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991.
Hydrocarbon vapors associated with spilled petroleum products arouse regulatory concern and can pose a significant health and safety risk. While petroleum products do not contain a significant amount of methane (CH 4 ), high CH 4 contents in soil gas near petroleum spills have been reported. While CH 4 is nontoxic, its accumulation in shallow soil gas represents a potential explosion and asphyxiation hazard, especially in confined spaces. Identifying the source and origin of shallow CH 4 accumulations is an important part of evaluating potential exposure pathways, selecting appropriate remedial measures, and determining environmental liability. This paper discusses the potential nature and anthropogenic sources for shallow CH 4 and how integration of geological, geochemical, and land use data can be used to determine its origin and identify its source. Two case studies are presented, one where CH 4 associated with a gasoline spill is shown to be derived from a natural source rather than the gasoline, and a second where CH 4 associated with spilled crude oil is shown to be produced in the vadose zone by biodegradation of the oil. 相似文献
992.
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994.
Paul DeFalco Jr. 《Journal of the Air & Waste Management Association (1995)》2013,63(9):839-840
As a representative of EPA in the role of the Regional Administrator, I frequently feel like a middle man between the idealistic goals and timetables of the Congress and the practical problems of the states and local agencies in implementing air pollution control. As many of you know, EPA is one of the most decentralized of the federal agencies. Regional offices of EPA have much more authority to initiate action programs and allocate funds than do regional offices of HEW, HUD, or almost any other federal agency. This strong regional approach has sometimes been criticized as antithetical to a unified national approach to environmental policy. It has been said that you can’t run a national air program with ten idi-osyncracies. I disagree. I believe it is difficult or impossible to develop a program legislatively or administratively which is nationally uniform and yet recognizes the idiosyncracies of local situations and needs. 相似文献
995.
George T. Wolff Paul J. Lioy 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1034-1038
A stepwise multiple regression procedure was employed to develop the best .fit equation relating maximum afternoon ozone concentrations to meteorological and emission factors along a 24h upwind air parcel trajectory. The equation was developed using ozone data from receptor sites in Northern New Jersey and the resulting correlation coefficient was 0.96. The four most significant variables were the upwind ozone maximum on the previous day, today’s maximum temperature, the previous day’s upwind maximum temperature and the mean wind speed from the surface to 1000 m. The model was also successfully tested at 5 other sites in the Northeastern Quadrant of the United States. The results indicate that the model could be a potentially useful tool for air pollution forecasters in predicting maximum ozone concentrations in this quadrant of the country. 相似文献
996.
John R. Bush Paul L. Feldman Myron Robinson 《Journal of the Air & Waste Management Association (1995)》2013,63(4):365-371
This paper presents the results of work conducted by Research-Cottrell under EPA contract 68-02-2104. The feasibility of electrostatic precipitation at temperatures and pressures varying from ambient condition to 1366°K and 3550 kPa, respectively, has been demonstrated in a laboratory wire-pipe electrode system. Stable corona discharges are obtained at all temperatures subject to appropriate choices of electrode dimension, polarity, and pressure. Current-voltage characteristics are reported for dry air, a simulated combustion gas, and a substitute fuel gas. The effects of temperature, pressure, electrode geometry and polarity on sparkover voltage, corona-starting voltage, and current are evaluated. A precipitator performance model is included to incorporate this data into a high temperature, high pressure precipitator design. This model has been evaluated for an electrostatic (HTHP) precipitator following a pressurized fluidized bed combustor at 1089 K and 920 kPa. It is recommended that prototype HTHP electrostatic precipitators be applied to pilot coal gasifiers and fluidized bed combustors to obtain detailed design data and to verify the accuracy of the performance model under actual operating conditions. 相似文献
997.
Paul E. Rider Carole C. Rider Robert N. Corning 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1011-1013
One of the more common and useful methods of testing for SO2 in the atmosphere is to use the Huey sulfation plate.1 It has a layer of PbÕ2 particles suspended in an inert substrate which reacts with ambient SO2 gas to form PbSÛ4. The amount of PbSÛ4 can be determined by gravimetric, spec-trophotometric, or turbidimetric methods. The amount of atmospheric SO2 is estimated by assuming a linear correlation between it and measured PbS04 on the plate. 相似文献
998.
Anthony J. Buonicore Joseph P. Reynolds Louis Theodore Paul S. Farber 《Journal of the Air & Waste Management Association (1995)》2013,63(5):602-611
This paper presents a detailed review and critical evaluation of current technologies as applied to fine particulate emissions from coal-fired utility boilers. Quantitative assessments of the capabilities of both conventional and novel air pollution control devices to meet three different performance standards—the present New Source Performance Standard (NSPS) of 0.03 Ib particulate/MBtu heat input, and standards of 0.05 and 0.1 Ib particulate/MBtu are included. Each of the three conventional devices (electrostatic precipitator, fabric filter baghouse, and wet scrubber) is compared and rated with respect to eight different performance categories. This information can be used to determine the relative effectiveness and attractiveness of these three control devices. Novel devices are compared and rated in the same manner, the conclusions from which may provide the research administrator with a guide for the selection of those novel devices which offer the best potential for commercialization. The major conclusions of the investigation are: (1) The use of conventional scrubbers for fine particulate control on coal-fired utility boilers may no longer be feasible at the new NSPS of 0.03 Ib/MBtu. (2) At the old NSPS (0.1 Ib/MBtu) conventional electrostatic precipitators and baghouses were often competitive. For the new stricter standard, however, the baghouse generally is the more attractive alternative. (3) Novel devices appear to offer almost no hope for this particular application (at a commercial level) between now and 1985 and only little hope before 1990. 相似文献
999.
Paul D. Gutfreund Chung S. Liu Bruce R. Nicholson Edwin M. Roberts 《Journal of the Air & Waste Management Association (1995)》2013,63(9):864-871
The COMPLEX I and COMPLEX II Gaussian dispersion models for complex terrain applications have been made available by EPA. Various terrain treatment options under IOPT(25) can be selected for a particular application, one of which [IOPT(25) = 1] is an algorithm similar to that of the VALLEY model. A model performance evaluation exercise involving three of the available options with both COMPLEX models was carried out using SF6 tracer measurements taken during worst-case stable impaction conditions in complex terrain at the Harry Allen Plant site in southern Nevada. The models did not reproduce observed concentrations on an event by event basis, as correlation coefficients for 1-h concentrations of 0-0.3 were exhibited. When observed and calculated cumulative frequency distributions for 1-h and 3-h concentrations were compared, a close correspondence between observations and concentrations calculated with COMPLEX I, IOPT(25) = 2 or 3 was noted; both options consistently overestimated observed concentrations. With IOPT(25) = 1, upper percentile (maximum) values in the calculated frequency distribution exceeded the corresponding IOPT(25) = 2 or 3 value by roughly a factor of 2, and observed values by 2.5-5. COMPLEX II typically produced maximum values 2-4 times as great as COMPLEX I for the same terrain treatment option. From these results it is concluded that: 1) the physically unrealistic sector-spread approach used in VALLEY and COMPLEX I under stable impaction conditions is a surrogate for wind direction variation, and 2) the doubling of the plume centerline concentration due to ground reflection under terrain impingement conditions that is included in IOPT(25) = 1 is inappropriate. These findings were found to be consistent with an analysis of noncurrent observed and calculated SO2 χ/Q frequency distributions for 1, 3, and 24 hours near the Four Corners Plant in New Mexico. The comparison involved a four-year calculated χ/Q data set and a two-year observed χ/Q data set at the worst-case high terrain impact location near the plant. 相似文献