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811.
812.
Donald E. Seizinger Basil Dimitriades 《Journal of the Air & Waste Management Association (1995)》2013,63(1):47-51
Photochemical air pollution is known to be caused largely by automotive emissions such as hydrocarbons and oxygenated hydrocarbon derivatives. Unlike the hydrocarbons, the contribution of the oxygenates has been virtually unexplored, mainly because of lack of appropriate analytical methods. The objective of this study was to identify and estimate the levels of oxygenated hydrocarbon derivatives in exhaust from simple hydrocarbon fuels. This information is expected to yield ultimately estimates of the relative levels of various classes of oxygenates in exhaust from full-boiling-range gasolines. Identification and measurement of oxygenates in exhaust from the simplified fuels were accomplished using gas chromatography in conjunction with time-of-flight mass spectrometry. The analytical procedure involved concentration of the exhaust organics, followed by a two-stage chromatographic separation of the resultant mixture of oxygenates and hydrocarbons. Identified oxygenates in exhaust from nine test fuels included saturated and unsaturated aldehydes, ketones, and alcohols, as well as ethers, esters, and nitroalkanes; analytical data on organic acids were inconclusive. Of the identified noncarbonyl oxygenates, phenols, cyclic ethers and nitromethane appear to be relatively the most abundant. 相似文献
813.
Bruce Lighthart Victor E. Hiatt August T. Rossano Jr 《Journal of the Air & Waste Management Association (1995)》2013,63(10):639-642
Aerosols of Serratia marcescens ATCC 274 were suspended in a 709L rotating drum at 20 ± 1 °C and high to mid-range relative humidities. At specified times after bacterial aerosolization, sulfur dioxide was added to concentrations of 2.5, or 5 mg/m3. Viable cell decay rate constants, in control aerosols without added sulfur dioxide, increased rapidly from near 100% to 60% RH in the first hour (termed: young aerosol) of suspension, and from a minimum rate constant at 80% in the succeeding four hours (termed: old aerosol).Upon addition of sulfur dioxide to a cloud of S. marcescens, generally, viable cell decay rate constants increased further. One exception was at 80% relative humidity where maximum resistance to SO2 accelerated death was observed for old aerosols. Cells in young aerosols were particularly sensitive to SO2 addition at mid-range humidities, while in older aerosols the cells were insensitive to up to 5 mg SO2/m3 introduced at high RH; but were up to 10 times more sensitive than cells in young aerosols to a given increase (from 2.5 to 5 mg/m3) in SO2 concentration at mid-range humidities. 相似文献
814.
815.
R.E. George J.S. Nevitt J.A. Verssen 《Journal of the Air & Waste Management Association (1995)》2013,63(7):507-515
This paper is directed to those concerned with the air environment and its degradation by the burden of pollution from jet aircraft operations. A summary is presented of the results of a comprehensive air pollution study of jet aircraft operations at the Los Angeles International Airport (LAX). Included in the data obtained from this study are jet engine exhaust measurements for currently used turboprop, turbojet and turbofan engines; measurements of specific contaminants in the atmosphere inside and outside of passenger terminals and ticketing areas, and in aircraft cabins during ground operations including passenger loading and taxiing prior to takeoff; also presented are ambient air measurements in a two-mile radius of the airport. An evaluation is made of the emissions of contaminants from air transport operations and all related ground activities including motor vehicles, that contribute to the total atmospheric contaminant burden at the airport. 相似文献
816.
Thomas E. Kreichelt Thomas G. Keller 《Journal of the Air & Waste Management Association (1995)》2013,63(8):640-645
Studies of roof monitor emissions are conducted for two reasons: (1) to obtain design data necessary to engineer control systems to meet existing regulations, and (2) to determine projected control costs which can influence present day proposals for process change. Heated wire anemometers and rotating vane anemometers have been selected for velocity measurements, and high-volume air samplers have been selected to collect the particulate sample. Evaluation of other types of velocity sensing devices are described in the paper. Roof monitor studies must be preceded by a preliminary survey to allow the project engineer to determine the test sampling locations and specific methodology necessary for the given study, and to allow the engineer to determine the type of safety equipment, scaffolds, and power requirements necessary to complete the study. Field tests are conducted by operating a number of high-volume air samplers simultaneously while at the same time measuring the velocity of the gas through the monitor opening. Curves of particulate concentration and velocity as a function of monitor length are constructed. The concentration and velocity curves are then integrated together and the resultant curve is multiplied by the monitor width to determine a curve of mass emission rate as a function of monitor length. The total mass emission rate is represented by the area under the mass emission rate curve. Procedures for calibrating the anemometers and correcting for the effect of power fluctuation on the high-volume sampler operation are described. Data evaluation procedures and discussion of test error are also described. A study can cost between 10 and 20 thousand dollars, including the cost of manpower and the cost of scaffolds, power, cables, etc. It can take four months or more to conduct a study, from the preliminary survey phase through the report phase. 相似文献
817.
Ralph C. Sklarew Allan J. Fabrick Judith E. Prager 《Journal of the Air & Waste Management Association (1995)》2013,63(11):865-869
A new method for solving the turbulent atmospheric diffusion equation has been developed based on Lagrangian mass points, or particles moving through an Eulerian grid. The method is one of a family of Particle-/n-Cell techniques but is a unique extension to incorporate the effects of turbulent diffusion based on K-theory; thus the acronym PICK. In the three-dimensional computer-aided model, NEXUS (Numerical EXamination of Urban Smog), this method has been applied to simulation of carbon monoxide (CO) in Los Angeles. For CO the NEXUS simulation was within 20% of observed day-averaged concentrations at 12 stations and the hour-averages were also in good agreement. This model was extended to include the effects of photochemical smog in Los Angeles. The results of the photochemical simulation were also qualitatively correct due to rapid NO to NO2 conversion in the simulation. 相似文献
818.
D. V. Sandberg S. G. Pickford E. F. Darley 《Journal of the Air & Waste Management Association (1995)》2013,63(3):278-281
Pollutants sampled during the burning of 30 lb ponderosa pine fuel beds yielded emission factors for CO, hydrocarbon gases, and par-ticulate matter of 146, 8.4, and 9.1 lb/ton of fuel, respectively. When similar beds were treated with diammonium phosphate flame retardant, these factors increased to 166, 11.7, and 19.3 lb/ton of fuel, respectively. Gas chromatographic analysis of hydrocarbon gases showed that 15-40% of this material was composed of methane and eth-ylene. Ethane and acetylene were the next most abundant materials, with photochemically important materials constituting minor portions of this gaseous component. Fuel beds treated with flame retardant produced more oiefins, and this production lasted throughout the smoldering phase of burning. These tests showed that the smoldering phase of combustion is of major importance to air pollutant production during slash burning. The initial 80% of the fuel burned accounted for only 20-30% of HC and CO emissions. This suggests that a rapid mop-up of slash burns could substantially reduce air pollutant production. 相似文献
819.
M. E. Smith T. T. Frankenberg 《Journal of the Air & Waste Management Association (1995)》2013,63(6):595-601
A study of the “before” and “after” ground-level S02 concentrations near the Muskingum River Plant of the American Electric Power System shows that the conversion from low to high stacks has accomplished marked reductions in ambient concentrations. These reductions are in reasonable agreement with theoretical calculations and are most apparent within 5 km of the source. EPA Standards are now being met in this area despite the presence of the 1440 MW power plant burning 5% sulfur fuel with no treatment of the stack gas. 相似文献
820.
J. M. Genco H. S. Rosenberg M. Y. Anastas E. C. Rosar J. M. Dulin 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1244-1253
This paper describes some technical and economic aspects of the nahcolite ore injection process for the simultaneous removal of fly ash and sulfur oxides from stack gases. The process is capable of removing greater than 99% of the particulate matter and greater than 70% of the sulfur oxides present in such gases. In the process, nahcolite ore, a naturally occurring material containing 70 to 90% sodium bicarbonate, is ground to 90% passing through —200 mesh screens. Approximately 20% of the ground ore is used to precoat the filter bags in a baghouse filter while the remainder of the material is fed into the flue gas Just ahead of the baghouse. The flue gas is drawn through the baghouse by induced draft fans and sent up the stack. Most of the SO2 and practically all of the fly ash in the flue gas can be removed as the gas passes through the filter bags. The spent nahcolite ore and fly ash are collected and conveyed to waste disposal as landfill, or alternatively processed for insolubilization by coprecipitation prior to landfilling. The technical feasibility of the process has been demonstrated in both bench scale and pilot scale engineering studies. Economic analyses performed for the cases of plants located in the midwest and southwest indicate lower capital costs for the nahcolite injection process when compared to wet scrubbing. On an annual cost basis, the nahcolite ore Injection process is comparable in cost to wet scrubbing for the case of the southwestern power plant, and somewhat more expensive for the case of the midwestern plant. 相似文献