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Sample records for ultrafine particles development

  1. Ultrafine particles in cities.

    PubMed

    Kumar, Prashant; Morawska, Lidia; Birmili, Wolfram; Paasonen, Pauli; Hu, Min; Kulmala, Markku; Harrison, Roy M; Norford, Leslie; Britter, Rex

    2014-05-01

    Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts.

  2. Combustion derived ultrafine particles induce cytochrome P-450 expression in specific lung compartments in the developing neonatal and adult rat

    PubMed Central

    Chan, Jackie K. W.; Vogel, Christoph F.; Baek, Jaeeun; Kodani, Sean D.; Uppal, Ravi S.; Bein, Keith J.; Anderson, Donald S.

    2013-01-01

    Vehicle exhaust is rich in polycyclic aromatic hydrocarbons (PAH) and can be a dominant contributor to ultrafine urban particulate matter (PM). Exposure to ultrafine PM is correlated with respiratory infections and asthmatic symptoms in young children. The lung undergoes substantial growth, alveolarization, and cellular maturation within the first years of life, which may be impacted by environmental pollutants such as PM. PAHs in PM can serve as ligands for the aryl hydrocarbon receptor (AhR) that induces expression of certain isozymes in the cytochrome P-450 superfamily, such as CYP1A1 and CYP1B1, localized in specific lung cell types. Although AhR activation and induction has been widely studied, its context within PM exposure and impact on the developing lung is poorly understood. In response, we have developed a replicable ultrafine premixed flame particle (PFP) generating system and used in vitro and in vivo models to define PM effects on AhR activation in the developing lung. We exposed 7-day neonatal and adult rats to a single 6-h PFP exposure and determined that PFPs cause significant parenchymal toxicity in neonates. PFPs contain weak AhR agonists that upregulate AhR-xenobiotic response element activity and expression and are capable inducers of CYP1A1 and CYP1B1 expression in both ages with different spatial and temporal patterns. Neonatal CYP1A1 expression was muted and delayed compared with adults, possibly because of differences in the enzyme maturation. We conclude that the inability of neonates to sufficiently adapt in response to PFP exposure may, in part, explain their susceptibility to PFP and urban ultrafine PM. PMID:23502512

  3. Combustion derived ultrafine particles induce cytochrome P-450 expression in specific lung compartments in the developing neonatal and adult rat.

    PubMed

    Chan, Jackie K W; Vogel, Christoph F; Baek, Jaeeun; Kodani, Sean D; Uppal, Ravi S; Bein, Keith J; Anderson, Donald S; Van Winkle, Laura S

    2013-05-15

    Vehicle exhaust is rich in polycyclic aromatic hydrocarbons (PAH) and can be a dominant contributor to ultrafine urban particulate matter (PM). Exposure to ultrafine PM is correlated with respiratory infections and asthmatic symptoms in young children. The lung undergoes substantial growth, alveolarization, and cellular maturation within the first years of life, which may be impacted by environmental pollutants such as PM. PAHs in PM can serve as ligands for the aryl hydrocarbon receptor (AhR) that induces expression of certain isozymes in the cytochrome P-450 superfamily, such as CYP1A1 and CYP1B1, localized in specific lung cell types. Although AhR activation and induction has been widely studied, its context within PM exposure and impact on the developing lung is poorly understood. In response, we have developed a replicable ultrafine premixed flame particle (PFP) generating system and used in vitro and in vivo models to define PM effects on AhR activation in the developing lung. We exposed 7-day neonatal and adult rats to a single 6-h PFP exposure and determined that PFPs cause significant parenchymal toxicity in neonates. PFPs contain weak AhR agonists that upregulate AhR-xenobiotic response element activity and expression and are capable inducers of CYP1A1 and CYP1B1 expression in both ages with different spatial and temporal patterns. Neonatal CYP1A1 expression was muted and delayed compared with adults, possibly because of differences in the enzyme maturation. We conclude that the inability of neonates to sufficiently adapt in response to PFP exposure may, in part, explain their susceptibility to PFP and urban ultrafine PM.

  4. Ultrafine Condensation Particle Counter Instrument Handbook

    SciTech Connect

    Kuang, C.

    2016-02-01

    The Model 3776 Ultrafine Condensation Particle Counter (UCPC; pictured in Appendix A) is designed for researchers interested in airborne particles smaller than 20 nm. With sensitivity to particles down to 2.5 nm in diameter, this UCPC is ideally suited for atmospheric and climate research, particle formation and growth studies, combustion and engine exhaust research, and nanotechnology research.

  5. Exposure to ultrafine particles in asphalt work.

    PubMed

    Elihn, Karine; Ulvestad, Bente; Hetland, Siri; Wallen, Anna; Randem, Britt Grethe

    2008-12-01

    An epidemiologic study has demonstrated that asphalt workers show increased loss of lung function and an increase of biomarkers of inflammation over the asphalt paving season. The aim of this study was to investigate which possible agent(s) causes the inflammatory reaction, with emphasis on ultrafine particles. The workers' exposure to total dust, polycyclic aromatic hydrocarbons, and NO(2) was determined by personal sampling. Exposure to ultrafine particles was measured by means of particle counters and scanning mobility particle sizer mounted on a van following the paving machine. The fractions of organic and elemental carbon were determined. Asphalt paving workers were exposed to ultrafine particles with medium concentration of about 3.4 x 10(4)/cm(3). Ultrafine particles at the paving site originated mainly from asphalt paving activities and traffic exhaust; most seemed to originate from asphalt fumes. Oil mist exceeded occupational limits on some occasions. Diesel particulate matter was measured as elemental carbon, which was low, around 3 microg/m(3). NO(2) and total dust did not exceed limits. Asphalt pavers were exposed to relatively high concentrations of ultrafine particles throughout their working day, with possible adverse health effects.

  6. Personal exposure to ultrafine particles.

    PubMed

    Wallace, Lance; Ott, Wayne

    2011-01-01

    Personal exposure to ultrafine particles (UFP) can occur while people are cooking, driving, smoking, operating small appliances such as hair dryers, or eating out in restaurants. These exposures can often be higher than outdoor concentrations. For 3 years, portable monitors were employed in homes, cars, and restaurants. More than 300 measurement periods in several homes were documented, along with 25 h of driving two cars, and 22 visits to restaurants. Cooking on gas or electric stoves and electric toaster ovens was a major source of UFP, with peak personal exposures often exceeding 100,000 particles/cm³ and estimated emission rates in the neighborhood of 10¹² particles/min. Other common sources of high UFP exposures were cigarettes, a vented gas clothes dryer, an air popcorn popper, candles, an electric mixer, a toaster, a hair dryer, a curling iron, and a steam iron. Relatively low indoor UFP emissions were noted for a fireplace, several space heaters, and a laser printer. Driving resulted in moderate exposures averaging about 30,000 particles/cm³ in each of two cars driven on 17 trips on major highways on the East and West Coasts. Most of the restaurants visited maintained consistently high levels of 50,000-200,000 particles/cm³ for the entire length of the meal. The indoor/outdoor ratios of size-resolved UFP were much lower than for PM₂.₅ or PM₁₀, suggesting that outdoor UFP have difficulty in penetrating a home. This in turn implies that outdoor concentrations of UFP have only a moderate effect on personal exposures if indoor sources are present. A time-weighted scenario suggests that for typical suburban nonsmoker lifestyles, indoor sources provide about 47% and outdoor sources about 36% of total daily UFP exposure and in-vehicle exposures add the remainder (17%). However, the effect of one smoker in the home results in an overwhelming increase in the importance of indoor sources (77% of the total).

  7. Traffic and nucleation events as main sources of ultrafine particles in high-insolation developed world cities

    NASA Astrophysics Data System (ADS)

    Brines, M.; Dall'Osto, M.; Beddows, D. C. S.; Harrison, R. M.; Gómez-Moreno, F.; Núñez, L.; Artíñano, B.; Costabile, F.; Gobbi, G. P.; Salimi, F.; Morawska, L.; Sioutas, C.; Querol, X.

    2015-05-01

    Road traffic emissions are often considered the main source of ultrafine particles (UFP, diameter smaller than 100 nm) in urban environments. However, recent studies worldwide have shown that - in high-insolation urban regions at least - new particle formation events can also contribute to UFP. In order to quantify such events we systematically studied three cities located in predominantly sunny environments: Barcelona (Spain), Madrid (Spain) and Brisbane (Australia). Three long-term data sets (1-2 years) of fine and ultrafine particle number size distributions (measured by SMPS, Scanning Mobility Particle Sizer) were analysed. Compared to total particle number concentrations, aerosol size distributions offer far more information on the type, origin and atmospheric evolution of the particles. By applying k-means clustering analysis, we categorized the collected aerosol size distributions into three main categories: "Traffic" (prevailing 44-63% of the time), "Nucleation" (14-19%) and "Background pollution and Specific cases" (7-22%). Measurements from Rome (Italy) and Los Angeles (USA) were also included to complement the study. The daily variation of the average UFP concentrations for a typical nucleation day at each site revealed a similar pattern for all cities, with three distinct particle bursts. A morning and an evening spike reflected traffic rush hours, whereas a third one at midday showed nucleation events. The photochemically nucleated particles' burst lasted 1-4 h, reaching sizes of 30-40 nm. On average, the occurrence of particle size spectra dominated by nucleation events was 16% of the time, showing the importance of this process as a source of UFP in urban environments exposed to high solar radiation. Nucleation events lasting for 2 h or more occurred on 55% of the days, this extending to > 4 h in 28% of the days, demonstrating that atmospheric conditions in urban environments are not favourable to the growth of photochemically nucleated particles. In

  8. Ultrafine particle deposition in subjects with asthma.

    PubMed

    Chalupa, David C; Morrow, Paul E; Oberdörster, Günter; Utell, Mark J; Frampton, Mark W

    2004-06-01

    Ambient air particles in the ultrafine size range (diameter < 100 nm) may contribute to the health effects of particulate matter. However, there are few data on ultrafine particle deposition during spontaneous breathing, and none in people with asthma. Sixteen subjects with mild to moderate asthma were exposed for 2 hr, by mouthpiece, to ultrafine carbon particles with a count median diameter (CMD) of 23 nm and a geometric standard deviation of 1.6. Deposition was measured during spontaneous breathing at rest (minute ventilation, 13.3 +/- 2.0 L/min) and exercise (minute ventilation, 41.9 +/- 9.0 L/min). The mean +/- SD fractional deposition was 0.76 +/- 0.05 by particle number and 0.69 +/- 0.07 by particle mass concentration. The number deposition fraction increased as particle size decreased, reaching 0.84 +/- 0.03 for the smallest particles (midpoint CMD = 8.7 nm). No differences between sexes were observed. The deposition fraction increased during exercise to 0.86 +/- 0.04 and 0.79 +/- 0.05 by particle number and mass concentration, respectively, and reached 0.93 +/- 0.02 for the smallest particles. Experimental deposition data exceeded model predictions during exercise. The deposition at rest was greater in these subjects with asthma than in previously studied healthy subjects (0.76 +/- 0.05 vs. 0.65 +/- 0.10, p < 0.001). The efficient respiratory deposition of ultrafine particles increases further in subjects with asthma. Key words: air pollution, asthma, deposition, dosimetry, inhalation, ultrafine particles.

  9. Filtration of ultrafine metallic particles in industry.

    PubMed

    Bémer, D; Morele, Y; Régnier, R

    2015-01-01

    Thermal metal spraying, metal cutting and arc welding processes generate large quantities of ultrafine particles that cause the irreversible clogging of industrial filters. The aim of the study performed was to identify the causes of the clogging of cartridge filters and investigate other paths for cleaning them. This study required the development of a test bench capable of reproducing a thermal spraying process to test the performances of different filtration techniques. This test instrument first, permitted the precise characterization of the aerosol generated by the process and, second, defined the clogging and cleaning conditions for filters. Several parameters were tested: the type of filter, online and off-line cleaning, pre-coating, cleaning by jets of high-speed compressed air via a probe.

  10. A chemical analyzer for charged ultrafine particles

    NASA Astrophysics Data System (ADS)

    Gonser, S. G.; Held, A.

    2013-04-01

    New particle formation is a frequent phenomenon in the atmosphere and of major significance for the earth's climate and human health. To date the mechanisms leading to the nucleation of particles as well as to aerosol growth are not completely understood. A lack of appropriate measurement equipment for online analysis of the chemical composition of freshly nucleated particles is one major limitation. We have developed a Chemical Analyzer for Charged Ultrafine Particles (CAChUP) capable of analyzing particles with diameters below 30 nm. A bulk of size separated particles is collected electrostatically on a metal filament, resistively desorbed and consequently analyzed for its molecular composition in a time of flight mass spectrometer. We report of technical details as well as characterization experiments performed with the CAChUP. Our instrument was tested in the laboratory for its detection performance as well as for its collection and desorption capabilities. The manual application of known masses of camphene (C10H16) to the desorption filament resulted in a detection limit between 0.5 and 5 ng, and showed a linear response of the mass spectrometer. Flow tube experiments of 25 nm diameter secondary organic aerosol from ozonolysis of alpha-pinene also showed a linear relation between collection time and the mass spectrometer's signal intensity. The resulting mass spectra from the collection experiments are in good agreement with published work on particles generated by the ozonolysis of alpha-pinene. A sensitivity study shows that the current setup of CAChUP is ready for laboratory measurements and for the observation of new particle formation events in the field.

  11. A chemical analyzer for charged ultrafine particles

    NASA Astrophysics Data System (ADS)

    Gonser, S. G.; Held, A.

    2013-09-01

    New particle formation is a frequent phenomenon in the atmosphere and of major significance for the Earth's climate and human health. To date the mechanisms leading to the nucleation of particles as well as to aerosol growth are not completely understood. A lack of appropriate measurement equipment for online analysis of the chemical composition of freshly nucleated particles is one major limitation. We have developed a Chemical Analyzer for Charged Ultrafine Particles (CAChUP) capable of analyzing particles with diameters below 30 nm. A bulk of size-separated particles is collected electrostatically on a metal filament, resistively desorbed and subsequently analyzed for its molecular composition in a time of flight mass spectrometer. We report on technical details as well as characterization experiments performed with the CAChUP. Our instrument was tested in the laboratory for its detection performance as well as for its collection and desorption capabilities. The manual application of defined masses of camphene (C10H16) to the desorption filament resulted in a detection limit between 0.5 and 5 ng, and showed a linear response of the mass spectrometer. Flow tube experiments of 25 nm diameter secondary organic aerosol from ozonolysis of alpha-pinene also showed a linear relation between collection time and the mass spectrometer's signal intensity. The resulting mass spectra from the collection experiments are in good agreement with published work on particles generated by the ozonolysis of alpha-pinene. A sensitivity study shows that the current setup of CAChUP is ready for laboratory measurements and for the observation of new particle formation events in the field.

  12. Focusing particle concentrator with application to ultrafine particles

    DOEpatents

    Hering, Susanne; Lewis, Gregory; Spielman, Steven R.

    2013-06-11

    Technology is presented for the high efficiency concentration of fine and ultrafine airborne particles into a small fraction of the sampled airflow by condensational enlargement, aerodynamic focusing and flow separation. A nozzle concentrator structure including an acceleration nozzle with a flow extraction structure may be coupled to a containment vessel. The containment vessel may include a water condensation growth tube to facilitate the concentration of ultrafine particles. The containment vessel may further include a separate carrier flow introduced at the center of the sampled flow, upstream of the acceleration nozzle of the nozzle concentrator to facilitate the separation of particle and vapor constituents.

  13. Concentrated ambient ultrafine particle exposure induces cardiac change in young healthy volunteers

    EPA Science Inventory

    Exposure to ambient ultrafine particles has been associated with cardiopulmonary toxicity and mortality. Adverse effects specifically linked to ultrafine particles include loss of sympathovagal balance and altered hemostasis. To characterize the effects of ultrafine particles in ...

  14. Characterizing and predicting ultrafine particle counts in Canadian classrooms during the winter months: Model development and evaluation

    SciTech Connect

    Weichenthal, Scott Dufresne, Andre; Infante-Rivard, Claire; Joseph, Lawrence

    2008-03-15

    School classrooms are potentially important micro-environments for childhood exposures owing to the large amount of time children spend in these locations. While a number of airborne contaminants may be present in schools, to date few studies have examined ultrafine particle (0.02-1 {mu}m) (UFP) levels in classrooms. In this study, our objective was to characterize UFP counts (cm{sup -3}) in classrooms during the winter months and to develop a model to predict such exposures based on ambient weather conditions and outdoor UFPs, as well as classroom characteristics such as size, temperature, relative humidity, and carbon dioxide levels. In total, UFP count data were collected on 60 occasions in 37 occupied classrooms at one elementary school and one secondary school in Pembroke, Ontario. On average, outdoor UFP levels exceeded indoor measures by 8989 cm{sup -3} (95% confidence interval (CI): 6382, 11 596), and classroom UFP counts were similar at both schools with a combined average of 5017 cm{sup -3} (95% CI: 4300, 5734). Of the variables examined only wind speed and outdoor UFPs were important determinants of classrooms UFP levels. Specifically, each 10 km/h increase in wind speed corresponded to an 1873 cm{sup -3} (95% CI: 825, 2920) decrease in classroom UFP counts, and each 10 000 cm{sup -3} increase in outdoor UFPs corresponded to a 1550 cm{sup -3} (95% CI: 930, 2171) increase in classroom UFP levels. However, high correlations between these two predictors meant that the independent effects of wind speed and outdoor UFPs could not be separated in multivariable models, and only outdoor UFP counts were included in the final predictive model. To evaluate model performance, classroom UFP counts were collected for 8 days at two new schools and compared to predicted values based on outdoor UFP measures. A moderate correlation was observed between measured and predicted classroom UFP counts (r=0.63) for both schools combined, but this relationship was not valid on

  15. Characterizing and predicting ultrafine particle counts in Canadian classrooms during the winter months: model development and evaluation.

    PubMed

    Weichenthal, Scott; Dufresne, André; Infante-Rivard, Claire; Joseph, Lawrence

    2008-03-01

    School classrooms are potentially important micro-environments for childhood exposures owing to the large amount of time children spend in these locations. While a number of airborne contaminants may be present in schools, to date few studies have examined ultrafine particle (0.02-1 microm) (UFP) levels in classrooms. In this study, our objective was to characterize UFP counts (cm(-3)) in classrooms during the winter months and to develop a model to predict such exposures based on ambient weather conditions and outdoor UFPs, as well as classroom characteristics such as size, temperature, relative humidity, and carbon dioxide levels. In total, UFP count data were collected on 60 occasions in 37 occupied classrooms at one elementary school and one secondary school in Pembroke, Ontario. On average, outdoor UFP levels exceeded indoor measures by 8989 cm(-3) (95% confidence interval (CI): 6382, 11596), and classroom UFP counts were similar at both schools with a combined average of 5017 cm(-3) (95% CI: 4300, 5734). Of the variables examined only wind speed and outdoor UFPs were important determinants of classrooms UFP levels. Specifically, each 10 km/h increase in wind speed corresponded to an 1873 cm(-3) (95% CI: 825, 2920) decrease in classroom UFP counts, and each 10000 cm(-3) increase in outdoor UFPs corresponded to a 1550 cm(-3) (95% CI: 930, 2171) increase in classroom UFP levels. However, high correlations between these two predictors meant that the independent effects of wind speed and outdoor UFPs could not be separated in multivariable models, and only outdoor UFP counts were included in the final predictive model. To evaluate model performance, classroom UFP counts were collected for 8 days at two new schools and compared to predicted values based on outdoor UFP measures. A moderate correlation was observed between measured and predicted classroom UFP counts (r=0.63) for both schools combined, but this relationship was not valid on days in which a strong

  16. Study of fine and ultrafine particles for coal cleaning

    SciTech Connect

    Birlingmair, D.; Buttermore, W.; Chmielewski, T.; Pollard, J.

    1990-04-01

    During the second quarter of work on this new project, critical review of the literature continued. Several new references related to gravity separation were identified and evaluated. A synopsis was assembled to summarize techniques developed by various researchers for the float/sink separation of ultrafine coal. In the reviewed literature, it was commonly concluded that substantial improvements in washability results for ultrafine coals can be obtained only through the application of dynamic (centrifugal) procedures, and through the use of dispersing aids such as ultrasound and surfactants. These results suggest the presence of physicochemical phenomena, typical of colloidal systems. In theoretical studies this quarter, the effects of Brownian motion on fine particle sedimentation have been identified and theoretically quantitated. The interaction between Brownian and gravitational forces was calculated, and a model was prepared to permit estimation of critical particle size in float/sink separations. In laboratory studies this quarter, aliquots of Upper Freeport coal were prepared and subjected to laboratory float/sink separations to investigate the relative effectiveness of static and centrifugal techniques for fine and ultrafine coal. This series will verify results of earlier work and provide a basis for comparing the effects which may result from further modifications to the separation techniques resulting from insights gained in the basic phenomena governing float/sink processes. 15 refs., 6 figs., 1 tab.

  17. Ultrafine particle measurement and related EPA research studies

    EPA Science Inventory

    Webinar slides to present information on measuring ultrafine particles at the request of the 2013 MARAMA Monitoring Committee. The talk covers near-road monitoring, instrument intercomparison, and general overview of UFP monitoring technology.

  18. CARDIOVASCULAR EFFECTS OF ULTRAFINE CARBON PARTICLES IN HYPERTENSIVE RATS (SHR)

    EPA Science Inventory

    Rationale: Epidemiological evidence suggests that ultrafine particles are associated with adverse cardiovascular effects, specifically in elderly individuals with preexisting cardiovascular disease. The objective of this study was (i) to assess cardiopulmonary responses in adult ...

  19. The sintering behavior of ultrafine alumina particles

    SciTech Connect

    Bonevich, J.E.; Marks, L.D. )

    1992-06-01

    Ultrafine particles (UFPs) of aluminum oxide were prepared by an arc discharge, sintered in a custom-built ultrahigh vacuum (UHV) furnace system, and characterized in a high resolution electron microscope (HREM) operating under UHV conditions. The UFPs produced range in size from 20 to 50 nm and have highly faceted surfaces. The atomic structure of the UFPs corresponds to the cubic ({gamma}) and orthorhombic ({delta}) variants of the spinel structure. Sintering in these UFPs demonstrates three major issues. Surface faceting plays a major role in determining the final sintering geometry with sintering occurring predominantly on the closed-packed {l brace}111{r brace} facets. Surface diffusion is the predominant mechanism for sintering, as evidenced by the fact that many sintered particles have their initial adhesion structure locked-in' during sintering with no reorientation occurring. Furthermore, the necks formed during sintering have well-defined, atomically-sharp contact angles which suggests that the neck growth process is controlled by the faceted structures and may be modeled by a mechanism similar to crystal growth due to ledges, grain boundaries, and twins. The driving force for sintering can be considered as a chemical potential difference between facet surfaces and the neck region.

  20. Polymer degradation and ultrafine particles - Potential inhalation hazards for astronauts

    NASA Technical Reports Server (NTRS)

    Ferin, J.; Oberdoerster, G.

    1992-01-01

    To test the hypothesis that exposure to ultrafine particles results in an increased interstiatilization of the particles which is accompanied by an acute pathological inflammation, rats were exposed to titanium dioxide (TiO2) particles by intratracheal instillation and by inhalation. Both acute intratracheal instillation and subchronic inhalation studies on rats show that ultrafine TiO2 particles access the pulmonary interstitium to a larger extent than fine particles and that they elicit an inflammatory response as indicated by PMN increase in lavaged cells. The release of ultrafine particles into the air of an enclosed environment from a thermodegradation event or from other sources is a potential hazard for astronauts. Knowing the mechanisms of action is a prerequisite for technical or medical countermeasures.

  1. VERSATILE AEROSOL CONCENTRATION ENRICHMENT SYSTEM (VACES) FOR SIMULTANEOUS IN VIVO AND IN VITRO EVALUATION OF TOXIC EFFECTS OF ULTRAFINE, FINE AND COARSE AMBIENT PARTICLES. PART I: DEVELOPMENT AND LABORATORY CHARACTERIZATION. (R827352C001)

    EPA Science Inventory

    This study presents the development and bench-testing of a versatile aerosol concentration enrichment system (VACES) capable of simultaneously concentrating ambient particles of the coarse, fine and ultrafine size fractions for conducting in vivo and in vitro studies. The VACE...

  2. [Ultrafine particle number concentration and size distribution of vehicle exhaust ultrafine particles].

    PubMed

    Lu, Ye-qiang; Chen, Qiu-fang; Sun, Zai; Cai, Zhi-liang; Yang, Wen-jun

    2014-09-01

    Ultrafine particle (UFP) number concentrations obtained from three different vehicles were measured using fast mobility particle sizer (FMPS) and automobile exhaust gas analyzer. UFP number concentration and size distribution were studied at different idle driving speeds. The results showed that at a low idle speed of 800 rmin-1 , the emission particle number concentration was the lowest and showed a increasing trend with the increase of idle speed. The majority of exhaust particles were in Nuclear mode and Aitken mode. The peak sizes were dominated by 10 nm and 50 nm. Particle number concentration showed a significantly sharp increase during the vehicle acceleration process, and was then kept stable when the speed was stable. In the range of 0. 4 m axial distance from the end of the exhaust pipe, the particle number concentration decayed rapidly after dilution, but it was not obvious in the range of 0. 4-1 m. The number concentration was larger than the background concentration. Concentration of exhaust emissions such as CO, HC and NO showed a reducing trend with the increase of idle speed,which was in contrast to the emission trend of particle number concentration.

  3. Ultrafine particles preserved in the fault gouge of the Arima-Takatsuki Tectonic Line, Japan

    NASA Astrophysics Data System (ADS)

    Asayama, S.; Hirono, T.

    2015-12-01

    Coseismic friction causes comminution, grain-size reduction, and amorphization of minerals. These ultrafine particles are preserved in the fault: for example, particles (size of some tens of nanometers) have been reported only in the latest slip zone within the Taiwan Chelungpu fault that slipped during the 1999 Chi-Chi earthquake. On the other hand, these ultrafine particles might dissolve in the pore water and then disappear, because amorphous fine minerals have generally high water solubility. This indicates that the preserved ultrafine particles have potential as a proxy for identifying the slip zone of the most recent earthquake along a fault. However, the occurrence in the active faults has not been fully reported. Thus, we investigated the slip zone within the Arima-Takatsuki Tectonic Line considered to have slipped at the 1596 Keicho-Fushimi earthquake, and reported mineral particles within the slip zone together with the development of advanced method to quantify amorphous component.

  4. Selective separation of ultra-fine particles by magnetophoresis

    SciTech Connect

    Ying, T.; Prenger, F. Coyne; Wingo, R. M.; Worl, L. A.

    2002-01-01

    The selective and-specific extraction of species of interest fiom local environmental and other sample sources are importaut fbr scientific research, industrial processes, and environmental applications. A novel process for selective separation of ultrafine particles using 'magnetophoresis' is investigated. The principle of this process is that the direction and velocity of particle movement in a magnetic field are determined by magnetic, gravitational, and drag fbrces. By controlling these fbrces, one is able to control the migration rates of different species and then magnetically fiactionate mixtures of species into discrete groups. This study demonstrated for the fist time the selective separation of various species, such as iron (111) oxide, cupric (11) oxide, samarium (In) oxide, and cerium (III) oxide, by magnetophoresis. To better understand this phenomenon, a fbrce-balance model was developed that provides a good interpretation of the experimental results.

  5. LASER DESORPTION IONIZATION OF ULTRAFINE AEROSOL PARTICLES. (R823980)

    EPA Science Inventory

    On-line analysis of ultrafine aerosol particle in the 12 to 150 nm size range is performed by
    laser desorption/ionization. Particles are size selected with a differential mobility analyzer and then
    sent into a linear time-of-flight mass spectrometer where they are ablated w...

  6. Recycling concrete: An undiscovered source of ultrafine particles

    NASA Astrophysics Data System (ADS)

    Kumar, Prashant; Morawska, Lidia

    2014-06-01

    While concrete recycling is practiced worldwide, there are many unanswered questions in relation to ultrafine particle (UFP; Dp < 100 nm) emissions and exposure around recycling sites. In particular: (i) Does recycling produce UFPs and in what quantities? (ii) How do they disperse around the source? (iii) What impact does recycling have on ambient particle number concentrations (PNCs) and exposure? (iv) How effective are commonly used dust respirators to limit exposure? We measured size-resolved particles in the 5-560 nm range at five distances between 0.15 and 15.15 m that were generated by an experimentally simulated concrete recycling source and found that: (i) the size distributions were multimodal, with up to ˜93% of total PNC in the UFP size range; and (ii) dilution was a key particle transformation mechanism. UFPs showed a much slower decay rate, requiring ˜62% more distance to reach 10% of their initial concentration compared with their larger counterparts in the 100-560 nm size range. Compared with typical urban exposure during car journeys, exposure decay profiles showed up to ˜5 times higher respiratory deposition within 10 m of the source. Dust respirators were found to remove half of total PNC; however the removal factor for UFPs was only ˜57% of that observed in the 100-560 nm size range. These findings highlight a need for developing an understanding of the nature of the particles as well as for better control measures to limit UFP exposure.

  7. CARDIOVASCULAR RESPONSES TO ULTRAFINE CARBON PARTICLE EXPOSURES IN RATS

    EPA Science Inventory

    TD-02-042 (U. KODAVANTI) GPRA # 10108

    Cardiovascular Responses to Ultrafine Carbon Particle Exposures in Rats.
    V. Harder1, B. Lentner1, A. Ziesenis1, E. Karg1, L. Ruprecht1, U. Kodavanti2, A. Stampfl3, J. Heyder1, H. Schulz1
    GSF- Institute for Inhalation Biology1, I...

  8. Calibration of TSI model 3025 ultrafine condensation particle counter

    SciTech Connect

    Kesten, J.; Reineking, A.; Porstendoerfer, J. )

    1991-01-01

    The registration efficiency of the TSI model 3025 ultrafine condensation particle counter for Ag and NaCl particles of between 2 and 20 nm in diameter was determined. Taking into account the different shapes of the input aerosol size distributions entering the differential mobility analyzer (DMA) and the transfer function of the DMA, the counting efficiencies of condensation nucleus counters (CNC) for monodisperse Ag and NaCl particles were estimated. In addition, the dependence of the CNC registration efficiency on the particle concentration was investigated.

  9. Miniaturized ultrafine particle sizer and monitor

    NASA Technical Reports Server (NTRS)

    Chen, Da-Ren (Inventor); Qi, Chaolong (Inventor)

    2011-01-01

    An apparatus for measuring particle size distribution includes a charging device and a precipitator. The charging device includes a corona that generates charged ions in response to a first applied voltage, and a charger body that generates a low energy electrical field in response to a second applied voltage in order to channel the charged ions out of the charging device. The corona tip and the charger body are arranged relative to each other to direct a flow of particles through the low energy electrical field in a direction parallel to a direction in which the charged ions are channeled out of the charging device. The precipitator receives the plurality of particles from the charging device, and includes a disk having a top surface and an opposite bottom surface, wherein a predetermined voltage is applied to the top surface and the bottom surface to precipitate the plurality of particles.

  10. [Distribution of atmospheric ultrafine particles during haze weather in Hangzhou].

    PubMed

    Chen, Qiu-Fang; Sun, Zai; Xie, Xiao-Fang

    2014-08-01

    Atmospheric ultrafine particles (UFPs) were monitored with fast mobility particle sizer (FMPS) in continuous haze weather and the haze fading process during December 6 to 11, 2013 in Hangzhou. Particle concentration and size distribution were studied associated with meteorological factors. The results showed that number concentrations were the highest at night and began to reduce in the morning. There was a small peak at 8 o'clock in the morning and 18 o'clock in the afternoon. It showed an obvious peak traffic source, which indicated that traffic emissions played a great role in the atmospheric pollution. During haze weather, the highest number concentration of UFPs reached 8 x 10(4) cm(-3). Particle size spectrum distribution was bimodal, the peak particle sizes were 15 nm and 100 nm respectively. Majority of UFPs were Aitken mode and Accumulation mode and the size of most particles concentrated near 100 nm. Average CMD(count medium diameter) was 85.89 nm. During haze fading process, number concentration and particles with size around 100 nm began to reduce and peak size shifted to small size. Nuclear modal particles increased and were more than accumulation mode. Average CMD was 58.64 nm. Meteorological factors such as the visibility and wind were negatively correlated with the particle number concentration. Correlation coefficient R were -0.225 and - 0.229. The humidity was correlated with number concentration. Correlation coefficient R was 0.271. The atmosphere was stable in winter and the level temperature had small correlation with number concentration. Therefore, study on distribution of atmospheric ultrafine particles during haze weather had the significance on the formation mechanism and control of haze weather.

  11. Process and apparatus for producing ultrafine explosive particles

    DOEpatents

    McGowan, Michael J.

    1992-10-20

    A method and an improved eductor apparatus for producing ultrafine explosive particles is disclosed. The explosive particles, which when incorporated into a binder system, have the ability to propagate in thin sheets, and have very low impact sensitivity and very high propagation sensitivity. A stream of a solution of the explosive dissolved in a solvent is thoroughly mixed with a stream of an inert nonsolvent by obtaining nonlaminar flow of the streams by applying pressure against the flow of the nonsolvent stream, to thereby diverge the stream as it contacts the explosive solution, and violently agitating the combined stream to rapidly precipitate the explosive particles from the solution in the form of generally spheroidal, ultrafine particles. The two streams are injected coaxially through continuous, concentric orifices of a nozzle into a mixing chamber. Preferably, the nonsolvent stream is injected centrally of the explosive solution stream. The explosive solution stream is injected downstream of and surrounds the nonsolvent solution stream for a substantial distance prior to being ejected into the mixing chamber.

  12. Fine and ultrafine particle emissions from microwave popcorn.

    PubMed

    Zhang, Q; Avalos, J; Zhu, Y

    2014-04-01

    This study characterized fine (PM2.5 ) and ultrafine particle (UFP, diameter < 100 nm) emissions from microwave popcorn and analyzed influential factors. Each pre-packed popcorn bag was cooked in a microwave oven enclosed in a stainless steel chamber for 3 min. The number concentration and size distribution of UFPs and PM2.5 mass concentration were measured inside the chamber repeatedly for five different flavors under four increasing power settings using either the foil-lined original package or a brown paper bag. UFPs and PM2.5 generated by microwaving popcorn were 150-560 and 350-800 times higher than the emissions from microwaving water, respectively. About 90% of the total particles emitted were in the ultrafine size range. The emitted PM concentrations varied significantly with flavor. Replacing the foil-lined original package with a brown paper bag significantly reduced the peak concentration by 24-87% for total particle number and 36-70% for PM2.5 . A positive relationship was observed between both UFP number and PM2.5 mass and power setting. The emission rates of microwave popcorn ranged from 1.9 × 10(10) to 8.0 × 10(10) No./min for total particle number and from 134 to 249 μg/min for PM2.5 .

  13. Concentrations of ultrafine particles at a highway toll collection booth and exposure implications for toll collectors.

    PubMed

    Cheng, Yu-Hsiang; Huang, Cheng-Hsiung; Huang, Hsiao-Lin; Tsai, Chuen-Jinn

    2010-12-15

    Research regarding the magnitude of ultrafine particle levels at highway toll stations is limited. This study measured ambient concentrations of ultrafine particles at a highway toll station from October 30 to November 1 and November 5 to November 6, 2008. A scanning mobility particle sizer was used to measure ultrafine particle concentrations at a ticket/cash tollbooth. Levels of hourly average ultrafine particles at the tollbooth were about 3-6 times higher than those in urban backgrounds, indicating that a considerable amount of ultrafine particles are exhausted from passing vehicles. A bi-modal size distribution pattern with a dominant mode at about <6 nm and a minor mode at about 40 nm was observed at the tollbooth. The high amounts of nanoparticles in this study can be attributed to gas-to-particle reactions in fresh fumes emitted directly from vehicles. The influences of traffic volume, wind speed, and relative humidity on ultrafine particle concentrations were also determined. High ambient concentrations of ultrafine particles existed under low wind speed, low relative humidity, and high traffic volume. Although different factors account for high ambient concentrations of ultrafine particles at the tollbooth, measurements indicate that toll collectors who work close to traffic emission sources have a high exposure risk.

  14. SOURCE STRENGTHS OF ULTRAFINE AND FINE PARTICLES DUE TO COOKING WITH A GAS STOVE

    EPA Science Inventory

    Cooking, particularly frying, is an important source of particles indoors. Few studies have measured a full range of particle sizes, including ultrafine particles, produced during cooking. In this study, semicontinuous instruments with fine size discriminating ability were us...

  15. Process for making ultra-fine ceramic particles

    DOEpatents

    Stangle, Gregory C.; Venkatachari, Koththavasal R.; Ostrander, Steven P.; Schulze, Walter A.

    1995-01-01

    A process for producing ultra-fine ceramic particles in which droplets are formed from a ceramic precursor mixture containing a metal cation, a nitrogen-containing fuel, a solvent, and an anion capable of participating in an anionic oxidation-reduction reaction with the nitrogen containing fuel. The nitrogen-containing fuel contains at least three nitrogen atoms, at least one oxygen atom, and at least one carbon atom. The ceramic precursor mixture is dried to remove at least 85 weight percent of the solvent, and the dried mixture is then ignited to form a combusted powder.

  16. Flotation classification of ultrafine particles -- A novel classification approach

    SciTech Connect

    Qiu Guanzhou; Luo Lin; Hu Yuehua; Xu Jin; Wang Dianzuo

    1995-12-31

    This paper introduces a novel classification approach named the flotation classification approach which works by controlling interactions between particles. It differs considerably from the conventional classification processes operating on mechanical forces. In the present test, the micro-bubble flotation technology is grafted onto hydro-classification. Selective aggregation and dispersion of ultrafine particles are achieved through governing the interactions in the classification process. A series of laboratory classification tests for {minus}44 gm kaolin have been conducted on a classification column. As a result, about 92% recovery for minus 2 {micro}m size fraction Kaolin in the final product is obtained. In addition, two criteria for the classification are set up. Finally, a principle of classifying and controlling the interactions between particles is discussed in terms of surface thermodynamics and hydrodynamics.

  17. Exposure to inhalable, respirable, and ultrafine particles in welding fume.

    PubMed

    Lehnert, Martin; Pesch, Beate; Lotz, Anne; Pelzer, Johannes; Kendzia, Benjamin; Gawrych, Katarzyna; Heinze, Evelyn; Van Gelder, Rainer; Punkenburg, Ewald; Weiss, Tobias; Mattenklott, Markus; Hahn, Jens-Uwe; Möhlmann, Carsten; Berges, Markus; Hartwig, Andrea; Brüning, Thomas

    2012-07-01

    This investigation aims to explore determinants of exposure to particle size-specific welding fume. Area sampling of ultrafine particles (UFP) was performed at 33 worksites in parallel with the collection of respirable particles. Personal sampling of respirable and inhalable particles was carried out in the breathing zone of 241 welders. Median mass concentrations were 2.48 mg m(-3) for inhalable and 1.29 mg m(-3) for respirable particles when excluding 26 users of powered air-purifying respirators (PAPRs). Mass concentrations were highest when flux-cored arc welding (FCAW) with gas was applied (median of inhalable particles: 11.6 mg m(-3)). Measurements of particles were frequently below the limit of detection (LOD), especially inside PAPRs or during tungsten inert gas welding (TIG). However, TIG generated a high number of small particles, including UFP. We imputed measurements particle counts) and for the respirable or inhalable fraction of the welding fume (expressed as their mass) remains challenging.

  18. Numerical Model for Ultra-fine Particles in the Absence and Presence of Gravity

    NASA Astrophysics Data System (ADS)

    Dutt, Meenakshi; Elliott, James A.

    2009-06-01

    Length scales of particles and their surrounding medium strongly determines the nature of their interactions with one another and their responses to external fields. We are interested in systems of ultra-fine particles (0.1-1.0 micron) such as volcanic ash, soot from forest fires, solid aerosols, or fine powders for pharmaceutical inhalation applications. We have a developed a numerical model which captures the dominant physical interactions which control the behavior of these systems. The adhesive interactions between the particles use the Derjaguin-Muller-Toporov (DMT) adhesion theory along with the van der Waals attraction. The elastic restoring forces are modeled by the Hertz's contact model, and require details of material properties such as the Young's modulus and Poisson ratio. Commencing with a three dimensional gas of ultra-fine particles, the absence of gravity does not produce any noticeable clustering. The presence of gravity initially generates a large population of clusters with small number of particles, as the particles settle. The initial population of small clusters or single particles which have settled decrease with time as more particles, or clusters, agglomerate with one another. Our final results show clusters containing 10 to 100 particles, with a larger population of small clusters. We present details of the model, and some preliminary results which demonstrate the influence of the particle surface properties on the clustering dynamics of these systems, in the absence and presence of gravity (M. Dutt, J. A. Elliott, et al. in press).

  19. Nanotoxicology: An Emerging Discipline Evolving from Studies of Ultrafine Particles

    PubMed Central

    Oberdörster, Günter; Oberdörster, Eva; Oberdörster, Jan

    2005-01-01

    Although humans have been exposed to airborne nanosized particles (NSPs; < 100 nm) throughout their evolutionary stages, such exposure has increased dramatically over the last century due to anthropogenic sources. The rapidly developing field of nanotechnology is likely to become yet another source through inhalation, ingestion, skin uptake, and injection of engineered nanomaterials. Information about safety and potential hazards is urgently needed. Results of older bio-kinetic studies with NSPs and newer epidemiologic and toxicologic studies with airborne ultrafine particles can be viewed as the basis for the expanding field of nanotoxicology, which can be defined as safety evaluation of engineered nanostructures and nanodevices. Collectively, some emerging concepts of nanotoxicology can be identified from the results of these studies. When inhaled, specific sizes of NSPs are efficiently deposited by diffusional mechanisms in all regions of the respiratory tract. The small size facilitates uptake into cells and transcytosis across epithelial and endothelial cells into the blood and lymph circulation to reach potentially sensitive target sites such as bone marrow, lymph nodes, spleen, and heart. Access to the central nervous system and ganglia via translocation along axons and dendrites of neurons has also been observed. NSPs penetrating the skin distribute via uptake into lymphatic channels. Endocytosis and biokinetics are largely dependent on NSP surface chemistry (coating) and in vivo surface modifications. The greater surface area per mass compared with larger-sized particles of the same chemistry renders NSPs more active biologically. This activity includes a potential for inflammatory and pro-oxidant, but also antioxidant, activity, which can explain early findings showing mixed results in terms of toxicity of NSPs to environmentally relevant species. Evidence of mitochondrial distribution and oxidative stress response after NSP endocytosis points to a need

  20. Vascular effects of ultrafine particles in persons with type 2 diabetes

    EPA Science Inventory

    BACKGROUND: Diabetes confers an increased risk for cardiovascular effects of airborne particles. OBJECTIVE: We hypothesized that inhalation of elemental carbon ultrafine particles (UFP) would activate blood platelets and vascular endothelium in people with type 2 diabetes. ...

  1. UPREGULATION OF TISSUE FACTOR IN HUMAN ENDOTHELIAL CELLS FOLLOWING ULTRAFINE PARTICLE EXPOSURE

    EPA Science Inventory

    Epidemiology studies have linked the exposure to air pollutant particles with increased cardiovascular mortality and morbidity, but the mechanisms remain unknown. In our laboratory we have tested the hypothesis that the ultrafine fraction of ambient pollutant particles would cau...

  2. Infiltration of outdoor ultrafine particles into a test house.

    PubMed

    Rim, Donghyun; Wallace, Lance; Persily, Andrew

    2010-08-01

    Ultrafine particles (UFP) (<100 nm) have been related to adverse human health effects such as oxidative stress and cardiovascular mortality. However, human exposure to particles of outdoor origin is heavily dependent on their infiltration into homes. The infiltration factor (Finf) and its variation as a function of several factors becomes of enormous importance in epidemiological studies. The objective of this study is to investigate the transport of UFP into a residential building and to determine the functional dependence of infiltration on particle size and air change rate. A secondary objective was to estimate the values of the penetration coefficient P and composite deposition rate kcomp that enter into the definition of Finf. Using continuous measurements of indoor and outdoor concentrations of size-resolved particles ranging from 5 to 100 nm in a manufactured test house, particle penetration through the building, composite deposition, and the resulting value of Finf were calculated for two cases: closed windows and one window open 7.5 cm. Finf ranged from close to 0 (particles<10 nm) to 0.3 (particles>80 nm) with windows closed and from 0 to 0.6 with one window open. The penetration coefficient (closed windows) increased from about 0.2 for 10-nm particles to an asymptote near 0.6 for particles from 30-100 nm. Open window penetration coefficients were higher, ranging from 0.6 to 0.8. Closed-window composite deposition rates, which included losses to the furnace filter and to the ductwork as well as to interior surfaces, monotonically decreased from levels of about 1.5 h(-1) for 10-nm particles to 0.3 h(-1) for 100-nm particles. For the open-window case, composite deposition rates were higher for particles<20 nm, reaching values of 3.5 h(-1). Mean standard errors associated with estimates of P, kcomp, and Finf for two series of measurements ranged from 1.0% to 4.4%.

  3. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    SciTech Connect

    James K. Neathery; Gary Jacobs; Amitava Sarkar; Burtron H. Davis

    2005-09-30

    In this reporting period, a study of ultra-fine iron catalyst filtration was initiated to study the behavior of ultra-fine particles during the separation of Fischer-Tropsch Synthesis (FTS) liquids filtration. The overall focus of the program is with slurry-phase FTS in slurry bubble column reactor systems. Hydrocarbon products must be separated from catalyst particles before being removed from the reactor system. An efficient wax product/catalyst separation system is a key factor for optimizing operating costs for iron-based slurry-phase FTS. Previous work has focused on catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. With the current study, we are investigating how the filtration properties are affected by these chemical and physical changes of the catalyst slurry during activation/synthesis. The change of particle size during the slurry-phase FTS has monitored by withdrawing catalyst sample at different TOS. The measurement of dimension of the HRTEM images of samples showed a tremendous growth of the particles. Carbon rims of thickness 3-6 nm around the particles were observed. This growth in particle size was not due to carbon deposition on the catalyst. A conceptual design and operating philosophy was developed for an integrated wax filtration system for a 4 liter slurry bubble column reactor to be used in Phase II of this research program. The system will utilize a primary inertial hydroclone followed by a Pall Accusep cross-flow membrane. Provisions for cleaned permeate back-pulsing will be included to as a flux maintenance measure.

  4. Forecasting ultrafine particle concentrations from satellite and in situ observations

    NASA Astrophysics Data System (ADS)

    Crippa, P.; Castruccio, S.; Pryor, S. C.

    2017-02-01

    Recent innovations in remote sensing technologies and retrievals offer the potential for predicting ultrafine particle (UFP) concentrations from space. However, the use of satellite observations to provide predictions of near-surface UFP concentrations is limited by the high frequency of incomplete predictor values (due to missing observations), the lack of models that account for the temporal dependence of UFP concentrations, and the large uncertainty in satellite retrievals. Herein we present a novel statistical approach designed to address the first two limitations. We estimate UFP concentrations by using lagged estimates of UFP and concurrent satellite-based observations of aerosol optical properties, ultraviolet solar radiation flux, and trace gas concentrations, wherein an expectation maximization algorithm is used to impute missing values in the satellite observations. The resulting model of UFP (derived by using an autoregressive moving average model with exogenous inputs) explains 51 and 28% of the day-to-day variability in concentrations at two sites in eastern North America.

  5. Roadside measurements of ultrafine particles at a busy urban intersection.

    PubMed

    Wang, Yungang; Zhu, Yifang; Salinas, Robert; Ramirez, David; Karnae, Saritha; John, Kuruvilla

    2008-11-01

    A field sampling campaign on ultrafine particles (UFPs, diameter <100 nm) was conducted at a busy traffic intersection from December 2006 to June 2007 in Corpus Christi, TX. This traffic intersection consisted of South Padre Island Drive (SPID, Highway 358) and Staples Street. Traffic densities on SPID were 9102/hr and 7880/hr for weekdays and weekends, respectively. Staples Street traffic densities were 2795/hr and 2572/hr, respectively. There were approximately 3.7% heavy-duty diesel vehicles (HDDVs) on both roadways. Peak traffic flows occurred early in the morning and late in the evening during weekdays and around noon on weekends. The average UFP total number concentration collected by a condensation particle counter (CPC 3785; TSI) was 66 x 10(3) cm(-3). A direct relationship between the UFP number concentration and traffic density was observed, but the HDDV traffic density was found to be a better estimator of the UFP number concentration than total traffic density. A scanning mobility particle sizer (SMPS 3936 with DMA 3081 and CPC 3785, TSI) measuring the particle size distribution from 7 to 290 nm was rotated among four corners of the intersection. The upwind and downwind size distributions were both bimodal in shape, exhibiting a nucleation mode at 10-30 nm and a secondary mode at 50-70 nm. The highest and lowest particle concentrations were observed on the downwind and upwind sides of both roadways, respectively, indicating the importance of wind direction. Wind speed also played an important role in overall particle concentrations; UFP concentrations were inversely proportional to wind speed. A negative correlation was observed between particle number concentrations and ambient temperature. The particle number concentration was 3.5 times greater when traffic was idling at a red light than moving at a green light.

  6. Insights on wood combustion generated proinflammatory ultrafine particles (UFP).

    PubMed

    Corsini, Emanuela; Ozgen, Senem; Papale, Angela; Galbiati, Valentina; Lonati, Giovanni; Fermo, Paola; Corbella, Lorenza; Valli, Gianluigi; Bernardoni, Vera; Dell'Acqua, Manuela; Becagli, Silvia; Caruso, Donatella; Vecchi, Roberta; Galli, Corrado L; Marinovich, Marina

    2017-01-15

    This study aimed to collect, characterize ultrafine particles (UFP) generated from the combustion of wood pellets and logs (softwood and hardwood) and to evaluate their pro-inflammatory effects in THP-1 and A549 cells. Both cell lines responded to UFP producing interleukin-8 (IL-8), with wood log UFP being more active compared to pellet UFP. With the exception of higher effect observed with beech wood log UFP in THP-1, the ability of soft or hard woods to induce IL-8 release was similar. In addition, on weight mass, IL-8 release was similar or lower compared to diesel exhaust particles (DEP), arguing against higher biological activity of smaller size particles. UFP-induced IL-8 could be reduced by SB203580, indicating a role of p38MAPK activation in IL-8 production. The higher activity of beech wood log UFP in THP-1 was not due to higher uptake or endotoxin contamination. Qualitatively different protein adsorption profiles were observed, with less proteins bound to beech UFP compared to conifer UFP or DEP, which may provide higher intracellular availability of bioactive components, i.e. levoglucosan and galactosan, toward which THP-1 were more responsive compared to A549 cells. These results contribute to our understanding of particles emitted by domestic appliances and their biological effects.

  7. Ultrafine and respirable particle exposure during vehicle fire suppression.

    PubMed

    Evans, Douglas E; Fent, Kenneth W

    2015-10-01

    Vehicle fires are a common occurrence, yet few studies have reported exposures associated with burning vehicles. This article presents an assessment of firefighters' potential for ultrafine and respirable particle exposure during vehicle fire suppression training. Fires were initiated within the engine compartment and passenger cabins of three salvaged vehicles, with subsequent water suppression by fire crews. Firefighter exposures were monitored with an array of direct reading particle and air quality instruments. A flexible metallic duct and blower drew contaminants to the instrument array, positioned at a safe distance from the burning vehicles, with the duct inlet positioned at the nozzle operator's shoulder. The instruments measured the particle number, active surface area, respirable particle mass, photoelectric response, aerodynamic particle size distributions, and air quality parameters. Although vehicle fires were suppressed quickly (<10 minutes), firefighters may be exposed to short duration, high particle concentration episodes during fire suppression, which are orders of magnitude greater than the ambient background concentration. A maximum transient particle concentration of 1.21 × 10(7) particles per cm(3), 170 mg m(-3) respirable particle mass, 4700 μm(2) cm(-3) active surface area and 1400 (arbitrary units) in photoelectric response were attained throughout the series of six fires. Expressed as fifteen minute time-weighted averages, engine compartment fires averaged 5.4 × 10(4) particles per cm(3), 0.36 mg m(-3) respirable particle mass, 92 μm(2) cm(-3) active particle surface area and 29 (arbitrary units) in photoelectric response. Similarly, passenger cabin fires averaged 2.04 × 10(5) particles per cm(3), 2.7 mg m(-3) respirable particle mass, 320 μm(2) cm(-3) active particle surface area, and 34 (arbitrary units) in photoelectric response. Passenger cabin fires were a greater potential source of exposure than engine compartment fires. The

  8. Ultrafine and respirable particle exposure during vehicle fire suppression

    PubMed Central

    Fent, Kenneth W.

    2015-01-01

    Vehicle fires are a common occurrence, yet few studies have reported exposures associated with burning vehicles. This article presents an assessment of firefighters’ potential for ultrafine and respirable particle exposure during vehicle fire suppression training. Fires were initiated within the engine compartment and passenger cabins of three salvaged vehicles, with subsequent water suppression by fire crews. Firefighter exposures were monitored with an array of direct reading particle and air quality instruments. A flexible metallic duct and blower drew contaminants to the instrument array, positioned at a safe distance from the burning vehicles, with the duct inlet positioned at the nozzle operator’s shoulder. The instruments measured the particle number, active surface area, respirable particle mass, photoelectric response, aerodynamic particle size distributions, and air quality parameters. Although vehicle fires were suppressed quickly (<10 minutes), firefighters may be exposed to short duration, high particle concentration episodes during fire suppression, which are orders of magnitude greater than the ambient background concentration. A maximum transient particle concentration of 1.21 × 107 particles per cm3, 170 mg m−3 respirable particle mass, 4700 μm2 cm−3 active surface area and 1400 (arbitrary units) in photoelectric response were attained throughout the series of six fires. Expressed as fifteen minute time-weighted averages, engine compartment fires averaged 5.4 × 104 particles per cm3, 0.36 mg m−3 respirable particle mass, 92 μm2 cm−3 active particle surface area and 29 (arbitrary units) in photoelectric response. Similarly, passenger cabin fires averaged 2.04 × 105 particles per cm3, 2.7 mg m−3 respirable particle mass, 320 μm2 cm−3 active particle surface area, and 34 (arbitrary units) in photoelectric response. Passenger cabin fires were a greater potential source of exposure than engine compartment fires. The wind direction

  9. Emission of ultrafine particles from the incineration of municipal solid waste: A review

    NASA Astrophysics Data System (ADS)

    Jones, Alan M.; Harrison, Roy M.

    2016-09-01

    Ultrafine particles (diameter <100 nm) are of great topical interest because of concerns over possible enhanced toxicity relative to larger particles of the same composition. While combustion processes, and especially road traffic exhaust are a known major source of ultrafine particle emissions, relatively little is known of the magnitude of emissions from non-traffic sources. One such source is the incineration of municipal waste, and this article reviews studies carried out on the emissions from modern municipal waste incinerators. The effects of engineering controls upon particle emissions are considered, as well as the very limited information on the effects of changing waste composition. The results of measurements of incinerator flue gas, and of atmospheric sampling at ground level in the vicinity of incinerators, show that typical ultrafine particle concentrations in flue gas are broadly similar to those in urban air and that consequently, after the dispersion process dilutes incinerator exhaust with ambient air, ultrafine particle concentrations are typically indistinguishable from those that would occur in the absence of the incinerator. In some cases the ultrafine particle concentration in the flue gas may be below that in the local ambient air. This appears to be a consequence of the removal of semi-volatile vapours in the secondary combustion zone and abatement plant, and the high efficiency of fabric filters for ultrafine particle collection.

  10. Pedestrians in Traffic Environments: Ultrafine Particle Respiratory Doses

    PubMed Central

    Manigrasso, Maurizio; Natale, Claudio; Vitali, Matteo; Protano, Carmela; Avino, Pasquale

    2017-01-01

    Particulate matter has recently received more attention than other pollutants. PM10 and PM2.5 have been primarily monitored, whereas scientists are focusing their studies on finer granulometric sizes due both to their high number concentration and their high penetration efficiency into the respiratory system. The purpose of this study is to investigate the population exposure to UltraFine Particles (UFP, submicrons in general) in outdoor environments. The particle number doses deposited into the respiratory system have been compared between healthy individuals and persons affected by Chronic Obstructive Pulmonary Disease (COPD). Measurements were performed by means of Dust Track and Nanoscan analyzers. Forty minute walking trails through areas with different traffic densities in downtown Rome have been considered. Furthermore, particle respiratory doses have been estimated for persons waiting at a bus stop, near a traffic light, or along a high-traffic road, as currently occurs in a big city. Large differences have been observed between workdays and weekdays: on workdays, UFP number concentrations are much higher due to the strong contribution of vehicular exhausts. COPD-affected individuals receive greater doses than healthy individuals due to their higher respiratory rate. PMID:28282961

  11. Ultrafine particle number fluxes over and in a deciduous forest

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Barthelmie, R. J.; Larsen, S. E.; Sørensen, L. L.

    2017-01-01

    Ultrafine particles (UFP, particles with diameters (Dp) < 100 nm) play a key role in climate forcing; thus, there is interest in improved understanding of atmosphere-surface exchange of these particles. Long-term flux measurements from a deciduous forest in the Midwestern USA (taken during December 2012 to May 2014) show that although a substantial fraction of the data period indicates upward fluxes of UFP, on average, the forest is a net sink for UFP during both leaf-active and leaf-off periods. The overall mean above-canopy UFP number flux computed from this large data set is -4.90 × 106 m-2 s-1 which re-emphasizes the importance of these ecosystems to UFP removal from the atmosphere. Although there remain major challenges to accurate estimation of the UFP number flux and in drawing inferences regarding the actual surface exchange from measurements taken above the canopy, the above the canopy mean flux is shown to be downward throughout the day (except at 23.00) with largest-magnitude fluxes during the middle of the day. On average, nearly three quarters of the total UFP capture by this ecosystem occurs at the canopy. This fraction increases to 78% during the leaf-active period, but the over-storey remains dominant over the subcanopy even during the leaf-off period.

  12. The Behavior of Ultrafine Particles in the Absence and Presence of External Fields

    NASA Astrophysics Data System (ADS)

    Dutt, Meenakshi; Hancock, Bruno; Bentham, Craig; Elliott, James

    2007-03-01

    Length scales of particles and their surrounding medium strongly determines the nature of their interactions with one another and their responses to external fields. We are interested in systems of ultrafine particles (0.1 - 1.0 micron) such as volcanic ash, solid aerosols, or fine powders for pharmaceutical ihalation applications. We develop a numerical model for these systems using the Derjaguin-Muller-Toporov (DMT) adhesion theory along with the van der Waals attraction between the particles and their contact mechanical interactions. We study the dynamics of these systems in the absence and presence of gravity by controlling the particle size, and thereby, the surface properties of the particles. Finally, we explore the response of these systems to external fields by studying the evolution of the internal microstructure under contant load and shear strain.

  13. Cardiovascular Effects in Adults with Metabolic Syndrome Exposed to Concentrated Ultrafine Air Pollution Particles

    EPA Science Inventory

    RATIONALE: Epidemiologic studies report associations between ambient air pollution particulate matter (PM) and various indices of cardiopulmonary morbidity and mortality. A leading hypothesis contends that smaller ultrafine (UF) particles induce a greater physiologic response bec...

  14. Comparison of deposited surface area of airborne ultrafine particles generated from two welding processes.

    PubMed

    Gomes, J F; Albuquerque, P C; Miranda, Rosa M; Santos, Telmo G; Vieira, M T

    2012-09-01

    This article describes work performed on the assessment of the levels of airborne ultrafine particles emitted in two welding processes metal-active gas (MAG) of carbon steel and friction-stir welding (FSW) of aluminium in terms of deposited area in alveolar tract of the lung using a nanoparticle surface area monitor analyser. The obtained results showed the dependence from process parameters on emitted ultrafine particles and clearly demonstrated the presence of ultrafine particles, when compared with background levels. The obtained results showed that the process that results on the lower levels of alveolar-deposited surface area is FSW, unlike MAG. Nevertheless, all the tested processes resulted in important doses of ultrafine particles that are to be deposited in the human lung of exposed workers.

  15. Ultrafine particle removal and generation by portable air cleaners

    NASA Astrophysics Data System (ADS)

    Waring, Michael S.; Siegel, Jeffrey A.; Corsi, Richard L.

    Portable air cleaners can both remove and generate pollutants indoors. To investigate these phenomena, we conducted a two-phase investigation in a 14.75 m 3 stainless steel chamber. In the first phase, particle size-resolved (12.6-514 nm diameter) clean air delivery rates (CADR) and efficiencies were determined, as were ozone emission rates, for two high-efficiency particle arresting (HEPA) filters, one electrostatic precipitator with a fan, and two ion generators without fans. The two HEPA air cleaners had count average CADR (standard deviation) of 188 (30) and 324 (44) m 3 h -1; the electrostatic precipitator 284 (62) m 3 h -1; and the two ion generators 41 (11) and 35 (13) m 3 h -1. The electrostatic precipitator emitted ozone at a rate of 3.8±0.2 mg h -1, and the two ion generators 3.3±0.2 and 4.3±0.2 mg h -1. Ozone initiates reactions with certain unsaturated organic compounds that produce ultrafine and fine particles, carbonyls, other oxidized products, and free radicals. During the second phase, five different ion generators were operated separately in the presence of a plug-in liquid or solid air freshener, representing a strong terpene source. For air exchange rates of between 0.49 and 0.96 h -1, three ion generators acted as steady-state net particle generators in the entire measured range of 4.61-157 nm, and two generated particles in the range of approximately 10 to 39-55 nm. Terpene and aldehyde concentrations were also sampled for one ion generator, and concentrations of terpenes decreased and formaldehyde increased. Given these results, the pollutant removal benefits of ozone-generating air cleaners may be outweighed by the generation of indoor pollution.

  16. Synthesis of Strontium Ferrite Ultrafine Particles Using Microemulsion Processing.

    PubMed

    Chen, Dong-Hwang; Chen, Yuh-Yuh

    2001-04-01

    The strontium ferrite ultrafine particles have been prepared using the microemulsion processing. The mixed hydroxide precursor was obtained via the coprecipitation of Sr(2+) and Fe(3+) in a water-in-oil microemulsion of water/CTAB/n-butanol/isooctane. According to the investigation on the thermochemical properties by TGA/DTA and the phase analysis by XRD, it was shown that the precursor could yield pure strontium ferrite after calcination at 700 degrees C for 5 h while using an appropriate molar ratio of Sr/Fe in microemulsions. From TEM measurement, the diameters of the precursor and calcined particles were 3.8+/-0.7 and 50-100 nm, respectively. The magnetic properties characterized by a SQUID magnetometer showed that the saturation magnetization, remanent magnetization, coercivity, and squareness ratio were 55 emu/g, 28 emu/g, 492 Oe, and 0.51, respectively. The magnetization was also observed to increase with the decrease of temperature at 5-400 K. Compared with those reported earlier, the quite low coercivity implies the potential application of final product in the high-density perpendicular recording media. Copyright 2001 Academic Press.

  17. Outdoor ultrafine particle concentrations in front of fast food restaurants.

    PubMed

    Vert, Cristina; Meliefste, Kees; Hoek, Gerard

    2016-01-01

    Ultrafine particles (UFPs) have been associated with negative effects on human health. Emissions from motor vehicles are the principal source of UFPs in urban air. A study in Vancouver suggested that UFP concentrations were related to density of fast food restaurants near the monitoring sites. A previous monitoring campaign could not separate the contribution of restaurants from road traffic. The main goal of this study has been the quantification of fast food restaurants' contribution to outdoor UFP concentrations. A portable particle number counter (DiscMini) has been used to carry out mobile monitoring in a largely pedestrianized area in the city center of Utrecht. A fixed route passing 17 fast food restaurants was followed on 8 days. UFP concentrations in front of the restaurants were 1.61 times higher than in a nearby square without any local sources used as control area and 1.22 times higher compared with all measurements conducted in between the restaurants. Adjustment for other sources such as passing mopeds, smokers or candles did not explain the increase. In conclusion, fast food restaurants result in significant increases in outdoor UFP concentrations in front of the restaurant.

  18. Characterization of individual fine and ultrafine particles with a real-time single particle mass spectrometer

    NASA Astrophysics Data System (ADS)

    Reinard, Melissa S.

    2008-10-01

    Designed to analyze aerosols in ambient settings, the Real-Time Single Particle Mass Spectrometer (RSMS) provides a highly time-resolved measurement of the physical and chemical properties of individual fine (<2.5 mum dia.) and ultrafine (<0.1 mum dia.) particles. Understanding aerosols within this size range is crucial as these particles greatly impact both human health and the environment. Data collected by RSMS can be used identify particle sources and atmospheric processes. RSMS was deployed to Wilmington, DE during 2005-2006 as part of E-DATAS (Enhanced Delaware Air Toxics Assessment Study), a collaboration with the Delaware Department of Natural Resources (DNREC), the Environmental Protection Agency (EPA) and Duke University. Mass spectra acquired by RSMS were compared to a Scanning Mobility Particle Sizer (SMPS) to give a quantitative estimate of the chemical composition of PM1.0 (particulate matter <1.0 mum dia.) impacting the city. A method to collect and analyze particles directly from emission stacks of industrial facilities was developed to help identify sources of PM. Single particle mass spectrometry, in general, has remained primarily a qualitative technique due to several instrumental limitations which affect the data. First, the shot-to-shot variation in the laser pulse caused inconsistencies between the mass spectra of particles with the same composition. To determine whether this variation was systematic or random, the covariance between ions was calculated for laboratory generated aerosols. Second, RSMS was found to be highly sensitive to specific chemical species such as ammonium nitrate and transition/alkali metals. When these compounds are present in a particle they dominate the mass spectra and dwarf other the signal from other components to the baseline. To explore this bias, data collected by RSMS in Wilmington, DE was compared to data also collected in Wilmington by the quantitative NanoAerosol Mass Spectrometer (NAMS). Finally, a light

  19. The Effect of Ventilation, Age, and Asthmatic Condition on Ultrafine Particle Deposition in Children

    PubMed Central

    Olvera, Hector A.; Perez, Daniel; Clague, Juan W.; Cheng, Yung-Sung; Li, Wen-Whai; Amaya, Maria A.; Burchiel, Scott W.; Berwick, Marianne; Pingitore, Nicholas E.

    2012-01-01

    Ultrafine particles (UFPs) contribute to health risks associated with air pollution, especially respiratory disease in children. Nonetheless, experimental data on UFP deposition in asthmatic children has been minimal. In this study, the effect of ventilation, developing respiratory physiology, and asthmatic condition on the deposition efficiency of ultrafine particles in children was explored. Deposited fractions of UFP (10–200 nm) were determined in 9 asthmatic children, 8 nonasthmatic children, and 5 nonasthmatic adults. Deposition efficiencies in adults served as reference of fully developed respiratory physiologies. A validated deposition model was employed as an auxiliary tool to assess the independent effect of varying ventilation on deposition. Asthmatic conditions were confirmed via pre-and post-bronchodilator spirometry. Subjects were exposed to a hygroscopic aerosol with number geometric mean diameter of 27–31 nm, geometric standard deviation of 1.8–2.0, and concentration of 1.2 × 106 particles cm−3. Exposure was through a silicone mouthpiece. Total deposited fraction (TDF) and normalized deposition rate were 50% and 32% higher in children than in adults. Accounting for tidal volume and age variation, TDF was 21% higher in asthmatic than in non-asthmatic children. The higher health risks of air pollution exposure observed in children and asthmatics might be augmented by their susceptibility to higher dosages of UFP. PMID:22848818

  20. Ultrafine particle size as a tracer for aircraft turbine emissions.

    PubMed

    Riley, Erin A; Gould, Timothy; Hartin, Kris; Fruin, Scott A; Simpson, Christopher D; Yost, Michael G; Larson, Timothy

    2016-08-01

    Ultrafine particle number (UFPN) and size distributions, black carbon, and nitrogen dioxide concentrations were measured downwind of two of the busiest airports in the world, Los Angeles International Airport (LAX) and Hartsfield-Jackson International Airport (ATL - Atlanta, GA) using a mobile monitoring platform. Transects were located between 5 km and 10 km from the ATL and LAX airports. In addition, measurements were taken at 43 additional urban neighborhood locations in each city and on freeways. We found a 3-5 fold increase in UFPN concentrations in transects under the landing approach path to both airports relative to surrounding urban areas with similar ground traffic characteristics. The latter UFPN concentrations measured were distinct in size distributional properties from both freeways and across urban neighborhoods, clearly indicating different sources. Elevated concentrations of Black Carbon (BC) and NO2 were also observed on airport transects, and the corresponding pattern of elevated BC was consistent with the observed excess UFPN concentrations relative to other urban locations.

  1. Ultrafine particle air pollution inside diesel-propelled passenger trains.

    PubMed

    Abramesko, Victoria; Tartakovsky, Leonid

    2017-04-05

    Locomotives with diesel engines are used worldwide and are an important source of air pollution. Pollutant emissions by locomotive engines affect the air quality inside passenger trains. This study is aimed at investigating ultrafine particle (UFP) air pollution inside passenger trains and providing a basis for assessing passenger exposure to this pollutant. The concentrations of UFPs inside the carriages of push-pull trains are dramatically higher when the train operates in pull mode. This clearly shows that locomotive engine emissions are a dominant factor in train passengers' exposure to UFPs. The highest levels of UFP air pollution are observed inside the carriages of pull trains close to the locomotive. In push mode, the UFP number concentrations were lower by factors of 2.6-43 (depending on the carriage type) compared to pull mode. The UFP concentrations are substantially lower in diesel multiple-unit trains than in trains operating in pull mode. A significant influence of the train movement regime on the UFP NC inside a carriage is observed.

  2. Ultrafine particle size as a tracer for aircraft turbine emissions

    NASA Astrophysics Data System (ADS)

    Riley, Erin A.; Gould, Timothy; Hartin, Kris; Fruin, Scott A.; Simpson, Christopher D.; Yost, Michael G.; Larson, Timothy

    2016-08-01

    Ultrafine particle number (UFPN) and size distributions, black carbon, and nitrogen dioxide concentrations were measured downwind of two of the busiest airports in the world, Los Angeles International Airport (LAX) and Hartsfield-Jackson International Airport (ATL - Atlanta, GA) using a mobile monitoring platform. Transects were located between 5 km and 10 km from the ATL and LAX airports. In addition, measurements were taken at 43 additional urban neighborhood locations in each city and on freeways. We found a 3-5 fold increase in UFPN concentrations in transects under the landing approach path to both airports relative to surrounding urban areas with similar ground traffic characteristics. The latter UFPN concentrations measured were distinct in size distributional properties from both freeways and across urban neighborhoods, clearly indicating different sources. Elevated concentrations of Black Carbon (BC) and NO2 were also observed on airport transects, and the corresponding pattern of elevated BC was consistent with the observed excess UFPN concentrations relative to other urban locations.

  3. ULTRAFINE PARTICLE DEPOSITION IN HEALTHY SUBJECTS VS. PATIENTS WTH COPD

    EPA Science Inventory

    Individuals affected with chronic obstructive pulmonary disease (COPD) have increased susceptibility to adverse health effects from exposure to particulate air pollution. The dosimetry of ultrafine aerosols (diameter # 0.1 :m) is not well characterized in the healthy or diseas...

  4. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period was devoted to experimental design and fabrication tasks.

  5. ULTRAFINE PARTICLE CONCENTRATIONS NEAR FREEWAYS AT NIGHT OR EARLY MORNING UNDER CALM WEATHER CONDITIONS

    EPA Science Inventory

    There is evidence that ultrafine (UF) particles dominate the number concentrations in close proximity to the roadway. The UF particles are also known to be more toxic than larger sizes of PM on an equal mass basis. In this work, UF particle number concentrations were measured u...

  6. ENHANCED TOXICITY OF CHARGED CARBON NANOTUBES AND ULTRAFINE CARBON BLACK PARTICLES

    EPA Science Inventory

    Man-made carbonaceous nano-particles such as single and multi-walled carbon nano-tubes (CNT) and ultra-fine carbon black (UFCB) particles are finding increasing applications in industry, but their potential toxic effects is of concern. In aqueous media, these particles cluster in...

  7. What does respirator certification tell us about filtration of ultrafine particles?

    PubMed

    Eninger, Robert M; Honda, Takeshi; Reponen, Tiina; McKay, Roy; Grinshpun, Sergey A

    2008-05-01

    Recent interest in exposures to ultrafine particles (less than 100 nm) in both environmental and occupational settings led the authors to question whether the protocols used to certify respirator filters provide adequate attention to ultrafine aerosols. The authors reviewed the particle size distribution of challenge aerosols and evaluated the aerosol measurement method currently employed in the National Institute for Occupational Safety and Health (NIOSH) particulate respirator certification protocol for its ability to measure the contribution of ultrafine particles to filter penetration. Also considered were the differences between mechanical and electrically charged (electret) filters in light of the most penetrating particle size. It was found that the sodium chloride (NaCl) and dioctylphthalate (DOP) aerosols currently used in respirator certification tests contain a significant fraction of particles in the ultrafine region. However, the photometric method deployed in the certification test is not capable of adequately measuring light scatter of particles below approximately 100 nm in diameter. Specifically, 68% (by count) and 8% (by mass) of the challenge NaCl aerosol particles and 10% (by count) and 0.3% (by mass) of the DOP particles below 100 nm do not significantly contribute to the filter penetration measurement. In addition, the most penetrating particle size for electret filters likely occurs at 100 nm or less under test conditions similar to those used in filter certification. The authors conclude, therefore, that the existing NIOSH certification protocol may not represent a worst-case assessment for electret filters because it has limited ability to determine the contribution of ultrafine aerosols, which include the most penetrating particle size for electret filters. Possible strategies to assess ultrafine particle penetration in the certification protocol are discussed.

  8. Ultrafine particle generation by high-velocity impact of metal projectiles

    NASA Astrophysics Data System (ADS)

    Stabile, L.; Iannitti, G.; Vigo, P.; Ruggiero, A.; Russi, A.; Buonanno, G.

    2014-05-01

    Ultrafine particle generation through mechanical processes was not carefully deepened so far, even if it could be related to the human health-based researches. In particular, the evaluation of ultrafine particles produced in battlefield scenarios can be useful to quantify the exposure of soldiers to particles carrying toxic heavy metals. In the present work ultrafine particle generation during high-velocity impact of metal projectiles was deepened performing symmetrical high velocity Taylor impacts of copper cylinder tests (Rod-on-Rod tests) by means of a gas-gun facility. Particle number distributions and total concentrations were measured through one-second-time resolution instruments in a chamber where impact events at different velocities were performed. Particle number generation per impact was also evaluated. Particle concentrations in the 106 part. cm-3 range were measured corresponding to particle generations higher than 1012 particles per impact, then comparable to those typical of combustion sources. Particle number distribution showed a unimodal distribution with a 10 nm mode. Summarizing, the performed experimental campaign revealed an extremely high generation of ultrafine particles from mechanical processes.

  9. Ambient Ultrafine Particle Ingestion Alters Gut Microbiota in Association with Increased Atherogenic Lipid Metabolites

    PubMed Central

    Li, Rongsong; Yang, Jieping; Saffari, Arian; Jacobs, Jonathan; Baek, Kyung In; Hough, Greg; Larauche, Muriel H.; Ma, Jianguo; Jen, Nelson; Moussaoui, Nabila; Zhou, Bill; Kang, Hanul; Reddy, Srinivasa; Henning, Susanne M.; Campen, Matthew J.; Pisegna, Joseph; Li, Zhaoping; Fogelman, Alan M.; Sioutas, Constantinos; Navab, Mohamad; Hsiai, Tzung K.

    2017-01-01

    Ambient particulate matter (PM) exposure is associated with atherosclerosis and inflammatory bowel disease. Ultrafine particles (UFP, dp < 0.1–0.2 μm) are redox active components of PM. We hypothesized that orally ingested UFP promoted atherogenic lipid metabolites in both the intestine and plasma via altered gut microbiota composition. Low density lipoprotein receptor-null (Ldlr−/−) mice on a high-fat diet were orally administered with vehicle control or UFP (40 μg/mouse/day) for 3 days a week. After 10 weeks, UFP ingested mice developed macrophage and neutrophil infiltration in the intestinal villi, accompanied by elevated cholesterol but reduced coprostanol levels in the cecum, as well as elevated atherogenic lysophosphatidylcholine (LPC 18:1) and lysophosphatidic acids (LPAs) in the intestine and plasma. At the phylum level, Principle Component Analysis revealed significant segregation of microbiota compositions which was validated by Beta diversity analysis. UFP-exposed mice developed increased abundance in Verrocomicrobia but decreased Actinobacteria, Cyanobacteria, and Firmicutes as well as a reduced diversity in microbiome. Spearman’s analysis negatively correlated Actinobacteria with cecal cholesterol, intestinal and plasma LPC18:1, and Firmicutes and Cyanobacteria with plasma LPC 18:1. Thus, ultrafine particles ingestion alters gut microbiota composition, accompanied by increased atherogenic lipid metabolites. These findings implicate the gut-vascular axis in a atherosclerosis model. PMID:28211537

  10. A new approach for on-line measurements of the chemistry of individual ultrafine particles

    NASA Astrophysics Data System (ADS)

    Zauscher, M. D.; Lewis, G. S.; Hering, S. V.; Prather, K. A.

    2009-12-01

    Ultrafine aerosol particles, those with diameters less than 100nm, are abundant in the atmosphere and play a crucial role in climate through cloud formation and have a greater effect on human health than larger particles. The chemistry of ultrafine particles helps determine whether they will act as cloud condensation nuclei (CCN) as well as how they will affect human health. However, it is difficult to study the chemistry of ultrafine particles due to their low mass and small size for optical detection. Typically, long collection times are required to collect ultrafine particles onto substrates, leading to loss of temporal information and individual particle chemistry and source information. Single particle mass spectrometers that rely on optical detection of particles for subsequent chemical analysis cannot effectively analyze ultrafine particles. Growth of particles through condensation has been used in various sizing (i.e. condensation particle counter (CPC), cloud condensation nuclei counter (CCNc)), as well as chemical (i.e. particle into liquid system (PILS) and condensation growth and impaction system (C-GIS)) instruments. In order to study ultrafine particles, we couple a laminar flow, water condensation growth tube (GT) with an aerodynamic focusing lens aerosol time-of-flight mass spectrometer (ATOFMS). The GT used here is similar in principle to the water-based CPC. The particles are exposed to a region of high supersaturation where they grow in size by water vapor condensation. We have coupled this GT to a single particle mass spectrometry ATOFMS system. Using this combined approach, we are able to detect polystyrene latex spheres (PSLs) as small as 38nm compared to the lower size limit of 90 nm of the ATOFMS without the GT. A series of inorganic and organic chemical standards representative of ambient particles show that by evaporating the particles between the GT and ATOFMS, there is little change in the chemistry of the particles that have undergone

  11. The role of organic condensation on ultrafine particle growth during nucleation events

    NASA Astrophysics Data System (ADS)

    Patoulias, D.; Fountoukis, C.; Riipinen, I.; Pandis, S. N.

    2015-06-01

    A new aerosol dynamics model (DMANx) has been developed that simulates aerosol size/composition distribution and includes the condensation of organic vapors on nanoparticles through the implementation of the recently developed volatility basis set framework. Simulations were performed for Hyytiälä (Finland) and Finokalia (Greece), two locations with different organic sources where detailed measurements were available to constrain the new model. We investigate the effect of condensation of organics and chemical aging reactions of secondary organic aerosol (SOA) precursors on ultrafine particle growth and particle number concentration during a typical springtime nucleation event in both locations. This work highlights the importance of the pathways of oxidation of biogenic volatile organic compounds and the production of extremely low volatility organics. At Hyytiälä, organic condensation dominates the growth process of new particles. The low-volatility SOA contributes to particle growth during the early growth stage, but after a few hours most of the growth is due to semi-volatile SOA. At Finokalia, simulations show that organics have a complementary role in new particle growth, contributing 45% to the total mass of new particles. Condensation of organics increases the number concentration of particles that can act as CCN (cloud condensation nuclei) (N100) by 13% at Finokalia and 25% at Hyytiälä during a typical spring day with nucleation. The sensitivity of our results to the surface tension used is discussed.

  12. Physicochemical characteristics and occupational exposure to coarse, fine and ultrafine particles during building refurbishment activities

    NASA Astrophysics Data System (ADS)

    Azarmi, Farhad; Kumar, Prashant; Mulheron, Mike; Colaux, Julien L.; Jeynes, Chris; Adhami, Siavash; Watts, John F.

    2015-08-01

    Understanding of the emissions of coarse (PM10 ≤10 μm), fine (PM2.5 ≤2.5 μm) and ultrafine particles (UFP <100 nm) from refurbishment activities and their dispersion into the nearby environment is of primary importance for developing efficient risk assessment and management strategies in the construction and demolition industry. This study investigates the release, occupational exposure and physicochemical properties of particulate matter, including UFPs, from over 20 different refurbishment activities occurring at an operational building site. Particles were measured in the 5-10,000-nm-size range using a fast response differential mobility spectrometer and a GRIMM particle spectrometer for 55 h over 8 days. The UFPs were found to account for >90 % of the total particle number concentrations and <10 % of the total mass concentrations released during the recorded activities. The highest UFP concentrations were 4860, 740, 650 and 500 times above the background value during wall-chasing, drilling, cementing and general demolition activities, respectively. Scanning electron microscopy, X-ray photoelectron spectroscopy and ion beam analysis were used to identify physicochemical characteristics of particles and attribute them to probable sources considering the size and the nature of the particles. The results confirm that refurbishment activities produce significant levels (both number and mass) of airborne particles, indicating a need to develop appropriate regulations for the control of occupational exposure of operatives undertaking building refurbishment.

  13. DEPOSITION DISTRIBUTION OF NANO AND ULTRAFINE PARTICLES IN HUMAN LUNGS DURING CONTROLLED MOUTH BREATHING

    EPA Science Inventory

    Nano and ultrafine particles are abundant in the atmosphere and the level of human exposure to these tiny particles is expected to increase markedly as industrial activities increase manufacturing nano-sized materials. Exposure-dose relationships and site-specific internal dose a...

  14. A mechanism for the production of ultrafine particles from concrete fracture.

    PubMed

    Jabbour, Nassib; Rohan Jayaratne, E; Johnson, Graham R; Alroe, Joel; Uhde, Erik; Salthammer, Tunga; Cravigan, Luke; Faghihi, Ehsan Majd; Kumar, Prashant; Morawska, Lidia

    2017-03-01

    While the crushing of concrete gives rise to large quantities of coarse dust, it is not widely recognized that this process also emits significant quantities of ultrafine particles. These particles impact not just the environments within construction activities but those in entire urban areas. The origin of these ultrafine particles is uncertain, as existing theories do not support their production by mechanical processes. We propose a hypothesis for this observation based on the volatilisation of materials at the concrete fracture interface. The results from this study confirm that mechanical methods can produce ultrafine particles (UFP) from concrete, and that the particles are volatile. The ultrafine mode was only observed during concrete fracture, producing particle size distributions with average count median diameters of 27, 39 and 49 nm for the three tested concrete samples. Further volatility measurements found that the particles were highly volatile, showing between 60 and 95% reduction in the volume fraction remaining by 125 °C. An analysis of the volatile fraction remaining found that different volatile material is responsible for the production of particles between the samples.

  15. OXIDATIVE STRESS AND LIPID MEDIATORS INDUCED IN ALVEOLAR MACHROPHAGES BY ULTRAFINE PARTICLES

    EPA Science Inventory

    In ambient aerosols, ultrafine particles (UFP) and their agglomerates are considered to be major factors contributing to adverse health effects. Reactivity of agglomerated UFP of elemental carbon (EC), Printex 90, Printex G, and diesel exhaust particles (DEP) was evaluated by the...

  16. UP-REGULATION OF TISSUE FACTOR IN HUMAN PULMONARY ARTERY ENDOTHELIAL CELLS AFTER ULTRAFINE PARTICLE EXPOSURE

    EPA Science Inventory

    Background: Epidemiology studies have linked exposure to pollutant particles to

    increased cardiovascular mortality and morbidity, but the mechanisms remain unknown.

    Objectives: We tested the hypothesis that the ultrafine fraction of ambient pollutant

    particle...

  17. Association of particulate air pollution and acute mortality: involvement of ultrafine particles?

    NASA Technical Reports Server (NTRS)

    Oberdorster, G.; Gelein, R. M.; Ferin, J.; Weiss, B.; Clarkson, T. W. (Principal Investigator)

    1995-01-01

    Recent epidemiological studies show an association between particulate air pollution and acute mortality and morbidity down to ambient particle concentrations below 100 micrograms/m3. Whether this association also implies a causality between acute health effects and particle exposure at these low levels is unclear at this time; no mechanism is known that would explain such dramatic effects of low ambient particle concentrations. Based on results of our past and most recent inhalation studies with ultrafine particles in rats, we propose that such particles, that is, particles below approximately 50 nm in diameter, may contribute to the observed increased mortality and morbidity In the past we demonstrated that inhalation of highly insoluble particles of low intrinsic toxicity, such as TiO2, results in significantly increased pulmonary inflammatory responses when their size is in the ultrafine particle range, approximately 20 nm in diameter. However, these effects were not of an acute nature and occurred only after prolonged inhalation exposure of the aggregated ultrafine particles at concentrations in the milligrams per cubic meter range. In contrast, in the course of our most recent studies with thermodegradation products of polytetrafluoroethylene (PTFE) we found that freshly generated PTFE fumes containing singlet ultrafine particles (median diameter 26 nm) were highly toxic to rats at inhaled concentrations of 0.7-1.0 x 10(6) particles/cm3, resulting in acute hemorrhagic pulmonary inflammation and death after 10-30 min of exposure. We also found that work performance of the rats in a running wheel was severely affected by PTFE fume exposure. These results confirm reports from other laboratories of the highly toxic nature of PTFE fumes, which cannot be attributed to gas-phase components of these fumes such as HF, carbonylfluoride, or perfluoroisobutylene, or to reactive radicals. The calculated mass concentration of the inhaled ultrafine PTFE particles in our

  18. Purification of single-wall carbon nanotubes by using ultrafine gold particles

    NASA Astrophysics Data System (ADS)

    Nihey, Fumiyuki; Mizoguti, Eiji; Yudasaka, Masako; Iijima, Sumio; Ichihashi, Toshinari; Nakamura, Kazuo

    2000-03-01

    The purification of single-wall carbon nanotubes (SWNTs) is needed to enable detailed characterization and some application of this material. We report a purification method utilizing ultrafine gold particles as catalysts to selectively oxidize carbonaceous impurities in SWNT soot. The ultrafine gold particles with a diameter of 20 nm were dispersed in the soot in combination with benzalkonium chloride as surfactant. Thermogravimetric analyses and electron microscopy observations revealed that oxidation occured at about 330^circC for carbonaceous impurities and at about 410^circC for SWNTs. This selective oxidation enabled us to purify SWNTs and make the quantitative analyses of SWNTs.

  19. Pulmonary toxicity study in rats with three forms of ultrafine-TiO2 particles: differential responses related to surface properties.

    PubMed

    Warheit, David B; Webb, Thomas R; Reed, Kenneth L; Frerichs, Scott; Sayes, Christie M

    2007-01-25

    Surface properties are critical to assess effects of ultrafine-TiO(2) particles. The aim of this study was to assess lung toxicity in rats of newly developed, well characterized, ultrafine-TiO(2) particles and compare them to TiO(2) samples in two different size ranges and surface modifications. Groups of rats were intratracheally instilled with doses of 1 or 5mg/kg of either two ultrafine rutile TiO(2) particles (uf-1 or uf-2); rutile R-100 fine-TiO(2) (F-1); 80/20 anatase/rutile P25 ultrafine-TiO(2) (uf-3); or alpha-quartz particles. Phosphate-buffered saline (PBS) solution instilled rats served as vehicle controls. Following exposures, the lungs of PBS and particle-exposed rats were evaluated for bronchoalveolar lavage (BAL) fluid inflammatory markers, cell proliferation, and by histopathology at post-instillation time points of 24h, 1 week, 1 and 3 months. The ranking of lung inflammation/cytotoxicity/cell proliferation and histopathological responses was quartz>uf-3>F-1=uf-1=uf-2. Exposures to quartz and to a lesser degree, uf-3 anatase/rutile TiO(2) particles produced pulmonary inflammation, cytotoxicity and adverse lung tissue effects. In contrast, exposures to F-1 fine-TiO(2) particles or to uf-1/uf-2 ultrafine-TiO(2) particle-types produced transient inflammation. We conclude that differences in responses to anatase/rutile uf-3 TiO(2) particles versus the rutile uf-1 and uf-2 TiO(2) particles could be related to crystal structure, inherent pH of the particles, or surface chemical reactivity. Thus, based on these results, inhaled rutile ultrafine-TiO(2) particles are expected to have a low risk potential for producing adverse pulmonary health effects. Finally, the results demonstrate that exposures to ultrafine-TiO(2) particle-types can produce differential pulmonary effects, based upon their composition, and crystal structure. Thus, the lung toxicity of anatase/rutile uf-3 should not be viewed as representative for all ultrafine-TiO(2) particle-types.

  20. Aggregates of ultrafine particles impair phagocytosis of microorganisms by human alveolar macrophages.

    PubMed

    Lundborg, Margot; Dahlén, Sven-Erik; Johard, Urban; Gerde, Per; Jarstrand, Connie; Camner, Per; Låstbom, Lena

    2006-02-01

    We investigated whether exposure of alveolar macrophages to aggregates of ultrafine carbon particles affected subsequent phagocytosis of microorganisms. Human alveolar macrophages were obtained by bronchoalveolar lavage and exposed to aggregates of ultrafine carbon particles or diesel exhaust particles (DEP) for 20 h before measurements of phagocytosis. The particle loads were estimated to be comparable to those of air pollution exposure with established health effects in humans. Phagocytotic activity was measured as attachment and ingestion of four different test particles (amorphous silica particles, yeast cells from Candida albicans, and Cryptococcus neoformans opsonized with specific IgG or fresh serum) that bind to scavenger, mannose, Fc, and complement receptors, respectively. Carbon preloading significantly impaired the attachment and ingestion process (P<0.01) for all particles, except for yeast cells from C. neoformans opsonized with specific IgG. On the average, the accumulated attachment decreased by 30% and the ingested fraction decreased by 10%. Loading of alveolar macrophages with either aggregates of ultrafine DEP or carbon particles impaired the phagocytosis of silica test particles in a similar way. Exposure of human alveolar macrophages to aggregates of carbon or DEP, in concentrations relevant to human environmental exposures, caused significant impairment of phagocytosis of silica particles and microorganisms. The inhibitory effect on particle phagocytosis mediated by four different receptors suggests that air pollution particles cause a general inhibition of macrophage phagocytosis. Such an effect may contribute to increased susceptibility to infections and, for example, result in more exacerbations of asthma and chronic obstructive pulmonary disease.

  1. A Micro Aerosol Sensor for the Measurement of Airborne Ultrafine Particles

    PubMed Central

    Zhang, Chao; Zhu, Rong; Yang, Wenming

    2016-01-01

    Particle number concentration and particle size are the two key parameters used to characterize exposure to airborne nanoparticles or ultrafine particles that have attracted the most attention. This paper proposes a simple micro aerosol sensor for detecting the number concentration and particle size of ultrafine particles with diameters from 50 to 253 nm based on electrical diffusion charging. The sensor is composed of a micro channel and a couple of planar electrodes printed on two circuit boards assembled in parallel, which thus integrate charging, precipitating and measurement elements into one chip, the overall size of which is 98 × 38 × 25 mm3. The experiment results demonstrate that the sensor is useful for measuring monodisperse aerosol particles with number concentrations from 300 to 2.5 × 104 /cm3 and particle sizes from 50 to 253 nm. The aerosol sensor has a simple structure and small size, which is favorable for use in handheld devices. PMID:26999156

  2. Water-based condensation particle counters for environmental monitoring of ultrafine particles.

    PubMed

    Liu, Wei; Kaufman, Stanley L; Osmondson, Brian L; Sem, Gilmore J; Quant, Frederick R; Oberreit, Derek R

    2006-04-01

    TSI Inc. (Shoreview, MN) has introduced three new water-based condensation particle counters (WCPCS) that were designed to detect airborne particles larger than 2.5 nm (model 3786), 5 nm (model 3785), and either 10 or 20 nm (model 3782). These WCPCs are well suited for real-time, environmental monitoring of number concentration of airborne ultrafine particles. Their unique design incorporates the use of water as the working fluid instead of alcohol. Water is odor free, readily available, and eliminates the problem of water condensation and absorption into alcohol working fluids during operation in humid environments. In this study, the performance of three TSI WCPCs was characterized for several aerosol compositions, including sucrose, salt (NaCl), dioctyl sebacate (DOS), dioctyl phthalate (DOP), emery oil (poly-alpha-olefin), silver, impurity residue particles, and ambient aerosol particles. All particles were size selected using a nano differential mobility analyzer (nano-DMA; model 3085, TSI Inc.) to create monodisperse challenge aerosols. The challenge aerosol was mixed uniformly with clean makeup flow and split into a WCPC and a reference instrument to determine the counting efficiency of the WCPC. For the model 3785 WCPC, the D50 (i.e., the particle diameter with 50% counting efficiency) was determined to be 3.1 nm for salt particles, 4.7 nm for sucrose and ambient particles, 5.6 nm for silver particles, and >50 nm for ultrapure oil particles. The sensitivity to oil droplets increased dramatically (D50 < 10 nm) when the oil was slightly contaminated. The D50 of model 3786 ultrafine water-based CPC (UWCPC) was 2.4 nm for impurity residue particles. The D50 of the model 3782 WCPC was 10.8 (with a nominal setting of 10 nm) or 19.8 nm (with a nominal setting of 20 nm) for sucrose particles. All three WCPCs have response times of less than 2 or 3 sec and are therefore able to detect fast-changing events.

  3. Variability in exposure to ambient ultrafine particles in urban schools: Comparative assessment between Australia and Spain.

    PubMed

    Mazaheri, Mandana; Reche, Cristina; Rivas, Ioar; Crilley, Leigh R; Álvarez-Pedrerol, Mar; Viana, Mar; Tobias, Aurelio; Alastuey, Andrés; Sunyer, Jordi; Querol, Xavier; Morawska, Lidia

    2016-03-01

    Ambient ultrafine particle number concentrations (PNC) have inhomogeneous spatio-temporal distributions and depend on a number of different urban factors, including background conditions and distant sources. This paper quantitatively compares exposure to ambient ultrafine particles at urban schools in two cities in developed countries, with high insolation climatic conditions, namely Brisbane (Australia) and Barcelona (Spain). The analysis used comprehensive indoor and outdoor air quality measurements at 25 schools in Brisbane and 39 schools in Barcelona. PNC modes were analysed with respect to ambient temperature, land use and urban characteristics, combined with the measured elemental carbon concentrations, NOx (Brisbane) and NO2 (Barcelona). The trends and modes of the quantified weekday average daily cycles of ambient PNC exhibited significant differences between the two cities. PNC increases were observed during traffic rush hours in both cases. However, the mid-day peak was dominant in Brisbane schools and had the highest contribution to total PNC for both indoors and outdoors. In Barcelona, the contribution from traffic was highest for ambient PNC, while the mid-day peak had a slightly higher contribution for indoor concentrations. Analysis of the relationships between PNC and land use characteristics in Barcelona schools showed a moderate correlation with the percentage of road network area and an anti-correlation with the percentage of green area. No statistically significant correlations were found for Brisbane. Overall, despite many similarities between the two cities, school-based exposure patterns were different. The main source of ambient PNC at schools was shown to be traffic in Barcelona and mid-day new particle formation in Brisbane. The mid-day PNC peak in Brisbane could have been driven by the combined effect of background and meteorological conditions, as well as other local/distant sources. The results have implications for urban development

  4. SEPARATION OF FISCHER-TROPSCH WAX PRODUCTS FROM ULTRAFINE IRON CATALYST PARTICLES

    SciTech Connect

    James K. Neathery; Gary Jacobs; Burtron H. Davis

    2004-03-31

    In this reporting period, a fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of production since the reaction is highly exothermic. Consequently, heavy wax products must be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase FTS. The separation problem is further compounded by catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. Existing pilot-scale equipment was modified to include a filtration test apparatus. After undergoing an extensive plant shakedown period, filtration tests with cross-flow filter modules using simulant FTS wax slurry were conducted. The focus of these early tests was to find adequate mixtures of polyethylene wax to simulate FTS wax. Catalyst particle size analysis techniques were also developed. Initial analyses of the slurry and filter permeate particles will be used by the research team to design improved filter media and cleaning strategies.

  5. Ultrafine particle emission characteristics of diesel engine by on-board and test bench measurement.

    PubMed

    Huang, Cheng; Lou, Diming; Hu, Zhiyuan; Tan, Piqiang; Yao, Di; Hu, Wei; Li, Peng; Ren, Jin; Chen, Changhong

    2012-01-01

    This study investigated the emission characteristics of ultrafine particles based on test bench and on-board measurements. The bench test results showed the ultrafine particle number concentration of the diesel engine to be in the range of (0.56-8.35) x 10(8) cm(-3). The on-board measurement results illustrated that the ultrafine particles were strongly correlated with changes in real-world driving cycles. The particle number concentration was down to 2.0 x 10(6) cm(-3) and 2.7 x 10(7) cm(-3) under decelerating and idling operations and as high as 5.0 x 10(8) cm(-3) under accelerating operation. It was also indicated that the particle number measured by the two methods increased with the growth of engine load at each engine speed in both cases. The particle number presented a "U" shaped distribution with changing speed at high engine load conditions, which implies that the particle number will reach its lowest level at medium engine speeds. The particle sizes of both measurements showed single mode distributions. The peak of particle size was located at about 50-80 nm in the accumulation mode particle range. Nucleation mode particles will significantly increase at low engine load operations like idling and decelerating caused by the high concentration of unburned organic compounds.

  6. [Research on NEDC ultrafine particle emission characters of a port fuel injection gasoline car].

    PubMed

    Hu, Zhi-Yuan; Li, Jin; Tan, Pi-Qiang; Lou, Di-Ming

    2012-12-01

    A Santana gasoline car with multi-port fuel injection (PFI) system was used as the research prototype and an engine exhaust particle sizer (EEPS) was employed to investigate the exhaust ultrafine particle number and size distribution characters of the tested vehicle in new European driving cycle (NEDC). The tested results showed that the vehicle's nuclear particle number, accumulation particle number, as well as the total particle number emission increased when the car drove in accelerated passage, and the vehicle's particle number emission was high during the first 40 seconds after test started and when the speed was over 90 km x h(-1) in extra urban driving cycle (EUDC) in NEDC. The ultrafine particle distribution of the whole NEDC showed a single peak logarithmic distribution, with diameters of the peak particle number emission ranging from 10 nm to 30 nm, and the geometric mean diameter was 24 nm. The ultrafine particle distribution of the urban driving cycle named by the economic commission for Europe (ECE) e. g. ECE I, ECE II - IV, the extra urban driving cycle e. g. EUDC, and the idling, constant speed, acceleration, deceleration operation conditions of NEDC all showed a single peak logarithmic distribution, also with particle diameters of the peak particle number emission ranging from 10 nm to 30 nm, and the geometric mean diameters of different driving cycle and different driving mode were from 14 nm to 42 nm. Therefore, the ultrafine particle emissions of the tested PFI gasoline car were mainly consisted of nuclear mode particles with a diameter of less than 50 nm.

  7. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    SciTech Connect

    James K. Neathery; Gary Jacobs; Amitava Sarkar; Burtron H. Davis

    2006-03-31

    The morphological and chemical nature of ultrafine iron catalyst particles (3-5 nm diameters) during activation/FTS was studied by HRTEM, EELS, and Moessbauer spectroscopy. With the progress of FTS, the carbide re-oxidized to magnetite and catalyst activity gradually decreased. The growth of oxide phase continued and average particle size also increased simultaneously. The phase transformation occurred in a ''growing oxide core'' manner with different nano-zones. The nano-range carbide particles did not show fragmentation or attrition as generally observed in micrometer range particles. Nevertheless, when the dimension of particles reached the micrometer range, the crystalline carbide phase appeared to be sprouted on the surface of magnetite single crystal. In the previous reporting period, a design and operating philosophy was developed for an integrated wax filtration system for a 4 liter slurry bubble column reactor to be used in Phase II of this research program. During the current reporting period, we have started construction of the new filtration system and began modifications to the 4 liter slurry bubble column reactor (SBCR) reactor. The system will utilize a primary wax separation device followed by a Pall Accusep or Membralox ceramic cross-flow membrane. As of this writing, the unit is nearly complete except for the modification of a moyno-type pump; the pump was shipped to the manufacturer to install a special leak-free, high pressure seal.

  8. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1992-05-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period focused on assembling the supercritical particle generation/collection system. Effort was applied to constructing a shakedown testing plan also.

  9. CARDIOVASCULAR RESPONSES IN UNRESTRAINED WKY-RATS TO INHALED ULTRAFINE CARBON PARTICLES

    EPA Science Inventory

    Abstract
    This study provides evidence for adverse cardiac effects of inhaled ultrafine particles (UFPs) in healthy WKY rats. Short term exposure (24 h) with carbon UFPs (180 ?g?m ?) induced a moderate but significant heart rate increase of 18 bpm (4.8 %) in association with a ...

  10. The Effects of Vegetation Barriers on Near-road Ultrafine Particle Number and Carbon Monoxide Concentrations

    EPA Science Inventory

    Numerous studies have shown that people living in near-roadway communities (within 100 m of the road) are exposed to high ultrafine particle (UFP) number concentrations, which may be associated with adverse health effects. Vegetation barriers have been shown to affect pollutant t...

  11. PULMONARY AND CARDIAC GENE EXPRESSION FOLLOWING ACUTE ULTRAFINE CARBON PARTICLE INHALATION IN HYPERTENSIVE RATS

    EPA Science Inventory

    Inhalation of ultrafine carbon particles (ufCP) causes cardiac physiological changes without marked pulmonary injury or inflammation. We hypothesized that acute ufCP exposure of 13 months old Spontaneously Hypertensive (SH) rats will cause differential effects on the lung and hea...

  12. Combustion of PTFE: The effects of gravity on ultrafine particle generation

    NASA Technical Reports Server (NTRS)

    McKinnon, Thomas; Todd, Paul; Oberdorster, Gunter

    1996-01-01

    The objective of this project is to obtain an understanding of the effect of gravity on the toxicity of ultrafine particle and gas phase materials produced when fluorocarbon polymers are thermally degraded or burned. The motivation for the project is to provide a basic technical foundation on which policies for spacecraft health and safety with regard to fire and polymers can be formulated.

  13. SIGNALING MECHANISMS IN HUMAN AIRWAY EPITHELIAL CELLS EXPOSED TO CARBON ULTRAFINE PARTICLES

    EPA Science Inventory

    SIGNALING MECHANISMS IN HUMAN AIRWAY EPITHELIAL CELLS EXPOSED TO CARBON ULTRAFINE PARTICLES
    Y.M. Kim, A.G. Lenz, R. Silbajoris, I. Jaspers and J.M. Samet. Department of Environmental Sciences and Engineering and Center for Environmental Medicine, University of North Carolina, ...

  14. Effect of flow characteristics on ultrafine particle emissions from range hoods.

    PubMed

    Tseng, Li-Ching; Chen, Chih-Chieh

    2013-08-01

    In order to understand the physical mechanisms of the production of nanometer-sized particulate generated from cooking oils, the ventilation of kitchen hoods was studied by determining the particle concentration, particle size distribution, particle dimensions, and hood's flow characteristics under several cooking scenarios. This research varied the temperature of the frying operation on one cooking operation, with three kinds of commercial cooking oils including soybean oil, olive oil, and sunflower oil. The variations of particle concentration and size distributions with the elevated cooking oil temperatures were presented. The particle concentration increases as a function of temperature. For oil temperatures ranging between 180°C and 210°C, a 5°C increase in temperature increased the number concentration of ultrafine particles by 20-50%. The maximum concentration of ultrafine particles was found to be approximately 6 × 10(6) particles per cm(3) at 260°C. Flow visualization techniques and particle distribution measurement were performed for two types of hood designs, a wall-mounted range hood and an island hood, at a suction flow rate of 15 m(3) min(-1). The flow visualization results showed that different configurations of kitchen hoods induce different aerodynamic characteristics. By comparing the results of flow visualizations and nanoparticle measurements, it was found that the areas with large-scale turbulent vortices are more prone to dispersion of ultrafine particle leakage because of the complex interaction between the shear layers and the suction movement that results from turbulent dispersion. We conclude that the evolution of ultrafine particle concentration fluctuations is strongly affected by the location of the hood, which can alter the aerodynamic features. We suggest that there is a correlation between flow characteristics and amount of contaminant leakage. This provides a comprehensive strategy to evaluate the effectiveness of kitchen hoods

  15. Ultrafine particles emitted by flame and electric arc guns for thermal spraying of metals.

    PubMed

    Bémer, Denis; Régnier, Roland; Subra, Isabelle; Sutter, Benjamin; Lecler, Marie T; Morele, Yves

    2010-08-01

    The ultrafine aerosol emitted by thermal spraying of metals using flame and electric arc processes has been characterized in terms of particle size distribution and emission rates based on both particle number and mass. Thermal spraying of Zn, Zn/Al, and Al was studied. Measurements taken using an electrical low pressure impactor and a condensation nucleus counter reveal an aerosol made up of very fine particles (80-95% of number distribution <100 nm). Ultrafine particle emission rates produced by the electric arc process are very high, the largest values being recorded during spraying of pure aluminium. This process generates high particle emissions and therefore requires careful consideration and possible rethinking of currently implemented protection measures: ventilated cabins, dust collectors, and personal protective equipment.

  16. Fabrication of a pure, uniform electroless silver film using ultrafine silver aerosol particles.

    PubMed

    Byeon, Jeong Hoon; Kim, Jang-Woo

    2010-07-20

    To obtain evenly distributed pure Ag particles with a narrow size distribution on a polymer membrane, a novel activation procedure with an environmentally friendly, cost-effective method was utilized as a pretreatment before electroless Ag deposition. The pretreatment was first performed on an untreated membrane surface by collecting ultrafine ambient spark-generated Ag aerosol particles. After annealing, the electroless Ag film was fabricated on the collected aerosol particles in the Ag electroless bath. Experimental characterizations showed that the ultrafine Ag particles were uniformly anchored onto the membrane surface through pretreatment, resulting in a pure Ag film of closely packed particles with a narrow size distribution on the membrane, and the properties were comparable to those of an Ag film on wet Sn-Ag-activated membranes.

  17. Method for the production of ultrafine particles by electrohydrodynamic micromixing

    DOEpatents

    DePaoli, David W.; Hu, Zhong Cheng; Tsouris, Constantinos

    2001-01-01

    The present invention relates to a method for the rapid production of homogeneous, ultrafine inorganic material via liquid-phase reactions. The method of the present invention employs electrohydrodynamic flows in the vicinity of an electrified injector tube placed inside another tube to induce efficient turbulent mixing of two fluids containing reactive species. The rapid micromixing allows liquid-phase reactions to be conducted uniformly at high rates. This approach allows continuous production of non-agglomerated, monopispersed, submicron-sized, sphere-like powders.

  18. Pulmonary and systemic distribution of inhaled ultrafine silver particles in rats.

    PubMed

    Takenaka, S; Karg, E; Roth, C; Schulz, H; Ziesenis, A; Heinzmann, U; Schramel, P; Heyder, J

    2001-08-01

    The cardiovascular system is currently considered a target for particulate matter, especially for ultrafine particles. In addition to autonomic or cytokine mediated effects, the direct interaction of inhaled materials with the target tissue must be examined to understand the underlying mechanisms. In the first approach, pulmonary and systemic distribution of inhaled ultrafine elemental silver (EAg) particles was investigated on the basis of morphology and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Rats were exposed for 6 hr at a concentration of 133 microg EAg m(3) (3 x 10(6) cm(3), 15 nm modal diameter) and were sacrificed on days 0, 1, 4, and 7. ICP-MS analysis showed that 1.7 microg Ag was found in the lungs immediately after the end of exposure. Amounts of Ag in the lungs decreased rapidly with time, and by day 7 only 4% of the initial burden remained. In the blood, significant amounts of Ag were detected on day 0 and thereafter decreased rapidly. In the liver, kidney, spleen, brain, and heart, low concentrations of Ag were observed. Nasal cavities, especially the posterior portion, and lung-associated lymph nodes showed relatively high concentrations of Ag. For comparison, rats received by intratracheal instillation either 150 microL aqueous solution of 7 microg silver nitrate (AgNO(3) (4.4 microg Ag) or 150 microL aqueous suspension of 50 microg agglomerated ultrafine EAg particles. A portion of the agglomerates remained undissolved in the alveolar macrophages and in the septum for at least 7 days. In contrast, rapid clearance of instilled water-soluble AgNO(3) from the lung was observed. These findings show that although instilled agglomerates of ultrafine EAg particles were retained in the lung, Ag was rapidly cleared from the lung after inhalation of ultrafine EAg particles, as well as after instillation of AgNO(3), and entered systemic pathways.

  19. A system for aerodynamically sizing ultrafine environmental radioactive particles

    SciTech Connect

    Olawoyin, L.

    1995-09-01

    The unattached environmental radioactive particles/clusters, produced mainly by {sup 222}Rn in indoor air, are usually few nanometers in size. The inhalation of these radioactive clusters can lead to deposition of radioactivity on the mucosal surface of the tracheobronchial tree. The ultimate size of the cluster together with the flow characteristics will determine the depositional site in the human lung and thus, the extent of damage that can be caused. Thus, there exists the need for the determination of the size of the radioactive clusters. However, the existing particle measuring device have low resolution in the sub-nanometer range. In this research, a system for the alternative detection and measurement of the size of particles/cluster in the less than 2 nm range have been developed. The system is a one stage impactor which has a solid state spectrometer as its impaction plate. It`s major feature is the nozzle-to-plate separation, L. The particle size collected changes with L and thus, particle size spectroscopy is achieved by varying L. The number of collected particles is determined by alpha spectroscopy. The size-discriminating ability of the system was tested with laboratory generated radon particles and it was subsequently used to characterize the physical (size) changes associated with the interaction of radon progeny with water vapor and short chain alcohols in various support gases. The theory of both traditional and high velocity jet impactors together with the design and evaluation of the system developed in this study are discussed in various chapters of this dissertation. The major results obtained in the course of the study are also presented.

  20. Environmental and health impacts of fine and ultrafine metallic particles: assessment of threat scores.

    PubMed

    Goix, Sylvaine; Lévêque, Thibaut; Xiong, Tian-Tian; Schreck, Eva; Baeza-Squiban, Armelle; Geret, Florence; Uzu, Gaëlle; Austruy, Annabelle; Dumat, Camille

    2014-08-01

    This study proposes global threat scores to prioritize the harmfulness of anthropogenic fine and ultrafine metallic particles (FMP) emitted into the atmosphere at the global scale. (Eco)toxicity of physicochemically characterized FMP oxides for metals currently observed in the atmosphere (CdO, CuO, PbO, PbSO(4), Sb(2)O(3), and ZnO) was assessed by performing complementary in vitro tests: ecotoxicity, human bioaccessibility, cytotoxicity, and oxidative potential. Using an innovative methodology based on the combination of (eco)toxicity and physicochemical results, the following hazard classification of the particles is proposed: CdCl2~CdO>CuO>PbO>ZnO>PbSO(4)>Sb(2)O(3). Both cadmium compounds exhibited the highest threat score due to their high cytotoxicity and bioaccessible dose, whatever their solubility and speciation, suggesting that cadmium toxicity is due to its chemical form rather than its physical form. In contrast, the Sb(2)O(3) threat score was the lowest due to particles with low specific area and solubility, with no effects except a slight oxidative stress. As FMP physicochemical properties reveal differences in specific area, crystallization systems, dissolution process, and speciation, various mechanisms may influence their biological impact. Finally, this newly developed and global approach could be widely used in various contexts of pollution by complex metal particles and may improve risk management.

  1. Ultrafine particle emission of waste incinerators and comparison to the exposure of urban citizens.

    PubMed

    Buonanno, Giorgio; Morawska, Lidia

    2015-03-01

    On the basis of the growing interest on the impact of airborne particles on human exposure as well as the strong debate in Western countries on the emissions of waste incinerators, this work reviewed existing literature to: (i) show the emission factors of ultrafine particles (particles with a diameter less than 100 nm) of waste incinerators; and (ii) assess the contribution of waste incinerators in terms of ultrafine particles to exposure and dose of people living in the surrounding areas of the plants in order to estimate eventual risks. The review identified only a limited number of studies measuring ultrafine particle emissions, and in general they report low particle number concentrations at the stack (the median value was equal to 5.5×10(3) part cm(-3)), in most cases higher than the outdoor background value. The lowest emissions were achieved by utilization of the bag-house filter which has an overall number-based filtration efficiency higher than 99%. Referring to reference case, the corresponding emission factor is equal to 9.1×10(12) part min(-1), that is lower than one single high-duty vehicle. Since the higher particle number concentrations found in the most contributing microenvironments to the exposure (indoor home, transportation, urban outdoor), the contribution of the waste incinerators to the daily dose can be considered as negligible.

  2. Assessment of exposure to airborne ultrafine particles in the urban environment of Lisbon, Portugal.

    PubMed

    Albuquerque, P C; Gomes, J F; Bordado, J C

    2012-04-01

    The aim of this study was the assessment of exposure to ultrafine in the urban environment ofLisbon, Portugal, due to automobile traffic, and consisted of the determination of deposited alveolar surface area in an avenue leading to the town center during late spring. This study revealed differentiated patterns for weekdays and weekends, which could be related with the fluxes of automobile traffic. During a typical week, ultrafine particles alveolar deposited surface area varied between 35.0 and 89.2 microm2/cm3, which is comparable with levels reported for other towns such in Germany and the United States. These measurements were also complemented by measuring the electrical mobility diameter (varying from 18.3 to 128.3 nm) and number of particles that showed higher values than those previously reported for Madrid and Brisbane. Also, electron microscopy showed that the collected particles were composed of carbonaceous agglomerates, typical of particles emitted by the exhaustion of diesel vehicles.

  3. Monte Carlo N-Particle Tracking of Ultrafine Particle Flow in Bent Micro-Tubes

    SciTech Connect

    Casella, Andrew M.; Loyalka, Sudarsham K.

    2016-02-16

    The problem of large pressure-differential driven laminar convective-diffusive ultrafine aerosol flow through bent micro-tubes is of interest in several contemporary research areas including; release of contents from pressurized containment vessels, aerosol sampling equipment, advanced scientific instruments, gas-phase micro-heat exchangers, and microfluidic devices. In each of these areas, the predominant problem is the determination of the fraction of particles entering the micro-tube that is deposited within the tube and the fraction that is transmitted through. Due to the extensive parameter restrictions of this class of problems, a Lagrangian particle tracking method making use of the coupling of the analytical stream line solutions of Dean and the simplified Langevin equation is quite a useful tool in problem characterization. This method is a direct analog to the Monte Carlo N-Particle method of particle transport extensively used in nuclear physics and engineering. In this work, 10 nm diameter particles with a density of 1 g/cm3 are tracked within micro-tubes with toroidal bends with pressure differentials ranging between 0.2175 and 0.87 atmospheres. The tubes have radii of 25 microns and 50 microns and the radius of curvature is between 1 m and 0.3183 cm. The carrier gas is helium, and temperatures of 298 K and 558 K are considered. Numerical convergence is considered as a function of time step size and of the number of particles per simulation. Particle transmission rates and deposition patterns within the bent micro-tubes are calculated.

  4. INDOOR AND OUTDOOR ULTRA-FINE PARTICLE COUNTS IN A 1999 TWO-SEASON FRESNO, CALIFORNIA, USA ACUTE CARDIAC PANEL STUDY

    EPA Science Inventory

    Indoor and Outdoor Ultrafine Particle Counts in a 1999 Two-Season Fresno, California, USA Acute Cardiac Panel Study.

    John Creason, Debra Walsh, Lucas Neas, US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects R...

  5. Number size distribution of fine and ultrafine fume particles from various welding processes.

    PubMed

    Brand, Peter; Lenz, Klaus; Reisgen, Uwe; Kraus, Thomas

    2013-04-01

    Studies in the field of environmental epidemiology indicate that for the adverse effect of inhaled particles not only particle mass is crucial but also particle size is. Ultrafine particles with diameters below 100 nm are of special interest since these particles have high surface area to mass ratio and have properties which differ from those of larger particles. In this paper, particle size distributions of various welding and joining techniques were measured close to the welding process using a fast mobility particle sizer (FMPS). It turned out that welding processes with high mass emission rates (manual metal arc welding, metal active gas welding, metal inert gas welding, metal inert gas soldering, and laser welding) show mainly agglomerated particles with diameters above 100 nm and only few particles in the size range below 50 nm (10 to 15%). Welding processes with low mass emission rates (tungsten inert gas welding and resistance spot welding) emit predominantly ultrafine particles with diameters well below 100 nm. This finding can be explained by considerably faster agglomeration processes in welding processes with high mass emission rates. Although mass emission is low for tungsten inert gas welding and resistance spot welding, due to the low particle size of the fume, these processes cannot be labeled as toxicologically irrelevant and should be further investigated.

  6. Determinants of personal exposure to PM2.5, ultrafine particle counts, and CO in a transport microenvironment.

    PubMed

    Kaur, S; Nieuwenhuijsen, M J

    2009-07-01

    Short-term human exposure concentrations to PM2.5, ultrafine particle counts (particle range: 0.02-1 microm), and carbon monoxide (CO) were investigated at and around a street canyon intersection in Central London, UK. During a four week field campaign, groups of four volunteers collected samples at three timings (morning, lunch, and afternoon), along two different routes (a heavily trafficked route and a backstreet route) via five modes of transport (walking, cycling, bus, car, and taxi). This was followed by an investigation into the determinants of exposure using a regression technique which incorporated the site-specific traffic counts, meteorological variables (wind speed and temperature) and the mode of transport used. The analyses explained 9, 62, and 43% of the variability observed in the exposure concentrations to PM2.5, ultrafine particle counts, and CO in this study, respectively. The mode of transport was a statistically significant determinant of personal exposure to PM2.5, ultrafine particle counts, and CO, and for PM2.5 and ultrafine particle counts it was the most important determinant. Traffic count explained little of the variability in the PM2.5 concentrations, but it had a greater influence on ultrafine particle count and CO concentrations. The analyses showed that temperature had a statistically significant impact on ultrafine particle count and CO concentrations. Wind speed also had a statistically significant effect but smaller. The small proportion in variability explained in PM2.5 by the model compared to the largest proportion in ultrafine particle counts and CO may be due to the effect of long-range transboundary sources, whereas for ultrafine particle counts and CO, local traffic is the main source.

  7. Mineralogical characterization of ambient fine/ultrafine particles emitted from Xuanwei C1 coal combustion

    NASA Astrophysics Data System (ADS)

    Lu, Senlin; Hao, Xiaojie; Liu, Dingyu; Wang, Qiangxiang; Zhang, Wenchao; Liu, Pinwei; Zhang, Rongci; Yu, Shang; Pan, Ruiqi; Wu, Minghong; Yonemochi, Shinich; Wang, Qingyue

    2016-03-01

    Nano-quartz in Xuanwei coal, the uppermost Permian (C1) coal deposited in the northwest of Yuanan, China, has been regarded as one of factors which caused high lung cancer incidence in the local residents. However, mineralogical characterization of the fine/ultrafine particles emitted from Xuanwei coal combustion has not previously been studied. In this study, PM1 and ultrafine particles emitted from Xuanwei coal combustion were sampled. Chemical elements in the ambient particles were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and mineralogical characterization of these ambient particles was investigated using scanning electronic microscopy (SEM/EDX) and transmission electronic microscopy, coupled with energy-dispersive spectroscopy (TEM/EDX). Our results showed that the size distribution of mineral particles from the coal combustion emissions ranged from 20 to 200 nm. Si-containing particles and Fe-containing particles accounted for 50.7% of the 150 individual particles measured, suggesting that these two types of particles were major minerals in the ambient particles generally. The nano-mineral particles were identified as quartz (SiO2) and gypsum (CaSO4) based on their crystal parameters and chemical elements. Additionally, there also existed unidentified nano-minerals. Armed with these data, toxicity assessments of the nano-minerals will be carried out in a future study.

  8. Aerosol-CFD modelling of ultrafine and black carbon particle emission, dilution, and growth near roadways

    NASA Astrophysics Data System (ADS)

    Huang, L.; Gong, S. L.; Gordon, M.; Liggio, J.; Staebler, R. M.; Stroud, C. A.; Lu, G.; Mihele, C.; Brook, J. R.; Jia, C. Q.

    2014-05-01

    Many studies have shown that on-road vehicle emissions are the dominant source of ultrafine particles (UFP; diameter < 100 nm) in urban areas and near-roadway environments. In order to advance our knowledge on the complex interactions and competition among atmospheric dilution, dispersion and dynamics of UFPs, an aerosol dynamics-CFD coupled model is developed and validated against field measurements. A unique approach of applying periodic boundary conditions is proposed to model pollutant dispersion and dynamics in one unified domain from the tailpipe level to the ambient near-road environment. This approach significantly reduces the size of the computational domain, and therefore, allows fast simulation of multiple scenarios. The model is validated against measured turbulent kinetic energy (TKE) and pollution gradients near a major highway. Through a model sensitivity analysis, the relative importance of individual aerosol dynamical processes on the total particle number concentration (N) and particle number-size distribution (PSD) near a highway is investigated. The results demonstrate that (1) coagulation has a negligible effect on N and particle growth, (2) binary homogeneous nucleation (BHN) of H2SO4-H2O is likely responsible for elevated N closest to the road, (3) N and particle growth are very sensitive to the condensation of semi-volatile organics (SVOCs), particle dry deposition, and the interaction between these processes. The results also indicate that, without the proper treatment of atmospheric boundary layer (i.e. its wind profile and turbulence quantities), the nucleation rate would be underestimated by a factor of 5 in the vehicle wake region due to overestimated mixing. Therefore, introducing ABL conditions to activity-based emission models may potentially improve their performance in estimating UFP traffic emissions.

  9. Long-term assessment of ultrafine particles on major roadways in Las Vegas, Nevada and Detroit, Michigan

    EPA Science Inventory

    This is a presentation at the National Air Monitoring conference, given at the request of OAQPS partners. The presentation will cover ultrafine particle data collected at three locations - Las Vegas, Detroit, and Research Triangle Park.

  10. Effect of ultrafine gold particles and cationic surfactant on burning as-grown single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Yudasaka, M.; Nihey, F.; Iijima, S.

    2000-10-01

    Mizoguti et al. (Chem. Phys. Lett. 321 (2000) 297) reported that amorphous carbon (a-C) contained in as-grown single-wall carbon nanotubes could be burned preferentially by using ultrafine gold particles and cationic surfactant, benzalkonium chloride (BKC). We confirmed this result and found additionally that the optimum concentration of the ultrafine gold particles and BKC were, respectively, 0.6 atom% and 7 g/l. We studied the roles of ultrafine gold particles and BKC in this phenomenon; the ultrafine gold particles catalyzed the oxidation of carbonaceous materials leading to the decrease of the burning temperatures. BKC had the function of homogenizing the a-C aggregation states, which resulted in the burning of a-C in a narrow temperature range.

  11. ULTRAFINE CARBON PARTICLES INDUCE INTERLEUKIN-8 GENE TRANSCRIPTION AND P38 MAPK ACTIVATION IN NORMAL BRONCHIAL EPITHELIAL CELLS

    EPA Science Inventory

    Epidemiological studies suggest that ultrafine particles contribute to particulate matter-induced adverse health effects. Interleukin (IL)-8 is an important proinflammatory cytokine in the human lung that is induced in respiratory cells exposed to a variety of environmental insul...

  12. Exposure for ultrafine carbon particles at levels below detectable pulmonary inflammation affects cardiovascular performance in spontaneously hypertensive rats*

    EPA Science Inventory

    Rationale: Exposure to particulate matter is a risk factor for cardiopulmonary disease but the related molecular mechanisms are poorly understood. Previously we studied cardiovascular responses in healthy WKY rats following inhalation exposure to ultrafine carbon particles (UfCPs...

  13. Distribution pattern of inhaled ultrafine gold particles in the rat lung.

    PubMed

    Takenaka, S; Karg, E; Kreyling, W G; Lentner, B; Möller, W; Behnke-Semmler, M; Jennen, L; Walch, A; Michalke, B; Schramel, P; Heyder, J; Schulz, H

    2006-09-01

    The role of alveolar macrophages in the fate of ultrafine particles in the lung was investigated. Male Wistar-Kyoto rats were exposed to ultrafine gold particles, generated by a spark generator, for 6 h at a concentration of 88 microg/m3 (4 x 10(6)/cm3, 16 nm modal mobility diameter). Up to 7 days, the animals were serially sacrificed, and lavaged cells and lung tissues were examined by transmission electron microscopy. The gold concentration/content in the lung, lavage fluid, and blood was estimated by inductively coupled plasma-mass spectrometry. Gold particles used were spherical and electron dense with diameters of 5-8 nm. The particles were individual or slightly agglomerated. By inductively coupled plasma-mass spectrometry analysis of the lung, 1945 +/- 57 ng (mean +/- SD) and 1512 +/- 184 ng of gold were detected on day 0 and on day 7, respectively, indicating that a large portion of the deposited gold particles was retained in the lung tissue. In the lavage fluid, 573 +/- 67 ng and 96 +/- 29 ng were found on day 0 and day 7, respectively, which means that 29% and 6% of the retained gold particles were lavageable on these days. A low but significant increase of gold (0.03 to 0.06% of lung concentration) was found in the blood. Small vesicles containing gold particles were found in the cytoplasm of alveolar macrophages. In the alveolar septum, the gold particles were enclosed in vesicles observed in the cytoplasm of alveolar type I epithelial cells. These results indicate that inhaled ultrafine gold particles in alveolar macrophages and type I epithelial cells are processed by endocytotic pathways, though the uptake of the gold particles by alveolar macrophages is limited. To a low degree, systemic particle translocation took place.

  14. Increased ultrafine particles and carbon monoxide concentrations are associated with asthma exacerbation among urban children

    PubMed Central

    Evans, Kristin A.; Halterman, Jill S.; Hopke, Philip K.; Fagnano, Maria; Rich, David Q.

    2014-01-01

    Objectives Increased air pollutant concentrations have been linked to several asthma-related outcomes in children, including respiratory symptoms, medication use, and hospital visits. However, few studies have examined effects of ultrafine particles in a pediatric population. Our primary objective was to examine the effects of ambient concentrations of ultrafine particles on asthma exacerbation among urban children and determine whether consistent treatment with inhaled corticosteroids could attenuate these effects. We also explored the relationship between asthma exacerbation and ambient concentrations of accumulation mode particles, fine particles (≤ 2.5 micrograms [μm]; PM2.5), carbon monoxide, sulfur dioxide, and ozone. We hypothesized that increased 1 to 7 day concentrations of ultrafine particles and other pollutants would be associated with increases in the relative odds of an asthma exacerbation, but that this increase in risk would be attenuated among children receiving school-based corticosteroid therapy. Methods We conducted a pilot study using data from 3–10 year-old children participating in the School-Based Asthma Therapy trial. Using a time-stratified case-crossover design and conditional logistic regression, we estimated the relative odds of a pediatric asthma visit treated with prednisone (n=96 visits among 74 children) associated with increased pollutant concentrations in the previous 7 days. We re-ran these analyses separately for children receiving medications through the school-based intervention and children in a usual care control group. Results Interquartile range increases in ultrafine particles and carbon monoxide concentrations in the previous 7 days were associated with increases in the relative odds of a pediatric asthma visit, with the largest increases observed for 4-day mean ultrafine particles (interquartile range=2088 p/cm3; OR=1.27; 95% CI=0.90–1.79) and 7-day mean carbon monoxide (interquartile range=0.17 ppm; OR=1.63; 95

  15. Exposure assessment of a cyclist to PM10 and ultrafine particles.

    PubMed

    Berghmans, P; Bleux, N; Int Panis, L; Mishra, V K; Torfs, R; Van Poppel, M

    2009-02-01

    Estimating personal exposure to air pollution is a crucial component in identifying high-risk populations and situations. It will enable policy makers to determine efficient control strategies. Cycling is again becoming a favorite mode of transport both in developing and in developed countries due to increasing traffic congestion and environmental concerns. In Europe, it is also seen as a healthy sports activity. However, due to high levels of hazardous pollutants in the present day road microenvironment the cyclist might be at a higher health risk due to higher breathing rate and proximity to the vehicular exhaust. In this paper we present estimates of the exposure of a cyclist to particles of various size fractions including ultrafine particles (UFP) in the town of Mol (Flanders, Belgium). The results indicate relatively higher UFP concentration exposure during morning office hours and moderate UFP levels during afternoon. The major sources of UFP and PM(10) were identified, which are vehicular emission and construction activities, respectively. We also present a dust mapping technique which can be a useful tool for town planners and local policy makers.

  16. Environmental and health impacts of fine and ultrafine metallic particles: Assessment of threat scores

    SciTech Connect

    Goix, Sylvaine; Lévêque, Thibaut; Xiong, Tian-Tian; Schreck, Eva; and others

    2014-08-15

    This study proposes global threat scores to prioritize the harmfulness of anthropogenic fine and ultrafine metallic particles (FMP) emitted into the atmosphere at the global scale. (Eco)toxicity of physicochemically characterized FMP oxides for metals currently observed in the atmosphere (CdO, CuO, PbO, PbSO{sub 4}, Sb{sub 2}O{sub 3}, and ZnO) was assessed by performing complementary in vitro tests: ecotoxicity, human bioaccessibility, cytotoxicity, and oxidative potential. Using an innovative methodology based on the combination of (eco)toxicity and physicochemical results, the following hazard classification of the particles is proposed: CdCl{sub 2}∼CdO>CuO>PbO>ZnO>PbSO{sub 4}>Sb{sub 2}O{sub 3}. Both cadmium compounds exhibited the highest threat score due to their high cytotoxicity and bioaccessible dose, whatever their solubility and speciation, suggesting that cadmium toxicity is due to its chemical form rather than its physical form. In contrast, the Sb{sub 2}O{sub 3} threat score was the lowest due to particles with low specific area and solubility, with no effects except a slight oxidative stress. As FMP physicochemical properties reveal differences in specific area, crystallization systems, dissolution process, and speciation, various mechanisms may influence their biological impact. Finally, this newly developed and global approach could be widely used in various contexts of pollution by complex metal particles and may improve risk management. - Highlights: • Seven micro- and nano- monometallic characterized particles were studied as references. • Bioaccessibility, eco and cytotoxicity, and oxidative potential assays were performed. • According to calculated threat scores: CdCl{sub 2}∼CdO>CuO>PbO>ZnO>PbSO{sub 4}>Sb{sub 2}O{sub 3}.

  17. 3D Air Filtration Modeling for Nanofiber Based Filters in the Ultrafine Particle Size Range

    NASA Astrophysics Data System (ADS)

    Sambaer, Wannes; Zatloukal, Martin; Kimmer, Dusan

    2011-07-01

    In this work, novel 3D filtration model for nanofiber based filters has been proposed and tested. For the model validation purposes, filtration efficiency characteristics of two different polyurethane nanofiber based structures (prepared by the electrospinning process) were determined experimentally in the ultrafine particle size range (20-400 nm). It has been found that the proposed model is able to reasonably predict the measured filtration efficiency curves for both tested samples.

  18. An innovative antisolvent precipitation process as a promising technique to prepare ultrafine rifampicin particles

    NASA Astrophysics Data System (ADS)

    Viçosa, Alessandra; Letourneau, Jean-Jacques; Espitalier, Fabienne; Inês Ré, Maria

    2012-03-01

    Many existing and new drugs fail to be fully utilized because of their limited bioavailability due to poor solubility in aqueous media (BCS drug classes II and IV). In this work, for accelerating dissolution of this kind of poorly water-soluble drugs, an antisolvent precipitation method that does not require the use of conventional volatile organic solvents is proposed. To demonstrate this technique, ultrafine particles of rifampicin were prepared using a room temperature ionic liquid (1-ethyl 3- methyl imidazolium methyl-phosphonate) as an alternative solvent and a phosphate buffer as an antisolvent. Rifampicin solubility was measured in various solvents (1-ethyl 3-methyl imidazolium methylphosphonate, water and phosphate buffer), showing the RTIL good solvency for the model drug: rifampicin solubility was found to be higher than 90 mg/g in RTIL at 30 °C and lower than 1 mg/g in water at 25 °C. Additionally, it was demonstrated that introduction of rifampicin solution in 1-ethyl 3- methyl imidazolium methyl-phosphonate into the aqueous solution antisolvent can produce particles in the submicron range with or without hydroxypropyl methylcellulose as the stabilizer. The ultrafine particles (280-360 nm) are amorphous with enhanced solubility and faster dissolution rate. To our knowledge, this is the first published work examining the suitability of using RTILs for ultrafine drug nanoparticles preparation by an antisolvent precipitation process.

  19. Land Use Regression Models for Ultrafine Particles in Six European Areas

    PubMed Central

    2017-01-01

    Long-term ultrafine particle (UFP) exposure estimates at a fine spatial scale are needed for epidemiological studies. Land use regression (LUR) models were developed and evaluated for six European areas based on repeated 30 min monitoring following standardized protocols. In each area; Basel (Switzerland), Heraklion (Greece), Amsterdam, Maastricht, and Utrecht (“The Netherlands”), Norwich (United Kingdom), Sabadell (Spain), and Turin (Italy), 160–240 sites were monitored to develop LUR models by supervised stepwise selection of GIS predictors. For each area and all areas combined, 10 models were developed in stratified random selections of 90% of sites. UFP prediction robustness was evaluated with the intraclass correlation coefficient (ICC) at 31–50 external sites per area. Models from Basel and The Netherlands were validated against repeated 24 h outdoor measurements. Structure and model R2 of local models were similar within, but varied between areas (e.g., 38–43% Turin; 25–31% Sabadell). Robustness of predictions within areas was high (ICC 0.73–0.98). External validation R2 was 53% in Basel and 50% in The Netherlands. Combined area models were robust (ICC 0.93–1.00) and explained UFP variation almost equally well as local models. In conclusion, robust UFP LUR models could be developed on short-term monitoring, explaining around 50% of spatial variance in longer-term measurements. PMID:28244744

  20. Land Use Regression Models for Ultrafine Particles in Six European Areas.

    PubMed

    van Nunen, Erik; Vermeulen, Roel; Tsai, Ming-Yi; Probst-Hensch, Nicole; Ineichen, Alex; Davey, Mark; Imboden, Medea; Ducret-Stich, Regina; Naccarati, Alessio; Raffaele, Daniela; Ranzi, Andrea; Ivaldi, Cristiana; Galassi, Claudia; Nieuwenhuijsen, Mark; Curto, Ariadna; Donaire-Gonzalez, David; Cirach, Marta; Chatzi, Leda; Kampouri, Mariza; Vlaanderen, Jelle; Meliefste, Kees; Buijtenhuijs, Daan; Brunekreef, Bert; Morley, David; Vineis, Paolo; Gulliver, John; Hoek, Gerard

    2017-03-21

    Long-term ultrafine particle (UFP) exposure estimates at a fine spatial scale are needed for epidemiological studies. Land use regression (LUR) models were developed and evaluated for six European areas based on repeated 30 min monitoring following standardized protocols. In each area; Basel (Switzerland), Heraklion (Greece), Amsterdam, Maastricht, and Utrecht ("The Netherlands"), Norwich (United Kingdom), Sabadell (Spain), and Turin (Italy), 160-240 sites were monitored to develop LUR models by supervised stepwise selection of GIS predictors. For each area and all areas combined, 10 models were developed in stratified random selections of 90% of sites. UFP prediction robustness was evaluated with the intraclass correlation coefficient (ICC) at 31-50 external sites per area. Models from Basel and The Netherlands were validated against repeated 24 h outdoor measurements. Structure and model R(2) of local models were similar within, but varied between areas (e.g., 38-43% Turin; 25-31% Sabadell). Robustness of predictions within areas was high (ICC 0.73-0.98). External validation R(2) was 53% in Basel and 50% in The Netherlands. Combined area models were robust (ICC 0.93-1.00) and explained UFP variation almost equally well as local models. In conclusion, robust UFP LUR models could be developed on short-term monitoring, explaining around 50% of spatial variance in longer-term measurements.

  1. Ultrafine carbon particles down-regulate CYP1B1 expression in human monocytes

    PubMed Central

    Eder, Christiane; Frankenberger, Marion; Stanzel, Franz; Seidel, Albrecht; Schramm, Karl-Werner; Ziegler-Heitbrock, Loems; Hofer, Thomas PJ

    2009-01-01

    Background Cytochrome P450 monoxygenases play an important role in the defence against inhaled toxic compounds and in metabolizing a wide range of xenobiotics and environmental contaminants. In ambient aerosol the ultrafine particle fraction which penetrates deeply into the lungs is considered to be a major factor for adverse health effects. The cells mainly affected by inhaled particles are lung epithelial cells and cells of the monocyte/macrophage lineage. Results In this study we have analyzed the effect of a mixture of fine TiO2 and ultrafine carbon black Printex 90 particles (P90) on the expression of cytochrome P450 1B1 (CYP1B1) in human monocytes, macrophages, bronchial epithelial cells and epithelial cell lines. CYP1B1 expression is strongly down-regulated by P90 in monocytes with a maximum after P90 treatment for 3 h while fine and ultrafine TiO2 had no effect. CYP1B1 was down-regulated up to 130-fold and in addition CYP1A1 mRNA was decreased 13-fold. In vitro generated monocyte-derived macrophages (MDM), epithelial cell lines, and primary bronchial epithelial cells also showed reduced CYP1B1 mRNA levels. Benzo[a]pyrene (BaP) is inducing CYB1B1 but ultrafine P90 can still down-regulate gene expression at 0.1 μM of BaP. The P90-induced reduction of CYP1B1 was also demonstrated at the protein level using Western blot analysis. Conclusion These data suggest that the P90-induced reduction of CYP gene expression may interfere with the activation and/or detoxification capabilities of inhaled toxic compounds. PMID:19835593

  2. Exposure Assessment for Atmospheric Ultrafine Particles (UFPs) and Implications in Epidemiologic Research

    PubMed Central

    Sioutas, Constantinos; Delfino, Ralph J.; Singh, Manisha

    2005-01-01

    Epidemiologic research has shown increases in adverse cardiovascular and respiratory outcomes in relation to mass concentrations of particulate matter (PM) ≤2.5 or ≤10 μm in diameter (PM2.5, PM10, respectively). In a companion article [Delfino RJ, Sioutas C, Malik S. 2005. Environ Health Perspect 113(8):934–946]), we discuss epidemiologic evidence pointing to underlying components linked to fossil fuel combustion. The causal components driving the PM associations remain to be identified, but emerging evidence on particle size and chemistry has led to some clues. There is sufficient reason to believe that ultrafine particles < 0.1 μm (UFPs) are important because when compared with larger particles, they have order of magnitudes higher particle number concentration and surface area, and larger concentrations of adsorbed or condensed toxic air pollutants (oxidant gases, organic compounds, transition metals) per unit mass. This is supported by evidence of significantly higher in vitro redox activity by UFPs than by larger PM. Although epidemiologic research is needed, exposure assessment issues for UFPs are complex and need to be considered before undertaking investigations of UFP health effects. These issues include high spatial variability, indoor sources, variable infiltration of UFPs from a variety of outside sources, and meteorologic factors leading to high seasonal variability in concentration and composition, including volatility. To address these issues, investigators need to develop as well as validate the analytic technologies required to characterize the physical/chemical nature of UFPs in various environments. In the present review, we provide a detailed discussion of key characteristics of UFPs, their sources and formation mechanisms, and methodologic approaches to assessing population exposures. PMID:16079062

  3. Combustion-derived ultrafine particles transport organic toxicants to target respiratory cells.

    PubMed

    Penn, Arthur; Murphy, Gleeson; Barker, Steven; Henk, William; Penn, Lynn

    2005-08-01

    Epidemiologic evidence supports associations between inhalation of fine and ultrafine ambient particulate matter [aerodynamic diameter < or = 2.5 microm (PM2.5)] and increases in cardiovascular/respiratory morbidity and mortality. Less attention has been paid to how the physical and chemical characteristics of these particles may influence their interactions with target cells. Butadiene soot (BDS), produced during combustion of the high-volume petrochemical 1,3-butadiene, is rich in polynuclear aromatic hydrocarbons (PAHs), including known carcinogens. We conducted experiments to characterize BDS with respect to particle size distribution, assembly, PAH composition, elemental content, and interaction with respiratory epithelial cells. Freshly generated, intact BDS is primarily (> 90%) PAH-rich, metals-poor (nickel, chromium, and vanadium concentrations all < 1 ppm) PM2.5, composed of uniformly sized, solid spheres (30-50 nm) in aggregated form. Cells of a human bronchial epithelial cell line (BEAS-2B) exhibit sequential fluorescent responses--a relatively rapid (approximately 30 min), bright but diffuse fluorescence followed by the slower (2-4 hr) appearance of punctate cytoplasmic fluorescence--after BDS is added to medium overlying the cells. The fluorescence is associated with PAH localization in the cells. The ultrafine BDS particles move down through the medium to the cell membrane. Fluorescent PAHs are transferred from the particle surface to the cell membrane, cross the membrane into the cytosol, and appear to accumulate in lipid vesicles. There is no evidence that BDS particles pass into the cells. The results demonstrate that uptake of airborne ultrafine particles by target cells is not necessary for transfer of toxicants from the particles to the cells.

  4. Combustion-Derived Ultrafine Particles Transport Organic Toxicants to Target Respiratory Cells

    PubMed Central

    Penn, Arthur; Murphy, Gleeson; Barker, Steven; Henk, William; Penn, Lynn

    2005-01-01

    Epidemiologic evidence supports associations between inhalation of fine and ultrafine ambient particulate matter [aerodynamic diameter ≤ 2.5 μm (PM2.5)] and increases in cardiovascular/respiratory morbidity and mortality. Less attention has been paid to how the physical and chemical characteristics of these particles may influence their interactions with target cells. Butadiene soot (BDS), produced during combustion of the high-volume petrochemical 1,3-butadiene, is rich in polynuclear aromatic hydrocarbons (PAHs), including known carcinogens. We conducted experiments to characterize BDS with respect to particle size distribution, assembly, PAH composition, elemental content, and interaction with respiratory epithelial cells. Freshly generated, intact BDS is primarily (> 90%) PAH-rich, metals-poor (nickel, chromium, and vanadium concentrations all < 1 ppm) PM2.5, composed of uniformly sized, solid spheres (30–50 nm) in aggregated form. Cells of a human bronchial epithelial cell line (BEAS-2B) exhibit sequential fluorescent responses—a relatively rapid (~ 30 min), bright but diffuse fluorescence followed by the slower (2–4 hr) appearance of punctate cytoplasmic fluorescence—after BDS is added to medium overlying the cells. The fluorescence is associated with PAH localization in the cells. The ultrafine BDS particles move down through the medium to the cell membrane. Fluorescent PAHs are transferred from the particle surface to the cell membrane, cross the membrane into the cytosol, and appear to accumulate in lipid vesicles. There is no evidence that BDS particles pass into the cells. The results demonstrate that uptake of airborne ultrafine particles by target cells is not necessary for transfer of toxicants from the particles to the cells. PMID:16079063

  5. Characterization of ultrafine particle number concentration and new particle formation in urban environment of Taipei, Taiwan

    NASA Astrophysics Data System (ADS)

    Cheung, H. C.; Chou, C. C.-K.; Huang, W.-R.; Tsai, C.-Y.

    2013-04-01

    An intensive aerosol characterization experiment was performed at the Taipei Aerosol and Radiation Observatory (TARO, 25.02° N, 121.53° E) in the urban area of Taipei, Taiwan during July 2012. Number concentration and size distribution of aerosol particles were measured continuously, which were accompanied by concurrent measurements of mass concentration of submicron particles, PM (d ≤ 1 μm), and photolysis rate of ozone, J(O1D). The averaged number concentrations of total (Ntotal), accumulation mode (Nacu), Aitken mode (Ntotal), and nucleation mode (Nnuc) particles were 7.6 × 103 cm-3, 1.2 × 103 cm-3, 4.4 × 103 cm-3, and 1.9 × 103 cm-3, respectively. Accordingly, the ultrafine particles (UFPs, d ≤ 100 nm) accounted for 83% of the total number concentration of particles measured in this study (10 ≤ d ≤ 429 nm), indicating the importance of UFPs to the air quality and radiation budget in Taipei and its surrounding areas. An averaged Nnuc/NOx ratio of ~60 cm-3 ppbv-1 was derived from nighttime measurements, which was suggested to be the characteristic of vehicle emissions that contributed to the "urban background" of nucleation mode particles throughout a day. On the contrary, it was found that the number concentration of nucleation mode particles was independent of NOx and could be elevated up to 10 times the "urban background" levels during daytime, suggesting a substantial amount of nucleation mode particles produced from photochemical processes. Consistency in the time series of the nucleation mode particle concentration and the proxy of H2SO4 production, UVB·SO2, for new particle formation (NPF) events showed that photo-oxidation of SO2 was responsible for the formation of new particles in our study area. Moreover, analysis upon the diameter growth rate, GR, and formation rate of nucleation mode particles, J10-25, found that the values of GR (8.5 ± 6.8 nm h-1) in Taipei were comparable to other urban areas, whereas the values of J10-25 (2.2 ± 1

  6. [Experimental study on the size spectra and emission factor of ultrafine particle from coal combustion].

    PubMed

    Sun, Zai; Yang, Wen-jun; Xie, Xiao-fang; Chen, Qiu-fang; Cai, Zhi-liang

    2014-12-01

    The emission characteristics of ultrafine particles released from pulverized coal combustion were studied, the size spectra of ultrafine particles (5.6-560 nm) were measured with FMPS (fast mobility particle sizer) on a self-built aerosol experiment platform. Meanwhile, a particle dynamic evolution model was established to obtain the particle deposition rate and the emission rate through the optimized algorithm. Finally, the emission factor was calculated. The results showed that at the beginning of particle generation, the size spectra were polydisperse and complex, the initial size spectra was mainly composed of three modes including 10 nm, 30-40 nm and 100-200 nm. Among them, the number concentration of mode around 10 nm was higher than those of other modes, the size spectrum of around 100-200 nm was lognormal distributed, with a CMD (count median diameter) of around 16 nm. Then, as time went on, the total number concentration was decayed by exponential law, the CMD first increased and then tended to be stable gradually. The calculation results showed that the emission factor of particles from coal combustion under laboratory condition was (5.54 x 10(12) ± 2.18 x 10(12)) unit x g(-1).

  7. Measurements of ultrafine particles and other vehicular pollutants inside a mobile exposure system on Los Angeles freeways.

    PubMed

    Zhu, Yifang; Fung, David C; Kennedy, Nola; Hinds, William C; Eiguren-Fernandez, Arantzazu

    2008-03-01

    A mobile exposure and air pollution measurement system was developed and used for on-freeway ultrafine particle health effects studies. A nine-passenger van was modified with a high-efficiency particulate air (HEPA) filtration system that can deliver filtered or unfiltered air to an exposure chamber inside the van. State-of-the-art instruments were used to measure concentration and size distribution of fine and ultrafine particles and the concentration of carbon monoxide (CO), black carbon (BC), particle-bound polycyclic aromatic hydrocarbons (PAHs), fine particulate matter (PM2.5) mass, and oxides of nitrogen (NOx) inside the exposure chamber. This paper presents the construction and technical details of the van and air pollutant concentrations collected in 32 2-hr runs on two major Los Angeles freeways, Interstate 405 (1-405; mostly gasoline traffic) and Interstate 710 (1-710; large proportion of heavy-duty diesel traffic). More than 97% of particles were removed when the flow through the filter box was switched from bypass mode to filter mode while the vehicle was driving on both freeways. The filtration system thus provides a great particulate matter exposure contrast while keeping gas-phase pollutant concentrations the same. Under bypass mode, average total particle number concentration observed inside the exposure chamber was around 8.4 x 10(4) and 1.3 x 10(5) particles cm(-3) on the I-405 and the I-710 freeways, respectively. Bimodal size distributions were consistent and similar for both freeways with the first mode around 16-20 nm and the second mode around 50-55 nm. BC and particle-bound PAH concentrations were more than two times greater on the I-710 than on the I-405 freeway. Very weak correlations were observed between total particle number concentrations and other vehicular pollutants on the freeways.

  8. Investigation on the potential generation of ultrafine particles from the tire-road interface

    NASA Astrophysics Data System (ADS)

    Mathissen, Marcel; Scheer, Volker; Vogt, Rainer; Benter, Thorsten

    2011-11-01

    There has been some discussion in the literature on the generation of ultrafine particles from tire abrasion of studded and non-studded tires tested in the laboratory environment. In the present study, the potential generation of ultrafine particles from the tire road interface was investigated during real driving. An instrumented Sport Utility Vehicle equipped with summer tires was used to measure particle concentrations with high temporal resolution inside the wheel housing while driving on a regular asphalt road. Different driving conditions, i.e., straight driving, acceleration, braking, and cornering were applied. For normal driving conditions no enhanced particle number concentration in the size range 6-562 nm was found. Unusual maneuvers associated with significant tire slip resulted in measurable particle concentrations. The maximum of the size distribution was between 30 and 60 nm. An exponential increase of the particle concentration with velocity was measured directly at the disc brakes for full stop brakings. A tracer gas experiment was carried out to estimate the upper limit of the emission factor during normal straight driving.

  9. Axial flow cyclone for segregation and collection of ultrafine particles: theoretical and experimental study.

    PubMed

    Hsu, Yu-Du; Chein, Hung Min; Chen, Tzu Ming; Tsai, Chuen-Jinn

    2005-03-01

    In this study, an axial flow cyclone was designed, fabricated, and evaluated at different conditions of air flow rates (Q0) and low-pressure environments (P), especially for the segregation and collection of ultrafine particles. An evaporation/condensation type of aerosol generation system consisting of tube furnace and mixing chamber was employed to produce test aerosols. The test aerosol was then classified by a differential mobility analyzer (DMA) and number concentration was measured by a condensation nuclei counter (CNC) and an electrometer upstream and downstream of the cyclone, respectively. The s-shaped curve of the collection efficiency in submicron particle size range was obtained to be similar to the traditional cyclone found in the literatures when the particles were largerthan 40 nm at Q0 = 1.07, 0.455 L(STP)/min, and P = 4.8-500 Torr. The curve was found to be fitted very well by a semiempirical equation described in this paper. For particles smaller than 40 nm, however, the collection efficiency was unusually increased as the particle diameter was decreased due to the fact that the diffusion deposition becomes the dominant collection mechanism in the low-pressure conditions. A model composed of centrifugal force and diffusion deposition is presented and used to fit the experimental data. The cyclone was demonstrated to separate and collect ultrafine particles effectively in the tested vacuum conditions.

  10. Ultrafine particles: exposure and source apportionment in 56 Danish homes.

    PubMed

    Bekö, Gabriel; Weschler, Charles J; Wierzbicka, Aneta; Karottki, Dorina Gabriela; Toftum, Jørn; Loft, Steffen; Clausen, Geo

    2013-09-17

    Particle number (PN) concentrations (10-300 nm in size) were continuously measured over a period of ~45 h in 56 residences of nonsmokers in Copenhagen, Denmark. The highest concentrations were measured when occupants were present and awake (geometric mean, GM: 22.3 × 10(3) cm(-3)), the lowest when the homes were vacant (GM: 6.1 × 10(3) cm(-3)) or the occupants were asleep (GM: 5.1 × 10(3) cm(-3)). Diary entries regarding occupancy and particle related activities were used to identify source events and apportion the daily integrated exposure among sources. Source events clearly resulted in increased PN concentrations and decreased average particle diameter. For a given event, elevated particle concentrations persisted for several hours after the emission of fresh particles ceased. The residential daily integrated PN exposure in the 56 homes ranged between 37 × 10(3) and 6.0 × 10(6) particles per cm(3)·h/day (GM: 3.3 × 10(5) cm(-3)·h/day). On average, ~90% of this exposure occurred outside of the period from midnight to 6 a.m. Source events, especially candle burning, cooking, toasting, and unknown activities, were responsible on average for ~65% of the residential integrated exposure (51% without the unknown activities). Candle burning occurred in half of the homes where, on average, it was responsible for almost 60% of the integrated exposure.

  11. MEMS-based silicon cantilevers with integrated electrothermal heaters for airborne ultrafine particle sensing

    NASA Astrophysics Data System (ADS)

    Wasisto, Hutomo Suryo; Merzsch, Stephan; Waag, Andreas; Peiner, Erwin

    2013-05-01

    The development of low-cost and low-power MEMS-based cantilever sensors for possible application in hand-held airborne ultrafine particle monitors is described in this work. The proposed resonant sensors are realized by silicon bulk micromachining technology with electrothermal excitation, piezoresistive frequency readout, and electrostatic particle collection elements integrated and constructed in the same sensor fabrication process step of boron diffusion. Built-in heating resistor and full Wheatstone bridge are set close to the cantilever clamp end for effective excitation and sensing, respectively, of beam deflection. Meanwhile, the particle collection electrode is located at the cantilever free end. A 300 μm-thick, phosphorus-doped silicon bulk wafer is used instead of silicon-on-insulator (SOI) as the starting material for the sensors to reduce the fabrication costs. To etch and release the cantilevers from the substrate, inductively coupled plasma (ICP) cryogenic dry etching is utilized. By controlling the etching parameters (e.g., temperature, oxygen content, and duration), cantilever structures with thicknesses down to 10 - 20 μm are yielded. In the sensor characterization, the heating resistor is heated and generating thermal waves which induce thermal expansion and further cause mechanical bending strain in the out-of-plane direction. A resonant frequency of 114.08 +/- 0.04 kHz and a quality factor of 1302 +/- 267 are measured in air for a fabricated rectangular cantilever (500x100x13.5 μm3). Owing to its low power consumption of a few milliwatts, this electrothermal cantilever is suitable for replacing the current external piezoelectric stack actuator in the next generation of the miniaturized cantilever-based nanoparticle detector (CANTOR).

  12. A review of commuter exposure to ultrafine particles and its health effects

    NASA Astrophysics Data System (ADS)

    Knibbs, Luke D.; Cole-Hunter, Tom; Morawska, Lidia

    2011-05-01

    Ultrafine particles (UFPs, <100 nm) are produced in large quantities by vehicular combustion and are implicated in causing several adverse human health effects. Recent work has suggested that a large proportion of daily UFP exposure may occur during commuting. However, the determinants, variability and transport mode-dependence of such exposure are not well-understood. The aim of this review was to address these knowledge gaps by distilling the results of 'in-transit' UFP exposure studies performed to-date, including studies of health effects. We identified 47 exposure studies performed across 6 transport modes: automobile, bicycle, bus, ferry, rail and walking. These encompassed approximately 3000 individual trips where UFP concentrations were measured. After weighting mean UFP concentrations by the number of trips in which they were collected, we found overall mean UFP concentrations of 3.4, 4.2, 4.5, 4.7, 4.9 and 5.7 × 10 4 particles cm -3 for the bicycle, bus, automobile, rail, walking and ferry modes, respectively. The mean concentration inside automobiles travelling through tunnels was 3.0 × 10 5 particles cm -3. While the mean concentrations were indicative of general trends, we found that the determinants of exposure (meteorology, traffic parameters, route, fuel type, exhaust treatment technologies, cabin ventilation, filtration, deposition, UFP penetration) exhibited marked variability and mode-dependence, such that it is not necessarily appropriate to rank modes in order of exposure without detailed consideration of these factors. Ten in-transit health effects studies have been conducted and their results indicate that UFP exposure during commuting can elicit acute effects in both healthy and health-compromised individuals. We suggest that future work should focus on further defining the contribution of in-transit UFP exposure to total UFP exposure, exploring its specific health effects and investigating exposures in the developing world.

  13. Atmospheric Condensational Properties of Ultrafine Chain and Fractal Aerosol Particles

    NASA Technical Reports Server (NTRS)

    Marlow, William H.

    1997-01-01

    The purpose for the research sponsored by this grant was to lay the foundations for qualitative understanding and quantitative description of the equilibrium vapor pressure of water vapor over the irregularly shaped, carbonaceous particles that are present in the atmosphere. This work apparently was the first systematic treatment of the subject. Research was conducted in two complementary components: 1. Calculations were performed of the equilibrium vapor pressure of water over particles comprised of aggregates of spheres in the 50-200 nm radius range. The purposes of this work were two-fold. First, since no systematic treatment of this subject had previously been conducted, its availability would be directly useful for quantitative treatment for a limited range of atmospheric aerosols. Second, it would provide qualitative indications of the effects of highly irregular particle shape on equilibrium vapor pressure of aggregates comprised of smaller spheres.

  14. Experimental investigation of submicron and ultrafine soot particle removal by tree leaves

    NASA Astrophysics Data System (ADS)

    Hwang, Hee-Jae; Yook, Se-Jin; Ahn, Kang-Ho

    2011-12-01

    Soot particles emitted from vehicles are one of the major sources of air pollution in urban areas. In this study, five kinds of trees were selected as Pinus densiflora, Taxus cuspidata, Platanus occidentalis, Zelkova serrata, and Ginkgo biloba, and the removal of submicron (<1 μm) and ultrafine (<0.1 μm) soot particles by tree leaves was quantitatively compared in terms of deposition velocity. Soot particles were produced by a diffusion flame burner using acetylene as the fuel. The sizes of monodisperse soot particles classified with the Differential Mobility Analyzers (DMA) were 30, 55, 90, 150, 250, 400, and 600 nm. A deposition chamber was designed to simulate the omni-directional flow condition around the tree leaves. Deposition velocities onto the needle-leaf trees were higher than those onto the broadleaf trees. P. densiflora showed the greatest deposition velocity, followed by T. cuspidata, Platanus occidentalis, Zelkova serrata, and Ginkgo biloba. In addition, from the comparison of deposition velocity between two groups of Platanus occidentalis leaves, i.e. one group of leaves with front sides only and the other with back sides only, it was supposed in case of the broadleaf trees that the removal of airborne soot particles of submicron and ultrafine sizes could be affected by the surface roughness of tree leaves, i.e. the veins and other structures on the leaves.

  15. Ultrafine particle removal and ozone generation by in-duct electrostatic precipitators.

    PubMed

    Poppendieck, Dustin G; Rim, Donghyun; Persily, Andrew K

    2014-01-01

    Human exposure to airborne ultrafine particles (UFP, < 100 nm) has been shown to have adverse health effects and can be elevated in buildings. In-duct electrostatic precipitator filters (ESP) have been shown to be an effective particulate control device for reducing UFP concentrations (20-100 nm) in buildings, although they have the potential to increase indoor ozone concentrations. This study investigated residential ESP filters to reduce ultrafine particles between 4 to 15 nm and quantified the resulting ozone generation. In-duct ESPs were operated in the central air handling unit of a test house. Results for the two tested ESP brands indicate that removal efficiency of 8 to 14 nm particles was near zero and always less than 10% (± 15%), possibly due to particle generation or low charging efficiency. Adding a media filter downstream of the ESP increased the decay rate for particles in the same size range. Continuous operation of one brand of ESP raised indoor ozone concentrations to 77 ppbv and 20 ppbv for a second brand. Using commercial filters containing activated carbon downstream of the installed ESP reduced the indoor steady-state ozone concentrations between 6% and 39%.

  16. Ultrahigh-vacuum furnace for sintering studies of ultrafine ceramic particles

    SciTech Connect

    Bonevich, J.E.; Teng, M.; Johnson, D.L.; Marks, L.D. )

    1991-12-01

    An ultrahigh-vacuum (UHV) furnace has been designed and constructed for the purpose of investigating the sintering behavior of ultrafine ceramic particles. The UHV furnace has three main chambers for particle production, sintering, and collection with additional facilities for an UHV transfer system. The furnace system achieves a base pressure of 4 {times} 10{sup {minus}7} Pa through the use of turbomolecular and ion pumps. The ultrafine particles of aluminum oxide are produced by the arc discharge method resulting in the formation of highly faceted particles in the size range of 20--50 nm. The particles are then carried into the tube furnace by a flowing gas stream where they sinter at elevated temperatures. The sintered samples are collected onto a specimen cartridge which is then transported under vacuum conditions to an UHV high-resolution electron microscope for structural characterization. The unique feature of this UHV furnace system is that one is able to perform sintering studies in a clean environment thereby minimizing the influence of contaminating species on the sintering behavior.

  17. Ultrahigh-vacuum furnace for sintering studies of ultrafine ceramic particles

    NASA Astrophysics Data System (ADS)

    Bonevich, John E.; Teng, Mao-Hua; Johnson, D. Lynn; Marks, Laurence D.

    1991-12-01

    An ultrahigh-vacuum (UHV) furnace has been designed and constructed for the purpose of investigating the sintering behavior of ultrafine ceramic particles. The UHV furnace has three main chambers for particle production, sintering, and collection with additional facilities for an UHV transfer system. The furnace system achieves a base pressure of 4 × 10-7 Pa through the use of turbomolecular and ion pumps. The ultrafine particles of aluminum oxide are produced by the arc discharge method resulting in the formation of highly faceted particles in the size range of 20-50 nm. The particles are then carried into the tube furnace by a flowing gas stream where they sinter at elevated temperatures. The sintered samples are collected onto a specimen cartridge which is then transported under vacuum conditions to an UHV high-resolution electron microscope for structural characterization. The unique feature of this UHV furnace system is that one is able to perform sintering studies in a clean environment thereby minimizing the influence of contaminating species on the sintering behavior.

  18. ULTRAFINE PARTICLE DISPOSITION IN THE HEALTHY AND MILDLY OBSTRUCTED LUNG

    EPA Science Inventory

    ABSTRACT
    We have shown previously that EGF receptor signaling is triggered by metals associated with ambient air particles. Specifically, we demonstrated that As, Zn and V activated the EGF receptor tyrosine kinase and the downstream kinases, MEK1/2 and ERK1/2. In this study, ...

  19. Empirical estimates of size-resolved precipitation scavenging coefficients for ultrafine particles

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Joerger, V. M.; Sullivan, R. C.

    2016-10-01

    Below-cloud scavenging coefficients for ultrafine particles (UFP) exhibit comparatively large uncertainties in part because of the limited availability of observational data sets from which robust parameterizations can be derived or that can be used to evaluate output from numerical models. Long time series of measured near-surface UFP size distributions and precipitation intensity from the Midwestern USA are used here to explore uncertainties in scavenging coefficients and test both the generalizability of a previous empirical parameterization developed using similar data from a boreal forest in Finland (Laakso et al., 2003) and whether a more parsimonious formulation can be developed. Scavenging coefficients (λ) over an ensemble of 95 rain events (with a median intensity of 1.56 mm h-1) and 104 particle diameter (Dp) classes (from 10 to 400 nm) indicate a mean value of 3.4 × 10-5 s-1 (with a standard error of 1.1 × 10-6 s-1) and a median of 1.9 × 10-5 s-1 (interquartile range: -2.0 × 10-5 to 7.5 × 10-5 s-1). The median scavenging coefficients for Dp: 10-400 nm computed over all 95 rain events exhibit close agreement with the empirical parameterization proposed by (Laakso et al., 2003). They decline from ∼4.1 × 10-5 s-1 for Dp of 10-19 nm, to ∼1.6 × 10-5 s-1 for Dp of 80-113 nm, and show an increasing tendency for Dp > 200 nm.

  20. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    SciTech Connect

    James K. Neathery; Gary Jacobs; Amitava Sarkar; Adam Crawford; Burtron H. Davis

    2006-09-30

    In the previous reporting period, modifications were completed for integrating a continuous wax filtration system for a 4 liter slurry bubble column reactor. During the current reporting period, a shakedown of the system was completed. Several problems were encountered with the progressive cavity pump used to circulate the wax/catalyst slurry though the cross-flow filter element and reactor. During the activation of the catalyst with elevated temperature (> 270 C) the elastomer pump stator released sulfur thereby totally deactivating the iron-based catalyst. Difficulties in maintaining an acceptable leak rate from the pump seal and stator housing were also encountered. Consequently, the system leak rate exceeded the expected production rate of wax; therefore, no online filtration could be accomplished. Work continued regarding the characterization of ultra-fine catalyst structures. The effect of carbidation on the morphology of iron hydroxide oxide particles was the focus of the study during this reporting period. Oxidation of Fe (II) sulfate results in predominantly {gamma}-FeOOH particles which have a rod-shaped (nano-needles) crystalline structure. Carbidation of the prepared {gamma}-FeOOH with CO at atmospheric pressure produced iron carbides with spherical layered structure. HRTEM and EDS analysis revealed that carbidation of {gamma}-FeOOH particles changes the initial nano-needles morphology and generates ultrafine carbide particles with irregular spherical shape.

  1. Ultrafine-grained mineralogy and matrix chemistry of olivine-rich chondritic interplanetary dust particles

    NASA Technical Reports Server (NTRS)

    Rietmeijer, F. J. M.

    1989-01-01

    Olivine-rich chondritic interplanetary dust particles (IDPs) are an important subset of fluffy chondritic IDPs collected in the earth's stratosphere. Particles in this subset are characterized by a matrix of nonporous, ultrafine-grained granular units. Euhedral single crystals, crystals fragments, and platey single crystals occur dispersed in the matrix. Analytical electron microscopy of granular units reveals predominant magnesium-rich olivines and FeNi-sulfides embedded in amorphous carbonaceous matrix material. The variable ratio of ultrafine-grained minerals vs. carbonaceous matrix material in granular units support variable C/Si ratios, and some fraction of sulfur is associated with carbonaceous matrix material. The high Mg/(Mg+Fe) ratios in granular units is similar to this distribution in P/Comet Halley dust. The chondritic composition of fine-grained, polycrystalline IDPs gradually breaks down into nonchondritic, and ultimately, single mineral compositions as a function of decreased particle mass. The relationship between particle mass and composition in the matrix of olivine-rich chondritic IDPs is comparable with the relationship inferred for P/Comet Halley dust.

  2. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    SciTech Connect

    Amitava Sarkar; James K. Neathery; Burtron H. Davis

    2006-12-31

    A fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of operation since the reaction is highly exothermic. Consequently, heavy wax products in one approach may be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase iron-based FTS and is a key factor for optimizing operating costs. The separation problem is further compounded by attrition of iron catalyst particles and the formation of ultra-fine particles.

  3. Children exposure to indoor ultrafine particles in urban and rural school environments.

    PubMed

    Cavaleiro Rufo, João; Madureira, Joana; Paciência, Inês; Slezakova, Klara; Pereira, Maria do Carmo; Aguiar, Lívia; Teixeira, João Paulo; Moreira, André; Oliveira Fernandes, Eduardo

    2016-07-01

    Extended exposure to ultrafine particles (UFPs) may lead to consequences in children due to their increased susceptibility when compared to older individuals. Since children spend in average 8 h/day in primary schools, assessing the number concentrations of UFPs in these institutions is important in order to evaluate the health risk for children in primary schools caused by indoor air pollution. Thus, the purpose of this study was to assess and determine the sources of indoor UFP number concentrations in urban and rural Portuguese primary schools. Indoor and outdoor ultrafine particle (UFP) number concentrations were measured in six urban schools (US) and two rural schools (RS) located in the north of Portugal, during the heating season. The mean number concentrations of indoor UFPs were significantly higher in urban schools than in rural ones (10.4 × 10(3) and 5.7 × 10(3) pt/cm(3), respectively). Higher UFP levels were associated with higher squared meters per student, floor levels closer to the ground, chalk boards, furniture or floor covering materials made of wood and windows with double-glazing. Indoor number concentrations of ultrafine-particles were inversely correlated with indoor CO2 levels. In the present work, indoor and outdoor concentrations of UFPs in public primary schools located in urban and rural areas were assessed, and the main sources were identified for each environment. The results not only showed that UFP pollution is present in augmented concentrations in US when compared to RS but also revealed some classroom/school characteristics that influence the concentrations of UFPs in primary schools.

  4. Fate and toxic effects of inhaled ultrafine cadmium oxide particles in the rat lung.

    PubMed

    Takenaka, S; Karg, E; Kreyling, W G; Lentner, B; Schulz, H; Ziesenis, A; Schramel, P; Heyder, J

    2004-01-01

    Female Fischer 344 rats were exposed to ultrafine cadmium oxide particles, generated by spark discharging, for 6 h at a concentration of 70 microg Cd/m(3) (1 x 10(6)/cm(3)) (40 nm modal diameter). Lung morphology and quantification of Cd content/concentration by inductively coupled plasma (ICP)-mass spectrometry were performed on days 0, 1, 4, and 7 after exposure. Cd content in the lung on day 0 was 0.53 +/- 0.12 microg/lung, corresponding to 19% of the estimated total inhaled cumulative dose, and the amount remained constant throughout the study. In the liver no significant increase of Cd content was found up to 4 days. A slight but statistically significant increase was observed in the liver on day 7. We found neither exposure-related morphological changes of lungs nor inflammatory responses in lavaged cells. Another group of rats were exposed to a higher concentration of ultrafine CdO particles (550 microg Cd/m(3) for 6 h, 51 nm modal diameter). The rats were sacrificed immediately and 1 day after exposure. The lavage study performed on day 0 showed an increase in the percentage of neutrophils. Multifocal alveolar inflammation was seen histologically on day 0 and day 1. Although the Cd content in the lung was comparable between day 0 and day 1 (3.9 microg/lung), significant elevation of Cd levels in the liver and kidneys was observed on both days. Two of 4 rats examined on day 0 showed elevation of blood cadmium, indicating systemic translocation of a fraction of deposited Cd from the lung in this group. These results and comparison with reported data using fine CdO particles indicate that inhalation of ultrafine CdO particles results in efficient deposition in the rat lung. With regard to the deposition dose, adverse health effects of ultrafine CdO and fine CdO appear to be comparable. Apparent systemic translocation of Cd took place only in animals exposed to a high concentration that induced lung injury.

  5. Ultrafine particle removal by residential heating, ventilating, and air-conditioning filters.

    PubMed

    Stephens, B; Siegel, J A

    2013-12-01

    This work uses an in situ filter test method to measure the size-resolved removal efficiency of indoor-generated ultrafine particles (approximately 7-100 nm) for six new commercially available filters installed in a recirculating heating, ventilating, and air-conditioning (HVAC) system in an unoccupied test house. The fibrous HVAC filters were previously rated by the manufacturers according to ASHRAE Standard 52.2 and ranged from shallow (2.5 cm) fiberglass panel filters (MERV 4) to deep-bed (12.7 cm) electrostatically charged synthetic media filters (MERV 16). Measured removal efficiency ranged from 0 to 10% for most ultrafine particles (UFP) sizes with the lowest rated filters (MERV 4 and 6) to 60-80% for most UFP sizes with the highest rated filter (MERV 16). The deeper bed filters generally achieved higher removal efficiencies than the panel filters, while maintaining a low pressure drop and higher airflow rate in the operating HVAC system. Assuming constant efficiency, a modeling effort using these measured values for new filters and other inputs from real buildings shows that MERV 13-16 filters could reduce the indoor proportion of outdoor UFPs (in the absence of indoor sources) by as much as a factor of 2-3 in a typical single-family residence relative to the lowest efficiency filters, depending in part on particle size.

  6. Characteristics of airborne ultrafine and coarse particles during the Australian dust storm of 23 September 2009

    NASA Astrophysics Data System (ADS)

    Jayaratne, E. R.; Johnson, G. R.; McGarry, P.; Cheung, H. C.; Morawska, L.

    2011-08-01

    Particle number concentrations and size distributions, visibility and particulate mass concentrations and weather parameters were monitored in Brisbane, Australia, on 23 September 2009, during the passage of a dust storm that originated 1400 km away in the dry continental interior. The dust concentration peaked at about mid-day when the hourly average PM 2.5 and PM 10 values reached 814 and 6460 μg m -3, respectively, with a sharp drop in atmospheric visibility. A linear regression analysis showed a good correlation between the coefficient of light scattering by particles (Bsp) and both PM 10 and PM 2.5. The particle number in the size range 0.5-20 μm exhibited a lognormal size distribution with modal and geometrical mean diameters of 1.6 and 1.9 μm, respectively. The modal mass was around 10 μm with less than 10% of the mass carried by particles smaller than 2.5 μm. The PM 10 fraction accounted for about 68% of the total mass. By mid-day, as the dust began to increase sharply, the ultrafine particle number concentration fell from about 6 × 10 3 cm -3 to 3 × 10 3 cm -3 and then continued to decrease to less than 1 × 10 3 cm -3 by 14 h, showing a power-law decrease with Bsp with an R2 value of 0.77 ( p < 0.01). Ultrafine particle size distributions also showed a significant decrease in number during the dust storm. This is the first scientific study of particle size distributions in an Australian dust storm.

  7. Measurements of Ultra-fine and Fine Aerosol Particles over Siberia: Large-scale Airborne Campaigns

    NASA Astrophysics Data System (ADS)

    Arshinov, Mikhail; Paris, Jean-Daniel; Stohl, Andreas; Belan, Boris; Ciais, Philippe; Nédélec, Philippe

    2010-05-01

    In this paper we discuss the results of in-situ measurements of ultra-fine and fine aerosol particles carried out in the troposphere from 500 to 7000 m in the framework of several International and Russian State Projects. Number concentrations of ultra-fine and fine aerosol particles measured during intensive airborne campaigns are presented. Measurements carried over a great part of Siberia were focused on particles with diameters from 3 to 21 nm to study new particle formation in the free/upper troposphere over middle and high latitudes of Asia, which is the most unexplored region of the Northern Hemisphere. Joint International airborne surveys were performed along the following routes: Novosibirsk-Salekhard-Khatanga-Chokurdakh-Pevek-Yakutsk-Mirny-Novosibirsk (YAK-AEROSIB/PLARCAT2008 Project) and Novosibirsk-Mirny-Yakutsk-Lensk-Bratsk-Novosibirsk (YAK-AEROSIB Project). The flights over Lake Baikal was conducted under Russian State contract. Concentrations of ultra-fine and fine particles were measured with automated diffusion battery (ADB, designed by ICKC SB RAS, Novosibirsk, Russia) modified for airborne applications. The airborne ADB coupled with CPC has an additional aspiration unit to compensate ambient pressure and changing flow rate. It enabled to classify nanoparticles in three size ranges: 3-6 nm, 6-21 nm, and 21-200 nm. To identify new particle formation events we used similar specific criteria as Young et al. (2007): (1) N3-6nm >10 cm-3, (2) R1=N3-6/N621 >1 and R2=N321/N21200 >0.5. So when one of the ratios R1 or R2 tends to decrease to the above limits the new particle formation is weakened. It is very important to notice that space scale where new particle formation was observed is rather large. All the events revealed in the FT occurred under clean air conditions (low CO mixing ratios). Measurements carried out in the atmospheric boundary layer over Baikal Lake did not reveal any event of new particle formation. Concentrations of ultra-fine

  8. Exposure assessment in Beijing, China: biological agents, ultrafine particles, and lead.

    PubMed

    Dong, Shuofei; Yao, Maosheng

    2010-11-01

    In this study, air samples were taken using a BioSampler and gelatin filters from six sites in Beijing: office, hospital, student dormitory, train station, subway, and a commercial street. Dust samples were also collected using a surface sampler from the same environments. Limulus amoebocyte lysate (LAL) and Glucatell assays were used to quantify sample endotoxin and (1,3)-β-d-glucan concentration levels, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to measure the dust mite allergens (Der p 1 and Der f 1). Ultrafine particle and lead concentrations in these sampling sites were also measured using P-Trak and atomic absorption spectrometer, respectively. Analysis of variance (ANOVA) and linear regression analysis were used to analyze the concentration data. Higher culturable bacteria (12,639 CFU/m3) and fungi (1,806 CFU/m3) concentrations were observed for the train station and the subway system, respectively. For the rest of sampling sites, their concentrations were comparable to those found in western countries, ranging from 990 to 2,276 CFU/m3 for bacteria, and from 119 to 269 CFU/m3 for fungi. ANOVA analysis indicated that there were statistically significant differences between the culturable bacterial and fungal concentration levels obtained for different sites (p value=0.0001 and 0.0047). As for dust allergens, endotoxin, and (1,3)-β-D-glucan, their concentrations also seemed to be comparable to those found in the developed countries. Airborne allergen concentrations ranged from 16 to 68 ng/m3. The dust-borne allergen concentration was observed to range from 0.063 to 0.327 ng/mg. As for endotoxin, the highest airborne concentration of 25.24 ng/m3 was observed for the commercial street, and others ranged from 0.0427 to 0.1259 ng/m3. And dust-borne endotoxin concentration ranged from 58.83 to 6,427.4 ng/mg. For (1,3)-β-D-glucan, the airborne concentration ranged from 0.02 to 1.2 ng/m3. Linear regression analyses showed that there existed

  9. Multi-metric measurement of personal exposure to ultrafine particles in selected urban microenvironments

    NASA Astrophysics Data System (ADS)

    Spinazzè, Andrea; Cattaneo, Andrea; Scocca, Damiano R.; Bonzini, Matteo; Cavallo, Domenico M.

    2015-06-01

    At the beginning of the study, our hypothesis was that visiting certain microenvironments (MEs) is one of the most important determinants of personal exposure to ultrafine particles (UFP) and that moving between microenvironments significantly differentiates exposure. The overall aim of this study is to perform relevant exposure measurements to extend our knowledge on environmental exposure to UFP in urban environments. The UFP concentrations in different urban MEs were measured by personal monitoring in repeated sampling campaigns along a fixed route. The measurement runs were performed on one-week periods and at different times of day (AM: 08.00-10.30; PM: 16.00-18.30) and repeated in different periods of the year (winter, spring, summer, and autumn) for a total of 56 runs (>110 h). Measurements included on-line monitoring of the UFP particle number concentration (PNC), mean diameter (mean-d) and lung-deposited surface-area (LDSA). Additionally, the PNC, particle mass concentration (PMC) profiles for quasi-ultrafine particles (QUFP; PM0.25) were estimated. A significant seasonal difference in the PNC and PMC, mean diameter and surface area was observed as well as between different times of the day and days of the week. In addition, differences in the UFP concentrations were also found in each ME, and there were specific mean-diameter and surface area concentrations. In general, the mean particle diameters showed an inverse relationship with the PNC, while the LDSA had the opposite behaviour. Appreciable differences among all MEs and monitoring periods were observed; the concentration patterns and variations seemed related to the typical sources of urban pollutants (traffic), proximity to sources and time of day. The highest exposures were observed for walking or biking along high-trafficked routes and while using public buses. The UFP exposure levels in modern cars, equipped with high-efficiency filters and in air recirculation mode, were significantly lower.

  10. Ultrafine Particles from Traffic Emissions and Children’s Health (UPTECH) in Brisbane, Queensland (Australia): Study Design and Implementation

    PubMed Central

    Ezz, Wafaa Nabil; Mazaheri, Mandana; Robinson, Paul; Johnson, Graham R.; Clifford, Samuel; He, Congrong; Morawska, Lidia; Marks, Guy B.

    2015-01-01

    Ultrafine particles are particles that are less than 0.1 micrometres (µm) in diameter. Due to their very small size they can penetrate deep into the lungs, and potentially cause more damage than larger particles. The Ultrafine Particles from Traffic Emissions and Children’s Health (UPTECH) study is the first Australian epidemiological study to assess the health effects of ultrafine particles on children’s health in general and peripheral airways in particular. The study is being conducted in Brisbane, Australia. Continuous indoor and outdoor air pollution monitoring was conducted within each of the twenty five participating school campuses to measure particulate matter, including in the ultrafine size range, and gases. Respiratory health effects were evaluated by conducting the following tests on participating children at each school: spirometry, forced oscillation technique (FOT) and multiple breath nitrogen washout test (MBNW) (to assess airway function), fraction of exhaled nitric oxide (FeNO, to assess airway inflammation), blood cotinine levels (to assess exposure to second-hand tobacco smoke), and serum C-reactive protein (CRP) levels (to measure systemic inflammation). A pilot study was conducted prior to commencing the main study to assess the feasibility and reliably of measurement of some of the clinical tests that have been proposed for the main study. Air pollutant exposure measurements were not included in the pilot study. PMID:25648226

  11. [Study on number concentration distribution of atmospheric ultrafine particles in Hangzhou].

    PubMed

    Xie, Xiao-Fang; Sun, Zai; Fu, Zhi-Min; Yang, Wen-Jun; Lin, Jian-Zhong

    2013-02-01

    Atmospheric ultrafine particles (UFPs) were measured with fast mobility particle sizer(FMPS) in Hangzhou, during March 2011 to February 2012. The number concentration and size distribution of UFPs associated with meteorology were studied. The results showed that the number concentration of UFPs was logarithmic bi-modal distribution, and the seasonal levels presented winter > summer > spring> autumn. The highest monthly average concentration was 3.56 x 10(4) cm-3 in December and the lowest was 2.51 x 10(4) cm-3 in October. The seasonal values of count medium diameter(CMD) were spring > winter > autumn > summer. The highest monthly average CMD was 53. 51 nm in April and the lowest was 16.68 nm in June. Meteorological factors had effects on concentration of UFPs.

  12. Exposure to ultrafine particles in hospitality venues with partial smoking bans.

    PubMed

    Neuberger, Manfred; Moshammer, Hanns; Schietz, Armin

    2013-01-01

    Fine particles in hospitality venues with insufficient smoking bans indicate health risks from passive smoking. In a random sample of Viennese inns (restaurants, cafes, bars, pubs and discotheques) effects of partial smoking bans on indoor air quality were examined by measurement of count, size and chargeable surface of ultrafine particles (UFPs) sized 10-300 nm, simultaneously with mass of particles sized 300-2500 nm (PM2.5). Air samples were taken in 134 rooms unannounced during busy hours and analyzed by a diffusion size classifier and an optical particle counter. Highest number concentrations of particles were found in smoking venues and smoking rooms (median 66,011 pt/cm(3)). Even non-smoking rooms adjacent to smoking rooms were highly contaminated (median 25,973 pt/cm(3)), compared with non-smoking venues (median 7408 pt/cm(3)). The particle number concentration was significantly correlated with the fine particle mass (P<0.001). We conclude that the existing tobacco law in Austria is ineffective to protect customers in non-smoking rooms of hospitality premises. Health protection of non-smoking guests and employees from risky UFP concentration is insufficient, even in rooms labeled "non-smoking". Partial smoking bans with separation of smoking rooms failed.

  13. Local lung deposition of ultrafine particles in healthy adults: experimental results and theoretical predictions

    PubMed Central

    2016-01-01

    Background Ultrafine particles (UFP) of biogenic and anthropogenic origin occur in high numbers in the ambient atmosphere. In addition, aerosols containing ultrafine powders are used for the inhalation therapy of various diseases. All these facts make it necessary to obtain comprehensive knowledge regarding the exact behavior of UFP in the respiratory tract. Methods Theoretical simulations of local UFP deposition are based on previously conducted inhalation experiments, where particles with various sizes (0.04, 0.06, 0.08, and 0.10 µm) were administered to the respiratory tract by application of the aerosol bolus technique. By the sequential change of the lung penetration depth of the inspired bolus, different volumetric lung regions could be generated and particle deposition in these regions could be evaluated. The model presented in this contribution adopted all parameters used in the experiments. Besides the obligatory comparison between practical and theoretical data, also advanced modeling predictions including the effect of varying functional residual capacity (FRC) and respiratory flow rate were conducted. Results Validation of the UFP deposition model shows that highest deposition fractions occur in those volumetric lung regions corresponding to the small and partly alveolated airways of the tracheobronchial tree. Particle deposition proximal to the trachea is increased in female probands with respect to male subjects. Decrease of both the FRC and the respiratory flow rate results in an enhancement of UFP deposition. Conclusions The study comes to the conclusion that deposition of UFP taken up via bolus inhalation is influenced by a multitude of factors, among which lung morphometry and breathing conditions play a superior role. PMID:27942511

  14. ECG parameters and exposure to carbon ultrafine particles in young healthy subjects.

    PubMed

    Zareba, Wojciech; Couderc, Jean Philippe; Oberdörster, Günter; Chalupa, David; Cox, Christopher; Huang, Li-Shan; Peters, Annette; Utell, Mark J; Frampton, Mark W

    2009-02-01

    The mechanisms underlying the association between air pollution and cardiovascular morbidity and mortality are unknown. This study aimed to determine whether controlled exposure to elemental carbon ultrafine particles (UFP) affects electrocardiogram (ECG) parameters describing heart rate variability; repolarization duration, morphology, and variability; and changes in the ST segment. Two separate controlled studies (12 subjects each) were performed using a crossover design, in which each subject was exposed to filtered air and carbon UFP for 2 hours. The first protocol involved 2 exposures to air and 10 microg/m(3) (approximately 2 x 10(6) particles/cm(3), count median diameter approximately 25 nm, geometric standard deviation approximately 1.6), at rest. The second protocol included 3 exposures to air, 10, and 25 microg/m(3) UFP (approximately 7 x 10(6) particles/cm(3)), with repeated exercise. Each subject underwent a continuous digital 12-lead ECG Holter recording to analyze the above ECG parameters. Repeated measures analysis of variance (ANOVA) was used to compare tested parameters between exposures. The observed responses to UFP exposure were small and generally not significant, although there were trends indicating an increase in parasympathetic tone, which is most likely also responsible for trends toward ST elevation, blunted QTc shortening, and increased variability of T-wave complexity after exposure to UFP. Recovery from exercise showed a blunted response of the parasympathetic system after exposure to UFP in comparison to air exposure. In conclusion, transient exposure to 10-25 microg/m(3) ultrafine carbon particles does not cause marked changes in ECG-derived parameters in young healthy subjects. However, trends are observed indicating that some subjects might be susceptible to air pollution, with a response involving autonomic modulation of the heart and repolarization of the ventricular myocardium.

  15. CONTINUOUS MONITORING OF ULTRAFINE, FINE, AND COARSE PARTICLES IN A RESIDENCE FOR 18 MONTHS IN 1999-2000

    EPA Science Inventory

    Continuous monitors were employed for 18 months in an occupied townhouse to measure ultrafine, fine, and coarse particles; air change rates; wind speed and direction; temperature; and relative humidity (RH). A main objective was to document short-term and long-term variation in...

  16. Ultrafine particles near a major roadway in Raleigh, North Carolina: downwind attenuation and correlation with traffic-related pollutants

    EPA Science Inventory

    Ultrafine particles (UFPs, diameter <100 run) emitted by traffic are a potential direct health threat to nearby populations and may additionally act as a tracer for co-emitted pollutants. During summertime in Raleigh, North Carolina, UFPs were simultaneously measured upwind and d...

  17. STUDY OF ULTRAFINE PARTICLES NEAR A MAJOR HIGHWAY WITH HEAVY-DUTY DIESEL TRAFFIC. (R827352C011)

    EPA Science Inventory

    Motor vehicle emissions usually constitute the most significant source of ultrafine particles (diameter <0.1 small mu, Greekm) in an urban environment. Zhu et al. (J. Air Waste Manage. As...

  18. Chemical, dimensional and morphological ultrafine particle characterization from a waste-to-energy plant

    SciTech Connect

    Buonanno, Giorgio; Stabile, Luca; Avino, Pasquale; Belluso, Elena

    2011-11-15

    Highlights: > Particle size distributions and total concentrations measurement at the stack and before the fabric filter of an incinerator. > Chemical characterization of UFPs in terms of heavy metal concentration through a nuclear method. > Mineralogical investigation through a Transmission Electron Microscope equipped with an Energy Dispersive Spectrometer. > Heavy metal concentrations on UFPs as function of the boiling temperature. > Different mineralogical and morphological composition amongst samples collected before the fabric filter and at the stack. - Abstract: Waste combustion processes are responsible of particles and gaseous emissions. Referring to the particle emission, in the last years specific attention was paid to ultrafine particles (UFPs, diameter less than 0.1 {mu}m), mainly emitted by combustion processes. In fact, recent findings of toxicological and epidemiological studies indicate that fine and ultrafine particles could represent a risk for health and environment. Therefore, it is necessary to quantify particle emissions from incinerators also to perform an exposure assessment for the human populations living in their surrounding areas. To these purposes, in the present work an experimental campaign aimed to monitor UFPs was carried out at the incineration plant in San Vittore del Lazio (Italy). Particle size distributions and total concentrations were measured both at the stack and before the fabric filter inlet in order to evaluate the removal efficiency of the filter in terms of UFPs. A chemical characterization of UFPs in terms of heavy metal concentration was performed through a nuclear method, i.e. Instrumental Neutron Activation Analysis (INAA), as well as a mineralogical investigation was carried out through a Transmission Electron Microscope (TEM) equipped with an Energy Dispersive Spectrometer (EDS) in order to evaluate shape, crystalline state and mineral compound of sampled particles. Maximum values of 2.7 x 10{sup 7} part. cm

  19. Ultrafine particle size distributions near freeways: Effects of differing wind directions on exposure

    NASA Astrophysics Data System (ADS)

    Kozawa, Kathleen H.; Winer, Arthur M.; Fruin, Scott A.

    2012-12-01

    High ambient ultrafine particle (UFP) concentrations may play an important role in the adverse health effects associated with living near busy roadways. However, UFP size distributions change rapidly as vehicle emissions dilute and age. These size changes can influence UFP lung deposition rates and dose because deposition in the respiratory system is a strong function of particle size. Few studies to date have measured and characterized changes in near-road UFP size distributions in real-time, thus missing transient variations in size distribution due to short-term fluctuations in wind speed, direction, or particle dynamics. In this study we measured important wind direction effects on near-freeway UFP size distributions and gradients using a mobile platform with 5-s time resolution. Compared to more commonly measured perpendicular (downwind) conditions, parallel wind conditions appeared to promote formation of broader and larger size distributions of roughly one-half the particle concentration. Particles during more parallel wind conditions also changed less in size with downwind distance and the fraction of lung-deposited particle number was calculated to be 15% lower than for downwind conditions, giving a combined decrease of about 60%. In addition, a multivariate analysis of several variables found meteorology, particularly wind direction and temperature, to be important in predicting UFP concentrations within 150 m of a freeway (R2 = 0.46, p = 0.014).

  20. Ultrafine particle size distributions near freeways: Effects of differing wind directions on exposure.

    PubMed

    Kozawa, Kathleen H; Winer, Arthur M; Fruin, Scott A

    2012-12-01

    High ambient ultrafine particle (UFP) concentrations may play an important role in the adverse health effects associated with living near busy roadways. However, UFP size distributions change rapidly as vehicle emissions dilute and age. These size changes can influence UFP lung deposition rates and dose because deposition in the respiratory system is a strong function of particle size. Few studies to date have measured and characterized changes in near-road UFP size distributions in real-time, thus missing transient variations in size distribution due to short-term fluctuations in wind speed, direction, or particle dynamics. In this study we measured important wind direction effects on near-freeway UFP size distributions and gradients using a mobile platform with 5-s time resolution. Compared to more commonly measured perpendicular (downwind) conditions, parallel wind conditions appeared to promote formation of broader and larger size distributions of roughly one-half the particle concentration. Particles during more parallel wind conditions also changed less in size with downwind distance and the fraction of lung-deposited particle number was calculated to be 15% lower than for downwind conditions, giving a combined decrease of about 60%. In addition, a multivariate analysis of several variables found meteorology, particularly wind direction and temperature, to be important in predicting UFP concentrations within 150 m of a freeway (R(2) = 0.46, p = 0.014).

  1. Size-resolved respiratory-tract deposition of fine and ultrafine hydrophobic and hygroscopic aerosol particles during rest and exercise.

    PubMed

    Löndahl, Jakob; Massling, Andreas; Pagels, Joakim; Swietlicki, Erik; Vaclavik, Elvira; Loft, Steffen

    2007-02-01

    Airborne ultrafine particles (diameter <100 nm) are ubiquitous in the environment and have been associated with adverse health effects. The respiratory-tract deposition of these particles is fundamentally influenced by their hygroscopicity: their ability to grow by condensation of water in the humid respiratory system. Ambient particles are typically hygroscopic, to varying degrees. This article investigates the influence of hygroscopicity, exercise level, gender, and intersubject variability on size-dependent deposition of fine and ultrafine particles during spontaneous breathing. Using a novel and well-characterized setup, respiratory-tract deposition in the range 12-320 nm has been measured for 29 healthy adults (20 men, 9 women). Each subject completed four sessions: rest and light exercise on an ergometer bicycle while inhaling both hydrophobic (diethylhexylsebacate) and hygroscopic (NaCl) particles. The deposited fraction (DF) based on dry diameters was two to four times higher for the hydrophobic ultrafine particles than for the hygroscopic. The DF of hygroscopic ultrafine particles could be estimated by calculating their equilibrium size at 99.5% relative humidity. The differences in average DF due to exercise level and gender were essentially less than 0.03. However, the minute ventilation increased fourfold during exercise and was 18-46% higher for the men than for the women. Consequently the deposited dose of particles was fourfold higher during exercise and considerably increased for the male subjects. Some individuals consistently had a high DF in all four sessions. As an example, the results show that an average person exposed to 100-nm hydrophobic particles during exercise will receive a 16 times higher dose than a relaxed person exposed to an equal amount of hygroscopic (NaCl) particles.

  2. Ultrafine particles and nitrogen oxides generated by gas and electric cooking

    PubMed Central

    Dennekamp, M; Howarth, S; Dick, C; Cherrie, J; Donaldson, K; Seaton, A

    2001-01-01

    OBJECTIVES—To measure the concentrations of particles less than 100 nm diameter and of oxides of nitrogen generated by cooking with gas and electricity, to comment on possible hazards to health in poorly ventilated kitchens.
METHODS—Experiments with gas and electric rings, grills, and ovens were used to compare different cooking procedures. Nitrogen oxides (NOx) were measured by a chemiluminescent ML9841A NOx analyser. A TSI 3934 scanning mobility particle sizer was used to measure average number concentration and size distribution of aerosols in the size range 10-500 nm.
RESULTS—High concentrations of particles are generated by gas combustion, by frying, and by cooking of fatty foods. Electric rings and grills may also generate particles from their surfaces. In experiments where gas burning was the most important source of particles, most particles were in the size range 15-40 nm. When bacon was fried on the gas or electric rings the particles were of larger diameter, in the size range 50-100 nm. The smaller particles generated during experiments grew in size with time because of coagulation. Substantial concentrations of NOX were generated during cooking on gas; four rings for 15 minutes produced 5 minute peaks of about 1000 ppb nitrogen dioxide and about 2000 ppb nitric oxide.
CONCLUSIONS—Cooking in a poorly ventilated kitchen may give rise to potentially toxic concentrations of numbers of particles. Very high concentrations of oxides of nitrogen may also be generated by gas cooking, and with no extraction and poor ventilation, may reach concentrations at which adverse health effects may be expected. Although respiratory effects of exposure to NOx might be anticipated, recent epidemiology suggests that cardiac effects cannot be excluded, and further investigation of this is desirable.


Keywords: cooking fuels; nitrogen oxides; ultrafine particles PMID:11452045

  3. Real-time gaseous, PM and ultrafine particle emissions from a modern marine engine operating on biodiesel.

    PubMed

    Jayaram, Varalakshmi; Agrawal, Harshit; Welch, William A; Miller, J Wayne; Cocker, David R

    2011-03-15

    Emissions from harbor-craft significantly affect air quality in populated regions near ports and inland waterways. This research measured regulated and unregulated emissions from an in-use EPA Tier 2 marine propulsion engine on a ferry operating in a bay following standard methods. A special effort was made to monitor continuously both the total Particulate Mass (PM) mass emissions and the real-time Particle Size Distribution (PSD). The engine was operated following the loads in ISO 8178-4 E3 cycle for comparison with the certification standards and across biodiesel blends. Real-time measurements were also made during a typical cruise in the bay. Results showed the in-use nitrogen oxide (NOx) and PM(2.5) emission factors were within the not to exceed standard for Tier 2 marine engines. Comparing across fuels we observed the following: a) no statistically significant change in NO(x) emissions with biodiesel blends (B20, B50); b) ∼ 16% and ∼ 25% reduction of PM(2.5) mass emissions with B20 and B50 respectively; c) a larger organic carbon (OC) to elemental carbon (EC) ratio and organic mass (OM) to OC ratio with B50 compared to B20 and B0; d) a significant number of ultrafine nuclei and a smaller mass mean diameter with increasing blend-levels of biodiesel. The real-time monitoring of gaseous and particulate emissions during a typical cruise in the San Francisco Bay (in-use cycle) revealed important effects of ocean/bay currents on emissions: NO(x) and CO(2) increased 3-fold; PM(2.5) mass increased 6-fold; and ultrafine particles disappeared due to the effect of bay currents. This finding has implications on the use of certification values instead of actual in-use emission values when developing inventories. Emission factors for some volatile organic compounds (VOCs), carbonyls, and poly aromatic hydrocarbons (PAHs) are reported as supplemental data.

  4. Long-term characterization of indoor and outdoor ultrafine particles at a commercial building.

    PubMed

    Wang, Yungang; Hopke, Philip K; Chalupa, David C; Utell, Mark J

    2010-08-01

    The particle number concentrations in the size range of 10-500 nm were measured inside and outside of a commercial building in Rochester, New York from 2005 to 2009. The indoor ventilation conditions were controlled by a heating, ventilation, and air-conditioning (HVAC) system. The overall average indoor and outdoor particle number concentrations were 2166 cm(-3) and 5214 cm(-3), respectively. Comparison of the indoor and outdoor ultrafine particles (UFP) distributions revealed that indoor sources contributed to the indoor UFP concentrations. The indoor/outdoor (I/O) ratio generally increased with particle size. The I/O ratios in the summer months were higher than those in the winter months. Indoor and outdoor correlations of particle concentrations were slightly weaker in warmer months. These results indicated that changes in the air exchange rates (AER) may have affected the correlation between indoor and outdoor UFP number concentrations. Moreover, indoor activities such as food preparation and cleaning may have contributed to the indoor UFP number concentrations.

  5. Effects of Flow Velocity and Particle Size on Transport of Ultrafine Bubbles in Porous Media

    NASA Astrophysics Data System (ADS)

    Hamamoto, S.; Nihei, N.; Ueda, Y.; Nishimura, T.

    2015-12-01

    Potential applications of ultrafine bubbles (UFBs) have drawn more attention, especially in environmental engineering fields such as soil/groundwater remediation. Understanding a transport mechanism of UFBs in soils is essential to optimize remediation techniques using UFBs. In this study, column transport experiments using glass beads with different size fraction were conducted, where UFBs created by either air or oxygen were injected to the column with different flow conditions. Effects of particle size and flow velocities on transport characteristics of UFBs were investigated based on the column experiments. The results showed that attachments of UFBs were enhanced under lower water velocity condition, exhibiting more than 50% of UFBs injected were attached inside the column. The mobility of O2-UFBs which have lower zeta potential was higher than that of Air-UFBs. A convection-dispersion model including bubble attachment and detachment terms was applied to the obtained breakthrough curves for each experiment, showing good fitness against the measured data.

  6. Aerosol Measurements of the Fine and Ultrafine Particle Content of Lunar Regolith

    NASA Technical Reports Server (NTRS)

    Greenberg, Paul S.; Chen, Da-Ren; Smith, Sally A.

    2007-01-01

    We report the first quantitative measurements of the ultrafine (20 to 100 nm) and fine (100 nm to 20 m) particulate components of Lunar surface regolith. The measurements were performed by gas-phase dispersal of the samples, and analysis using aerosol diagnostic techniques. This approach makes no a priori assumptions about the particle size distribution function as required by ensemble optical scattering methods, and is independent of refractive index and density. The method provides direct evaluation of effective transport diameters, in contrast to indirect scattering techniques or size information derived from two-dimensional projections of high magnification-images. The results demonstrate considerable populations in these size regimes. In light of the numerous difficulties attributed to dust exposure during the Apollo program, this outcome is of significant importance to the design of mitigation technologies for future Lunar exploration.

  7. Measurement of ultrafine particle size distributions from coal-, oil-, and gas-fired stationary combustion sources.

    PubMed

    Chang, M C Oliver; Chow, Judith C; Watson, John G; Hopke, Philip K; Yi, Seung-Muk; England, Glenn C

    2004-12-01

    first 10 sec after dilution but shows only minor differences between 10 and 80 sec. The lifetimes of the ultrafine particles are relatively short, with a scale on the order of a few seconds. Results from this study suggest that an aging time of 10 sec and a dilution air ratio of 20 are sufficient to obtain representative primary particle emission samples from stationary combustion sources.

  8. Soft-X-Ray-Enhanced Electrostatic Precipitation for Protection against Inhalable Allergens, Ultrafine Particles, and Microbial Infections

    PubMed Central

    Kettleson, Eric M.; Schriewer, Jill M.; Buller, R. Mark L.

    2013-01-01

    Protection of the human lung from infectious agents, allergens, and ultrafine particles is difficult with current technologies. High-efficiency particulate air (HEPA) filters remove airborne particles of >0.3 μm with 99.97% efficiency, but they are expensive to maintain. Electrostatic precipitation has been used as an inexpensive approach to remove large particles from airflows, but it has a collection efficiency minimum in the submicrometer size range, allowing for a penetration window for some allergens and ultrafine particles. Incorporating soft X-ray irradiation as an in situ component of the electrostatic precipitation process greatly improves capture efficiency of ultrafine particles. Here we demonstrate the removal and inactivation capabilities of soft-X-ray-enhanced electrostatic precipitation technology targeting infectious agents (Bacillus anthracis, Mycobacterium bovis BCG, and poxviruses), allergens, and ultrafine particles. Incorporation of in situ soft X-ray irradiation at low-intensity corona conditions resulted in (i) 2-fold to 9-fold increase in capture efficiency of 200- to 600-nm particles and (ii) a considerable delay in the mean day of death as well as lower overall mortality rates in ectromelia virus (ECTV) cohorts. At the high-intensity corona conditions, nearly complete protection from viral and bacterial respiratory infection was afforded to the murine models for all biological agents tested. When optimized for combined efficient particle removal with limited ozone production, this technology could be incorporated into stand-alone indoor air cleaners or scaled for installation in aircraft cabin, office, and residential heating, ventilating, and air-conditioning (HVAC) systems. PMID:23263945

  9. Performance of school bus retrofit systems: ultrafine particles and other vehicular pollutants.

    PubMed

    Zhang, Qunfang; Zhu, Yifang

    2011-08-01

    This study evaluated the performance of retrofit systems for diesel-powered school buses, a diesel oxidation catalyst (DOC) muffler and a spiracle crankcase filtration system (CFS), regarding ultrafine particles (UFPs) and other air pollutants from tailpipe emissions and inside bus cabins. Tailpipe emissions and in-cabin air pollutant levels were measured before and after retrofitting when the buses were idling and during actual pick-up/drop off routes. Retrofit systems significantly reduced tailpipe emissions with a reduction of 20-94% of total particles with both DOC and CFS installed. However, no unequivocal decrease was observed for in-cabin air pollutants after retrofitting. The AC/fan unit and the surrounding air pollutant concentrations played more important roles for determining the in-cabin air quality of school buses than did retrofit technologies. Although current retrofit systems reduce children's exposure while waiting to board at a bus station, retrofitting by itself does not protect children satisfactorily from in-cabin particle exposures. Turning on the bus engine increased in-cabin UFP levels significantly only when the wind blew from the bus' tailpipe toward its hood with its windows open. This indicated that wind direction and window position are significant factors determining how much self-released tailpipe emissions may penetrate into the bus cabin. The use of an air purifier was found to remove in-cabin particles by up to 50% which might be an alternative short-to-medium term strategy to protect children's health.

  10. Effects of combustion-derived ultrafine particles and manufactured nanoparticles on heart cells in vitro.

    PubMed

    Helfenstein, Maria; Miragoli, Michele; Rohr, Stephan; Müller, Loretta; Wick, Peter; Mohr, Martin; Gehr, Peter; Rothen-Rutishauser, Barbara

    2008-11-20

    Evidence from epidemiological studies indicates that acute exposure to airborne pollutants is associated with an increased risk of morbidity and mortality attributed to cardiovascular diseases. The present study investigated the effects of combustion-derived ultrafine particles (diesel exhaust particles) as well as engineered nanoparticles (titanium dioxide and single-walled carbon nanotubes) on impulse conduction characteristics, myofibrillar structure and the formation of reactive oxygen species in patterned growth strands of neonatal rat ventricular cardiomyocytes in vitro. Diesel exhaust particles as well as titanium dioxide nanoparticles showed the most pronounced effects. We observed a dose-dependent change in heart cell function, an increase in reactive oxygen species and, for titanium dioxide, we also found a less organized myofibrillar structure. The mildest effects were observed for single-walled carbon nanotubes, for which no clear dose-dependent alterations of theta and dV/dt(max) could be determined. In addition, there was no increase in oxidative stress and no change in the myofibrillar structure. These results suggest that diesel exhaust as well as titanium dioxide particles and to a lesser extent also single-walled carbon nanotubes can directly induce cardiac cell damage and can affect the function of the cells.

  11. Vascular Effects of Ultrafine Particles in Persons with Type 2 Diabetes

    PubMed Central

    Stewart, Judith C.; Chalupa, David C.; Devlin, Robert B.; Frasier, Lauren M.; Huang, Li-Shan; Little, Erika L.; Lee, Steven M.; Phipps, Richard P.; Pietropaoli, Anthony P.; Taubman, Mark B.; Utell, Mark J.; Frampton, Mark W.

    2010-01-01

    Background Diabetes confers an increased risk for cardiovascular effects of airborne particles. Objective We hypothesized that inhalation of elemental carbon ultrafine particles (UFP) would activate blood platelets and vascular endothelium in people with type 2 diabetes. Methods In a randomized, double-blind, crossover trial, 19 subjects with type 2 diabetes inhaled filtered air or 50 μg/m3 elemental carbon UFP (count median diameter, 32 nm) by mouthpiece for 2 hr at rest. We repeatedly measured markers of vascular activation, coagulation, and systemic inflammation before and after exposure. Results Compared with air, particle exposure increased platelet expression of CD40 ligand (CD40L) and the number of platelet-leukocyte conjugates 3.5 hr after exposure. Soluble CD40L decreased with UFP exposure. Plasma von Willebrand factor increased immediately after exposure. There were no effects of particles on plasma tissue factor, coagulation factors VII or IX, or D-dimer. Conclusions Inhalation of elemental carbon UFP for 2-hr transiently activated platelets, and possibly the vascular endothelium, in people with type 2 diabetes. PMID:20822968

  12. Personal exposure to airborne ultrafine particles in the urban area of Milan

    NASA Astrophysics Data System (ADS)

    Cattaneo, A.; Garramone, G.; Taronna, M.; Peruzzo, C.; Cavallo, D. M.

    2009-02-01

    The relevance of health effects related to ultrafine particles (UFPs; aerodynamic diameter < 100 nm) can be better evaluated using high-resolution strategies for measuring particle number concentrations. In this study, two different portable Condensation Particle Counters (CPCs) were used to measure personal exposure to UFPs in the central area of Milan for one week period during spring, with three sampling sessions per day. Experimental data were continuously collected along an established urban pathway, moving afoot or by different private and public means of transport. Correlation analysis between data measured by two CPCs was performed and general results showed a good agreement, especially at concentrations lower than 2×105 particles /cm3. UFPs measures were divided on the basis of crossed environments or micro-environments, days of the week and day time (hours). The highest measured mean concentrations and data variability were observed during walking time and moving on motorized vehicles (bus and car), indicating that the highest exposure to UFPs can be reached near motorized traffic. The lowest exposures were observed in green areas and in office microenvironments. An appreciable difference between working and non-working days was observed. Concentration patterns and variation by days of the week and time periods appears related to time trends in traffic intensity.

  13. Comparison of Three Real-Time Measurement Methods for Airborne Ultrafine Particles in the Silicon Alloy Industry.

    PubMed

    Kero, Ida Teresia; Jørgensen, Rikke Bramming

    2016-09-01

    The aim of this study was to compare the applicability and the correlation between three commercially available instruments capable of detection, quantification, and characterization of ultrafine airborne particulate matter in the industrial setting of a tapping area in a silicon alloy production plant. The number concentration of ultrafine particles was evaluated using an Electric Low Pressure Impactor (ELPI(TM)), a Fast Mobility Particle Sizer (FMPS(TM)), and a Condensation Particle Counter (CPC). The results are discussed in terms of particle size distribution and temporal variations linked to process operations. The instruments show excellent temporal covariation and the correlation between the FMPS and ELPI is good. The advantage of the FMPS is the excellent time- and size resolution of the results. The main advantage of the ELPI is the possibility to collect size-fractionated samples of the dust for subsequent analysis by, for example, electron microscopy. The CPC does not provide information about the particle size distribution and its correlation to the other two instruments is somewhat poor. Nonetheless, the CPC gives basic, real-time information about the ultrafine particle concentration and can therefore be used for source identification.

  14. ¹¹¹Indium-labeled ultrafine carbon particles; a novel aerosol for pulmonary deposition and retention studies.

    PubMed

    Sanchez-Crespo, Alejandro; Klepczynska-Nyström, Anna; Lundin, Anders; Larsson, Britt Marie; Svartengren, Magnus

    2011-02-01

    Continuous environmental or occupational exposure to airborne particulate pollution is believed to be a major hazard for human health. A technique to characterize their deposition and clearance from the lungs is fundamental to understand the underlying mechanisms behind their negative health effects. In this work, we describe a method for production and follow up of ultrafine carbon particles labeled with radioactive ¹¹¹Indium (¹¹¹In). The physicochemical and biological properties of the aerosol are described in terms of particle size and concentration, agglomeration rate, chemical bonding stability, and human lung deposition and retention. Preliminary in vivo data from a healthy human pilot exposure and 1-week follow up of the aerosol is presented. More than 98% of the generated aerosol was labeled with Indium and with particle sizes log normally distributed around 79  nm count median diameter. The aerosol showed good generation reproducibility and chemical stability, about 5% leaching 7 days after generation. During human inhalation, the particles were deposited in the alveolar space, with no central airways involvement. Seven days after exposure, the cumulative activity retention was 95.3%. Activity leaching tests from blood and urine samples confirmed that the observed clearance was explained by unbound activity, suggesting that there was no significant elimination of ultrafine particles. Compared to previously presented methods based on Technegas, ¹¹¹In-labelled ultrafine carbon particles allow for extended follow-up assessments of particulate pollution retention in healthy and diseased lungs.

  15. Comparison of Three Real-Time Measurement Methods for Airborne Ultrafine Particles in the Silicon Alloy Industry

    PubMed Central

    Kero, Ida Teresia; Jørgensen, Rikke Bramming

    2016-01-01

    The aim of this study was to compare the applicability and the correlation between three commercially available instruments capable of detection, quantification, and characterization of ultrafine airborne particulate matter in the industrial setting of a tapping area in a silicon alloy production plant. The number concentration of ultrafine particles was evaluated using an Electric Low Pressure Impactor (ELPITM), a Fast Mobility Particle Sizer (FMPSTM), and a Condensation Particle Counter (CPC). The results are discussed in terms of particle size distribution and temporal variations linked to process operations. The instruments show excellent temporal covariation and the correlation between the FMPS and ELPI is good. The advantage of the FMPS is the excellent time- and size resolution of the results. The main advantage of the ELPI is the possibility to collect size-fractionated samples of the dust for subsequent analysis by, for example, electron microscopy. The CPC does not provide information about the particle size distribution and its correlation to the other two instruments is somewhat poor. Nonetheless, the CPC gives basic, real-time information about the ultrafine particle concentration and can therefore be used for source identification. PMID:27598180

  16. Exposure to ultrafine particles and PM 2.5 in four Sydney transport modes

    NASA Astrophysics Data System (ADS)

    Knibbs, Luke D.; de Dear, Richard J.

    2010-08-01

    Concentrations of ultrafine (<0.1 μm) particles (UFPs) and PM 2.5 (<2.5 μm) were measured whilst commuting along a similar route by train, bus, ferry and automobile in Sydney, Australia. One trip on each transport mode was undertaken during both morning and evening peak hours throughout a working week, for a total of 40 trips. Analyses comprised one-way ANOVA to compare overall (i.e. all trips combined) geometric mean concentrations of both particle fractions measured across transport modes, and assessment of both the correlation between wind speed and individual trip means of UFPs and PM 2.5, and the correlation between the two particle fractions. Overall geometric mean concentrations of UFPs and PM 2.5 ranged from 2.8 (train) to 8.4 (bus) × 10 4 particles cm -3 and 22.6 (automobile) to 29.6 (bus) μg m -3, respectively, and a statistically significant difference ( p < 0.001) between modes was found for both particle fractions. Individual trip geometric mean concentrations were between 9.7 × 10 3 (train) and 2.2 × 10 5 (bus) particles cm -3 and 9.5 (train) to 78.7 (train) μg m -3. Estimated commuter exposures were variable, and the highest return trip mean PM 2.5 exposure occurred in the ferry mode, whilst the highest UFP exposure occurred during bus trips. The correlation between fractions was generally poor, and in keeping with the duality of particle mass and number emissions in vehicle-dominated urban areas. Wind speed was negatively correlated with, and a generally poor determinant of, UFP and PM 2.5 concentrations, suggesting a more significant role for other factors in determining commuter exposure.

  17. Environmentally persistent free radicals amplify ultrafine particle mediated cellular oxidative stress and cytotoxicity

    PubMed Central

    Balakrishna, Shrilatha; Lomnicki, Slawo; McAvey, Kevin M; Cole, Richard B; Dellinger, Barry; Cormier, Stephania A

    2009-01-01

    Background Combustion generated particulate matter is deposited in the respiratory tract and pose a hazard to the lungs through their potential to cause oxidative stress and inflammation. We have previously shown that combustion of fuels and chlorinated hydrocarbons produce semiquinone-type radicals that are stabilized on particle surfaces (i.e. environmentally persistent free radicals; EPFRs). Because the composition and properties of actual combustion-generated particles are complex, heterogeneous in origin, and vary from day-to-day, we have chosen to use surrogate particle systems. In particular, we have chosen to use the radical of 2-monochlorophenol (MCP230) as the EPFR because we have previously shown that it forms a EPFR on Cu(II)O surfaces and catalyzes formation of PCDD/F. To understand the physicochemical properties responsible for the adverse pulmonary effects of combustion by-products, we have exposed human bronchial epithelial cells (BEAS-2B) to MCP230 or the CuO/silica substrate. Our general hypothesis was that the EPFR-containing particle would have greater toxicity than the substrate species. Results Exposure of BEAS-2B cells to our combustion generated particle systems significantly increased reactive oxygen species (ROS) generation and decreased cellular antioxidants resulting in cell death. Resveratrol treatment reversed the decline in cellular glutathione (GSH), glutathione peroxidase (GPx), and superoxide dismutase (SOD) levels for both types of combustion-generated particle systems. Conclusion The enhanced cytotoxicity upon exposure to MCP230 correlated with its ability to generate more cellular oxidative stress and concurrently reduce the antioxidant defenses of the epithelial cells (i.e. reduced GSH, SOD activity, and GPx). The EPFRs in MCP230 also seem to be of greater biological concern due to their ability to induce lipid peroxidation. These results are consistent with the oxidizing nature of the CuO/silica ultrafine particles and the

  18. Respiratory Health Effects of Ultrafine Particles in Children: A Literature Review

    PubMed Central

    Heinzerling, Amy; Hsu, Joy; Yip, Fuyuen

    2015-01-01

    By convention, airborne particles ≤0.1 μm (100 nm) are defined as ultrafine particles (UFPs). UFPs can comprise a large number of particles in particulate matter with aerodynamic diameters ≤2.5 μm (PM2.5). Despite the documented respiratory health effects of PM2.5 and concerns that UFPs might be more toxic than larger particular matter, the effects of UFPs on the respiratory system are not well-described. Even less is known about the respiratory health effects of UFPs among particularly vulnerable populations including children. We reviewed studies examining respiratory health effects of UFPs in children and identified 12 relevant articles. Most (8/12) studies measured UFP exposure using central ambient monitors, and we found substantial heterogeneity in UFP definitions and study designs. No long-term studies were identified. In single pollutant models, UFPs were associated with incident wheezing, current asthma, lower spirometric values, and asthma-related emergency department visits among children. Also, higher exhaled nitric oxide levels were positively correlated with UFP dose among children with asthma or allergy to house dust mites in 1 study. Multivariate models accounting for potential co-pollutant confounding yielded no statistically significant results. Although evidence for a relationship between UFPs and children's respiratory is accumulating, the literature remains inconclusive. Interpretation of existing data is constrained by study heterogeneity, limited accounting for UFP spatial variation, and lack of significant findings from multi-pollutant models. PMID:26783373

  19. Effect of time-activity adjustment on exposure assessment for traffic-related ultrafine particles.

    PubMed

    Lane, Kevin J; Levy, Jonathan I; Scammell, Madeleine Kangsen; Patton, Allison P; Durant, John L; Mwamburi, Mkaya; Zamore, Wig; Brugge, Doug

    2015-01-01

    Exposures to ultrafine particles (<100 nm, estimated as particle number concentration, PNC) differ from ambient concentrations because of the spatial and temporal variability of both PNC and people. Our goal was to evaluate the influence of time-activity adjustment on exposure assignment and associations with blood biomarkers for a near-highway population. A regression model based on mobile monitoring and spatial and temporal variables was used to generate hourly ambient residential PNC for a full year for a subset of participants (n=140) in the Community Assessment of Freeway Exposure and Health study. We modified the ambient estimates for each hour using personal estimates of hourly time spent in five micro-environments (inside home, outside home, at work, commuting, other) as well as particle infiltration. Time-activity adjusted (TAA)-PNC values differed from residential ambient annual average (RAA)-PNC, with lower exposures predicted for participants who spent more time away from home. Employment status and distance to highway had a differential effect on TAA-PNC. We found associations of RAA-PNC with high sensitivity C-reactive protein and Interleukin-6, although exposure-response functions were non-monotonic. TAA-PNC associations had larger effect estimates and linear exposure-response functions. Our findings suggest that time-activity adjustment improves exposure assessment for air pollutants that vary greatly in space and time.

  20. Simulation on a novel micron-array inertial impactor for submicron and ultrafine particle separation

    NASA Astrophysics Data System (ADS)

    Liu, Rui-Tao; Tao, Lu-Qi; Yang, Yi; Ren, Tian-Ling

    2016-08-01

    The particulate matter (PM), which was put forward in 1997 by US, had taken more and more attention due to the influence on human health. Although the mass concentration, number concentration and chemical composition of PM were still major research directions, how to collect these PMs more efficiently becomes critical. Inertial impactor is an effective separation device, however, due to different motion states of PM2.5 and PM0.3 in the flow field, the inertial impactor which can separate PM0.3 from other PMs has not been fabricated. In this work, the motion states for both submicron and ultrafine particles were studied by using classical theory of channel aerodynamic, and a novel micron-array inertial impactor was designed and simulated for the first time. Besides, the influence of some characteristic parameters (W, T, S, Dc, etc.) on particle collection efficiency were researched and discussed through simulation results. This novel structure can be easily fabricated by MEMS technology or laser direct writing and also can be widely used in particle separation or flexible sensor fields.

  1. Ultrafine particles formed by heating droplets of simulated ash containing metals

    SciTech Connect

    Carbone, F.; Barone, A.; Pagliara, R.; Beretta, F.; D'Anna, A.; D'Alessio, A.

    2008-12-15

    Coal and biomass combustion and waste incineration produce inorganic aerosol, whose ultrafine fraction is hypothesized to be generated mainly by metal vaporization and subsequent nucleation and growth in a high-temperature atmosphere. To investigate this mechanism, we investigated nanoparticle inception and early growth processes at high temperature by spraying monodisperse droplets of simulated ash containing metals in the centerline of a laboratory ethylene/air laminar premixed flame at stoichiometric conditions. Particles were collected by thermophoresis on mica substrates for atomic force microscopy dimensional and morphological analysis. Chemical nature, volume fraction, and mean diameter of particles were evaluated by in situ UV-Vis broadband light absorption and laser light-scattering measurements. We also measured size distribution of material sampled from the flame without dilution using differential mobility analysis and scanning electron microscopy. Energy dispersive X-ray spectroscopy provided further information on the chemical composition of particles deposited on substrates. Size distributions showed that the flame-generated aerosol have a high number concentration, are mostly smaller than 10 nm, and persist far downstream of the droplet injection point. Preliminary results showed that the coagulation rate of those nanoparticles is much slower than their collision rate, which implies that their lifetime may be long and may represent a severe problem for environmental pollution.

  2. Effect of time-activity adjustment on exposure assessment for traffic-related ultrafine particles

    PubMed Central

    Lane, Kevin J; Levy, Jonathan I; Scammell, Madeleine Kangsen; Patton, Allison P; Durant, John L; Mwamburi, Mkaya; Zamore, Wig; Brugge, Doug

    2015-01-01

    Exposures to ultrafine particles (<100 nm, estimated as particle number concentration, PNC) differ from ambient concentrations because of the spatial and temporal variability of both PNC and people. Our goal was to evaluate the influence of time-activity adjustment on exposure assignment and associations with blood biomarkers for a near-highway population. A regression model based on mobile monitoring and spatial and temporal variables was used to generate hourly ambient residential PNC for a full year for a subset of participants (n=140) in the Community Assessment of Freeway Exposure and Health study. We modified the ambient estimates for each hour using personal estimates of hourly time spent in five micro-environments (inside home, outside home, at work, commuting, other) as well as particle infiltration. Time-activity adjusted (TAA)-PNC values differed from residential ambient annual average (RAA)-PNC, with lower exposures predicted for participants who spent more time away from home. Employment status and distance to highway had a differential effect on TAA-PNC. We found associations of RAA-PNC with high sensitivity C-reactive protein and Interleukin-6, although exposure-response functions were non-monotonic. TAA-PNC associations had larger effect estimates and linear exposure-response functions. Our findings suggest that time-activity adjustment improves exposure assessment for air pollutants that vary greatly in space and time. PMID:25827314

  3. Electrosurgical Smoke: Ultrafine Particle Measurements and Work Environment Quality in Different Operating Theatres.

    PubMed

    Romano, Francesco; Gustén, Jan; De Antonellis, Stefano; Joppolo, Cesare M

    2017-01-30

    Air cleanliness in operating theatres (OTs) is an important factor for preserving the health of both the patient and the medical staff. Particle contamination in OTs depends mainly on the surgery process, ventilation principle, personnel clothing systems and working routines. In many open surgical operations, electrosurgical tools (ESTs) are used for tissue cauterization. ESTs generate a significant airborne contamination, as surgical smoke. Surgical smoke is a work environment quality problem. Ordinary surgical masks and OT ventilation systems are inadequate to control this problem. This research work is based on numerous monitoring campaigns of ultrafine particle concentrations in OTs, equipped with upward displacement ventilation or with a downward unidirectional airflow system. Measurements performed during ten real surgeries highlight that the use of ESTs generates a quite sharp and relevant increase of particle concentration in the surgical area as well within the entire OT area. The measured contamination level in the OTs are linked to surgical operation, ventilation principle, and ESTs used. A better knowledge of airborne contamination is crucial for limiting the personnel's exposure to surgical smoke. Research results highlight that downward unidirectional OTs can give better conditions for adequate ventilation and contaminant removal performances than OTs equipped with upward displacement ventilation systems.

  4. Electrosurgical Smoke: Ultrafine Particle Measurements and Work Environment Quality in Different Operating Theatres

    PubMed Central

    Romano, Francesco; Gustén, Jan; De Antonellis, Stefano; Joppolo, Cesare M.

    2017-01-01

    Air cleanliness in operating theatres (OTs) is an important factor for preserving the health of both the patient and the medical staff. Particle contamination in OTs depends mainly on the surgery process, ventilation principle, personnel clothing systems and working routines. In many open surgical operations, electrosurgical tools (ESTs) are used for tissue cauterization. ESTs generate a significant airborne contamination, as surgical smoke. Surgical smoke is a work environment quality problem. Ordinary surgical masks and OT ventilation systems are inadequate to control this problem. This research work is based on numerous monitoring campaigns of ultrafine particle concentrations in OTs, equipped with upward displacement ventilation or with a downward unidirectional airflow system. Measurements performed during ten real surgeries highlight that the use of ESTs generates a quite sharp and relevant increase of particle concentration in the surgical area as well within the entire OT area. The measured contamination level in the OTs are linked to surgical operation, ventilation principle, and ESTs used. A better knowledge of airborne contamination is crucial for limiting the personnel’s exposure to surgical smoke. Research results highlight that downward unidirectional OTs can give better conditions for adequate ventilation and contaminant removal performances than OTs equipped with upward displacement ventilation systems. PMID:28146089

  5. The rural carbonaceous aerosols in coarse, fine, and ultrafine particles during haze pollution in northwestern China.

    PubMed

    Zhu, Chong-Shu; Cao, Jun-Ji; Tsai, Chuen-Jinn; Shen, Zhen-Xing; Liu, Sui-Xin; Huang, Ru-Jin; Zhang, Ning-ning; Wang, Ping

    2016-03-01

    The carbonaceous aerosol concentrations in coarse particle (PM10: Dp ≤ 10 μm, particulate matter with an aerodynamic diameter less than 10 μm), fine particle (PM2.5: Dp ≤ 2.5 μm), and ultrafine particle (PM0.133: Dp ≤ 0.133 μm) carbon fractions in a rural area were investigated during haze events in northwestern China. The results indicated that PM2.5 contributed a large fraction in PM10. OC (organic carbon) accounted for 33, 41, and 62 % of PM10, PM2.5, and PM0.133, and those were 2, 2.4, and 0.4 % for EC (elemental carbon) in a rural area, respectively. OC3 was more abundant than other organic carbon fractions in three PMs, and char dominated EC in PM10 and PM2.5 while soot dominated EC in PM0.133. The present study inferred that K(+), OP, and OC3 are good biomass burning tracers for rural PM10 and PM2.5, but not for PM0.133 during haze pollution. Our results suggest that biomass burning is likely to be an important contributor to rural PMs in northwestern China. It is necessary to establish biomass burning control policies for the mitigation of severe haze pollution in a rural area.

  6. Combustion of PTFE: The Effects of Gravity and Pigmentation on Ultrafine Particle Generation

    NASA Technical Reports Server (NTRS)

    McKinnon, J. Thomas; Srivastava, Rajiv; Todd, Paul

    1997-01-01

    Ultrafine particles generated during polymer thermodegradation are a major health hazard, owing to their unique pathway of processing in the lung. This hazard in manned spacecraft is poorly understood, because the particulate products of polymer thermodegradation are generated under low gravity conditions. Particulate generated from the degradation of PolyTetraFluoroEthylene (PTFE), insulation coating for 20 AWG copper wire (representative of spacecraft application) under intense ohmic heating were studied in terrestrial gravity and microgravity. Microgravity tests were done in a 1.2-second drop tower at the Colorado School of Mines (CSM). Thermophoretic sampling was used for particulate collection. Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) were used to examine the smoke particulates. Image software was used to calculate particle size distribution. In addition to gravity, the color of PTFE insulation has an overwhelming effect on size, shape and morphology of the particulate. Nanometer-sized primary particles were found in all cases, and aggregation and size distribution was dependent on both color and gravity; higher aggregation occurred in low gravity. Particulates from white, black, red and yellow colored PTFE insulations were studied. Elemental analysis of the particulates shows the presence of inorganic pigments.

  7. Alterations in welding process voltage affect the generation of ultrafine particles, fume composition, and pulmonary toxicity.

    PubMed

    Antonini, James M; Keane, Michael; Chen, Bean T; Stone, Samuel; Roberts, Jenny R; Schwegler-Berry, Diane; Andrews, Ronnee N; Frazer, David G; Sriram, Krishnan

    2011-12-01

    The goal was to determine if increasing welding voltage changes the physico-chemical properties of the fume and influences lung responses. Rats inhaled 40 mg/m³ (3 h/day × 3 days) of stainless steel (SS) welding fume generated at a standard voltage setting of 25 V (regular SS) or at a higher voltage (high voltage SS) of 30 V. Particle morphology, size and composition were characterized. Bronchoalveolar lavage was performed at different times after exposures to assess lung injury. Fumes collected from either of the welding conditions appeared as chain-like agglomerates of nanometer-sized primary particles. High voltage SS welding produced a greater number of ultrafine-sized particles. Fume generated by high voltage SS welding was higher in manganese. Pulmonary toxicity was more substantial and persisted longer after exposure to the regular SS fume. In summary, a modest raise in welding voltage affected fume size and elemental composition and altered the temporal lung toxicity profile.

  8. Size-Resolved Source Emission Rates of Indoor Ultrafine Particles Considering Coagulation.

    PubMed

    Rim, Donghyun; Choi, Jung-Il; Wallace, Lance A

    2016-09-20

    Indoor ultrafine particles (UFP, <100 nm) released from combustion and consumer products lead to elevated human exposure to UFP. UFP emitted from the sources undergo aerosol transformation processes such as coagulation and deposition. The coagulation effect can be significant during the source emission due to high concentration and high mobility of nanosize particles. However, few studies have estimated size-resolved UFP source emission strengths while considering coagulation in their theoretical and experimental research work. The primary objective of this study is to characterize UFP source strength by considering coagulation in addition to other indoor processes (i.e., deposition and ventilation) in a realistic setting. A secondary objective is to test a hypothesis that size-resolved UFP source emission rates are unimodal and log-normally distributed for three common indoor UFP sources: an electric stove, a natural gas burner, and a paraffin wax candle. Experimental investigations were performed in a full-scale test building. Size- and time-resolved concentrations of UFP ranging from 2 to 100 nm were monitored using a scanning mobility particle sizer (SMPS). Based on the temporal evolution of the particle size distribution during the source emission period, the size-dependent source emission rate was determined using a material-balance modeling approach. The results indicate that, for a given UFP source, the source strength varies with particle size and source type. The analytical model assuming a log-normally distributed source emission rate could predict the temporal evolution of the particle size distribution with reasonable accuracy for the gas stove and the candle. Including the effect of coagulation was found to increase the estimates of source strengths by up to a factor of 8. This result implies that previous studies on indoor UFP source strengths considering only deposition and ventilation might have largely underestimated the true values of UFP source

  9. Aerosol-computational fluid dynamics modeling of ultrafine and black carbon particle emission, dilution, and growth near roadways

    NASA Astrophysics Data System (ADS)

    Huang, L.; Gong, S. L.; Gordon, M.; Liggio, J.; Staebler, R.; Stroud, C. A.; Lu, G.; Mihele, C.; Brook, J. R.; Jia, C. Q.

    2014-12-01

    Many studies have shown that on-road vehicle emissions are the dominant source of ultrafine particles (UFPs; diameter < 100 nm) in urban areas and near-roadway environments. In order to advance our knowledge on the complex interactions and competition among atmospheric dilution, dispersion, and dynamics of UFPs, an aerosol dynamics-computational fluid dynamics (CFD) coupled model is developed and validated against field measurements. A unique approach of applying periodic boundary conditions is proposed to model pollutant dispersion and dynamics in one unified domain from the tailpipe level to the ambient near-road environment. This approach significantly reduces the size of the computational domain, and therefore allows fast simulation of multiple scenarios. The model is validated against measured turbulent kinetic energy (TKE) and horizontal gradient of pollution concentrations perpendicular to a major highway. Through a model sensitivity analysis, the relative importance of individual aerosol dynamical processes on the total particle number concentration (N) and particle number-size distribution (PSD) near a highway is investigated. The results demonstrate that (1) coagulation has a negligible effect on N and particle growth, (2) binary homogeneous nucleation (BHN) of H2SO4-H2O is likely responsible for elevated N closest to the road, and (3) N and particle growth are very sensitive to the condensation of semi-volatile organics (SVOCs), particle dry deposition, and the interaction between these processes. The results also indicate that, without the proper treatment of the atmospheric boundary layer (i.e., its wind profile and turbulence quantities), the nucleation rate would be underestimated by a factor of 5 in the vehicle wake region due to overestimated dilution. Therefore, introducing atmospheric boundary layer (ABL) conditions to activity-based emission models may potentially improve their performance in estimating UFP traffic emissions.

  10. GENE PROFILING AND THE ROLE OF COAGULATION FACTORS IN INFLAMMATION SIGNALING IN HUMAN PULMONARY ARTERY ENDOTHELIAL CELLS FOLLOWING ULTRAFINE PARTICLES EXPOUSRE

    EPA Science Inventory

    Epidemiologic studies have linked exposures to particulate air pollution and increased cardiovascular mortality and morbidity, however, the mechanisms are not clear. Ultrafine particles within air pollution represent a particular area of concern because the small size fraction o...

  11. Lung cancer risk in relation to traffic-related nano/ultrafine particle-bound PAHs exposure: a preliminary probabilistic assessment.

    PubMed

    Liao, Chung-Min; Chio, Chia-Pin; Chen, Wei-Yu; Ju, Yun-Ru; Li, Wen-Hsuan; Cheng, Yi-Hsien; Liao, Vivian Hsiu-Chuan; Chen, Szu-Chieh; Ling, Min-Pei

    2011-06-15

    Exposures to carcinogenic polycyclic aromatic hydrocarbons (PAHs) have been linked to human lung cancer. The purpose of this study was to assess lung cancer risk caused by inhalation exposure to nano/ultrafine particle-bound PAHs at the population level in Taiwan appraised with recent published data. A human respiratory tract model was linked with a physiologically based pharmacokinetic model to estimate deposition fraction and internal organic-specific PAHs doses. A probabilistic risk assessment framework was developed to estimate potential lung cancer risk. We reanalyzed particle size distribution, total-PAHs, particle-bound benzo(a)pyrene (B[a]P) and PM concentrations. A dose-response profile describing the relationships between external B[a]P concentration and lung cancer risk response was constructed based on population attributable fraction (PAF). We found that 90% probability lung cancer risks ranged from 10(-5) to 10(-4) for traffic-related nano and ultrafine particle-bound PAHs, indicating a potential lung cancer risk. The particle size-specific PAF-based excess annual lung cancer incidence rate due to PAHs exposure was estimated to be less than 1 per 100,000 population, indicating a mild risk factor for lung cancer. We concluded that probabilistic risk assessment linked PAF for limiting cumulative PAHs emissions to reduce lung cancer risk plays a prominent role in future government risk assessment program.

  12. Comparison of daytime and nighttime concentration profiles and size distributions of ultrafine particles near a major highway.

    PubMed

    Zhu, Yifang; Kuhn, Thomas; Mayo, Paul; Hinds, William C

    2006-04-15

    Previously we have conducted systematic measurements of the concentration and size distribution of ultrafine particles in the vicinity of major highways during daytime in Los Angeles. The present study compares these with similar measurements made at night. Particle number concentration was measured by a condensation particle counter (CPC) and size distributions in the size range from 7 to 300 nm were measured by a scanning mobility particle sizer (SMPS). Measurements were taken at 30, 60, 90, 150, and 300 m upwind and downwind from the center of the 1-405 freeway. Average traffic flow at night was about 25% of that observed during the day. Particle number concentration measured at 30 m downwind from the freeway was 80% of previous daytime measurements. This discrepancy between changes in traffic counts and particle number concentrations is apparently due to the decreased temperature, increased relative humidity, and lower wind speed at night. Particle size distributions do not change as dramatically as they did during the daytime. Particle number concentration decays exponentially downwind from the freeway similarly to what was observed during the day, but at a slower rate. No particle number concentration gradient has been observed for the upwind side of the freeway. No PM2.5 and very weak PM10 concentration gradients were observed downwind of thefreeway at night. Ultrafine particle number concentration measured at 300 m downwind from the freeway was still distinguishably higher than upwind background concentration at night. These data may be used to help estimate exposure to ultrafine particles in the vicinity of major highways for epidemiology studies.

  13. Ultrafine Angelica gigas powder normalizes ovarian hormone levels and has antiosteoporosis properties in ovariectomized rats: particle size effect.

    PubMed

    Choi, Kyeong-Ok; Lee, Inae; Paik, Sae-Yeol-Rim; Kim, Dong Eun; Lim, Jung Dae; Kang, Wie-Soo; Ko, Sanghoon

    2012-10-01

    The root of Angelica gigas (Korean angelica) is traditionally used to treat women's ailments that are caused by an impairment of menstrual blood flow and cycle irregularities. This study evaluated the effect particle size of Korean angelica powder on its efficacy for treating estrogen-related symptoms of menopause. Initially, Korean angelica roots were pulverized into ultrafine powder, and orally administered to the rats at a concentration of 500 mg/kg body weight for 8 weeks. The effects of Korean angelica powder particle size on extraction yield, contents of bioactive compounds (decursin and decursinol angelate), levels of serum ovarian hormones (estradiol and progesterone), reproductive hormones (luteinizing hormone and follicle-stimulating hormone), and experimental osteoporosis parameters (mineral density, strength, and histological features) were determined. A significant increase (fivefold) in the contents of decursin and decursinol angelate in the extract of the ultrafine Korean angelica powder was observed compared to coarse Korean angelica powder. Rats were divided into sham-operated or ovariectomized (OVX) groups that were fed coarse (CRS) or ultrafine (UF) ground Korean angelica root. The serum levels of estradiol in the OVX_UF group were 19.2% and 54.1% higher than that of OVX_CRS group. Serum bone-alkaline phosphatase/total-alkaline phosphatase index in the OVX_UF group was half that of the OVX_CRS group. In addition, less trabecular bone loss and thick cortical areas were observed in rats administered ultrafine powder. Therefore, ultrafine grinding may enhance the bioactivity of herbal medicines and be especially useful when their extracted forms lose bioactivity during processing, storage, and oral intake.

  14. Ultrafine Angelica gigas Powder Normalizes Ovarian Hormone Levels and Has Antiosteoporosis Properties in Ovariectomized Rats: Particle Size Effect

    PubMed Central

    Choi, Kyeong-Ok; Lee, Inae; Paik, Sae-Yeol-Rim; Kim, Dong Eun; Lim, Jung Dae; Kang, Wie-Soo; Ko, Sanghoon

    2012-01-01

    Abstract The root of Angelica gigas (Korean angelica) is traditionally used to treat women's ailments that are caused by an impairment of menstrual blood flow and cycle irregularities. This study evaluated the effect particle size of Korean angelica powder on its efficacy for treating estrogen-related symptoms of menopause. Initially, Korean angelica roots were pulverized into ultrafine powder, and orally administered to the rats at a concentration of 500 mg/kg body weight for 8 weeks. The effects of Korean angelica powder particle size on extraction yield, contents of bioactive compounds (decursin and decursinol angelate), levels of serum ovarian hormones (estradiol and progesterone), reproductive hormones (luteinizing hormone and follicle-stimulating hormone), and experimental osteoporosis parameters (mineral density, strength, and histological features) were determined. A significant increase (fivefold) in the contents of decursin and decursinol angelate in the extract of the ultrafine Korean angelica powder was observed compared to coarse Korean angelica powder. Rats were divided into sham-operated or ovariectomized (OVX) groups that were fed coarse (CRS) or ultrafine (UF) ground Korean angelica root. The serum levels of estradiol in the OVX_UF group were 19.2% and 54.1% higher than that of OVX_CRS group. Serum bone-alkaline phosphatase/total-alkaline phosphatase index in the OVX_UF group was half that of the OVX_CRS group. In addition, less trabecular bone loss and thick cortical areas were observed in rats administered ultrafine powder. Therefore, ultrafine grinding may enhance the bioactivity of herbal medicines and be especially useful when their extracted forms lose bioactivity during processing, storage, and oral intake. PMID:23039111

  15. Production of Ultrafine, High-purity Ceramic Powders Using the US Bureau of Mines Developed Turbomill

    NASA Technical Reports Server (NTRS)

    Hoyer, Jesse L.

    1993-01-01

    Turbomilling, an innovative grinding technology developed by the U.S. Bureau of Mines in the early 1960's for delaminating filler-grade kaolinitic clays, has been expanded into the areas of particle size reduction, material mixing, and process reaction kinetics. The turbomill, originally called an attrition grinder, has been used for particle size reduction of many minerals, including natural and synthetic mica, pyrophyllite, talc, and marble. In recent years, an all-polymer version of the turbomill has been used to produce ultrafine, high-purity, advanced ceramic powders such as SiC, Si3N4, TiB2, and ZrO2. In addition to particle size reduction, the turbomill has been used to produce intimate mixtures of high surface area powders and whiskers. Raw materials, TiN, AlN, and Al2O3, used to produce a titanium nitride/aluminum oxynitride (TiN/AlON) composite, were mixed in the turbomill, resulting in strength increases over samples prepared by dry ball milling. Using the turbomill as a leach vessel, it was found that 90.4 pct of the copper was extracted from the chalcopyrite during a 4-hour leach test in ferric sulfate versus conventional processing which involves either roasting of the ore for Cu recovery or leaching of the ore for several days.

  16. The effects of vegetation barriers on near-road ultrafine particle number and carbon monoxide concentrations.

    PubMed

    Lin, Ming-Yeng; Hagler, Gayle; Baldauf, Richard; Isakov, Vlad; Lin, Hong-Yiou; Khlystov, Andrey

    2016-05-15

    Numerous studies have shown that people living in near-roadway communities (within 100 m of the road) are exposed to high ultrafine particle (UFP) number concentrations, which may be associated with adverse health effects. Vegetation barriers have been shown to affect pollutant transport via particle deposition to leaves and altering the dispersion of emission plumes, which in turn would modify the exposure of near-roadway communities to traffic-related UFPs. In this study, both stationary (equipped with a Scanning Mobility Particle Sizer, SMPS) and mobile (equipped with Fast Mobility Particle Sizer, FMPS) measurements were conducted to investigate the effects of vegetation barriers on downwind UFP (particle diameters ranging from 14 to 102 nm) concentrations at two sites in North Carolina, USA. One site had mainly deciduous vegetation while the other was primarily coniferous; both sites have a nearby open field without the vegetation barriers along the same stretch of limited access road, which served as a reference. During downwind conditions (traffic emissions transported towards the vegetation barrier) and when the wind speed was above or equal to 0.5m/s, field measurements indicated that vegetation barriers with full foliage reduced UFP and CO concentrations by 37.7-63.6% and 23.6-56.1%, respectively. When the test was repeated at the same sites during winter periods when deciduous foliage was reduced, the deciduous barrier during winter showed no significant change in UFP concentration before and after the barrier. Results from the stationary (using SMPS) and mobile (using FMPS) measurements for UFP total number concentrations generally agreed to within 20%.

  17. Children exposure assessment to ultrafine particles and black carbon: The role of transport and cooking activities

    NASA Astrophysics Data System (ADS)

    Buonanno, G.; Stabile, L.; Morawska, L.; Russi, A.

    2013-11-01

    An accurate evaluation of the airborne particle dose-response relationship requires detailed measurements of the actual particle concentration levels that people are exposed to, in every microenvironment in which they reside. The aim of this work was to perform an exposure assessment of children in relation to two different aerosol species: ultrafine particles (UFPs) and black carbon (BC). To this purpose, personal exposure measurements, in terms of UFP and BC concentrations, were performed on 103 children aged 8-11 years (10.1 ± 1.1 years) using hand-held particle counters and aethalometers. Simultaneously, a time-activity diary and a portable GPS were used to determine the children's daily time-activity pattern and estimate their inhaled dose of UFPs and BC. The median concentration to which the study population was exposed was found to be comparable to the high levels typically detected in urban traffic microenvironments, in terms of both particle number (2.2 × 104 part. cm-3) and BC (3.8 μg m-3) concentrations. Daily inhaled doses were also found to be relatively high and were equal to 3.35 × 1011 part. day-1 and 3.92 × 101 μg day-1 for UFPs and BC, respectively. Cooking and using transportation were recognized as the main activities contributing to overall daily exposure, when normalized according to their corresponding time contribution for UFPs and BC, respectively. Therefore, UFPs and BC could represent tracers of children exposure to particulate pollution from indoor cooking activities and transportation microenvironments, respectively.

  18. Estimates of HVAC filtration efficiency for fine and ultrafine particles of outdoor origin

    NASA Astrophysics Data System (ADS)

    Azimi, Parham; Zhao, Dan; Stephens, Brent

    2014-12-01

    This work uses 194 outdoor particle size distributions (PSDs) from the literature to estimate single-pass heating, ventilating, and air-conditioning (HVAC) filter removal efficiencies for PM2.5 and ultrafine particles (UFPs: <100 nm) of outdoor origin. The PSDs were first fitted to tri-modal lognormal distributions and then mapped to size-resolved particle removal efficiency of a wide range of HVAC filters identified in the literature. Filters included those with a minimum efficiency reporting value (MERV) of 5, 6, 7, 8, 10, 12, 14, and 16, as well as HEPA filters. We demonstrate that although the MERV metric defined in ASHRAE Standard 52.2 does not explicitly account for UFP or PM2.5 removal efficiency, estimates of filtration efficiency for both size fractions increased with increasing MERV. Our results also indicate that outdoor PSD characteristics and assumptions for particle density and typical size-resolved infiltration factors (in the absence of HVAC filtration) do not drastically impact estimates of HVAC filter removal efficiencies for PM2.5. The impact of these factors is greater for UFPs; however, they are also somewhat predictable. Despite these findings, our results also suggest that MERV alone cannot always be used to predict UFP or PM2.5 removal efficiency given the various size-resolved removal efficiencies of different makes and models, particularly for MERV 7 and MERV 12 filters. This information improves knowledge of how the MERV designation relates to PM2.5 and UFP removal efficiency for indoor particles of outdoor origin. Results can be used to simplify indoor air quality modeling efforts and inform standards and guidelines.

  19. Filter performance of n99 and n95 facepiece respirators against viruses and ultrafine particles.

    PubMed

    Eninger, Robert M; Honda, Takeshi; Adhikari, Atin; Heinonen-Tanski, Helvi; Reponen, Tiina; Grinshpun, Sergey A

    2008-07-01

    The performance of three filtering facepiece respirators (two models of N99 and one N95) challenged with an inert aerosol (NaCl) and three virus aerosols (enterobacteriophages MS2 and T4 and Bacillus subtilis phage)-all with significant ultrafine components-was examined using a manikin-based protocol with respirators sealed on manikins. Three inhalation flow rates, 30, 85, and 150 l min(-1), were tested. The filter penetration and the quality factor were determined. Between-respirator and within-respirator comparisons of penetration values were performed. At the most penetrating particle size (MPPS), >3% of MS2 virions penetrated through filters of both N99 models at an inhalation flow rate of 85 l min(-1). Inhalation airflow had a significant effect upon particle penetration through the tested respirator filters. The filter quality factor was found suitable for making relative performance comparisons. The MPPS for challenge aerosols was <0.1 mum in electrical mobility diameter for all tested respirators. Mean particle penetration (by count) was significantly increased when the size fraction of <0.1 mum was included as compared to particles >0.1 mum. The filtration performance of the N95 respirator approached that of the two models of N99 over the range of particle sizes tested ( approximately 0.02 to 0.5 mum). Filter penetration of the tested biological aerosols did not exceed that of inert NaCl aerosol. The results suggest that inert NaCl aerosols may generally be appropriate for modeling filter penetration of similarly sized virions.

  20. Continuous Near-Road Monitoring of Ultrafine Particles from 2010-2015 in Toronto, Canada

    NASA Astrophysics Data System (ADS)

    Su, Y.; Sofowote, U.; Debosz, J.; Munoz, T.

    2015-12-01

    Ultrafine particles (UFPs) have an aerodynamic diameter less than 100 nanometre (nm). Their large surface areas per unit mass favor absorption of toxic chemicals in air. UFPs could penetrate deep into the respiratory or cardiovascular systems and pose adverse health effects. Recent studies showed the association between children exposure to UFPs and their systolic blood pressure. In urban environments, primary sources of UFPs are from road traffic emissions and account for most of the total particle numbers. Controls on UPFs rely on better understanding of their emission sources and environmental behaviour. Ontario Ministry of the Environment and Climate Change have monitored UFPs since 2010 at two near-road stations in Toronto by using TSI 3031 UFP monitors. One station is located in mixed residential and industrial area and 16 meters from a major road with over 20,000 vehicles per day. The other station is surrounded by mixed residential and commercial buildings and 20 meters from a major road with over 20,000 vehicles per day. UFPs concentrations were monitored using six size channels: 20-30nm, 30-50nm, 50-70nm, 70-100nm, 100-200nm, and 200-450nm. The TSI 3031 monitors generally performed well for long-term UFP monitoring. Multi-year measurements of UFPs at the two stations show no apparent inter-annual variation or seasonality. Smaller particles (i.e., 20-50 nm) were found to be composed of over 50% of the measured particles. The observations are generally consistent with the theoretical understanding of particle nuclei mode and accumulation mode. When air mass originated from road traffic, UFPs were elevated in morning traffic hours and to a less extent in the late afternoon. The elevated UFPs number concentrations coincided with other traffic-related air pollutants like nitrogen oxides and black carbon. Moreover, higher number concentrations were found on weekdays than weekends. The observations suggest that UFPs are mostly from vehicle emissions.

  1. SEPARATION OF FISCHER-TROPSCH WAX PRODUCTS FROM ULTRAFINE IRON CATALYST PARTICLES

    SciTech Connect

    James K. Neathery; Gary Jacobs; Burtron H. Davis

    2004-09-30

    In this reporting period, a fundamental filtration study was continued to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. The overall focus of the program is with slurry-phase FTS in slurry bubble column reactor systems. Hydrocarbon products must be separated from catalyst particles before being removed from the reactor system. An efficient wax product/catalyst separation system is a key factor for optimizing operating costs for iron-based slurry-phase FTS. Previous work has focused on catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. With the current study, we are investigating how the filtration properties are affected by these chemical and physical changes of the catalyst slurry during activation/synthesis. The shakedown phase of the pilot-scale filtration platform was completed at the end of the last reporting period. A study of various molecular weight waxes was initiated to determine the effect of wax physical properties on the permeation rate without catalyst present. As expected, the permeation flux was inversely proportional to the nominal average molecular weight of the polyethylene wax. Even without catalyst particles present in the filtrate, the filtration membranes experience fouling during an induction period on the order of days on-line. Another long-term filtration test was initiated using a batch of iron catalyst that was previously activated with CO to form iron carbide in a separate continuous stirred tank reactor (CSTR) system. The permeation flux stabilized more rapidly than that experienced with unactivated catalyst tests.

  2. Ventilation dependence of concentration metrics of Ultra-fine Particles in a coagulating household smoke.

    PubMed

    Anand, S; Sreekanth, B; Mayya, Y S

    2016-01-01

    Role of Ultra-fine Particles (UFPs) in causing adverse health effects among large population across the world, attributable to household smoke, is being increasingly recognized. However, there is very little theoretical perspective available on the complex behavior of the UFP metrics with respect to controlling factors, such as ventilation rate and particle emission rate from the combustion sources. This numerical study examines through coagulation dynamics, the dependence of UFP metrics, viz., number (PN), mass (PM(0.1)) and surface area (PA(0.1)) concentrations below 0.1 μm diameter, on ventilation and the number emission rate from household smoke. For strong sources, the steady-state concentrations of these metrics are found to increase initially with increasing Air Exchange Rate (AER), reach a peak value and then decrease. Counter correlations are seen between UFP metric and PM(2.5) concentrations. The concepts of Critical Air Exchange Rate (CAER) and Half-Value Air Exchange Rate (HaVAER) have been introduced which indicate a feasibility of mitigation of PM(0.1) and PA(0.1), unlike PN, by ventilation techniques. The study clearly brings forth complex differential behavior of the three UFP metrics. The results are further discussed.

  3. [Adverse effects of ultrafine particles on the cardiovascular system and its mechanisms].

    PubMed

    Yi, Tie-ci; Li, Jian-ping

    2014-12-18

    Cardiovascular disease is one of the major threats to human. Air pollution, which , as it become a problem too serious to be ignored in China, is known to be an important risk factor for cardiovascular disease. Among all pollutants, ultrafine particles ( UFPs) , defined as particles with their diameter less than 0. 1 f.Lm, are a specific composition. They are very small in size, large in quantity and surface area, and most important, capable of passing through the air-blood barrier. These unique features of UFPs make them special in their impact on cardiovascular system. Nowadays, the influence of UFPs on the cardiovascular system has become a hot topic. On the one side, studies have shown that UFPs can cause inflammation and oxidative stress in the lung, and then induce systemic inflammation by releasing cytokine and reactive oxygen species into the circulation. On the other side, UFPs themselves can "spillout"into the circulation and interact with their targets. By this way, UFPs directly affect endothelial cells, myocardial cells and the autonomic nervous system, which ultimately result in increased cardiovascular events. We intend to make an overview about the recent progress about the influence of UFPs on human cardiovascular disease and the related mechanisms, and argue for more attention to this issue.

  4. Personal day-time exposure to ultrafine particles in different microenvironments.

    PubMed

    Gu, Jianwei; Kraus, Ute; Schneider, Alexandra; Hampel, Regina; Pitz, Mike; Breitner, Susanne; Wolf, Kathrin; Hänninen, Otto; Peters, Annette; Cyrys, Josef

    2015-03-01

    In order to assess the personal exposure to ultrafine particles (UFP) during individual day-time activities and to investigate the impact of different microenvironments on exposure, we measured personal exposure to particle number concentrations (PNC), a surrogate for UFP, among 112 non-smoking participants in Augsburg, Germany over a nearly two-year period from March 2007 to December 2008. We obtained 337 personal PNC measurements from 112 participants together with dairies of their activities and locations. The measurements lasted on average 5.5h and contained on average 330 observations. In addition, ambient PNC were measured at an urban background stationary monitoring site. Personal PNC were highly variable between measurements (IQR of mean: 11780-24650cm(-3)) and also within a single measurement. Outdoor personal PNC in traffic environments were about two times higher than in non-traffic environments. Higher indoor personal PNC were associated with activities like cooking, being in a bistro or exposure to passive smoking. Overall, personal and stationary PNC were weakly to moderately correlated (r<0.41). Personal PNC were much higher than stationary PNC in traffic (ratio: 1.5), when shopping (ratio: 2.4), and indoors with water vapor (ratio: 2.5). Additive mixed models were applied to predict personal PNC by participants' activities and locations. Traffic microenvironments were significant determinants for outdoor personal PNC. Being in a bistro, passive smoking, and cooking contributed significantly to an increased indoor personal PNC.

  5. Ultrafine particles from diesel engines induce vascular oxidative stress via JNK activation.

    PubMed

    Li, Rongsong; Ning, Zhi; Cui, Jeffery; Khalsa, Bhavraj; Ai, Lisong; Takabe, Wakako; Beebe, Tyler; Majumdar, Rohit; Sioutas, Constantinos; Hsiai, Tzung

    2009-03-15

    Exposure to particulate air pollution is linked to increased incidences of cardiovascular diseases. Ambient ultrafine particles (UFP) from diesel vehicle engines have been shown to be proatherogenic in ApoE knockout mice and may constitute a major cardiovascular risk in humans. We posited that circulating nano-sized particles from traffic pollution sources induce vascular oxidative stress via JNK activation in endothelial cells. Diesel UFP were collected from a 1998 Kenworth truck. Intracellular superoxide assay revealed that these UFP dose-dependently induced superoxide (O(2)(-)) production in human aortic endothelial cells (HAEC). Flow cytometry showed that UFP increased MitoSOX red intensity specific for mitochondrial superoxide. Protein carbonyl content was increased by UFP as an indication of vascular oxidative stress. UFP also up-regulated heme oxygenase-1 (HO-1) and tissue factor (TF) mRNA expression, and pretreatment with the antioxidant N-acetylcysteine significantly decreased their expression. Furthermore, UFP transiently activated JNK in HAEC. Treatment with the JNK inhibitor SP600125 and silencing of both JNK1 and JNK2 with siRNA inhibited UFP-stimulated O(2)(-) production and mRNA expression of HO-1 and TF. Our findings suggest that JNK activation plays an important role in UFP-induced oxidative stress and stress response gene expression.

  6. Total deposition of ultrafine particles in the lungs of healthy men and women: experimental and theoretical results

    PubMed Central

    2016-01-01

    Background Inhaled ultrafine particles (UFP) may induce greater adverse respiratory effects than larger particles occurring in the ambient atmosphere. Due to this potential of UFP to act as triggers for diverse lung injuries medical as well as physical research has been increasingly focused on the exact deposition behavior of the particles in lungs of various probands. Main purpose of the present study was the presentation of experimental and theoretical data of total, regional, and local UFP deposition in the lungs of men and women. Methods Both experiments and theoretical simulations were carried out by using particle sizes of 0.04, 0.06, 0.08, and 0.10 µm [number median diameters (NMD)]. Inhalation of UFP took place by application of predefined tidal volumes (500, 750, and 1,000 mL) and respiratory flow rates (150, 250, 375, and 500 mL·s−1). For male subjects a functional residual capacity (FRC) of 3,911±892 mL was measured, whereas female probands had a FRC of 3,314±547 mL. Theoretical predictions were based on (I) a stochastic model of the tracheobronchial tree; (II) particle transport computations according to a random walk algorithm; and (III) empirical formulae for the description of UFP deposition. Results Total deposition fractions (TDF) are marked by a continuous diminution with increasing particle size. Whilst particles measuring 0.04 µm in size deposit in the respiratory tract by 40–70%, particles with a size of 0.10 µm exhibit deposition values ranging from 20% to 45%. Except for the largest particles studied here TDF of female probands are higher than those obtained for male probands. Differences between experimental and theoretical results are most significant for 0.10 µm particles, but never exceed 20%. Predictions of regional (extrathoracic, tracheobronchial, alveolar) UFP deposition show clearly that females tend to develop higher tracheobronchial and alveolar deposition fractions than males. This discrepancy is also confirmed by

  7. Characterization of ultrafine particle number concentration and new particle formation in an urban environment of Taipei, Taiwan

    NASA Astrophysics Data System (ADS)

    Cheung, H. C.; Chou, C. C.-K.; Huang, W.-R.; Tsai, C.-Y.

    2013-09-01

    An intensive aerosol characterization experiment was performed at the Taipei Aerosol and Radiation Observatory (TARO, 25.02° N, 121.53° E) in the urban area of Taipei, Taiwan, during July 2012. Number concentration and size distribution of aerosol particles were measured continuously, which were accompanied by concurrent measurements of mass concentration of submicron particles, PM1 (d ≤ 1 μm), and photolysis rate of ozone, J(O1D). The averaged number concentrations of total (Ntotal), accumulation mode (Nacu), Aitken mode (NAitken), and nucleation mode (Nnuc) particles were 13.9 × 103 cm-3, 1.2 × 103 cm-3, 6.1 × 103 cm-3, and 6.6 × 103 cm-3, respectively. Accordingly, the ultrafine particles (UFPs, d ≤ 100 nm) accounted for 91% of the total number concentration of particles measured in this study (10 ≤ d ≤ 429 nm), indicating the importance of UFPs to the air quality and radiation budget in Taipei and its surrounding areas. An averaged Nnuc / NOx ratio of 192.4 cm-3 ppbv-1 was derived from nighttime measurements, which was suggested to be the characteristic of vehicle emissions that contributed to the "urban background" of nucleation mode particles throughout a day. On the contrary, it was found that the number concentration of nucleation mode particles was independent of NOx and could be elevated up to 10 times of the "urban background" levels during daytime, suggesting a substantial amount of nucleation mode particles produced from photochemical processes. Averages (± 1σ) of the diameter growth rate (GR) and formation rate of nucleation mode particles, J10, were 11.9 ± 10.6 nm h-1 and 6.9 ± 3.0 cm-3 s-1, respectively. Consistency in the time series of the nucleation mode particle concentration and the proxy of H2SO4 production, UVB · SO2/CS, for new particle formation (NPF) events suggested that photooxidation of SO2 was likely one of the major mechanisms for the formation of new particles in our study area. Moreover, it was revealed that the

  8. Redox activity of urban quasi-ultrafine particles from primary and secondary sources

    NASA Astrophysics Data System (ADS)

    Verma, Vishal; Ning, Zhi; Cho, Arthur K.; Schauer, James J.; Shafer, Martin M.; Sioutas, Constantinos

    2009-12-01

    To characterize the redox activity profiles of atmospheric aerosols from primary (traffic) and secondary photochemical sources, ambient quasi-ultrafine particles were collected near downtown Los Angeles in two different time periods - morning (6:00-9:00 PDT) and afternoon (11:00-14:00 PDT) in the summer of 2008. Detailed chemical analysis of the collected samples, including water-soluble elements, inorganic ions, organic species and water soluble organic carbon (WSOC) was conducted and redox activity of the samples was measured by two different assays: the dithiothreitol (DTT) and the macrophage reactive oxygen species (ROS) assays. Tracers of secondary photochemical reactions, such as sulfate and organic acids were higher (2.1 ± 0.6 times for sulfate, and up to 3 times for the organic acids) in the afternoon period. WSOC was also elevated by 2.5 ± 0.9 times in the afternoon period due to photo-oxidation of primary particles during atmospheric aging. Redox activity measured by the DTT assay was considerably higher for the samples collected during the afternoon; on the other hand, diurnal trends in the ROS-based activity were not consistent between the morning and afternoon periods. A linear regression between redox activity and various PM chemical constituents showed that the DTT assay was highly correlated with WSOC ( R2 = 0.80), while ROS activity was associated mostly with water soluble transition metals (Vanadium, Nickel and Cadmium; R2 > 0.70). The DTT and ROS assays, which are based on the generation of different oxidizing species by chemical PM constituents, provide important information for elucidating the health risks related to PM exposure from different sources. Thus, both primary and secondary particles possess high redox activity; however, photochemical transformations of primary emissions with atmospheric aging enhance the toxicological potency of primary particles in terms of generating oxidative stress and leading to subsequent damage in cells.

  9. Measurements of ultrafine particles and other vehicular pollutants inside school buses in South Texas

    NASA Astrophysics Data System (ADS)

    Zhang, Qunfang; Zhu, Yifang

    2010-01-01

    Increasing evidence has demonstrated toxic effects of vehicular emitted ultrafine particles (UFPs, diameter < 100 nm), with the highest human exposure usually occurring on and near roadways. Children are particularly at risk due to immature respiratory systems and faster breathing rates. In this study, children's exposure to in-cabin air pollutants, especially UFPs, was measured inside four diesel-powered school buses. Two 1990 and two 2006 model year diesel-powered school buses were selected to represent the age extremes of school buses in service. Each bus was driven on two routine bus runs to study school children's exposure under different transportation conditions in South Texas. The number concentration and size distribution of UFPs, total particle number concentration, PM 2.5, PM 10, black carbon (BC), CO, and CO 2 levels were monitored inside the buses. The average total particle number concentrations observed inside the school buses ranged from 7.3 × 10 3 to 3.4 × 10 4 particles cm -3, depending on engine age and window position. When the windows were closed, the in-cabin air pollutants were more likely due to the school buses' self-pollution. The 1990 model year school buses demonstrated much higher air pollutant concentrations than the 2006 model year ones. When the windows were open, the majority of in-cabin air pollutants came from the outside roadway environment with similar pollutant levels observed regardless of engine ages. The highest average UFP concentration was observed at a bus transfer station where approximately 27 idling school buses were queued to load or unload students. Starting-up and idling generated higher air pollutant levels than the driving state. Higher in-cabin air pollutant concentrations were observed when more students were on board.

  10. SEPARATION OF FISCHER-TROPSCH WAX PRODUCTS FROM ULTRAFINE IRON CATALYST PARTICLES

    SciTech Connect

    James K. Neathery; Gary Jacobs; Burtron H. Davis

    2005-03-31

    In this reporting period, a fundamental filtration study was continued to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. The overall focus of the program is with slurry-phase FTS in slurry bubble column reactor systems. Hydrocarbon products must be separated from catalyst particles before being removed from the reactor system. An efficient wax product/catalyst separation system is a key factor for optimizing operating costs for iron-based slurry-phase FTS. Previous work has focused on catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. With the current study, we are investigating how the filtration properties are affected by these chemical and physical changes of the catalyst slurry during activation/synthesis. In this reporting period, a series of crossflow filtration experiments were initiated to study the effect of olefins and oxygenates on the filtration flux and membrane performance. Iron-based FTS reactor waxes contain a significant amount of oxygenates, depending on the catalyst formulation and operating conditions. Mono-olefins and aliphatic alcohols were doped into an activated iron catalyst slurry (with Polywax) to test their influence on filtration properties. The olefins were varied from 5 to 25 wt% and oxygenates from 6 to 17 wt% to simulate a range of reactor slurries reported in the literature. The addition of an alcohol (1-dodecanol) was found to decrease the permeation rate while the olefin added (1-hexadecene) had no effect on the permeation rate. A passive flux maintenance technique was tested that can temporarily increase the permeate rate for 24 hours.

  11. Quinones and Aromatic Chemical Compounds in Particulate Matter Induce Mitochondrial Dysfunction: Implications for Ultrafine Particle Toxicity

    PubMed Central

    Xia, Tian; Korge, Paavo; Weiss, James N.; Li, Ning; Venkatesen, M. Indira; Sioutas, Constantinos; Nel, Andre

    2004-01-01

    Particulate pollutants cause adverse health effects through the generation of oxidative stress. A key question is whether these effects are mediated by the particles or their chemical compounds. In this article we show that aliphatic, aromatic, and polar organic compounds, fractionated from diesel exhaust particles (DEPs), exert differential toxic effects in RAW 264.7 cells. Cellular analyses showed that the quinone-enriched polar fraction was more potent than the polycyclic aromatic hydrocarbon (PAH)–enriched aromatic fraction in O2•− generation, decrease of membrane potential (ΔΨm), loss of mitochondrial membrane mass, and induction of apoptosis. A major effect of the polar fraction was to promote cyclosporin A (CsA)–sensitive permeability transition pore (PTP) opening in isolated liver mitochondria. This opening effect is dependent on a direct effect on the PTP at low doses as well as on an effect on ΔΨm at high doses in calcium (Ca2+)-loaded mitochondria. The direct PTP effect was mimicked by redox-cycling DEP quinones. Although the aliphatic fraction failed to perturb mitochondrial function, the aromatic fraction increased the Ca2+ retention capacity at low doses and induced mitochondrial swelling and a decrease in ΔΨm at high doses. This swelling effect was mostly CsA insensitive and could be reproduced by a mixture of PAHs present in DEPs. These chemical effects on isolated mitochondria could be reproduced by intact DEPs as well as ambient ultrafine particles (UFPs). In contrast, commercial polystyrene nanoparticles failed to exert mitochondrial effects. These results suggest that DEP and UFP effects on the PTP and ΔΨm are mediated by adsorbed chemicals rather than the particles themselves. PMID:15471724

  12. The formation and growth of ultrafine particles in two contrasting environments: a case study

    NASA Astrophysics Data System (ADS)

    Kompalli, Sobhan Kumar; Babu, S. Suresh; Krishna Moorthy, K.; Gogoi, Mukunda M.; Nair, Vijayakumar S.; Chaubey, Jai Prakash

    2014-07-01

    Formation of ultrafine particles and their subsequent growth have been examined during new particle formation (NPF) events in two contrasting environments under varying ambient conditions, one for a tropical semi-urban coastal station, Trivandrum, and the other for a high-altitude free-tropospheric Himalayan location, Hanle. At Trivandrum, NPF bursts took place in the late evening/night hours, whereas at Hanle the burst was a daytime event. During the nucleation period, the total number concentration reached levels as high as ~ 15 900 cm-3 at Trivandrum, whereas at Hanle, the total number concentration was ~ 2700 cm-3, indicating the abundant availability of precursors at Trivandrum and the pristine nature of Hanle. A sharp decrease was associated with NPF for the geometric mean diameter of the size distribution, and a large increase in the concentration of the particles in the nucleation regime (Dp < 25 nm). Once formed, these (secondary) aerosols grew from nucleation (diameter Dp < 25 nm) to Aitken (25 ≤ Dp ≤ 100 nm) regime and beyond, to the accumulation size regimes (100 ≤ Dp ≤ 1000 nm), with varying growth rates (GR) for the different size regimes at both the locations. A more rapid growth ~ 50 nm h-1 was observed at Trivandrum, in contrast to Hanle where the growth rate ranged from 0.1 to 20 nm h-1 for the transformation from the nucleation to accumulation - a size regime that can potentially act as cloud condensation nuclei (CCN). The faster coagulation led to lifetimes of < 1 h for nucleation mode particles.

  13. Inhalation of ultrafine particles alters blood leukocyte expression of adhesion molecules in humans.

    PubMed

    Frampton, Mark W; Stewart, Judith C; Oberdörster, Günter; Morrow, Paul E; Chalupa, David; Pietropaoli, Anthony P; Frasier, Lauren M; Speers, Donna M; Cox, Christopher; Huang, Li-Shan; Utell, Mark J

    2006-01-01

    Ultrafine particles (UFPs; aerodynamic diameter < 100 nm) may contribute to the respiratory and cardiovascular morbidity and mortality associated with particulate air pollution. We tested the hypothesis that inhalation of carbon UFPs has vascular effects in healthy and asthmatic subjects, detectable as alterations in blood leukocyte expression of adhesion molecules. Healthy subjects inhaled filtered air and freshly generated elemental carbon particles (count median diameter approximately 25nm, geometric standard deviation approximately 1.6), for 2 hr, in three separate protocols: 10 microg/m3 at rest, 10 and 25 microg/m3 with exercise, and 50 microg/m3 with exercise. In a fourth protocol, subjects with asthma inhaled air and 10 microg/m3 UFPs with exercise. Peripheral venous blood was obtained before and at intervals after exposure, and leukocyte expression of surface markers was quantitated using multiparameter flow cytometry. In healthy subjects, particle exposure with exercise reduced expression of adhesion molecules CD54 and CD18 on monocytes and CD18 and CD49d on granulocytes. There were also concentration-related reductions in blood monocytes, basophils, and eosinophils and increased lymphocyte expression of the activation marker CD25. In subjects with asthma, exposure with exercise to 10 microg/m3 UFPs reduced expression of CD11b on monocytes and eosinophils and CD54 on granulocytes. Particle exposure also reduced the percentage of CD4+ T cells, basophils, and eosinophils. Inhalation of elemental carbon UFPs alters peripheral blood leukocyte distribution and expression of adhesion molecules, in a pattern consistent with increased retention of leukocytes in the pulmonary vascular bed.

  14. Concentrations of fine, ultrafine, and black carbon particles in auto-rickshaws in New Delhi, India

    NASA Astrophysics Data System (ADS)

    Apte, Joshua, S.; Kirchstetter, Thomas W.; Reich, Alexander, H.; Deshpande, Shyam J.; Kaushik, Geetanjali; Chel, Arvind; Marshall, Julian D.; Nazaroff, William W.

    2011-08-01

    Concentrations of air pollutants from vehicles are elevated along roadways, indicating that human exposure in transportation microenvironments may not be adequately characterized by centrally located monitors. We report results from ˜180 h of real-time measurements of fine particle and black carbon mass concentration (PM 2.5, BC) and ultrafine particle number concentration (PN) inside a common vehicle, the auto-rickshaw, in New Delhi, India. Measured exposure concentrations are much higher in this study (geometric mean for ˜60 trip-averaged concentrations: 190 μg m -3 PM 2.5, 42 μg m -3 BC, 280 × 10 3 particles cm -3; GSD ˜1.3 for all three pollutants) than reported for transportation microenvironments in other megacities. In-vehicle concentrations exceeded simultaneously measured ambient levels by 1.5× for PM 2.5, 3.6× for BC, and 8.4× for PN. Short-duration peak concentrations (averaging time: 10 s), attributable to exhaust plumes of nearby vehicles, were greater than 300 μg m -3 for PM 2.5, 85 μg m -3 for BC, and 650 × 10 3 particles cm -3 for PN. The incremental increase of within-vehicle concentration above ambient levels—which we attribute to in- and near-roadway emission sources—accounted for 30%, 68% and 86% of time-averaged in-vehicle PM 2.5, BC and PN concentrations, respectively. Based on these results, we estimate that one's exposure during a daily commute by auto-rickshaw in Delhi is as least as large as full-day exposures experienced by urban residents of many high-income countries. This study illuminates an environmental health concern that may be common in many populous, low-income cities.

  15. ALADINA - an unmanned research aircraft for observing vertical and horizontal distributions of ultrafine particles within the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Altstädter, B.; Platis, A.; Wehner, B.; Scholtz, A.; Wildmann, N.; Hermann, M.; Käthner, R.; Baars, H.; Bange, J.; Lampert, A.

    2015-04-01

    This paper presents the unmanned research aircraft Carolo P360 "ALADINA" (Application of Light-weight Aircraft for Detecting IN situ Aerosol) for investigating the horizontal and vertical distribution of ultrafine particles in the atmospheric boundary layer (ABL). It has a wingspan of 3.6 m, a maximum take-off weight of 25 kg and is equipped with aerosol instrumentation and meteorological sensors. A first application of the system, together with the unmanned research aircraft MASC (Multi-Purpose Airborne Carrier) of the Eberhard Karls University of Tübingen (EKUT), is described. As small payload for ALADINA, two condensation particle counters (CPC) and one optical particle counter (OPC) were miniaturised by re-arranging the vital parts and composing them in a space-saving way in the front compartment of the airframe. The CPCs are improved concerning the lower detection threshold and the response time to less than 1.3 s. Each system was characterised in the laboratory and calibrated with test aerosols. The CPCs are operated in this study with two different lower detection threshold diameters of 11 and 18 nm. The amount of ultrafine particles, which is an indicator for new particle formation, is derived from the difference in number concentrations of the two CPCs (ΔN). Turbulence and thermodynamic structure of the boundary layer are described by measurements of fast meteorological sensors that are mounted at the aircraft nose. A first demonstration of ALADINA and a feasibility study were conducted in Melpitz near Leipzig, Germany, at the Global Atmosphere Watch (GAW) station of the Leibniz Institute for Tropospheric Research (TROPOS) on 2 days in October 2013. There, various ground-based instruments are installed for long-term atmospheric monitoring. The ground-based infrastructure provides valuable additional background information to embed the flights in the continuous atmospheric context and is used for validation of the airborne results. The development of the

  16. Measurements of fine and ultrafine particles formation in photocopy centers in Taiwan

    NASA Astrophysics Data System (ADS)

    Lee, Chia-Wei; Hsu, Der-Jen

    This study investigates the levels of particulate matter smaller than 2.5 μm (PM 2.5) and some selected volatile organic compounds (VOCs) at 12 photocopy centers in Taiwan from November 2004 to June 2005. The results of BTEXS (benzene, toluene, ethylbenzene, xylenes and styrene) measurements indicated that toluene had the highest concentration in all photocopy centers, while the concentration of the other four compounds varied among the 12 photocopy centers. The average background-corrected eight-hour PM 2.5 in the 12 photocopy centers ranged from 10 to 83 μg m -3 with an average of 40 μg m -3. The 24-h indoor PM 2.5 at the photocopy centers was estimated and at two photocopy centers exceeded 100 μg m -3, the 24-h indoor PM 2.5 guideline recommended by the Taiwan EPA. The ozone level and particle size distribution at another photocopy center were monitored and indicated that the ozone level increased when the photocopying started and the average ozone level at some photocopy centers during business hour may exceed the value (50 ppb) recommended by the Taiwan EPA. The particle size distribution monitored during photocopying indicated that the emitted particles were much smaller than the original toner powders. Additionally, the number concentration of particles that were smaller than 0.5 μm was found to increase during the first hour of photocopying and it increased as the particle size decreased. The ultrafine particle (UFP, <100 nm) dominated the number concentration and the peak concentration appeared at sizes of under 50 nm. A high number concentration of UFP was found with a peak value of 1E+8 particles cm -3 during photocopying. The decline of UFP concentration was observed after the first hour and the decline is likely attributable to the surface deposition of charged particles, which are charged primarily by the diffusion charging of corona devices in the photocopier. This study concludes that ozone and UFP concentrations in photocopy centers should be

  17. Land Use Regression Models for Ultrafine Particles and Black Carbon Based on Short-Term Monitoring Predict Past Spatial Variation.

    PubMed

    Montagne, Denise R; Hoek, Gerard; Klompmaker, Jochem O; Wang, Meng; Meliefste, Kees; Brunekreef, Bert

    2015-07-21

    Health effects of long-term exposure to ultrafine particles (UFP) have not been investigated in epidemiological studies because of the lack of spatially resolved UFP exposure data. Short-term monitoring campaigns used to develop land use regression (LUR) models for UFP typically had moderate performance. The aim of this study was to develop and evaluate spatial and spatiotemporal LUR models for UFP and Black Carbon (BC), including their ability to predict past spatial contrasts. We measured 30 min at each of 81 sites in Amsterdam and 80 in Rotterdam, The Netherlands in three different seasons. Models were developed using traffic, land use, reference site measurements, routinely measured pollutants and weather data. The percentage explained variation (R(2)) was 0.35-0.40 for BC and 0.33-0.42 for UFP spatial models. Traffic variables were present in every model. The coefficients for the spatial predictors were similar in spatial and spatiotemporal models. The BC LUR model explained 61% of the spatial variation in a previous campaign with longer sampling duration, better than the model R(2). The UFP LUR model explained 36% of UFP spatial variation measured 10 years earlier, similar to the model R(2). Short-term monitoring campaigns may be an efficient tool to develop LUR models.

  18. ALADINA - an unmanned research aircraft for observing vertical and horizontal distributions of ultrafine particles within the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Altstädter, B.; Platis, A.; Wehner, B.; Scholtz, A.; Lampert, A.; Wildmann, N.; Hermann, M.; Käthner, R.; Bange, J.; Baars, H.

    2014-12-01

    This paper presents the unmanned research aircraft Carolo P360 "ALADINA" (Application of Light-weight Aircraft for Detecting IN-situ Aerosol) for investigating the horizontal and vertical distribution of ultrafine particles in the atmospheric boundary layer (ABL). It has a wingspan of 3.6 m, a maximum take-off weight of 25 kg and is equipped with aerosol instrumentation and meteorological sensors. A first application of the system, together with the unmanned research aircraft MASC (Multi-Purpose Airborne Carrier) of the Eberhard-Karls University of Tübingen (EKUT), is described. As small payload for ALADINA, two condensation particle counters (CPC) and one optical particle counter (OPC) were miniaturized by re-arranging the vital parts and composing them in a space saving way in the front compartment of the airframe. The CPCs are improved concerning the lower detection threshold and the response time. Each system was characterized in the laboratory and calibrated with test aerosols. The CPCs are operated with two different lower detection threshold diameters of 6 and 18 nm. The amount of ultrafine particles, which is an indicator for new particle formation, is derived from the difference in number concentrations of the two CPCs. Turbulence and thermodynamic structure of the boundary layer are described by measurements of fast meteorological sensors that are mounted at the aircraft nose. A first demonstration of ALADINA and a feasibility study were conducted in Melpitz near Leipzig, Germany, at the Global Atmosphere Watch (GAW) station of the Leibniz Institute for Tropospheric Research (TROPOS) on two days in October 2013. There, various ground-based instruments are installed for long-term atmospheric monitoring. The ground-based infrastructure provides valuable additional background information to embed the flights in the continuous atmospheric context and is used for validation of the airborne results. The development of the boundary layer, derived from

  19. Air pollutant concentrations near three Texas roadways, Part I: Ultrafine particles

    NASA Astrophysics Data System (ADS)

    Zhu, Yifang; Pudota, Jayanth; Collins, Donald; Allen, David; Clements, Andrea; DenBleyker, Allison; Fraser, Matt; Jia, Yuling; McDonald-Buller, Elena; Michel, Edward

    Vehicular emitted air pollutant concentrations were studied near three types of roadways in Austin, Texas: (1) State Highway 71 (SH-71), a heavily traveled arterial highway dominated by passenger vehicles; (2) Interstate 35 (I-35), a limited access highway north of Austin in Georgetown; and (3) Farm to Market Road 973 (FM-973), a heavily traveled surface roadway dominated by truck traffic. Air pollutants examined include carbon monoxide (CO), oxides of nitrogen (NO x), and carbonyl species in the gas-phase. In the particle phase, ultrafine particle (UFP) concentrations (diameter < 100 nm), fine particulate matter (PM 2.5, diameter < 2.5 μm) mass and carbon content and several particle-bound organics were examined. All roadways had an upwind stationary sampling location, one or two fixed downwind sample locations and a mobile monitoring platform that characterized pollutant concentrations fall-off with increased distance from the roadways. Data reported in this paper focus on UFP while other pollutants and near-roadway chemical processes are examined in a companion paper. Traffic volume, especially heavy-duty traffic, wind speed, and proximity to the road were found to be the most important factors determining UFP concentrations near the roadways. Since wind directions were not consistent during the sampling periods, distances along wind trajectories from the roadway to the sampling points were used to study the decay characteristics of UFPs. Under perpendicular wind conditions, for all studied roadway types, particle number concentrations increased dramatically moving from the upwind side to the downwind side. The elevated particle number concentrations decay exponentially with increasing distances from the roadway with sharp concentration gradients observed within 100-150 m, similar to previously reported studies. A single exponential decay curve was found to fit the data collected from all three roadways very well under perpendicular wind conditions. No

  20. Characterization of decay and emission rates of ultrafine particles in indoor ice rink.

    PubMed

    Kim, J; Lee, K

    2013-08-01

    The purposes of this study were to determine indoor ultrafine particle (UFP, diameter <100 nm) levels in ice rinks and to characterize UFP decay and emission rates. All 15 public ice rinks in Seoul were investigated for UFP and carbon monoxide (CO) concentrations. Three ice rinks did not show peaks in UFP concentrations, and one ice rink used two resurfacers simultaneously. High peaks of UFP and CO concentrations were observed when the resurfacer was operated. The average air change rate in the 11 ice rinks was 0.21 ± 0.13/h. The average decay rates of UFP number concentrations measured by the P-Trak and DiSCmini were 0.54 ± 0.21/h and 0.85 ± 0.34/h, respectively. The average decay rate of UFP surface area concentration was 0.33 ± 0.15/h. The average emission rates of UFP number concentrations measured by P-Trak and DiSCmini were 1.2 × 10(14) ± 6.5 × 10(13) particles/min and 3.3 × 10(14) ± 2.4 × 10(14) particles/min, respectively. The average emission rate of UFP surface area concentration was 3.1 × 10(11) ± 2.0 × 10(11) μm(2)/min. UFP emission rate was associated with resurfacer age. DiSCmini measured higher decay and emission rates than P-Trak due to their different measuring mechanisms and size ranges.

  1. Effect of particle-fiber friction coefficient on ultrafine aerosol particles clogging in nanofiber based filter

    NASA Astrophysics Data System (ADS)

    Sambaer, Wannes; Zatloukal, Martin; Kimmer, Dusan

    2013-04-01

    Realistic SEM image based 3D filter model considering transition/free molecular flow regime, Brownian diffusion, aerodynamic slip, particle-fiber and particle-particle interactions together with a novel Euclidian distance map based methodology for the pressure drop calculation has been utilized for a polyurethane nanofiber based filter prepared via electrospinning process in order to more deeply understand the effect of particle-fiber friction coefficient on filter clogging and basic filter characteristics. Based on the performed theoretical analysis, it has been revealed that the increase in the fiber-particle friction coefficient causes, firstly, more weaker particle penetration in the filter, creation of dense top layers and generation of higher pressure drop (surface filtration) in comparison with lower particle-fiber friction coefficient filter for which deeper particle penetration takes place (depth filtration), secondly, higher filtration efficiency, thirdly, higher quality factor and finally, higher quality factor sensitivity to the increased collected particle mass. Moreover, it has been revealed that even if the particle-fiber friction coefficient is different, the cake morphology is very similar.

  2. Breathing resistance and ultrafine particle deposition in nasal-laryngeal airways of a newborn, an infant, a child, and an adult.

    PubMed

    Xi, Jinxiang; Berlinski, Ariel; Zhou, Yue; Greenberg, Bruce; Ou, Xiawei

    2012-12-01

    As a human grows from birth to adulthood, both airway anatomy and breathing conditions vary, altering the deposition rate and pattern of inhaled aerosols. However, deposition studies have typically focused on adult subjects, results of which may not be readily extrapolated to children. This study numerically evaluated the age-related effects on the airflow and aerosol dynamics in image-based nose-throat models of a 10-day-old newborn, a 7-month-old infant, a 5-year-old child, and a 53-year-old adult. Differences in airway physiology, breathing resistance, and aerosol filtering efficiency among the four models were quantified and compared. A high-fidelity fluid-particle transport model was employed to simulate the multi-regime airflows and particle transport within the nasal-laryngeal airways. Ultrafine particles were evaluated under breathing conditions ranging from sedentary to heavy activities. Results of this study indicate that the nasal-laryngeal airways at different ages, albeit differ significantly in morphology and dimension, do not significantly affect the total deposition fractions or maximum local deposition enhancement for ultrafine aerosols. Further, the deposition partitioning in the sub-regions of interest is different among the four models. Results of this study corroborate the use of the in vivo-based diffusion parameter (D(0.5)Q(-0.28)) over the replica-based parameter in correlating nasal-laryngeal depositions of ultrafine aerosols. Improved correlations have been developed for the four age groups by implementing this in vivo-based diffusion parameter as well as the Cunningham correction factor.

  3. Modeling ultrafine particle growth at a pine forest site influenced by anthropogenic pollution during BEACHON-RoMBAS 2011

    NASA Astrophysics Data System (ADS)

    Cui, Y. Y.; Hodzic, A.; Smith, J. N.; Ortega, J.; Brioude, J.; Matsui, H.; Levin, E. J. T.; Turnipseed, A.; Winkler, P.; de Foy, B.

    2014-10-01

    Formation and growth of ultrafine particles is crudely represented in chemistry-climate models, contributing to uncertainties in aerosol composition, size distribution, and aerosol effects on cloud condensation nuclei (CCN) concentrations. Measurements of ultrafine particles, their precursor gases, and meteorological parameters were performed in a ponderosa pine forest in the Colorado Front Range in July-August 2011, and were analyzed to study processes leading to small particle burst events (PBEs) which were characterized by an increase in the number concentrations of ultrafine 4-30 nm diameter size particles. These measurements suggest that PBEs were associated with the arrival at the site of anthropogenic pollution plumes midday to early afternoon. During PBEs, number concentrations of 4-30 nm diameter particles typically exceeded 104 cm-3, and these elevated concentrations coincided with increased SO2 and monoterpene concentrations, and led to a factor-of-2 increase in CCN concentrations at 0.5% supersaturation. The PBEs were simulated using the regional WRF-Chem model, which was extended to account for ultrafine particle sizes starting at 1 nm in diameter, to include an empirical activation nucleation scheme in the planetary boundary layer, and to explicitly simulate the subsequent growth of Aitken particles (10-100 nm) by condensation of organic and inorganic vapors. The updated model reasonably captured measured aerosol number concentrations and size distribution during PBEs, as well as ground-level CCN concentrations. Model results suggest that sulfuric acid originating from anthropogenic SO2 triggered PBEs, and that the condensation of monoterpene oxidation products onto freshly nucleated particles contributes to their growth. The simulated growth rate of ~ 3.4 nm h-1 for 4-40 nm diameter particles was comparable to the measured average value of 2.3 nm h-1. Results also suggest that the presence of PBEs tends to modify the composition of sub-20 nm diameter

  4. Exposure to ultrafine particles and black carbon in diesel-powered commuter trains

    NASA Astrophysics Data System (ADS)

    Jeong, Cheol-Heon; Traub, Alison; Evans, Greg J.

    2017-04-01

    Ultrafine particle (UFP), black carbon (BC) and lung deposited surface area (LDSA) concentrations measured during 43 trips on diesel-powered commuter trains revealed elevated exposures under some conditions. When the passenger coaches were pulled by a locomotive, the geometric mean concentrations of UFP, LDSA, and BC were 18, 10, and 6 times higher than the exposure levels when the locomotive pushed the coaches, respectively. In addition, UFP, LDSA, and BC concentrations in pull-trains were 5, 3, and 4 times higher than concentrations measured while walking on city sidewalks, respectively. Exposure to these pollutants was most elevated in the coach located closest to the locomotive: geometric means were 126,000 # cm-3 for UFP, 249 μm2 cm-3 for LDSA, and 17,800 ng m-3 of BC; these concentrations are much higher than those previously reported for other modes of public transportation. Markedly high levels of diesel exhaust are present in passenger trains powered by diesel locomotives operated in pull-mode. Thus, it is recommended that immediate steps be taken to evaluate, and where needed, mitigate exposure in diesel-powered passenger trains, both commuter and inter-city.

  5. Effect of cabin ventilation rate on ultrafine particle exposure inside automobiles.

    PubMed

    Knibbs, Luke D; de Dear, Richard J; Morawska, Lidia

    2010-05-01

    We alternately measured on-road and in-vehicle ultrafine (<100 nm) particle (UFP) concentration for 5 passenger vehicles that comprised an age range of 18 years. A range of cabin ventilation settings were assessed during 301 trips through a 4 km road tunnel in Sydney, Australia. Outdoor air flow (ventilation) rates under these settings were quantified on open roads using tracer gas techniques. Significant variability in tunnel trip average median in-cabin/on-road (I/O) UFP ratios was observed (0.08 to approximately 1.0). Based on data spanning all test automobiles and ventilation settings, a positive linear relationship was found between outdoor air flow rate and I/O ratio, with the former accounting for a substantial proportion of variation in the latter (R(2) = 0.81). UFP concentrations recorded in-cabin during tunnel travel were significantly higher than those reported by comparable studies performed on open roadways. A simple mathematical model afforded the ability to predict tunnel trip average in-cabin UFP concentrations with good accuracy. Our data indicate that under certain conditions, in-cabin UFP exposures incurred during tunnel travel may contribute significantly to daily exposure. The UFP exposure of automobile occupants appears strongly related to their choice of ventilation setting and vehicle.

  6. Morphology of Nano and Micro Fiber Structures in Ultrafine Particles Filtration

    SciTech Connect

    Kimmer, Dusan; Vincent, Ivo; Fenyk, Jan; Petras, David; Zatloukal, Martin; Sambaer, Wannes; Zdimal, Vladimir

    2011-07-15

    Selected procedures permitting to prepare homogeneous nanofibre structures of the desired morphology by employing a suitable combination of variables during the electrospinning process are presented. A comparison (at the same pressure drop) was made of filtration capabilities of planar polyurethane nanostructures formed exclusively by nanofibres, space polycarbonate nanostructures having bead spacers, structures formed by a combination of polymethyl methacrylate micro- and nanofibres and polypropylene meltblown microstructures, through which ultrafine particles of ammonium sulphate 20-400 nm in size were filtered. The structures studied were described using a new digital image analysis technique based on black and white images obtained by scanning electron microscopy. More voluminous structures modified with distance microspheres and having a greater thickness and mass per square area of the material, i.e. structures possessing better mechanical properties, demanded so much in nanostructures, enable preparation of filters having approximately the same free volume fraction as flat nanofibre filters but an increased effective fibre surface area, changed pore size morphology and, consequently, a higher filter quality.

  7. An hourly regression model for ultrafine particles in a near-highway urban area

    PubMed Central

    Patton, Allison P.; Collins, Caitlin; Naumova, Elena N.; Zamore, Wig; Brugge, Doug; Durant, John L.

    2015-01-01

    Estimating ultrafine particle number concentrations (PNC) near highways for exposure assessment in chronic health studies requires models capable of capturing PNC spatial and temporal variations over the course of a full year. The objectives of this work were to describe the relationship between near-highway PNC and potential predictors, and to build and validate hourly log-linear regression models. PNC was measured near Interstate 93 (I-93) in Somerville, MA (USA) using a mobile monitoring platform driven for 234 hours on 43 days between August 2009 and September 2010. Compared to urban background, PNC levels were consistently elevated within 100–200 m of I-93, with gradients impacted by meteorological and traffic conditions. Temporal and spatial variables including wind speed and direction, temperature, highway traffic, and distance to I-93 and major roads contributed significantly to the full regression model. Cross-validated model R2 values ranged from 0.38–0.47, with higher values achieved (0.43–0.53) when short-duration PNC spikes were removed. The model predicts highest PNC near major roads and on cold days with low wind speeds. The model allows estimation of hourly ambient PNC at 20-m resolution in a near-highway neighborhood. PMID:24559198

  8. Morphology of Nano and Micro Fiber Structures in Ultrafine Particles Filtration

    NASA Astrophysics Data System (ADS)

    Kimmer, Dusan; Vincent, Ivo; Fenyk, Jan; Petras, David; Zatloukal, Martin; Sambaer, Wannes; Zdimal, Vladimir

    2011-07-01

    Selected procedures permitting to prepare homogeneous nanofibre structures of the desired morphology by employing a suitable combination of variables during the electrospinning process are presented. A comparison (at the same pressure drop) was made of filtration capabilities of planar polyurethane nanostructures formed exclusively by nanofibres, space polycarbonate nanostructures having bead spacers, structures formed by a combination of polymethyl methacrylate micro- and nanofibres and polypropylene meltblown microstructures, through which ultrafine particles of ammonium sulphate 20-400 nm in size were filtered. The structures studied were described using a new digital image analysis technique based on black and white images obtained by scanning electron microscopy. More voluminous structures modified with distance microspheres and having a greater thickness and mass per square area of the material, i.e. structures possessing better mechanical properties, demanded so much in nanostructures, enable preparation of filters having approximately the same free volume fraction as flat nanofibre filters but an increased effective fibre surface area, changed pore size morphology and, consequently, a higher filter quality.

  9. Autophagy is essential for ultrafine particle-induced inflammation and mucus hyperproduction in airway epithelium.

    PubMed

    Chen, Zhi-Hua; Wu, Yin-Fang; Wang, Ping-Li; Wu, Yan-Ping; Li, Zhou-Yang; Zhao, Yun; Zhou, Jie-Sen; Zhu, Chen; Cao, Chao; Mao, Yuan-Yuan; Xu, Feng; Wang, Bei-Bei; Cormier, Stephania A; Ying, Song-Min; Li, Wen; Shen, Hua-Hao

    2016-01-01

    Environmental ultrafine particulate matter (PM) is capable of inducing airway injury, while the detailed molecular mechanisms remain largely unclear. Here, we demonstrate pivotal roles of autophagy in regulation of inflammation and mucus hyperproduction induced by PM containing environmentally persistent free radicals in human bronchial epithelial (HBE) cells and in mouse airways. PM was endocytosed by HBE cells and simultaneously triggered autophagosomes, which then engulfed the invading particles to form amphisomes and subsequent autolysosomes. Genetic blockage of autophagy markedly reduced PM-induced expression of inflammatory cytokines, e.g. IL8 and IL6, and MUC5AC in HBE cells. Mice with impaired autophagy due to knockdown of autophagy-related gene Becn1 or Lc3b displayed significantly reduced airway inflammation and mucus hyperproduction in response to PM exposure in vivo. Interference of the autophagic flux by lysosomal inhibition resulted in accumulated autophagosomes/amphisomes, and intriguingly, this process significantly aggravated the IL8 production through NFKB1, and markedly attenuated MUC5AC expression via activator protein 1. These data indicate that autophagy is required for PM-induced airway epithelial injury, and that inhibition of autophagy exerts therapeutic benefits for PM-induced airway inflammation and mucus hyperproduction, although they are differentially orchestrated by the autophagic flux.

  10. Reducing ultrafine particle emissions using air injection in wood-burning cookstoves

    SciTech Connect

    Rapp, Vi H.; Caubel, Julien J.; Wilson, Daniel L.; Gadgil, Ashok J.

    2016-06-27

    In order to address the health risks and climate impacts associated with pollution from cooking on biomass fires, researchers have focused on designing new cookstoves that improve cooking performance and reduce harmful emissions, specifically particulate matter (PM). One method for improving cooking performance and reducing emissions is using air injection to increase turbulence of unburned gases in the combustion zone. Although air injection reduces total PM mass emissions, the effect on PM size-distribution and number concentration has not been thoroughly investigated. Using two new wood-burning cookstove designs from Lawrence Berkeley National Laboratory, this research explores the effect of air injection on cooking performance, PM and gaseous emissions, and PM size distribution and number concentration. Both cookstoves were created using the Berkeley-Darfur Stove as the base platform to isolate the effects of air injection. The thermal performance, gaseous emissions, PM mass emissions, and particle concentrations (ranging from 5 nm to 10 μm in diameter) of the cookstoves were measured during multiple high-power cooking tests. Finally, the results indicate that air injection improves cookstove performance and reduces total PM mass but increases total ultrafine (less than 100 nm in diameter) PM concentration over the course of high-power cooking.

  11. Reducing ultrafine particle emissions using air injection in wood-burning cookstoves

    DOE PAGES

    Rapp, Vi H.; Caubel, Julien J.; Wilson, Daniel L.; ...

    2016-06-27

    In order to address the health risks and climate impacts associated with pollution from cooking on biomass fires, researchers have focused on designing new cookstoves that improve cooking performance and reduce harmful emissions, specifically particulate matter (PM). One method for improving cooking performance and reducing emissions is using air injection to increase turbulence of unburned gases in the combustion zone. Although air injection reduces total PM mass emissions, the effect on PM size-distribution and number concentration has not been thoroughly investigated. Using two new wood-burning cookstove designs from Lawrence Berkeley National Laboratory, this research explores the effect of air injectionmore » on cooking performance, PM and gaseous emissions, and PM size distribution and number concentration. Both cookstoves were created using the Berkeley-Darfur Stove as the base platform to isolate the effects of air injection. The thermal performance, gaseous emissions, PM mass emissions, and particle concentrations (ranging from 5 nm to 10 μm in diameter) of the cookstoves were measured during multiple high-power cooking tests. Finally, the results indicate that air injection improves cookstove performance and reduces total PM mass but increases total ultrafine (less than 100 nm in diameter) PM concentration over the course of high-power cooking.« less

  12. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, April 1, 1991--June 30, 1991

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period was devoted to experimental design and fabrication tasks.

  13. Modeling ultrafine particle growth at a pine forest site influenced by anthropogenic pollution during BEACHON-RoMBAS 2011

    NASA Astrophysics Data System (ADS)

    Cui, Y. Y.; Hodzic, A.; Smith, J. N.; Ortega, J.; Brioude, J.; Matsui, H.; Turnipseed, A.; Winkler, P.; de Foy, B.

    2014-03-01

    Formation and growth of ultrafine particles is crudely represented in chemistry-climate models, which contributes to uncertainties in aerosol composition, size distribution, and aerosol effects on cloud condensation nuclei (CCN) concentrations. Measurements of ultrafine particles, their precursor gases, and meteorological parameters were performed in a ponderosa pine forest in the Colorado Front Range in July-August 2011, and were analyzed to study processes leading to Aitken-mode Particle burst Events (APEs). These measurements suggest that APEs were associated with the arrival at the site of anthropogenic pollution plumes around noon or in the early afternoon. Number concentrations of ultrafine (4 to 30 nm diameter) particles typically exceeded 10 000 cm-3 during APEs, and these elevated concentrations coincided with increased SO2 and monoterpene concentrations, and led to a factor of two increase in CCN concentrations at 0.5% supersaturation. The APEs were simulated using the regional WRF-Chem model, which was extended to account for ultrafine particle sizes starting at 1 nm in diameter, to include an empirical activation nucleation scheme in the planetary boundary layer, and to explicitly simulate the subsequent growth of Aitken particles by condensation of organic and inorganic vapors. Comparisons with aerosol size distribution measurements showed that simulations using the activation nucleation parameterization reasonably captured aerosol number concentrations and size distribution during APEs, as well as ground level CCN concentrations. Results suggest that sulfuric acid from anthropogenic SO2 triggers APEs, and that the condensation of monoterpene oxidation products onto freshly nucleated particles drives their growth. The simulated growth rate of 3.4 nm h-1 for small particles (4-30 nm in diameter) was comparable to the measured average value of 2.3 nm h-1. Model results also suggest that the presence of APEs tends to modify the composition of sub-100 nm

  14. Modelling component evaporation and composition change of traffic-induced ultrafine particles during travel from street canyon to urban background.

    PubMed

    Nikolova, Irina; MacKenzie, A Rob; Cai, Xiaoming; Alam, Mohammed S; Harrison, Roy M

    2016-07-18

    We developed a model (CiTTy-Street-UFP) of traffic-related particle behaviour in a street canyon and in the nearby downwind urban background that accounts for aerosol dynamics and the variable vapour pressure of component organics. The model simulates the evolution and fate of traffic generated multicomponent ultrafine particles (UFP) composed of a non-volatile core and 17 Semi-Volatile Organic Compounds (SVOC, modelled as n-alkane proxies). A two-stage modelling approach is adopted: (1) a steady state simulation inside the street canyon is achieved, in which there exists a balance between traffic emissions, condensation/evaporation, deposition, coagulation and exchange with the air above roof-level; and (2) a continuing simulation of the above-roof air parcel advected to the nearby urban park during which evaporation is dominant. We evaluate the component evaporation and associated composition changes of multicomponent organic particles in realistic atmospheric conditions and compare our results with observations from London (UK) in a street canyon and an urban park. With plausible input conditions and parameter settings, the model can reproduce, with reasonable fidelity, size distributions in central London in 2007. The modelled nucleation-mode peak diameter, which is 23 nm in the steady-state street canyon, decreases to 9 nm in a travel time of just 120 s. All modelled SVOC in the sub-10 nm particle size range have evaporated leaving behind only non-volatile material, whereas modelled particle composition in the Aitken mode contains SVOC between C26H54 and C32H66. No data on particle composition are available in the study used for validation, or elsewhere. Measurements addressing in detail the size resolved composition of the traffic emitted UFP in the atmosphere are a high priority for future research. Such data would improve the representation of these particles in dispersion models and provide the data essential for model validation. Enhanced knowledge of the

  15. Field comparison of instruments for exposure assessment of airborne ultrafine particles and particulate matter

    NASA Astrophysics Data System (ADS)

    Spinazzè, Andrea; Fanti, Giacomo; Borghi, Francesca; Del Buono, Luca; Campagnolo, Davide; Rovelli, Sabrina; Cattaneo, Andrea; Cavallo, Domenico M.

    2017-04-01

    The objective of this study was to compare the use of co-located real-time devices and gravimetric samplers to measure ultrafine particles (UFP) and size-fractionated PM mass concentrations. The results contribute to evaluating the comparability of different monitoring instruments for size-fractionated PM concentrations. Paired light scattering devices and gravimetric samplers were used to measure the PM1, PM2.5, PM4/5, PM10 and TSP mass concentrations during 8-h monitoring sessions in an urban background site (Como, Italy) in winter. A total of 16 sampling sessions were performed: measurements were analyzed using linear regression analysis. Absolute deviations between techniques were calculated and discussed. The UFP concentrations measured using a condensation particle counter were clearly overestimated compared with the reference instrument (portable diffusion charger), with an absolute deviation that appeared to increase with the UFP concentration. The comparison of different light-scattering devices (photometers - 'PHOTs') indicated an over-estimation of two of the tested instruments (PHOT-2 and PHOT-3) with respect to the one used as the reference (PHOT-1) regarding the measurement of the size-fractioned PM, with the only exception being PM4/5. Further, the comparison of different light-scattering devices with filter-based samplers indicated that direct-reading devices tend to over-estimate (PHOT-2, PHOT-3) or under-estimate (PHOT-1) the PM concentrations from gravimetric analysis. The comparison of different filter-based samplers showed that the observed over-estimation error increased with increasing PM concentration levels; however, the good level of agreement between the investigated methods allowed them to be classified as comparable, although they cannot be characterized as having reciprocal predictability. Ambient relative humidity was correlated with the absolute error resulting from the comparison of direct-reading vs. filter-based techniques, as

  16. The effects of roadside structures on the transport and dispersion of ultrafine particles from highways

    NASA Astrophysics Data System (ADS)

    Bowker, George E.; Baldauf, Richard; Isakov, Vlad; Khlystov, Andrey; Petersen, William

    Understanding local-scale transport and dispersion of pollutants emitted from traffic sources is important for urban planning and air quality assessments. Predicting pollutant concentration patterns in complex environments depends on accurate representations of local features (e.g., noise barriers, trees, buildings) affecting near-field air flows. This study examined the effects of roadside barriers on the flow patterns and dispersion of pollutants from a high-traffic highway in Raleigh, North Carolina, USA. The effects of the structures were analyzed using the Quick Urban & Industrial Complex (QUIC) model, an empirically based diagnostic tool which simulates fine-scale wind field and dispersion patterns around obstacles. Model simulations were compared with the spatial distributions of ultrafine particles (UFP) from vehicular emissions measured using a passenger van equipped with a Differential Mobility Analyzer/Condensation Particle Counter. The field site allowed for an evaluation of pollutant concentrations in open terrain, with a noise barrier present near the road, and with a noise barrier and vegetation present near the road. Results indicated that air pollutant concentrations near the road were generally higher in open terrain situations with no barriers present; however, concentrations for this case decreased faster with distance than when roadside barriers were present. The presence of a noise barrier and vegetation resulted in the lowest downwind pollutant concentrations, indicating that the plume under this condition was relatively uniform and vertically well-mixed. Comparison of the QUIC model with the mobile UFP measurements indicated that QUIC reasonably represented pollutant transport and dispersion for each of the study configurations.

  17. Concentration levels and source apportionment of ultrafine particles in road microenvironments

    NASA Astrophysics Data System (ADS)

    Argyropoulos, G.; Samara, C.; Voutsa, D.; Kouras, A.; Manoli, E.; Voliotis, A.; Tsakis, A.; Chasapidis, L.; Konstandopoulos, A.; Eleftheriadis, K.

    2016-03-01

    A mobile laboratory unit (MOBILAB) with on-board instrumentation (Scanning Mobility Particle Sizer, SMPS; Ambient NOx analyzer) was used to measure size-resolved particle number concentrations (PNCs) of quasi-ultrafine particles (UFPs, 9-372 nm), along with NOx, in road microenvironments. On-road measurements were carried out in and around a large Greek urban agglomeration, the Thessaloniki Metropolitan Area (TMA). Two 2-week measurement campaigns were conducted during the warm period of 2011 and the cold period of 2012. During each sampling campaign, MOBILAB was driven through a 5-day inner-city route and a second 5-day external route covering in total a wide range of districts (urban, urban background, industrial and residential), and road types (major and minor urban roads, freeways, arterial and interurban roads). All routes were conducted during working days, in morning and in afternoon hours under real-world traffic conditions. Spatial classification of MOBILAB measurements involved the assignment of measurement points to location bins defined by the aspect ratio of adjacent urban street canyons (USCs). Source apportionment was further carried out, by applying Positive Matrix Factorization (PMF) to particle size distribution data. Apportioned PMF factors were interpreted, by employing a two-step methodology, which involved (a) statistical association of PMF factor contributions with 12 h air-mass back-trajectories ending at the TMA during MOBILAB measurements, and (b) Multiple Linear Regression (MLR) using PMF factor contributions as the dependent variables, while relative humidity, solar radiation flux, and vehicle speed were used as the independent variables. The applied data analysis showed that low-speed cruise and high-load engine operation modes are the two dominant sources of UFPs in most of the road microenvironments in the TMA, with significant contributions from background photochemical processes during the warm period, explaining the reversed

  18. Ultrafine particle concentrations in the surroundings of an urban area: comparing downwind to upwind conditions using Generalized Additive Models (GAMs).

    PubMed

    Sartini, Claudio; Zauli Sajani, Stefano; Ricciardelli, Isabella; Delgado-Saborit, Juana Mari; Scotto, Fabiana; Trentini, Arianna; Ferrari, Silvia; Poluzzi, Vanes

    2013-10-01

    The aim of this study was to investigate the influence of an urban area on ultrafine particle (UFP) concentration in nearby surrounding areas. We assessed how downwind and upwind conditions affect the UFP concentration at a site placed a few kilometres from the city border. Secondarily, we investigated the relationship among other meteorological factors, temporal variables and UFP. Data were collected for 44 days during 2008 and 2009 at a rural site placed about 3 kilometres from Bologna, in northern Italy. Measurements were performed using a spectrometer (FMPS TSI 3091). The average UFP number concentration was 11 776 (±7836) particles per cm(3). We analysed the effect of wind direction in a multivariate Generalized Additive Model (GAM) adjusted for the principal meteorological parameters and temporal trends. An increase of about 25% in UFP levels was observed when the site was downwind of the urban area, compared with the levels observed when wind blew from rural areas. The size distribution of particles was also affected by the wind direction, showing higher concentration of small size particles when the wind blew from the urban area. The GAM showed a good fit to the data (R(2) = 0.81). Model choice was via Akaike Information Criteria (AIC). The analysis also revealed that an approach based on meteorological data plus temporal trends improved the goodness of the fit of the model. In addition, the findings contribute to evidence on effects of exposure to ultrafine particles on a population living in city surroundings.

  19. Seasonality of ultrafine and sub-micron aerosols and the inferences on particle formation processes

    NASA Astrophysics Data System (ADS)

    Cheung, H. C.; Chou, C. C.-K.; Chen, M.-J.; Huang, W.-R.; Huang, S.-H.; Tsai, C.-Y.; Lee, C. S.-L.

    2015-08-01

    The aim of this study is to investigate the seasonal variations in the physicochemical properties of atmospheric ultrafine particles (UFPs, d ≤ 100nm) and submicron particles (PM1, d ≤ 1 μm) in an East-Asian urban area, which are hypothesized to be affected by the interchange of summer and winter monsoons. An observation experiment was conducted at the TARO, an urban aerosol station in Taipei, Taiwan, from October 2012 to August 2013. The measurements included the mass concentration and chemical composition of UFPs and PM1, as well as the particle number concentration (PNC) and size distribution (PSD) with size range of 4-736 nm. The results indicate that the mass concentration of PM1 was elevated during cold seasons with peak level of 18.5 μg m-3 in spring, whereas the highest UFPs concentration was measured in summertime with a seasonal mean of 1.62 μg m-3. Moreover, chemical analysis revealed that the UFPs and PM1 were characterized by distinct composition; UFPs were composed mostly of organics, whereas ammonium and sulfate were the major constituents in PM1. The seasonal median of total PNCs ranged from 13.9 × 103 cm-3 in autumn to 19.4 × 103 cm-3 in spring. The PSD information retrieved from the corresponding PNC measurements indicates that the nucleation mode PNC (N4-25) peaked at 11.6 × 103 cm-3 in winter, whereas the Aitken mode (N25-100) and accumulation mode (N100-736) exhibited summer maxima at 6.0 × 103 and 3.1 × 103 cm-3, respectively. The shift in PSD during summertime is attributed to the enhancement in the photochemical production of condensable organic matter that, in turn, contributes to the growth of aerosol particles in the atmosphere. In addition, remarkable photochemical production of particles was observed in spring and summer seasons, which was characterized with averaged particle growth and formation rates of 4.3 ± 0.8 nm h-1 and 1.6 ± 0.8 cm-3 s-1, respectively. The prevalence of new particle formation (NPF) in summer is

  20. Translocation of Inhaled Ultrafine Manganese Oxide Particles to the Central Nervous System

    PubMed Central

    Elder, Alison; Gelein, Robert; Silva, Vanessa; Feikert, Tessa; Opanashuk, Lisa; Carter, Janet; Potter, Russell; Maynard, Andrew; Ito, Yasuo; Finkelstein, Jacob; Oberdörster, Günter

    2006-01-01

    Background Studies in monkeys with intranasally instilled gold ultrafine particles (UFPs; < 100 nm) and in rats with inhaled carbon UFPs suggested that solid UFPs deposited in the nose travel along the olfactory nerve to the olfactory bulb. Methods To determine if olfactory translocation occurs for other solid metal UFPs and assess potential health effects, we exposed groups of rats to manganese (Mn) oxide UFPs (30 nm; ~ 500 μg/m3) with either both nostrils patent or the right nostril occluded. We analyzed Mn in lung, liver, olfactory bulb, and other brain regions, and we performed gene and protein analyses. Results After 12 days of exposure with both nostrils patent, Mn concentrations in the olfactory bulb increased 3.5-fold, whereas lung Mn concentrations doubled; there were also increases in striatum, frontal cortex, and cerebellum. Lung lavage analysis showed no indications of lung inflammation, whereas increases in olfactory bulb tumor necrosis factor-α mRNA (~ 8-fold) and protein (~ 30-fold) were found after 11 days of exposure and, to a lesser degree, in other brain regions with increased Mn levels. Macrophage inflammatory protein-2, glial fibrillary acidic protein, and neuronal cell adhesion molecule mRNA were also increased in olfactory bulb. With the right nostril occluded for a 2-day exposure, Mn accumulated only in the left olfactory bulb. Solubilization of the Mn oxide UFPs was < 1.5% per day. Conclusions We conclude that the olfactory neuronal pathway is efficient for translocating inhaled Mn oxide as solid UFPs to the central nervous system and that this can result in inflammatory changes. We suggest that despite differences between human and rodent olfactory systems, this pathway is relevant in humans. PMID:16882521

  1. Measurements and predictors of on-road ultrafine particle concentrations and associated pollutants in Los Angeles

    NASA Astrophysics Data System (ADS)

    Fruin, S.; Westerdahl, D.; Sax, T.; Sioutas, C.; Fine, P. M.

    Motor vehicles are the dominant source of oxides of nitrogen (NO x), particulate matter (PM), and certain air toxics (e.g., benzene, 1,3-butadiene) in urban areas. On roadways, motor vehicle-related pollutant concentrations are typically many times higher than ambient concentrations. Due to high air exchange rates typical of moving vehicles, this makes time spent in vehicles on roadways a major source of exposure. This paper presents on-road measurements for Los Angeles freeways and arterial roads taken from a zero-emission electric vehicle outfitted with real-time instruments. The objective was to characterize air pollutant concentrations on roadways and identify the factors associated with the highest concentrations. Our analysis demonstrated that on freeways, concentrations of ultrafine particles (UFPs), black carbon, nitric oxide, and PM-bound polycyclic aromatic hydrocarbons (PM-PAH) are generated primarily by diesel-powered vehicles, despite the relatively low fraction (˜6%) of diesel-powered vehicles on Los Angeles freeways. However, UFP concentrations on arterial roads appeared to be driven primarily by proximity to gasoline-powered vehicles undergoing hard accelerations. Concentrations were roughly one-third of those on freeways. By using a multiple regression model for the freeway measurements, we were able to explain 60-70% of the variability in concentrations of UFP, black carbon, nitric oxide, and PM-PAH using measures of diesel truck density and hour of day (as an indicator of wind speed). Freeway concentrations of these pollutants were also well correlated with readily available annual average daily truck counts, potentially allowing improved population exposure estimates for epidemiology studies. Based on these roadway measurements and average driving time, it appears that 33-45% of total UFP exposure for Los Angeles residents occurs due to time spent traveling in vehicles.

  2. Land use regression modeling of ultrafine particles, ozone, nitrogen oxides and markers of particulate matter pollution in Augsburg, Germany.

    PubMed

    Wolf, Kathrin; Cyrys, Josef; Harciníková, Tatiana; Gu, Jianwei; Kusch, Thomas; Hampel, Regina; Schneider, Alexandra; Peters, Annette

    2017-02-01

    Important health relevance has been suggested for ultrafine particles (UFP) and ozone, but studies on long-term effects are scarce, mainly due to the lack of appropriate spatial exposure models. We designed a measurement campaign to develop land use regression (LUR) models to predict the spatial variability focusing on particle number concentration (PNC) as indicator for UFP, ozone and several other air pollutants in the Augsburg region, Southern Germany. Three bi-weekly measurements of PNC, ozone, particulate matter (PM10, PM2.5), soot (PM2.5abs) and nitrogen oxides (NOx, NO2) were performed at 20 sites in 2014/15. Annual average concentration were calculated and temporally adjusted by measurements from a continuous background station. As geographic predictors we offered several traffic and land use variables, altitude, population and building density. Models were validated using leave-one-out cross-validation. Adjusted model explained variance (R(2)) was high for PNC and ozone (0.89 and 0.88). Cross-validation adjusted R(2) was slightly lower (0.82 and 0.81) but still indicated a very good fit. LUR models for other pollutants performed well with adjusted R(2) between 0.68 (PMcoarse) and 0.94 (NO2). Contrary to previous studies, ozone showed a moderate correlation with NO2 (Pearson's r=-0.26). PNC was moderately correlated with ozone and PM2.5, but highly correlated with NOx (r=0.91). For PNC and NOx, LUR models comprised similar predictors and future epidemiological analyses evaluating health effects need to consider these similarities.

  3. Comparison Between Different Processing Schedules for the Development of Ultrafine-Grained Dual-Phase Steel

    NASA Astrophysics Data System (ADS)

    Karmakar, Anish; Sivaprasad, S.; Nath, S. K.; Misra, R. D. K.; Chakrabarti, Debalay

    2014-05-01

    A comparative study was carried out on the development of ultrafine-grained dual-phase (DP) (ferrite-martensite) structures in a low-carbon microalloyed steel processed using two thermomechanical processing routes, (i) intercritical deformation and (ii) warm-deformation and intercritical annealing. The samples were deformed using Gleeble3500® simulator, maintaining a constant total strain ( ɛ = 1) and strain rate ( = 1/s). Evolution of microstructure and micro-texture was investigated by SEM, TEM, and EBSD. Ultrafine-grained DP structures could be formed by careful selection of deformation temperature, T def (for intercritical deformation) or annealing temperature, T anneal (for warm-deformation and annealing). Overall, the ferrite grain sizes ranged from 1.5 to 4.0 μm, and the sizes and fractions of the uniformly distributed fine-martensitic islands ranged from 1.5 to 3.0 μm and 15 to 45 pct, respectively. Dynamic strain-induced austenite-to-ferrite transformation followed by continuous (dynamic) recrystallization of the ferrite dictated the grain refinement during intercritical deformation, while, continuous (static) recrystallization by pronounced recovery dictated the grain refinement during the warm-deformation and the annealing. Regarding intercritical deformation, the samples cooled to T def indicated finer grain size compared with the samples heated to T def, which are explained in terms of the effects of strain partitioning on the ferrite and the heating during deformation. Alpha-fiber components dominated the texture in all the samples, and the fraction of high-angle boundaries (with >15 deg misorientation) increased with the increasing T def or T anneal, depending on the processing schedule. Fine carbide particles, microalloyed precipitates and austenitic islands played important roles in defining the mechanism of grain refinement that involved retarding conventional ferrite recrystallization and ferrite grain growth. With regard to the intercritical

  4. A novel low-temperature preparation of Ni-Zn ferrite and the properties of the ultrafine particles formed

    NASA Astrophysics Data System (ADS)

    Chen, C. J.; Bridger, K.; Winzer, S. R.; PaiVerneker, V.

    1988-04-01

    Ultrafine particles of nickel-zinc ferrite have been formed from solutions of metal nitrates by coprecipitation with hydrazine, followed by aging at 90 °C. The crystallites either aggregate into much larger clusters or form single particles, depending upon the preparation conditions, and vary in size from 30 to ≊300 Å. Saturation magnetizations (Ms) of the ferrites varied from 40 to 65 emu/g and the coercivities from 1 to ≊100 Oe. Increasing hydrazine concentrations tended to produce particles with lower Ms. However, for hydrazine/metal ratios below unity, decreasing the hydrazine concentration dramatically lowered the Ms value. Particles formed without hydrazine (e.g., by aging hydroxides precipitated with potassium hydroxide) did not appear to be magnetic. Variations of the magnetic properties and lattice parameters as a function of preparation conditions will be discussed.

  5. Transition metals in coarse, fine, very fine and ultra-fine particles from an interstate highway transect near Detroit

    NASA Astrophysics Data System (ADS)

    Cahill, Thomas A.; Barnes, David E.; Lawton, Jonathan A.; Miller, Roger; Spada, Nicholas; Willis, Robert D.; Kimbrough, Sue

    2016-11-01

    As one component of a study investigating the impact of vehicle emissions on near-road air quality, human exposures, and potential health effects, particles were measured from September 21 to October 30, 2010 on both sides of a major roadway (Interstate-96) in Detroit. Traffic moved freely on this 12 lane freeway with a mean velocity of 69 mi/hr. with little braking and acceleration. The UC Davis DELTA Group rotating drum (DRUM) impactors were used to collect particles in 8 size ranges at sites nominally 100 m south, 10 m north, 100 m north, and 300 m north of the highway. Ultra-fine particles were continuously collected at the 10 m north and 100 m north sites. Samples were analyzed every 3 h for mass (soft beta ray transmission), 42 elements (synchrotron-induced x-ray fluorescence) and optical attenuation (350-800 nm spectroscopy). A three day period of steady southerly winds along the array allowed direct measurement of freeway emission rates for coarse (10 > Dp > 1.0 μm), PM2.5, very fine (0.26 > Dp > 0.09 μm), and ultra-fine (Dp < 0.09 μm) particles. The PM2.5 mass concentrations were modeled using literature emission rates during the south to north wind periods, and averaged 1.6 ± 0.5 μg/m3, versus the measured value of 2.0 ± 0.7 μg/m3. Using European freeway emission rates from 2010, and modeling them at the I-96 site, we would predict roughly 3.1 μg/m3 of PM2.5 particles, corrected from the 4.9 PM10 value by their measured road dust contributions. Using California car and truck emission rates of 1973, this value would have been about 16 μg/m3, corrected down from the 19 μg/m3 PM5.0 using measured roadway dust contributions. This would have included 2.7 μg/m3 of lead, versus the 0.0033 μg/m3 measured. Very fine particles were distributed across the array with a relatively weak falloff versus distance. For the ultra-fine particles, emissions of soot and metals seen in vehicular braking studies correlated with traffic at the 10 m site, but only the

  6. TRANSLOCATION AND POTENTIAL NEUROLOGICAL EFFECTS OF FINE AND ULTRAFINE PARTICLES: A CRITICAL UPDATE

    EPA Science Inventory

    This proceedings book is a collection of seminars presented in a symposium organized by by Munich's GSF-National Research Center for Environment and Health. Research presented at this symposium indicated inhaled ultrafine particulate matter quickly exits the lungs and target...

  7. Personal exposure of street canyon intersection users to PM 2.5, ultrafine particle counts and carbon monoxide in Central London, UK

    NASA Astrophysics Data System (ADS)

    Kaur, S.; Nieuwenhuijsen, M.; Colvile, R.

    Short-term human exposure to PM 2.5, ultrafine particle counts (particle range: 0.02-1 μm) and carbon monoxide (CO) was investigated at and around a street canyon intersection in Central London, UK. During a four-week field campaign, groups of four volunteers collected samples at three timings (morning, lunch and afternoon), along two different routes (a heavily trafficked route and a backstreet route) via five modes of transport (walking, cycling, bus, car and taxi). PM 2.5 was sampled using high-flow gravimetric personal samplers, ultrafine particle counts were measured using TSI P-TRAKs and Langans were used to measure CO exposure. Three hundred and ninety-four samples were collected—197 PM 2.5, 86 ultrafine particle count and 111 CO. Arithmetic means of PM 2.5 personal exposure were 27.5, 33.5, 34.5, 38.0 and 41.5 μg m -3, ultrafine particle counts were 67 773, 93 968, 101 364, 99 736 and 87 545 pt cm -3 and CO levels were 0.9, 1.1, 0.8, 1.3 and 1.1 ppm for walking, cycling, bus, car and taxi respectively. On the heavily trafficked route, personal exposure was 35.3 μg m -3, 101142 pt cm -3 and 1.3 ppm, and on the backstreet route it was 31.8 μg m -3, 71628 pt cm -3 and 0.6 ppm for PM 2.5, ultrafine particle counts and CO, respectively. Personal exposure levels were high during the morning measurements for all three pollutants (34.6 μg m -3, 106 270 pt cm -3 and 1.5 ppm for PM 2.5, ultrafine particle counts and CO, respectively).There was a moderately strong correlation between personal exposure of ultrafine particle counts and CO ( r=0.7, N=67) but a weaker correlation between PM 2.5 and ultrafine particle counts ( r=0.5, N=83) and a low correlation between PM 2.5 and CO exposure ( r=0.2, N=105). The exposure assessment also revealed that the background and kerbside monitoring stations were not representative of the personal exposure of individuals to PM 2.5 and CO at and around a street canyon intersection.

  8. Physicochemical properties and ability to generate free radicals of ambient coarse, fine, and ultrafine particles in the atmosphere of Xuanwei, China, an area of high lung cancer incidence

    NASA Astrophysics Data System (ADS)

    Lu, Senlin; Yi, Fei; Hao, Xiaojie; Yu, Shang; Ren, Jingjing; Wu, Minghong; Jialiang, Feng; Yonemochi, Shinich; Wang, Qingyue

    2014-11-01

    The link between the high incidence of lung cancer and harmful pollutants emitted by local coal combustion in Xuanwei, Yunnan province, China, has been a focus of study since the 1980s. However, the mechanisms responsible for the high lung cancer rate remain unclear, necessitating further study. Since a close relationship between ambient air particle pollution and respiratory diseases exists, we sampled size-resolved ambient particles from the atmosphere of Xuanwei. In our indoor experiment, cutting-edge methods, including scanning electron microscopy coupled with energy dispersive X-ray detection (SEM/EDX), particle-induced X-ray emission (PIXE), electronic paramagnetic resonance (EPR) and the cell-free DCFH-DA assay, were employed to investigate the physicochemical properties, the potential to generate free radicals and the oxidative potential of ambient coarse (diameter, 1.8-10 μm), fine (diameter, 0.1-1.8 μm), and ultrafine (diameter, <0.1 μm) particles. We found the total mass concentrations of the size-resolved particles collected in spring were higher than that in early winter. Mass percentage of fine particles accounted for 68% and 61% of the total particulate mass in spring and in early winter samples, respectively, indicating that fine particles were the major component of the Xuanwei ambient particulate matters. On the other hand, the results of SEM/EDX analysis showed that the coarse particles were dominated by minerals, the fine particles by soot aggregates and fly ashes, and the ultrafine particles by soot particles and unidentified particles. Our PIXE results revealed that crustal elements (Ca, Ti Si, Fe) were mainly distributed in coarse particles, while trace metals (Cr, Mn, Ni, Cu, Zn, Pb) dominated in the fine particle fraction, and S, a typical element emitted by coal combustion, mainly resided in fine particles collected from the winter atmosphere. EPR results indicated that the magnitude of free radical intensity caused by size

  9. Characterizing ultrafine particles and other air pollutants in and around school buses.

    PubMed

    Zhu, Yifang; Zhang, Qunfang

    2014-03-01

    Increasing evidence has demonstrated toxic effects of ultrafine particles (UFP*, diameter < 100 nm). Children are particularly at risk because of their immature respiratory systems and higher breathing rates per body mass. This study aimed to characterize UFP, PM2.5 (particulate matter < or = 2.5 microm in aerodynamic diameter), and other vehicular-emitted pollutants in and around school buses. Four sub-studies were conducted, including: 1. On-road tests to measure in-cabin air pollutant levels while school buses were being driven; 2. Idling tests to determine the contributions of tailpipe emissions from idling school buses to air pollutant levels in and around school buses under different scenarios; 3. Retrofit tests to evaluate the performance of two retrofit systems, a diesel oxidation catalyst (DOC) muffler and a crankcase filtration system (CFS), on reducing tailpipe emissions and in-cabin air pollutant concentrations under idling and driving conditions; and 4. High efficiency particulate air (HEPA) filter air purifier tests to evaluate the effectiveness of in-cabin filtration. In total, 24 school buses were employed to cover a wide range of school buses commonly used in the United States. Real-time air quality measurements included particle number concentration (PNC), fine and UFP size distribution in the size range 7.6-289 nm, PM2.5 mass concentration, black carbon (BC) concentration, and carbon monoxide (CO) and carbon dioxide (CO2) concentrations. For in-cabin measurements, instruments were placed on a platform secured to the rear seats inside the school buses. For all other tests, a second set of instruments was deployed to simultaneously measure the ambient air pollutant levels. For tailpipe emission measurements, the exhaust was diluted and then measured by instruments identical to those used for the in-cabin measurements. The results show that when driving on roads, in-cabin PNC, fine and UFP size distribution, PM2.5, BC, and CO varied by engine age

  10. Activation of endothelial cells after exposure to ambient ultrafine particles: The role of NADPH oxidase

    SciTech Connect

    Mo Yiqun; Wan Rong; Chien Sufan; Tollerud, David J.; Zhang Qunwei

    2009-04-15

    Several studies have shown that ultrafine particles (UFPs) may pass from the lungs to the circulation because of their very small diameter, and induce lung oxidative stress with a resultant increase in lung epithelial permeability. The direct effects of UFPs on vascular endothelium remain unknown. We hypothesized that exposure to UFPs leads to endothelial cell O{sub 2}{sup {center_dot}}{sup -} generation via NADPH oxidase and results in activation of endothelial cells. Our results showed that UFPs, at a non-toxic dose, induced reactive oxygen species (ROS) generation in mouse pulmonary microvascular endothelial cells (MPMVEC) that was inhibited by pre-treatment with the ROS scavengers or inhibitors, but not with the mitochondrial inhibitor, rotenone. UFP-induced ROS generation in MPMVEC was abolished by p67{sup phox} siRNA transfection and UFPs did not cause ROS generation in MPMVEC isolated from gp91{sup phox} knock-out mice. UFP-induced ROS generation in endothelial cells was also determined in vivo by using a perfused lung model with imaging. Moreover, Western blot and immunofluorescence staining results showed that MPMVEC treated with UFPs resulted in the translocation of cytosolic proteins of NADPH oxidase, p47{sup phox}, p67{sup phox} and rac 1, to the plasma membrane. These results demonstrate that NADPH oxidase in the pulmonary endothelium is involved in ROS generation following exposure to UFPs. To investigate the activation of endothelial cells by UFP-induced oxidative stress, we determined the activation of the mitogen-activated protein kinases (MAPKs) in MPMVEC. Our results showed that exposure of MPMVEC to UFPs caused increased phosphorylation of p38 and ERK1/2 MAPKs that was blocked by pre-treatment with DPI or p67{sup phox} siRNA. Exposure of MPMVEC obtained from gp91{sup phox} knock-out mice to UFPs did not cause increased phosphorylation of p38 and ERK1/2 MAPKs. These findings confirm that UFPs can cause endothelial cells to generate ROS directly

  11. Water-soluble ions in nano/ultrafine/fine/coarse particles collected near a busy road and at a rural site.

    PubMed

    Lin, Chih-Chung; Chen, Shui-Jen; Huang, Kuo-Lin; Lee, Wen-Jhy; Lin, Wen-Yinn; Liao, Chiu-Jung; Chaung, Hso-Chi; Chiu, Chuen-Huey

    2007-01-01

    This study investigated water-soluble ions in the sized particles (particularly nano (PM(0.01-0.056))/ultrafine (PM(0.01-0.1))) collected using MOUDI and Nano-MOUDI samplers near a busy road site and at a rural site. The analytical results demonstrate that nano and coarse particles exhibited the highest (16.3%) and lowest (8.37%) nitrate mass ratios, respectively. The mass ratio of NO(3)(-) was higher than that of SO(4)(2-) in all the sized particles at the traffic site. The secondary aerosols all displayed trimodal distributions. The aerosols in ultrafine particles collected at the roadside site exhibited Aitken mode distributions indicating they were of local origin. This finding was not observed for those ultrafine particles collected at the rural site. The mass median diameters (MMDs) of the nano, ultrafine, and fine particles were smaller at the traffic site than at the rural site, possibly related to the contribution of mobile engine emissions.

  12. Ultrafine particles from electric appliances and cooking pans: experiments suggesting desorption/nucleation of sorbed organics as the primary source.

    PubMed

    Wallace, L A; Ott, W R; Weschler, C J

    2015-10-01

    Ultrafine particles are observed when metal surfaces, such as heating elements in electric appliances, or even empty cooking pans, are heated. The source of the particles has not been identified. We present evidence that particles >10 nm are not emitted directly from the heating elements or the metal surfaces. Using repeated heating of an electric burner, several types of cooking pans, and a steam iron, the increase in the number of particles (>10 nm) can be reduced to 0. After the devices are exposed to indoor air for several hours or days, subsequent heating results in renewed particle production, suggesting that organic matter has sorbed on their surfaces. Also, after a pan has been heated to the point that no increase in particles is observed, washing with detergent results in copious production of particles the next time the pan is heated. These observations suggest that detergent residue and organics sorbed from indoor air are the sources of the particles. We hypothesize that organic compounds are thermally desorbed from the hot surface as gaseous molecules; as they diffuse from the hot air near the pan into cooler air, selected compounds exceed their saturation concentration and nucleation occurs.

  13. Aircraft observations of ultrafine particles and CCN from the boundary layer to the free troposphere in the Arctic summertime

    NASA Astrophysics Data System (ADS)

    Burkart, Julia; Willis, Megan; Bozem, Heiko; Hoor, Peter; Köllner, Franziska; Schneider, Johannes; Brauner, Ralf; Konrad, Christian; Herber, Andreas; Leaitch, Richard; Abbatt, Jon

    2016-04-01

    The Arctic is one of the regions most sensitive to climate change. The shrinking extent of sea ice during the Arctic summertime increases the area covered by open ocean, which likely impacts Arctic aerosol, cloud properties, and thus climate. In this context extensive aerosol measurements (aerosol composition, particle number and size, cloud condensation nuclei, and trace gases) have been made during the NETCARE 2014 summer campaign from the Polar 6 aircraft. The Polar 6 is an adopted DC-3 aircraft owned by the Alfred Wegener Institute in Bremerhaven, Germany. In July 2014 eleven flights were conducted out of Resolute Bay. Flights included vertical profiles from as low as 60 m up to 3 km, as well as several low-level flights covering diverse terrains such as open ocean, fast ice, melt ponds, and polynyas. Here we discuss the vertical distribution of ultrafine particles (UFP, dp: 5 - 20 nm), size distributions of larger particles (dp: 20 nm to 1 μm), and cloud condensation nuclei (CCN) in relation to different meteorological conditions and terrains. UFPs have been observed predominantly within the boundary layer, where concentrations reached several hundreds and occasionally even a few thousand particles per cubic centimeter. Highest concentrations were observed above open ocean and at the top of low-level clouds. During such events, the dominant mode of the size distribution was below 20 nm. However, in a few cases this ultrafine mode extended to sizes larger than 40 nm, suggesting that these UFP can grow into the CCN size range and thereby impact cloud properties and become climatically relevant.

  14. The chemical composition of ultrafine particles and associated biological effects at an alpine town impacted by wood burning.

    PubMed

    Corsini, Emanuela; Vecchi, Roberta; Marabini, Laura; Fermo, Paola; Becagli, Silvia; Bernardoni, Vera; Caruso, Donatella; Corbella, Lorenza; Dell'Acqua, Manuela; Galli, Corrado L; Lonati, Giovanni; Ozgen, Senem; Papale, Angela; Signorini, Stefano; Tardivo, Ruggero; Valli, Gianluigi; Marinovich, Marina

    2017-02-25

    This work is part of the TOBICUP (TOxicity of BIomass Combustion generated Ultrafine Particles) project which aimed at providing the composition of ultrafine particles (UFPs, i.e. particles with aerodynamic diameter, dae, lower than 100nm) emitted by wood combustion and elucidating the related toxicity. Results here reported are from two ambient monitoring campaigns carried out at an alpine town in Northern Italy, where wood burning is largely diffused for domestic heating in winter. Wintertime and summertime UFP samples were analyzed to assess their chemical composition (i.e. elements, ions, total carbon, anhydrosugars, and polycyclic aromatic hydrocarbons) and biological activity. The induction of the pro-inflammatory cytokine interleukin-8 (IL-8) by UFPs was investigated in two human cells lines (A549 and THP-1) and in human peripheral blood leukocytes. In addition, UFP-induced oxidative stress and genotoxicity were investigated in A549 cells. Ambient UFP-related effects were compared to those induced by traffic-emitted particles (DEP) taken from the NIES reference material "vehicle exhaust particulates". Ambient air UFPs induced a dose-related IL-8 release in both A549 and THP-1 cells; the effect was more relevant on summer samples and in general THP-1 cells were more sensitive than A549 cells. On a weight basis our data did not support a higher biological activity of ambient UFPs compared to DEP. The production of IL-8 in the whole blood assay indicated that UFPs reached systemic circulation and activated blood leukocytes. Comet assay and γ-H2AX evaluation showed a significant DNA damage especially in winter UFPs samples compared to control samples. Our study showed that ambient UFPs can evoke a pulmonary inflammatory response by inducing a dose-related IL-8 production and DNA damage, with different responses to UFP samples collected in the summer and winter periods.

  15. Inhalation of ultrafine carbon particles alters heart rate and heart rate variability in people with type 2 diabetes

    PubMed Central

    2014-01-01

    Background Diabetes may confer an increased risk for the cardiovascular health effects of particulate air pollution, but few human clinical studies of air pollution have included people with diabetes. Ultrafine particles (UFP, ≤100 nm in diameter) have been hypothesized to be an important component of particulate air pollution with regard to cardiovascular health effects. Methods 17 never-smoker subjects 30–60 years of age, with stable type 2 diabetes but otherwise healthy, inhaled either filtered air (0–10 particles/cm3) or elemental carbon UFP (~107 particles/cm3, ~50 ug/m3, count median diameter 32 nm) by mouthpiece, for 2 hours at rest, in a double-blind, randomized, crossover study design. A digital 12-lead electrocardiogram (ECG) was recorded continuously for 48 hours, beginning 1 hour prior to exposure. Results Analysis of 5-minute segments of the ECG during quiet rest showed reduced high-frequency heart rate variability with UFP relative to air exposure (p = 0.014), paralleled by non-significant reductions in time-domain heart rate variability parameters. In the analysis of longer durations of the ECG, we found that UFP exposure increased the heart rate relative to air exposure. During the 21- to 45-hour interval after exposure, the average heart rate increased approximately 8 beats per minute with UFP, compared to 5 beats per minute with air (p = 0.045). There were no UFP effects on cardiac rhythm or repolarization. Conclusions Inhalation of elemental carbon ultrafine particles alters heart rate and heart rate variability in people with type 2 diabetes. Our findings suggest that effects may occur and persist hours after a single 2-hour exposure. PMID:25028096

  16. Contribution of gas and electric stoves to residential ultrafine particle concentrations between 2 and 64 nm: size distributions and emission and coagulation remission and coagulation rates.

    PubMed

    Wallace, Lance; Wang, Fang; Howard-Reed, Cynthia; Persily, Andrew

    2008-12-01

    Three indoor sources (a gas stove, an electric stove, and an electric toaster oven) of ultrafine particles (UFPs) have been studied in an instrumented test house on the campus of the National Institute of Standards and Technology (NIST). Previous studies have reported the concentration of ultrafine particles indoors due to cooking, but have been limited to particles with diameters greater than 10 nm. New technology now makes it possible to measure particles as small as 2 nm. Therefore, NIST conducted a study to measure typical concentrations and estimate emission rates and coagulation rates of UFPs in the size range from 2 to 64 nm. More than 150 tests were completed. Peak concentrations from the gas and electric stovetop burners/coils occurred at a particle size of approximately 5 nm. Total number concentrations were as much as 10 times greater than reported in previous studies of particle sizes above 10 nm. Because of these high concentrations of very small particles, coagulation was the dominant process affecting the evolution of the size distribution after the source was turned off. The observed number concentration changes due to coagulation were fit by models including corrections for van der Waals and viscosity forces and fractal shapes. Indoor/outdoor ratios indicated that less than 5% of the <10 nm particles penetrated the house. This suggests that outdoor sources of these ultrafine particles will not contribute substantially to human exposure if indoor sources are present.

  17. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, January 1, 1992--March 31, 1992

    SciTech Connect

    Not Available

    1992-05-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period focused on assembling the supercritical particle generation/collection system. Effort was applied to constructing a shakedown testing plan also.

  18. A hybrid chip based on aerodynamics and electrostatics for the size-dependent classification of ultrafine and nano particles.

    PubMed

    Kim, Yong-Ho; Park, Dongho; Hwang, Jungho; Kim, Yong-Jun

    2009-09-21

    Conventional virtual impactors experience a large pressure drop when they classify particles according to size, in particular ultrafine particles smaller than 100 nm in diameter. Therefore, most virtual impactors have been used to classify particles larger than 100 nm. Their cut-off diameters are also fixed by the geometry of their flow channels. In the proposed virtual impactor, particles smaller than 100 nm are accelerated by applying DC potentials to an integrated electrode pair. By the electrical acceleration, the large pressure drop could be significantly decreased and new cut-off diameters smaller than 100 nm could be successfully added. The geometric cut-off diameter (GCD) of the proposed virtual impactor was designed to be 1.0 microm. Performances including the GCD and wall loss were examined by classifying dioctyl sebacate of 100 to 600 nm in size and carbon particles of 0.6 to 10 microm in size. The GCD was measured to be 0.95 microm, and the wall loss was highest at 1.1 microm. To add new cut-off diameters, monodisperse NaCl particles ranging from 15 to 70 nm were classified using the proposed virtual impactor with applying a DC potential of 0.25 to 3.0 kV. In this range of the potential, the new cut-off diameters ranging from 15 to 35 nm was added.

  19. Method for making fine and ultrafine spherical particles of zirconium titanate and other mixed metal oxide systems

    DOEpatents

    Hu, Michael Z.

    2006-05-23

    Disclosed is a method for making amorphous spherical particles of zirconium titanate and crystalline spherical particles of zirconium titanate comprising the steps of mixing an aqueous solution of zirconium salt and an aqueous solution of titanium salt into a mixed solution having equal moles of zirconium and titanium and having a total salt concentration in the range from 0.01 M to about 0.5 M. A stearic dispersant and an organic solvent is added to the mixed salt solution, subjecting the zirconium salt and the titanium salt in the mixed solution to a coprecipitation reaction forming a solution containing amorphous spherical particles of zirconium titanate wherein the volume ratio of the organic solvent to aqueous part is in the range from 1 to 5. The solution of amorphous spherical particles is incubated in an oven at a temperature .ltoreq.100.degree. C. for a period of time .ltoreq.24 hours converting the amorphous particles to fine or ultrafine crystalline spherical particles of zirconium titanate.

  20. The effects of the built environment, traffic patterns, and micrometeorology on street level ultrafine particle concentrations at a block scale: Results from multiple urban sites.

    PubMed

    Choi, Wonsik; Ranasinghe, Dilhara; Bunavage, Karen; DeShazo, J R; Wu, Lisa; Seguel, Rodrigo; Winer, Arthur M; Paulson, Suzanne E

    2016-05-15

    This study attempts to explain explicitly the direct and quantitative effects of complicated urban built-environment on near-road dispersion and levels of vehicular emissions at the scale of several city blocks, based on ultrafine particle concentrations ([UFP]). On short timescales, ultrafine particles are an excellent proxy for other roadway emissions. Five measurement sites in the greater Los Angeles with different built environments but similar mesoscale meteorology were explored. After controlling for traffic, for most sampling days and sites, morning [UFP] were higher than those in the afternoon due to limited dispersion capacity combined with a relatively stable surface layer. [UFP] at the intersection corners were also higher than those over the sampling sites, implying that accelerating vehicles around the intersections contributed to [UFP] elevation. In the calm morning, the areal aspect ratio (Ararea), developed in this study for real urban configurations, showed a strong relationship with block-scale [UFP]. Ararea includes the building area-weighted building height, the amount of open space, and the building footprint. In the afternoon, however, when wind speeds were generally higher and turbulence was stronger, vertical turbulence intensity σw was the most effective factor controlling [UFP]. The surrounding built environment appears to play an indirect role in observed [UFP], by affecting surface level micrometeorology. The effects are substantial; controlling for traffic, differences in Ararea and building heterogeneity were related to differences in [UFP] of factors of two to three among our five study sites. These results have significant implications for pedestrian exposure as well as transit-oriented urban planning.

  1. International Airport Impacts to Air Quality: Size and Related Properties of Large Increases in Ultrafine Particle Number Concentrations.

    PubMed

    Hudda, N; Fruin, S A

    2016-04-05

    We measured particle size distributions and spatial patterns of particle number (PN) and particle surface area concentrations downwind from the Los Angeles International Airport (LAX) where large increases (over local background) in PN concentrations routinely extended 18 km downwind. These elevations were mostly comprised of ultrafine particles smaller than 40 nm. For a given downwind distance, the greatest increases in PN concentrations, along with the smallest mean sizes, were detected at locations under the landing jet trajectories. The smaller size of particles in the impacted area, as compared to the ambient urban aerosol, increased calculated lung deposition fractions to 0.7-0.8 from 0.5-0.7. A diffusion charging instrument (DiSCMini), that simulates alveolar lung deposition, measured a fivefold increase in alveolar-lung deposited surface area concentrations 2-3 km downwind from the airport (over local background), decreasing steadily to a twofold increase 18 km downwind. These ratios (elevated lung-deposited surface area over background) were lower than the corresponding ratios for elevated PN concentrations, which decreased from tenfold to twofold over the same distance, but the spatial patterns of elevated concentrations were similar. It appears that PN concentration can serve as a nonlinear proxy for lung deposited surface area downwind of major airports.

  2. Fine and ultrafine particle exposures on 73 trips by car to 65 non-smoking restaurants in the San Francisco Bay Area.

    PubMed

    Ott, W R; Wallace, L A; McAteer, J M; Hildemann, L M

    2017-01-01

    A number of studies indicate cooking is a major source of exposure to particulate matter, but few studies have measured indoor air pollution in restaurants, where cooking predominates. We made 73 visits by car to 65 different non-smoking restaurants in 10 Northern California towns while carrying portable continuous monitors that unobtrusively measured ultrafine (down to 10 nm) and fine (PM2.5 ) particles to characterize indoor restaurant exposures, comparing them with exposures in the car. The mean ultrafine number concentrations in the restaurants on dinner visits averaging 1.4 h was 71 600 particles/cm(3) , or 4.3 times the mean concentration on car trips, and 12.3 times the mean background concentration in the residence. Restaurants that cooked dinner in the same room as the patrons had higher ultrafine concentrations than restaurants with separate kitchens. Restaurant PM2.5 mass concentrations averaged 36.3 μg/m(3) , ranging from 1.5 to 454 μg/m(3) , but were relatively low on most visits: 43% of the indoor means were below 10 μg/m(3) and 66% were below 20 μg/m(3) , with 5.5% above 100 μg/m(3) . Exposure to fine and ultrafine particles when visiting a restaurant exceeded the exposure a person received while traveling by car to and from the restaurant.

  3. Identification of ultra-fine magnetic particles in weakly magnetic carbonates using time-decay of viscous remanence

    NASA Astrophysics Data System (ADS)

    Chadima, M.; Chadimova, L.

    2015-12-01

    In some geological and environmental processes, such as diagenesis, very low grade metamorphism, pedogenesis, anthropogenic pollution, new ultra-fine magnetic minerals may be formed. The variation in content of these minerals has been routinely investigated by frequency-dependent magnetic susceptibility. Although being quite reliable for most rocks, frequency-dependent susceptibility reaches its limit when applied to very weakly magnetic rock types, e.g. carbonates. Assuming a broad size distribution of the ultra-fine magnetic particles spanning across the SP/SSD boundary we suggest assessing their content by quantification of time-decay of viscous remanent magnetization. Using artificially-imparted magnetization we usually obtain much stronger signal compared to that of magnetic susceptibility. For that purpose we employed a LDA5/PAM1 Pulse Magnetizer coupled with a JR6 Spinner Magnetometer (both manufactured by Agico, Inc.). Both instruments are simultaneously controlled thus they work in the same time frame. Magnetic remanence is measured repeatedly as a function of time and exponential decay curves are fitted on the acquired data and the relative ratio of viscous and non-viscous particles is estimated. The proposed method is tested on two sets of samples representing biostratigraphically well-established sections across Silurian shallow-water limestone facies in the Prague Synform (Czech Republic). Sampling interval comprises so-called Lau Event which belongs to one of the major environmental and biological perturbances in the Phanerozoic Ocean. This level is also associated with very strong geochemical changes, so-called global Middle Ludfordian Carbon Isotope Excursion, recognized in numerous areas worldwide. Other geophysical methods applied include high-resolution magnetic susceptibility measurements and gamma-ray spectrometry, supplemented by rock magnetic measurements (ARM/IRM) and frequency-dependent magnetic susceptibility.

  4. Ultrafine particles in four European urban environments: Results from a new continuous long-term monitoring network

    NASA Astrophysics Data System (ADS)

    Hofman, J.; Staelens, J.; Cordell, R.; Stroobants, C.; Zikova, N.; Hama, S. M. L.; Wyche, K. P.; Kos, G. P. A.; Van Der Zee, S.; Smallbone, K. L.; Weijers, E. P.; Monks, P. S.; Roekens, E.

    2016-07-01

    To gain a better understanding on the spatiotemporal variation of ultrafine particles (UFPs) in urban environments, this study reports on the first results of a long-term UFP monitoring network, set up in Amsterdam (NL), Antwerp (BE), Leicester (UK) and London (UK). Total number concentrations and size distributions were assessed during 1-2 years at four fixed urban background sites, supplemented with mobile trailer measurements for co-location monitoring and additional short-term monitoring sites. Intra- and interurban spatiotemporal UFP variation, associations with commonly-monitored pollutants (PM, NOx and BC) and impacts of wind fields were evaluated. Although comparable size distributions were observed between the four cities, source-related differences were demonstrated within specific particle size classes. Total and size-resolved particle number concentrations showed clear traffic-related temporal variation, confirming road traffic as the major UFP contributor in urban environments. New particle formation events were observed in all cities. Correlations with typical traffic-related pollutants (BC and NOx) were obtained for all monitoring stations, except for Amsterdam, which might be attributable to UFP emissions from Schiphol airport. The temporal variation in particle number concentration correlated fairly weakly between the four cities (rs = 0.28-0.50, COD = 0.28-0.37), yet improved significantly inside individual cities (rs = 0.59-0.77). Nevertheless, considerable differences were still obtained in terms of particle numbers (20-38% for total particle numbers and up to 49% for size-resolved particle numbers), confirming the importance of local source contributions and the need for careful consideration when allocating UFP monitoring stations in heterogeneous urban environments.

  5. Ultrafine particle emissions by in-use diesel buses of various generations at low-load regimes

    NASA Astrophysics Data System (ADS)

    Tartakovsky, L.; Baibikov, V.; Comte, P.; Czerwinski, J.; Mayer, A.; Veinblat, M.; Zimmerli, Y.

    2015-04-01

    Ultrafine particles (UFP) are major contributors to air pollution due to their easy gas-like penetration into the human organism, causing adverse health effects. This study analyzes UFP emissions by buses of different technologies (from Euro II till Euro V EEV - Enhanced Environmentally-friendly Vehicle) at low-load regimes. Additionally, the emission-reduction potential of retrofitting with a diesel particle filter (DPF) is demonstrated. A comparison of the measured, engine-out, particle number concentrations (PNC) for buses of different technological generations shows that no substantial reduction of engine-out emissions at low-load operating modes is observed for newer bus generations. Retrofitting the in-use urban and interurban buses of Euro II till Euro IV technologies by the VERT-certified DPF confirmed its high efficiency in reduction of UFP emissions. Particle-count filtration efficiency values of the retrofit DPF were found to be extremely high - greater than 99.8%, similar to that of the OEM filter in the Euro V bus.

  6. Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house.

    PubMed

    Singer, B C; Delp, W W; Black, D R; Walker, I S

    2016-12-05

    This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM2.5 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM2.5 . Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.

  7. An electrical sensor for long-term monitoring of ultrafine particles in workplaces

    NASA Astrophysics Data System (ADS)

    Lanki, Timo; Tikkanen, Juha; Janka, Kauko; Taimisto, Pekka; Lehtimäki, Matti

    2011-07-01

    Pegasor Oy Ltd. (Finland) has developed a diffusion charging measurement device that enables continuous monitoring of fine particle concentration at a low initial and lifecycle cost. The innovation, for which an international process and apparatus patent has been applied for, opens doors for monitoring nanoparticle concentrations in workplaces. The Pegasor Particle Sensor (PPS) operates by electrostatically charging particles passing through the sensor and then measuring the current caused by the charged particles as they leave the sensor. The particles never touch the sensor and so never accumulate on its surfaces or need to be cleaned off. The sensor uses an ejector pump to draw a constant sample flow into the sensing area where it is mixed with the clean, charged pump flow air (provided by an external source). The sample flow containing charged particles passes through the sensor. The current generated by the charge leaving the detection volume is measured and related to the particle surface area. This system is extremely simple and reliable - no contact, no moving parts, and all critical parts of the sensor are constantly cleaned by a stream of fresh, filtered air. Due to the ejector pump, the sample flow, and respectively the sensor response is independent of the flow and pressure conditions around the sampling inlet. Tests with the Pegasor Particle Sensor have been conducted in a laboratory, and at a workplace producing nanoparticles for glass coatings. A new measurement protocol has been designed to ensure that process workers are not exposed to unusually high nanoparticle concentrations at any time during their working day. One sensor is placed inside the process line, and a light alarm system indicates the worker not to open any protective shielding or ventilation systems before concentration inside has reached background levels. The benefits of PPS in industrial hygiene are that the same monitoring technology can be used at the source as well as at the

  8. A PEMS study of the emissions of gaseous pollutants and ultrafine particles from gasoline- and diesel-fueled vehicles

    NASA Astrophysics Data System (ADS)

    Huang, Cheng; Lou, Diming; Hu, Zhiyuan; Feng, Qian; Chen, Yiran; Chen, Changhong; Tan, Piqiang; Yao, Di

    2013-10-01

    On-road emission measurements of gasoline- and diesel-fueled vehicles were conducted by a portable emission measurement system (PEMS) in Shanghai, China. Horiba OBS 2200 and TSI EEPS 3090 were employed to detect gaseous and ultrafine particle emissions during the tests. The driving-based emission factors of gaseous pollutants and particle mass and number were obtained on various road types. The average NOx emission factors of the diesel bus, diesel car, and gasoline car were 8.86, 0.68, and 0.17 g km-1, all of which were in excess of their emission limits. The particle number emission factors were 7.06 × 1014, 6.08 × 1014, and 1.57 × 1014 km-1, generally higher than the results for similar vehicle types reported in the previous studies. The size distributions of the particles emitted from the diesel vehicles were mainly concentrated in the accumulation mode, while those emitted from the gasoline car were mainly distributed in the nucleation mode. Both gaseous and particle emission rates exhibit significant correlations with the change in vehicle speed and power demand. The lowest emission rates for each vehicle type were produced during idling. The highest emission rates for each vehicle type were generally found in high-VSP bins. The particle number emission rates of the gasoline car show the strongest growth trend with increasing VSP and speed. The particle number emission for the gasoline car increased by 3 orders of magnitude from idling to the highest VSP and driving speed conditions. High engine power caused by aggressive driving or heavy loads is the main contributor to high emissions for these vehicles in real-world situations.

  9. Occupational Exposures and Chronic Kidney Disease: Possible associations with endotoxin and ultrafine particles

    PubMed Central

    Sponholtz, Todd R.; Sandler, Dale P.; Parks, Christine G.; Applebaum, Katie M.

    2015-01-01

    Background Chronic kidney disease (CKD) carries a high public health burden yet there is limited research on occupational factors, which are examined in this retrospective case-control study. Methods Newly diagnosed cases of CKD (n=547) and controls (n=508) from North Carolina provided detailed work histories in telephone interviews. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results There was heterogeneity in the association of CKD and agricultural work, with crop production associated with increased risk and work with livestock associated with decreased risk. Work with cutting/cooling/lubricating oils was associated with a reduced risk. CKD risk was increased for working in dusty conditions. Conclusions CKD risk was reduced in subjects with occupational exposures previously reported to involve endotoxin exposure. Further, exposure to dusty conditions was consistently associated with increased risk of glomerulonephritis across industry, suggesting that research on CKD and ultrafine particulates is needed. PMID:26572099

  10. Comparative studies on exenatide-loaded poly (D,L-lactic-co-glycolic acid) microparticles prepared by a novel ultra-fine particle processing system and spray drying.

    PubMed

    Zhu, Chune; Huang, Ying; Zhang, Xiaoying; Mei, Liling; Pan, Xin; Li, Ge; Wu, Chuanbin

    2015-08-01

    The purpose of this study was to compare the properties of exenatide-loaded poly (D,L-lactic-co-glycolic acid) microparticles (Ex-PLGA-MPs) prepared by a novel ultra-fine particle processing system (UPPS) and spray drying. UPPS is a proprietary technology developed by our group based on the disk rotation principle. Characteristics of the MPs including morphology, particle size distribution, drug content, encapsulation efficiency and in vitro release were comparatively studied. Cytotoxicity of the MPs was examined on A549 cells and the pharmacodynamics was investigated in vivo in type 2 diabetes Sprague-Dawley (SD) rats. Ex-PLGA-MPs prepared by UPPS showed larger particle size, denser surface, greater encapsulation efficiency, less initial burst release, and stable sustained release for more than one month in vitro as compared with the spray drying MPs. Meanwhile, the UPPS MPs effectively controlled the body growth rate and blood glucose in diabetes rats for at least three weeks after a single injection, while the spray drying MPs showed effective control period of about two weeks. UPPS technology was demonstrated to manufacture Ex-PLGA-MPs as a potential sustained release protein/polypeptide delivery system, which is an alternative method for the most commonly used spray drying. This comparative research provides a new guidance for microparticle preparation technology.

  11. Contribution of various microenvironments to the daily personal exposure to ultrafine particles: Personal monitoring coupled with GPS tracking

    NASA Astrophysics Data System (ADS)

    Bekö, Gabriel; Kjeldsen, Birthe Uldahl; Olsen, Yulia; Schipperijn, Jasper; Wierzbicka, Aneta; Karottki, Dorina Gabriela; Toftum, Jørn; Loft, Steffen; Clausen, Geo

    2015-06-01

    Exposure to ultrafine particles (UFP) may have adverse health effects. Central monitoring stations do not represent the personal exposure to UFP accurately. Few studies have previously focused on personal exposure to UFP. Sixty non-smoking residents living in Copenhagen, Denmark were asked to carry a backpack equipped with a portable monitor, continuously recording particle number concentrations (PN), in order to measure the real-time individual exposure over a period of ˜48 h. A GPS logger was carried along with the particle monitor and allowed us to estimate the contribution of UFP exposure occurring in various microenvironments (residence, during active and passive transport, other indoor and outdoor environments) to the total daily exposure. On average, the fractional contribution of each microenvironment to the daily integrated personal exposure roughly corresponded to the fractions of the day the subjects spent in each microenvironment. The home environment accounted for 50% of the daily personal exposure. Indoor environments other than home or vehicles contributed with ˜40%. The highest median UFP concentration was obtained during passive transport (vehicles). However, being in transit or outdoors contributed 5% or less to the daily exposure. Additionally, the subjects recorded in a diary the periods when they were at home. With this approach, 66% of the total daily exposure was attributable to the home environment. The subjects spent 28% more time at home according to the diary, compared to the GPS. These results may indicate limitations of using diaries, but also possible inaccuracy and miss-classification in the GPS data.

  12. Emissions of Ultrafine Particles and Volatile Organic Compounds from Commercially Available Desktop Three-Dimensional Printers with Multiple Filaments.

    PubMed

    Azimi, Parham; Zhao, Dan; Pouzet, Claire; Crain, Neil E; Stephens, Brent

    2016-02-02

    Previous research has shown that desktop 3D printers can emit large numbers of ultrafine particles (UFPs, particles less than 100 nm) and some hazardous volatile organic compounds (VOCs) during printing, although very few filament and 3D printer combinations have been tested to date. Here we quantify emissions of UFPs and speciated VOCs from five commercially available filament extrusion desktop 3D printers utilizing up to nine different filaments by controlled experiments in a test chamber. Median estimates of time-varying UFP emission rates ranged from ∼10(8) to ∼10(11) min(-1) across all tested combinations, varying primarily by filament material and, to a lesser extent, bed temperature. The individual VOCs emitted in the largest quantities included caprolactam from nylon-based and imitation wood and brick filaments (ranging from ∼2 to ∼180 μg/min), styrene from acrylonitrile butadiene styrene (ABS) and high-impact polystyrene (HIPS) filaments (ranging from ∼10 to ∼110 μg/min), and lactide from polylactic acid (PLA) filaments (ranging from ∼4 to ∼5 μg/min). Results from a screening analysis of potential exposure to these products in a typical small office environment suggest caution should be used when operating many of the printer and filament combinations in poorly ventilated spaces or without the aid of combined gas and particle filtration systems.

  13. Characterizing ultrafine particle growth at a pine forest site influenced by anthropogenic pollution during BEACHON-RoMBAS-2011

    NASA Astrophysics Data System (ADS)

    Cui, Y.; Hodzic, A.; Smith, J. N.; Ortega, J. V.; de Foy, B.

    2013-12-01

    Representing the formation and growth of ultrafine particles in chemistry and climate models is challenging due to the complexity of processes involved, which leads to uncertainties in aerosol size distributions and their effects on Cloud Condensation Nuclei (CCN). The Rocky Mountain Biogenic Aerosol Study (RoMBAS) was an intensive measurement campaign as part of the broader BEACHON (Bio-hydro-atmosphere interactions of Energy Aerosols, Carbon, H2O, Organics and Nitrogen) project. This took place during July - August 2011 at the Manitou Experimental Forest Observatory. The location is situated in the rural-urban interface along the Colorado Front Range and allows us to study the effects of aerosol formation and other atmospheric chemistry phenomenon in a forested region with periodic urban influences. Surface measurements of gases, aerosols and meteorological parameters from this campaign were used to examine the formation and growth processes leading to observed Aiken-mode Particle burst Events (APEs), and to quantify their effects on aerosol properties and cloud condensation nuclei CCN concentrations. Results suggest that APEs were observed at the forest site in the early afternoon associated with the arrival of anthropogenic plumes from Denver and Colorado Springs. Mean number concentrations of ultrafine particles (4-30nm) typically exceeded 5000 cm-3 during APEs and these elevated concentrations were correlated with elevated SO2. The Weather Research and Forecasting model with on-line Chemistry (WRF-Chem) was used to model APEs during BEACHON-RoMBAS. The model was updated to include an activation nucleation (AN) scheme with an empirical representation of aerosol nucleation rate, and subsequent growth due to the condensation of organic and inorganic vapors. Comparisons with ground measurements show that the updated model reasonably captures aerosol number concentrations and size distribution during APEs, as well as CN and CCN concentrations. Model results

  14. Intra-urban variation of ultrafine particles as evaluated by process related land use and pollutant driven regression modelling.

    PubMed

    Ghassoun, Yahya; Ruths, Matthias; Löwner, Marc-Oliver; Weber, Stephan

    2015-12-01

    The microscale intra-urban variation of ultrafine particle concentrations (UFP, diameter Dp<100 nm) and particle number size distributions was studied by two statistical regression approaches. The models were applied to a 1 km2 study area in Braunschweig, Germany. A land use regression model (LUR) using different urban morphology parameters as input is compared to a multiple regression type model driven by pollutant and meteorological parameters (PDR). While the LUR model was trained with UFP concentration the PDR model was trained with measured particle number size distribution data. The UFP concentration was then calculated from the modelled size distributions. Both statistical approaches include explanatory variables that try to address the 'process chain' of particle emission, dilution and deposition. LUR explained 74% and 85% of the variance of UFP for the full data set with a root mean square error (RMSE) of 668 cm(-3) and 1639 cm(-3) in summer and winter, respectively. PDR explained 56% and 74% of the variance with RMSE of 4066 cm(-3) and 6030 cm(-3) in summer and winter, respectively. Both models are capable to depict the spatial variation of UFP across the study area and in different outdoor microenvironments. The deviation from measured UFP concentrations is smaller in the LUR model than in PDR. The PDR model is well suited to predict urban particle number size distributions from the explanatory variables (total particle number concentration, black carbon and wind speed). The urban morphology parameters in the LUR model are able to resolve size dependent concentration variations but not as adequately as PDR.

  15. Are Ambient Ultrafine, Accumulation Mode, and Fine Particles Associated with Adverse Cardiac Responses in Patients Undergoing Cardiac Rehabilitation?

    PubMed Central

    Zareba, Wojciech; Beckett, William; Hopke, Philip K; Oakes, David; Frampton, Mark W; Bisognano, John; Chalupa, David; Bausch, Jan; O’Shea, Karen; Wang, Yungang; Utell, Mark J

    2012-01-01

    Background: Mechanisms underlying previously reported air pollution and cardiovascular (CV) morbidity associations remain poorly understood. Objectives: We examined associations between markers of pathways thought to underlie these air pollution and CV associations and ambient particle concentrations in postinfarction patients. Methods: We studied 76 patients, from June 2006 to November 2009, who participated in a 10-week cardiac rehabilitation program following a recent (within 3 months) myocardial infarction or unstable angina. Ambient ultrafine particle (UFP; 10–100 nm), accumulation mode particle (AMP; 100–500 nm), and fine particle concentrations (PM2.5; ≤ 2.5 μm in aerodynamic diameter) were monitored continuously. Continuous Holter electrocardiogram (ECG) recordings were made before and during supervised, graded, twice weekly, exercise sessions. A venous blood sample was collected and blood pressure was measured before sessions. Results: Using mixed effects models, we observed adverse changes in rMSSD [square root of the mean of the sum of the squared differences between adjacent normal-to-normal (NN) intervals], SDNN (standard deviation of all NN beat intervals), TpTe (time from peak to end of T-wave), heart rate turbulence, systolic and diastolic blood pressures, C-reactive protein, and fibrinogen associated with interquartile range increases in UFP, AMP, and PM2.5 at 1 or more lag times within the previous 5 days. Exposures were not associated with MeanNN, heart-rate–corrected QT interval duration (QTc), deceleration capacity, and white blood cell count was not associated with UFP, AMP, and PM2.5 at any lag time. Conclusions: In cardiac rehabilitation patients, particles were associated with subclinical decreases in parasympathetic modulation, prolongation of late repolarization duration, increased blood pressure, and systemic inflammation. It is possible that such changes could increase the risk of CV events in this susceptible population. PMID

  16. Modification of laminar flow ultrafine condensation particle counters for the enhanced detection of 1 nm condensation nuclei

    SciTech Connect

    Kuang, C.; Chen, M.; McMurry, P. H.; Wang, J.

    2011-10-01

    This paper describes simple modifications to thermally diffusive laminar flow ultrafine condensation particle counters (UCPCs) that allow detection of {approx}1 nm condensation nuclei with much higher efficiencies than have been previously reported. These nondestructive modifications were applied to a commercial butanol based UCPC (TSI 3025A) and to a diethylene glycol-based UCPC (UMN DEG-UCPC). Size and charge dependent detection efficiencies using the modified UCPCs (BNL 3025A and BNL DEGUCPC) were measured with high resolution mobility classified aerosols composed of NaCl, W, molecular ion standards of tetraalkyl ammonium bromide, and neutralizer-generated ions. With negatively charged NaCl aerosol, the BNL 3025A and BNL DEGUCPC achieved detection efficiencies of 37% (90x increase over TSI 3025A) at 1.68 nm mobility diameter (1.39 nm geometric diameter) and 23% (8x increase over UMN DEG-UCPC) at 1.19 nm mobility diameter (0.89 nm geometric diameter), respectively. Operating conditions for both UCPCs were identified that allowed negatively charged NaCl and W particles, but not negative ions of exactly the same mobility size, to be efficiently detected. This serendipitous material dependence, which is not fundamentally understood, suggests that vapor condensation might sometimes allow for the discrimination between air 'ions' and charged 'particles.' As a detector in a scanning mobility particle spectrometer (SMPS), a UCPC with this strong material dependence would allow for more accurate measurements of sub-2 nm aerosol size distributions due to the reduced interference from neutralizer-generated ions and atmospheric ions, and provide increased sensitivity for the determination of nucleation rates and initial particle growth rates.

  17. Lead and cadmium phytoavailability and human bioaccessibility for vegetables exposed to soil or atmospheric pollution by process ultrafine particles.

    PubMed

    Xiong, Tiantian; Leveque, Thibault; Shahid, Muhammad; Foucault, Yann; Mombo, Stéphane; Dumat, Camille

    2014-09-01

    When plants are exposed to airborne particles, they can accumulate metals in their edible portions through root or foliar transfer. There is a lack of knowledge on the influence of plant exposure conditions on human bioaccessibility of metals, which is of particular concern with the increase in urban gardening activities. Lettuce, radish, and parsley were exposed to metal-rich ultrafine particles from a recycling factory via field atmospheric fallouts or polluted soil. Total lead (Pb) and cadmium (Cd) concentrations in of the edible plant parts and their human bioaccessibility were measured, and Pb translocation through the plants was studied using Pb isotopic analysis. The Pb and Cd bioaccessibility measured for consumed parts of the different polluted plants was significantly higher for root exposure (70% for Pb and 89% for Cd in lettuce) in comparison to foliar exposure (40% for Pb and 69% for Cd in lettuce). The difference in metal bioaccessibility could be linked to the metal compartmentalization and speciation changes in relation to exposure conditions. Metal nature strongly influences the measured bioaccessibility: Cd presents higher bioaccessibility in comparison to Pb. In the case of foliar exposure, a significant translocation of Pb from leaves toward the roots was observed. To conclude, the type of pollutant and the method of exposure significantly influences the phytoavailability and human bioaccessibility of metals, especially in relation to the contrasting phenomena involved in the rhizosphere and phyllosphere. The conditions of plant exposure must therefore be taken into account for environmental and health risk assessment.

  18. Preparation and in vitro evaluation of silk fibroin microspheres produced by a novel ultra-fine particle processing system.

    PubMed

    Wen, Xinguo; Peng, Xinsheng; Fu, Han; Dong, Yixuan; Han, Ke; Su, Jianfen; Wang, Zhouhua; Wang, Rongchang; Pan, Xin; Huang, Lin; Wu, Chuanbin

    2011-09-15

    The objective of this study was to prepare silk fibroin SF microspheres containing the enhanced green fluorescent protein (EGFP) by using a novel ultra-fine particle processing system (UPPS) and to evaluate the microspheres as possible carriers for long-term delivery of sensitive biologicals. The drug content, encapsulation efficiency, and in vitro release were evaluated by Microplate Absorbance Reader. The particle size distribution and morphology of the microspheres were analyzed by Malvern Master Sizer 2000 and scanning electron microscopy. The distribution of EGFP and the interactions between SF and EGFP were investigated by Confocal Laser Scanning Microscopy, FTIP, Raman and NMR spectroscopy. The results showed that spherical microspheres with narrow size distribution, glossy and dense surface were successfully manufactured by using UPPS technology and over 95% of EGFP encapsulation efficiency and uniform drug distribution in the microspheres were achieved. Furthermore, a burst free and sustained release of encapsulated EGFP for a period of 50 days in deionized water was obtained. In conclusion, the novel UPPS technology could be used to manufacture SF matrix microspheres as a potential long-term protein delivery system to improve patient compliance and convenience.

  19. Crucial Role for Outdoor Chemistry in Ultrafine Particle Formation in Modern Office Buildings.

    PubMed

    Carslaw, Nicola; Ashmore, Mike; Terry, Andrew C; Carslaw, David C

    2015-09-15

    In the developed world, we spend most of our time indoors, where we receive the majority of our exposure to air pollution. This paper reports model simulations of PM2.5 and ozone concentrations in identical landscape offices in three European cities: Athens, Helsinki, and Milan. We compare concentrations during an intense heatwave in August 2003 with a meteorologically more typical August in 2009. During the heatwave, average indoor ozone concentrations during office hours were 44, 19, and 41 ppb in Athens, Helsinki, and Milan respectively, enhanced by 7, 4, and 17 ppb respectively relative to 2009. Total predicted PM2.5 concentrations were 13.5, 3.6, and 17.2 μg m(-3) in Athens, Helsinki, and Milan respectively, enhanced by 0.5, 0.4, and 6.7 μg m(-3) respectively relative to 2009: the three cities were affected to differing extents by the heatwave. A significant portion of the indoor PM2.5 derived from gas-phase chemistry outdoors, producing 2.5, 0.8, and 4.8 μg m(-3) of the total concentrations in Athens, Helsinki, and Milan, respectively. Despite filtering office inlet supplies to remove outdoor particles, gas-phase precursors for particles can still enter offices, where conditions are ripe for new particles to form, particularly where biogenic emissions are important outdoors. This result has important implications for indoor air quality, particularly given the current trend for green walls on buildings, which will provide a potential source of biogenic emissions near to air inlet systems.

  20. Ultrafine PM emissions from natural gas, oxidation-catalyst diesel, and particle-trap diesel heavy-duty transit buses.

    PubMed

    Holmén, Britt A; Ayala, Alberto

    2002-12-01

    baseline concentrations when driving under load. The results do not support use of CVS dilution methodology for ultrafine particle sampling, and, despite attention to collection of tunnel blanks in this study, results indicate that a protocol needs to be determined and prescribed for taking into account tunnel blank "emissions" to obtain meaningful comparisons between different technologies. Of critical importance is determining how temperature differences between tunnel blank and test cycle sampling compare in terms of background particle numbers. Total particle number concentrations for the minidiluter sampling point were not significantly different for the two alternative technologies when considering all the steady-cycle data collected. Concentrations ranged from 0.8 to 3 x 10(6) for the baseline bus operating on ultralow sulfur fuel, from 0.5 to 9 x 10(4) for the diesel bus equipped with the CRT filter, and from 1 to 8 x 10(4) particles/cc for the CNG bus.

  1. Development of the electroacoustic dewatering (EAD) process for fine/ultrafine coal

    SciTech Connect

    Chauhan, S.P.; Kim, B.C.; Menton, R.; Senapati, N.; Criner, C.L.; Jirjis, B.; Muralidhara, H.S.; Chou, Y.L.; Wu, H.; Hsieh, P. ); Johnson, H.R.; Eason, R. ); Chiang, S.M.; Cheng, Y.S. ); Kehoe, D. )

    1991-10-31

    Battelle (Columbus, Ohio) undertook development of its electro-acoustic (EAD) process to demonstrate its commercial potential for continuous dewatering of fine and ultrafine coals. The pilot plant and laboratory results, provided in this report, show that a commercial-size EAD machine is expected to economically achieve the dewatering targets for {minus}100 mesh and {minus}325 mesh coals. The EAD process utilizes a synergistic combination of electric and acoustic (e.g., ultrasonic) fields in conjunction with conventional mechanical processes, such as belt presses, screw presses, plate and frame filter presses, and vacuum filters. The application of EAD is typically most beneficial after a filter cake is formed utilizing conventional mechanical filtration. (VC)

  2. Development of the electroacoustic dewatering (EAD) process for fine/ultrafine coal. Final report

    SciTech Connect

    Chauhan, S.P.; Kim, B.C.; Menton, R.; Senapati, N.; Criner, C.L.; Jirjis, B.; Muralidhara, H.S.; Chou, Y.L.; Wu, H.; Hsieh, P.; Johnson, H.R.; Eason, R.; Chiang, S.M.; Cheng, Y.S.; Kehoe, D.

    1991-10-31

    Battelle (Columbus, Ohio) undertook development of its electro-acoustic (EAD) process to demonstrate its commercial potential for continuous dewatering of fine and ultrafine coals. The pilot plant and laboratory results, provided in this report, show that a commercial-size EAD machine is expected to economically achieve the dewatering targets for {minus}100 mesh and {minus}325 mesh coals. The EAD process utilizes a synergistic combination of electric and acoustic (e.g., ultrasonic) fields in conjunction with conventional mechanical processes, such as belt presses, screw presses, plate and frame filter presses, and vacuum filters. The application of EAD is typically most beneficial after a filter cake is formed utilizing conventional mechanical filtration. (VC)

  3. Complex nanominerals and ultrafine particles assemblages in phosphogypsum of the fertilizer industry and implications on human exposure.

    PubMed

    Silva, Luis F O; Hower, James C; Izquierdo, Maria; Querol, Xavier

    2010-10-01

    Phosphogypsum (CaSO(4).2H(2)O), a by-product of phosphate-rock processing, contains high amounts of impurities such P(2)O(5), F, radioactive elements, organic substances, secondary nanominerals, and ultrafine particles (UFP) enriched in metals and metalloids. In this study, we examine phosphogypsum (PG) collected from abandoned fertilizer industry facility in south Brazil (Santa Catarina state). The fragile nature of nanominerals and UFP assemblages from fertilizer industry systems required novel techniques and experimental approaches. The investigation of the geochemistry of complex nanominerals and UFP assemblages was a prerequisite to accurately assess the environmental and human health risks of contaminants and cost-effective chemical and biogeological remediation strategies. Particular emphasis was placed on the study and characterization of the complex mixed nanominerals and UFP containing potentially toxic elements. Nanometer-sized phases in PG were characterized using energy-dispersive X-ray spectrometer (EDS), field-emission scanning electron microscope (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM) images. The chemical composition and possible correlations with morphology of nanominerals and UFP, as well as aspects of nanominerals and UFP, are discussed in the context of human health exposure, as well as in relation to management of the nanominerals and UFP in PG environments.

  4. Ultrafine particles and black carbon personal exposures in asthmatic and non-asthmatic children at school-age.

    PubMed

    Pañella, Pau; Casas, Maribel; Donaire-Gonzalez, David; Garcia-Esteban, Raquel; Robinson, Oliver; Valentín, Antònia; Gulliver, John; Momas, Isabelle; Nieuwenhuijsen, Mark; Vrijheid, Martine; Sunyer, Jordi

    2017-03-20

    Traffic-related air pollution (TRAP) exposure during childhood is associated with asthma; however, the contribution of the different TRAP pollutants in each microenvironment (home, school, transportation, others) in asthmatic and non-asthmatic children is unknown. Daily (24 h) personal black carbon (BC), ultrafine particles (UFP), and alveolar lung deposited surface area (LDSA) individual exposure measurements were obtained from 100 children (29 past and 21 current asthmatics, 50 non-asthmatics) aged 9±0.7 years from the INMA-Sabadell cohort (Catalonia, Spain). Time spent in each microenvironment was derived by the geolocation provided by the smartphone and a new spatiotemporal map-matching algorithm. Asthmatics and non-asthmatics spent the same amount of time at home (60% and 61%, respectively), at school (20%, 23%), on transportation (8%, 7%), and in other microenvironments (7%, 5%). The highest concentrations of all TRAPs were attributed to transportation. No differences in TRAP concentrations were found overall or by type of microenvironment between asthmatics and non-asthmatics, nor when considering past and current asthmatics, separately. In conclusion, asthmatic and non-asthmatic children had a similar time activity pattern and similar average exposures to BC, UFP and LDSA concentrations. This suggests that interventions should be tailored to general population, rather than to subgroups defined by disease. This article is protected by copyright. All rights reserved.

  5. Personal measurement of exposure to black carbon and ultrafine particles in schoolchildren from PARIS cohort (Paris, France).

    PubMed

    Paunescu, A-C; Attoui, M; Bouallala, S; Sunyer, J; Momas, I

    2016-11-22

    This study aimed to measure in French children personal exposure concentrations of black carbon (BC) and ultrafine particles (UFP) and to quantify the contribution of different microenvironments (home, school, places of extracurricular activities, transport) to their total exposure. It was conducted on 96 9-year-old children from the PARIS birth cohort. BC and UFP were continuously measured by portable devices (microAeth(®) AE51 and DiSCmini(®) ) for a minimum of 24 hours, while participating families simultaneously filled in a space-time-activities-budget questionnaire. BC exposure concentration was higher during trips (principally metro/train and bus), while UFP exposure concentration was higher during indoor activities (mainly eating at restaurants) and in trips. The most important UFP peaks were measured at home, especially during cooking. Home and school together accounted for much of the total exposure, 83.8% for BC and 85.3% for UFP. The contribution of transport to total exposure was 12.4% for BC and 9.7% for UFP, while extracurricular activities were responsible for 3.8% and 5% of the total exposure to BC and UFP, respectively.

  6. Ambient ultrafine particles provide a strong adjuvant effect in the secondary immune response: implication for traffic-related asthma flares.

    PubMed

    Li, Ning; Harkema, Jack R; Lewandowski, Ryan P; Wang, Meiying; Bramble, Lori A; Gookin, Glenn R; Ning, Zhi; Kleinman, Michael T; Sioutas, Constantinos; Nel, Andre E

    2010-09-01

    We have previously demonstrated that intranasal administration of ambient ultrafine particles (UFP) acts as an adjuvant for primary allergic sensitization to ovalbumin (OVA) in Balb/c mice. It is important to find out whether inhaled UFP exert the same effect on the secondary immune response as a way of explaining asthma flares in already-sensitized individuals due to traffic exposure near a freeway. The objective of this study is to determine whether inhalation exposure to ambient UFP near an urban freeway could enhance the secondary immune response to OVA in already-sensitized mice. Prior OVA-sensitized animals were exposed to concentrated ambient UFP at the time of secondary OVA challenge in our mobile animal laboratory in Los Angeles. OVA-specific antibody production, airway morphometry, allergic airway inflammation, cytokine gene expression, and oxidative stress marker were assessed. As few as five ambient UFP exposures were sufficient to promote the OVA recall immune response, including generating allergic airway inflammation in smaller and more distal airways compared with the adjuvant effect of intranasally instilled UFP on the primary immune response. The secondary immune response was characterized by the T helper 2 and IL-17 cytokine gene expression in the lung. In summary, our results demonstrated that inhalation of prooxidative ambient UFP could effectively boost the secondary immune response to an experimental allergen, indicating that vehicular traffic exposure could exacerbate allergic inflammation in already-sensitized subjects.

  7. Reduction of exposure to ultrafine particles by kitchen exhaust hoods: the effects of exhaust flow rates, particle size, and burner position.

    PubMed

    Rim, Donghyun; Wallace, Lance; Nabinger, Steven; Persily, Andrew

    2012-08-15

    Cooking stoves, both gas and electric, are one of the strongest and most common sources of ultrafine particles (UFP) in homes. UFP have been shown to be associated with adverse health effects such as DNA damage and respiratory and cardiovascular diseases. This study investigates the effectiveness of kitchen exhaust hoods in reducing indoor levels of UFP emitted from a gas stove and oven. Measurements in an unoccupied manufactured house monitored size-resolved UFP (2 nm to 100 nm) concentrations from the gas stove and oven while varying range hood flow rate and burner position. The air change rate in the building was measured continuously based on the decay of a tracer gas (sulfur hexafluoride, SF(6)). The results show that range hood flow rate and burner position (front vs. rear) can have strong effects on the reduction of indoor levels of UFP released from the stove and oven, subsequently reducing occupant exposure to UFP. Higher range hood flow rates are generally more effective for UFP reduction, though the reduction varies with particle diameter. The influence of the range hood exhaust is larger for the back burner than for the front burner. The number-weighted particle reductions for range hood flow rates varying between 100 m(3)/h and 680 m(3)/h range from 31% to 94% for the front burner, from 54% to 98% for the back burner, and from 39% to 96% for the oven.

  8. Evaluation of the Quick Urban and Industrial Complex (QUIC) Modeling System to Predict Ultrafine Particle Levels in an Urban Neighborhood near a Highway

    NASA Astrophysics Data System (ADS)

    St. Vincent, A.; Milando, C.; Zhu, S.; Zamore, W.; Brugge, D.; Durant, J.

    2010-12-01

    Exposure to vehicle-generated ultrafine particles (<100 nm; UFP) has been linked to cardiovascular and pulmonary diseases in people living near highways. Due to the high degree of temporal and spatial variation of UFP near highways, models are needed to help predict UFP exposures in near-highway neighborhoods. The goals of this work were to evaluate the ability of QUIC, a random-walk dispersion model, to predict near-highway UFP in an urban neighborhood (<1 km2) for different wind conditions and land-surface detail. QUIC was chosen because it is able to capture a wide variety of land-surface features and has relatively small computational requirements. QUIC models were developed with and without individually-resolved buildings for a neighborhood near Interstate 93 in Somerville (MA, USA), and tested using wind conditions characteristic of the area. Model results were then compared to field data collected with a mobile air pollution monitoring laboratory. Generally good agreement was observed between the model results and field data for winds parallel and perpendicular to the highway. In addition, models that treated neighborhood blocks (i.e., collections of houses surrounded by four intersecting streets) as porous structures through which attenuated wind and UFP could pass performed better than models containing non-porous solid blocks or individual buildings. These results will help inform the development of a predictive UFP model that will be used as part of a cardiovascular health study being conducted in several neighborhoods near I-93 in Somerville.

  9. Indoor/outdoor relationships and mass closure of quasi-ultrafine, accumulation and coarse particles in Barcelona schools

    NASA Astrophysics Data System (ADS)

    Viana, M.; Rivas, I.; Querol, X.; Alastuey, A.; Sunyer, J.; Álvarez-Pedrerol, M.; Bouso, L.; Sioutas, C.

    2014-05-01

    The mass concentration, chemical composition and sources of quasi-ultrafine (quasi-UFP, PM0.25), accumulation (PM0.25-2.5) and coarse mode (PM2.5-10) particles were determined in indoor and outdoor air at 39 schools in Barcelona (Spain). Quasi-UFP mass concentrations measured (25.6 μg m-3 outdoors, 23.4 μg m-3 indoors) are significantly higher than those reported in other studies, and characterised by higher carbonaceous and mineral matter contents and a lower proportion of secondary inorganic ions. Results suggest that quasi-UFPs in Barcelona are affected by local sources in the schools, mainly human activity (e.g. organic material from textiles, etc., contributing 23-46% to total quasi-UFP mass) and playgrounds (in the form of mineral matter, contributing about 9% to the quasi-UFP mass). The particle size distribution patterns of toxicologically relevant metals and major aerosol components was characterised, displaying two modes for most elements and components, and one mode for inorganic salts (ammonium nitrate and sulfate) and elemental carbon (EC). Regarding metals, Ni and Cr were partitioned mainly in quasi-UFPs and could thus be of interest for epidemiological studies, given their high redox properties. Exposure of children to quasi-UFP mass and chemical species was assessed by comparing the concentrations measured at urban background and traffic areas schools. Finally, three main indoor sources across all size fractions were identified by assessing indoor / outdoor ratios (I / O) of PM species used as their tracers: human activity (organic material), cleaning products, paints and plastics (Cl- source), and a metallic mixed source (comprising combinations of Cu, Zn, Co, Cd, Pb, As, V and Cr). Our results support the need to enforce targeted legislation to determine a minimum "safe" distance between major roads and newly built schools to reduce exposure to traffic-derived metals in quasi-UFPs.

  10. Using advanced dispersion models and mobile monitoring to characterize spatial patterns of ultrafine particles in an urban area

    NASA Astrophysics Data System (ADS)

    Zwack, Leonard M.; Hanna, Steven R.; Spengler, John D.; Levy, Jonathan I.

    2011-09-01

    In urban settings with elevated bridges, buildings, and other complex terrain, the relationship between traffic and air pollution can be highly variable and difficult to accurately characterize. Atmospheric dispersion models are often used in this context, but incorporating background concentrations and characterizing emissions at high spatiotemporal resolution is challenging, especially for ultrafine particles (UFPs). Ambient pollutant monitoring can characterize this relationship, especially when using continuous real-time monitoring. However, it is challenging to quantify local source contributions over background or to characterize spatial patterns across a neighborhood. The goal of this study is to evaluate contributions of traffic to neighborhood-scale air pollution using a combination of regression models derived from mobile UFP monitoring observations collected in Brooklyn, NY and outputs from the Quick Urban & Industrial Complex (QUIC) model. QUIC is a dispersion model that can explicitly take into account the three-dimensional shapes of buildings. The monitoring-based regression model characterized concentration gradients from a major elevated roadway, controlling for real-time traffic volume, meteorological variables, and other local sources. QUIC was applied to simulate dispersion from this same major roadway. The relative concentration decreases with distance from the roadway estimated by the monitoring-based regression model after removal of background and by QUIC were similar. Horizontal contour plots with both models demonstrated non-uniform patterns related to building configuration and source heights. We used the best-fit relationship between the monitoring-based regression model after removal of background and the QUIC outputs ( R2 = 0.80) to estimate a UFP emissions factor of 5.7 × 10 14 particles/vehicle-km, which was relatively consistent across key model assumptions. Our joint applications of novel techniques for analyzing mobile monitoring

  11. Pulmonary delivery of an ultra-fine oxytocin dry powder formulation: potential for treatment of postpartum haemorrhage in developing countries.

    PubMed

    Prankerd, Richard J; Nguyen, Tri-Hung; Ibrahim, Jibriil P; Bischof, Robert J; Nassta, Gemma C; Olerile, Livesey D; Russell, Adrian S; Meiser, Felix; Parkington, Helena C; Coleman, Harold A; Morton, David A V; McIntosh, Michelle P

    2013-01-01

    Oxytocin is recommended by the World Health Organisation as the most effective uterotonic for the prevention and treatment of postpartum haemorrhage. The requirement for parenteral administration by trained healthcare providers and the need for the drug solution to be maintained under cold-chain storage limit the use of oxytocin in the developing world. In this study, a spray-dried ultrafine formulation of oxytocin was developed with an optimal particle size diameter (1-5 µm) to facilitate aerosolised delivery via the lungs. A powder formulation of oxytocin, using mannitol, glycine and leucine as carriers, was prepared with a volume-based median particle diameter of 1.9 µm. Oxytocin content in the formulation was assayed using high-performance liquid chromatography-mass spectroscopy and was found to be unchanged after spray-drying. Ex vivo contractility studies utilising human and ovine uterine tissue indicated no difference in the bioactivity of oxytocin before and after spray-drying. Uterine electromyographic (EMG) activity in postpartum ewes following pulmonary (in vivo) administration of oxytocin closely mimicked that observed immediately postpartum (0-12 h following normal vaginal delivery of the lamb). In comparison to the intramuscular injection, pulmonary administration of an oxytocin dry powder formulation to postpartum ewes resulted in generally similar EMG responses, however a more rapid onset of uterine EMG activity was observed following pulmonary administration (129 ± 18 s) than intramuscular injection (275 ± 22 s). This is the first study to demonstrate the potential for oxytocin to elicit uterine activity after systemic absorption as an aerosolised powder from the lungs. Aerosolised oxytocin has the potential to provide a stable and easy to administer delivery system for effective prevention and treatment of postpartum haemorrhage in resource-poor settings in the developing world.

  12. Validation and Application of the Mass Balance Model To Determine the Effectiveness of Portable Air Purifiers in Removing Ultrafine and Submicrometer Particles in an Apartment.

    PubMed

    Lee, Wan-Chen; Catalano, Paul J; Yoo, Jun Young; Park, Chan Jung; Koutrakis, Petros

    2015-08-18

    We validated the use of the mass balance model to determine the effectiveness of portable air purifiers in removing ultrafine (<0.10 μm) and submicrometer particles (0.10-0.53 μm) in an apartment. We evaluated two identical portable air purifiers, equipped with high efficiency particulate air filters, for their performance under three different air flow settings and three target air exchange rates: 0.60, 0.90, and 1.20 h(-1). We subsequently used a mixed effects model to estimate the slope between the measured and modeled effectiveness by particle size. Our study showed that effectiveness was highly particle size-dependent. For example, at the lowest target air exchange rate, it ranged from 0.33 to 0.56, 0.51 to 0.75, and 0.60 to 0.81 for the three air purifier flow settings, respectively. Our findings suggested that filtration was the dominant removal mechanism for submicrometer particles, whereas deposition could play a more important role in ultrafine particle removal. We found reasonable agreement between measured and modeled effectiveness with size-resolved slopes ranging from 1.11 ± 0.06 to 1.25 ± 0.07 (mean ± SE), except for particles <35 nm. Our study design can be applied to investigate the performances of other portable air purifiers as well as the influences of various parameters on effectiveness in different residential settings.

  13. Size controllable synthesis of ultrafine spherical gold particles and their simulation of plasmonic and SERS behaviors

    NASA Astrophysics Data System (ADS)

    Yi, Zao; Xu, Xibin; Luo, Jiangshan; Li, Xibo; Yi, Yong; Jiang, Xiaodong; Yi, Yougen; Tang, Yongjian

    2014-04-01

    A simple and reproducible way was explored to synthesize quasi-spherical gold particles with different size distributions in water by rapidly adding a mixture solution of HAuCl4, sodium citrate, and a trace amount of silver nitrate. By careful tuning of the reaction parameters, mono-disperse gold particles with the diameter of 5-220 nm can be obtained controllably. The particle size of 130 nm for the particles film showed the highest SERS activity with the 632.8 nm excitation. The theoretical calculations of the UV-vis extinction spectra can be directly compared with experiments by using the discrete-dipole approximation (DDA). Control of nanostructure shape allows optimization of plasmon resonance for molecular detection and spectroscopy.

  14. Transferability and Generalizability of Regression Models of Ultrafine Particles in Urban Neighborhoods in the Boston Area

    PubMed Central

    2015-01-01

    Land use regression (LUR) models have been used to assess air pollutant exposure, but limited evidence exists on whether location-specific LUR models are applicable to other locations (transferability) or general models are applicable to smaller areas (generalizability). We tested transferability and generalizability of spatial-temporal LUR models of hourly particle number concentration (PNC) for Boston-area (MA, U.S.A.) urban neighborhoods near Interstate 93. Four neighborhood-specific regression models and one Boston-area model were developed from mobile monitoring measurements (34–46 days/neighborhood over one year each). Transferability was tested by applying each neighborhood-specific model to the other neighborhoods; generalizability was tested by applying the Boston-area model to each neighborhood. Both the transferability and generalizability of models were tested with and without neighborhood-specific calibration. Important PNC predictors (adjusted-R2 = 0.24–0.43) included wind speed and direction, temperature, highway traffic volume, and distance from the highway edge. Direct model transferability was poor (R2 < 0.17). Locally-calibrated transferred models (R2 = 0.19–0.40) and the Boston-area model (adjusted-R2 = 0.26, range: 0.13–0.30) performed similarly to neighborhood-specific models; however, some coefficients of locally calibrated transferred models were uninterpretable. Our results show that transferability of neighborhood-specific LUR models of hourly PNC was limited, but that a general model performed acceptably in multiple areas when calibrated with local data. PMID:25867675

  15. Comparing the impact of ultrafine particles from petrodiesel and biodiesel combustion to bacterial metabolism by targeted HPLC-MS/MS metabolic profiling.

    PubMed

    Zhong, Fanyi; Xu, Mengyang; Schelli, Katie; Rutowski, Joshua; Holmén, Britt A; Zhu, Jiangjiang

    2017-04-11

    Alterations of gut bacterial metabolism play an important role in their host metabolism, and can result in diseases such as obesity and diabetes. While many factors were discovered influencing the gut bacterial metabolism, exposure to ultrafine particles (UFPs) from engine combustions were recently proposed to be a potential risk factor for the perturbation of gut bacterial metabolism, and consequentially to obesity and diabetes development. This study focused on evaluation of how UFPs from diesel engine combustions impact gut bacterial metabolism. We hypothesize that UFPs from different type of diesel (petrodiesel vs. biodiesel) will both impact bacterial metabolism, and the degree of impact is also diesel type-dependent. Targeted metabolic profiling of 221 metabolites were applied to three model gut bacteria in vitro, Streptococcus salivarius, Lactobacillus acidophilus and Lactobacillus fermentum. UFPs from two types of fuels, petrodiesel (B0) and a biodiesel blend (B20: 20% soy biodiesel/80% B0 by volume), were exposed to the bacteria and their metabolic changes were compared. For each bacterial strain, metabolites with significantly changed abundance were observed in both perturbations, and all three strains have increased number of altered metabolites detected from B20 UFPs perturbation in comparison to B0 UFPs. Multivariate statistical analysis further confirmed that the metabolic profiles were clearly different between testing groups. Metabolic pathway analyses also demonstrated several important metabolic pathways, including pathways involves amino acids biosynthesis and sugar metabolism, were significantly impacted by UFPs exposure.

  16. Application of a high-efficiency cabin air filter for simultaneous mitigation of ultrafine particle and carbon dioxide exposures inside passenger vehicles.

    PubMed

    Lee, Eon S; Zhu, Yifang

    2014-02-18

    Modern passenger vehicles are commonly equipped with cabin air filters but their filtration efficiency for ultrafine particle (UFP) is rather low. Although setting the vehicle ventilation system to recirculation (RC) mode can reduce in-cabin UFPs by ∼ 90%, passenger-exhaled carbon dioxide (CO2) can quickly accumulate inside the cabin. Using outdoor air (OA) mode instead can provide sufficient air exchange to prevent CO2 buildup, but in-cabin UFP concentrations would increase. To overcome this dilemma, we developed a simultaneous mitigation method for UFP and CO2 using high-efficiency cabin air (HECA) filtration in OA mode. Concentrations of UFP and other air pollutants were simultaneously monitored in and out of 12 different vehicles under 3 driving conditions: stationary, on local roadways, and on freeways. Under each experimental condition, data were collected with no filter, in-use original equipment manufacturer (OEM) filter, and two types of HECA filters. The HECA filters offered an average in-cabin UFP reduction of 93%, much higher than the OEM filters (∼ 50% on average). Throughout the measurements, the in-cabin CO2 concentration remained in the range of 620-930 ppm, significantly lower than the typical level of 2500-4000 ppm observed in the RC mode.

  17. Capture Efficiency of Cooking-Related Fine and Ultrafine Particles by Residential Exhaust Hoods

    SciTech Connect

    Lunden, Melissa M.; Delp, William W.

    2014-06-05

    Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80percent. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38percent for low (51?68 L s-1) and 54?72percent for high (109?138 L s-1) settings. CEs for 0.3?2.0 ?m particles during front burner stir-frying were 3?11percent on low and 16?70percent on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80percent both for burner combustion products and for cooking-related particles.

  18. Capture efficiency of cooking-related fine and ultrafine particles by residential exhaust hoods.

    PubMed

    Lunden, M M; Delp, W W; Singer, B C

    2015-02-01

    Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking-generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80%. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38% for low (51-68 l/s) and 54-72% for high (109-138 l/s) settings. CEs for 0.3-2.0 μm particles during front burner stir-frying were 3-11% on low and 16-70% on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80% both for burner combustion products and for cooking-related particles.

  19. Effects of Particle Filters and Accelerated Engine Replacement on Heavy-Duty Diesel Vehicle Emissions of Black Carbon, Nitrogen Oxides, and Ultrafine Particles

    NASA Astrophysics Data System (ADS)

    Kirchstetter, T.; Preble, C.; Dallmann, T. R.; DeMartini, S. J.; Tang, N. W.; Kreisberg, N. M.; Hering, S. V.; Harley, R. A.

    2013-12-01

    Diesel particle filters have become widely used in the United States since the introduction in 2007 of a more stringent exhaust particulate matter emission standard for new heavy-duty diesel vehicle engines. California has instituted additional regulations requiring retrofit or replacement of older in-use engines to accelerate emission reductions and air quality improvements. This presentation summarizes pollutant emission changes measured over several field campaigns at the Port of Oakland in the San Francisco Bay Area associated with diesel particulate filter use and accelerated modernization of the heavy-duty truck fleet. Pollutants in the exhaust plumes of hundreds of heavy-duty trucks en route to the Port were measured in 2009, 2010, 2011, and 2013. Ultrafine particle number, black carbon (BC), nitrogen oxides (NOx), and nitrogen dioxide (NO2) concentrations were measured at a frequency ≤ 1 Hz and normalized to measured carbon dioxide concentrations to quantify fuel-based emission factors (grams of pollutant emitted per kilogram of diesel consumed). The size distribution of particles in truck exhaust plumes was also measured at 1 Hz. In the two most recent campaigns, emissions were linked on a truck-by-truck basis to installed emission control equipment via the matching of transcribed license plates to a Port truck database. Accelerated replacement of older engines with newer engines and retrofit of trucks with diesel particle filters reduced fleet-average emissions of BC and NOx. Preliminary results from the two most recent field campaigns indicate that trucks without diesel particle filters emit 4 times more BC than filter-equipped trucks. Diesel particle filters increase emissions of NO2, however, and filter-equipped trucks have NO2/NOx ratios that are 4 to 7 times greater than trucks without filters. Preliminary findings related to particle size distribution indicate that (a) most trucks emitted particles characterized by a single mode of approximately

  20. The impact of inland ships and recreational boats on measured NOx and ultrafine particle concentrations along the waterways

    NASA Astrophysics Data System (ADS)

    van der Zee, Saskia C.; Dijkema, Marieke B. A.; van der Laan, Jorrit; Hoek, Gerard

    2012-08-01

    In Amsterdam, many inhabitants reside in proximity to inland waters. The aim of this study was to assess the impact of passing inland ships and recreational boats, including touring boats, on the air quality near houses close to the water. A measurement campaign was performed at five sites in Amsterdam. Two sites were located along the inland waterways used by cargo ships and recreational boats. The other three sites were located along the canals in the historical city centre, used by touring boats and private recreational boats. At each site, measurements were performed at the waterside and at the facade of houses. Nitrogen oxides (NO and NO2) and ultrafine particles (particle number (PN) concentration), were measured continuously during one afternoon per site, while time and type of passing ships and road traffic was registered. Linear regression analysis was used to analyze the association between passing ships and concentration, adjusted for passing road traffic. There was substantial variation in the impact of passing ships on concentrations at each measuring site, as well as between sites. On average, cargo ships contributed 5 and 4 μg m-3 to NO and NO2, respectively, and 3000 particles cm-3 to PN concentration near houses during the sampling period. Peak concentrations were occasionally substantially higher. Emissions from touring boats had a small but significant impact on NO concentration near houses but not on NO2, with the exception of one site located near the edge of two canals, where boats use extra power to travel around the bent. At this site, touring boats contributed 5 μg m-3 to the local NO2 concentration. No consistent impact of touring boats on PN concentration was observed. Emissions from private recreational boats were not consistently associated with increased NOx or PN concentration. Road traffic intensity was low at the selected measurement sites. Nevertheless, a significant impact of passing diesel-operated delivery vans on house

  1. Air quality in the German-Czech border region: A focus on harmful fractions of PM and ultrafine particles

    NASA Astrophysics Data System (ADS)

    Schladitz, Alexander; Leníček, Jan; Beneš, Ivan; Kováč, Martin; Skorkovský, Jiří; Soukup, Aleš; Jandlová, Jana; Poulain, Laurent; Plachá, Helena; Löschau, Gunter; Wiedensohler, Alfred

    2015-12-01

    A comprehensive air quality study has been carried out at two urban background sites in Annaberg-Buchholz (Germany) and Ústí nad Labem (Czech Republic) in the German-Czech border region between January 2012 and June 2014. Special attention was paid to quantify harmful fractions of particulate matter (PM) and ultrafine particle number concentration (UFP) from solid fuel combustion and vehicular traffic. Source type contributions of UFP were quantified by using the daily concentration courses of UFP and nitrogen oxide. Two different source apportionment techniques were used to quantify relative and absolute mass contributions: positive matrix factorization for total PM2.5 and elemental carbon in PM2.5 and chemical mass balance for total PM1 and organic carbon in PM1. Contributions from solid fuel combustion strongly differed between the non-heating period (April-September) and the heating period (October-March). Major sources of solid fuel combustion in this study were wood and domestic coal combustion, while the proportion of industrial coal combustion was low (<3%). In Ústí nad Labem combustion of domestic brown coal was the most important source of organic carbon ranging from 34% to 43%. Wood combustion was an important source of organic carbon in Annaberg-Buchholz throughout the year. Heavy metals and less volatile polycyclic aromatic hydrocarbons (PAH) in the accumulation mode were related to solid fuel combustion with enhanced concentrations during the heating period. In contrast, vehicular PAH emissions were allocated to the Aitken mode. Only in Ústí nad Labem a significant contribution of photochemical new particle formation (e.g. from sulfur dioxide) to UFP of almost 50% was observed during noontime. UFPs from traffic emissions (nucleation particles) and primary emitted soot particles dominated at both sites during the rest of the day. The methodology of a combined source apportionment of UFP and PM can be adapted to other regions of the world with

  2. Fine and ultrafine particles generated during fluidized bed combustion of different solid fuels

    SciTech Connect

    Urciuolo, M.; Barone, A.; D'Alessio, A.; Chirone, R.

    2008-12-15

    The paper reports an experimental study carried out with a 110-mm ID fluidized bed combustor focused on the characterization of particulates formation/emission during combustion of coal and non-fossil solid fuels. Fuels included: a bituminous coal, a commercial predried and granulated sludge (GS), a refuse-derived fuel (RDF), and a biomass waste (pine seed shells). Stationary combustion experiments were carried out analyzing the fate of fuel ashes. Fly ashes collected at the combustor exhaust were characterized both in terms of particle size distribution and chemical composition, with respect to both trace and major elements. Tapping-Mode Atomic Force Microscopy (TM-AFM) technique and high-efficiency cyclone-type collector devices were used to characterize the size and morphology of the nanometric-and micronic-size fractions of fly ash emitted at the exhaust respectively. Results showed that during the combustion process: I) the size of the nanometric fraction ranges between 2 and 65 nm; ii) depending on the fuel tested, combustion-assisted attrition or the production of the primary ash particles originally present in the fuel particles, are responsible of fine particle generation. The amount in the fly ash of inorganic compounds is larger for the waste-derived fuels, reflecting the large inherent content of these compounds in the parent fuels.

  3. Estimation of ultrafine particle concentrations at near-highway residences using data from local and central monitors

    NASA Astrophysics Data System (ADS)

    Fuller, Christina H.; Brugge, Doug; Williams, Paige L.; Mittleman, Murray A.; Durant, John L.; Spengler, John D.

    2012-09-01

    Ultrafine particles (UFP; aerodynamic diameter < 0.1 μm) are a ubiquitous exposure in the urban environment and are elevated near highways. Most epidemiological studies of UFP health effects use central site monitoring data, which may misclassify exposure. Our aims were to: (1) examine the relationship between distant and proximate monitoring sites and their ability to predict hourly UFP concentration measured at residences in an urban community with a major interstate highway and; (2) determine if meteorology and proximity to traffic improve explanatory power. Short-term (1-3 weeks) residential monitoring of UFP concentration was conducted at 18 homes. Long-term monitoring was conducted at two near-highway monitoring sites and a central site. We created models of outdoor residential UFP concentration based on concentrations at the near-highway site, at the central site, at both sites together and without fixed sites. UFP concentration at residential sites was more highly correlated with those at a near-highway site than a central site. In regression models of each site alone, a 10% increase in UFP concentration at a near-highway site was associated with a 6% (95% CI: 6%, 7%) increase at residences while a 10% increase in UFP concentration at the central site was associated with a 3% (95% CI: 2%, 3%) increase at residences. A model including both sites showed minimal change in the magnitude of the association between the near-highway site and the residences, but the estimated association with UFP concentration at the central site was substantially attenuated. These associations remained after adjustment for other significant predictors of residential UFP concentration, including distance from highway, wind speed, wind direction, highway traffic volume and precipitation. The use of a central site as an estimate of personal exposure for populations near local emissions of traffic-related air pollutants may result in exposure misclassification.

  4. Estimation of ultrafine particle concentrations at near-highway residences using data from local and central monitors.

    PubMed

    Fuller, Christina H; Brugge, Doug; Williams, Paige; Mittleman, Murray; Durant, John L; Spengler, John D

    2012-09-01

    Ultrafine particles (UFP; aerodynamic diameter < 0.1 micrometers) are a ubiquitous exposure in the urban environment and are elevated near highways. Most epidemiological studies of UFP health effects use central site monitoring data, which may misclassify exposure. Our aims were to: (1) examine the relationship between distant and proximate monitoring sites and their ability to predict hourly UFP concentration measured at residences in an urban community with a major interstate highway and; (2) determine if meteorology and proximity to traffic improve explanatory power. Short-term (1 - 3 weeks) residential monitoring of UFP concentration was conducted at 18 homes. Long-term monitoring was conducted at two near-highway monitoring sites and a central site. We created models of outdoor residential UFP concentration based on concentrations at the near-highway site, at the central site, at both sites together and without fixed sites. UFP concentration at residential sites was more highly correlated with those at a near-highway site than a central site. In regression models of each site alone, a 10% increase in UFP concentration at a near-highway site was associated with a 6% (95% CI: 6%, 7%) increase at residences while a 10% increase in UFP concentration at the central site was associated with a 3% (95% CI: 2%, 3%) increase at residences. A model including both sites showed minimal change in the magnitude of the association between the near-highway site and the residences, but the estimated association with UFP concentration at the central site was substantially attenuated. These associations remained after adjustment for other significant predictors of residential UFP concentration, including distance from highway, wind speed, wind direction, highway traffic volume and precipitation. The use of a central site as an estimate of personal exposure for populations near local emissions of traffic-related air pollutants may result in exposure misclassification.

  5. Estimation of ultrafine particle concentrations at near-highway residences using data from local and central monitors

    PubMed Central

    Fuller, Christina H.; Brugge, Doug; Williams, Paige; Mittleman, Murray; Durant, John L.; Spengler, John D.

    2012-01-01

    Ultrafine particles (UFP; aerodynamic diameter < 0.1 micrometers) are a ubiquitous exposure in the urban environment and are elevated near highways. Most epidemiological studies of UFP health effects use central site monitoring data, which may misclassify exposure. Our aims were to: (1) examine the relationship between distant and proximate monitoring sites and their ability to predict hourly UFP concentration measured at residences in an urban community with a major interstate highway and; (2) determine if meteorology and proximity to traffic improve explanatory power. Short-term (1 – 3 weeks) residential monitoring of UFP concentration was conducted at 18 homes. Long-term monitoring was conducted at two near-highway monitoring sites and a central site. We created models of outdoor residential UFP concentration based on concentrations at the near-highway site, at the central site, at both sites together and without fixed sites. UFP concentration at residential sites was more highly correlated with those at a near-highway site than a central site. In regression models of each site alone, a 10% increase in UFP concentration at a near-highway site was associated with a 6% (95% CI: 6%, 7%) increase at residences while a 10% increase in UFP concentration at the central site was associated with a 3% (95% CI: 2%, 3%) increase at residences. A model including both sites showed minimal change in the magnitude of the association between the near-highway site and the residences, but the estimated association with UFP concentration at the central site was substantially attenuated. These associations remained after adjustment for other significant predictors of residential UFP concentration, including distance from highway, wind speed, wind direction, highway traffic volume and precipitation. The use of a central site as an estimate of personal exposure for populations near local emissions of traffic-related air pollutants may result in exposure misclassification. PMID

  6. Redox Dynamics of Mixed Metal (Mn, Cr, and Fe) Ultrafine Particles

    SciTech Connect

    Nico, Peter S.; Kumfer, Benjamin M.; Kennedy, Ian M.; Anastasio, Cort

    2008-08-01

    The impact of particle composition on metal oxidation state, and on changes in oxidation state with simulated atmospheric aging, are investigated experimentally in flame-generated nanoparticles containing Mn, Cr, and Fe. The results demonstrate that the initial fraction of Cr(VI) within the particles decreases with increasing total metal concentration in the flame. In contrast, the initial Mn oxidation state was only partly controlled by metal loading, suggesting the importance of other factors. Two reaction pathways, one reductive and one oxidative, were found to be operating simultaneously during simulated atmospheric aging. The oxidative pathway depended upon the presence of simulated sunlight and O{sub 3}, whereas the reductive pathway occurred in the presence of simulated sunlight alone. The reductive pathway appears to be rapid but transient, allowing the oxidative pathway to dominate with longer aging times, i.e. greater than {approx}8 hours. The presence of Mn within the particles enhanced the importance of the oxidative pathway, leading to more net Cr oxidation during aging implying that Mn can mediate oxidation by removal of electrons from other particulate metals.

  7. Assessment of ultrafine particles and noise measurements using fuzzy logic and data mining techniques.

    PubMed

    Fernández-Camacho, R; Brito Cabeza, I; Aroba, J; Gómez-Bravo, F; Rodríguez, S; de la Rosa, J

    2015-04-15

    This study focuses on correlations between total number concentrations, road traffic emissions and noise levels in an urban area in the southwest of Spain during the winter and summer of 2009. The high temporal correlation between sound pressure levels, traffic intensity, particle number concentrations related to traffic, black carbon and NOx concentrations suggests that noise is linked to traffic emissions as a main source of pollution in urban areas. First, the association of these different variables was studied using PreFuRGe, a computational tool based on data mining and fuzzy logic. The results showed a clear association between noise levels and road-traffic intensity for non-extremely high wind speed levels. This behaviour points, therefore, to vehicular emissions being the main source of urban noise. An analysis for estimating the total number concentration from noise levels is also proposed in the study. The high linearity observed between particle number concentrations linked to traffic and noise levels with road traffic intensity can be used to calculate traffic related particle number concentrations experimentally. At low wind speeds, there are increases in noise levels of 1 dB for every 100 vehicles in circulation. This is equivalent to 2000 cm(-3) per vehicle in winter and 500 cm(-3) in summer. At high wind speeds, wind speed could be taken into account. This methodology allows low cost sensors to be used as a proxy for total number concentration monitoring in urban air quality networks.

  8. Redox Dynamics of Mixed Metal (Mn, Cr, and Fe) Ultrafine Particles

    PubMed Central

    Nico, Peter S.; Kumfer, Benjamin M.; Kennedy, Ian M.; Anastasio, Cort

    2008-01-01

    The impact of particle composition on metal oxidation state, and on changes in oxidation state with simulated atmospheric aging, are investigated experimentally in flame-generated nanoparticles containing Mn, Cr, and Fe. The results demonstrate that the initial fraction of Cr(VI) within the particles decreases with increasing total metal concentration in the flame. In contrast, the initial Mn oxidation state was only partly controlled by metal loading, suggesting the importance of other factors. Two reaction pathways, one reductive and one oxidative, were found to be operating simultaneously during simulated atmospheric aging. The oxidative pathway depended upon the presence of simulated sunlight and O3, whereas the reductive pathway occurred in the presence of simulated sunlight alone. The reductive pathway appears to be rapid but transient, allowing the oxidative pathway to dominate with longer aging times, i.e. greater than ∼8 hours. The presence of Mn within the particles enhanced the importance of the oxidative pathway, leading to more net Cr oxidation during aging implying that Mn can mediate oxidation by removal of electrons from other particulate metals. PMID:20046215

  9. Ultrafine cementitious grout

    SciTech Connect

    Ahrens, E.H.

    1999-10-19

    An ultrafine cementitious grout in three particle grades containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 30 wt. % to about 70 wt. % Portland cement; from about 30 wt. % to about 70 wt. % pumice containing at least 70% amorphous silicon dioxide; and from 1.2 wt. % to about 5.0 wt. % superplasticizer. The superplasticizer is dispersed in the mixing water prior to the addition of dry grout and the W/CM ratio is about 0.4 to 1/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 {mu}m in width.

  10. Ultrafine cementitious grout

    DOEpatents

    Ahrens, Ernst H.

    1999-01-01

    An ultrafine cementitious grout in three particle grades containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 30 wt. % to about 70 wt. % Portland cement; from about 30 wt. % to about 70 wt. % pumice containing at least 70% amorphous silicon dioxide; and from 1.2 wt. % to about 5.0 wt. % superplasticizer. The superplasticizer is dispersed in the mixing water prior to the addition of dry grout and the W/CM ratio is about 0.4 to 1/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 .mu.m in width.

  11. Ultrafine cementitious grout

    DOEpatents

    Ahrens, Ernst H.

    1998-01-01

    An ultrafine cementitious grout having a particle size 90% of which are less than 6 .mu.m in diameter and an average size of about 2.5 .mu.m or less, and preferably 90% of which are less than 5 .mu.m in diameter and an average size of about 2 .mu.m or less containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 40 wt. % to about 50 wt. % Portland cement; from about 50 wt. % to about 60 wt. % pumice containing at least 60% amorphous silicon dioxide; and from 0.1 wt. % to about 1.5 wt. % superplasticizer. The grout is mixed with water in the W/CM ratio of about 0.4-0.6/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 .mu.m in width.

  12. PAH, BTEX, carbonyl compound, black-carbon, NO2 and ultrafine particle dynamometer bench emissions for Euro 4 and Euro 5 diesel and gasoline passenger cars

    NASA Astrophysics Data System (ADS)

    Louis, Cédric; Liu, Yao; Tassel, Patrick; Perret, Pascal; Chaumond, Agnès; André, Michel

    2016-09-01

    Although implementing Diesel particulate filters (DPF) and other novel aftertreatment technologies makes it possible to achieve significant reductions in particle mass emissions, it may induce the release of ultrafine particles and emissions of many other unregulated compounds. This paper focuses on (i) ultrafine particles, black carbon, BTEX, PAH, carbonyl compounds, and NO2 emissions from Euro 4 and Euro 5 Diesel and gasoline passenger cars, (ii) the influence of driving conditions (e.g., cold start, urban, rural and motorway conditions), and (iii) the impact of additive and catalysed DPF devices on vehicle emissions. Chassis dynamometer tests were conducted on four Euro 5 vehicles and two Euro 4 vehicles: gasoline vehicles with and without direct injection system and Diesel vehicles equipped with additive and catalysed particulate filters. The results showed that compared to hot-start cycles, cold-start urban cycles increased all pollutant emissions by a factor of two. The sole exception was NO2, which was reduced by a factor of 1.3-6. Particulate and black carbon emissions from the gasoline engines were significantly higher than those from the Diesel engines equipped with DPF. Moreover, the catalysed DPF emitted about 3-10 times more carbonyl compounds and particles than additive DPF, respectively, during urban driving cycles, while the additive DPF vehicles emitted 2 and 5 times more BTEX and carbonyl compounds during motorway driving cycles. Regarding particle number distribution, the motorway driving cycle induced the emission of particles smaller in diameter (mode at 15 nm) than the urban cold-start cycle (mode at 80-100 nm). The results showed a clear positive correlation between particle, black carbon, and BTEX emissions, and a negative correlation between particles and NO2.

  13. Source apportionment of size segregated fine/ultrafine particle by PMF in Beijing

    NASA Astrophysics Data System (ADS)

    Tan, Ji-hua; Duan, Jing-chun; Chai, Fa-he; He, Ke-bin; Hao, Ji-Ming

    2014-03-01

    Considering the adverse health effects to human body, the number concentration of atmospheric PM (particulate material) is more important than the mass concentration. CO, NO, NO2, SO2 and number concentrations of PM were obtained from a remote site (Miyun), a roadside site (North Fourth Ring Road) and an urban residential site (Tsinghua University) in Beijing in winter. The size distribution and the possible sources of number concentrations were examined using EPA PMF (positive matrix factorization) model. A data set of totally 9610 of number concentration with the size range of 0.028 μm to 0.948 μm was included in the PMF analysis. The highest total particle number, mass and area of fine particles concentrations were observed at the North Fourth Ring Road site and the lowest were observed at Miyun site. Four factors were identified at Miyun site, as Factor 1 and Factor 4 may be related to long distance transportation, and Factor 2 and Factor 3 may be assigned as coal combustion and locomotive emission nearby, respectively; three factors were identified at North Fourth Ring Road, of which Factor 1 and Factor 3 are traffic related and Factor 2 may be coal combustion related. Compared with Factor 1, the contributions of Factor 3 to NOx and SO2 were 4-5 times higher. Additionally, Factor 3 was also a major contributor to CO. It suggested that Factor 1 and Factor 3 had the same source emission of motor vehicle, but different engine types, fuel types or exhaust treatments. Three factors were identified at Tsinghua site, as Factor 1 may come from aging vehicle emission, and Factor 2 and Factor 3 may be coal combustion related.

  14. Modeling of in situ ultrafine atmospheric particle formation in the eastern United States

    NASA Astrophysics Data System (ADS)

    Gaydos, Timothy M.; Stanier, Charles O.; Pandis, Spyros N.

    2005-04-01

    The creation of new atmospheric particles from in situ nucleation influences climate through cloud-aerosol interactions and may negatively impact human health. Although recent observations show that nucleation is widespread in the eastern United States, the corresponding pathways remain uncertain. Combining extensive field measurements in Pittsburgh, Pennsylvania, with an aerosol dynamics and chemistry model assuming ternary NH3-H2SO4-H2O nuclei formation, we show excellent model-measurement agreement and predictive capability. The ternary NH3-H2SO4-H2O nucleation model is successful in predicting the presence or lack of nucleation on 19 out of 19 days with complete data sets in July 2001 and on 25 out of 29 days in January 2002. Reductions of ammonia emissions are predicted to decrease the frequency of nucleation events during both summer and winter, with a more dramatic effect during the summer. The response to changes in emissions of sulfur dioxide during the summer is counterintuitive. Reductions of sulfur dioxide and the resulting sulfate by up to 40% actually increase the frequency of the summer nucleation events. Modeling predicts the opposite effect in winter, with reductions of sulfur dioxide leading to fewer nucleation events.

  15. FORMATION OF FINE PARTICLES FROM RESIDUAL OIL COMBUSTION: REDUCING ULTRAFINE NUCLEI THROUGH THE ADDITION OF INORGANIC SORBENT

    EPA Science Inventory

    The paper gives results of an investigation, using an 82-kW-rated laboratory-scale refractory-lined combustor, of the characteristics of particulate matter emitted from residual oil combustion and the reduction of ultrafine nuclei by postflame sorbent injection. Without sorbent a...

  16. X-ray diffraction investigation of ultrafine boron nitride powders

    SciTech Connect

    Gurov, S.V.; Chukalin, V.I.; Rezchikova, T.V.; Torbov, V.J.; Troitskii, V.N.

    1986-01-01

    This paper presents an x-ray diffraction analysis of ultrafine boron nitride powders of different mean particle sizes. Diffraction spectra of the ultrafine boron nitride powders were obtained using a DRON-1 apparatus. The experimental facts are indicative of a turbostratic character of deformation of the hexagonal lattice of ultrafinely divided boron nitride.

  17. A land use regression model for ambient ultrafine particles in Montreal, Canada: A comparison of linear regression and a machine learning approach.

    PubMed

    Weichenthal, Scott; Ryswyk, Keith Van; Goldstein, Alon; Bagg, Scott; Shekkarizfard, Maryam; Hatzopoulou, Marianne

    2016-04-01

    Existing evidence suggests that ambient ultrafine particles (UFPs) (<0.1µm) may contribute to acute cardiorespiratory morbidity. However, few studies have examined the long-term health effects of these pollutants owing in part to a need for exposure surfaces that can be applied in large population-based studies. To address this need, we developed a land use regression model for UFPs in Montreal, Canada using mobile monitoring data collected from 414 road segments during the summer and winter months between 2011 and 2012. Two different approaches were examined for model development including standard multivariable linear regression and a machine learning approach (kernel-based regularized least squares (KRLS)) that learns the functional form of covariate impacts on ambient UFP concentrations from the data. The final models included parameters for population density, ambient temperature and wind speed, land use parameters (park space and open space), length of local roads and rail, and estimated annual average NOx emissions from traffic. The final multivariable linear regression model explained 62% of the spatial variation in ambient UFP concentrations whereas the KRLS model explained 79% of the variance. The KRLS model performed slightly better than the linear regression model when evaluated using an external dataset (R(2)=0.58 vs. 0.55) or a cross-validation procedure (R(2)=0.67 vs. 0.60). In general, our findings suggest that the KRLS approach may offer modest improvements in predictive performance compared to standard multivariable linear regression models used to estimate spatial variations in ambient UFPs. However, differences in predictive performance were not statistically significant when evaluated using the cross-validation procedure.

  18. Development and characterization of metal-diboride-based composites toughened with ultra-fine SiC particulates

    NASA Astrophysics Data System (ADS)

    Monteverde, Frédéric; Bellosi, Alida

    2005-05-01

    Two metal-diboride-based ceramics containing up to 15 vol%. ultra-fine α-SiC particulates were developed from commercially available powders. The primary matrix of the composites was ZrB 2 or a mixture of ZrB 2 and HfB 2. With the assistance of 4.5 vol%. ZrN as a sintering aid, both the compositions achieved nearly full density after hot-pressing at 1,900 °C. The microstructure was characterized by fine diboride grains ( ≈3 μm average size) and SiC particles dispersed uniformly. Limited amounts of secondary phases like MO 2 and M(C,N), M=Zr or Zr/Hf, were found. The thermo-mechanical data of both the materials offered a promising combination of properties: about 16 GPa of micro-hardness, 5 MPa√ m of fracture toughness and Young's moduli exceeding 470 GPa. The ZrB 2sbnd SiC composite showed values of strength in air of 635 ± 60 and 175 ± 15 MPa at 25 and 1,500 °C, respectively. Likewise, the (ZrB 2 + HfB 2) sbnd SiC composite exhibited values of strength in air of 590 ± 25 and 190 ± 20 MPa at 25 and 1,500 °C, respectively. The composites also displayed good tolerance of conditions of repeated short exposures, 10 minutes each, at 1,700 °C in stagnant air. In such oxidizing conditions, the resistance to oxidation was provided by the formation of a protective silica-based glass coating, the primary oxidation product of SiC. Such a coating encapsulated the specimen coherently, and provided protection to the faces exposed to the hot atmosphere.

  19. Indoor ultrafine particle exposures and home heating systems: a cross-sectional survey of Canadian homes during the winter months.

    PubMed

    Weichenthal, Scott; Dufresne, Andre; Infante-Rivard, Claire; Joseph, Lawrence

    2007-05-01

    Exposure to airborne particulate matter has a negative effect on respiratory health in both children and adults. Ultrafine particle (UFP) exposures are of particular concern owing to their enhanced ability to cause oxidative stress and inflammation in the lungs. In this investigation, our objective was to examine the contribution of home heating systems (electric baseboard heaters, wood stoves, forced-air oil/natural gas furnace) to indoor UFP exposures. We conducted a cross-sectional survey in 36 homes in the cities of Montréal, Québec, and Pembroke, Ontario. Real-time measures of indoor UFP concentrations were collected in each home for approximately 14 h, and an outdoor UFP measurement was collected outside each home before indoor sampling. A home-characteristic questionnaire was also administered, and air exchange rates were estimated using carbon dioxide as a tracer gas. Average UFP exposures of 21,594 cm(-3) (95% confidence interval (CI): 14,014, 29,174) and 6660 cm(-3) (95% CI: 4339, 8982) were observed for the evening (1600-2400) and overnight (2400-0800) hours, respectively. In an unadjusted comparison, overnight baseline UFP exposures were significantly greater in homes with electric baseboard heaters as compared to homes using forced-air oil or natural gas furnaces, and homes using wood stoves had significantly greater overnight baseline UFP exposures than homes using forced-air natural gas furnaces. However, in multivariate models, electric oven use (beta=12,253 cm(-3), 95% CI: 3524, 20,982), indoor relative humidity (beta=1136 cm(-3) %, 95% CI: 372, 1899), and indoor smoking (beta=18,192 cm(-3), 95% CI: 2073, 34,311) were the only significant determinants of mean indoor UFP exposure, whereas air exchange rate (beta=4351 cm(-3) h(-1), 95% CI: 1507, 7195) and each 10,000 cm(-3) increase in outdoor UFPs (beta=811 cm(-3), 95% CI: 244,1377) were the only significant determinants of overnight baseline UFP exposures. In general, our findings suggest that

  20. Relaxation in ordered systems of ultrafine magnetic particles: effect of the exchange interaction.

    PubMed

    Russ, Stefanie; Bunde, Armin

    2011-03-30

    We perform Monte Carlo simulations to study the relaxation of single-domain nanoparticles that are located on a simple cubic lattice with anisotropy axes pointing in the z-direction, under the combined influence of anisotropy energy, dipolar interaction and ferromagnetic interaction of strength J. We compare the results of classical Heisenberg systems with three-dimensional magnetic moments [Formula: see text] to those of Ising systems and find that Heisenberg systems show a much richer and more complex dynamical behavior. In contrast to Heisenberg systems, Ising systems need large activation energies to turn a spin and also possess a smaller configuration space for the orientation of the [Formula: see text]. Accordingly, Heisenberg systems possess a whole landscape of different states with very close-lying energies, while Ising systems tend to get frozen in one random state far away from the ground state. For Heisenberg systems, we identify two phase transitions: (i) at intermediate J between domain and layered states and (ii) at larger J between layered and ferromagnetic states. Between these two transitions, the layered states change their appearance and develop a sub-structure, where the orientation of the [Formula: see text] in each layer depends on J, so that for each value of J, a new ground state appears.

  1. Endocytosis, oxidative stress and IL-8 expression in human lung epithelial cells upon treatment with fine and ultrafine TiO{sub 2}: Role of the specific surface area and of surface methylation of the particles

    SciTech Connect

    Singh, Seema |; Shi, Tingming |; Duffin, Rodger |; Albrecht, Catrin; Berlo, Damien van; Hoehr, Doris; Fubini, Bice; Martra, Gianmario; Fenoglio, Ivana; Borm, Paul J.A. |; Schins, Roel P.F. . E-mail: roel.schins@uni-duesseldorf.de

    2007-07-15

    Inhaled ultrafine particles show considerably stronger pulmonary inflammatory effects when tested at equal mass dose with their fine counterparts. However, the responsible mechanisms are not yet fully understood. We investigated the role of particle size and surface chemistry in initiating pro-inflammatory effects in vitro in A549 human lung epithelial cells on treatment with different model TiO{sub 2} particles. Two samples of TiO{sub 2}, i.e. fine (40-300 nm) and ultrafine (20-80 nm) were tested in their native forms as well as upon surface methylation, as was confirmed by Fourier transformed infrared spectroscopy. Radical generation during cell treatment was determined by electron paramagnetic resonance with 5,5-dimethyl-1-pyrroline-N-oxide or 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl. Interleukin-8 mRNA expression/release was determined by RT-PCR and ELISA, whereas particle uptake was evaluated by transmission electron microscopy. TiO{sub 2} particles were rapidly taken up by the cells, generally as membrane bound aggregates and large intracellular aggregates in vesicles, vacuoles and lamellar bodies. Aggregate size tended to be smaller for the ultrafine samples and was also smaller for methylated fine TiO{sub 2} when compared to non-methylated fine TiO{sub 2}. No particles were observed inside nuclei or any other vital organelle. Both ultrafine TiO{sub 2} samples but not their fine counterparts elicited significantly stronger oxidant generation and IL-8 release, despite their aggregation state and irrespective of their methylation. The present data indicate that ultrafine TiO{sub 2}, even as aggregates/agglomerates, can trigger inflammatory responses that appear to be driven by their large surface area. Furthermore, our results indicate that these effects result from oxidants generated during particle-cell interactions through a yet to be elucidated mechanism(s)

  2. Effects of ultrafine particles on the allergic inflammation in the lung of asthmatics: results of a double-blinded randomized cross-over clinical pilot study

    PubMed Central

    2014-01-01

    Background Epidemiological and experimental studies suggest that exposure to ultrafine particles (UFP) might aggravate the allergic inflammation of the lung in asthmatics. Methods We exposed 12 allergic asthmatics in two subgroups in a double-blinded randomized cross-over design, first to freshly generated ultrafine carbon particles (64 μg/m3; 6.1 ± 0.4 × 105 particles/cm3 for 2 h) and then to filtered air or vice versa with a 28-day recovery period in-between. Eighteen hours after each exposure, grass pollen was instilled into a lung lobe via bronchoscopy. Another 24 hours later, inflammatory cells were collected by means of bronchoalveolar lavage (BAL). (Trial registration: NCT00527462) Results For the entire study group, inhalation of UFP by itself had no significant effect on the allergen induced inflammatory response measured with total cell count as compared to exposure with filtered air (p = 0.188). However, the subgroup of subjects, which inhaled UFP during the first exposure, exhibited a significant increase in total BAL cells (p = 0.021), eosinophils (p = 0.031) and monocytes (p = 0.013) after filtered air exposure and subsequent allergen challenge 28 days later. Additionally, the potential of BAL cells to generate oxidant radicals was significantly elevated at that time point. The subgroup that was exposed first to filtered air and 28 days later to UFP did not reveal differences between sessions. Conclusions Our data demonstrate that pre-allergen exposure to UFP had no acute effect on the allergic inflammation. However, the subgroup analysis lead to the speculation that inhaled UFP particles might have a long-term effect on the inflammatory course in asthmatic patients. This should be reconfirmed in further studies with an appropriate study design and sufficient number of subjects. PMID:25204642

  3. Ultrafine particle levels at an international port of entry between the US and Mexico: exposure implications for users, workers, and neighbors.

    PubMed

    Olvera, Hector A; Lopez, Mario; Guerrero, Veronica; Garcia, Humberto; Li, Wen-Whai

    2013-01-01

    Exposure to diesel-emitted particles has been linked to increased cancer risk and cardiopulmonary diseases. Because of their size (<100 nm), exposure to ultrafine particles (UFPs) emitted from heavy-duty diesel vehicles (HDDV) might result in greater health risks than those associated with larger particles. Seasonal UFP levels at the International Bridge of the Americas, which connects the US and Mexico and has high HDDV traffic demands, were characterized. Hourly average UFP concentrations ranged between 1.7 × 10(3)/cc and 2.9 × 10(5)/cc with a mean of 3.5 × 10(4)/cc. Wind speeds <2 m s(-1) and temperatures <15 °C were associated with particle number concentrations above normal conditions. The presence of HDDV had the strongest impact on local UFP levels. Varying particle size distributions were associated with south- and northbound HDDV traffic. Peak exposure occurred on weekday afternoons. Although in winter, high exposure episodes were also observed in the morning. Particle number concentrations were estimated to reach background levels at 400 m away from traffic. The populations exposed to UFP above background levels include law enforcement officers, street vendors, private commuters, and commercial vehicle drivers as well as neighbors on both sides of the border, including a church and several schools.

  4. Deposition velocity of ultrafine particles measured with the Eddy-Correlation Method over the Nansen Ice Sheet (Antarctica)

    NASA Astrophysics Data System (ADS)

    Contini, D.; Donateo, A.; Belosi, F.; Grasso, F. M.; Santachiara, G.; Prodi, F.

    2010-08-01

    This work reports an analysis of the concentration, size distribution, and deposition velocity of atmospheric particles over snow and iced surfaces on the Nansen Ice Sheet (Antarctica). Measurements were performed using the eddy-correlation method at a remote site during the XXII Italian expedition of the National Research Program in Antarctica (PNRA) in 2006. The measurement system was based on a condensation particle counter (CPC) able to measure particles down to 9 nm in diameter with a 50% efficiency and a Differential Mobility Particle Sizer for evaluating particle size distributions from 11 to 521 nm diameter in 39 channels. A method based on postprocessing with digital filters was developed to take into account the effect of the slow time response of the CPC. The average number concentration was 1338 cm-3 (median, 978 cm-3; interquartile range, 435-1854 cm-3). Higher concentrations were observed at low wind velocities. Results gave an average deposition velocity of 0.47 mm/s (median, 0.19 mm/s; interquartile range, -0.21 -0.88 mm/s). Deposition increased with the friction velocity and was on average 0.86 mm/s during katabatic wind characterized by velocities higher than 4 m/s. Observed size distributions generally presented two distinct modes, the first at approximately 15-20 nm and the second (representing on average 70% of the total particles) at 60-70 nm. Under strong-wind conditions, the second mode dominated the average size distribution.

  5. One-step thermolysis synthesis of two-dimensional ultrafine Fe3O4 particles/carbon nanonetworks for high-performance lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Wanqun; Li, Xiaona; Liang, Jianwen; Tang, Kaibin; Zhu, Yongchun; Qian, Yitai

    2016-02-01

    To tackle the issue of inferior cycle stability and rate capability for Fe3O4 anode materials in lithium ion batteries, ultrafine Fe3O4 nanocrystals uniformly encapsulated in two-dimensional (2D) carbon nanonetworks have been fabricated through thermolysis of a simple, low-cost iron(iii) acetylacetonate without any extra processes. Moreover, compared to the reported Fe3O4/carbon composites, the particle size of Fe3O4 is controllable and held down to ~3 nm. Benefitting from the synergistic effects of the excellent electroconductive carbon nanonetworks and uniform distribution of ultrafine Fe3O4 particles, the prepared 2D Fe3O4/carbon nanonetwork anode exhibits high reversible capacity, excellent rate capability and superior cyclability. A high capacity of 1534 mA h g-1 is achieved at a 1 C rate and is maintained without decay up to 500 cycles (1 C = 1 A g-1). Even at the high current density of 5 C and 10 C, the 2D Fe3O4/carbon nanonetworks maintain a reversible capacity of 845 and 647 mA h g-1 after 500 discharge/charge cycles, respectively. In comparison with other reported Fe3O4-based anodes, the 2D Fe3O4/carbon nanonetwork electrode is one of the most attractive of those in energy storage applications.To tackle the issue of inferior cycle stability and rate capability for Fe3O4 anode materials in lithium ion batteries, ultrafine Fe3O4 nanocrystals uniformly encapsulated in two-dimensional (2D) carbon nanonetworks have been fabricated through thermolysis of a simple, low-cost iron(iii) acetylacetonate without any extra processes. Moreover, compared to the reported Fe3O4/carbon composites, the particle size of Fe3O4 is controllable and held down to ~3 nm. Benefitting from the synergistic effects of the excellent electroconductive carbon nanonetworks and uniform distribution of ultrafine Fe3O4 particles, the prepared 2D Fe3O4/carbon nanonetwork anode exhibits high reversible capacity, excellent rate capability and superior cyclability. A high capacity of 1534 mA h

  6. Continuous Production of Aqueous Suspensions of Ultra-fine Particles of Curcumin using Ultrasonically Driven Mixing Device.

    PubMed

    Pandey, Komal; Chatte, Amruta B; Dalvi, Sameer V

    2017-04-03

    Developing drug formulations for poorly water soluble drugs is a major challenge for pharmaceutical industries as the poor water solubility limits bioavailability of these drugs. Production of nanoparticles/microparticles of these drugs is one of the ways to improve dissolution rates by increasing interfacial area for dissolution. Curcumin, a compound obtained from the rhizome of curcuma longa (turmeric roots), is a pharmaceutically viable molecule. However, poor aqueous solubility limits its therapeutic use. In this work, we report studies conducted to continuously produce aqueous suspensions of curcumin nano/micro particles. Influence of process parameters such as ultrasound, additives and solvent to antisolvent ratio on polymorphic outcome and morphology of precipitated particles has been investigated. Ultrasound was found to greatly influence the polymorphic form and the morphology of precipitated particles. Nucleation rates, mixing time and solid-liquid interfacial energies were also estimated to understand the effect of various processing parameters on the precipitation process.

  7. Ultrafine particles affect the balance of endogenous pro- and anti-inflammatory lipid mediators in the lung: in-vitro and in-vivo studies

    PubMed Central

    2012-01-01

    Background Exposure to ultrafine particles exerts diverse harmful effects including aggravation of pulmonary diseases like asthma. Recently we demonstrated in a mouse model for allergic airway inflammation that particle-derived oxidative stress plays a crucial role during augmentation of allergen-induced lung inflammation by ultrafine carbon particle (UfCP) inhalation. The mechanisms how particle inhalation might change the inflammatory balance in the lungs, leading to accelerated inflammatory reactions, remain unclear. Lipid mediators, known to be immediately generated in response to tissue injury, might be strong candidates for priming this particle-triggered change of the inflammatory balance. Methods We hypothesize that inhalation of UfCP may disturb the balance of pro- and anti-inflammatory lipid mediators in: i) a model for acute allergic pulmonary inflammation, exposing mice for 24 h before allergen challenge to UfCP inhalation (51.7 nm, 507 μg/m3), and ii) an in-vitro model with primary rat alveolar macrophages (AM) incubated with UfCP (10 μg/1 x 106 cells/ml) for 1 h. Lungs and AM were analysed for pro- and anti-inflammatory lipid mediators, namely leukotriene B4 (LTB4), prostaglandin E2 (PGE2), 15(S)-hydroxy-eicosatetraenoic acid (15(S)-HETE), lipoxin A4 (LXA4) and oxidative stress marker 8-isoprostane by enzyme immunoassays and immunohistochemistry. Results In non-sensitized mice UfCP exposure induced a light non-significant increase of all lipid mediators. Similarly but significantly in rat AM all lipid mediators were induced already within 1 h of UfCP stimulation. Also sensitized and challenge mice exposed to filtered air showed a partially significant increase in all lipid mediators. In sensitized and challenged mice UfCP exposure induced highest significant levels of all lipid mediators in the lungs together with the peak of allergic airway inflammation on day 7 after UfCP inhalation. The levels of LTB4, 8-isoprostane and PGE2 were significantly

  8. Ultrafine cementitious grout

    DOEpatents

    Ahrens, E.H.

    1998-07-07

    An ultrafine cementitious grout is described having a particle size 90% of which are less than 6 {micro}m in diameter and an average size of about 2.5 {micro}m or less, and preferably 90% of which are less than 5 {micro}m in diameter and an average size of about 2 {micro}m or less containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 40 wt. % to about 50 wt. % Portland cement; from about 50 wt. % to about 60 wt. % pumice containing at least 60% amorphous silicon dioxide; and from 0.1 wt. % to about 1.5 wt. % superplasticizer. The grout is mixed with water in the W/CM ratio of about 0.4--0.6/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 {micro}m in width. 4 figs.

  9. Human peripheral blood mononuclear cells (PBMCs) from smokers release higher levels of IL-1-like cytokines after exposure to combustion-generated ultrafine particles.

    PubMed

    De Falco, Gianluigi; Terlizzi, Michela; Sirignano, Mariano; Commodo, Mario; D'Anna, Andrea; Aquino, Rita P; Pinto, Aldo; Sorrentino, Rosalinda

    2017-02-22

    Ultrafine particles (UFP) generated by combustion processes are often associated with adverse health effects. However, little is known about the inflammatory processes generated by UFP that may underlie their toxicological activity. Murine macrophages (J774.1 cells) and human peripheral blood mononuclear cells (PBMCs) were used to evaluate the molecular mechanism underlying the pro-inflammatory activity of UFP. The addition of soot particles to J774.1 cells induced a concentration-dependent release of IL-1α, IL-1β and IL-33 This effect was not associated with cell death and, in contrast to literature, was pronounced at very low concentrations (5-100 pg/ml). Similarly, UFP induced the release of IL-1α, IL-18 and IL-33 by PBMCs. However, this effect was solely observed in PBMCs obtained from smokers, as the PBMCs from non-smokers instead released higher levels of IL-10. The release of these cytokines after UFP exposure was caspase-1- and NLRP3 inflammasome-dependent in PBMCs from healthy smokers, whereas IL-1α release was calpain-dependent. These results show that UFP at very low concentrations are able to give rise to an inflammatory process that is responsible for IL-1α, IL-18 and IL-33 release, which is pronounced in PBMCs from smokers, confirming that these individuals are especially susceptible to inflammatory-based airway diseases once exposed to air pollution.

  10. Microstructural evolution and magnetic properties of ultrafine solute-atom particles formed in a Cu75-Ni20-Fe5 alloy on isothermal annealing

    NASA Astrophysics Data System (ADS)

    Kim, Jun-Seop; Takeda, Mahoto; Bae, Dong-Sik

    2016-12-01

    Microstructural features strongly affect magnetism in nano-granular magnetic materials. In the present work we have investigated the relationship between the magnetic properties and the self-organized microstructure formed in a Cu75-Ni20-Fe5 alloy comprising ferromagnetic elements and copper atoms. High resolution transmission electron microscopy (HRTEM) observations showed that on isothermal annealing at 873 K, nano-scale solute (Fe,Ni)-rich clusters initially formed with a random distribution in the Cu-rich matrix. Superconducting quantum interference device (SQUID) measurements revealed that these ultrafine solute clusters exhibited super-spinglass and superparamagnetic states. On further isothermal annealing the precipitates evolved to cubic or rectangular ferromagnetic particles and aligned along the <100> directions of the copper-rich matrix. Electron energy-band calculations based on the first-principle Korringa-Kohn-Rostocker (KKR) method were also implemented to investigate both the electronic structure and the magnetic properties of the alloy. Inputting compositions obtained experimentally by scanning transmission electron microscopy-electron dispersive X-ray spectroscopy (STEM-EDS) analysis, the KKR calculation confirmed that ferromagnetic precipitates (of moment 1.07μB per atom) formed after annealing for 2 × 104 min. Magneto-thermogravimetric (MTG) analysis determined with high sensitivity the Curie temperatures and magnetic susceptibility above room temperature of samples containing nano-scale ferromagnetic particles.

  11. Human peripheral blood mononuclear cells (PBMCs) from smokers release higher levels of IL-1-like cytokines after exposure to combustion-generated ultrafine particles

    PubMed Central

    De Falco, Gianluigi; Terlizzi, Michela; Sirignano, Mariano; Commodo, Mario; D’Anna, Andrea; Aquino, Rita P.; Pinto, Aldo; Sorrentino, Rosalinda

    2017-01-01

    Ultrafine particles (UFP) generated by combustion processes are often associated with adverse health effects. However, little is known about the inflammatory processes generated by UFP that may underlie their toxicological activity. Murine macrophages (J774.1 cells) and human peripheral blood mononuclear cells (PBMCs) were used to evaluate the molecular mechanism underlying the pro-inflammatory activity of UFP. The addition of soot particles to J774.1 cells induced a concentration-dependent release of IL-1α, IL-1β and IL-33 This effect was not associated with cell death and, in contrast to literature, was pronounced at very low concentrations (5–100 pg/ml). Similarly, UFP induced the release of IL-1α, IL-18 and IL-33 by PBMCs. However, this effect was solely observed in PBMCs obtained from smokers, as the PBMCs from non-smokers instead released higher levels of IL-10. The release of these cytokines after UFP exposure was caspase-1- and NLRP3 inflammasome-dependent in PBMCs from healthy smokers, whereas IL-1α release was calpain-dependent. These results show that UFP at very low concentrations are able to give rise to an inflammatory process that is responsible for IL-1α, IL-18 and IL-33 release, which is pronounced in PBMCs from smokers, confirming that these individuals are especially susceptible to inflammatory-based airway diseases once exposed to air pollution. PMID:28223692

  12. Comparison of carcinogen, carbon monoxide, and ultrafine particle emissions from narghile waterpipe and cigarette smoking: Sidestream smoke measurements and assessment of second-hand smoke emission factors

    NASA Astrophysics Data System (ADS)

    Daher, Nancy; Saleh, Rawad; Jaroudi, Ezzat; Sheheitli, Hiba; Badr, Thérèse; Sepetdjian, Elizabeth; Al Rashidi, Mariam; Saliba, Najat; Shihadeh, Alan

    2010-01-01

    The lack of scientific evidence on the constituents, properties, and health effects of second-hand waterpipe smoke has fueled controversy over whether public smoking bans should include the waterpipe. The purpose of this study was to investigate and compare emissions of ultrafine particles (UFP, <100 nm), carcinogenic polyaromatic hydrocarbons (PAH), volatile aldehydes, and carbon monoxide (CO) for cigarettes and narghile (shisha, hookah) waterpipes. These smoke constituents are associated with a variety of cancers, and heart and pulmonary diseases, and span the volatility range found in tobacco smoke. Sidestream cigarette and waterpipe smoke was captured and aged in a 1 m 3 Teflon-coated chamber operating at 1.5 air changes per hour (ACH). The chamber was characterized for particle mass and number surface deposition rates. UFP and CO concentrations were measured online using a fast particle spectrometer (TSI 3090 Engine Exhaust Particle Sizer), and an indoor air quality monitor. Particulate PAH and gaseous volatile aldehydes were captured on glass fiber filters and DNPH-coated SPE cartridges, respectively, and analyzed off-line using GC-MS and HPLC-MS. PAH compounds quantified were the 5- and 6-ring compounds of the EPA priority list. Measured aldehydes consisted of formaldehyde, acetaldehyde, acrolein, methacrolein, and propionaldehyde. We found that a single waterpipe use session emits in the sidestream smoke approximately four times the carcinogenic PAH, four times the volatile aldehydes, and 30 times the CO of a single cigarette. Accounting for exhaled mainstream smoke, and given a habitual smoker smoking rate of 2 cigarettes per hour, during a typical one-hour waterpipe use session a waterpipe smoker likely generates ambient carcinogens and toxicants equivalent to 2-10 cigarette smokers, depending on the compound in question. There is therefore good reason to include waterpipe tobacco smoking in public smoking bans.

  13. Size-Resolved Ultrafine Particle Deposition and Brownian Coagulation from Gasoline Vehicle Exhaust in an Environmental Test Chamber.

    PubMed

    Zhao, Yu; Wang, Fang; Zhao, Jianing

    2015-10-20

    Size-resolved deposition rates and Brownian coagulation of particles between 20 and 900 nm (mobility diameter) were estimated in a well-mixed environmental chamber from a gasoline vehicle exhaust with a total peak particle concentration of 10(5)-10(6) particles/cm(3) at 12.24-25.22 °C. A deposition theory with modified friction velocity and coagulation model was also employed to predict particle concentration decay. Initially during particle decay, approximately 85% or more of the particles had diameters of <100 nm. Particle deposition rates with standard deviations were highly dependent on particle size ranges, and varied from 0.012 ± 0.003 to 0.48 ± 0.02 h(-1). In the experiment, the friction velocity obtained was in the range 1.5-2.5 cm/s. The most explainable fractal dimension and Hamaker constant in coagulation model were 2.5-3 and 20 kT, respectively, and the contribution from coagulation dominated the total particle decay during the first 1 h of decay. It is considered that the modified friction velocity and best fitted fractal dimension and Hamaker constants could be further used to analyze gasoline vehicle exhaust particle dynamics and assess human exposure to vehicle particle pollutants in urban areas, tunnels, and underground parking lots.

  14. Ultrafine particles derived from mineral processing: A case study of the Pb-Zn sulfide ore with emphasis on lead-bearing colloids.

    PubMed

    Mikhlin, Yuri; Vorobyev, Sergey; Romanchenko, Alexander; Karasev, Sergey; Karacharov, Anton; Zharkov, Sergey

    2016-03-01

    Although mining and mineral processing industry is a vast source of heavy metal pollutants, the formation and behavior of micrometer- and nanometer-sized particles and their aqueous colloids entered the environment from the technological media has received insufficient attention to date. Here, the yield and characteristics of ultrafine mineral entities produced by routine grinding of the Pb-Zn sulfide ore (Gorevskoe ore deposit, Russia) were studied using laser diffraction analysis (LDA), dynamic light scattering (DLS) and zeta potential measurement, microscopy, X-ray photoelectron spectroscopy, with most attention given to toxic lead species. It was revealed, in particular, that the fraction of particles less that 1 μm in the ground ore typical reaches 0.4 vol. %. The aquatic particles in supernatants were micrometer size aggregates with increased content of zinc, sulfur, calcium as compared with the bulk ore concentrations. The hydrodynamic diameter of the colloidal species decreased with time, with their zeta potentials remaining about -12 mV. The colloids produced from galena were composed of 20-50 nm PbS nanoparticles associated with lead sulfate and thiosulfate, while the surface oxidation products at precipitated galena were largely lead oxyhydroxides. The size and zeta potential of the lead-bearing colloids decreased with time down to about 100 nm and from -15 mV to -30 mV, respectively. And, conversely, lead sulfide nanoparticles were mobilized before the aggregates during redispersion of the precipitates in fresh portions of water. The potential environmental impact of the metal-bearing colloids, which is due to the large-scale production and relative stability, is discussed.

  15. Health risks caused by short term exposure to ultrafine particles generated by residential wood combustion: a case study of Temuco, Chile.

    PubMed

    Díaz-Robles, Luis A; Fu, Joshua S; Vergara-Fernández, Alberto; Etcharren, Pablo; Schiappacasse, Luis N; Reed, Gregory D; Silva, María P

    2014-05-01

    Temuco is one of the most highly wood smoke polluted cities in Chile; however, there is scarce evidence of respiratory morbidity due to fine particulate matter. We aimed to estimate the relationship between daily concentration of ultrafine particles (UFP), with an aerodynamic diameter ≤ 0.1 μm, and outpatient visits for respiratory illness at medical care centers of Temuco, Chile, from August the 20th, 2009 to June the 30th, 2011. The Air Pollution Health Effects European Approach (APHEA2) protocol was followed, and a multivariate semi-parametric Poisson regression model was fitted with GAM techniques using R-Project statistical package; controlling for trend, seasonality, and confounders. The daily UFP were measured by a MOUDI NR-110 sampler. We found that results of the statistical analyses show significant associations between UFP and respiratory outpatient visits, with the elderly (population ≥ 65 years), being the group that presented the greatest risk. An interquartile increase of 4.73 μg/m(3) in UFP (lag 5 days) was associated with respiratory outpatient visits with a relative risk (RR) of 1.1458 [95% CI (1.0497-1.2507)] for the elderly. These results show novel findings regarding the relevance of daily UFP concentrations and health risk, especially for susceptible population in a wood smoke polluted city.

  16. Long-term observations of tropospheric particle number size distributions and equivalent black carbon mass concentrations in the German Ultrafine Aerosol Network (GUAN)

    NASA Astrophysics Data System (ADS)

    Birmili, Wolfram; Weinhold, Kay; Rasch, Fabian; Sonntag, André; Sun, Jia; Merkel, Maik; Wiedensohler, Alfred; Bastian, Susanne; Schladitz, Alexander; Löschau, Gunter; Cyrys, Josef; Pitz, Mike; Gu, Jianwei; Kusch, Thomas; Flentje, Harald; Quass, Ulrich; Kaminski, Heinz; Kuhlbusch, Thomas A. J.; Meinhardt, Frank; Schwerin, Andreas; Bath, Olaf; Ries, Ludwig; Gerwig, Holger; Wirtz, Klaus; Fiebig, Markus

    2016-08-01

    The German Ultrafine Aerosol Network (GUAN) is a cooperative atmospheric observation network, which aims at improving the scientific understanding of aerosol-related effects in the troposphere. The network addresses research questions dedicated to both climate- and health-related effects. GUAN's core activity has been the continuous collection of tropospheric particle number size distributions and black carbon mass concentrations at 17 observation sites in Germany. These sites cover various environmental settings including urban traffic, urban background, rural background, and Alpine mountains. In association with partner projects, GUAN has implemented a high degree of harmonisation of instrumentation, operating procedures, and data evaluation procedures. The quality of the measurement data is assured by laboratory intercomparisons as well as on-site comparisons with reference instruments. This paper describes the measurement sites, instrumentation, quality assurance, and data evaluation procedures in the network as well as the EBAS repository, where the data sets can be obtained (doi:10.5072/guan).

  17. Effect of Exposure to Atmospheric Ultrafine Particles on Production of Free Fatty Acids and Lipid Metabolites in the Mouse Small Intestine

    PubMed Central

    Li, Rongsong; Navab, Kaveh; Hough, Greg; Daher, Nancy; Zhang, Min; Mittelstein, David; Lee, Katherine; Pakbin, Payam; Saffari, Arian; Bhetraratana, May; Sulaiman, Dawoud; Beebe, Tyler; Wu, Lan; Jen, Nelson; Wine, Eytan; Tseng, Chi-Hong; Araujo, Jesus A.; Fogelman, Alan; Sioutas, Constantinos; Navab, Mohamed

    2014-01-01

    N, Wine E, Tseng CH, Araujo JA, Fogelman A, Sioutas C, Navab M, Hsiai TK. 2015. Effect of exposure to atmospheric ultrafine particles on production of free fatty acids and lipid metabolites in the mouse small intestine. Environ Health Perspect 123:34–41; http://dx.doi.org/10.1289/ehp.1307036 PMID:25170928

  18. Investigations of percutaneous uptake of ultrafine TiO 2 particles at the high energy ion nanoprobe LIPSION

    NASA Astrophysics Data System (ADS)

    Menzel, F.; Reinert, T.; Vogt, J.; Butz, T.

    2004-06-01

    Micronised TiO 2 particles with a diameter of about 15 nm are used in sunscreens as physical UV filter. Due to the small particle size it may be supposed that TiO 2 particles can pass through the uppermost horny skin layer ( stratum corneum) via intercellular channels and penetrate into deeper vital skin layers. Accumulations of TiO 2 particles in the skin can decrease the threshold for allergies of the immune system or cause allergic reactions directly. Spatially resolved ion beam analysis (PIXE, RBS, STIM and secondary electron imaging) was carried out on freeze-dried cross-sections of biopsies of pig skin, on which four different formulations containing TiO 2 particles were applied. The investigations were carried out at the high energy ion nanoprobe LIPSION in Leipzig with a 2.25 MeV proton beam, which was focused to a diameter of 1 μm. The analysis concentrated on the penetration depth and on pathways of the TiO 2 particles into the skin. In these measurements a penetration of TiO 2 particles through the s. corneum into the underlying stratum granulosum via intercellular space was found. Hair follicles do not seem to be important penetration pathways because no TiO 2 was detected inside. The TiO 2 particle concentration in the stratum spinosum was below the minimum detection limit of about 1 particle/μm 2. These findings show the importance of coating the TiO 2 particles in order to prevent damage of RNA and DNA of skin cells by photocatalytic reactions of the penetrated particles caused by absorption of UV light.

  19. Influence of ozone concentration and temperature on ultra-fine particle and gaseous volatile organic compound formations generated during the ozone-initiated reactions with emitted terpenes from a car air freshener.

    PubMed

    Lamorena, Rheo B; Lee, Woojin

    2008-10-30

    Experiments were conducted to identify the emissions from the car air freshener and to identify the formation of ultra-fine particles and secondary gaseous compounds during the ozone-initiated oxidations with emitted volatile organic compounds (VOCs). The identified primary constituents emitted from the car air freshener in this study were alpha-pinene, beta-pinene, p-cymene, and limonene. Formation of ultra-fine particles (4.4-160 nm) was observed when ozone was injected into the chamber containing emitted monoterpenes from the air freshener. Particle number concentrations, particle mass concentrations, and surface concentrations were measured in time dependent experiments to describe the particle formation and growth within the chamber. The irritating secondary gaseous products formed during the ozone-initiated reactions include formaldehyde, acetaldehyde, acrolein, acetone, and propionaldehyde. Ozone concentration (50 and 100 ppb) and temperature (30 and 40 degrees C) significantly affect the formation of particles and gaseous products during the ozone-initiated reactions. The results obtained in this study provided an insight on the potential exposure of particles and irritating secondary products formed during the ozone-initiated reaction to passengers in confined spaces.

  20. Ultrafine particles and associated pollutants on roadways and in community air of Los Angeles California, Beijing China, and the Los Angeles International Airport

    NASA Astrophysics Data System (ADS)

    Westerdahl, Frederick Dane

    Particles smaller than 10 microm in diameter are harmful to health. However, the smallest of these particles, ultrafine particles (UFP), equal to or smaller than 100 nm, may be especially harmful. Most are emitted by combustion sources, with transportation sources being a dominant contributor. While these particles have recently been under intense research, little is known regarding UFP concentrations or its components where people live, work, and commute. This dissertation reports on investigations of UFP and other pollutants in transportation-dominated areas. Included are findings from on-road, near-road and community monitoring studies performed in two megacities: Los Angeles, California and Beijing, China. A common feature of these studies was the application of advanced technologies to gather time-resolved measurements. An important finding made in Los Angeles was that real-time pollutant measurements could be made on busy roadways. UFP size distribution measurements made on a freeway with heavy-duty truck traffic demonstrated that UFP were much higher than on other highways or in community air. Nitric oxide (NO) levels were also much higher in these truck-dominated microenvironments. High correlations were found between UFP, black carbon (BC), particle counts, (NO), and particulate polycyclic aromatic hydrocarbons. Monitoring at Los Angeles International Airport demonstrated that aircraft are important sources of UFP. Elevated UFP counts were found 900 meters from a runway used for take offs, while smaller values were found 500 meters downwind of a runway used for landings. These measurements showed a persistence of UFP at the community boundary in excess of measurements from roadside studies. A peak UFP measurement of 4.8 million particles cm -3 was made approximately 75 meters from a jet aircraft waiting to takeoff. Measurements made in Beijing demonstrated that heavy-duty diesel truck activity severely impacts community air quality. Black carbon was a

  1. Clustering Dynamics of Ultra-fine Particulate Systems

    NASA Astrophysics Data System (ADS)

    Dutt, Meenakshi; Elliott, James

    2008-03-01

    Length scales of particles and their surrounding medium strongly determines the nature of their interactions with one another and their responses to external fields. We are interested in systems of ultrafine particles (0.1 - 1.0 micron) such as volcanic ash, solid aerosols, or fine powders for pharmaceutical ihalation applications. We develop a numerical model for these systems using the Derjaguin-Muller-Toporov (DMT) adhesion theory along with the van der Waals attraction between the particles and their contact mechanical interactions. We study the dynamics of these systems in the absence and presence of gravity by controlling the particle size, and thereby, the surface properties of the particles. The high surface energies of these particles causes them to agglomerate as they gravitationally settle. We explore their internal structure as a function of their particle size.

  2. Fine and ultrafine particles at a near-free tropospheric environment over the high-altitude station Hanle in the Trans-Himalaya: New particle formation and size distribution

    NASA Astrophysics Data System (ADS)

    Moorthy, K. Krishna; Sreekanth, V.; Prakash Chaubey, Jai; Gogoi, Mukunda M.; Suresh Babu, S.; Kumar Kompalli, Sobhan; Bagare, S. P.; Bhatt, Bhuvan C.; Gaur, Vinod K.; Prabhu, T. P.; Singh, N. S.

    2011-10-01

    Number-size distributions of ultrafine, fine, and accumulation mode aerosols in the size range 5-1300 nm have been measured regularly from the pristine, high-altitude (for 4520 m above mean sea level) station Hanle in the Trans-Himalaya during the summer and autumn (August-November) 2009. The total number concentration ranged from 80 to 8000 cm-3 with a mean value of 1150 cm-3. Examination of the temporal variations of the size distributions indicated that formation of new ultrafine particles from the precursor gases (probably transported from the valley regions) was highly probable during the forenoon hours of the day, especially during the summer when the insolation was abundant, the process becoming increasingly less efficient as the season progressed toward winter. The time of occurrence of maximum concentration was generally during the forenoon, a few hours after sunrise, and this time shifted to later parts of the day as the season progressed toward winter, probably associated with later sunrise and low solar elevations. The number-size distributions revealed two prominent modes: a nucleation mode with mode diameter at ˜16 nm and a consistent accumulation mode with the mode diameter ranging between 115 and 150 nm. Examining the temporal features with the air mass types, it was noticed that the number concentration increased, and the accumulation mode broadened when west Asian air mass prevailed. In summer (during August) the number concentrations tended to higher values associated with air mass from the Indian origin. The ratio of the Aitken to accumulation mode concentration indicated that the aerosol particles existing over the site are aged.

  3. Indoor/outdoor relationships of quasi-ultrafine, accumulation and coarse mode particles in school environments in Barcelona: chemical composition and sources

    NASA Astrophysics Data System (ADS)

    Viana, M.; Rivas, I.; Querol, X.; Alastuey, A.; Sunyer, J.; Álvarez-Pedrerol, M.; Bouso, L.; Sioutas, C.

    2013-12-01

    The mass concentration, chemical composition and sources of quasi-ultrafine (quasi-UFP, PM0.25), accumulation (PM0.25-2.5) and coarse mode (PM2.5-10) particles were determined in indoor and outdoor air at 39 schools in Barcelona (Spain). Quasi-UFP mass concentrations measured (25.6 μg m-3 outdoors, 23.4 μg m-3 indoors) are significantly higher than those reported in other studies, and characterised by higher carbonaceous and mineral matter contents and a lower proportion of secondary inorganic ions. Results suggest that quasi-UFPs in Barcelona are affected by local sources in the schools, mainly human activity (e.g. organic material from textiles, etc.; contributing 23-46% to total quasi-UFP mass) and playgrounds (in the form of mineral matter, contributing about 9% to the quasi-UFP mass). The particle size distribution of toxicologically relevant metals and major aerosol components was characterised, displaying bimodal size distributions for most elements and components, and a unimodal distribution for inorganic salts (ammonium nitrate and sulphate) and elemental carbon (EC). Regarding metals, Ni and Cr were partitioned mainly in quasi-UFPs and could thus be of interest for epidemiological studies, given their high redox properties. Children exposure to quasi-UFP mass and chemical species was assessed by comparing the concentrations measured at urban background and traffic areas schools. Finally, three main indoor sources across all size fractions were identified by assessing indoor/outdoor ratios (I/O) of PM species used as their tracers: human activity (organic material), cleaning products, paints and plastics (Cl- source), and a metallic mixed source (comprising combinations of Cu, Zn, Co, Cd, Pb, As, V and Cr).

  4. Effect of advanced aftertreatment for PM and NOx reduction on heavy-duty diesel engine ultrafine particle emissions.

    PubMed

    Herner, Jorn Dinh; Hu, Shaohua; Robertson, William H; Huai, Tao; Chang, M-C Oliver; Rieger, Paul; Ayala, Alberto

    2011-03-15

    Four heavy-duty and medium-duty diesel vehicles were tested in six different aftertreament configurations using a chassis dynamometer to characterize the occurrence of nucleation (the conversion of exhaust gases to particles upon dilution). The aftertreatment included four different diesel particulate filters and two selective catalytic reduction (SCR) devices. All DPFs reduced the emissions of solid particles by several orders of magnitude, but in certain cases the occurrence of a volatile nucleation mode could increase total particle number emissions. The occurrence of a nucleation mode could be predicted based on the level of catalyst in the aftertreatment, the prevailing temperature in the aftertreatment, and the age of the aftertreatment. The particles measured during nucleation had a high fraction of sulfate, up to 62% of reconstructed mass. Additionally the catalyst reduced the toxicity measured in chemical and cellular assays suggesting a pathway for an inverse correlation between particle number and toxicity. The results have implications for exposure to and toxicity of diesel PM.

  5. The Ultrafine Mineralogy of a Molten Interplanetary Dust Particle as an Example of the Quench Regime of Atmospheric Entry Heating

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1996-01-01

    Melting and degassing of interplanetary dust particle L2005B22 at approx. 1200 C was due to flash heating during atmospheric entry. Preservation of the porous particle texture supports rapid quenching from the peak heating temperature whereby olivine and pyroxene nanocrystals (3 nm-26 nm) show partial devitrification of the quenched melt at T approx. = 450 C - 740 C. The implied ultrahigh cooling rates are calculated at approx. 105 C/h-106 C/h, which is consistent with quench rates inferred from the temperature-time profiles based on atmospheric entry heating models. A vesicular rim on a nonstoichiometric relic forsterite grain in this particle represents either evaporative magnesium loss during flash heating or thermally annealed ion implantation texture.

  6. Seasonal variations of ultra-fine and submicron aerosols in Taipei, Taiwan: implications for particle formation processes in a subtropical urban area

    NASA Astrophysics Data System (ADS)

    Cheung, H. C.; Chou, C. C.-K.; Chen, M.-J.; Huang, W.-R.; Huang, S.-H.; Tsai, C.-Y.; Lee, C. S. L.

    2016-02-01

    The aim of this study is to investigate the seasonal variations in the physicochemical properties of atmospheric ultra-fine particles (UFPs, d ≤ 100 nm) and submicron particles (PM1, d ≤ 1 µm) in an east Asian urban area, which are hypothesized to be affected by the interchange of summer and winter monsoons. An observation experiment was conducted at TARO (Taipei Aerosol and Radiation Observatory), an urban aerosol station in Taipei, Taiwan, from October 2012 to August 2013. The measurements included the mass concentration and chemical composition of UFPs and PM1, as well as the particle number concentration (PNC) and the particle number size distribution (PSD) with size range of 4-736 nm. The results indicated that the mass concentration of PM1 was elevated during cold seasons with a peak level of 18.5 µg m-3 in spring, whereas the highest concentration of UFPs was measured in summertime with a mean of 1.64 µg m-3. Moreover, chemical analysis revealed that the UFPs and PM1 were characterized by distinct composition; UFPs were composed mostly of organics, whereas ammonium and sulfate were the major constituents of PM1. The seasonal median of total PNCs ranged from 13.9 × 103 cm-3 in autumn to 19.4 × 103 cm-3 in spring. Median concentrations for respective size distribution modes peaked in different seasons. The nucleation-mode PNC (N4 - 25) peaked at 11.6 × 103 cm-3 in winter, whereas the Aitken-mode (N25 - 100) and accumulation-mode (N100 - 736) PNC exhibited summer maxima at 6.0 × 103 and 3.1 × 103 cm-3, respectively. The change in PSD during summertime was attributed to the enhancement in the photochemical production of condensable organic matter that, in turn, contributed to the growth of aerosol particles in the atmosphere. In addition, clear photochemical production of particles was observed, mostly in the summer season, which was characterized by average particle growth and formation rates of 4.0 ± 1.1 nm h-1 and 1.4 ± 0.8 cm-3 s-1

  7. Particle Deposition in a Child Respiratory Tract Model: In Vivo Regional Deposition of Fine and Ultrafine Aerosols in Baboons

    PubMed Central

    Albuquerque-Silva, Iolanda; Vecellio, Laurent; Durand, Marc; Avet, John; Le Pennec, Déborah; de Monte, Michèle; Montharu, Jérôme; Diot, Patrice; Cottier, Michèle; Dubois, Francis; Pourchez, Jérémie

    2014-01-01

    To relate exposure to adverse health effects, it is necessary to know where particles in the submicron range deposit in the respiratory tract. The possibly higher vulnerability of children requires specific inhalation studies. However, radio-aerosol deposition experiments involving children are rare because of ethical restrictions related to radiation exposure. Thus, an in vivo study was conducted using three baboons as a child respiratory tract model to assess regional deposition patterns (thoracic region vs. extrathoracic region) of radioactive polydisperse aerosols ([d16–d84], equal to [0.15 µm–0.5 µm], [0.25 µm–1 µm], or [1 µm–9 µm]). Results clearly demonstrated that aerosol deposition within the thoracic region and the extrathoraic region varied substantially according to particle size. High deposition in the extrathoracic region was observed for the [1 µm–9 µm] aerosol (72%±17%). The [0.15 µm–0.5 µm] aerosol was associated almost exclusively with thoracic region deposition (84%±4%). Airborne particles in the range of [0.25 µm–1 µm] showed an intermediate deposition pattern, with 49%±8% in the extrathoracic region and 51%±8% in the thoracic region. Finally, comparison of baboon and human inhalation experiments for the [1 µm–9 µm] aerosol showed similar regional deposition, leading to the conclusion that regional deposition is species-independent for this airborne particle sizes. PMID:24787744

  8. Particle deposition in a child respiratory tract model: in vivo regional deposition of fine and ultrafine aerosols in baboons.

    PubMed

    Albuquerque-Silva, Iolanda; Vecellio, Laurent; Durand, Marc; Avet, John; Le Pennec, Déborah; de Monte, Michèle; Montharu, Jérôme; Diot, Patrice; Cottier, Michèle; Dubois, Francis; Pourchez, Jérémie

    2014-01-01

    To relate exposure to adverse health effects, it is necessary to know where particles in the submicron range deposit in the respiratory tract. The possibly higher vulnerability of children requires specific inhalation studies. However, radio-aerosol deposition experiments involving children are rare because of ethical restrictions related to radiation exposure. Thus, an in vivo study was conducted using three baboons as a child respiratory tract model to assess regional deposition patterns (thoracic region vs. extrathoracic region) of radioactive polydisperse aerosols ([d16-d84], equal to [0.15 µm-0.5 µm], [0.25 µm-1 µm], or [1 µm-9 µm]). Results clearly demonstrated that aerosol deposition within the thoracic region and the extrathoraic region varied substantially according to particle size. High deposition in the extrathoracic region was observed for the [1 µm-9 µm] aerosol (72% ± 17%). The [0.15 µm-0.5 µm] aerosol was associated almost exclusively with thoracic region deposition (84% ± 4%). Airborne particles in the range of [0.25 µm-1 µm] showed an intermediate deposition pattern, with 49% ± 8% in the extrathoracic region and 51% ± 8% in the thoracic region. Finally, comparison of baboon and human inhalation experiments for the [1 µm-9 µm] aerosol showed similar regional deposition, leading to the conclusion that regional deposition is species-independent for this airborne particle sizes.

  9. Experimental Study on Ultrafine Particle Removal Performance of Portable Air Cleaners with Different Filters in an Office Room

    PubMed Central

    Ma, Huan; Shen, Henggen; Shui, Tiantian; Li, Qing; Zhou, Liuke

    2016-01-01

    Size- and time-dependent aerodynamic behaviors of indoor particles, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different filters. In-situ real-time measurements were taken using an optical particle counter. The filtration characteristics of filter media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret filter (EE) medium shows better initial removal efficiency than the high efficiency (HE) medium in the 0.3–3.5 μm particle size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 104 m3/m2. The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC) with the pre-filter (PR) or the active carbon granule filter (CF) was relatively poor. While PAC with the pre-filter and the high efficiency filter (PR&HE) showed maximum single-pass efficiency for PM1.0 (88.6%), PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret filters augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized particles could be greater than for PACs without PR. Without regard to the lifetime, the electret filters performed better with respect to resource saving and purification improvement. A most penetrating particle size range (MPPS: 0.4–0.65 μm) exists in both HE and electret filters; the MPPS tends to become larger after HE and electret filters are combined with PR. These results serve to provide a better understanding of the indoor particle removal performance of PACs when combined with different kinds of filters in school

  10. Analysis of the chemical composition of ultrafine particles from two domestic solid biomass fired room heaters under simulated real-world use

    NASA Astrophysics Data System (ADS)

    Ozgen, Senem; Becagli, Silvia; Bernardoni, Vera; Caserini, Stefano; Caruso, Donatella; Corbella, Lorenza; Dell'Acqua, Manuela; Fermo, Paola; Gonzalez, Raquel; Lonati, Giovanni; Signorini, Stefano; Tardivo, Ruggero; Tosi, Elisa; Valli, Gianluigi; Vecchi, Roberta; Marinovich, Marina

    2017-02-01

    Two common types of wood (beech and fir) were burned in commercial pellet (11.1 kW) and wood (8.2 kW) stoves following a combustion cycle simulating the behavior of a real-world user. Ultrafine particulate matter (UFP, dp < 100 nm) was sampled with three parallel multistage impactors and analyzed for metals, main water soluble ions, anhydrosugars, total carbon, and PAH content. The measurement of the number concentration and size distribution was also performed by a fourth multistage impactor. UFP mass emission factors averaged to 424 mg/kgfuel for all the tested stove and wood type (fir, beech) combinations except for beech log burning in the wood stove (838 mg/kgfuel). Compositional differences were observed for pellets and wood UFP samples, where high TC levels characterize the wood log combustion and potassium salts are dominant in every pellet sample. Crucial aspects determining the UFP composition in the wood stove experiments are critical situations in terms of available oxygen (a lack or an excess of combustion air) and high temperatures. Whereas for the automatically controlled pellets stove local situations (e.g., hindered air-fuel mixing due to heaps of pellets on the burner pot) determine the emission levels and composition. Wood samples contain more potentially carcinogenic PAHs with respect to pellets samples. Some diagnostic ratios related to PAH isomers and anhydrosugars compiled from experimental UFP data in the present study and compared to literature values proposed for the emission source discrimination for atmospheric aerosol, extend the evaluation usually limited to higher particle size fractions also to UFP.

  11. A velocity map imaging photoelectron spectrometer for the study of ultrafine aerosols with a table-top VUV laser and Na-doping for particle sizing applied to dimethyl ether condensation.

    PubMed

    Yoder, Bruce L; West, Adam H C; Schläppi, Bernhard; Chasovskikh, Egor; Signorell, Ruth

    2013-01-28

    We present a new experimental configuration for the study of size-dependent, angle-resolved photoelectron and photoion spectra of weakly bound ultrafine aerosol particles targeted at particle sizes below ~20 nm. It combines single photon ionization by a tunable, table-top vacuum ultraviolet laser at energies up to 18 eV with velocity map imaging detection and independent size determination of the aerosol particles using the Na-doping method. As an example, the size-dependence of the valence photoelectron spectrum of dimethyl ether clusters and ultrafine aerosols is investigated. Up to a mean particle diameter of ~3-4 nm, the first ionization energy (value at band maximum) decreases systematically (up to ~1 eV) and the corresponding band broadens systematically (up to a factor of ~3) with increasing aggregate size. Plateau values for band positions and bandwidths are reached beyond a diameter of ~3-4 nm. Experimental evidence for the dominance of the fast intermolecular proton transfer over monomer fragmentation reactions upon ionization is presented via photoion imaging.

  12. Lung burden and deposition distribution of inhaled atmospheric urban ultrafine particles as the first step in their health risk assessment

    NASA Astrophysics Data System (ADS)

    Salma, Imre; Füri, Péter; Németh, Zoltán; Balásházy, Imre; Hofmann, Werner; Farkas, Árpád

    2015-03-01

    Realistic median particle number size distributions were derived by a differential mobility particle sizer in a diameter range of 6-1000 nm for near-city background, city centre, street canyon and road tunnel environments in Budapest. Deposition of inhaled particles within airway generations of an adult woman was determined by a stochastic lung deposition model for sleeping, sitting, light and heavy exercise breathing conditions. Deposition fractions in the respiratory tract were considerable and constant for all physical activities with a mean of 56%. Mean deposition fraction in the extra-thoracic region averaged for the urban environments was decreasing monotonically from 26% for sleeping to 9.4% for heavy exercise. The mean deposition fractions in the tracheobronchial region were constant for the physical activities and urban environments with an overall mean of 12.5%, while the mean deposition fraction in the acinar region averaged for the urban locations increased monotonically with physical activity from 14.7% for sleeping to 34% for heavy exercise. The largest contribution of the acinar deposition to the lung deposition was 75%. The deposition rates in the lung were larger than in the extra-thoracic region, and the deposition rate in the lung was increasingly realised in the AC region by physical activity. It was the extra-thoracic region that received the largest surface density deposition rates; its loading was higher by 3 orders of magnitude than for the lung. Deposition fractions in the airway generations exhibited a distinct peak in the acinar region. The maximum of the curves was shifted to peripheral airway generations with physical activity. The shapes of the surface density deposition rate curves were completely different from those for the deposition rates, indicating that the first few airway generations received the highest surface loading in the lung.

  13. Cellular uptake and toxic effects of fine and ultrafine metal-sulfate particles in human A549 lung epithelial cells.

    PubMed

    Könczöl, Mathias; Goldenberg, Ella; Ebeling, Sandra; Schäfer, Bianca; Garcia-Käufer, Manuel; Gminski, Richard; Grobéty, Bernard; Rothen-Rutishauser, Barbara; Merfort, Irmgard; Gieré, Reto; Mersch-Sundermann, Volker

    2012-12-17

    Ambient airborne particulate matter is known to cause various adverse health effects in humans. In a recent study on the environmental impacts of coal and tire combustion in a thermal power station, fine crystals of PbSO(4) (anglesite), ZnSO(4)·H(2)O (gunningite), and CaSO(4) (anhydrite) were identified in the stack emissions. Here, we have studied the toxic potential of these sulfate phases as particulates and their uptake in human alveolar epithelial cells (A549). Both PbSO(4) and CaSO(4) yielded no loss of cell viability, as determined by the WST-1 and NR assays. In contrast, a concentration-dependent increase in cytotoxicity was observed for Zn sulfate. For all analyzed sulfates, an increase in the production of reactive oxygen species (ROS), assessed by the DCFH-DA assay and EPR, was observed, although to a varying extent. Again, Zn sulfate was the most active compound. Genotoxicity assays revealed concentration-dependent DNA damage and induction of micronuclei for Zn sulfate and, to a lower extent, for CaSO(4), whereas only slight effects could be found for PbSO(4). Moreover, changes of the cell cycle were observed for Zn sulfate and PbSO(4). It could be shown further that Zn sulfate increased the nuclear factor kappa-B (NF-κB) DNA binding activity and activated JNK. During our TEM investigations, no effect on the appearance of the A549 cells exposed to CaSO(4) compared to the nonexposed cells was observed, and in our experiments, only one CaSO(4) particle was detected in the cytoplasm. In the case of exposure to Zn sulfate, no particles were found in the cytoplasm of A549 cells, but we observed a concentration-dependent increase in the number and size of dark vesicles (presumably zincosomes). After exposure to PbSO(4), the A549 cells contained isolated particles as well as agglomerates both in vesicles and in the cytoplasm. Since these metal-sulfate particles are emitted into the atmosphere via the flue gas of coal-fired power stations, they may be

  14. Differences in indoor versus outdoor concentrations of ultrafine particles, PM2.5, PMabsorbance and NO2 in Swiss homes.

    PubMed

    Meier, Reto; Eeftens, Marloes; Phuleria, Harish C; Ineichen, Alex; Corradi, Elisabetta; Davey, Mark; Fierz, Martin; Ducret-Stich, Regina E; Aguilera, Inmaculada; Schindler, Christian; Rochat, Thierry; Probst-Hensch, Nicole; Tsai, Ming-Yi; Künzli, Nino

    2015-01-01

    Indoor air quality is a growing concern as we spend the majority of time indoors and as new buildings are increasingly airtight for energy saving purposes. For a better understanding of residential indoor air pollution in Switzerland we conducted repeated 1-2-week-long indoor and outdoor measurements of particle number concentrations (PNC), particulate matter (PM), light absorbance of PM2.5 (PMabsorbance) and nitrogen dioxide (NO2). Residents of all homes were enrolled in the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA). Indoor levels were comparable in urban areas and generally low in rural homes. Average indoor levels were 7800 particles/cm(3) (interquartile range=7200); 8.7 μg/m(3) (6.5) PM2.5 and 10.2 μg/m(3) (11.2) NO2. All pollutants showed large variability of indoor/outdoor ratios between sites. We observed similar diurnal patterns for indoor and outdoor PNC. Nevertheless, the correlation of average indoor and outdoor PNC between sites as well as longitudinal indoor/outdoor correlations within sites were low. Our results show that a careful evaluation of home characteristics is needed when estimating indoor exposure to pollutants with outdoor origin.

  15. Development of porosity in an oxide dispersion strengthened ferritic alloy containing nanoscale oxide particles

    SciTech Connect

    Schneibel, Joachim H; Liu, Chain T; Hoelzer, David T; Mills, Michael J.; Sarosi, P. M.; Hayashi, Taisuke; Wendt, Ullrich; Heyse, Hartmut

    2007-01-01

    The development of porosity at 1000 C in an oxide dispersion strengthened ferritic alloy containing ultra-fine oxide particles with diameters on the order of a few nm is investigated. A comparison with an alloy fabricated by internal oxidation demonstrates that the porosity formation is associated with mechanical alloying with Y2O3 in argon. The pores grow in spite of a sub-micron grain size suggesting that the grain boundaries are not effective paths for removing entrapped gas from the pores.

  16. Ultrafine aerosol size distributions and sulfuric acid vapor pressures: Implications for new particle formation in the atmosphere. Year 2 progress report

    SciTech Connect

    McMurry, P.H.

    1993-07-01

    This project has two components: (1) measurement of H{sub 2}SO{sub 4} vapor pressures in air under temperature/relative humidity conditions similar to atmospheric, and (2) measurement of ultrafine aerosol size distributions. During Year 2, more effort was put on size distribution measurements. 4 figs.

  17. Ultrafine aerosol size distribution: A study of new particle formation in the atmosphere. Final report on DOE Grant number: DE-FG02-91ER61205

    SciTech Connect

    McMurry, Peter H.; Eisele, Fred

    1998-12-31

    This project involved studies pertinent to the formation of new particles by homogeneous nucleation in the atmosphere. The research focused on (1) the development of instrumentation to measure size distributions of freshly nucleated particles in the 3 to 10 nm diameter range, (2) laboratory studies of particle thermodynamic and transport properties relevant to nucleation in the atmosphere, and (3) field measurements of new particle formation by homogeneous nucleation. Highlights of the achievements under this grant are summarized briefly. A complete list of publications and presentations supported by the grant is given.

  18. Ultrafine particles from diesel vehicle emissions at different driving cycles induce differential vascular pro-inflammatory responses: Implication of chemical components and NF-κB signaling

    PubMed Central

    2010-01-01

    Background Epidemiological evidence supports the association between exposure to ambient particulate matter (PM) and cardiovascular diseases. Chronic exposure to ultrafine particles (UFP; Dp <100 nm) is reported to promote atherosclerosis in ApoE knockout mice. Atherogenesis-prone factors induce endothelial dysfunction that contributes to the initiation and progression of atherosclerosis. We previously demonstrated that UFP induced oxidative stress via c-Jun N-terminal Kinases (JNK) activation in endothelial cells. In this study, we investigated pro-inflammatory responses of human aortic endothelial cells (HAEC) exposed to UFP emitted from a diesel truck under an idling mode (UFP1) and an urban dynamometer driving schedule (UFP2), respectively. We hypothesize that UFP1 and UFP2 with distinct chemical compositions induce differential pro-inflammatory responses in endothelial cells. Results UFP2 contained a higher level of redox active organic compounds and metals on a per PM mass basis than UFP1. While both UFP1 and UFP2 induced superoxide production and up-regulated stress response genes such as heme oxygenease-1 (HO-1), OKL38, and tissue factor (TF), only UFP2 induced the expression of pro-inflammatory genes such as IL-8 (2.8 ± 0.3-fold), MCP-1 (3.9 ± 0.4-fold), and VCAM (6.5 ± 1.1-fold) (n = 3, P < 0.05). UFP2-exposed HAEC also bound to a higher number of monocytes than UFP1-exposed HAEC (Control = 70 ± 7.5, UFP1 = 106.7 ± 12.5, UFP2 = 137.0 ± 8.0, n = 3, P < 0.05). Adenovirus NF-κB Luciferase reporter assays revealed that UFP2, but not UFP1, significantly induced NF-κB activities. NF-κB inhibitor, CAY10512, significantly abrogated UFP2-induced pro-inflammatory gene expression and monocyte binding. Conclusion While UFP1 induced higher level of oxidative stress and stress response gene expression, only UFP2, with higher levels of redox active organic compounds and metals, induced pro-inflammatory responses via NF-κB signaling. Thus, UFP with distinct

  19. Development of manufacturing systems for nanocrystalline and ultra-fine grain materials employing indexing equal channel angular pressing

    NASA Astrophysics Data System (ADS)

    Hester, Michael Wayne

    Nanotechnology offers significant opportunities in providing solutions to existing engineering problems as well as breakthroughs in new fields of science and technology. In order to fully realize benefits from such initiatives, nanomanufacturing methods must be developed to integrate enabling constructs into commercial mainstream. Even though significant advances have been made, widespread industrialization in many areas remains limited. Manufacturing methods, therefore, must continually be developed to bridge gaps between nanoscience discovery and commercialization. A promising technology for integration of top-down nanomanufacturing yet to receive full industrialization is equal channel angular pressing, a process transforming metallic materials into nanostructured or ultra-fine grained materials with significantly improved performance characteristics. To bridge the gap between process potential and actual manufacturing output, a prototype top-down nanomanufacturing system identified as indexing equal channel angular pressing (IX-ECAP) was developed. The unit was designed to capitalize on opportunities of transforming spent or scrap engineering elements into key engineering commodities. A manufacturing system was constructed to impose severe plastic deformation via simple shear in an equal channel angular pressing die on 1100 and 4043 aluminum welding rods. 1/4 fraction factorial split-plot experiments assessed significance of five predictors on the response, microhardness, for the 4043 alloy. Predictor variables included temperature, number of passes, pressing speed, back pressure, and vibration. Main effects were studied employing a resolution III design. Multiple linear regression was used for model development. Initial studies were performed using continuous processing followed by contingency designs involving discrete variable length work pieces. IX-ECAP offered a viable solution in severe plastic deformation processing. Discrete variable length work piece

  20. Development of a 30-kW high temperature solar receiver using small particles as the heat exchanger

    NASA Astrophysics Data System (ADS)

    Hunt, A. J.; Deiringer, M.; Evans, D. B.; Hansen, L.; Hull, P. G.; Paydarfar, D.

    1982-09-01

    The purpose of this work is to develop a new type of solar thermal receiver that utilizes concentrated sunlight to heat a gas to high temperature to operate a turboelectric generator or to supply industrial process heat. The Small Particle Heat Exchange Receiver (SPHER) uses a very small mass of ultrafine carbon particles suspended in a gas to absorb sunlight and transfer the heat to the gas. The concentrated sunlight, provided by a parabolic dish or system of mirrors, passes through a window into a chamber containing the absorbing suspension. Because the energies are very small, they are not significantly affected by gravitational or inertial forces; they are effectively part of the gas.

  1. Coated particle waste form development

    SciTech Connect

    Oma, K.H.; Buckwalter, C.Q.; Chick, L.A.

    1981-12-01

    Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes.

  2. CFD development for macro particle simulations

    NASA Astrophysics Data System (ADS)

    Zhao, Xiang; Glenn, Chance; Xiao, Zhigang; Zhang, Sijun

    2014-05-01

    Numerous industrial operations involve fluid-particle systems, in which both phases display very complex behaviour. Some examples include fluidisation technology in catalytic reactors, pneumatic transportation of grain or powder materials, carbon nanotube alignment in the nano-devices and circuit integration and so on. In this paper, a macro particle method is developed to model the fluid-particle flows. The macro particle is formed by a collection of micro-sized particles so that the number of macro particles to be tracked is much less than the number of smaller particles. Unlike the calculations of instantaneous point variables of fluid phase with moving discrete boundaries of the smaller particles with direct numerical simulation, the boundary of each macro particle is just dealt with the blocked-off approach. On the other hand, the flow fields based on the present method is solved by original Navier-Stokes, rather than the modified ones based on the locally averaged theorem. The flow fields are solved on the length scale of computational cells, while the resolutions of solid particles are the size of macro particle, which is determined as needed in specific applications. The macro particle method is validated by several selected cases, which demonstrate that the macro particle method could accurately resolve fluid-particle systems in an efficient, robust and flexible fashion.

  3. Preferred Crystallographic Orientation Development in Nano/Ultrafine-Grained 316L Stainless Steel During Martensite to Austenite Reversion

    NASA Astrophysics Data System (ADS)

    Eskandari, M.; Mohtadi-Bonab, M. A.; Basu, R.; Nezakat, M.; Kermanpur, A.; Szpunar, J. A.; Nahar, S.; Baghpanah, A. H.

    2015-02-01

    The crystallographic orientation of cold-rolled 316L stainless steel is investigated during reversion of strain-induced ά-martensite to nano/ultrafine-grained austenite upon annealing at 750 °C for different holding times; 1, 5, 15, and 30 min. The texture of nanoscale reverted austenite reveals a Brass ({110}<112>) and a Goss ({110}<100>) textures after annealing for 1 min. No new texture component is appeared through the completion of martensite to austenite reversion for 5 min, but the intensity of Brass and Goss textures are increased. Further annealing for 30 min results in a stronger texture with higher intensity for Brass compared to Goss.

  4. Development of an Ultra-fine Coal Dewatering Technology and an Integrated Flotation-Dewatering System for Coal Preparation Plants

    SciTech Connect

    Wu Zhang; David Yang; Amar Amarnath; Iftikhar Huq; Scott O'Brien; Jim Williams

    2006-12-22

    The project proposal was approved for only the phase I period. The goal for this Phase I project was to develop an industrial model that can perform continuous and efficient dewatering of fine coal slurries of the previous flotation process to fine coal cake of {approx}15% water content from 50-70%. The feasibility of this model should be demonstrated experimentally using a lab scale setup. The Phase I project was originally for one year, from May 2005 to May 2006. With DOE approval, the project was extended to Dec. 2006 without additional cost from DOE to accomplish the work. Water has been used in mining for a number of purposes such as a carrier, washing liquid, dust-catching media, fire-retardation media, temperature-control media, and solvent. When coal is cleaned in wet-processing circuits, waste streams containing water, fine coal, and noncombustible particles (ash-forming minerals) are produced. In many coal preparation plants, the fine waste stream is fed into a series of selection processes where fine coal particles are recovered from the mixture to form diluted coal fine slurries. A dewatering process is then needed to reduce the water content to about 15%-20% so that the product is marketable. However, in the dewatering process currently used in coal preparation plants, coal fines smaller than 45 micrometers are lost, and in many other plants, coal fines up to 100 micrometers are also wasted. These not-recovered coal fines are mixed with water and mineral particles of the similar particle size range and discharged to impoundment. The wasted water from coal preparation plants containing unrecoverable coal fine and mineral particles are called tailings. With time the amount of wastewater accumulates occupying vast land space while it appears as threat to the environment. This project developed a special extruder and demonstrated its application in solid-liquid separation of coal slurry, tailings containing coal fines mostly less than 50 micron. The

  5. Relationship of pulmonary toxicity and carcinogenicity of fine and ultrafine granular dusts in a rat bioassay

    PubMed Central

    Kolling, Angelika; Ernst, Heinrich; Rittinghausen, Susanne; Heinrich, Uwe

    2011-01-01

    The current carcinogenicity study with female rats focused on the toxicity and carcinogenicity of intratracheally instilled fine and ultrafine granular dusts. The positive control, crystalline silica, elicited the greatest magnitude and progression of pulmonary inflammatory reactions, fibrosis and the highest incidence of primary lung tumors (39.6%). Addition of poly-2-vinylpyridine-N-oxide decreased inflammatory responses, fibrosis, and the incidence of pulmonary tumors induced by crystalline quartz to 21.4%. After repeated instillation of soluble, ultrafine amorphous silica (15 mg) a statistically significant tumor response (9.4%) was observed, although, the inflammatory response in the lung was not as persistently severe as in rats treated with carbon black. Instillation of ultrafine carbon black (5 mg) caused a lung tumor incidence of 15%. In contrast to a preceding study using a dose of 66 mg coal dust, lung tumors were not detected after exposure to the same coal dust at a dose of 10 mg in this study. Pulmonary inflammatory responses to coal dust were very low indicating a mechanistic threshold for the development of lung tumors connected with particle related chronic inflammation. The animals treated with ultrafine carbon black and ultrafine amorphous silica showed significantly more severe lesions in non-cancerous endpoints when compared to animals treated with fine coal dust. Furthermore, carbon black treated rats showed more severe non-cancerous lung lesions than amorphous silica treated rats. Our data show a relationship between tumor frequencies and increasing scores when using a qualitative scoring system for specific non-cancerous endpoints such as inflammation, fibrosis, epithelial hyperplasia, and squamous metaplasia. PMID:21819261

  6. ULTRAFINE ASH AEROSOLS FROM COAL COMBUSTION: CHARACTERIZATION AND HEALTH EFFECTS

    EPA Science Inventory

    Ultrafine coal fly ash particles, defined here as those with diameters less than 0.5 micrometer, typically comprise less than 1% of the total fly ash mass. These particles are formed almost exclusively through ash vaporization, nucleation, and coagulation/condensation mechanisms,...

  7. Initial study of dry ultrafine coal beneficiation utilizing triboelectric charging with subsequent electrostatic separation

    SciTech Connect

    Link, T.A.; Killmeyer, R.P.; Elstrodt, R.H.; Haden, N.H.

    1990-10-01

    A novel, dry process using electrostatics to beneficiate ultrafine coal is being developed by the Coal Preparation Division at the Pittsburgh Energy Technology Center. The historical concept of triboelectricity and its eventual use as a means of charging coal for electrostatic separation will be discussed. Test data from a first-generation and a second-generation Tribo-Electrostatic separator are presented showing the effects of feed particle size, separator voltage, solids concentration in air, and particle velocity on separation performance. 10 refs., 10 figs., 9 tabs.

  8. Microstructure Development and Lateral Distribution of Defects in Ultra-fine Grained Copper Prepared by High-pressure Torsion

    NASA Astrophysics Data System (ADS)

    Procházka, Ivan; Čížek, Jakub; Melikhova, Oksana; Barnovská, Zuzana; Janeček, Miloš; Srba, Ondřej; Kužel, Radomír; Dobatkin, Sergej V.

    A defect study of ultra-fine grained (UFG) Cu prepared by high-pressure torsion (HPT) will be reported. Conventional positron annihilation spectroscopy (PAS) including positron lifetime (PLT) and Doppler broadening (DB) techniques was employed as the main experimental tool. PAS was combined with transmission electron microscopy, X-ray diffraction and Vickers microhardness (HV) measurements. First, lattice defects introduced by HPT were characterized. A very high concentration of defects created during HPT deformation was observed and the two kinds of defects could be identified: dislocations and small vacancy clusters (microvoids). Further investigations were focused on (i) the radial distributions of defects and (ii) the evolution of microstructure during HPT processing. The results of the present study are consistent with an increase of shear strain from the sample centre toward its periphery. Extended lateral mapping of microstructure was performed using HV and DB techniques. The latter one reveals a significant non-uniformity of defect distribution which was less pronounced in the HV measurements.

  9. Ultrafine grinding of low-rank coal: Final report

    SciTech Connect

    Bouchillon, C.W.; Steele, W.G.

    1986-08-01

    A study of ultrafine grinding of low-rank coals in a fluid-energy mill was undertaken. This report presents the results of the Phase I effort which included a review of the literature on ultrafine grinding, a review of theories of grinding, a combined grinding and drying experiment on Martin Lake Texas lignite, an evaluation of the energy requirements for the process, and an evaluation of the properties of the products from the grinding tests. A sample of Martin Lake Texas lignite was obtained and a series of tests were conducted in a fluid-energy mill at the Ergon, Inc., Micro-Energy Division development facility at Vicksburg, MS. The grinding fluids used were air at 116 F and steam at 225, 310, 350, 400, and 488 F as measured in the mill. The products of these tests were analyzed for volatile mattr, ash, total moisture, equilibrium moisture, heating value, density distribution, aerodynamic particle size classification, angle of repose, porosity, density, and particle size distribution. ASTM test procedures were followed where applicable. Ultimate and ash mineral analyses were also conducted on the samples. Results of the various tests are presented in detail in the report. In general, the fluid energy mill was used succssfully in simultaneous grinding and drying of the lignite. Particle size reduction to less than 10 microns on a population basis was achieved. The equilibrium moisture of the samples decreased with increasing grinding fluid temperatures. Density distribution studies showed that a significant fraction of the ash appeared in the >1.6 specific gravity particles. The energy required for the grinding/drying process increased with increasing mill temperatures. 29 refs., 18 figs., 13 tabs.

  10. FDPS: Framework for Developing Particle Simulators

    NASA Astrophysics Data System (ADS)

    Iwasawa, Masaki; Tanikawa, Ataru; Hosono, Natsuki; Nitadori, Keigo; Muranushi, Takayuki; Makino, Junichiro

    2016-04-01

    FDPS provides the necessary functions for efficient parallel execution of particle-based simulations as templates independent of the data structure of particles and the functional form of the interaction. It is used to develop particle-based simulation programs for large-scale distributed-memory parallel supercomputers. FDPS includes templates for domain decomposition, redistribution of particles, and gathering of particle information for interaction calculation. It uses algorithms such as Barnes-Hut tree method for long-range interactions; methods to limit the calculation to neighbor particles are used for short-range interactions. FDPS reduces the time and effort necessary to write a simple, sequential and unoptimized program of O(N^2) calculation cost, and produces compiled programs that will run efficiently on large-scale parallel supercomputers.

  11. Real-world PM, NO x, CO, and ultrafine particle emission factors for military non-road heavy duty diesel vehicles

    NASA Astrophysics Data System (ADS)

    Zhu, Dongzi; Nussbaum, Nicholas J.; Kuhns, Hampden D.; Chang, M.-C. Oliver; Sodeman, David; Moosmüller, Hans; Watson, John G.

    2011-05-01

    Training on US military bases involves nonroad diesel vehicles with emissions that can affect base personnel, nearby communities, and attainment of air quality standards. Nonroad diesel engines contribute 44% of diesel PM and 12% of total NO x emissions from mobile sources nationwide. Although military sector fuel use accounts for only ≈0.4% of distillate fuel use in US, emissions factors measured for these engines improve the representation of the relatively small (as compared to onroad sources) database of nonroad emission factors. Heavy-duty multi-axle, all-wheel drive military trucks are not compatible with regular single-axle dynamometers and their emissions cannot be measured under standard laboratory conditions. We have developed a novel in-plume technique to measure in-use emissions from vehicles with elevated stack. Real-world gaseous and particulate matter (PM) emission factors (EFs) from ten 7-ton 6-wheel drive trucks and two 8-wheel drive heavy tactical Logistics Vehicle System (LVS) vehicles were measured using in-plume sampling. The EFs of these trucks are comparable to those of onroad trucks while the PM EFs of 2-stroke LVS are ≈10 times higher than those of onroad vehicles. Lower EC/PM ratio was observed for LVS compared with MTVR. PM number emission factors were 5.9 × 10 14 particles km -1 for the trucks and 2.5 × 10 16 particles km -1 for the LVSs, three orders of magnitude higher than the proposed European Union standard of 6 × 10 11 particles km -1. The EFs sampled can be extended to engines used in the broader nonroad sector including agriculture and mining and used as inputs to the NONROAD model.

  12. Flocculation, hydrophobic agglomeration and filtration of ultrafine coal

    NASA Astrophysics Data System (ADS)

    Yu, Zhimin

    In coal preparation plant circuits, fine coal particles are aggregated either by oil agglomeration or by flocculation. In a new hydrophobic agglomeration process, recently developed hydrophobic latices are utilized. While the selectivity of such aggregation processes determines the beneficiation results, the degree of aggregation has a strong effect on fine coal filtration. The aim of this research was to study the fundamentals and analyze the common grounds for these processes, including the potential effect of the coal surface properties. The selective flocculation tests, in which three types of coal, which differed widely in surface wettability, and three additives (hydrophobic latices, a semi-hydrophobic flocculant and a typical hydrophilic polyelectrolyte) were utilized, showed that coal wettability plays a very important role in selective flocculation. The abstraction of a hydrophobic latex on coal and silica revealed that the latex had a much higher affinity towards hydrophobic coal than to hydrophilic mineral matter. As a result, the UBC-1 hydrophobic latex flocculated only hydrophobic coal particles while the polyelectrolyte (PAM) flocculated all the tested coal samples and minerals, showing no selectivity in the fine coal beneficiation. The oil agglomeration was tested using kerosene emulsified with various surfactants (e.g. cationic, anionic and non-ionic). Surfactants enhance not only oil emulsification, hence reducing oil consumption (down to 0.25--0.5%), but also entirely change the electrokinetic properties of the droplets and affect the interaction energy between oil droplets and coal particles. Consequently, the results found in the course of the experimental work strongly indicate that even oxidized coals can be agglomerated if cationic surfactants are used to emulsify the oil. Oil agglomeration of the Ford-4 ultrafine coal showed that even at extremely low oil consumption (0.25 to 0.5%), a clean coal product with an ash content around 5% at over

  13. Heterogeneities in inflammatory and cytotoxic responses of RAW 264.7 macrophage cell line to urban air coarse, fine, and ultrafine particles from six European sampling campaigns

    SciTech Connect

    Jalava, P.I.; Salonen, R.O.; Pennanen, A.S.; Sillanpaa, M.; Halinen, A.I.; Happo, M.S.; Hillamo, R.; Brunekreef, B.; Katsouyanni, K.; Sunyer, J.; Hirvonen, M.R.

    2007-03-15

    We investigated the cytotoxic and inflammatory activities of size-segregated particulate samples (particulate matter, PM) from contrasting air pollution situations in Europe. Coarse (PM10-2.5), fine (PM2.5-0.2), and ultrafine (PM0.2) particulate samples were collected with a modified Harvard high-volume cascade impactor (HVCI). Mouse RAW 264.7 macrophages were exposed to the samples for 24 h. Selected inflammatory mediators, nitric oxide (NO) and cytokines (tumor necrosis factor alpha (TNF alpha), interleukin 6 (IL-6), macrophage inflammatory protein-2 (MIP-2)), were measured together with cytotoxicity (MTT test), and analysis of apoptosis and cell cycle (propidium iodide staining). The PM10-2.5 samples had a much higher inflammatory activity than the PM2.5-0.2 and PM0.2 samples, but the PM2.5-0.2 samples showed the largest differences in inflammatory activity, and the PM0.2 samples in cytotoxicity, between the sampling campaigns. The PM2.5-0.2 samples from traffic environments in springtime Barcelona and summertime Athens had the highest inflammatory activities, which may be related to the high photochemical activity in the atmosphere during the sampling campaigns. The PM0.2 sample from wintertime Prague with proven impacts from local coal and biomass combustion had very high cytotoxic and apoptotic activities and caused a distinct cell cycle arrest. Thus, particulate size, sources, and atmospheric transformation processes affect the toxicity profile of urban air particulate matter. These factors may explain some of the heterogeneity observed in particulate exposure-response relationships of human health effects in epidemiological studies.

  14. High-temperature LDV seed particle development

    NASA Technical Reports Server (NTRS)

    Frish, Michael B.; Pierce, Vicky G.

    1989-01-01

    The feasibility of developing a method for making monodisperse, unagglomerated spherical particles greater than 50 nm in diameter was demonstrated. Carbonaceous particles were made by pyrolyzing ethylene with a pulsed CO2 laser, thereby creating a non-equilibrium mixture of carbon, hydrogen, hydrocarbon vapors, and unpyrolyzed ethylene. Via a complex series of reactions, the carbon and hydrocarbon vapors quickly condensed into the spherical particles. By cooling and dispersing them in a supersonic expansion immediately after their creation, the hot newly-formed spheres were prevented from colliding and coalescing, thus preventing the problem of agglomeration which as plagued other investigators studying laser-simulated particle formation. The cold particles could be left suspended in the residual gases indefinitely without agglomerating. Their uniform sizes and unagglomerated nature were visualized by collecting the particles on filters that were subsequently examined using electron microscopy. It was found the mean particle size can be coarsely controlled by varying the initial ethylene pressure, and can be finely controlled by varying the fluence (energy/unit area) with which the laser irradiates the gas. The motivating application for this research was to manufacture particles that could be used as laser Doppler velocimetry (LDV) seeds in high-temperature high-speed flows. Though the particles made in this program will not evaporate until heated to about 3000 K, and thus could serve as LDV seeds in some applications, they are not ideal when the hot atmosphere is also oxidizing. In that situation, ceramic materials would be preferable. Research performed elsewhere has demonstrated that selected ceramic materials can be manufactured by laser pyrolysis of appropriate supply gases. It is anticipated that, when the same gases are used in conjunction with the rapid cooling technique, unagglomerated spherical ceramic particles can be made with little difficulty. Such

  15. Development of ultrafine multichannel microfluidic mixer for synthesis of bimetallic nanoclusters: catalytic application of highly monodisperse AuPd nanoclusters stabilized by poly(N-vinylpyrrolidone).

    PubMed

    Hayashi, Naoto; Sakai, Yuka; Tsunoyama, Hironori; Nakajima, Atsushi

    2014-09-02

    On account of their novel properties, bimetallic nanoparticles and nanoclusters (NCs) are strong potential candidates for optical, magnetic, and catalytic functional materials. These properties depend on the chemical composition and size (number of constituent atoms) of the NCs. Control of size, structure, and composition is particularly important for fabricating highly functional materials based on bimetallic NCs. Size- and structure-controlled synthesis of two-element alloys can reveal their intrinsic electronic synergistic effects. However, because synergistic enhancement of activity is strongly affected by composition as well as by size and structure, controlled synthesis is a challenging task, particularly in catalytic applications. To investigate catalytic synergistic effects, we have synthesized highly monodisperse, sub-2 nm, solid-solution AuPd NCs stabilized with poly(N-vinylpyrrolidone) (AuPd:PVP) using a newly developed ultrafine microfluidic mixing device with 15 μm wide multiple lamination channels. The synergistic enhancement for catalytic aerobic oxidation of benzyl alcohol exhibited a volcano-shaped trend, with a maximum at 20-65 at. % Pd. From X-ray photoelectron spectroscopic measurements, we confirmed that the enhanced activity originates from the enhanced electron density at the Au sites, donated by Pd sites.

  16. Health hazards of ultrafine metal and metal oxide powders

    NASA Technical Reports Server (NTRS)

    Boylen, G. W., Jr.; Chamberlin, R. I.; Viles, F. J.

    1969-01-01

    Study reveals that suggested threshold limit values are from two to fifty times lower than current recommended threshold limit values. Proposed safe limits of exposure to the ultrafine dusts are based on known toxic potential of various materials as determined in particle size ranges.

  17. EFFECT OF CENTRAL FANS AND IN-DUCT FILTERS ON DEPOSITION RATES OF ULTRAFINE AND FINE PARTICLES IN AN OCCUPIED TOWNHOUSE

    EPA Science Inventory

    Airborne particles are implicated in morbidity and mortality of certain high-risk subpopulations. Exposure to particles occurs mostly indoors, where a main removal mechanism is deposition to surfaces. Deposition can be affected by the use of forced- air circulation through duct...

  18. Preparation of ultrafine silica from potash feldspar using sodium carbonate roasting technology

    NASA Astrophysics Data System (ADS)

    Liu, Jia-nan; Shen, Xiao-yi; Wu, Yan; Zhang, Jun; Zhai, Yu-chun

    2016-08-01

    A novel process was developed for the preparation of ultrafine silica from potash feldspar. In the first step, potash feldspar was roasted with Na2CO3 and was followed by leaching using NaOH solution to increase the levels of potassium, sodium, and aluminum in the solid residue. The leaching solution was then carbonated to yield ultrafine silica. The optimized reaction conditions in the roasting process were as follows: an Na2CO3-to-potash feldspar molar ratio of 1.1, a reaction temperature of 875°C, and a reaction time of 1.5 h. Under these conditions, the extraction rate of SiO2 was 98.13%. The optimized carbonation conditions included a final solution pH value of 9.0, a temperature of 40°C, a CO2 flow rate of 6 mL/min, a stirring intensity of 600 r/min, and an ethanol-to-water volume ratio of 1:9. The precipitation rate and granularity of the SiO2 particles were 99.63% and 200 nm, respectively. We confirmed the quality of the obtained ultrafine silica by comparing the recorded indexes with those specified in Chinese National Standard GB 25576―2010.

  19. In-vehicle measurement of ultrafine particles on compressed natural gas, conventional diesel, and oxidation-catalyst diesel heavy-duty transit buses.

    PubMed

    Hammond, Davyda; Jones, Steven; Lalor, Melinda

    2007-02-01

    Many metropolitan transit authorities are considering upgrading transit bus fleets to decrease ambient criteria pollutant levels. Advancements in engine and fuel technology have lead to a generation of lower-emission buses in a variety of fuel types. Dynamometer tests show substantial reductions in particulate mass emissions for younger buses (<10 years) over older models, but particle number reduction has not been verified in the research. Recent studies suggest that particle number is a more important factor than particle mass in determining health effects. In-vehicle particle number concentration measurements on conventional diesel, oxidation-catalyst diesel and compressed natural gas transit buses are compared to estimate relative in-vehicle particulate exposures. Two primary consistencies are observed from the data: the CNG buses have average particle count concentrations near the average concentrations for the oxidation-catalyst diesel buses, and the conventional diesel buses have average particle count concentrations approximately three to four times greater than the CNG buses. Particle number concentrations are also noticeably affected by bus idling behavior and ventilation options, such as, window position and air conditioning.

  20. Investigation of oxidation process of mechanically activated ultrafine iron powders

    NASA Astrophysics Data System (ADS)

    Lysenko, E. N.; Nikolaev, E. V.; Vlasov, V. A.; Zhuravkov, S. P.

    2016-02-01

    The oxidation of mechanically activated ultrafine iron powders was studied using X- ray powder diffraction and thermogravimetric analyzes. The powders with average particles size of 100 nm were made by the electric explosion of wire, and were subjected to mechanical activation in planetary ball mill for 15 and 40 minutes. It was shown that a certain amount of FeO phase is formed during mechanical activation of ultrafine iron powders. According to thermogravimetric analysis, the oxidation process of non-milled ultrafine iron powders is a complex process and occurs in three stages. The preliminary mechanical activation of powders considerably changes the nature of the iron powders oxidation, leads to increasing in the temperature of oxidation onset and shifts the reaction to higher temperatures. For the milled powders, the oxidation is more simple process and occurs in a single step.

  1. Spatial and indoor/outdoor gradients in urban concentrations of ultrafine particles and PM2.5 mass and chemical components

    NASA Astrophysics Data System (ADS)

    Zauli Sajani, Stefano; Ricciardelli, Isabella; Trentini, Arianna; Bacco, Dimitri; Maccone, Claudio; Castellazzi, Silvia; Lauriola, Paolo; Poluzzi, Vanes; Harrison, Roy M.

    2015-02-01

    In order to investigate relationships between outdoor air pollution and concentrations indoors, a novel design of experiment has been conducted at two sites, one heavily trafficked and the other residential. The novel design aspect involves the introduction of air directly to the centre of an unoccupied room by use of a fan and duct giving a controlled air exchange rate and allowing an evaluation of particle losses purely due to uptake on indoor surfaces without the losses during penetration of the building envelope which affect most measurement programmes. The rooms were unoccupied and free of indoor sources, and consequently reductions in particle concentration were due to deposition processes within the room alone. Measurements were made of indoor and outdoor concentrations of PM2.5, major chemical components and particle number size distributions. Despite the absence of penetration losses, indoor to outdoor ratios were very similar to those in other studies showing that deposition to indoor surfaces is likely to be the major loss process for indoor air. The results demonstrated a dramatic loss of nitrate in the indoor atmosphere as well as a selective loss of particles in the size range below 50 nm, in comparison to coarser particles. Depletion of indoor particles was greater during a period of cold weather with higher outdoor concentrations probably due to an enhancement of semi-volatile materials in the outdoor particulate matter. Indoor/outdoor ratios for PM2.5 were generally higher at the trafficked site than the residential site, but for particle number were generally lower, reflecting the different chemical composition and size distributions of particles at the two sites.

  2. Respiratory Effects of Fine and Ultrafine Particles from Indoor Sources—A Randomized Sham-Controlled Exposure Study of Healthy Volunteers

    PubMed Central

    Soppa, Vanessa J.; Schins, Roel P. F.; Hennig, Frauke; Hellack, Bryan; Quass, Ulrich; Kaminski, Heinz; Kuhlbusch, Thomas A. J.; Hoffmann, Barbara; Weinmayr, Gudrun

    2014-01-01

    Particulate air pollution is linked to impaired respiratory health. We analyzed particle emissions from common indoor sources (candles burning (CB), toasting bread (TB), frying sausages (FS)) and lung function in 55 healthy volunteers (mean age 33.0 years) in a randomized cross-over controlled exposure study. Lung-deposited particle surface area concentration (PSC), size-specific particle number concentration (PNC) up to 10 µm, and particle mass concentration (PMC) of PM1, PM2.5 and PM10 were determined during exposure (2 h). FEV1, FVC and MEF25%–75% was measured before, 4 h and 24 h after exposure. Wilcoxon-rank sum tests (comparing exposure scenarios) and mixed linear regression using particle concentrations and adjusting for personal characteristics, travel time and transportation means before exposure sessions were performed. While no effect was seen comparing the exposure scenarios and in the unadjusted model, inverse associations were found for PMC from CB and FS in relation to FEV1 and MEF25%–75%. with a change in 10 µg/m3 in PM2.5 from CB being associated with a change in FEV1 of −19 mL (95%-confidence interval:−43; 5) after 4 h. PMC from TB and PNC of UFP were not associated with lung function changes, but PSC from CB was. Elevated indoor fine particles from certain sources may be associated with small decreases in lung function in healthy adults. PMID:25000149

  3. Ultrafine grinding using a fluidized bed opposed jet mill: effects of feed load and rotational speed of classifier wheel on particle shape.

    PubMed

    Chan, L W; Lee, C C; Heng, P W S

    2002-09-01

    Circularity, aspect ratio, modelx, and pellips were employed to study the effects of process parameters, namely varying feed loads and rotational speeds of the classifier wheel, of the fluidized bed opposed jet mill on the shape of the micronized particles produced. The Shapiro-Wilk statistical test showed that 80.0% of the shape distributions of the four descriptors were not normal. Therefore, the Kruskal-Wallis test, which is a nonparametric statistical test, was employed to analyze the data. Micronized particles were more spherical and less elongated, as indicated respectively by higher median circularity and lower median modelx values when compared to unmilled lactose. These descriptors were able to indicate that the particles had been micronized. When feed loads of 250 and 350 g were used, increasing the rotational speed of the classifier wheel was found to bring about a decrease in span values of all the shape descriptors, indicating that the micronized particles were more uniform in shape. Micronized particles produced had lower median aspect ratio values than the unmilled lactose, whereas a higher feed load of 450 g resulted in the production of micronized particles that were less uniform in shape and more elliptical in nature, as reflected by the lower median pellips values. A higher feed load of 450 g caused a high level of impingement of particles on to the rotating classifier wheel, causing decreased classifier wheel efficiency, and this resulted in a less well-controlled micronization process. Thus, aspect ratio and pellips were sensitive to the changes in performance of the classifier wheel. The four shape descriptors were proposed to be used collectively as indicators for the monitoring of the micronization process.

  4. Ionizer assisted air filtration for collection of submicron and ultrafine particles-evaluation of long-term performance and influencing factors.

    PubMed

    Shi, Bingbing; Ekberg, Lars

    2015-06-02

    Previous research has demonstrated that unipolar ionization can enhance the filter performance to collect airborne particles, aeroallergens, and airborne microorganisms, without affecting the filter pressure drop. However, there is a lack of research on the long-term system performance as well as the influence of environmental and operational parameters. In this paper, both field and laboratory tests were carried out to evaluate the long-term particle collection efficiency of a synthetic filter of class M6 with and without ionization. The effect of air velocity, temperature, relative humidity, and particle concentration were further investigated in laboratory tests. Results showed that ionization enhanced the filtration efficiency by 40%-units during most of the operation time. When the ionization system was managed by periodically switching the ionizer polarity, the filtration efficiency against PM0.3-0.5 was maintained above 50% during half a year. Furthermore, the pressure drop of the ionizer-assisted M6 filter was 25-30% lower than that of a filter of class F7. The evaluation of various influencing factors demonstrated that (1) air moisture reduced the increase of filtration efficiency; (2) higher upstream particle concentration and air velocity decreased the filtration efficiency; and (3) the air temperature had very limited effect on the filtration efficiency.

  5. Impact of primary and secondary organic sources on the oxidative potential of quasi-ultrafine particles (PM0.25) at three contrasting locations in the Los Angeles Basin

    NASA Astrophysics Data System (ADS)

    Saffari, Arian; Hasheminassab, Sina; Wang, Dongbin; Shafer, Martin M.; Schauer, James J.; Sioutas, Constantinos

    2015-11-01

    To investigate the changing contribution of primary and secondary sources on the oxidative potential of particulate matter (PM) in a real-world urban atmosphere, 7 sets of quasi-ultrafine particles (PM0.25) were collected at three contrasting locations in the Los Angeles Basin, California, USA. Samples were collected in the coastal area of Long Beach during the morning rush hour period, representing fresh primary emissions from nearby freeways and the LA port; in central Los Angeles during midday, representing a mixture of fresh primary emissions and early products of photochemical secondary organic aerosol (SOA) formation; and at a downwind site (Upland) during afternoon, when the impacts of photochemically aged secondary PM are significant. Chemical composition showed distinctive trends, with the lowest fraction of water soluble organic carbon (WSOC) and other organic tracers of SOA formation (e.g. organic acids) at Long Beach, and the lowest abundance of organic tracers of primary vehicular emissions (such as polycyclic aromatic hydrocarbons and hopanes) at Upland. A molecular marker-based chemical mass balance (MM-CMB) model indicated that 72% of the total organic carbon at Long Beach was comprised of primary vehicular sources (combined heavy duty and light duty vehicles), while the vehicular fraction was found to be 50% and 39% at Los Angeles and Upland, respectively. Regression analysis suggested that at Long Beach, the variation in oxidative potential of PM0.25 (quantified using a macrophage-based reactive oxygen species (ROS) assay) was mainly driven by mobile vehicular emissions and the water-insoluble fraction of the organic carbon. In contrast, at Upland, where photochemical processing and secondary aerosol formation was the highest, WSOC and secondary organics were the major drivers of the oxidative potential variation. The multivariate regression analysis also indicated that as much as 58% of the overall spatial and temporal variation in the oxidative

  6. Preparing ultrafine PbS powders from the scrap lead-acid battery by sulfurization and inert gas condensation

    NASA Astrophysics Data System (ADS)

    Xia, Huipeng; Zhan, Lu; Xie, Bing

    2017-02-01

    A novel method for preparing ultrafine PbS powders involving sulfurization combined with inert gas condensation is developed in this paper, which is applicable to recycle Pb from lead paste of spent lead-acid batteries. Initially, the effects of the evaporation and condensation temperature, the inert gas pressure, the condensation distance and substrate on the morphology of as-obtained PbS ultrafine particles are intensively investigated using sulfur powders and lead particles as reagents. Highly dispersed and homogeneous PbS nanoparticles can be prepared under the optimized conditions which are 1223 K heating temperature, 573 K condensation temperature, 100 Pa inert gas pressure and 60 cm condensation distance. Furthermore, this method is successfully applied to recycle Pb from the lead paste of spent lead acid battery to prepare PbS ultrafine powders. This work does not only provide the theoretical fundamental for PbS preparation, but also provides a novel and efficient method for recycling spent lead-acid battery with high added-value products.

  7. Utility of an alternative bicycle commute route of lower proximity to motorised traffic in decreasing exposure to ultra-fine particles, respiratory symptoms and airway inflammation – a structured exposure experiment

    PubMed Central

    2013-01-01

    Background Bicycle commuting in an urban environment of high air pollution is known to be a potential health risk, especially for susceptible individuals. While risk management strategies aimed to reduce exposure to motorised traffic emissions have been suggested, only limited studies have assessed the utility of such strategies in real-world circumstances. Objectives The potential to lower exposure to ultrafine particles (UFP; < 0.1 μm) during bicycle commuting by reducing proximity to motorised traffic was investigated with real-time air pollution and intermittent acute inflammatory measurements in healthy individuals using their typical higher proximity, and an alternative lower proximity, bicycle commute route. Methods Thirty-five healthy adults (mean ± SD: age = 39 ± 11 yr; 29% female) completed two return trips, one each in the condition of their typical route (HIGH) and a pre-determined alternative route of lower proximity to motorised traffic (LOW); proximity being determined by the proportion of on-road cycle paths. Particle number concentration (PNC) and diameter (PD) were monitored in-commute in real-time. Acute inflammatory indices of respiratory symptoms (as a scalar of frequency from very low to very high / 1 to 5), lung function and spontaneous sputum (for inflammatory cell analyses) were collected immediately pre-commute, and immediately and three hours post-commute. Results In the condition of LOW, compared to in the condition of HIGH, there was a significant decrease in mean PNC (1.91 x e4 ± 0.93 × e4 ppcc vs. 2.95 × e4 ± 1.50 × e4 ppcc; p ≤ 0.001), and the mean frequency of in-commute offensive odour detection (2.1 vs. 2.8; p = 0.019), dust and soot observation (1.7 vs. 2.3; p = 0.038) and nasopharyngeal irritation (1.5 vs. 1.9; p = 0.007). There were no significant differences between LOW and HIGH in the commute distance and duration (12.8 ± 7.1 vs. 12.0 ± 6.9 km and 44 ± 17 vs. 42 ± 17 min, respectively), or other indices of

  8. Particle Detectors: Research and Development at CERN

    SciTech Connect

    Fabjan, C. W.

    2008-04-21

    Over the past 15 years a worldwide Detector R and D Programme has made the LHC experiments possible. These experiments operate at a new level of event rate and detection capabilities. Based on these advances, Detector R and D is continuing at CERN in close collaboration with University and Research Institutes. Several main directions are being pursued for solid-state and gaseous tracking devices, advanced crystal and noble liquid calorimetry, particle identification methods, and advanced signal-processing techniques. This effort is directed towards experiments at even higher collision rates at the LHC, the requirements for the next generation of linear electron-positron colliders and for applications outside particle physics, such as medical diagnostics instrumentation. We shall illustrate this challenging, stimulating and creative programme with examples and show how these developments are taking place in close collaboration between CERN and institutions around the globe.

  9. Experimental and modelling study of the plasma vapour-phase synthesis of ultrafine aluminum nitride powders

    NASA Astrophysics Data System (ADS)

    da Cruz, Antonio-Carlos

    An experimental and theoretical study of the fundamentals of the vapour phase synthesis of ultrafine aluminum nitride (AIN) particles using thermal plasma was carried out. The study used the concept of a transferred-arc reactor which produces AlN ultrafine powders in two stages: evaporation of aluminum (Al) metal by the transferred-arc in non nitriding conditions; and the reaction between Al vapour and ammonia (NH3) in a separate tubular reactor. A new version of this reactor concept was built in which the transferred-arc chamber and tubular reactor were vertically aligned. This reactor design allowed the study of both radial and axial mixing of ammonia with the plasma chamber off-gas. Ultrafine powders with a specific surface area (SSA) in the range of 38--270 m2/g were produced in two plasma chamber off-gas temperature levels (1800 and 2000 K), with different quenching intensities, and two different plasma gas compositions (pure Ar and Ar/H2 mixture). The dependence of the particle size and composition on the reactor operating conditions was investigated. Depending on the plasma gas composition, two different trends were observed for the SSA as a function of quenching intensity, with the radial injection of NH3. A two-dimensional numerical model was developed for the nucleation and growth of ultrafine particles in this system, using the method of moments. A new equation for the nucleation rate for the AlN system was developed. This equation considers the effect of reaction on the surface of clusters of the new phase. This new modelling approach could explain the trends observed experimentally. The importance of the mechanisms for the gas-to-condensed phase transition in the AlN system were examined. The sinterability of the powder produced was examined. Sintering to full density was achieved at 1550°C. Because of the high oxygen content of the powder, a second phase identified as aluminum oxynitride (ALON) was observed to form.

  10. Direct Quantification of Rare Earth Elements Concentrations in Urine of Workers Manufacturing Cerium, Lanthanum Oxide Ultrafine and Nanoparticles by a Developed and Validated ICP-MS.

    PubMed

    Li, Yan; Yu, Hua; Zheng, Siqian; Miao, Yang; Yin, Shi; Li, Peng; Bian, Ying

    2016-03-22

    Rare earth elements (REEs) have undergone a steady spread in several industrial, agriculture and medical applications. With the aim of exploring a sensitive and reliable indicator of estimating exposure level to REEs, a simple, accurate and specific ICP-MS method for simultaneous direct quantification of 15 REEs ((89)Y, (139)La, (140)Ce, (141)Pr, (146)Nd, (147)Sm, (153)Eu, (157)Gd, (159)Tb, (163)Dy, (165)Ho, (166)Er, (169)Tm, (172)Yb and (175)Lu) in human urine has been developed and validated. The method showed good linearity for all REEs in human urine in the concentrations ranging from 0.001-1.000 μg ∙ L(-1) with r² > 0.997. The limits of detection and quantification for this method were in the range of 0.009-0.010 μg ∙ L(-1) and 0.029-0.037 μg ∙ L(-1), the recoveries on spiked samples of the 15 REEs ranged from 93.3% to 103.0% and the relative percentage differences were less than 6.2% in duplicate samples, and the intra- and inter-day variations of the analysis were less than 1.28% and less than 0.85% for all REEs, respectively. The developed method was successfully applied to the determination of 15 REEs in 31 urine samples obtained from the control subjects and the workers engaged in work with manufacturing of ultrafine and nanoparticles containing cerium and lanthanum oxide. The results suggested that only the urinary levels of La (1.234 ± 0.626 μg ∙ L(-1)), Ce (1.492 ± 0.995 μg ∙ L(-1)), Nd (0.014 ± 0.009 μg ∙ L(-1)) and Gd (0.023 ± 0.010 μg ∙ L(-1)) among the exposed workers were significantly higher (p < 0.05) than the levels measured in the control subjects. From these, La and Ce were the primary components, and accounted for 88% of the total REEs. Lanthanum comprised 27% of the total REEs while Ce made up the majority of REE content at 61%. The remaining elements only made up 1% each, with the exception of Dy which was not detected. Comparison with the previously published data, the levels of urinary La and Ce in workers and

  11. Direct Quantification of Rare Earth Elements Concentrations in Urine of Workers Manufacturing Cerium, Lanthanum Oxide Ultrafine and Nanoparticles by a Developed and Validated ICP-MS

    PubMed Central

    Li, Yan; Yu, Hua; Zheng, Siqian; Miao, Yang; Yin, Shi; Li, Peng; Bian, Ying

    2016-01-01

    Rare earth elements (REEs) have undergone a steady spread in several industrial, agriculture and medical applications. With the aim of exploring a sensitive and reliable indicator of estimating exposure level to REEs, a simple, accurate and specific ICP-MS method for simultaneous direct quantification of 15 REEs (89Y, 139La, 140Ce, 141Pr, 146Nd, 147Sm, 153Eu, 157Gd, 159Tb, 163Dy, 165Ho, 166Er, 169Tm, 172Yb and 175Lu) in human urine has been developed and validated. The method showed good linearity for all REEs in human urine in the concentrations ranging from 0.001–1.000 μg∙L−1 with r2 > 0.997. The limits of detection and quantification for this method were in the range of 0.009–0.010 μg∙L−1 and 0.029–0.037 μg∙L−1, the recoveries on spiked samples of the 15 REEs ranged from 93.3% to 103.0% and the relative percentage differences were less than 6.2% in duplicate samples, and the intra- and inter-day variations of the analysis were less than 1.28% and less than 0.85% for all REEs, respectively. The developed method was successfully applied to the determination of 15 REEs in 31 urine samples obtained from the control subjects and the workers engaged in work with manufacturing of ultrafine and nanoparticles containing cerium and lanthanum oxide. The results suggested that only the urinary levels of La (1.234 ± 0.626 μg∙L−1), Ce (1.492 ± 0.995 μg∙L−1), Nd (0.014 ± 0.009 μg∙L−1) and Gd (0.023 ± 0.010 μg∙L−1) among the exposed workers were significantly higher (p < 0.05) than the levels measured in the control subjects. From these, La and Ce were the primary components, and accounted for 88% of the total REEs. Lanthanum comprised 27% of the total REEs while Ce made up the majority of REE content at 61%. The remaining elements only made up 1% each, with the exception of Dy which was not detected. Comparison with the previously published data, the levels of urinary La and Ce in workers and the control subjects show a higher trend

  12. Personal exposure to ultrafine particles: Two-level statistical modeling of background exposure and time-activity patterns during three seasons.

    PubMed

    Deffner, Veronika; Küchenhoff, Helmut; Maier, Verena; Pitz, Mike; Cyrys, Josef; Breitner, Susanne; Schneider, Alexandra; Gu, Jianwei; Geruschkat, Uta; Peters, Annette

    2016-01-01

    Personal exposure to air pollution is associated with time- and location-specific factors including indoor and outdoor air pollution, meteorology and time activities. Our investigation aims at the description and identification of factors determining personal exposure to particle number concentration (PNC) in everyday situations. Ten volunteers recorded their personal exposure to PNC and kept an activity diary in three different seasons besides stationary measurements of ambient air pollution and meteorology. Background exposure to PNC was modelled using the most predictive variables. In a second step, the effects of the activities were calculated adjusted for the background exposure. The average personal PNC level was highest in winter and was three times higher than the mean stationary PNC level while staying indoors and two times higher while staying outdoors. Personal indoor PNC levels were significantly increased during the use of candles, cooking and the occurrence of smell of food. High stationary outdoor PNC levels and low dew point temperatures were associated with increased personal outdoor PNC levels. Times spent in public transport were associated with lower personal PNC levels than other times spent in transportation. Personal PNC levels in everyday situations exhibited a large variability because of seasonal, microenvironment-specific and activity-specific influences.

  13. VERSATILE AEROSOL CONCENTRATION ENRICHMENT SYSTEM (VACES) FOR SIMULTANEOUS IN VIVO AND IN VITRO EVALUATION OF TOXIC EFFECTS OF ULTRAFINE, FINE AND COARSE AMBIENT PARTICLES. PART II: FIELD EVALUATION. (R827352C001)

    EPA Science Inventory

    This study presents results from a field evaluation of a mobile versatile aerosol concentration enrichment system (VACES), designed to enhance the ambient concentrations of ultrafine (less than 0.18 small m...</p>
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      <li>
      <p><a target=VERSATILE AEROSOL CONCENTRATION ENRICHMENT SYSTEM (VACES) FOR SIMULTANEOUS IN-VIVO AND IN-VITRO EVALUATION OF TOXIC EFFECTS OF ULTRAFINE, FINE, AND COARSE AMBIENT PARTICLES. PART II. FIELD EVALUATION. (R826232)

    EPA Science Inventory

    Abstract

    This study presents results from a field evaluation of a mobile versatile aerosol concentration enrichment system (VACES), designed to enhance the ambient concentrations of ultrafine (less than 0.18 In-situ loading ultrafine AuPd particles on ceria: highly active catalyst for solvent-free selective oxidation of benzyl alcohol.

    PubMed

    Zhang, Hongye; Xie, Yun; Sun, Zhenyu; Tao, Ranting; Huang, Changliang; Zhao, Yanfei; Liu, Zhimin

    2011-02-01

    Ce(III) oxide was synthesized under the protection of nitrogen gas, which had strong ability to reduce noble metal ions (e.g., Au, Pd ions) into metallic forms under oxygen-free conditions. On the basis of the surface redox reaction between the Ce(III) oxide support and noble metal ions, an effective and novel approach was presented to prepare noble metal/CeO(2) nanocatalysts, and a series of AuPd/CeO(2) nanocomposites with different Au:Pd molar ratios and metal loadings were obtained in the absence of any extra reducing and protective agents. The resultant composites were characterized by different techniques including X-ray diffraction, transmission electron microspectroscopy, X-ray photoelectron microspectroscopy, and ICP-AES analysis. It was demonstrated that in the AuPd/CeO(2) composites the content of Ce(III) reached about 30%, and the AuPd bimetallic particles with average size of 2.6 or 3.3 nm and narrow size distribution were uniformly distributed on the CeO(2) nanorods. The AuPd/CeO(2) composites were found to be excellent heterogeneous nanocatalysts for the selective oxidation of benzyl alcohol under solvent-free conditions. It was shown that all the AuPd/CeO(2) catalysts exhibited good selectivity toward benzaldehyde; especially, the catalyst with Au:Pd = 1:5 and metal loading of 1.2 wt % displayed extremely high activity with a TOF = 30.1 s(-1) at 160 °C.

  14. Development of Quality Control Parameters and Electronic Data Recording for an Ambient Air Particle Inhalation Exposure System

    EPA Science Inventory

    Ambient air particle concentrating systems were installed by the US EPA in RTP, NC. These systems, designed by Harvard School of Public Health’s Department of Environmental Sciences and Engineering (Boston, MA), concentrated ambient fine and ultra-fine mode particulate matter (P...

  15. A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials.

    PubMed

    Xiu, Fu-Rong; Weng, Huiwei; Qi, Yingying; Yu, Gending; Zhang, Zhigang; Zhang, Fu-Shen; Chen, Mengjun

    2017-02-01

    In this study, supercritical methanol (SCM) process was successfully used for the preparation of ultrafine copper materials from waste printed circuit boards (PCBs) after nitric acid pretreatment. Waste PCBs were pretreated twice in nitric acid. Sn and Pb were recovered by the first nitric acid pretreatment. The leach liquor with a high concentration of copper ions after the second nitric acid leaching was subjected to SCM process. The mixture of Cu and Cu2O with poor uniformity of particle size was formed due to the effect of ferric iron contained in the leach liquor of waste PCBs, while more uniform and spherical Cu particles with high monodispersity and smaller size could be prepared after the removal of Fe. The size of Cu particles increased obviously with the decline of SCM temperature, and particles became highly aggregated when the reaction temperature decreased to 300°C. The size of Cu particles decreased markedly with the decrease of initial concentration of copper ion in the leach liquor of waste PCBs. It is believed that the process developed in this study is simple and practical for the preparation of ultrafine copper materials from waste PCBs with the aim of recycling these waste resources as a high value-added product.

  16. Protective effects of pulmonary epithelial lining fluid on oxidative stress and DNA single-strand breaks caused by ultrafine carbon black, ferrous sulphate and organic extract of diesel exhaust particles

    SciTech Connect

    Chuang, Hsiao-Chi; Cheng, Yi-Ling; Lei, Yu-Chen; Chang, Hui-Hsien; Cheng, Tsun-Jen

    2013-02-01

    Pulmonary epithelial lining fluid (ELF) is the first substance to make contact with inhaled particulate matter (PM) and interacts chemically with PM components. The objective of this study was to determine the role of ELF in oxidative stress, DNA damage and the production of proinflammatory cytokines following physicochemical exposure to PM. Ultrafine carbon black (ufCB, 15 nm; a model carbonaceous core), ferrous sulphate (FeSO{sub 4}; a model transition metal) and a diesel exhaust particle (DEP) extract (a model organic compound) were used to examine the acellular oxidative potential of synthetic ELF and non-ELF systems. We compared the effects of exposure to ufCB, FeSO{sub 4} and DEP extract on human alveolar epithelial Type II (A549) cells to determine the levels of oxidative stress, DNA single-strand breaks and interleukin-8 (IL-8) production in ELF and non-ELF systems. The effects of ufCB and FeSO{sub 4} on the acellular oxidative potential, cellular oxidative stress and DNA single-strand breakage were mitigated significantly by the addition of ELF, whereas there was no decrease following treatment with the DEP extract. There was no significant effect on IL-8 production following exposure to samples that were suspended in ELF/non-ELF systems. The results of the present study indicate that ELF plays an important role in the initial defence against PM in the pulmonary environment. Experimental components, such as ufCB and FeSO{sub 4}, induced the production of oxidative stress and led to DNA single-strand breaks, which were moderately prevented by the addition of ELF. These findings suggest that ELF plays a protective role against PM-driven oxidative stress and DNA damage. -- Highlights: ► To determine the role of ELF in ROS, DNA damage and IL-8 after exposure to PM. ► ufCB, FeSO{sub 4} and DEP extract were used to examine the protective effects of ELF. ► PM-driven oxidative stress and DNA single-strand breakage were mitigated by ELF. ► The findings

  17. Preservation of amorphous ultrafine material: A proposed proxy for slip during recent earthquakes on active faults

    NASA Astrophysics Data System (ADS)

    Hirono, Tetsuro; Asayama, Satoru; Kaneki, Shunya; Ito, Akihiro

    2016-11-01

    The criteria for designating an “Active Fault” not only are important for understanding regional tectonics, but also are a paramount issue for assessing the earthquake risk of faults that are near important structures such as nuclear power plants. Here we propose a proxy, based on the preservation of amorphous ultrafine particles, to assess fault activity within the last millennium. X-ray diffraction data and electron microscope observations of samples from an active fault demonstrated the preservation of large amounts of amorphous ultrafine particles in two slip zones that last ruptured in 1596 and 1999, respectively. A chemical kinetic evaluation of the dissolution process indicated that such particles could survive for centuries, which is consistent with the observations. Thus, preservation of amorphous ultrafine particles in a fault may be valuable for assessing the fault’s latest activity, aiding efforts to evaluate faults that may damage critical facilities in tectonically active zones.

  18. Preservation of amorphous ultrafine material: A proposed proxy for slip during recent earthquakes on active faults

    PubMed Central

    Hirono, Tetsuro; Asayama, Satoru; Kaneki, Shunya; Ito, Akihiro

    2016-01-01

    The criteria for designating an “Active Fault” not only are important for understanding regional tectonics, but also are a paramount issue for assessing the earthquake risk of faults that are near important structures such as nuclear power plants. Here we propose a proxy, based on the preservation of amorphous ultrafine particles, to assess fault activity within the last millennium. X-ray diffraction data and electron microscope observations of samples from an active fault demonstrated the preservation of large amounts of amorphous ultrafine particles in two slip zones that last ruptured in 1596 and 1999, respectively. A chemical kinetic evaluation of the dissolution process indicated that such particles could survive for centuries, which is consistent with the observations. Thus, preservation of amorphous ultrafine particles in a fault may be valuable for assessing the fault’s latest activity, aiding efforts to evaluate faults that may damage critical facilities in tectonically active zones. PMID:27827413

  1. Effect of surface moisture on dielectric behavior of ultrafine BaTiO3 particulates.

    NASA Technical Reports Server (NTRS)

    Mountvala, A. J.

    1971-01-01

    The effects of adsorbed H2O on the dielectric properties of ultrafine BaTiO3 particulates of varying particle size and environmental history were determined. The dielectric behavior depends strongly on surface hydration. No particle size dependence of dielectric constant was found for dehydroxylated surfaces in ultrafine particulate (unsintered) BaTiO3 materials. For equivalent particle sizes, the ac conductivity is sensitive to surface morphology. Reactions with H2O vapor appear to account for the variations in dielectric properties. Surface dehydration was effectively accomplished by washing as-received powders in isopropanol.

  2. Size distributions of fine and ultrafine particles in the city of Strasbourg: correlation between number of particles and concentrations of NO(x) and SO(2) gases and some soluble ions concentration determination.

    PubMed

    Roth, Estelle; Kehrli, Damaris; Bonnot, Karine; Trouvé, Gwénaëlle

    2008-01-01

    An Electrical Low Pressure Impactor (ELPI) was used during spring and autumn 2003 in the centre of Strasbourg for the measurement of atmospheric aerosols size distribution. The concentration of NO(x) and SO(2) in air was simultaneously measured with specific analysers. Samples were collected in the range 0.007-10 microm in equivalent aerodynamic diameter size. Number distributions are representative of a pollution originating from urban traffic with a particle size distribution exhibiting a nucleation mode below 29 nm and an accumulation mode around 80 nm in size. A mean particle density equal to 39000+/-35000 total particles per cm(3) with a size ranging from 7 to 10 microm was obtained after a sampling period of 2 weeks in spring. About 86.9% of the number of particles have an aerodynamic diameter below 0.1 microm and 13.1% between 0.1 and 1 microm. Correlation coefficients between the number of particles impacted on each ELPI plate and gas concentrations (SO(2) and NO(x)) showed that the numbers of particles with diameter between 0.10 and 0.62 microm are highly related to the NO(x) concentration. This result indicates that particles are traffic induced since NO(x) is mainly emitted by cars as shown by measurements on various sites. Particles are less clearly correlated to the SO(2) concentration. Particle analysis on different ELPI plates for a sampling period of 2 weeks in autumn showed high level of soluble NO(3)(-), SO(4)(2-) and NH(4)(+) ions. Indeed, up to 90% b.w. of these three species were found in the particle range 0.1-1 microm. The formation of particulate NH(4)NO(3) is favoured by high NO(x) concentration, which induces the formation of gaseous HNO(3).

  3. Effect of reductant and PVP on morphology and magnetic property of ultrafine Ni powders prepared via hydrothermal route

    SciTech Connect

    Zhang, Jun Wang, Xiucai; Li, Lili; Li, Chengxuan; Peng, Shuge

    2013-10-15

    Graphical abstract: The ultrafine Ni powders with the shapes including sphere, pearl-string, leaf, fish-bone, hexagonal sheet and silknet were prepared through one-step hydrothermal reduction using different reductants. Their saturation magnetization, remanent magnetization and coercivity sequentially increase, and the coercivity of hexagonal sheet-like Ni powders increases by 25% compared with the Ni bulk counterpart. - Highlights: • The ultrafine Ni powders with various shapes of sphere, fish-bone, hexagonal sheet, etc. • Facile and one-step hydrothermal reduction using three reductants and PVP additive was developed. • Magnetic properties of the ultrafine Ni powders with different shapes were measured. • Compared with bulk Ni material, coercivity of hexagonal sheet Ni increases by 25%. • The formation mechanism of the shapes was suggested. - Abstract: The ultrafine nickel particles with different shapes including sphere, pearl-string, leaf, fish-bone, hexagonal sheet and silknet were prepared through one-step hydrothermal reduction using hydrazine hydrate, sodium hypophosphite and ethylene glycol as reductants, polyvinylpyrrolidone as structure-directing agent. It has been verified with the characterization of X-ray powder diffraction and transmission/scanning electronic microscopy that as-prepared products belong to face-centered cubic structure of nickel microcrystals with high purity and fine dispersity. The magnetic hysteresis loops measured at room temperature reveal that the values of saturation magnetization, remanent magnetization and coercivity rise sequentially from silknet, sphere to hexagonal sheet. In comparison with nickel bulk counterpart, the coercivity of the hexagonal sheet nickel powders increases by 25%.

  4. Removal of ultrafine and fine particulate matter from air by a granular bed filter.

    PubMed

    Ozis, Fethiye; Singh, Manisha; Devinny, Joseph; Sioutas, Constantinos

    2004-08-01

    The removal efficiency of granular filters packed with lava rock and sand was studied for collection of airborne particles 0.05-2.5 microm in diameter. The effects of filter depth, packing wetness, grain size, and flow rate on collection efficiency were investigated. Two packing grain sizes (0.3 and 0.15 cm) were tested for flow rates of 1.2, 2.4, and 3.6 L/min, corresponding to empty bed residence times (equal to the bulk volume of the packing divided by the airflow rate) in the granular media of 60, 30, and 20 sec, respectively. The results showed that at 1.2 L/min, dry packing with grains 0.15 cm in diameter removed more than 80% (by number) of the particles. Particle collection efficiency decreased with increasing flow rate. Diffusion was identified as the predominant collection mechanism for ultrafine particles, while the larger particles in the accumulation mode of 0.7-2.5 microm were removed primarily by gravitational settling. For all packing depths and airflow rates, particle removal efficiency was generally higher on dry packing than on wet packing for particles smaller than 0.25 microm. The results suggest that development of biological filters for fine particles is possible.

  5. Cumulative frequency fit for particle size distribution.

    PubMed

    Xu, Zhuyun; Gautam, Mridul; Mehta, Sandeep

    2002-08-01

    A cumulative frequency distribution fit method is presented for analyzing particle size distributions by minimizing the summation of the square of cumulative frequency errors. Compared to the frequency fit method, the cumulative frequency fit method yields a more accurate solution. Based upon this, a spreadsheet was developed for analyzing multi-modal particle size distribution. The motivation for the work presented in this article was the current interest in ultra-fine and nano-sized particle exhaust emissions from heavy-duty diesel engines. The new spreadsheet provides a quick and convenient way to conduct particle size distribution analysis.

  6. Characterization of pure Ni ultrafine/nanoparticles synthesized by electromagnetic levitational gas condensation method

    SciTech Connect

    Khodaei, Azin Hasannasab, Malihe; Amousoltani, Narges; Kermanpur, Ahmad

    2016-02-15

    Highlights: • Ni ultrafine/nanoparticles were produced using the single-step ELGC method. • Ar and He–20%Ar gas mixtures were used as the condensing gas under 1 atm. • Effects of gas type and flow rate on particle size distribution were investigated. • The nanoparticles showed both high saturation magnetization and low coercivity. - Abstract: In this work, Ni ultrafine/nanoparticles were directly produced using the one-step, relatively large-scale electromagnetic levitational gas condensation method. In this process, Ni vapors ascending from the levitated droplet were condensed by Ar and He–20%Ar gas mixtures under atmospheric pressure. Effects of type and flow rate of the condensing gas on the size, size distribution and crystallinity of Ni particles were investigated. The particles were characterized by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometer (VSM). The process parameters for the synthesis of the crystalline Ni ultrafine/nanoparticles were determined.

  7. Microscale simulations of shock interaction with large assembly of particles for developing point-particle models

    NASA Astrophysics Data System (ADS)

    Thakur, Siddharth; Neal, Chris; Mehta, Yash; Sridharan, Prasanth; Jackson, Thomas; Balachandar, S.

    2017-01-01

    Micrsoscale simulations are being conducted for developing point-particle and other related models that are needed for the mesoscale and macroscale simulations of explosive dispersal of particles. These particle models are required to compute (a) instantaneous aerodynamic force on the particle and (b) instantaneous net heat transfer between the particle and the surrounding. A strategy for a sequence of microscale simulations has been devised that allows systematic development of the hybrid surrogate models that are applicable at conditions representative of the explosive dispersal application. The ongoing microscale simulations seek to examine particle force dependence on: (a) Mach number, (b) Reynolds number, and (c) volume fraction (different particle arrangements such as cubic, face-centered cubic (FCC), body-centered cubic (BCC) and random). Future plans include investigation of sequences of fully-resolved microscale simulations consisting of an array of particles subjected to more realistic time-dependent flows that progressively better approximate the actual problem of explosive dispersal. Additionally, effects of particle shape, size, and number in simulation as well as the transient particle deformation dependence on various parameters including: (a) particle material, (b) medium material, (c) multiple particles, (d) incoming shock pressure and speed, (e) medium to particle impedance ratio, (f) particle shape and orientation to shock, etc. are being investigated.

  8. Cytocompatible and water stable ultrafine protein fibers for tissue engineering

    NASA Astrophysics Data System (ADS)

    Jiang, Qiuran

    This dissertation proposal focuses on the development of cytocompatible and water stable protein ultrafine fibers for tissue engineering. The protein-based ultrafine fibers have the potential to be used for biomedicine, due to their biocompatibility, biodegradability, similarity to natural extracellular matrix (ECM) in physical structure and chemical composition, and superior adsorption properties due to their high surface to volume ratio. However, the current technologies to produce the protein-based ultrafine fibers for biomedical applications still have several problems. For instance, the current electrospinning and phase separation technologies generate scaffolds composed of densely compacted ultrafine fibers, and cells can spread just on the surface of the fiber bulk, and hardly penetrate into the inner sections of scaffolds. Thus, these scaffolds can merely emulate the ECM as a two dimensional basement membrane, but are difficult to mimic the three dimensional ECM stroma. Moreover, the protein-based ultrafine fibers do not possess sufficient water stability and strength for biomedical applications, and need modifications such as crosslinking. However, current crosslinking methods are either high in toxicity or low in crosslinking efficiency. To solve the problems mentioned above, zein, collagen, and gelatin were selected as the raw materials to represent plant proteins, animal proteins, and denatured proteins in this dissertation. A benign solvent system was developed specifically for the fabrication of collagen ultrafine fibers. In addition, the gelatin scaffolds with a loose fibrous structure, high cell-accessibility and cell viability were produced by a novel ultralow concentration phase separation method aiming to simulate the structure of three dimensional (3D) ECM stroma. Non-toxic crosslinking methods using citric acid as the crosslinker were also developed for electrospun or phase separated scaffolds from these three proteins, and proved to be

  9. Development of a centrifugal float-sink procedure for gravimetric evaluation of ultrafine coals: Part 1, The effects of surface-property-related parameters on fine-coal separations

    SciTech Connect

    Cavallaro, J.A.; Killmeyer, R.P.

    1988-02-01

    This report traces the development of a centrifugal float-sink technique for determining the washability analyses of fine coal having top sizes finer than 14 mesh. All testing was performed on the Upper and Lower Kittanning bed coals only. The efforts of other researchers attempting to utilize the centrifuge for float-sink testing ultrafine coal are reviewed briefly. Exploratory test data from PETC are presented to show the effect of surfactant additions, reverse float-sink testing, and preheating of samples on the yield/ash relationships. The results of a 33-test partial factorial design used to evaluate five variables at five levels and their effects on the yield/ash relationship as depicted by an efficiency index are presented, along with follow-up tests showing the importance of lower solids concentration and higher reagent dosage. Coal moisture content and reagent dosage had the most significant effect on the yield/ash relationship. 12 refs., 9 figs., 16 tabs.

  10. Ultrafine hydrogen storage powders

    DOEpatents

    Anderson, Iver E.; Ellis, Timothy W.; Pecharsky, Vitalij K.; Ting, Jason; Terpstra, Robert; Bowman, Robert C.; Witham, Charles K.; Fultz, Brent T.; Bugga, Ratnakumar V.

    2000-06-13

    A method of making hydrogen storage powder resistant to fracture in service involves forming a melt having the appropriate composition for the hydrogen storage material, such, for example, LaNi.sub.5 and other AB.sub.5 type materials and AB.sub.5+x materials, where x is from about -2.5 to about +2.5, including x=0, and the melt is gas atomized under conditions of melt temperature and atomizing gas pressure to form generally spherical powder particles. The hydrogen storage powder exhibits improved chemcial homogeneity as a result of rapid solidfication from the melt and small particle size that is more resistant to microcracking during hydrogen absorption/desorption cycling. A hydrogen storage component, such as an electrode for a battery or electrochemical fuel cell, made from the gas atomized hydrogen storage material is resistant to hydrogen degradation upon hydrogen absorption/desorption that occurs for example, during charging/discharging of a battery. Such hydrogen storage components can be made by consolidating and optionally sintering the gas atomized hydrogen storage powder or alternately by shaping the gas atomized powder and a suitable binder to a desired configuration in a mold or die.

  11. Effect of multidirectional forging and equal channel angular pressing on ultrafine grain formation in a Cu- Cr-Zr alloy

    NASA Astrophysics Data System (ADS)

    Shakhova, I.; Belyakov, A.; Kaibyshev, R.

    2014-08-01

    The microstructure evolution was investigated in a Cu-0.3%Cr-0.5%Zr alloy subjected to large plastic deformation at temperature of 400 °C. Two methods of large plastic deformation, i.e., equal channel angular pressing (ECAP) and multidirectional forging (MDF) were used. The large plastic deformations resulted in the development of new ultrafine grains. The formation of new ultrafine grains occurred as a result of continuous reaction, i.e., progressive increase in the misorientations of deformation subboundaries. The faster kinetics of microstructure evolution was observed during MDF as compared to ECAP. The MDF to a total strain of 4 resulted in the formation of uniform ultrafine grained structure, while ECAP to the same strain led to the heterogeneous microstructure consisting of new ultrafine grains and coarse remnants of original grains. Corresponding area fractions of ultrafine grains comprised 0.23 and 0.59 in the samples subjected to ECAP and MDF, respectively.

  12. Ultrafine coal single stage dewatering and briquetting process

    SciTech Connect

    Wilson, J.W.; Honaker, R.Q.

    1995-12-31

    It is well known that a large portion of the pyrite particles in the coal seams of the Illinois Basin are finely disseminated within the coal matrix. In order to liberate these micron size pyrite particles, one must use a fine grinding operation. The ultrafine coal particles are difficult to dewater and create problems in coal transportation, as well as in storage and handling at utility plants. The objective of this research project is to combine the ultrafine coal dewatering and briquetting processes into a single stage operation. This will be accomplished by the use of bitumen based emulsions for dewatering and a compaction device for briquetting. During this reporting period, several types of coal samples with various particle size distributions have been tested for use in the dewatering and briquetting processes. Furthermore, various bitumen emulsions have been tested to determine the optimum dewatering reagent. These dewatering and pelletizing tests were carried out using a lab-scale ram extruder. Discharge from the dewatering and briquetting processes was tested to determine compliance with current federal and state requirements. The influence of bitumen emulsion on the sulfur content of coal pellets made were also examined. In addition, a ram extruder which can be operated continuously to simulate a rotary press operation, has been built and is currently being tested for use in the fine coal dewatering and pelletizing process.

  13. Preliminary attempt at sintering an ultrafine alumina powder using microwaves. Master's thesis

    SciTech Connect

    Alhambra, E.M.

    1994-09-01

    A commercially available microwave oven was used to sinter ultrafine alumina powders (0.02 - 0.05 micrometers particle size) with and without CaO sintering aid. The oven was modified by inserting a thermocouple probe through the bottom housing, and thoroughly insulating the interior with insulating material. The oven was placed in a glove box and filled with argon to prevent degradation of the thermocouple, and oxidation of the powdered graphite susceptor. Heating rates of 50-75 Deg C/sec with a maximum temperature of 1575 Deg C were obtained. Limited success in sintering of the the powder compacts was achieved in this preliminary effort. The microstructures of the sintered products were examined by scanning electron microscopy. It was concluded that further work is necessary to develop this technique into one which can be used for the routine sintering of fine powdered ceramic material. A review of the literature on microwave sintering of ceramic powders is also reported.

  14. Development of a Charged Particle Microbeam for Targeted and Single Particle Subcellular Irradiation

    SciTech Connect

    Yanch, Jacquelyn C.

    2004-03-12

    The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube.

  15. [Elemental size distribution of airborne fine and ultrafine particulate matters in the suburb of Shanghai, China].

    PubMed

    Lin, Jun; Liu, Wei; Li, Yan; Bao, Liang-Man; Li, Yu-Lan; Xu, Zhong-Yang; Wu, Wei-Wei; Chen, Dong-Liang; He, Wei

    2009-04-15

    The elemental size distributions of airborne fine/ultrafine particulate matters in the suburb of Shanghai were studied using synchrotron X-ray fluorescence. Median mass aerodynamic diameter (MMAD), elemental correlation coefficient as well as enrichment factor (EF) of each size fraction were calculated to characterize the sources of elements in fine/ultrafine particulate matters. Ca and Ti distributed mainly in coarse particles (> 2 microm) with size independent enrichment factors between 0.1 and 3.2, and the correlation coefficient between Ca and Ti was as high as 0.933, which implied strong contribution from nature sources, such as soil dusts and resuspended dusts. However, V, Cr, Mn, Ni, Zn, Cu, Pb, Cl, S mainly distributed in 0.1-1.0 microm particulate matters with MMAD between 0.56-0.94 microm. The EF of V, Cr, Ni, Cu, Zn, Pb increased with decreasing particle size. The highest EF were found for Pb in ultrafine particulate matters (< 0.1 microm) with EF of 2,023.7-2,244.2. The evidences suggested that these elements were significantly influenced by anthropogenic sources and enriched in fine/ultrafine particles smaller than 1 microm. Fe distributed uniformly in the particles larger than 0.2 microm with MMAD of 1.3 microm. The results indicated non-negligible influences of remote transmission of anthropogenic pollutions.

  16. Turbulent particle clustering in a fully developed square channel flow

    NASA Astrophysics Data System (ADS)

    Villafane, Laura; Banko, Andrew; Elkins, Chris; Eaton, John

    2015-11-01

    Particle-turbulence interactions are investigated in a fully developed turbulent channel air flow to determine the gas phase effect on the particle concentration and velocity fields. The experimental apparatus is a vertical channel with square cross section. The Reynolds number based on channel width is about 104. The 12 um nominal diameter nickel particles are smaller than the Kolmogorov length scale and the corresponding Stokes number is of the order of one. Low volume and mass loading ratios are considered. Under these conditions preferential concentration is expected to be strong while the effect of particles on the gas flow negligible. The square channel flow contains mean secondary flows not present in high aspect ratio channels studied previously. These will increase transport of particles away from the walls and raise turbulence levels in the central region. Current experiments are focused on the statistics of the particle phase including particle concentration inhomogeneities and particle velocities. The particle concentration field is analyzed from high resolution laser illuminated planar images. Particle velocity distributions are measured by PIV techniques and compared to the carrier-phase mean velocities from aerodynamic pressure measurements in the unladen case. The effect of increasing mass loading ratio on the particle velocities is analyzed. This Material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0002373-1.

  17. Ultrafine Betulin Formulation with Biocompatible Carriers Exhibiting Improved Dissolution Rate.

    PubMed

    Myza, Svetlana A; Shakhtshneidera, Tatyana P; Mikhailenkob, Mikhail A; Ogienkoc, Andrey G; Bogdanovaa, Ekaterina G; Ogienkoe, Anna A; Kuznetsovaf, Svetlana A; Boldyrevaa, Elena V; Boldyreva, Vladimir V

    2015-08-01

    The purpose of this research was to develop new methods of increasing dissolution rate and solubility of betulin extracted from birch bark. The ultrafine formulation of betulin with polyethylene glycol and β-glycine was obtained by freeze-drying. The rate of release of betulin from the formulation into water was significantly higher in comparison with the initial betulin sample and its composite with polyethylene glycol obtained by ball-milling.

  18. Preparation of Ultrafine W-Cu Composite Powder Using Ultrasonic-Assisted Electroless Plating

    NASA Astrophysics Data System (ADS)

    Huang, Limei; Luo, Laima; Ding, Xiaoyu; Zan, Xiang; Hong, Yu; Cheng, Jigui; Wu, Yucheng; Luo, Guangnan; Zhu, Liu

    2013-07-01

    W-Cu ultrafine/nanocomposite powders have high sintering activity, so ultrafine/nanotechnology of W-Cu composite powders is one of the main methods to obtain fully dense, high-performance W-Cu composite materials. Cu-coated ultrafine W composite powders were synthesized by ultrasonic-assisted electroless plating process with non-noble metal activation pretreatment at room temperature in this paper. The growth mechanism of Cu layers and surface morphologies and composition of initial ultrafine W powders, pretreated W powders and Cu-coated W powders were analyzed by field emission scanning electron microscopy (FE-SEM), and energy dispersion spectrometry (EDS). The results show that the uniformly Cu coated W composite powder is successfully synthesized without conventional sensitization and activation steps by ultrasonic-assisted electroless plating at room temperature. The Cu layers on the ultrafine W powders had cell structure with dense, uniform distribution. The growth mechanism of Cu layers appears as follows: the surfaces of pretreated W powders appear linear-like and lamellar-like surface defects which act as activated sites. The reactants in the plating solution were adsorbed on catalytic activity surfaces of powders and happened oxidation-reduction reaction. The growth and aggregation mechanisms of Cu particles after nucleation are stripy Cu-cells grew up, bend, bifurcated, and aggregated, then wounding into a cellular structure, like "wrapping wool clusters" in the life. Finally, Cu cells grow up and merge into a layer.

  19. Stress and Microstructure Development in Particle-Based Coatings

    NASA Astrophysics Data System (ADS)

    Price, Kyle Kirk-Arthur

    Particle-based coatings have a wide range of uses and applications in everyday life. Stress development during the drying process has the potential to impact the performance of the coating. Stress development can be monitored in-situ using a cantilever deflection technique with a laser-photodiode combination. Stress development in the film is directly related to the development of the coating microstructure during drying. Cryogenic scanning electron microscopy (cryoSEM) is a powerful characterization method capable of visualizing the microstructure of the coating during the intermediate stages of drying. Using this method, the coating is frozen to arrest microstructure development and solidify the sample so that it can survive the high-vacuum environment of the SEM. This thesis explores the connections between stress and microstructure development in particle-based coatings during drying. Characterization is often complicated by lateral drying, a common phenomenon in particle-based coatings. To avoid these complications, walled substrates were developed which are used to suppress lateral drying and promote drying uniformity. CryoSEM revealed that latex coatings dried on substrates (with photoresist walls) exhibit a greater degree of drying uniformity. Silicon cantilevers with poly(dimethyl siloxane) (PDMS) walls along the perimeter were used to suppress the effects of lateral drying during stress measurement. The walled cantilevers were used to characterize stress development in ceramic particle coatings and latex films. For the ceramic particle coatings, stress measurements were combined with cryoSEM revealing the origins of stress development in hard particle coatings. Stress development was correlated with the extent of drying and the degree of saturation in the coating. Stress development in latex particle coatings was influenced by the composition and morphology of the latex particles. Additionally, the influence of coalescing aids on stress development was

  20. The preparation and characterization of highly aligned poly(epsilon-caprolactone)/poly ethylene oxide/chitosan ultrafine fiber for the application to tissue scaffold.

    PubMed

    Nien, Yu-Hsun; Wang, Jia-Yi; Tsai, Yan-Sheng

    2013-07-01

    The purpose of this study was to fabricate poly(epsilon-caprolactone) (PCL)/poly ethylene oxid (PEO)/chitosan (CS) ultrafine fiber in both aligned and random structures using electrospinning technique and their process parameters were optimized. The aligned and random PCL/PEO/chitosan ultrafine fibers were also used as scaffold for tissue engineering and their cell affinity was investigated. In the first part, we inspected the effect of environment conditions, solution properties, process parameters on PCL/PEO/chitosan ultrafine fiber. In the second part, the apparatus of electrospinning to manufacture highly aligned PCL/PEO/chitosan ultrafine fiber was developed. The effects of process parameters such as flow rate, design of collector and rotation speed of collecting drum on the morphology of ultrafine fiber were discussed. In addition, the cross link of PCL/PEO/chitosan ultrafine fiber by cross-linking agent was examined, too. The physical properties, chemical properties, and cell affinities of the aligned PCL/PEO/chitosan ultrafine fiber with or without cross link were measured. The chemical analysis and tensile strength of the ultrafine fiber were characterized using Fourier Transfer Infared Spectrophotometer and Universal Tensile Machine, respectively. The results show that the aligned PCL/PEO/chitosan ultrafine fibrous mat had the capacity to induce cellular alignment and enhance cellular elongation.

  1. Ultrafine-grained titanium for medical implants

    DOEpatents

    Zhu, Yuntian T.; Lowe, Terry C.; Valiev, Ruslan Z.; Stolyarov, Vladimir V.; Latysh, Vladimir V.; Raab, Georgy J.

    2002-01-01

    We disclose ultrafine-grained titanium. A coarse-grained titanium billet is subjected to multiple extrusions through a preheated equal channel angular extrusion (ECAE) die, with billet rotation between subsequent extrusions. The resulting billet is cold processed by cold rolling and/or cold extrusion, with optional annealing. The resulting ultrafine-grained titanium has greatly improved mechanical properties and is used to make medical implants.

  2. Graphite to ultrafine nanocrystalline diamond phase transition model and growth restriction mechanism induced by nanosecond laser processing

    NASA Astrophysics Data System (ADS)

    Ren, X. D.; Liu, R.; Zheng, L. M.; Ren, Y. P.; Hu, Z. Z.; He, H.

    2015-10-01

    To have a clear insight into nanocrystal growth from graphite to diamond upon high energy pulsed laser irradiation of graphite suspension, synthesis of ultrafine nanocrystalline diamonds with laser energy set up from 0.3 J to 12 J, repetition rate of 10 Hz has been studied. The method allows synthesizing ultrafine nanocrystalline particles continuously at the ambient temperature and normal pressure. The particle size is shown independent of laser energy, which is ultrafine and ranges in 2-6 nm. The theoretical grown size of nano-diamonds is found in well agreement with the experiment results. Four kinds of production were found: nano-diamond, spherical carbon nano-particles, flocculent amorphous carbon, and graphene nano-ribbon rolls. A solid-vapor-plasma-liquid coexistence model describing phase transition from graphite to diamond induced by nanosecond laser processing was proposed. Graphene nano-ribbon rolls might be the intermediate phase in the conversion from graphite to diamond.

  3. Sintering behavior of ultrafine silicon carbide powders obtained by vapor phase reaction

    NASA Technical Reports Server (NTRS)

    Okabe, Y.; Miyachi, K.; Hojo, J.; Kato, A.

    1984-01-01

    The sintering behavior of ultrafine SiC powder with average particle size of about 0.01-0.06 microns produced by a vapor phase reaction of the Me4Si-H2 system was studied at the temperature range of 1400-2050 deg. It was found that the homogeneous dispersion of C on SiC particles is important to remove the surface oxide layer effectively. B and C and inhibitive effect on SiC grain growth.

  4. Dissolution of populations of ultrafine grains with applications to feldspars

    SciTech Connect

    Talman, S.J.; Nesbitt, H.W. )

    1988-06-01

    Mineral dissolution studies are difficult to interpret when the solid reactant displays a wide range in grain sizes, since the rate of dissolution of the finest grains may not be simply related to their surface area. The transient apparent rate of dissolution of a population of fine-grained reactants is modeled to predict changes to the solution composition, as well as changes in the size distribution of ultra-fine particles as functions of time. The model is applies to the experimental data on Amelia albite of Hodlren and Berner (1979) from which both solution composition and grain size distribution have been obtained. The observed size distribution cannot be duplicated if the dissolution rate is proportional to surface area (i.e. dV/dt=Kr{sup 2}); other contributions to the rate, such as dependence on grain size and the specific contributions from edges and corners, must be invoked. The observed grain size distribution and pseudo-parabolic rate can be reproduced when the rate of dissolution of the fine grains is proportional to its radius (i.e. dV/dt=Kr). The rate constant, K, is consistent with a rate limited by dissolution at the edges of the grains. The possibility of predicting both the contributions of ultrafine particles to the observed dissolution rate and the time evolution of the grain size distribution makes the model a useful tool for interpreting mineral dissolution data.

  5. Particle toxicology: from coal mining to nanotechnology.

    PubMed

    Borm, Paul J A

    2002-03-01

    Particle research has been historically closely connected to industrial activities or materials, such as coal, asbestos, man-made mineral fibers, and more recently ambient particulate matter (PM). It is the purpose of this review to combine insights and developments in particle toxicology with the historical context of exposure and organizations sponsoring such research in Europe. In supporting research on particle-induced respiratory effects and mechanisms, research programs of the European Community on Steel and Coal (ECSC) have played a tremendous role. Current particle research in Europe is dominated by PM, and funded by the World Health Organization (WHO), European Union Framework programs, and the Health Effects Institute (HEI). Differences between historical and current research in particle toxicology include the exposure concentrations, particle size, target populations, endpoints, and length of exposure. Inhaled particle effects are no longer confined to the lung, since particles are suggested to translocate to the blood while lung inflammation invokes systemic responses. Finally, the particle size and concentrations have both been reduced about 100-fold from 2-5 mg/m3 to 20-50 mg/m3 and from 1-2 microm to 20-100 nm (ultrafine) as domestic fuel burning has decreased and vehicle sources have increased and attention has moved from coal mining industry to general environment. There is, however, a further occupational link to nanotechnology, which continuously produces new materials in the ultrafine range. Although inhalation exposure is considered to be minimal in this technology, some particles are produced to be used for carrier purpose in medical applications. Based on our current knowledge of particle toxicology, it is highly desirable that toxicology and technology are linked in this extremely rapid developing area, to learn more about potential risks and also to develop knowledge on the role of surface and size in particle toxicity.

  6. Stabilization of ultrafine metal nanocatalysts on thin carbon sheets

    NASA Astrophysics Data System (ADS)

    Liu, Xiaofang; Cui, Xinrui; Liu, Yiding; Yin, Yadong

    2015-10-01

    A novel strategy was proposed to anchor ultrafine metal nanoparticles (NPs) on thin carbon sheets for highly stable and efficient heterogeneous catalysts. In this facile approach, a dense monolayer of ultrafine AuNPs was sandwiched between a silica core and a resin shell, followed by carbonization of the shell at a high temperature and then selective removal of the silica core. The shrinkage of the shells during carbonization facilitates partial embedment of the AuNPs on the carbon shell surface and provides superior stability against particle sintering during high temperature/mechanical post-treatments and catalytic reactions. It was also found that diffusion of reactants to the surface of AuNPs could be maximized by reducing the thickness of the hollow shells or simply by cracking the shells into thin carbon sheets, both significantly benefiting the catalytic efficiency. The advantages of this ultra-stable architecture together with the densely dispersed catalytic sites were demonstrated by their high stability and superior catalytic activity in reducing hydrophilic 4-nitrophenol and hydrophobic nitrobenzene.A novel strategy was proposed to anchor ultrafine metal nanoparticles (NPs) on thin carbon sheets for highly stable and efficient heterogeneous catalysts. In this facile approach, a dense monolayer of ultrafine AuNPs was sandwiched between a silica core and a resin shell, followed by carbonization of the shell at a high temperature and then selective removal of the silica core. The shrinkage of the shells during carbonization facilitates partial embedment of the AuNPs on the carbon shell surface and provides superior stability against particle sintering during high temperature/mechanical post-treatments and catalytic reactions. It was also found that diffusion of reactants to the surface of AuNPs could be maximized by reducing the thickness of the hollow shells or simply by cracking the shells into thin carbon sheets, both significantly benefiting the

  7. 24-gauge ultrafine cryoprobe with diameter of 550 μm and its cooling performance.

    PubMed

    Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

    2014-12-01

    This paper describes the development of a novel cryoprobe with the same size as a 24-gauge injection needle and the evaluation of its cooling performance. This ultrafine cryoprobe was designed to reduce the invasiveness and extend application areas of cryosurgery. The ultrafine cryoprobe has a double-tube structure and consists of two stainless steel microtubes. The outer diameter of the cryoprobe is 550 μm, and the inner tube has a 70-μm inner diameter to depressurize the high-pressure refrigerant. By solving the bioheat transfer equation and considering freezing phenomena, the relationship between the size of the frozen region and the heat transfer coefficient of the refrigerant flow in an ultrafine cryoprobe was derived analytically. The results showed that the size of the frozen region is strongly affected by the heat transfer coefficient. A high heat transfer coefficient such as that of phase change heat transfer is required to generate a frozen region of sufficient size. In the experiment, trifluoromethane (HFC-23) was used as the refrigerant, and the cooling effects of the gas and liquid phase states at the inlet were evaluated. When the ultrafine cryoprobe was cooled using a liquid refrigerant, the surface temperature was approximately -50°C, and the temperature distribution on the surface was uniform for a thermally insulated condition. However, for the case with vaporized refrigerant, the temperature distribution was not uniform. Therefore, it was concluded that the cooling mechanism using liquid refrigerant was suitable for ultrafine cryoprobes. Furthermore, to simulate cryosurgery, a cooling experiment using hydrogel was conducted. The results showed that the surface temperature of the ultrafine cryoprobe reached -35°C and formed a frozen region with a radius of 4 mm in 4 min. These results indicate that the ultrafine cryoprobe can be applied in actual cryosurgeries for small affected areas.

  8. Development of Interconnect Technologies for Particle Detectors

    SciTech Connect

    Tripathi, Mani

    2015-01-29

    This final report covers the three years of this grant, for the funding period 9/1/2010 - 8/31/2013. The project consisted of generic detector R&D work at UC Davis, with an emphasis on developing interconnect technologies for applications in HEP. Much of the work is done at our Facility for Interconnect Technologies (FIT) at UC Davis. FIT was established using ARRA funds, with further studies supported by this grant. Besides generic R&D work at UC Davis, FIT is engaged in providing bump bonding help to several DOE supported detector R&D efforts. Some of the developmental work was also supported by funding from other sources: continuing CMS project funds and the Linear Collider R&D funds. The latter program is now terminated. The three year program saw a good deal of progress on several fronts, which are reported here.

  9. Dispersion of fine phosphor particles by newly developed beads mill

    NASA Astrophysics Data System (ADS)

    Joni, I. Made; Panatarani, C.; Maulana, Dwindra W.

    2016-02-01

    Fine phosphor Y2O3:Eu3+ particles has advanced properties compare to conventional particles applied for compact fluorescent lamp (CFL) as three band phosphor. However, suspension of fine particles easily agglomerated during preparation of spray coating of the CFL tube. Therefore, it is introduced newly developed beads mill system to disperse fine phosphor. The beads mill consist of glass beads, dispersing chamber (impellers), separator chamber, slurry pump and motors. The first important performance of beads mill is the performance of the designed on separating the beads with the suspended fine particles. We report the development of beads mill and its separation performance vary in flow rate and separator rotation speeds. The 27 kg of glass beads with 30 µm in size was poured into dispersing chamber and then water was pumped continuously through the slurry pump. The samples for the separation test was obtained every 1 hours vary in rotation speed and slurry flow rate. The results shows that the separation performance was 99.99 % obtained for the rotation speed of >1000 rpm and flow rate of 8 L/minute. The performances of the system was verified by dispersing fine phosphor Y2O3:Eu3+ particles with concentration 1 wt.%. From the observed size distribution of particles after beads mill, it is concluded that the current design of bead mill effectively dispersed fine phosphor Y2O3:Eu3+.

  10. Increased inflammation and intracellular calcium caused by ultrafine carbon black is independent of transition metals or other soluble components

    PubMed Central

    Brown, D; Stone, V; Findlay, P; MacNee, W; Donaldson, K

    2000-01-01

    OBJECTIVES—Particulate air pollution has been shown to cause adverse health effects, and the ultrafine particle component has been implicated. The aim of the present study was to investigate whether an ultrafine particle exerted its effects through transition metals or other soluble factors released from the surface of the particles.
METHODS—Both in vitro and in vivo models were used to test the imflammogenicity of carbon black (CB) and ultrafine carbon black (UfCB) and the role of transition metals was investigated by treating the particles with desferrioxamine mesylate (desferal), a transition metal chelator. Rats were instilled with particles and the cell population assessed by bronchoalveolar lavage (BAL). Calcium homeostasis in macrophages was assessed with a fluorimetric technique.
RESULTS—UfCB was inflammogenic compared with CB when instilled into Wistar rat lungs, an effect which could not be ameliorated by desferal treatment of the particles. Particle leachates produced no significant inflammation in vivo. In vitro experiments showed that the cytosolic calcium ion concentration in Mono Mac 6 cells was increased significantly after UfCB treatment and treatment of particles with desferal did not alter these effects. Particle leachates had no effect on cytosolic calcium ion concentration. Iron was not detected in leachates of the particles with the desferal assay, however, ng/mg of particles were detectable in citrate leachates with inductively coupled plasma-mass spectrometry (ICP-MS).
CONCLUSIONS—The increased inflammogenicity of UfCB compared with CB cannot be explained by soluble transition metals released from or by accumulation of iron at the particle surface. Differences may be accounted for by increased surface area or particle number.


Keywords: ultrafine; calcium; transition metals PMID:10984341

  11. Intercomparison of four methods to determine size distributions of low-concentration (approximately 100 cm[sup [minus]3]), ultrafine aerosols (3 < D[sub p] < 10 nm) with illustrative data from the Arctic

    SciTech Connect

    Wiedensohler, A. ); Aalto, P. ); Covert, D. ); Heintzenberg, J. ); McMurry, P.H. )

    1994-08-01

    Four different methods for measuring ultrafine particle size distributions in the 3-10-nm particle diameter range are compared and discussed. These methods all use an ultrafine condensation particle counter (TSI Inc. Model 3025 or its prototype) as the detector, but use different approaches to determine the size of the particles counted. Size classification was achieved using a Hauke Model VIE-06 differential mobility analyzer, a specially configured TSI Model 3040S diffusion battery, an ultrafine condensation particle counter with a variable condenser temperature, and an ultrafine condensation particle counter with a pulse height analyzer for signals produced by the optical detector. The response of these systems to ultrafine particles of known size and composition was studied during a workshop held in Lund, Sweden, during July 1991. After this workshop, measurements of ultrafine particles were made on the Swedish icebreaker Oden during the International Arctic Ocean Expedition 1991 (August 1, 1991 through October 7, 1991). In this article, the results of these laboratory and field measurements are discussed. The strengths and limitations of these measurement methods are emphasized. 30 refs., 9 figs., 3 tabs.

  12. Synthesis of ultrafine powders by microwave heating

    DOEpatents

    Meek, Thomas T.; Sheinberg, Haskell; Blake, Rodger D.

    1988-01-01

    A method of synthesizing ultrafine powders using microwaves is described. A water soluble material is dissolved in water and the resulting aqueous solution is exposed to microwaves until the water has been removed. The resulting material is an ultrafine powder. This method can be used to make Al.sub.2 O.sub.3, NiO+Al.sub.2 O.sub.3 and NiO as well as a number of other materials including GaBa.sub.2 Cu.sub.3 O.sub.x.

  13. Synthesis of ultrafine powders by microwave heating

    DOEpatents

    Meek, T.T.; Sheinberg, H.; Blake, R.D.

    1987-04-24

    A method of synthesizing ultrafine powders using microwaves is described. A water soluble material is dissolved in water and the resulting aqueous solution is exposed to microwaves until the water has dissolved. The resulting material is an ultrafine powder. This method can be used to make Al/sub 2/O/sub 3/, NiO /plus/ Al/sub 2/O/sub 3/ and NiO as well as a number of other materials including GaBa/sub 2/Cu/sub 3/O/sub x/. 1 tab.

  14. Inhaled Pollutants: The Molecular Scene behind Respiratory and Systemic Diseases Associated with Ultrafine Particulate Matter

    PubMed Central

    Traboulsi, Hussein; Guerrina, Necola; Iu, Matthew; Maysinger, Dusica; Ariya, Parisa; Baglole, Carolyn J.

    2017-01-01

    Air pollution of anthropogenic origin is largely from the combustion of biomass (e.g., wood), fossil fuels (e.g., cars and trucks), incinerators, landfills, agricultural activities and tobacco smoke. Air pollution is a complex mixture that varies in space and time, and contains hundreds of compounds including volatile organic compounds (e.g., benzene), metals, sulphur and nitrogen oxides, ozone and particulate matter (PM). PM0.1 (ultrafine particles (UFP)), those particles with a diameter less than 100 nm (includes nanoparticles (NP)) are considered especially dangerous to human health and may contribute significantly to the development of numerous respiratory and cardiovascular diseases such as chronic obstructive pulmonary disease (COPD) and atherosclerosis. Some of the pathogenic mechanisms through which PM0.1 may contribute to chronic disease is their ability to induce inflammation, oxidative stress and cell death by molecular mechanisms that include transcription factors such as nuclear factor κB (NF-κB) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2). Epigenetic mechanisms including non-coding RNA (ncRNA) may also contribute towards the development of chronic disease associated with exposure to PM0.1. This paper highlights emerging molecular concepts associated with inhalational exposure to PM0.1 and their ability to contribute to chronic respiratory and systemic disease. PMID:28125025

  15. Suppression of methane/air explosion by ultrafine water mist containing sodium chloride additive.

    PubMed

    Cao, Xingyan; Ren, Jingjie; Zhou, Yihui; Wang, Qiuju; Gao, Xuliang; Bi, Mingshu

    2015-03-21

    The suppression effect of ultrafine mists on methane/air explosions with methane concentrations of 6.5%, 8%, 9.5%, 11%, and 13.5% were experimentally studied in a closed visual vessel. Ultrafine water/NaCl solution mist as well as pure water mist was adopted and the droplet sizes of mists were measured by phase doppler particle analyzer (PDPA). A high speed camera was used to record the flame evolution processes. In contrast to pure water mist, the flame propagation speed, the maximum explosion overpressure (ΔP(max)), and the maximum pressure rising rate ((dP/dt)max) decreased significantly, with the "tulip" flame disappearing and the flame getting brighter. The results show that the suppressing effect on methane explosion by ultrafine water/NaCl solution mist is influenced by the mist amount and methane concentration. With the increase of the mist amount, the pressure, and the flame speed both descended significantly. And when the mist amount reached 74.08 g/m(3) and 37.04 g/m(3), the flames of 6.5% and 13.5% methane explosions can be absolutely suppressed, respectively. All of results indicate that addition of NaCl can improve the suppression effect of ultrafine pure water mist on the methane explosions, and the suppression effect is considered due to the combination effect of physical and chemical inhibitions.

  16. Micro-to-nano-scale deformation mechanisms of a bimodal ultrafine eutectic composite.

    Pub