Journal of the Air & Waste Management Association, 2006
This study tested the feasibility of using pyrolysis (Py)-gas chromatography (GC)/mass spectromet... more This study tested the feasibility of using pyrolysis (Py)-gas chromatography (GC)/mass spectrometry (MS) to obtain organic chemical species data suitable for source apportionment modeling of soil-derived coarse particulate matter (PM10) dust on ambient filters. A laboratory resuspension apparatus was used with known soils to generate simulated receptor filter samples loaded with approximately 0.4 mg of PM10 dust, which is within the range of mass loading on ambient filters. Py-GC/MS at 740 degrees C generated five times more resolvable compounds than were obtained with thermal desorption GC/MS at 315 degrees C. The identified compounds were consistent with literature from Py experiments using larger samples of bulk soils. A subset of 91 organic species out of the 178 identified Py products was used as input to CMB8 software in a demonstration of source apportionment using laboratory-generated mixtures simulating ambient filter samples. The 178 quantified organic species obtained by Py of soil samples is an improvement compared with the 38 organic species obtained by thermal desorption of soils and the four functionally defined organic fractions reported by thermal/ optical reflectance. Significant differences in the concentration of specific species were seen between samples from different sites, both geographically distant and close, using analysis of variance and cluster analysis. This feasibility study showed that Py-GC/MS can generate useful source profile data for receptor modeling and justifies continued method development.
The gene transcript profile responses to metal oxide nanoparticles was studied using human cell l... more The gene transcript profile responses to metal oxide nanoparticles was studied using human cell lines derived from the colon and skin tumors. Much of the research on nanoparticle toxicology has focused on models of inhalation and intact skin exposure, and effects of ingestion exposure and application to diseased skin are relatively unknown. Powders of nominally nanosized SiO2, TiO2, ZnO and Fe2O3 were chosen because these substances are widely used in consumer products. The four oxides were evaluated using colon-derived cell lines, RKO and CaCo-2, and ZnO and TiO2 were evaluated further using skin-derived cell lines HaCaT and SK Mel-28. ZnO induced the most notable gene transcription changes, even though this material was applied at the lowest concentration. Nano-sized and conventional ZnO induced similar responses suggesting common mechanisms of action. The results showed neither a non-specific response pattern common to all substances nor synergy of the particles with TNF-α cotreatment. The response to ZnO was not consistent with a pronounced proinflammatory signature, but involved changes in metal metabolism, chaperonin proteins, and protein folding genes. This response was observed in all cell lines when ZnO was in contact with the human cells. When the cells were exposed to soluble Zn, the genes involved in metal metabolism were induced but the genes involved in protein refoldling were unaffected. This provides some of the first data on the effects of commercial metal oxide nanoparticles on human colon-derived and skin-derived cells.
Recognition of temperature is a critical element of sensory perception and allows mammals to eval... more Recognition of temperature is a critical element of sensory perception and allows mammals to evaluate both their external environment and internal status. The respiratory epithelium is constantly exposed to the external environment and prolonged inhalation of cold air is detrimental to human airways. However, the mechanisms responsible for adverse effects elicited by cold air on the human airways are poorly understood. TRPM8 is a well established cold-and menthol-sensing cation channel. We recently discovered a functional cold-and menthol-sensing variant of the TRPM8 ion channel in human lung epithelial cells. The present study explores the hypothesis that this TRPM8 variant mediates airway cell inflammatory responses elicited by cold air/temperatures. Here we show that activation of the TRPM8 variant in human lung epithelial cells leads to increased expression of several cytokine and chemokine genes, including interleukins 1 , 1 , 4, 6, 8, 13, GMCSF, and TNF . Our results provide new insights into mechanisms that potentially control airway inflammation due to inhalation of cold air, and suggest a possible role for the TRPM8 variant in the pathophysiology of asthma.
Research on pulverized fuel burnout mechanisms derives its primary motivation from industrial pro... more Research on pulverized fuel burnout mechanisms derives its primary motivation from industrial problems with the utilization of high-carbon fly ash. The severity of these problems depends on residual carbon properties, but combustion research has focused almost exclusively on the degree of burnout, which determines only the amount of residual carbon. This paper presents measurements of three important residual carbon properties: reactivity, surface area, and adsorptivity toward surfactants, the latter property being the most critical for ash quality in many concrete applications. The paper investigates the independent effects of fuel type and combustion conditions by analyzing samples derived from bench, pilot, and commercial scale combustion processes. Residual carbon surface area is observed to be strongly dependent on parent fuel type ranging from about 1 m 2 /g for petroleum coke residues to values up to 400 m 2 /g for lowrank coal residues. Surfactant adsorptivity also varies strongly with parent fuel and shows the best correlation with residual carbon surface area in pores larger than 2 nm, likely because of the large size of surfactant molecules and slow liquid-phase diffusion. The surfactant adsorptivity is also sensitive to the presence of carbon surface oxides introduced by low-temperature oxidation using air or ozone. The data clearly indicate that oxides suppress adsorptivity, and that the underlying mechanism is an increase in carbon surface polarity and hydrophilicity. Controlled pilot-scale experiments show that air staging for NO x control often produces residual carbon with a high adsorptivity, even when adsorptivity is expressed per gram of carbon. Successful staging conditions that lead both to low-NO x and high burnout are observed to produce residual carbons with lower specific surface area and adsorptivity, so poor carbon quality is not an intrinsic feature of all low-NO x flames.
Public reporting burden for the collection of information is estimated to average 1 hour per resp... more Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Public reporting burden for the collection of information is estimated to average 1 hour per resp... more Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Source profiles (fractional mass abundances and uncertainties) for use in chemical mass balance (... more Source profiles (fractional mass abundances and uncertainties) for use in chemical mass balance (CMB) source apportionment are reported for soil dust from unpaved roads and desert lands. The objectives were to add to the library of source composition profiles available for CMB studies, and to provide data on the variation in wind-blown dust composition between particle sizes and geographical locations. Samples were resuspended and sampled through PM 1 , PM 2.5 and PM 10 inlets onto filters, then chemically analyzed for 40 elements, seven ions and eight carbon fractions. Air quality management would benefit from technology that can distinguish soil dust from sites in different geographical locations and sites with different land uses. Five geographical clusters representing Ft Bliss, TX, Dona Ana County, NM, Ft Irwin, CA, the west desert and the Canyonlands, UT, were examined. Distinctive differences were found between sites within a cluster and these differences were comparable to the differences between cluster averages. Some sites showed small differences in chemical composition between particle sizes, but these differences were less than the differences observed between nearby geographical locations. Dust emissions from sites with uniform geology have distinctive source profiles that may be useful for CMB receptor modeling. Heterogeneous regions, defined by land management boundaries, will require extensive field sampling to develop representative composite source profiles.
AIHA journal : a journal for the science of occupational and environmental health and safety
Particle emissions from manual shielded metal arc welding of carbon steel were sampled in a typic... more Particle emissions from manual shielded metal arc welding of carbon steel were sampled in a typical industrial maintenance and metal fabrication workplace environment. Particle number measurements over the size range from 14 nm to 10 microm using a scanning mobility particle sizer and an optical particle counter showed that welding produced an approximately lognormal particle mode with a 120 nm count median and a geometric standard deviation of 2.07. This study produced welding particle number concentrations on the order of 2 x 10(5)/cm(3) in the building air 8.5 m away from the welding. Workplace exposure samples were below the current 8-hour American Conference of Governmental Industrial Hygienists mass concentration threshold limit value of 5 mg/m(3). Submicron particles comprised 80% of the total aerosol mass collected by a cascade impactor during welding. The concentration of larger particles was indistinguishable from indoor background. Microscopy showed that the welding emiss...
The induction of cytokines by airway cells in vitro has been widely used to assess the effects of... more The induction of cytokines by airway cells in vitro has been widely used to assess the effects of ambient and occupational particles. This study measured cytotoxicity and the release of the proinflammatory cytokines IL-6 and IL-8 by human bronchial epithelial cells treated with manufactured nano- and micron-sized particles of Al2O3, CeO2, Fe2O3, NiO, SiO2, and TiO2, with soil-derived particles from fugitive dust sources, and with the positive controls LPS, TNF-alpha, and VOSO4. The nano-sized particles were not consistently more potent than an equal mass of micron-sized particles of the same nominal composition for the induction of IL-6 and IL-8 secretion in the in vitro models used in this study. The manufactured pure oxides were much less potent than natural PM2.5 particles derived from soil dust, and the cells were highly responsive to the positive controls. The nano-sized particles in the media caused artifacts in the measurement of IL-6 by ELISA due to adsorption of the cytokin...
ABSTRACT The ongoing search for specialty substances with unique physical and chemical properties... more ABSTRACT The ongoing search for specialty substances with unique physical and chemical properties has motivated the development of numerous types of metal oxide nanomaterials, but concerns remain regarding biological effects of particles that are comparable in size to ultrafine air pollution (d < 100 nm). Much of the nanoparticle toxicological research has been on inhalation and intact-skin dermal exposures. Lung epithelial cells exposed to oxide nanoparticles show diverse responses, most notably upregulation of pro-inflammatory signaling pathways. This chapter addresses potential etiologies, mechanisms, and methodologies for investigating potential unforeseen toxicities of nanoparticles that are likely to occur in skin as nanoproducts become more and more available.
A novel methodology to detect unlabeled inorganic nanoparticles was experimentally demonstrated u... more A novel methodology to detect unlabeled inorganic nanoparticles was experimentally demonstrated using a mixture of nano-sized (70 nm) and submicron (250 nm) silicon dioxide particles added to mammalian tissue. The size and concentration of environmentally relevant inorganic particles in a tissue sample can be determined by a procedure consisting of matrix digestion, particle recovery by centrifugation, size separation by sedimentation field-flow fractionation (SdFFF), and detection by light scattering.
The University of Utah, Massachusetts Institute of Technology (MIT), Reaction Engineering Interna... more The University of Utah, Massachusetts Institute of Technology (MIT), Reaction Engineering International (REI) and ABB/Combustion Engineering have joined together in this research proposal to develop fundamental understanding regarding the impact of fuel and combustion changes on ignition stability and flame characteristics because these critically affect NOx emissions, carbon burnout, and emissions of air toxics. Existing laboratory and bench scale facilities are being used to generate critical missing data which will be used to improve the NOx and carbon burnout submodels in comprehensive combustion simulation tools currently being used by industrial boiler manufacturers. To ensure effective and timely transfer of this technology, a major manufacturer (ABB) and a combustion model supplier (REI) have been included as part of the team from the early conception of the proposal. The program was awarded and initiated during the past quarter. Preliminary discussions were held regarding the coals which will be used throughout the program. Current plans are to include several coals where large scale field data are available. Work also began to modify the University of Utah pulverized fuel furnace for premixed combustion studies which are designed to help define the role of char nitrogen oxidation in the overall formation mechanism. The report discusses the premixed burner, FTIR analysis of nitrogenous species, and temperature measurement.
An accurate estimation of the CO/COâ ratio at the surface of an ash inclusion in coal during comb... more An accurate estimation of the CO/COâ ratio at the surface of an ash inclusion in coal during combustion is necessary to predict the equilibrium partial pressure of volatile reduced metal species inside the burning particle and the rate of vaporization of metal oxides. Assumptions that have been made previously for the CO/COâ ratio at the surface of mineral inclusions are compared to those obtained from a steady state detailed kinetics code for a single porous particle (SKIPPY). The detailed kinetic simulations from SKIPPY for varying particle sizes and bulk gas compositions were used to develop algebraic expressions for the CO/COâ ratio that can be incorporated into metal vaporization sub-models run as a post processor to detailed furnace simulations.
The overall objective of the present project was to identify and assess strategies and solutions ... more The overall objective of the present project was to identify and assess strategies and solutions for the management of industry problems related to carbon in ash. Specific issues addressed included:
Cultured lung cells provide an alternative to animal exposures for comparing the effects of diffe... more Cultured lung cells provide an alternative to animal exposures for comparing the effects of different types of air pollution particles. Studies of particulate matter in vitro have reported proinflammatory cytokine signaling in response to many types of environmental particles, but there have been few studies comparing identical treatments in multiple cell types or identical cells with alternative cell culture protocols. We compared soil-derived, diesel, coal fly ash, titanium dioxide, and kaolin particles along with soluble vanadium and lipopolysaccharide, applied to airway-derived cells grown in submerged culture. Cell types included A549, BEAS-2B, RAW 264.7, and primary macrophages. The cell culture models (specific combinations of cell types and culture conditions) were reproducibly different in the cytokine signaling responses to the suite of treatments. Further, Interleukin-6 (IL-6) response to the treatments changed when the same cells, BEAS-2B, were grown in KGM versus LHC-9 media or in media containing bovine serum. The effect of changing media composition was reversible over multiple changes of media type. Other variables tested included culture well size and degree of confluence. The observation that sensitivity of a cell type to environmental agonists can be manipulated by modifying culture conditions suggests a novel approach for studying biochemical mechanisms of particle toxicity.
Cultured human lung epithelial cells (BEAS-2B) were treated in vitro with PM 2.5 -enriched partic... more Cultured human lung epithelial cells (BEAS-2B) were treated in vitro with PM 2.5 -enriched particles of soil-derived mineral dust from nine sites in the western United States. The particle samples simulate windblown dust and vehicle-generated emissions from unpaved roads. Five of the sites yielded relatively benign dust. Particles from three sites caused IL-6 release when cells were treated for 24 h at doses from 20 to 80 μg/cm 2 , and particles from one site were highly cytotoxic. The particle components or characteristics that caused the IL-6 release were stable at temperatures below 150°C, but were inactivated by treatment at 300-550°C. The active factors were also associated predominantly with the insoluble fraction, and were partially attenuated by leaching with aqueous and organic solvents. The IL-6 release caused by the particles was much greater than the cytokine response to either lipopolysaccharide (LPS) or to surrogate particles of titanium dioxide mixed with LPS, suggesting that endotoxin was not a major factor in the inflammatory response. The release of IL-8 in response to particle treatment was qualitatively similar to the IL-6 response, but release of TNF-α was not detected at the 24-h time point. The combined results support the hypothesis that some ambient dusts from geological sources can cause cell death and cytokine release in a lung cell line that is widely used as an in vitro model to study mechanisms of environmental respiratory injury.
Although primary particle emissions of ash from coal-fired power plants are well controlled, coal... more Although primary particle emissions of ash from coal-fired power plants are well controlled, coal fly ash (CFA) can still remain a significant fraction of the overall particle exposure for some plant workers and highly impacted communities. The effect of CFA on pulmonary and systemic inflammation and injury was measured in male Sprague-Dawley rats exposed to filtered air or CFA for 4 h/day for 3 days. The average concentration of CFA particulate matter less than 2.5 mm (PM 2.5 ) was 1400 mg/m 3 , of which 600 mg/m 3 was PM 1 . Animals were examined 18 and 36 h postexposure. Chemical analysis of CFA detected silicon, calcium, aluminum, and iron as major components. Total number of neutrophils in bronchoalveolar lavage fluid (BALF) following exposure to CFA was significantly increased along with significantly elevated blood neutrophils. Exposure to CFA caused slight increases in macrophage inflammatory protein-2, and marked increases in transferrin in BALF. Interleukin-1b and total antioxidant potential in lung tissues were also increased in rats exposed to CFA. Histological examination of lung tissue demonstrated focal alveolar septal thickening and increased cellularity in select alveoli immediately beyond terminal bronchioles. These responses are consistent with the ability of CFA to induce mild neutrophilic inflammation in the lung and blood following short-term exposure at levels that could be occupationally relevant. However, when comparing the effects of CFA with those of concentrated ambient particles, CFA does not appear to have greater potency to cause pulmonary alterations. This study furthers our understanding of possible mechanisms by which specific sources of particulate air pollution affect human health.
Journal of the Air & Waste Management Association, 2000
Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biom... more Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biomass, and waste, and PM from internal combustion (IC) engines burning gasoline and diesel, are a significant source of primary particles smaller than 2.5 µm (PM 2.5 ) in urban areas. Combustion-generated particles are generally smaller than geologically produced dust and have unique chemical composition and morphology. The fundamental processes affecting formation of combustion PM and the emission characteristics of important applications are reviewed. Particles containing transition metals, ultrafine particles, and soot are emphasized because these types of particles have been studied extensively, and their emissions are controlled by the fuel composition and the oxidant-temperature-mixing history from the flame to the stack. There is a need for better integration of the combustion, air pollution control, atmospheric chemistry, and inhalation health research communities. Epidemiology has demonstrated that susceptible individuals are being harmed by ambient PM. Particle surface area, number of ultrafine particles, bioavailable transition metals, polycyclic aromatic hydrocarbons (PAH), and other particle-bound organic compounds are suspected to be more important than particle mass in determining the effects of air pollution. Time-and size-resolved PM measurements are needed for testing mechanistic toxicological hypotheses, for characterizing the relationship between combustion operating conditions and transient emissions, and for source apportionment studies to develop air quality plans. Citations are provided to more specialized reviews, and the concluding comments make suggestions for further research.
Journal of the Air & Waste Management Association, 2006
This study tested the feasibility of using pyrolysis (Py)-gas chromatography (GC)/mass spectromet... more This study tested the feasibility of using pyrolysis (Py)-gas chromatography (GC)/mass spectrometry (MS) to obtain organic chemical species data suitable for source apportionment modeling of soil-derived coarse particulate matter (PM10) dust on ambient filters. A laboratory resuspension apparatus was used with known soils to generate simulated receptor filter samples loaded with approximately 0.4 mg of PM10 dust, which is within the range of mass loading on ambient filters. Py-GC/MS at 740 degrees C generated five times more resolvable compounds than were obtained with thermal desorption GC/MS at 315 degrees C. The identified compounds were consistent with literature from Py experiments using larger samples of bulk soils. A subset of 91 organic species out of the 178 identified Py products was used as input to CMB8 software in a demonstration of source apportionment using laboratory-generated mixtures simulating ambient filter samples. The 178 quantified organic species obtained by Py of soil samples is an improvement compared with the 38 organic species obtained by thermal desorption of soils and the four functionally defined organic fractions reported by thermal/ optical reflectance. Significant differences in the concentration of specific species were seen between samples from different sites, both geographically distant and close, using analysis of variance and cluster analysis. This feasibility study showed that Py-GC/MS can generate useful source profile data for receptor modeling and justifies continued method development.
The gene transcript profile responses to metal oxide nanoparticles was studied using human cell l... more The gene transcript profile responses to metal oxide nanoparticles was studied using human cell lines derived from the colon and skin tumors. Much of the research on nanoparticle toxicology has focused on models of inhalation and intact skin exposure, and effects of ingestion exposure and application to diseased skin are relatively unknown. Powders of nominally nanosized SiO2, TiO2, ZnO and Fe2O3 were chosen because these substances are widely used in consumer products. The four oxides were evaluated using colon-derived cell lines, RKO and CaCo-2, and ZnO and TiO2 were evaluated further using skin-derived cell lines HaCaT and SK Mel-28. ZnO induced the most notable gene transcription changes, even though this material was applied at the lowest concentration. Nano-sized and conventional ZnO induced similar responses suggesting common mechanisms of action. The results showed neither a non-specific response pattern common to all substances nor synergy of the particles with TNF-α cotreatment. The response to ZnO was not consistent with a pronounced proinflammatory signature, but involved changes in metal metabolism, chaperonin proteins, and protein folding genes. This response was observed in all cell lines when ZnO was in contact with the human cells. When the cells were exposed to soluble Zn, the genes involved in metal metabolism were induced but the genes involved in protein refoldling were unaffected. This provides some of the first data on the effects of commercial metal oxide nanoparticles on human colon-derived and skin-derived cells.
Recognition of temperature is a critical element of sensory perception and allows mammals to eval... more Recognition of temperature is a critical element of sensory perception and allows mammals to evaluate both their external environment and internal status. The respiratory epithelium is constantly exposed to the external environment and prolonged inhalation of cold air is detrimental to human airways. However, the mechanisms responsible for adverse effects elicited by cold air on the human airways are poorly understood. TRPM8 is a well established cold-and menthol-sensing cation channel. We recently discovered a functional cold-and menthol-sensing variant of the TRPM8 ion channel in human lung epithelial cells. The present study explores the hypothesis that this TRPM8 variant mediates airway cell inflammatory responses elicited by cold air/temperatures. Here we show that activation of the TRPM8 variant in human lung epithelial cells leads to increased expression of several cytokine and chemokine genes, including interleukins 1 , 1 , 4, 6, 8, 13, GMCSF, and TNF . Our results provide new insights into mechanisms that potentially control airway inflammation due to inhalation of cold air, and suggest a possible role for the TRPM8 variant in the pathophysiology of asthma.
Research on pulverized fuel burnout mechanisms derives its primary motivation from industrial pro... more Research on pulverized fuel burnout mechanisms derives its primary motivation from industrial problems with the utilization of high-carbon fly ash. The severity of these problems depends on residual carbon properties, but combustion research has focused almost exclusively on the degree of burnout, which determines only the amount of residual carbon. This paper presents measurements of three important residual carbon properties: reactivity, surface area, and adsorptivity toward surfactants, the latter property being the most critical for ash quality in many concrete applications. The paper investigates the independent effects of fuel type and combustion conditions by analyzing samples derived from bench, pilot, and commercial scale combustion processes. Residual carbon surface area is observed to be strongly dependent on parent fuel type ranging from about 1 m 2 /g for petroleum coke residues to values up to 400 m 2 /g for lowrank coal residues. Surfactant adsorptivity also varies strongly with parent fuel and shows the best correlation with residual carbon surface area in pores larger than 2 nm, likely because of the large size of surfactant molecules and slow liquid-phase diffusion. The surfactant adsorptivity is also sensitive to the presence of carbon surface oxides introduced by low-temperature oxidation using air or ozone. The data clearly indicate that oxides suppress adsorptivity, and that the underlying mechanism is an increase in carbon surface polarity and hydrophilicity. Controlled pilot-scale experiments show that air staging for NO x control often produces residual carbon with a high adsorptivity, even when adsorptivity is expressed per gram of carbon. Successful staging conditions that lead both to low-NO x and high burnout are observed to produce residual carbons with lower specific surface area and adsorptivity, so poor carbon quality is not an intrinsic feature of all low-NO x flames.
Public reporting burden for the collection of information is estimated to average 1 hour per resp... more Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Public reporting burden for the collection of information is estimated to average 1 hour per resp... more Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Source profiles (fractional mass abundances and uncertainties) for use in chemical mass balance (... more Source profiles (fractional mass abundances and uncertainties) for use in chemical mass balance (CMB) source apportionment are reported for soil dust from unpaved roads and desert lands. The objectives were to add to the library of source composition profiles available for CMB studies, and to provide data on the variation in wind-blown dust composition between particle sizes and geographical locations. Samples were resuspended and sampled through PM 1 , PM 2.5 and PM 10 inlets onto filters, then chemically analyzed for 40 elements, seven ions and eight carbon fractions. Air quality management would benefit from technology that can distinguish soil dust from sites in different geographical locations and sites with different land uses. Five geographical clusters representing Ft Bliss, TX, Dona Ana County, NM, Ft Irwin, CA, the west desert and the Canyonlands, UT, were examined. Distinctive differences were found between sites within a cluster and these differences were comparable to the differences between cluster averages. Some sites showed small differences in chemical composition between particle sizes, but these differences were less than the differences observed between nearby geographical locations. Dust emissions from sites with uniform geology have distinctive source profiles that may be useful for CMB receptor modeling. Heterogeneous regions, defined by land management boundaries, will require extensive field sampling to develop representative composite source profiles.
AIHA journal : a journal for the science of occupational and environmental health and safety
Particle emissions from manual shielded metal arc welding of carbon steel were sampled in a typic... more Particle emissions from manual shielded metal arc welding of carbon steel were sampled in a typical industrial maintenance and metal fabrication workplace environment. Particle number measurements over the size range from 14 nm to 10 microm using a scanning mobility particle sizer and an optical particle counter showed that welding produced an approximately lognormal particle mode with a 120 nm count median and a geometric standard deviation of 2.07. This study produced welding particle number concentrations on the order of 2 x 10(5)/cm(3) in the building air 8.5 m away from the welding. Workplace exposure samples were below the current 8-hour American Conference of Governmental Industrial Hygienists mass concentration threshold limit value of 5 mg/m(3). Submicron particles comprised 80% of the total aerosol mass collected by a cascade impactor during welding. The concentration of larger particles was indistinguishable from indoor background. Microscopy showed that the welding emiss...
The induction of cytokines by airway cells in vitro has been widely used to assess the effects of... more The induction of cytokines by airway cells in vitro has been widely used to assess the effects of ambient and occupational particles. This study measured cytotoxicity and the release of the proinflammatory cytokines IL-6 and IL-8 by human bronchial epithelial cells treated with manufactured nano- and micron-sized particles of Al2O3, CeO2, Fe2O3, NiO, SiO2, and TiO2, with soil-derived particles from fugitive dust sources, and with the positive controls LPS, TNF-alpha, and VOSO4. The nano-sized particles were not consistently more potent than an equal mass of micron-sized particles of the same nominal composition for the induction of IL-6 and IL-8 secretion in the in vitro models used in this study. The manufactured pure oxides were much less potent than natural PM2.5 particles derived from soil dust, and the cells were highly responsive to the positive controls. The nano-sized particles in the media caused artifacts in the measurement of IL-6 by ELISA due to adsorption of the cytokin...
ABSTRACT The ongoing search for specialty substances with unique physical and chemical properties... more ABSTRACT The ongoing search for specialty substances with unique physical and chemical properties has motivated the development of numerous types of metal oxide nanomaterials, but concerns remain regarding biological effects of particles that are comparable in size to ultrafine air pollution (d < 100 nm). Much of the nanoparticle toxicological research has been on inhalation and intact-skin dermal exposures. Lung epithelial cells exposed to oxide nanoparticles show diverse responses, most notably upregulation of pro-inflammatory signaling pathways. This chapter addresses potential etiologies, mechanisms, and methodologies for investigating potential unforeseen toxicities of nanoparticles that are likely to occur in skin as nanoproducts become more and more available.
A novel methodology to detect unlabeled inorganic nanoparticles was experimentally demonstrated u... more A novel methodology to detect unlabeled inorganic nanoparticles was experimentally demonstrated using a mixture of nano-sized (70 nm) and submicron (250 nm) silicon dioxide particles added to mammalian tissue. The size and concentration of environmentally relevant inorganic particles in a tissue sample can be determined by a procedure consisting of matrix digestion, particle recovery by centrifugation, size separation by sedimentation field-flow fractionation (SdFFF), and detection by light scattering.
The University of Utah, Massachusetts Institute of Technology (MIT), Reaction Engineering Interna... more The University of Utah, Massachusetts Institute of Technology (MIT), Reaction Engineering International (REI) and ABB/Combustion Engineering have joined together in this research proposal to develop fundamental understanding regarding the impact of fuel and combustion changes on ignition stability and flame characteristics because these critically affect NOx emissions, carbon burnout, and emissions of air toxics. Existing laboratory and bench scale facilities are being used to generate critical missing data which will be used to improve the NOx and carbon burnout submodels in comprehensive combustion simulation tools currently being used by industrial boiler manufacturers. To ensure effective and timely transfer of this technology, a major manufacturer (ABB) and a combustion model supplier (REI) have been included as part of the team from the early conception of the proposal. The program was awarded and initiated during the past quarter. Preliminary discussions were held regarding the coals which will be used throughout the program. Current plans are to include several coals where large scale field data are available. Work also began to modify the University of Utah pulverized fuel furnace for premixed combustion studies which are designed to help define the role of char nitrogen oxidation in the overall formation mechanism. The report discusses the premixed burner, FTIR analysis of nitrogenous species, and temperature measurement.
An accurate estimation of the CO/COâ ratio at the surface of an ash inclusion in coal during comb... more An accurate estimation of the CO/COâ ratio at the surface of an ash inclusion in coal during combustion is necessary to predict the equilibrium partial pressure of volatile reduced metal species inside the burning particle and the rate of vaporization of metal oxides. Assumptions that have been made previously for the CO/COâ ratio at the surface of mineral inclusions are compared to those obtained from a steady state detailed kinetics code for a single porous particle (SKIPPY). The detailed kinetic simulations from SKIPPY for varying particle sizes and bulk gas compositions were used to develop algebraic expressions for the CO/COâ ratio that can be incorporated into metal vaporization sub-models run as a post processor to detailed furnace simulations.
The overall objective of the present project was to identify and assess strategies and solutions ... more The overall objective of the present project was to identify and assess strategies and solutions for the management of industry problems related to carbon in ash. Specific issues addressed included:
Cultured lung cells provide an alternative to animal exposures for comparing the effects of diffe... more Cultured lung cells provide an alternative to animal exposures for comparing the effects of different types of air pollution particles. Studies of particulate matter in vitro have reported proinflammatory cytokine signaling in response to many types of environmental particles, but there have been few studies comparing identical treatments in multiple cell types or identical cells with alternative cell culture protocols. We compared soil-derived, diesel, coal fly ash, titanium dioxide, and kaolin particles along with soluble vanadium and lipopolysaccharide, applied to airway-derived cells grown in submerged culture. Cell types included A549, BEAS-2B, RAW 264.7, and primary macrophages. The cell culture models (specific combinations of cell types and culture conditions) were reproducibly different in the cytokine signaling responses to the suite of treatments. Further, Interleukin-6 (IL-6) response to the treatments changed when the same cells, BEAS-2B, were grown in KGM versus LHC-9 media or in media containing bovine serum. The effect of changing media composition was reversible over multiple changes of media type. Other variables tested included culture well size and degree of confluence. The observation that sensitivity of a cell type to environmental agonists can be manipulated by modifying culture conditions suggests a novel approach for studying biochemical mechanisms of particle toxicity.
Cultured human lung epithelial cells (BEAS-2B) were treated in vitro with PM 2.5 -enriched partic... more Cultured human lung epithelial cells (BEAS-2B) were treated in vitro with PM 2.5 -enriched particles of soil-derived mineral dust from nine sites in the western United States. The particle samples simulate windblown dust and vehicle-generated emissions from unpaved roads. Five of the sites yielded relatively benign dust. Particles from three sites caused IL-6 release when cells were treated for 24 h at doses from 20 to 80 μg/cm 2 , and particles from one site were highly cytotoxic. The particle components or characteristics that caused the IL-6 release were stable at temperatures below 150°C, but were inactivated by treatment at 300-550°C. The active factors were also associated predominantly with the insoluble fraction, and were partially attenuated by leaching with aqueous and organic solvents. The IL-6 release caused by the particles was much greater than the cytokine response to either lipopolysaccharide (LPS) or to surrogate particles of titanium dioxide mixed with LPS, suggesting that endotoxin was not a major factor in the inflammatory response. The release of IL-8 in response to particle treatment was qualitatively similar to the IL-6 response, but release of TNF-α was not detected at the 24-h time point. The combined results support the hypothesis that some ambient dusts from geological sources can cause cell death and cytokine release in a lung cell line that is widely used as an in vitro model to study mechanisms of environmental respiratory injury.
Although primary particle emissions of ash from coal-fired power plants are well controlled, coal... more Although primary particle emissions of ash from coal-fired power plants are well controlled, coal fly ash (CFA) can still remain a significant fraction of the overall particle exposure for some plant workers and highly impacted communities. The effect of CFA on pulmonary and systemic inflammation and injury was measured in male Sprague-Dawley rats exposed to filtered air or CFA for 4 h/day for 3 days. The average concentration of CFA particulate matter less than 2.5 mm (PM 2.5 ) was 1400 mg/m 3 , of which 600 mg/m 3 was PM 1 . Animals were examined 18 and 36 h postexposure. Chemical analysis of CFA detected silicon, calcium, aluminum, and iron as major components. Total number of neutrophils in bronchoalveolar lavage fluid (BALF) following exposure to CFA was significantly increased along with significantly elevated blood neutrophils. Exposure to CFA caused slight increases in macrophage inflammatory protein-2, and marked increases in transferrin in BALF. Interleukin-1b and total antioxidant potential in lung tissues were also increased in rats exposed to CFA. Histological examination of lung tissue demonstrated focal alveolar septal thickening and increased cellularity in select alveoli immediately beyond terminal bronchioles. These responses are consistent with the ability of CFA to induce mild neutrophilic inflammation in the lung and blood following short-term exposure at levels that could be occupationally relevant. However, when comparing the effects of CFA with those of concentrated ambient particles, CFA does not appear to have greater potency to cause pulmonary alterations. This study furthers our understanding of possible mechanisms by which specific sources of particulate air pollution affect human health.
Journal of the Air & Waste Management Association, 2000
Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biom... more Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biomass, and waste, and PM from internal combustion (IC) engines burning gasoline and diesel, are a significant source of primary particles smaller than 2.5 µm (PM 2.5 ) in urban areas. Combustion-generated particles are generally smaller than geologically produced dust and have unique chemical composition and morphology. The fundamental processes affecting formation of combustion PM and the emission characteristics of important applications are reviewed. Particles containing transition metals, ultrafine particles, and soot are emphasized because these types of particles have been studied extensively, and their emissions are controlled by the fuel composition and the oxidant-temperature-mixing history from the flame to the stack. There is a need for better integration of the combustion, air pollution control, atmospheric chemistry, and inhalation health research communities. Epidemiology has demonstrated that susceptible individuals are being harmed by ambient PM. Particle surface area, number of ultrafine particles, bioavailable transition metals, polycyclic aromatic hydrocarbons (PAH), and other particle-bound organic compounds are suspected to be more important than particle mass in determining the effects of air pollution. Time-and size-resolved PM measurements are needed for testing mechanistic toxicological hypotheses, for characterizing the relationship between combustion operating conditions and transient emissions, and for source apportionment studies to develop air quality plans. Citations are provided to more specialized reviews, and the concluding comments make suggestions for further research.
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Papers by John Veranth