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261.
R. A. Stoehr J. P. Pezze 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1119-1122
The evolution of H2S and SO2 from hot blast furnace slags by reaction with H2O has been found to be dependent upon the presence of O2 or H2 in the reaction zone as well as on the temperature. H2 has been found to produce a small increase in H2S and a small decrease in SO2 emission, while O2 has been found to produce a very great inhibiting effect on H2S emission and only a small increase in SO2 emission. The total emission of sulfur bearing gases is much less when H2O + air is blown at the slag than when H2O + Ar is blown at the slag, particularly at 1200°C and above. These effects may be useful in attempts to design systems for slag quenching which will produce less pollution. 相似文献
262.
Joseph D. McCain John P. Gooch Wallace B. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(2):117-121
This paper presents results of source size distribution measurements over the size range from 0.1 μm to 5 μm for six classes of particulate sources and fractional efficiency measurements on five full scale electrostatic precipitators and one pilot scale precipitator. The precipitators all showed moderately high to high particulate collection efficiencies for particles having diameters larger than a few micrometers or smaller than a few hundredths of a micrometer and a minimum in collection efficiency for particles having diameters of a few tenths of a micrometer. 相似文献
263.
264.
Brian P. Leaderer Theodore R. Holford Jan A. J. Stolwijk 《Journal of the Air & Waste Management Association (1995)》2013,63(2):154-157
A PM10 monitoring network was established throughout the South Coast Air Basin (SOCAB) in the greater Los Angeles region during the calendar year 1986. Annual average PM10 mass concentrations within the Los Angeles metropolitan area ranged from 47.0 µg m-3 along the coast to 87.4 µg m-3 at Rubldoux, the furthest inland monitoring station. Measurements made at San Nicolas Island suggest that regional background aerosol contributes between 28 to 44 percent of the PM10 aerosol at monitoring sites In the SOCAB over the long term average. Five major aerosol components (carbonaceous material, NO- 3, SO= 4, NH+ 4, and soil-related material) account for greater than 80 percent of the annual average PM10 mass at all on-land monitoring stations. Peak 24-h average mass concentrations of nearly 300 µg m-3 were observed at inland locations, with lower peak values (?130–150 µg m-3) measured along the coast. Peak-day aerosol composition was characterized by increased NO- 3 Ion and associated ammonium ion levels, as compared to the annual average. There appears to be only a weak dependence of PM10 mass concentration on season of the year. This lack of a pronounced seasonal dependence results from the complex and contradictory seasonal variations in the major chemical components (carbonaceous material, nitrate, sulfate, ammonium ion and crustal material). At most sites within the Los Angeles metropolitan area, PM10 mass concentrations exceeded both the annual and 24-h average federal and state of California PM10 regulatory standards. 相似文献
265.
Louis Theodore Joseph P. Reynolds 《Journal of the Air & Waste Management Association (1995)》2013,63(7):777-779
This paper is directed to those individuals involved in design of electrostatic precipitators. The Deutsch-Anderson model is usually employed by industry for the design of electrostatic precipitators. The so-called process design variable in this approach is the total capture area in the precipitator. Unfortunately, little is available on the equipment design of this unit, i.e., the geometric arrangement of the plates that constitute the capture area and the external dimensions of the physical structure that houses the precipitator components. These are important economic considerations, and it is to this subject that this paper is directed. It is relatively easy to predict equipment costs for “off-the-shelf” electrostatic precipitators; it is more difficult to closely predict the cost for a custom-made unit, which is more often the case encountered in practice. Once the capture area is calculated, the total precipitator cost becomes a strong function of the outer casing and outer accessories of the physical system. In this paper, a model is presented that can help minimize precipitator cost. An illustrative example complements the development of the model. 相似文献
266.
G. P. Greiner D. A. Furlong D. W. VanOsdell L. S. Hovis 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1125-1130
The concept of electrostatic stimulation of fabric filtration (ESFF) has been investigated at pilot scale. The pilot unit consisted of a conventional baghouse in parallel with an ESFF baghouse, allowing direct comparison. All results reported in this paper are for pulse-cleaned bags in which the electric field was maintained parallel to the fabric surface. The performance of the ESFF baghouse has been superior to the parallel conventional baghouse by several measures. The ESFF baghouse demonstrated: (1) a reduced rate of pressure drop increase during a filtration cycle, (2) lower residual pressure drop, (3) stable operation at higher face velocities, and (4) improved particle removal efficiency. These benefits can be obtained with only minor modifications to conventional pulse-jet hardware and at low electrical power consumption. The indicated ability to operate at increased face velocities with only modest expenditure for electrical hardware leads to very favorable economic projections. 相似文献
267.
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
268.
Lawrence P. Hanrahan Henry A. Anderson Kay A. Dally Ann D. Eckmann Marty S. Kanarek 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1164-1167
Mobile homes utilize a class of prefabricate construction techniques which rely greatly upon the use of particle board and hardwood plywood paneling for structural components. This has resulted In household sources which may emit formaldehyde into the home, since urea-formaldehyde resins are used as the bonding agent in most pressed wood stocks. A series of 137 mobile home households was investigated to determine indoor formaldehyde exposure concentrations. Homes were selected based on the estimated age of the construction components. Homes were studied serially for a nine-month period, with formaldehyde samples obtained on a monthly basis using a modified NIOSH chromotropic acid procedure. Formaldehyde concentrations were found to range from less than 0.10 ppm to 2.84 ppm. The median exposure concentration was 0.39 ppm. Analysis of variance was performed on each home to discern visit and room measurement effects. Eighty-nine percent of the homes exhibited no measurement placement effects, while only 10 percent failed to demonstrate between-visit variance effects. Regression models were constructed to predict household formaldehyde concentrations. Concentrations exhibited an inverse relationship with the age of the construction materials. A weighted least squares regression model of log of home age predicting temperature-corrected log formaldehyde explained 82 percent of the formaldehyde variation. 相似文献
269.
Amado LL Rosa CE Castro MR Votto AP Santos LC Marins LF Trindade GS Fraga DS Damé RC Barros DM Geracitano LA Bianchini A de la Torre FR Monserrat JM 《Chemosphere》2011,82(11):1563-1570
This study analyzed water quality in regions around Patos lagoon (Southern Brazil) that are under anthropogenic pressure. Water samples were collected from five different sites, including one used as a source for human consumption (COR) and others known to be influenced by human activities (IP). Danio rerio (Teleostei, Cyprinidae) organisms were exposed for 24 h to these water samples, plus a control group. It was observed that: (1) reactive oxygen species levels were lower in COR and IP than in the control group; (2) glutamate-cysteine ligase (catalytic subunit) expression was higher in COR than in other sites; (3) exposure to all water samples affected long-term memory (LTM) when compared to control group. Thus, some water samples possess the ability to modulate the antioxidant system and to induce a decline in cognitive functions, as measured by LTM. The obtained results indicate that a combination of variables of different organization level (molecular, biochemical and behavioral) can be employed to analyze water quality in impacted regions. 相似文献
270.
Polycyclic aromatic hydrocarbons (PAHs) adsorbed on cigarette sidestream smoke particulates (CSSPs) have been regarded as important contributors to lung carcinogenesis in never smokers. However, limited information is available on PAH levels in cigarette sidestream smoke. Here we determine the concentrations of 22 PAHs, including 16 US EPA priority PAHs, in CSSPs generated from a high market-share domestic brand in Taiwan. Five of the 22 PAHs are undetectable. The remaining 17 PAHs constitute about 0.022% of the total mass of CSSPs. Near one fifth of the PAH mass come from IARC group 1 and group 2 carcinogens. Carcinogenic potency is equivalent to 144 ng benzo[a]pyrene per cigarette converted according to potency equivalency factors (PEFs). The CSSP condensate could activate AhR activity and induce AhR target gene expression. High concentrations of CSSPs also exhibited AhR-independent cytotoxicity. However, mixing the 17 PAHs as the composition in the CSSP condensate could not reconstitute either capacity. Since AhR activation and cytotoxicity are important mechanisms underlying carcinogenic potency, the results suggest that other component compounds play a more active role in carcinogenesis. The approach of individual PAH profiling plus PEF conversion commonly used in risk assessment is likely to underestimate the risk caused by environmental cigarette smoke exposure. 相似文献