion model to develop this relationship. Both FTIR spectrometry and a whole-air sampling method were used to monitor VOC plumes during simulated field tests. One test set was also conducted using only whole-air samplers deployed in a closely-spaced network, thus providing an evaluation of the prediction technique free of any bias that might exist between the two analytical methods. Correlations between observed point concentrations and wind directional frequencies were significant at the 0.05 level in most cases. Predicted path-integrated concentrations, based on observed point concentrations and meteorological data, were strongly correlated with observed values. Predicted point concentrations, based on observed path-integrated concentrations and meteorological data, accurately reflected the location and magnitude of the highest concentrations from each test, as well as the shape of the concentration-versus-crosswind distance curve. 相似文献
225.
Charles J. Weschler Helen C. Shields Datta V. Naik 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1562-1568
Indoor and outdoor ozone concentrations were measured from late May through October at three office buildings with very different ventilation rates. The indoor values closely tracked the outdoor values, and, depending on the ventilation rate, were 20 to 80 percent of those outdoors. The Indoor/outdoor data are adequately described with a mass balance model. The model can also be coupled with reported air exchange rates to estimate indoor/outdoor ratios for other structures. The results from this and previous studies indicate that Indoor concentrations are frequently a significant fraction of outdoor values. These observations, and the fact that most people spend greater than 90 percent of their time indoors, indicate that indoor ozone exposure (concentration × time) is greater than outdoor exposure for many people. Relatively Inexpensive strategies exist to reduce indoor ozone levels, and these could be implemented to reduce the public’s total ozone exposure. 相似文献
226.
Howard M. Ellis Peter C. Liu Charles Runyon 《Journal of the Air & Waste Management Association (1995)》2013,63(6):670-675
The purpose of this study was to evaluate alternative prediction models for the SO2 concentrations produced in the vicinity of the Ohio Edison Company Sammis Power Plant. The plant is situated in the northeastern portion of the Ohio River Valley in complex terrain. Comparisons of the 16 highest predicted and measured short-term SO2 concentrations were conducted for a one year period for 58 alternative models. Several models were found to predict reasonably accurately the 16 highest measured 24-hour SO2 concentrations. Each of these models requires an upward adjustment in the plume centerline location as the plume is transported downwind in rising terrain. These same models overpredict by substantial margins the 16 highest measured 3-hour SO2 concentrations. Improvements in emissions inventory data and improvements in the prediction models used are believed necessary to increase prediction accuracy further. 相似文献
227.
Charles W. Lewis Robert K. Stevens Reinhold A. Rasmussen Carlos A. Cardelino Thomas E. Pierce 《Journal of the Air & Waste Management Association (1995)》2013,63(3):299-300
ABSTRACT Previously reported volatile organic compounds (VOC) radiocarbon (14C) measurements for 1992 summertime Atlanta, GA, have been compared with chromatographic data and emissions inventory predictions. The chromatographic approach that was used provided a more comprehensive VOC characterization than typically achieved, and the emissions inventory was research-grade level (date-, site-, and time-specific). The comparisons are in general agreement that biogenic emissions contribute only modestly (<10%) to the VOC content of the particular ambient samples that were collected and measured. The choices of sampling site (near city-center) and times (early morning and late evening) are major influences on the results, which consequently should not be regarded as representing the average VOC biogenic impact for the Atlanta area. 相似文献
228.
Charles J. Weschler Stephen P. Kelty Joyce E. Lingousky 《Journal of the Air & Waste Management Association (1995)》2013,63(6):624-629
As part of an energy conservation program recently implemented by the Bell System, fans in many telephone equipment buildings now operate only when necessary to bring the temperature within allowable limits, rather than continuously. In the study reported here the effects of fan operation on indoor-outdoor dust relationships were monitored at 2 representative telephone offices. Automatic dichotomous samplers were used to collect fine and coarse aerosol particles inside telephone equipment buildings at Wichita, KS and Lubbock, TX. At both sites, outdoor samples (roof top) were collected at the same time as the indoor samples. During the tests the building fans were repetitively cycled between 2-week intervals of continuous fan operation and 2-week intervals of intermittent fan operation. The indoor dust concentrations typically increased when the fans were off. The results indicate that this increase was due to loss of constant filtration, but not due to loss of building pressurlzation (i.e., filtration of the recirculated air is largely responsible for the lower dust levels when the fans are running continuously). An expression is derived for the relative dust increase when the building fans are switched off. Among other factors, the relative increase is directly proportional to the efficiency of the building filters and to the rate at which air is recirculated through them. The present findings can be extended to similar buildings. 相似文献
229.
André Bélanger Charles Vincent Domingos de Oliveira 《Journal of environmental science and health. Part. B》2013,48(5):615-625
Abstract In 1986 strawberry plots were treated with dimethoate, malathion, permethrin and cypermethrin at 80% bloom of primary flowers. In 1987 the plots were sprayed with dimethoate, malathion and permethrin at 30% bloom. Residue analysis of these insecticides on the flowers were analyzed using solvent extraction and gas liquid chromatography. Residue analysis at 0 to 18 days on flowers and fruit showed an exponential decrease. Organophosphates tended to degrade more quickly than synthetic pyrethroids. The results are discussed in the context of an integrated pest management program. 相似文献
230.
Service has received increasing attention in the management literature, yet sustainability of service is often overlooked. In this Incubator we examine the potential for client involvement through shared and self‐leadership to foster empathy enhanced service and reduced costs, both of which may support a more sustainable service delivery process. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献