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911.
912.
Paul J. Lioy Michael Avdenko Ronald Harkov Thomas Atherholt Joan M. Daisey 《Journal of the Air & Waste Management Association (1995)》2013,63(6):653-657
Abstract Many large metropolitan areas experience elevated concentrations of ground-level ozone pollution during the summertime “smog season”. Local environmental or health agencies often need to make daily air pollution forecasts for public advisories and for input into decisions regarding abatement measures and air quality management. Such forecasts are usually based on statistical relationships between weather conditions and ambient air pollution concentrations. Multivariate linear regression models have been widely used for this purpose, and well-specified regressions can provide reasonable results. However, pollution-weather relationships are typically complex and nonlinear—especially for ozone—properties that might be better captured by neural networks. This study investigates the potential for using neural networks to forecast ozone pollution, as compared to traditional regression models. Multiple regression models and neural networks are examined for a range of cities under different climate and ozone regimes, enabling a comparative study of the two approaches. Model comparison statistics indicate that neural network techniques are somewhat (but not dramatically) better than regression models for daily ozone prediction, and that all types of models are sensitive to different weather-ozone regimes and the role of persistence in aiding predictions. 相似文献
913.
J. S. Evans P. L. Kinney J. L. Koehler D. W. Cooper 《Journal of the Air & Waste Management Association (1995)》2013,63(5):551-553
Abstract There is a dearth of information on dust emissions from sources that are unique to the U.S. Department of Defense testing and training activities. However, accurate emissions factors are needed for these sources so that military installations can prepare accurate particulate matter (PM) emission inventories. One such source, coarse and fine PM (PM10 and PM2.5) emissions from artillery backblast testing on improved gun positions, was characterized at the Yuma Proving Ground near Yuma, AZ, in October 2005. Fugitive emissions are created by the shockwave from artillery pieces, which ejects dust from the surface on which the artillery is resting. Other contributions of PM can be attributed to the combustion of the propellants. For a 155–mm howitzer firing a range of propellant charges or zones, amounts of emitted PM10 ranged from ~19 g of PM10 per firing event for a zone 1 charge to 92 g of PM10 per firing event for a zone 5. The corresponding rates for PM2.5 were ~9 g of PM2.5 and 49 g of PM2.5 per firing. The average measured emission rates for PM10 and PM2.5 appear to scale with the zone charge value. The measurements show that the estimated annual contributions of PM10 (52.2 t) and PM2.5 (28.5 t) from artillery backblast are insignificant in the context of the 2002 U.S. Environment Protection Agency (EPA) PM emission inventory. Using national–level activity data for artillery fire, the most conservative estimate is that backblast would contribute the equivalent of 5 x 10–4% and 1.6 x 10–3% of the annual total PM10 and PM2.5 fugitive dust contributions, respectively, based on 2002 EPA inventory data. 相似文献
914.
J. Jacobson A. Kuja D. Shriner S. Perrigan P. Irving J. Lee 《Journal of the Air & Waste Management Association (1995)》2013,63(6):777-783
Radish plants were exposed three times per week to simulated acidic rain at pH values of 2.6 to 5.4 over the course of four weeks in trials performed at Argonne, Illinois; Ithaca and Upton, New York; Corvallis, Oregon; Oak Ridge, Tennessee; and Toronto, Canada. Uniform genotype, soil media and planting techniques, treatment procedures, biological measurements, and experimental design were employed. Growth of plants differed among trials as a result of variation in greenhouse environmental conditions according to location and facilities. Larger plants underwent greater absolute but lower relative reductions in biomass after exposure to the higher levels of acidity. A generalized Mitscherlich function was used to model the effects of acidity of simulated rain or dry mass of hypocotyls using data from three laboratories that performed duplicate trials. The remaining data, from three other laboratories that performed only one trial each, were used to test the model. When the laboratory by trial effect was removed (influence of different growth. conditions), lack of fit to the Mitscherlich function was insignificant. Thus, a single mathematical model satisfactorily characterized the relationship between acidity and mean plant response. The pH value associated with a 10 percent reduction in mass was 3.3 ± 0.3 for hypocotyls. No value was estimated for shoots because effects oh shoots were not significant. The results of this study demonstrate that a generalized exposure-response model can be developed in the presence of large variations in environmental conditions when plant culture and exposure to simulated rain are standardized among laboratories. 相似文献
915.
Robert J. Tidona Ahtisham A. Nizami Nicholas P. Cernansky 《Journal of the Air & Waste Management Association (1995)》2013,63(6):806-811
Experiments were carried out to determine the relative chemiluminescence quenching efficiencies as a function of third body concentration for each of the common combustion products, H2O, CO2, CO, H2, O2 and Ar. These results are compared with those of other investigators. The effect of reaction chamber pressure on analyzer response and the development of an analyzer design which incorporates an adjustable sample capillary inlet capable of maintaining a constant molar flow rate of sample gas to the reaction chamber are discussed. The effect of carbon monoxide interference on chemiluminescent NOx measurement has been isolated and found to be significant. A means of correcting NO, measurements for these CO interference effects is described. Quantification of NO and NO2 absorption in liquid water in NOx sampling systems has been made. Recommendations for sample system designs to handle the presence of water in the sample gas are made. 相似文献
916.
George R. Offen David Eskinazi Michael W. McElroy John S. Maulbetsch 《Journal of the Air & Waste Management Association (1995)》2013,63(7):864-871
From March 23rd to 26th, 1987, the city of New Orleans hosted 350 attendees, including representatives from 15 foreign countries, at the 1987 Joint Symposium on Stationary Combustion NOx Control. Cosponsored by the Electric Power Research Institute (EPRI) and the U.S. Environmental Protection Agency (EPA), the symposium provided attendees the opportunity to hear 49 papers in nine sessions covering technological and regulatory developments on NOx control in the United States and abroad since the May 1985 symposium in Boston. Session topics included general environmental issues, low-NOx combustion equipment (i.e., low-NOx burners, reburning, etc.), flue gas treatment, fundamental combustion research, and special issues for cyclone coal-fueled boilers, oil- and gas-fired boilers, and industrial combustion applications. Advances to the state-of-the-art presented at this symposium include: improved and/or newly applied combustion modifications for pulverized coal-fired boilers; further analyses of reburning, the leading combustion modification option for cyclone-equipped boilers; initial experiences with catalytic flue gas treatment in Europe; studies of NOx control retrofit options for oil- and gas-fired utility systems; and new technology developments for coal, oil, and gas fueled utility and industrial combustors. This paper summarizes those presentations that discussed significant changes since May 1985 in areas of potential interest to EPRI and its utility members. Where appropriate, they include our perspectives on the applicability of these newly disclosed findings to utility systems. 相似文献
917.
A Case Hisiory Michael R. Lake 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1397-1402
Regulations require that emissions of VOC from the application of can end sealing compounds be limited to 440 grams per liter. One can manufacturer has investigated the cost and feasibility of a VOC capture/control system and the availability and efficacy of water-based and high solids end sealing compounds. After characterizing and optimizing VOC evaporation rates, a prototype VOC containment system was tested on one can end sealing compound line. An 83 percent VOC capture efficiency was obtained at approximately 950 acfm. A cost analysis for a full facility capture and control system gave cost-effectiveness values of $1.21 to $2.36 per pound of VOC controlled. An evaluation oflow-VOC end sealing compounds, including long term pack tests, produced a water-based compound that could be implemented on pet food can ends by early 1986. Continuation of pack tests could allow full facility conversion to zero VOC water-based compounds by mid- to late-1987. Using an innovative averaging technique, the can manufacturer has achieved equivalent compliance with the 440 grams per liter standard. 相似文献
918.
T. Tirabassi M. Tagliazucca P. Zannetti 《Journal of the Air & Waste Management Association (1995)》2013,63(5):592-596
This paper presents a mixed methodology for the simulation of atmospheric disperson phenomena in which vertical diffusion is computed using an analytical solution of the K-theory equation, while horizontal diffusion is simulated by the Gaussian formula. This new formulation, while maintaining a simple analytical form for the concentration field, incorporates the effects of power-law vertical profiles of both wind speed and eddy diffusivity. The performance of this approach, which has been implemented into a full computer package (KAPPA-G), is evaluated by comparison with data from SF6 tracer experiments. 相似文献
919.
Elizabeth M. Fisher Catherine P. Koshland 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1384-1390
We have numerically modeled the breakdown of small quantities of several chlorinated hydrocarbons (CH3CI, CH2CI2, CHCI3, CCI4, C2H3CI, and C2H5CI) in a lean mixture of combustion products between 800 and 1480 K. This simulates the fate of poorly atomized waste in a liquid-Injection Incinerator. Kinetics calculations were performed using the CHEMKIN and SENKIN programs, with a reaction mechanism that was developed at Louisiana State University to model flat-flame burner experiments. A 99.99-percent destruction efficiency was attained In one second at temperatures ranging from 1280 to 960 K, with CCI4 requiring the highest temperature for destruction and C2H5CI the lowest. For all compounds except C2H5CI, there was a range of temperatures at which byproducts accounted for several percent of the elemental chlorine at the outlet. The more heavily chlorinated compounds formed more byproducts even though the amount of elemental chlorine was the same in all cases. The sensitivity of results to residence time, equivalence ratio, temperature profile, and the presence of additional chlorine, was examined for the case of CHCI3. 相似文献
920.
A. P. Altshuller 《Journal of the Air & Waste Management Association (1995)》2013,63(7):936-943
The observed ranges in nonmethane organic compound (NMOC) concentrations, NMOC composition and nitrogen oxides (NOX) concentrations have been evaluated for urban and nonurban areas at ground level and aloft of the contiguous United States. The ranges in NMOC to NOX ratios also are considered. The NMOC composition consistently shifts towards less reactive compounds, especially the alkanes, in air parcels over nonurban areas compared to the NMOC composition near ground level within urban areas. The values for the NMOC to NOX ratios, 1.2 to 4.2, in air aloft over nonurban areas are lower than in air at ground level urban sites, ≥8, and much lower than in air at ground level nonurban sites, ≥20. The layers of air aloft over a number of nonurban areas of the United States tend to accumulate NOX emissions from the tall stacks of large fossil fuel power plants located at nonurban sites. During the night into the morning hours, the air aloft is isolated from any fresh NMOC emissions predominately coming from near surface sources. Conversely, during this extended period of restricted vertical mixing, air near the surface accumulates NMOC emissions while this air is isolated from the major NOX sources emitting aloft. These differences in the distribution of NMOC and NOX sources appear to account for the much larger NMOC to NOX ratios reported near ground level compared to aloft over nonurban areas. Two types of experimental results are consistent with these conclusions: (1) observed increases in surface rural NOX concentrations during the morning hours during which the mixing depth increases to reach the altitude at which NOX from the stacks of fossil fuel power plants is being transported downwind; (2) high correlations of total nitrate at rural locations with Se, which is a tracer for coal-fired power plant NOX emissions. The implications of these conclusions from the standpoint of air quality strategies are suggested by use of appropriate scenarios applied to both urban and regional scale photochemical air quality models. The predictions from urban model scenarios with NMOC to NOX ratios up to 20 are that NOX control will result in the need for the control of more NMOC emissions than necessary in the absence of NOX control, in order to meet the O3 standard. On a regional scale, control of NOX emissions from fossil fuel power plants has little overall effect regionally but does result on a more local scale in both small decreases and increases in O3 concentrations compared to the baseline scenario without NOX control. The regional modeling results obtained to date suggest that NOX control may be effective in reducing O3 concentrations only for a very limited set of conditions in rural areas. 相似文献