Michael R. Ames

Al and Fe in PM 2.5 and PM 10 Suspended Particles in South-Central Florida: The Impact of the Long Range Transport of African Mineral Dust

Aluminum and iron were measured in daily samples collected at urban and rural sites near Ft. Myers, Florida, in 1995–1996 using a dichotomous sampler. Al and Fe concentrations were low during most of the year but they increased dramatically duringsummer when African dust was advected into Florida. The ratioof fine (less than 2.5 μm diameter) to coarse (2.5–10 μm) Al and Fe is relatively constant in African dust events with the fine accounting for a third to a half of the total. Also the mass ratio of Al-to-Fe is relatively constant at 1.8, a value similar to average crustal material. In contrast, in non-African dust the fine-to-coarse and Al-to-Fe ratios are extremely variable and generally much lower than those duringAfrican events when dust concentrations ranged up to 86 μg m-3. The timing and magnitude of the Ft. Myers dust peaks closely matched those measured concurrently in Miami, 200 km to the southeast. Large areas of the eastern United States are frequently impacted by African dust every summer. Although dustconcentrations can reach very high values it seems unlikely that African dust events alone will cause a violation of the Environmental Protection Agencys standards for PM 2.5 or PM 10. However, African dust in conjunction with emissions from local and regional sources could conceivably present a problemwith compliance. The probability of such an occurrence is heightened by the fact that dust concentrations are highest in the summer when pollution levels are often at a maximum in theeastern states.

Distribution of trace elements in selected pulverized coals as a function of particle size and density

Abstract Trace elements in coal have diverse modes of occurrence that will greatly influence their behavior in many coal utilization processes. Mode of occurrence is important in determining the partitioning during coal cleaning by conventional processes, the susceptibility to oxidation upon exposure to air, as well as the changes in physical properties upon heating. In this study, three complementary methods were used to determine the concentrations and chemical states of trace elements in pulverized samples of four US coals: Pittsburgh, Illinois No. 6, Elkhorn and Hazard, and Wyodak coals. Neutron Activation Analysis (NAA) was used to measure the absolute concentration of elements in the parent coals and in the size- and density-fractionated samples. Chemical leaching and X-ray absorption fine structure (XAFS) spectroscopy were used to provide information on the form of occurrence of an element in the parent coals. The composition differences between size-segregated coal samples of different density mainly reflect the large density difference between minerals, especially pyrite, and the organic portion of the coal. The heavy density fractions are therefore enriched in pyrite and the elements associated with pyrite, as also shown by the leaching and XAFS methods. Nearly all the As is associated with pyrite in the three bituminous coals studied. The sub-bituminous coal has a very low content of pyrite and arsenic; in this coal arsenic appears to be primarily organically associated. Selenium is mainly associated with pyrite in the bituminous coal samples. In two bituminous coal samples, zinc is mostly in the form of ZnS or associated with pyrite, whereas it appears to be associated with other minerals in the other two coals. Zinc is also the only trace element studied that is significantly more concentrated in the smaller (45 to 63 μm) coal particles.

Atmospheric mercury in the vapor phase, and in fine and coarse particulate matter at Perch River, New York

Daily samples of size segregated atmospheric particulate matter (da < 2.5 μm, and 2.5 μm < da < 10 μm), and vapor-phase mercury have been collected at five locations in upstate New York over a period of two years. Atmospheric concentrations were determined for mercury and, in the particulate matter, for up to 38 other elements by Instrumental Neutron Activation Analysis (INAA). At the Perch River sampling site, the average vapor-phase mercury concentration was 2.4 ng m−3 with a seasonal pattern of higher winter and lower summer concentrations observed over both years of sampling. The average fine and coarse particulate concentrations were 0.058 and 0.025 ng m−3, respectively. Concentrations for the particulate concentrations followed a log-normal frequency distribution with the most frequently occurring value for fine particulates being 0.012 ng m−3 and for coarse particulates 0.009 ng m−3. Episodic high concentrations of both fine and coarse particulate mercury indicate the impact of specific s ources. No correlation was found among the three different types of samples on either an overall or daily basis. By applying factor analysis (FA) to the data and using known marker species for specific types of emissions, the sources of the particulate mercury were identified and their contributions estimated. Fine particulate mercury concentrations were primarily associated with regional sources in the midwestern U.S.A., with copper smelting, and with the combined influence of aluminum and precious metals processing. Coarse particulate mercury concentrations were principally related to local aluminum processing facilities. The source identification results of the FA were confirmed by examining back-projected, mixed-layer wind trajectories. From February 1993 through the end of the particulate sampling in September 1993 fine particulate mercury concentrations declined significantly possibly due to the installation of particulate controls at one or more of the copper smelters.

Emissions of metals and polychlorinated dibenzo(p)dioxins and furans (PCDD/Fs) from Portland cement manufacturing plants: Inter-kiln variability and dependence on fuel-types

Emissions from Portland cement manufacturing facilities may increase health risks in nearby populations and are thus subject to stringent regulations. Direct testing of pollutant concentrations in exhaust gases provides the best basis for assessing the extent of these risks. However, these tests (i) are often conducted under stressed, rather than typical, operating conditions, (ii) may be limited in number and duration, and (iii) may be influenced by specific fuel-types and attributes of individual kilns. We report here on the results of more than 150 emissions-tests conducted of two kilns at a Portland cement manufacturing plant in Portugal. The tests measured various regulated metals and polychlorinated dibenzo(p)dioxins and furans (PCDD/Fs). Stack-gas concentrations of pollutants were found to be highly variable, with standard deviations on the order of mean values. Emission rates of many pollutants were higher when coal was used as the main kiln fuel (instead of petroleum coke). Use of various supplemental fuels, however, had little effect on stack emissions, and few statistically significant differences were observed when hazardous waste was included in the fuel mix. Significant differences in emissions for some pollutants were observed between the two kilns despite their similar designs and uses of similar fuels. All measured values were found to be within applicable regulatory limits.

Toxic substances from coal combustion -- A comprehensive assessment

The Clean Air Act Amendments of 1990 identify a number of hazardous air pollutants (HAPs) as candidates for regulation. Should regulations be imposed on HAP emissions from coal-fired power plants, a sound understanding of the fundamental principles controlling the formation and partitioning of toxic species during coal combustion will be needed. With support from the Federal Energy Technology Center (FETC), the Electric Power Research Institute, and VTT (Finland), Physical Sciences Inc. (PSI) has teamed with researchers from USGS, the Massachusetts Institute of Technology (MIT), the University of Arizona (UA), the University of Kentucky (UK), the University of Connecticut (UC), the University of Utah (W) and the University of North Dakota Energy and Environmental Research Center (EERC) to develop a broadly applicable emissions model useful to regulators and utility planners. The new Toxics Partitioning Engineering Model (ToPEM) will be applicable to all combustion conditions including new fuels and coal blends, low-NO{sub x} combustion systems, and new power generation plants. Development of ToPEM will be based on PSIs existing Engineering Model for Ash Formation (EMAF). This report covers the reporting period from the submission of the draft Phase 1 Final Report through the end of June, 1998. During this period two of the three Phase 2 coals were procured and pulverized samples were distributed to team members. Analysis of Phase 1 X-Ray Absorption Fine Structure (XAFS) data, particularly of mercury in sorbent samples, continued. An improved method for identifying mercury compounds on sorbents was developed, leading to a clearer understanding of forms of mercury in char and sorbents exposed to flue gas. Additional analysis of Phase 1 large scale combustion data was performed to investigate mechanistic information related to the fate of the radionuclides Cs, Th, and Co. Modeling work for this period was focused on building and testing a sub-model for vaporization of major elements during combustion.

Mechanical property and conductivity changes in several copper alloys after 13. 5 dpa neutron irradiation

A scoping experiment in which 25 different copper materials of 17 alloy compositions were irradiated to ≈13.5 dpa at ≈400°C in a fast reactor is described. The materials include rapidly solidified (RS) alloys, with and without oxide dispersion strengthening, as well as conventionally processed alloys. Immersion density, electrical conductivity, and yield stress and ductility by miniature disk bend testing have been measured before and after irradiation. In general, the RS alloys are stable under irradiation to 13.5 dpa, showing small conductivity changes and little or no swelling. Reduction of strength and ductility, in post-irradiation tests at the irradiation temperature, are not generally observed. Some conventionally processed alloys also performed well, although irradiation softening and swelling of several percent were observed in some cases, and pure copper swelled in excess of 5%. Higher dose irradiations will be required to establish the limits of swelling suppression in these alloys.

Progress in developing DBTT determinations from miniature disk bend tests

Experiments to investigate the possibility of obtaining ductile-to-brittle transition temperature (DBTT) data using bend tests of 3 mm diameter disks are described. A disk specimen 0.40 mm thick with two V-shaped grooves, 0.10 mm deep at right angles to each other along diameters of the disk face, is found to be suitable. In high strain-rate bend testing of materials which exhibit a Charpy V-notch (CVN) DBTT, such specimens undergo a marked change in load/deflection behavior as temperature is lowered. The temperature at which this transition occurs is 145–178 K below the CVN 68 J (50 ft-1b) temperature for three materials tested. There is some evidence that the miniature test transition correlates more consistently with the temperature at which CVN energy reaches a low value such as 7 J. This test offers interesting possibilities for in-service monitoring of critical components such as reactor pressure vessels. Further testing to investigate more fully the relationship between the miniature test and Charpy V-notch results is required.

Receptor Modeling for Elemental Source Contributions to Fine Aerosols in New York State

ABSTRACT Fine atmospheric particulate material was collected at five sites in upstate New York and analyzed for its trace element composition by instrumental neutron activation analysis. Of the 3700 daily samples collected over a 2-yr period, 1459 were analyzed for 39 elements, providing a large and detailed data set. Factor analysis (FA) was used to identify potential pollution sources or source regions and to construct inorganic source profiles for each. Following FA, the method of absolute factor scores-multiple linear regression was used to estimate the absolute elemental contribution of each of the identified sources. Factor analysis identified nine sources impacting the sampling region. Seven of these were found to be present in varying degrees among of the sampling sites. The other two sources had more localized impacts and were observed at only one of the sites each. Regional sources (such as the midwestern United States and eastern Canada) and crustal/ soil material accounted for the greatest amount of the trace elements measured in the collected material.

Microstructural evolution and swelling of high strength, high conductivity RS-PM copper alloys irradiated to 13.5 dpa with neutrons

Microstructures and swelling have been studied for a series of high-strength, high-conductivity rapidly solidified (RS) powder metallurgy (PM) alloys and oxide dispersion alloys which were neutron irradiated to 13.5 dpa at 400°C. Another article of these proceedings presents results for irradiation-induced changes in electrical conductivity, mechanical strength and ductility. The RS-PM alloys include Cu-Mg-Zr-Cr (MZC) and two oxide dispersion stabilized (ODS) alloys, Cu-Zr-ZrO 2 and Cu-Zr-Cr-ZrO 2 . Ingot materials and pure copper were also studied for comparison purposes. All alloys show no significant swelling after irradiation except OFHC pure copper, which exhibited 7.0% swelling. For the ODS alloys, TEM microstructures show stable fine oxide pinning of grain and subgrain boundaries as well as dislocations. In addition to fine oxides, a large amount of very fine metallic and intermetallic precipitation was observed within the grains.

Comments on: Using CALPUFF to evaluate the impacts of power plant emissions in Illinois: model sensitivity and implications

Levy et al. (2002) describe portions of their analysis ofthe public health impacts of emissions from nine powerplants in Illinois. This and similar analyses (Levy andSpengler, 2002; Freeman, 2001; Abt, 2000) use data-intensive models of air quality and health risks toestimate the number of deaths caused by increases inambient particulate matter (PM) concentrations due toemissions from specific sources. As modeled by Levyet al. (2002), 87% of the population-weighted, power-plant-derived PM