William J. Trompetter

Air particulate matter pollution in Ulaanbaatar, Mongolia: determination of composition, source contributions and source locations

Ulaanbaatar, the capital city of Mongolia is subject to high air particulate matter pollution episodes during winter and during dust storm events in spring and autumn that have severe implications for the health of the exposed population. This paper presents the results of fine (PM2.5) and coarse (PM10–2.5) particulate matter monitoring in Ulaanbaatar from 2004 to 2008 and receptor modelling to determine the sources contributing to particulate matter pollution. Ion Beam Analysis was used to determine elemental concentrations in the two size fractions and black carbon was measured with a light reflectance device. Mass contributions to ambient particle concentrations from emission sources were estimated by positive matrix factorisation and air mass back–trajectory analysis was used to assess probable source locations. The results show that crustal matter sources are the primary contributors to the coarse particle fraction. Combustion sources (coal combustion, biomass burning, and motor vehicles) dominate the fine fraction of particulate matter in the Ulaanbaatar airshed, primarily from local emission sources but forest fires to the north can be a significant contributor to biomass burning concentrations at times. Analysis of seasonal differences showed that coal combustion processes were largely responsible for fine particle air pollution episodes during winter. Temporal trends show an increase in the coal combustion contributions over the monitoring period. We suggest that this is linked to the increase in the Ulaanbaatar population and a consequent increase in the use of coal for power generation and domestic heating purposes.

Identification of Particulate Matter Sources on an Hourly Time-Scale in a Wood Burning Community

Particulate matter (PM) sources at two different sites in a rural town in New Zealand were investigated on an hourly time-scale. Streaker samplers were used to collect hourly, size-segregated PM(10-2.5) and PM(2.5) samples that were analyzed for elemental content using ion beam analysis techniques. Black carbon concentrations were determined using light reflection and PM(10) concentrations were recorded using colocated continuous PM monitors. PM(10) concentrations at both sites displayed a diurnal pattern, with hourly PM(10) concentration maxima in the evening (7 pm-midnight) and in the morning (7-9 am). One of the monitoring sites experienced consistently higher average PM(10) concentrations during every hour and analysis indicated that katabatic flows across the urban area contributed to the increased concentrations observed. Source apportionment using positive matrix factorization on the hourly data revealed four primary PM(10) sources for each site: biomass burning, motor vehicles, marine aerosol and crustal matter. Biomass burning was the most dominant source at both sites and was responsible for both the evening and morning PM(10) concentration peaks. The use of elemental speciation combined with PM(10) concentrations for source apportionment on an hourly time-scale has never been reported and provides unique and useful information on PM sources for air quality management.

AIR PARTICULATE RESEARCH CAPABILITY AT THE NEW ZEALAND ION BEAM ANALYSIS FACILITY USING PIXE AND IBA TECHNIQUES

PIXE and Ion Beam Analysis are one of the few techniques that can be used to identify the elemental composition of air particulates without destroying the filter sample. They are key tools for identifying the sources and determining the relative contribution of biogenic and anthropogenic sources of air particulate matter pollution in our environment. Over the last 8 years, specialised equipment has been designed and built at the New Zealand Ion Beam Analysis facility in Lower Hutt for semi automated analysis of air filters. The equipment and experimental techniques have been refined to improve sensitivities for many of the elements in the periodic table. At GNS, sensitivities have recently been further improved by using two X-ray detectors simultaneously with different amounts of X-ray filtering and collimation. The average limit of detection is improved from 66 ng/cm2 (typical for a setup using a single detector) to 35 ng/cm2 using two detectors simultaneously. The New Zealand Ion Beam Analysis facility now routinely analyses air particulate matter collected on filters from several locations around New Zealand. In this paper, results of air particulate studies from several locations in the Wellington region are presented.

Role of oxides in high velocity thermal spray coatings

Abstract Thermal spray coatings applied with high velocity techniques such as high velocity air fuel (HVAF), produce coatings with superior quality in comparison to other traditional techniques such as plasma spraying. To date, our knowledge of the bonding processes and the structure of the particles within thermal spray coatings is very subjective. To improve our understanding of these materials, especially of the surface oxide layer, Ni80/Cr20 HVAF thermally sprayed coatings were studied with scanning electron microscope, nuclear reaction analysis (NRA) and X-ray photoelectron spectroscopy (XPS). In particular, NRA and XPS were used to characterise the oxide composition that gives the coatings their excellent oxidation resistance. The surface oxide on the Ni80/Cr20 particles was found to be only 7 nm thick and enriched in SiO 2 . A surprising finding was that the composition of the Ni80/Cr20 powder remained unchanged during the coating process despite the high velocity application with the HVAF method.

Evidence of mechanical interlocking of NiCr particles thermally sprayed onto Al substrates

Ni-chrome alloy particles were thermally sprayed onto aluminum substrates using the high-velocity air fuel technique. The particle substrate interface was investigated with focused ion beam microscopy, cross-sectional scanning electron microscopy, and cross-sectional transmission electron microscopy. No evidence of melting or chemical bonding was found in the samples. Instead, evidence of mechanical bonding was found that had been predicted by a previous theoretical study by Grujicic et al. At locations where the particle and substrate are in intimate contact, the interface exhibited interlocking features. These features are caused by the effects of turbulence due to interfacial instability and mixing at the interface during the coating process, resulting in a strong particle-substrate bond. Conversely, separated interfaces exhibited smooth surfaces, suggesting insignificant bonding between the particle and the substrate. The discovery of these interfacial formations, together with no evidence of chemical bonding across the particle-substrate interface indicate that mechanical interlocking is the dominant bonding mechanism.

Composition and source contributions of air particulate matter pollution in a New Zealand suburban town

Wainuiomata, a suburban town located at the southern end of the North Island of New Zealand, is subject to air particulate matter pollution episodes during the winter. The results of fine (PM2.5) and coarse (PM2.5–10) particulate matter monitoring in Wainuiomata from July 2006–September 2008 are presented. Receptor modeling was used to determine the sources contributing to particulate matter pollution and mass contributions to ambient particle concentrations from emission sources were estimated. PM10 concentrations displayed a seasonal pattern, with peak concentrations occurring during the winter. The results demonstrate that marine aerosol and crustal matter sources were the primary contributors to the coarse particle fraction, while the fine particle fraction was dominated by biomass burning with smaller contributions from marine aerosol and secondary sulfate particles. Arsenic was found to be present in the fine particle fraction and was associated with biomass burning, suggesting the use of copper chrome arsenate treated timber for domestic heating. Analysis of seasonal differences revealed that biomass burning was largely responsible for fine particle pollution episodes during the winter. Marine aerosol featured significantly as a PM10 source all year due to New Zealand’s remote oceanic location.

LITHIUM AND BORON DISTRIBUTIONS IN GEOLOGICAL SAMPLES

Abstract The concentration of elements in whole rocks and maps of their distribution in petrographic thin sections were determined using ion beam microprobe analysis. Lithium and B contents in rocks and minerals are measured using the 7Li(p,α)4He and 11B(p,α)8Be reactions. X-rays are simultaneously detected for elements heavier than Na, including Cl, to corroborate microscopic mineral identification. The ion beam analysis data are integrated with observations under the petrographic and scanning electron microscopes, as well as analysis using X-ray fluorescence and the electron microprobe. Lithium, B and Cl can be used to assess volcanic and hydrothermal processes. In a study of 62 samples, Li, B and Cl increase proportionally with increasing silica content in fresh volcanic rocks from the Taupo Volcanic Zone in New Zealand. The median values for Li, B and Cl in rhyolites (SiO2%=70–76%) are 35, 20 and 800 ppm (wt), respectively, and 19, 11 and 340 ppm (wt), respectively, for andesites (SiO2=56–62%). Boron and Cl preferentially partition into the glassy matrix of rhyolite and andesite. In rhyolites, Li occurs mainly in minerals such as hornblende and biotite but resides in the glassy matrix of andesites. During hydrothermal alteration of volcanic rocks, Cl always partitions into hydrothermal solutions while Li and B are preferentially redistributed in the rock. As hydrothermal alteration proceeds, Cl in the rock decreases and B and Li increase proportionally, depending on the type of mineralization present and the temperature of alteration.

High time-resolved elemental components in fine and coarse particles in the Pearl River Delta region of Southern China: Dynamic variations and effects of meteorology.

Hourly-resolved PM2.5 and PM10-2.5 samples were collected in the industrial city Foshan in the Pearl River Delta region, China. The samples were subsequently analyzed for elemental components and black carbon (BC). A key purpose of the study was to understand the composition of particulate matter (PM) at high-time resolution in a polluted urban atmosphere to identify key components contributing to extreme PM concentration events and examine the diurnal chemical concentration patterns for air quality management purposes. It was found that BC and S concentrations dominated in the fine mode, while elements with mostly crustal and oceanic origins such as Si, Ca, Al and Cl were found in the coarse size fraction. Most of the elements showed strong diurnal variations. S did not show clear diurnal variations, suggesting regional rather than local origin. Based on empirical orthogonal functions (EOF) method, 3 forcing factors were identified contributing to the extreme events of PM2.5 and selected elements, i.e., urban direct emissions, wet deposition and a combination of coarse mode sources. Conditional probability functions (CPF) were performed using wind profiles and elemental concentrations. The CPF results showed that BC and elemental Cl, K, Fe, Cu and Zn in the fine mode were mostly from the northwest, indicating that industrial emissions and combustion were the main sources. For elements in the coarse mode, Si, Al, K, Ca, Fe and Ti showed similar patterns, suggesting same sources such as local soil dust/construction activities. Coarse elemental Cl was mostly from the south and southeast, implying the influence of marine aerosol sources. For other trace elements, we found vanadium (V) in fine PM was mainly from the sources located to the southeast of the measuring site. Combined with CPF results of S and V in fine PM, we concluded shipping emissions were likely an important elemental emission source.

Sources of particulate matter pollution in a small New Zealand city

Abstract The sources of PM10 in the Tahunanui airshed of Nelson, New Zealand were investigated using positive matrix factorization (PMF) on elemental data obtained from filters collected from September 2008-September 2009. Also, the source(s) of peak, non-winter PM10 concentrations that exceeded the National Environmental Standard for PM10 were investigated using PM10 and meteorological data from 2007–2012 and the PMF results. Seven PM10 sources were identified: biomass burning, motor vehicles, secondary sulfate, marine aerosol, crustal matter, protective coating activities and fertilizer. Overall, biomass burning was the dominant source contributor (35% of PM10). Analyses of PM10 concentration dependences on meteorological variables showed that peak, non-winter PM10 concentrations that occurred under moderate-to-high wind speeds from the southwest were the result of vehicular movements on unsealed roads in an industrial area. From this information, it is possible for Nelson City Council, who manages air quality at Tahunanui, to formulate mitigation strategies to reduce the impact of biomass burning and industrial vehicles on local air quality.

AIR PARTICULATE MATTER POLLUTION IN ULAANBAATAR CITY, MONGOLIA

Due to increased energy demands from its rapidly growing economy and population, ambient air in Ulaanbaatar, the capital city of Mongolia contains some of the highest reported air particulate matter (APM) concentrations in the world. The purpose of this study is to identify major APM sources. Source apportionment is an elegant and effective way to establish baseline data for mitigation strategies that focus on reducing APM pollution. The Nuclear Research Centre at the National University of Mongolia has been conducting APM pollution studies in Ulaanbaatar since 2004. Results presented here are based on a sampling campaign from June 2008 to May 2009 at two sites in Ulaanbaatar. APM samples were collected on polycarbonate filter, in two size fractions, fine (PM2.5) and coarse (PM10-2.5) particulate matter. Ion beam analysis provided the elemental concentration values and receptor modeling was used to determine the sources contributing to the particulate matter pollution. The results show that the main sources of PM pollution are soil, motor vehicles, coal and wood combustion, with varying contributing amounts at each site. Source contributions to PM2.5 at a residential site were found to be: soil 47%, coal combustion 35%, motor vehicles/road dust 13% and biomass burning 4%. At the residential site it was found that the primary source contributors to PM10-2.5 were soil 71%, coal combustion 10%, and motor vehicles/road dust 19%.Source contributions to PM2.5 at a non-residential site were found to be: coal combustion 92%, motor vehicles/road dust 3%, soil 3% and biomass burning 2%. At the non-residential site it was found that the primary source contributors to PM10-2.5 were: soil 92%, motor vehicle/road dust 5% and coal combustion 3%.