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981.
982.
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
983.
David L. Peterson Michael J. Arbaugh 《Journal of the Air & Waste Management Association (1995)》2013,63(7):921-927
Growth of ponderosa pines with visible symptoms of ozone injury was compared with that of asymptomatic trees in the southern Sierra Nevada, California. Time series analysis indicated that there was no significant reduction in annual radial increment of symptomatic trees during recent years compared to past growth and growth of asymptomatic trees. First order autocorrelation and climatic variables accounted for a large proportion of the variance in growth index, and winter precipitation was positively correlated with growth for all size and age classes. Although ozone concentrations are high enough to cause chlorosis and premature needle senescence in ponderosa pine, there has been no significant change in growth associated with ozone injury. 相似文献
984.
Gregory W. Traynor Michael G. Apte Andrew R. Carruthers James F. Dillworth Richard J. Prill David T. Grimsrud 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1011-1015
Many energy conservation strategies for residences involve reducing house air exchange rates. Reducing the air exchange rate of a house can cause an increase in pollutant levels if there is an indoor pollution source and if the indoor pollutant source strength remains constant. However, if the indoor pollutant source strength can also be reduced, then it is possible to maintain or even improve indoor air quality. Increasing the insulation level of a house is a means of achieving energy conservation goals and, in addition, can reduce the need for space heating and thereby reduce the pollutant source strengths of combustion space heaters such as unvented kerosene space heaters, unvented gas space heaters, and wood stoves. In this paper, the indoor air quality trade-off between reduced infiltration and increased insulation in residences is investigated for combustion space heaters. Two similar residences were used for the experiment. One residence was used as a control and the other residence had infiltration and insulation levels modified. An unvented propane space heater was used as the source in this study. A model was developed to describe the dependence of both indoor air pollution levels and the appliance source strengths on house air exchange rates and house insulation levels. Model parameters were estimated by applying regression techniques to the data. Results show that indoor air pollution levels in houses with indoor combustion space heating pollution sources can be held constant (or lowered) by reducing the thermal conductance by an amount proportional to (or greater than) the reduction of the air exchange rate. 相似文献
985.
Robert R. Arnts Robert L. Seila Joseph J. Bufalini 《Journal of the Air & Waste Management Association (1995)》2013,63(4):453-460
A relative rate procedure was used to measure hydroxyl rate constants at room temperature in the presence of oxygen. The photolysis of methyl nitrite in the presence of nitric oxide was used to generate OH radicals. The rate of loss of the test compounds was measured relative to that of ethane (kOH = 2.74 × 10-13 cm3 molec-1 s-1). The rates obtained at 297 ± 2 K are: acetylene = (7.8 ± 1.6) × 10-13 cm3 molec-1 s-1,1,2-dichloroethane (2.8 ± Q.6) × 10-13 cm3 molec-1 s-1, 1,2-dibromoethane (2.4 ± 0.5) × 10-13 cm3 molec-1 s-1, p-dichlorobenzene (4.3 ± 0.9) × 10-13 cm3 molec-1 s-1 and carbon disulfide (29 ± 6) × 10-13 cm3 molec-1 s-1. Under a proposed EPA rule, this OH rate determination procedure could be used to determine if a given volatile organic will be subject to control for reduction of photochemical ozone. 相似文献
986.
J.D. Hamilton K.H. Reinert J.V. Hagan W.V. Lord 《Journal of the Air & Waste Management Association (1995)》2013,63(4):247-251
Abstract Synthetic polymers reach municipal landfills as components of products such as waste household paints, packaging films, storage containers, carpet fibers, and absorbent sanitary products. Some polymers in consumer products that reach landfills are designed to photodegrade or biodegrade. This article examines the significance of degradable polymers in management of solid waste in municipal landfills. Most landfills are not designed to photodegrade or biodegrade solid waste. Landfill disposal of stable polymers such as polyacrylics and polyethylenes is not associated with significant polymer degradation or mobility. Stability to photodegradation and biodegradation is an advantage when municipal landfills are used for disposal of polymer products as solid waste. Use of landfill disposal can be a responsible means to manage polymer waste and can be part of an overall waste management plan which includes source reduction, recycling, reuse, composting, and waste-to-energy incineration. 相似文献
987.
David A. Wampler Shelly Miller-Leiden William W. Nazaroff Ashok J. Gadgil Andres Litvak K.R.R. Mahanama 《Journal of the Air & Waste Management Association (1995)》2013,63(6):494-500
Abstract Most environmental tobacco smoke (ETS) issues from the tips of smoldering cigarettes between puffs. Smokeless ashtrays are designed to reduce ETS exposure by removing particulate and/or gas-phase contaminants from this plume. This paper describes an experimental investigation of the effectiveness of four smokeless ashtrays: two commercial devices and two prototypes constructed by the authors. In the basic experimental protocol, one or more cigarettes was permitted to smolder in a room. Particulate or gas-phase pollutant concentrations were measured in the room air over time. Device effectiveness was determined by comparing pollutant concentrations with the device in use to those obtained with no control device. A lung deposition model was applied to further interpret device effectiveness for particle removal. The commercial ashtrays were found to be substantially ineffective in removing ETS particles because of the use of low-quality filter media and/or the failure to draw the smoke through the filter. A prototype ashtray using HEPA filter material achieved better than 90% particle removal efficiency. Gasphase pollutant removal was tested for only one prototype smokeless ashtray, which employed filters containing activated carbon and activated alumina. Removal efficiencies for the 18 gas-phase compounds measured (above the detection limit) were in the range of 70 to 95%. 相似文献
988.
Robert C. Pegnam Michael J. Pilat 《Journal of the Air & Waste Management Association (1995)》2013,63(3):303-308
Particulate mass concentration, particle size distribution, and particle chemical composition measurements have been conducted on the gases exhausting from a chromic acid anodizing process tank. Particle mass concentrations in the 200 to 20,000 μg/m3 range were measured using open-faced filters (47 mm diameter) adjacent to the process tank liquid and with closed filters (90 mm diameter) in the exhaust duct. Particle size distributions, measured using University of Washington Mark 3 and Mark 20 Cascade Impactors, showed the particle aerodynamic mass median diameter was about 3 microns. Chemical analysis of the particle samples obtained by the Modified EPA Method 5 sampling train, the Mark 20 UW Cascade Impactors, and by the 47 mm and 90 mm diameter filters showed Cr+6 concentrations in the 20 to 1,500 μg/m3 range with over 99 percent of the chromium in particles larger than 1.0 microns diameter. An integrating nephelometer was used to measure the light scattering coefficient of the exhaust gases upstream of the wet scrubber. The light scattering coefficient increased by a factor of about 2–3 over the background level during the 40 minute time period while a part was being anodized. The bscat values ranged from 3 × 10?5 to 3 × 10?4 meters?1 for the aerosol particles less than about 6 microns aerodynamic diameter. 相似文献
989.
Alan M. Wolsky Edward J. Daniels Bassam J. Jody 《Journal of the Air & Waste Management Association (1995)》2013,63(4):449-454
This paper summarizes the results of research conducted at Ar-gonne National Laboratory (ANL) to develop and design a novel method for the recovery of CO2 from flue gases. The basic process concept Involves the combustion of a hydrocarbon fuel using a mixture of oxygen and carbon dioxide (or CO2 and H20) rather than air as the oxidant, which results In a product stream that contains primarily CO2 and H2O. This stream Is then dried and conditioned to meet the specifications of the end user, A slip stream of CO2 (or CO2, and H20) is used as a diluent in the combustion chamberto maintain a flame temperature equivalent to the temperature that would otherwise be obtained using air as an oxidant. The cost-effectiveness of the process in recovering C02 is dependent on the scale of the operation, the type of fuel used, the cost of oxygen, and the cost of capital. The sensitivity of the cost of the recovered C02 to these variables Is discussed, and a model for estimating the cost of CO2 recovered using the ANL process Is presented. 相似文献
990.
Nigel J. Tapper Aidan W. Sudbury 《Journal of the Air & Waste Management Association (1995)》2013,63(4):433-441
Odor is acknowledged as a major community air pollution nuisance, but the problems of analysis, particularly in Identifying the origin of odor, are also well recognised. One approach to the problem has been the development of computational schemes which use wind directions at the times of odor observations to locate the likely source of odor. An earlier technique, PONG, has now been superseded by a more sophisticated version, PONG2, which incorporates Gaussian plume modeling techniques. This paper describes the operation of PONG2 in the odor source mapping mode and provides an analysis of the Insensitivity of the technique to errors in input. Then, using specific Australian examples of community odor nuisance emanating from a large sewage treatment complex near Melbourne, and an irrigated golf course within metropolitan Darwin, the paper outlines the utility of PONG2 in resolving problem odor sources at a range of scales and levels of complexity. 相似文献