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901.
Frank P. Scaringelli Raymond E. Boone George A. Jutze 《Journal of the Air & Waste Management Association (1995)》2013,63(6):310-313
A method is described for dynamic calibration of an acid aerosol analyzer based on a commercial modification of the Thomas Autometer and manufactured by the Instrument Development Company. This automated instrument removes acid aerosol from an air stream by sonic impaction, and the sulfuric acid collected is determined conductometrically. An all-glass aerosol generator based on the reaction of water vapor with sulfur trioxide vapor released from fuming sulfuric acid was built for the calibration. Air samples were withdrawn for instrument calibration before and after the concentration of the acid aerosol was determined by titration. The apparent particle size as determined by an Andersen sampler ranged from 2.0 microns to less than 0.68 micron and exhibited a sharp peak with mass median diameter at 1.3 microns in the distribution curve. The size of the aerosol, within certain limits, could be controlled by humidity. Data indicated a linear response with an aerosol collection efficiency of 80 percent in the important respirable size range. 相似文献
902.
903.
Harry J. Ettinger George W. Royer 《Journal of the Air & Waste Management Association (1995)》2013,63(2):108-111
Considerable interest is currently directed toward atmospheric visibility and its relationship to particle size and mass concentration. Previous work has been limited to heavily polluted urban areas, and visibility studies have not included particle size characterization. An air sampling program was carried out in a nonurban, low pollution area to relate: (a) total particulate mass concentration measured with a high-volume sampler, (b) particulate mass size distribution measured with aerodynamic size selective samplers, and (c) visual range measured by the integrating nephelometer. For low suspended particulate mass concentrations, the following relationship was defined between visual range (Lv) and mass concentration (M ? μg/m3): 相似文献
904.
Jack M. Leavîtt Lawrence A. George Robert E. Clark 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1133-1140
TVA is conducting a program of intermittent control of SO2 emissions at nine of its coal-fired power plants.The program is designed to limit SO2 emissions by reducing generation during adverse atmospheric conditions to avoid exceeding ambient SO2 standards. Each is identified as a Class I or Class II program—based primarily on its design and operational complexity. The four Class I programs (Paradise, Cumberland, Allen, Gallatin) operate 7 days/week from early morning through mid-afternoon. The five Class II programs (Kingston, Widows Creek, Colbert, Johnsonville, Shawnee) operate 24 hours/day and 7 days/week. Environmental data stations (EDS) are located at each plant site; the staff has the responsibility for the collection and validation of the onsite meteorological data, the SO2 mobile and fixed monitoring network data, the plant operational data, and the meteorological forecast data from the Meteorological Forecast Center in Muscle Shoals, AL. At the EDS, the data are entered into a computer operating model for scheduling plant generation reductions. 相似文献
905.
John Salop George F. Maier 《Journal of the Air & Waste Management Association (1995)》2013,63(6):641-642
ABSTRACT The Las Vegas Valley PM10 Study was conducted during 1995 to determine the contributions to PM10 aerosol from fugitive dust, motor vehicle exhaust, residential wood combustion, and secondary aerosol sources. Twenty-four-hr PM10 samples were collected at two neighborhood-scale sites every sixth day for 13 months. Five week-long intensive studies were conducted over a middle-scale sub-region at 29 locations that contained many construction projects emitting fugitive dust. The study found that the zone of influence around individual emitters was less than 1 km. Most of the sampling sites in residential and commercial areas yielded equivalent PM10 concentrations in the neighborhood region, even though they were more distant from each other than they were from the nearby construction sources. Based on chemical mass balance (CMB) receptor modeling, fugitive dust accounted for 80–90% of the PM10, and motor vehicle exhaust accounted for 3–9% of the PM10 in the Las Vegas Valley. 相似文献
906.
George Su Kathryn A. Wurzel 《Journal of the Air & Waste Management Association (1995)》2013,63(2):160-162
The information presented in this paper is concerned with the effects of ambient ozone on crop yield reduction and the resultant economic losses. Yield data for nine crops within the South Coast Air Basin (SCAB) of California were obtained for the 12-year period, 1964 through 1975. Ozone concentrations, temperature, precipitation, and relative humidity data were related to the yields by using regression models. Estimated yield reductions due to ozone for 1975, varied from zero to 57% depending on crop and location. Economic welfare losses calculated from the yield reductions were $57.3 and $45.7 million for producer’s and consumer’s surplus, respectively. The total loss from ozone to agriculture related economic sectors determined by input-output analysis was $276 million in the SCAB and $36.6 million in the remainder of the state. 相似文献
907.
Haluk Ozkaynak Arthur D. Schatz George D. Thurston Ronald G. Isaacs Rudolf B. Husar 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1176-1185
Epidemiological assessments of population exposures to airborne particles are often hampered by the scarcity of available fine particle mass measurements. In an attempt to overcome this serious problem, we analyze In this paper methods for predicting fine particle (M 1) and Inhalable particle (IP) mass concentrations using relative humidity corrected light extinction coefficient (b ext) estimated from airport visual range (V r) observations. The analyses presented are based on theoretical determinations as well as statistical investigations utilizing EPA's NASN and Inhalable Particle Monitoring Network (IPMN) data bases and routine airport visual range observations In twelve large U.S. cities. Our results Indicate that, after controlling for certain limitations of airport visual range data, most of the regression models developed in this paper can be applied satisfactorily to predict M t and IP. Furthermore, our findings Indicate that a more representative formula than the commonly used meteorological range formula to predict atmospheric b ext values in urban areas may be b ext = (1.8 ± 0.04)/V r. Because of known local or regional influences, however, we do suggest calibration of any predictive model which utilizes airport visibility data against site-specific aerometric data on particle mass concentrations or scattering coefficient measurements. 相似文献
908.
Nelson A. Kelly Martin A. Ferman George T. Wolff 《Journal of the Air & Waste Management Association (1995)》2013,63(2):150-158
This analysis represents the first characterization of the photochemistry and transport of ozone in the Detroit metropolitan area and provides a basis for comparing data for Detroit to that for other cities. The characterization is based on a comprehensive set of meteorological and chemical measurements obtained at a site in the urban core of Detroit during the summer of 1981, together with measurements of O3, nitrogen oxides (NO X ), and nonmethane organic compounds (NMOC) from rural, suburban, and urban areas in southeastern Michigan and adjacent areas of Ontario. For the quartile (23 days) with highest ozone maxima (97-180 ppb), the maxima occurred 10-70 km north-northeast of the city on days that were warm and hazy with light southsouthwest winds. On such days there was a marked accumulation of ozone precursors (NMOC and NOX) in the early morning, as well as a rapid chemical removal of NO X (NO X half-life of ~5 h) from morning to midday. The timing of the daily ozone increase across the study region suggests that local photochemical generation in a moving plume was responsible for more than half of the ozone measured downwind. However, there was also evidence that ozone transported into Detroit as part of the regional background was a significant part of the O3 maxima on high ozone days. The average contributions of photochemistry and transport for the 23 days with the highest ozone maxima were estimated to be 57 ppb and 47 ppb, respectively. 相似文献
909.
George T. Wolff Nelson A. Kelly Martin A. Ferman Martin S. Ruthkosky David P. Stroup Patricia E. Korsog 《Journal of the Air & Waste Management Association (1995)》2013,63(5):585-591
During August, 1982 and January and February, 1983, General Motors Research Laboratories operated air monitoring sites on the Atlantic Coast near Lewes, Delaware and 1250 km to the east on the southwest coast of Bermuda. The overall purpose of this project was to study the transformations of the principal acid precipitation precursors, NO x and SO x species, as they transport under conditions not complicated by emissions from local sources. In this paper, the measurements of gas and particulate species from Lewes are described and the composition and sources of sulfate aerosol, which is the most important haze-producing species, are investigated. On the average, the total suspended particulate (TSP) concentration was 27.9 μg/m3 while the PM10 (mass of particles with a diameter less than or equal to 10 μm) concentration was 22.0 μg/m3 or 79 percent of the TSP. The PM10 consisted of 6.1 μg/m3 of coarse particles (CPM, diameter = 2.5 ? 10μm) and 15.9 μg/m3 of fine particles (FPM, diameter < 2.5 μm). On a mass basis the most important constituents of the fine particulate fraction were sulfate compounds, 50 percent, and organic compounds, 30 percent. The mean light extinction coefficient corresponds to a visual range of 18-20 km. Most of the extinction can be attributed to the sulfate (60 percent) and organic carbon (13 percent). Particle size measurements show that the mass median aerodynamic diameter for both species is 0.43 μm. This is a typical size for a hydrated sulfate aerosol. For carbon, however, this is a larger size than previously reported and results in a more efficient light scattering aerosol. Principal component analyses indicate that coal combustion emissions from the midwestern U.S. are the most significant source of sulfate in Lewes during the summer and winter. 相似文献
910.