Numerical modeling of fine particle fractal aggregates in turbulent flow

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Cao Feifeng

2015-01-01

Full Text Available A method for prediction of fine particle transport in a turbulent flow is proposed, the interaction between particles and fluid is studied numerically, and fractal agglomerate of fine particles is analyzed using Taylor-expansion moment method. The paper provides a better understanding of fine particle dynamics in the evolved flows.

Indoor PM1, PM2.5, PM10 and outdoor PM2.5 concentrations in primary schools in Sari, Iran.

Science.gov (United States)

Mohammadyan, Mahmoud; Shabankhani, Bijan

2013-09-01

This study was carried out to determine the distribution of particles in classrooms in primary schools located in the centre of the city of Sari, Iran and identify the relationship between indoor classroom particle levels and outdoor PM2.5 concentrations. Outdoor PM2.5 and indoor PM1, PM2.5, and PM10 were monitored using a real-time Micro Dust Pro monitor and a GRIMM monitor, respectively. Both monitors were calibrated by gravimetric method using filters. The Kolmogorov-Smirnov test showed that all indoor and outdoor data fitted normal distribution. Mean indoor PM1, PM2.5, PM10 and outdoor PM2.5 concentrations for all of the classrooms were 17.6 μg m(-3), 46.6 μg m(-3), 400.9 μg m(-3), and 36.9 μg m(-3), respectively. The highest levels of indoor and outdoor PM2.5 concentrations were measured at the Shahed Boys School (69.1 μg m(-3) and 115.8 μg m(-3), respectively). The Kazemi school had the lowest levels of indoor and outdoor PM2.5 (29.1 μg m(-3) and 15.5 μg m(-3), respectively). In schools located near both main and small roads, the association between indoor fine particle (PM2.5 and PM1) and outdoor PM2.5 levels was stronger than that between indoor PM10 and outdoor PM2.5 levels. Mean indoor PM2.5 and PM10 and outdoor PM2.5 were higher than the standards for PM2.5 and PM10, and there was a good correlation between indoor and outdoor fine particle concentrations.

Effects of types of ventilation system on indoor particle concentrations in residential buildings.

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Park, J S; Jee, N-Y; Jeong, J-W

2014-12-01

The objective of this study was to quantify the influence of ventilation systems on indoor particle concentrations in residential buildings. Fifteen occupied, single-family apartments were selected from three sites. The three sites have three different ventilation systems: unbalanced mechanical ventilation, balanced mechanical ventilation, and natural ventilation. Field measurements were conducted between April and June 2012, when outdoor air temperatures were comfortable. Number concentrations of particles, PM2.5 and CO2 , were continuously measured both outdoors and indoors. In the apartments with natural ventilation, I/O ratios of particle number concentrations ranged from 0.56 to 0.72 for submicron particles, and from 0.25 to 0.60 for particles larger than 1.0 μm. The daily average indoor particle concentration decreased to 50% below the outdoor level for submicron particles and 25% below the outdoor level for fine particles, when the apartments were mechanically ventilated. The two mechanical ventilation systems reduced the I/O ratios by 26% for submicron particles and 65% for fine particles compared with the natural ventilation. These results showed that mechanical ventilation can reduce exposure to outdoor particles in residential buildings. Results of this study confirm that mechanical ventilation with filtration can significantly reduce indoor particle levels compared with natural ventilation. The I/O ratios of particles substantially varied at the naturally ventilated apartments because of the influence of variable window opening conditions and unsteadiness of wind flow on the penetration of outdoor air particles. For better prediction of the exposure to outdoor particles in naturally ventilated residential buildings, it is important to understand the penetration of outdoor particles with variable window opening conditions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Chemical characterisation of fine particles from biomass burning

Energy Technology Data Exchange (ETDEWEB)

Saarnio, K.

2013-10-15

Biomass burning has lately started to attract attention because there is a need to decrease the carbon dioxide (CO{sub 2}) emissions from the combustion of fossil fuels. Biomass is considered as CO{sub 2} neutral fuel. However, the burning of biomass is one of the major sources of fine particles both at the local and global scale. In addition to the use of biomass as a fuel for heat energy production, biomass burning emissions can be caused, e.g. by slash-and-burn agriculture and wild open-land fires. Indeed, the emissions from biomass burning are crucially important for the assessment of the potential impacts on global climate and local air quality and hence on human health. The chemical composition of fine particles has a notable influence on these impacts. The overall object of this thesis was to gain knowledge on the chemistry of fine particles that originate from biomass burning as well as on the contribution of biomass burning emissions to the ambient fine particle concentrations. For this purpose novel analytical methods were developed and tested in this thesis. Moreover, the thesis is based on ambient aerosol measurements that were carried out in six European countries at 12 measurement sites during 2002-2011. Additionally, wood combustion experiments were conducted in a laboratory. The measurements included a wide range of techniques: filter and impactor samplings, offline chemical analyses (chromatographic and mass spectrometric techniques, thermal-optical method), and online measurements of particles' physical properties and chemical composition (incl. particle number and mass concentrations and size distributions, concentrations of carbonaceous components, water-soluble ions, and tracer compounds). This thesis presents main results of different studies aimed towards chemical characterisation of fine particle emissions from biomass burning. It was found that wood combustion had a significant influence on atmospheric fine particle concentrations in

Coupling fine particle and bedload transport in gravel-bedded streams

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Park, Jungsu; Hunt, James R.

2017-09-01

Fine particles in the silt- and clay-size range are important determinants of surface water quality. Since fine particle loading rates are not unique functions of stream discharge this limits the utility of the available models for water quality assessment. Data from 38 minimally developed watersheds within the United States Geological Survey stream gauging network in California, USA reveal three lines of evidence that fine particle release is coupled with bedload transport. First, there is a transition in fine particle loading rate as a function of discharge for gravel-bedded sediments that does not appear when the sediment bed is composed of sand, cobbles, boulders, or bedrock. Second, the discharge at the transition in the loading rate is correlated with the initiation of gravel mobilization. Third, high frequency particle concentration and discharge data are dominated by clockwise hysteresis where rising limb discharges generally have higher concentrations than falling limb discharges. These three observations across multiple watersheds lead to a conceptual model that fine particles accumulate within the sediment bed at discharges less than the transition and then the gravel bed fluidizes with fine particle release at discharges above the transition discharge. While these observations were individually recognized in the literature, this analysis provides a consistent conceptual model based on the coupling of fine particle dynamics with filtration at low discharges and gravel bed fluidization at higher discharges.

Ultrafine and Fine Particulate Matter Inside and Outside of Mechanically Ventilated Buildings.

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Miller, Shelly L; Facciola, Nick A; Toohey, Darin; Zhai, John

2017-01-28

The objectives of this study were to measure levels of particulate matter (PM) in mechanically ventilated buildings and to improve understanding of filtration requirements to reduce exposure. With the use of an Ultra High Sensitivity Aerosol Spectrometer and an Aerodyne Mass Spectrometer, ultrafine (0.055-0.1 μm) and fine (0.1-0.7 μm) indoor and outdoor PM was measured as a function of time in an office, a university building, and two elementary schools. Indoor particle levels were highly correlated with outdoor levels. Indoor and outdoor number concentrations in Denver were higher than those in Boulder, with the highest number concentrations occurring during summer and fall. The ratio of indoor-to-outdoor (I/O) PM was weakly but positively correlated with the amount of ventilation provided to the indoor environment, did not vary much with particle size (ranged between 0.48 and 0.63 for the entire size range), and was similar for each period of the week (weekend vs. weekday, night vs. day). Regression analyses showed that ultrafine indoor PM baseline concentrations were higher at night from nighttime infiltration. A lag time was observed between outdoor and indoor measurements. Weekday days had the shortest lag time of 11 min, and weekend nighttime lags when the HVAC was not in use were 50 to 148 min. Indoor-outdoor PM concentration plots showed ultrafine PM was more correlated compared to fine, and especially when the HVAC system was on. Finally, AMS data showed that most of the PM was organic, with occasional nitrate events occurring outdoors. During nitrate events, there were less indoor particles detected, indicating a loss of particulate phase nitrate. The results from this study show that improved filtration is warranted in mechanically ventilated buildings, particularly for ultrafine particles, and that nighttime infiltration is significant depending on the building design.

Autonomous patterning of cells on microstructured fine particles

International Nuclear Information System (INIS)

Takeda, Iwori; Kawanabe, Masato; Kaneko, Arata

2015-01-01

Regularly patterned cells can clarify cellular function and are required in some biochip applications. This study examines cell patterning along microstructures and the effect of microstructural geometry on selective cellular adhesion. Particles can be autonomously assembled on a soda-lime glass substrate that is chemically patterned by immersion in a suspension of fine particles. By adopting various sizes of fine particles, we can control the geometry of the microstructure. Cells adhere more readily to microstructured fine particles than to flat glass substrate. Silica particles hexagonally packed in 5–40 μm line and space microstructures provide an effective cell scaffold on the glass substrate. Cultured cells tend to attach and proliferate along the microstructured region while avoiding the flat region. The difference in cell adhesion is attributed to their geometries, as both of the silica particles and soda-lime glass are hydrophilic related with cell adhesiveness. After cell seeding, cells adhered to the flat region migrated toward the microstructured region. For most of the cells to assemble on the scaffold, the scaffolding microstructures must be spaced by at most 65 μm. - Highlights: • PS and SiO 2 particles provide effective scaffolds for cells. • Cells that adhere to microstructured particles successfully proliferate and differentiate. • Selective adhesion and growth along the scaffold can be achieved by patterning the fine particle microstructure. • Cells adhered to flat regions migrate toward microstructured regions. • Selective adhesion by cells depends on the microstructural geometry; specifically, on the inter-line spacing

Inorganic and carbonaceous components in indoor/outdoor particulate matter in two residential houses in Oslo, Norway.

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Lazaridis, Mihalis; Aleksandropoulou, Victoria; Hanssen, Jan Erik; Dye, Christian; Eleftheriadis, Kostantinos; Katsivela, Eleftheria

2008-03-01

A detailed analysis of indoor/outdoor physicochemical aerosol properties has been performed. Aerosol measurements were taken at two dwellings, one in the city center and the other in the suburbs of the Oslo metropolitan area, during summer/fall and winter/spring periods of 2002-2003. In this paper, emphasis is placed on the chemical characteristics (water-soluble ions and carbonaceous components) of fine (PM2.5) and coarse (PM2.5-10) particles and their indoor/outdoor relationship. Results demonstrate that the carbonaceous species were dominant in all fractions of the PM10 particles (cut off size: 0.09-11.31 microm) during all measurement periods, except winter 2003, when increased concentrations of water-soluble inorganic ions were predominant because of sea salt transport. The concentration of organic carbon was higher in the fine and coarse PM10 fractions indoors, whereas elemental carbon was higher indoors only in the coarse fraction. In regards to the carbonaceous species, local traffic and secondary organic aerosol formation were, probably, the main sources outdoors, whereas indoors combustion activities such as preparation of food, burning of candles, and cigarette smoking were the main sources. In contrast, the concentrations of water-soluble inorganic ions were higher outdoors than indoors. The variability of water-soluble inorganic ion concentrations outdoors was related to changes in emissions from local anthropogenic sources, long-range transport of particles, sea salt emissions, and resuspension of roadside and soil dusts. In the indoor environment the infiltration of the outdoor air indoors was the major source of inorganic ions.

Source contributions to atmospheric fine carbon particle concentrations

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Andrew Gray, H.; Cass, Glen R.

A Lagrangian particle-in-cell air quality model has been developed that facilitates the study of source contributions to atmospheric fine elemental carbon and fine primary total carbon particle concentrations. Model performance was tested using spatially and temporally resolved emissions and air quality data gathered for this purpose in the Los Angeles area for the year 1982. It was shown that black elemental carbon (EC) particle concentrations in that city were dominated by emissions from diesel engines including both on-highway and off-highway applications. Fine primary total carbon particle concentrations (TC=EC+organic carbon) resulted from the accumulation of small increments from a great variety of emission source types including both gasoline and diesel powered highway vehicles, stationary source fuel oil and gas combustion, industrial processes, paved road dust, fireplaces, cigarettes and food cooking (e.g. charbroilers). Strategies for black elemental carbon particle concentration control will of necessity need to focus on diesel engines, while controls directed at total carbon particle concentrations will have to be diversified over a great many source types.

Health effects from indoor and outdoor exposure to fine particulate matter in life cycle impact assessment

DEFF Research Database (Denmark)

Fantke, Peter; McKone, T.E.; Jolliet, Olivier

2016-01-01

Exposure to fine particulate matter (PM2.5) pollution is a major contributor to human disease burden as continuously shown in the Global Burden of Disease study series. Exposures to PM2.5 concentration outdoors and indoors contribute almost equally to this burden. Despite the importance, health...... impacts from exposure to PM2.5 are often excluded from life cycle impact assessment (LCIA) characterization profiles. This is in large part because of the lack of well-vetted harmonized guidance about how to consistently assess the exposures and impacts of indoor and outdoor emissions of PM2.5 and its...... precursors. We present a framework for calculating characterization factors for indoor and outdoor emissions of primary PM2.5 and secondary PM2.5 precursors, and a roadmap for further refining this modelling framework for operational use in LCIA. The framework was developed over the last three years...

[Health evaluation of fine particulate matter in indoor air].

Science.gov (United States)

2008-11-01

When evaluating the health effects of indoor air fine particulate matter, the indoor dynamics as well as the physical, chemical and biological properties of fine particles have to be considered. The indoor air fraction PM2.5 largely stems from outdoor air. Accordingly, the German Working Group on Indoor Guideline Values of the Federal Environmental Agency and the States' Health Authorities also recommends WHO's (2006) 24-hour mean guideline value of 25 microg PM2,5 per cubic meter for indoor air evaluation. In contrast to PM2.5, coarse particles (PM10) in schools, kindergartens and dwellings show much higher indoor air concentrations. Additional sources indoors have to be assumed. Because of the different composition of indoor air compared to outdoor air and due to the lack of dose-response relationships of coarse particles in indoor air, the health effects of indoor air PM10 can not be evaluated yet. Sufficient and consistent ventilation is an indispensable basis to reduce PM concentrations in indoor spaces. Furthermore, known sources of PM indoors should be detected consequently and subsequently minimized.

The interaction of fine particles with stranded oil

International Nuclear Information System (INIS)

Owens, E.H.

1999-01-01

The interaction of micron-sized mineral particles with stranded oil reduces its adhesion to solid surfaces, such as sediments or bedrock. The net result is the formation of stable, micron-sized, oil droplets that disperse into the water column. In turn, the increase in surface area makes the oil more available for biodegradation. Oil and Fine-particle Interaction ('OFI') can explain how oiled shorelines are cleaned naturally in the absence of wave action in very sheltered coastal environments. Fine-particle interaction can be accelerated during a spill response by relocating the oiled sediments into the surf zone. This has been achieved successfully on two occasions to date: the Tampa Bay response in Florida, and the Sea Empress operation in Wales. Sediment relocation also causes physical abrasion by the hydraulic action of waves so that the processes of fine-particle interaction and surf washing usually occur in combination on open coasts. (author)

Fractal aggregation and breakup of fine particles

Directory of Open Access Journals (Sweden)

Li Bingru

2016-01-01

Full Text Available Breakup may exert a controlling influence on particle size distributions and particles either are fractured or are eroded particle-by-particle through shear. The shear-induced breakage of fine particles in turbulent conditions is investigated using Taylor-expansion moment method. Their equations have been derived in continuous form in terms of the number density function with particle volume. It suitable for future implementation in computational fluid dynamics modeling.

Innovations in the flotation of fine and coarse particles

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Fornasiero, D.; Filippov, L. O.

2017-07-01

Research on the mechanisms of particle-bubble interaction has provided valuable information on how to improve the flotation of fine (100 µm) with novel flotation machines which provide higher collision and attachment efficiencies of fine particles with bubbles and lower detachment of the coarse particles. Also, new grinding methods and technologies have reduced energy consumption in mining and produced better mineral liberation and therefore flotation performance.

On the Accelerated Settling of Fine Particles in a Bidisperse Slurry

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Leonid L. Minkov

2015-01-01

Full Text Available An estimation of increasing the volume average sedimentation velocity of fine particles in bidisperse suspension due to their capturing in the circulation zone formed in the laminar flow of incompressible viscous fluid around the spherical coarse particle is proposed. The estimation is important for an explanation of the nonmonotonic shape of the separation curve observed for hydrocyclones. The volume average sedimentation velocity is evaluated on the basis of a cellular model. The characteristic dimensions of the circulation zone are obtained on the basis of a numerical solution of Navier-Stokes equations. Furthermore, these calculations are used for modelling the fast sedimentation of fine particles during their cosedimentation in bidisperse suspension. It was found that the acceleration of sedimentation of fine particles is determined by the concentration of coarse particles in bidisperse suspension, and the sedimentation velocity of fine fraction is proportional to the square of the coarse and fine particle diameter ratio. The limitations of the proposed model are ascertained.

A hazard to health? Fine particles arouse worldwide interest

Energy Technology Data Exchange (ETDEWEB)

Karas, J; Oesch, P

1998-07-01

The most recent studies show that particles contained in the air that we breathe may have harmful effects on the health of asthmatics, children and old people in particular. Particle material found in ambient air is formed by emissions resulting from traffic, industry and other use of fuels. Nature`s own sources also have a significant effect on particle concentrations. The mechanisms by which fine particles may produce negative health effects are so far unknown. At present it is therefore impossible to assess the effects of emissions of fine particles resulting, for instance, from the use of fossil fuels

IBA and synchrotron methods for sub-micron fine particle characterisation

International Nuclear Information System (INIS)

Cohen, D.D.; Siegele, R. Stampfl. A.; Cai, Z.; Ilinski, P.; Rodrigues, W.; Legnini, D.G.; Yun, W.; Lai, B.

1999-01-01

Fine air-borne particles, whose average diameters are 2.5 μm and less (PM2.5), are known to play significant roles in a number of human and environmental issues. They may penetrate deep into the human lung system and are believed, due to their small size or due to toxins adsorbed onto their surfaces, to be responsible for up to 60,000 and 10,000 deaths in the U.S. and U.K. respectively. Health studies within NSW, Australia carried out by the NSW EPA, have shown increased hospital admissions and excess deaths related to high fine particle pollution episodes. A number of environmental issues are affected by the amount and type of fine-particles in the air. The white and brown hazes that occur in populated cities causing poor visibility are due to light scattering from fine particles. These same particles are easily transported large distances in the lower atmosphere playing a key role in global pollution and climate forcing. Current knowledge of fine-particle concentrations and constituents is very limited. Sources of fine particles are both natural and man-made. Over the past few years considerable work on the characterisation of these particles has been going on at ANSTO using accelerator based ion beam analysis (IBA) methods. X-ray fluorescence using ion beams from accelerators and synchrotron fluorescence are complementary techniques. This is well demonstrated by the plot. PIXE has higher cross sections for low Z elements, but for high Z elements closer to the excitation energy (16keV) synchrotron radiation cross sections are larger. Both techniques are multi-elemental analysis techniques

Relationships of outdoor and indoor ultrafine particles at residences downwind of a major international border crossing in Buffalo, NY.

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McAuley, T R; Fisher, R; Zhou, X; Jaques, P A; Ferro, A R

2010-08-01

During winter 2006, indoor and outdoor ultrafine particle (UFP) size distribution measurements for particles with diameters from 5.6 to 165 nm were taken at five homes in a neighborhood directly adjacent to the Peace Bridge Complex (PBC), a major international border crossing connecting Buffalo, New York to Fort Erie, Ontario. Monitoring with 1-s time resolution was conducted for several hours at each home. Participants were instructed to keep all external windows and doors closed and to refrain from cooking, smoking, or other activity that may result in elevating the indoor UFP number concentration. Although the construction and age for the homes were similar, indoor-to-outdoor comparisons indicate that particle infiltration rates varied substantially. Overall, particle concentrations indoors were lower and less variable than particle concentrations outdoors, with average indoor-outdoor ratios ranging from 0.1 to 0.5 (mean 0.34) for particles between 5.6 and 165 nm in diameter. With no indoor sources, the average indoor-outdoor ratios were lowest (0.2) for 20-nm particles, higher (0.3) for particles <10 nm, and highest (0.5) for particles 70-165 nm. This study provides insight into the penetration of UFP into homes and the resulting change in particle size distributions as particles move indoors near a major diesel traffic source. Although people spend most of their time in their homes, exposure estimates for epidemiological studies are generally determined using ambient concentrations. The findings of this study will contribute to improved size-resolved UFP exposure estimates for near roadway exposure assessments and epidemiological studies.

Number Concentrations and Modal Structure of Indoor/Outdoor Fine Particles in Four European Cities.

Czech Academy of Sciences Publication Activity Database

Lazaridis, M.; Eleftheriadis, K.; Ždímal, Vladimír; Schwarz, Jaroslav; Wagner, Zdeněk; Ondráček, Jakub; Drossinos, Y.; Glytsos, T.; Vratolis, S.; Torseth, K.; Moravec, Pavel; Hussein, T.; Smolík, Jiří

2017-01-01

Roč. 17, č. 1 (2017), s. 131-146 ISSN 1680-8584 EU Projects: European Commission(XE) 315760 - HEXACOMM Institutional support: RVO:67985858 Keywords : indoor/outdoor aerosol * I/O ratio * modal structure Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 2.606, year: 2016

Spatial and indoor/outdoor gradients in urban concentrations of ultrafine particles and PM2.5 mass and chemical components

Science.gov (United States)

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.

Risk of pneumonia in obstructive lung disease: A real-life study comparing extra-fine and fine-particle inhaled corticosteroids.

Science.gov (United States)

Sonnappa, Samatha; Martin, Richard; Israel, Elliot; Postma, Dirkje; van Aalderen, Wim; Burden, Annie; Usmani, Omar S; Price, David B

2017-01-01

Regular use of inhaled corticosteroids (ICS) in patients with obstructive lung diseases has been associated with a higher risk of pneumonia, particularly in COPD. The risk of pneumonia has not been previously evaluated in relation to ICS particle size and dose used. Historical cohort, UK database study of 23,013 patients with obstructive lung disease aged 12-80 years prescribed extra-fine or fine-particle ICS. The endpoints assessed during the outcome year were diagnosis of pneumonia, acute exacerbations and acute respiratory events in relation to ICS dose. To determine the association between ICS particle size, dose and risk of pneumonia in unmatched and matched treatment groups, logistic and conditional logistic regression models were used. 14788 patients were stepped-up to fine-particle ICS and 8225 to extra-fine ICS. On unmatched analysis, patients stepping-up to extra-fine ICS were significantly less likely to be coded for pneumonia (adjusted odds ratio [aOR] 0.60; 95% CI 0.37, 0.97]); experience acute exacerbations (adjusted risk ratio [aRR] 0.91; 95%CI 0.85, 0.97); and acute respiratory events (aRR 0.90; 95%CI 0.86, 0.94) compared with patients stepping-up to fine-particle ICS. Patients prescribed daily ICS doses in excess of 700 mcg (fluticasone propionate equivalent) had a significantly higher risk of pneumonia (OR [95%CI] 2.38 [1.17, 4.83]) compared with patients prescribed lower doses, irrespective of particle size. These findings suggest that patients with obstructive lung disease on extra-fine particle ICS have a lower risk of pneumonia than those on fine-particle ICS, with those receiving higher ICS doses being at a greater risk.

The influences of ambient particle composition and size on particle infiltration in Los Angeles, CA, residences.

Science.gov (United States)

Sarnat, Stefanie Ebelt; Coull, Brent A; Ruiz, Pablo A; Koutrakis, Petros; Suh, Helen H

2006-02-01

Particle infiltration is a key determinant of the indoor concentrations of ambient particles. Few studies have examined the influence of particle composition on infiltration, particularly in areas with high concentrations of volatile particles, such as ammonium nitrate (NH4NO3). A comprehensive indoor monitoring study was conducted in 17 Los Angeles-area homes. As part of this study, indoor/outdoor concentration ratios during overnight (nonindoor source) periods were used to estimate the fraction of ambient particles remaining airborne indoors, or the particle infiltration factor (FINF), for fine particles (PM2.5), its nonvolatile (i.e., black carbon [BC]) and volatile (i.e., nitrate [NO3-]) components, and particle sizes ranging between 0.02 and 10 microm. FINF was highest for BC (median = 0.84) and lowest for NO3- (median = 0.18). The low FINF for NO3- was likely because of volatilization of NO3- particles once indoors, in addition to depositional losses upon building entry. The FINF for PM2.5 (median = 0.48) fell between those for BC and NO3-, reflecting the contributions of both particle components to PM25. FINF varied with particle size, air-exchange rate, and outdoor NO3- concentrations. The FINF for particles between 0.7 and 2 microm in size was considerably lower during periods of high as compared with low outdoor NO3- concentrations, suggesting that outdoor NO3- particles were of this size. This study demonstrates that infiltration of PM2.5 varies by particle component and is lowest for volatile species, such as NH4NO3. Our results suggest that volatile particle components may influence the ability for outdoor PM concentrations to represent indoor and, thus, personal exposures to particles of ambient origin, because volatilization of these particles causes the composition of PM2.5 to differ indoors and outdoors. Consequently, particle composition likely influences observed epidemiologic relationships based on outdoor PM concentrations, especially in areas

Health impact of exposure to fine particles. Epidemiology of short-term effects

International Nuclear Information System (INIS)

Peters, Annette; Wichmann, H.-Erich; Univ. Muenchen; Heinrich, Joachim

2002-01-01

Epidemiological studies on short-term effects of fine particles are investigating whether morbidity or mortality increase on days with high particle concentrations. Multi-center studies have shown on a daily basis that there is an increase in morbidity and/or mortality in association with particle concentrations. Studies on the effects of particles on the respiratory tract have indicated that there is an impact of particles at their place of deposition. In addition, numerous studies have revealed that particles also have effects on the cardiovascular system, including acute-phase reactions, increased hospital admissions, and also an increase in cardiovascular disease mortality in association with elevated particle concentrations. For PM 10 consistent effects were found. Furthermore, the analyses showed that no threshold value could be established, but a linear dose-effect relation. Studies measuring PM 2.5 point to fine particles being mainly responsible for these effects. Current studies show that in addition to fine particles, ultra-fine particles can cause further health effects. (orig.) [de

Indoor and outdoor sources of size-resolved mass concentration of particulate matter in a school gym-implications for exposure of exercising children.

Science.gov (United States)

Braniš, Martin; Safránek, Jiří; Hytychová, Adéla

2011-05-01

It has been noticed many times that schools are buildings with high levels of particulate matter concentrations. Several authors documented that concentrations of particulate matter in indoor school microenvironments exceed limits recommended by WHO namely when school buildings are situated near major roads with high traffic densities. In addition, exercise under conditions of high particulate concentrations may increase the adverse health effects, as the total particle deposition increases in proportion to minute ventilation, and the deposition fraction nearly doubles from rest to intense exercise. Mass concentrations of size-segregated aerosol were measured simultaneously in an elementary school gym and an adjacent outdoor site in the central part of Prague by two pairs of collocated aerosol monitors-a fast responding photometer DusTrak and a five stage cascade impactor. To encompass seasonal and annual differences, 89 days of measurements were performed during ten campaigns between 2005 and 2009. The average (all campaigns) outdoor concentration of PM(2.5) (28.3 μg m(-3)) measured by the cascade impactors was higher than the indoor value (22.3 μg m(-3)) and the corresponding average from the nearest fixed site monitor (23.6 μg m(-3)). Indoor and outdoor PM(2.5) concentrations exceeded the WHO recommended 24-h limit in 42% and 49% of the days measured, respectively. The correlation coefficient (r) between corresponding outdoor and indoor aerosol sizes increased with decreasing aerodynamic diameter of the collected particles (r = 0.32-0.87), suggesting a higher infiltration rate of fine and quasi-ultrafine particles. Principal component analysis revealed five factors explaining more than 82% of the data variability. The first two factors reflected a close association between outdoor and indoor fine and quasi-ultrafine particles confirming the hypothesis of high infiltration rate of particles from outdoors. The third factor indicated that human

Sintering of Fine Particles in Suspension Plasma Sprayed Coatings

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Leszek Latka

2010-07-01

Full Text Available Suspension plasma spraying is a process that enables the production of finely grained nanometric or submicrometric coatings. The suspensions are formulated with the use of fine powder particles in water or alcohol with some additives. Subsequently, the suspension is injected into plasma jet and the liquid additives evaporate. The remaining fine solids are molten and subsequently agglomerate or remain solid, depending on their trajectory in the plasma jet. The coating’s microstructure results from these two groups of particles arriving on a substrate or previously deposited coating. Previous experimental studies carried out for plasma sprayed titanium oxide and hydroxyapatite coatings enabled us to observe either a finely grained microstructure or, when a different suspension injection mode was used, to distinguish two zones in the microstructure. These two zones correspond to the dense zone formed from well molten particles, and the agglomerated zone formed from fine solid particles that arrive on the substrate in a solid state. The present paper focuses on the experimental and theoretical analysis of the formation process of the agglomerated zone. The experimental section establishes the heat flux supplied to the coating during deposition. In order to achieve this, calorimetric measurements were made by applying experimental conditions simulating the real coatings’ growth. The heat flux was measured to be in the range from 0.08 to 0.5 MW/m2,depending on the experimental conditions. The theoretical section analyzes the sintering during the coating’s growth, which concerns the fine particles arriving on the substrate in the solid state. The models of volume, grain boundary and surface diffusion were analyzed and adapted to the size and chemistry of the grains, temperature and time scales corresponding to the suspension plasma spraying conditions. The model of surface diffusion was found to best describe the sintering during suspension

Prediction of indoor concentration of 0.5-4 µm particles of outdoor origin in an uninhabited apartment

DEFF Research Database (Denmark)

Schneider, T.; Jensen, K.A.; Clausen, P.A.

2004-01-01

Indoor and outdoor particle size distributions, indoor-outdoor pressure difference, indoor air-exchange rate, and meteorological conditions were measured at an uninhabited apartment located in a busy street in Copenhagen during 1-month long fall, winter and spring campaigns. Particle penetration...... was estimated from concentration rebound measurements following HEPA filtering of the indoor air by fitting a simple deterministic model. The model included measured air exchange rates and published surface deposition loss rates. This model was then used to predict indoor particle concentration. The model...

EFFECT OF BODY SIZE ON BREATHING PATTERN AND FINE PARTICLE DEPOSITION IN CHILDREN

Science.gov (United States)

Inter-child variability in breathing patterns may contribute to variability in fine particle, lung deposition and morbidity in children associated with those particles. Fractional deposition (DF) of fine particles (2um monodisperse, carnauba wax particles) was measured in healthy...

Outdoor ultrafine particle concentrations in front of fast food restaurants.

Science.gov (United States)

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.

Removal of fine particles in wet flue gas desulfurization system by heterogeneous condensation

Energy Technology Data Exchange (ETDEWEB)

Yang, L.J.; Bao, J.J.; Yan, J.P.; Liu, J.H.; Song, S.J.; Fan, F.X. [Southeast University, Nanjing (China). School of Energy & Environment

2010-01-01

A novel process to remove fine particles with high efficiency by heterogeneous condensation in a wet flue gas desulfurization (WFGD) system is presented. A supersaturated vapor phase, necessary for condensational growth of fine particles, was achieved in the SO{sub 2} absorption zone and at the top of the wet FGD scrubber by adding steam in the gas inlet and above the scrubbing liquid inlet of the scrubber, respectively. The condensational grown droplets were then removed by the scrubbing liquid and a high-efficiency demister. The results show that the effectiveness of the WFGD system for removal of fine particles is related to the SO{sub 2} absorbent employed. When using CaCO{sub 3} and NH{sub 3} {center_dot} H{sub 2}O to remove SO{sub 2} from flue gas, the fine particle removal efficiencies are lower than those for Na2CO{sub 3} and water, and the morphology and elemental composition of fine particles are changed. This effect can be attributed to the formation of aerosol particles in the limestone and ammonia-based FGD processes. The performance of the WFGD system for removal of fine particles can be significantly improved for both steam addition cases, for which the removal efficiency increases with increasing amount of added steam. A high liquid to gas ratio is beneficial for efficient removal of fine particles by heterogeneous condensation of water vapor.

Association of fine particles with respiratory disease mortality: a meta-analysis.

Science.gov (United States)

Chang, Xuhong; Zhou, Liangjia; Tang, Meng; Wang, Bei

2015-01-01

Short-time exposure to high levels of fine particles (particulate matter with an aerodynamic diameter≤2.5 μm; PM2.5) may trigger respiratory disease, but this association has not been determined. The objective of this study was to evaluate and quantify the short-time exposure to fine particles on respiratory disease mortality. Published articles were obtained from electronic databases and a validity assessment was used. The meta-analysis was conducted with the incorporation of good-quality studies. After applying the inclusion criteria, 9 articles were included in the study. The methodological qualities of the published studies were good, and every study achieved a score of 3. Fine particles were significantly associated with an increase in respiratory mortality risk (for every 10 μg/m3 increment, rate difference [RD]=1.32%, 95% confidence interval [CI]: 0.95%-1.68%; p=.000). These findings indicate that short-time exposure to fine particles could increase the risk of respiratory disease mortality.

THE INFLUENCE OF BUILDING FEATURES ON AIR EXCHANGE RATE AND PARTICLE PENETRATION

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The paper discusses some measured values of particle penetration into an unoccupied research house under a variety of conditions. (NOTE: Exposure to fine particles of outdoor origin continues to receive increased attention. Since people spend up to 90% of their time indoors, the ...

Asthma-Related Outcomes in Patients Initiating Extrafine Ciclesonide or Fine-Particle Inhaled Corticosteroids

Science.gov (United States)

Postma, Dirkje S.; Dekhuijzen, Richard; van der Molen, Thys; Martin, Richard J.; van Aalderen, Wim; Roche, Nicolas; Guilbert, Theresa W.; Israel, Elliot; van Eickels, Daniela; Khalid, Javaria Mona; Herings, Ron M.C.; Overbeek, Jetty A.; Miglio, Cristiana; Thomas, Victoria; Hutton, Catherine; Hillyer, Elizabeth V.

2017-01-01

Purpose Extrafine-particle inhaled corticosteroids (ICS) have greater small airway deposition than standard fine-particle ICS. We sought to compare asthma-related outcomes after patients initiated extrafine-particle ciclesonide or fine-particle ICS (fluticasone propionate or non-extrafine beclomethasone). Methods This historical, matched cohort study included patients aged 12-60 years prescribed their first ICS as ciclesonide or fine-particle ICS. The 2 cohorts were matched 1:1 for key demographic and clinical characteristics over the baseline year. Co-primary endpoints were 1-year severe exacerbation rates, risk-domain asthma control, and overall asthma control; secondary endpoints included therapy change. Results Each cohort included 1,244 patients (median age 45 years; 65% women). Patients in the ciclesonide cohort were comparable to those in the fine-particle ICS cohort apart from higher baseline prevalence of hospitalization, gastroesophageal reflux disease, and rhinitis. Median (interquartile range) prescribed doses of ciclesonide and fine-particle ICS were 160 (160-160) µg/day and 500 (250-500) µg/day, respectively (P<0.001). During the outcome year, patients prescribed ciclesonide experienced lower severe exacerbation rates (adjusted rate ratio [95% CI], 0.69 [0.53-0.89]), and higher odds of risk-domain asthma control (adjusted odds ratio [95% CI], 1.62 [1.27-2.06]) and of overall asthma control (2.08 [1.68-2.57]) than those prescribed fine-particle ICS. The odds of therapy change were 0.70 (0.59-0.83) with ciclesonide. Conclusions In this matched cohort analysis, we observed that initiation of ICS with ciclesonide was associated with better 1-year asthma outcomes and fewer changes to therapy, despite data suggesting more difficult-to-control asthma. The median prescribed dose of ciclesonide was one-third that of fine-particle ICS. PMID:28102056

Indoor-outdoor concentrations of fine particulate matter in school building microenvironments near a mine tailing deposit

Directory of Open Access Journals (Sweden)

Leonardo Martínez

2016-11-01

Full Text Available Indoor air quality in school classrooms is a major pediatric health concern because children are highly susceptible to adverse effects from xenobiotic exposure. Fine particulate matter (PM2.5 emitted from mining waste deposits within and near cities in northern Chile is a serious environmental problem. We measured PM2.5 in school microenvironments in urban areas of Chañaral, a coastal community whose bay is contaminated with mine tailings. PM2.5 levels were measured in six indoor and outdoor school environments during the summer and winter of 2012 and 2013. Measurements were taken during school hours on two consecutive days. Indoor PM2.5 concentrations were 12.53–72.38 μg/m3 in the summer and 21.85–100.53 μg/m3 in winter, while outdoor concentrations were 11.86–181.73 μg/m3 in the summer and 21.50–93.07 μg/m3 in winter. Indoor/outdoor ratios were 0.17–2.76 in the summer and 0.64–4.49 in winter. PM2.5 levels were higher in indoor microenvironments during the winter, at times exceeding national and international recommendations. Our results demonstrate that indoor air quality Chañaral school microenvironments is closely associated with outdoor air pollution attributable to the nearby mine tailings. Policymakers should enact environmental management strategies to minimize further environmental damage and mitigate the risks that this pollution poses for pediatric health.

Reduction of fine airborne particulates (PM3) in a small city centre office, by altering electrostatic forces.

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Richardson, G; Harwood, D J; Eick, S A; Dobbs, F; Rosén, K G

2001-03-26

A two stage intervention study was carried out to establish the degree to which a newly developed, electrostatic air cleaning (EAC) system can improve indoor air quality (IAQ) by reducing the number of airborne fine particles. The IAQ and how employees in a city centre office (49 m2) perceived it, was monitored from May until November 1998. The number of fine particles, PM3 (0.3-3.0 microm); number of coarse particles, PM7 (3.0-7.0 microm); number of small positive and negative air ions; relative humidity and temperature were recorded in and out of doors. To assess the employees' perception of any changes in their work environment, a questionnaire was completed. Number of particles, relative humidity and temperature were also recorded in a nearby office, equipped with an identical air processor, where no interventions were made. The results from the first intervention (Stage 1), comparing number of airborne particles outdoors to indoors, gave a 19% reduction for PM3 and a 67% reduction for PM7 (P PM7 from outdoors and the removal of PM7 created indoors was achieved by optimizing the existing air moving equipment. The results from the second intervention (Stage 2--with EAC units installed) comparing indoor to outdoor values, gave a further reduction in PM3 of 21% (P PM7 (P > 0.05). Therefore, at the end of Stage 2, the total reductions in particles from outdoors to indoors were 40% for PM3 and 70% for PM7 (P PM7. The questionnaire indicated an improvement in the IAQ, as perceived by the employees. The results suggest that the EAC system is effective in reducing PM3 and thereby improving IAQ in an urban office.

Coupling Solute and Fine Particle Transport with Sand Bed Morphodynamics within a Field Experiment

Science.gov (United States)

Phillips, C. B.; Ortiz, C. P.; Schumer, R.; Jerolmack, D. J.; Packman, A. I.

2017-12-01

Fine suspended particles are typically considered to pass through streams and rivers as wash load without interacting with the bed, however experiments have demonstrated that hyporheic flow causes advective exchange of fine particles with the stream bed, yielding accumulation of fine particle deposits within the bed. Ultimately, understanding river morphodynamics and ecosystem dynamics requires coupling both fine particle and solute transport with bed morphodynamics. To better understand the coupling between these processes we analyze a novel dataset from a controlled field experiment conducted on Clear Run, a 2nd order sand bed stream located within the North Carolina coastal plain. Data include concentrations of continuously injected conservative solutes and fine particulate tracers measured at various depths within the stream bed, overhead time lapse images of bed forms, stream discharge, and geomorphological surveys of the stream. We use image analysis of bed morphodynamics to assess exchange, retention, and remobilization of solutes and fine particles during constant discharge and a short duration experimental flood. From the images, we extract a time series of bedform elevations and scour depths for the duration of the experiment. The high-resolution timeseries of bed elevation enables us to assess coupling of bed morphodynamics with both the solute and fine particle flux during steady state mobile bedforms prior to the flood and to changing bedforms during the flood. These data allow the application of a stochastic modeling framework relating bed elevation fluctuations to fine particle residence times. This combined experimental and modeling approach ultimately informs our ability to predict not only the fate of fine particulate matter but also associated nutrient and carbon dynamics within streams and rivers.

Indoor and Outdoor Levels and Sources of Submicron Particles (PM1) at Homes in Edmonton, Canada.

Science.gov (United States)

Bari, Md Aynul; Kindzierski, Warren B; Wallace, Lance A; Wheeler, Amanda J; MacNeill, Morgan; Héroux, Marie-Ève

2015-06-02

Exposure to submicron particles (PM1) is of interest due to their possible chronic and acute health effects. Seven consecutive 24-h PM1 samples were collected during winter and summer 2010 in a total of 74 nonsmoking homes in Edmonton, Canada. Median winter concentrations of PM1 were 2.2 μg/m(3) (interquartile range, IQR = 0.8-6.1 μg/m(3)) and 3.3 μg/m(3) (IQR = 1.5-6.9 μg/m(3)) for indoors and outdoors, respectively. In the summer, indoor (median 4.4 μg/m(3), IQR = 2.4-8.6 μg/m(3)) and outdoor (median 4.3 μg/m(3), IQR = 2.6-7.4 μg/m(3)) levels were similar. Positive matrix factorization (PMF) was applied to identify and apportion indoor and outdoor sources of elements in PM1 mass. Nine sources contributing to both indoor and outdoor PM1 concentrations were identified including secondary sulfate, soil, biomass smoke and environmental tobacco smoke (ETS), traffic, settled and mixed dust, coal combustion, road salt/road dust, and urban mixture. Three additional indoor sources were identified i.e., carpet dust, copper-rich, and silver-rich. Secondary sulfate, soil, biomass smoke and ETS contributed more than 70% (indoors: 0.29 μg/m(3), outdoors: 0.39 μg/m(3)) of measured elemental mass in PM1. These findings can aid understanding of relationships between submicron particles and health outcomes for indoor/outdoor sources.

Characterization of particle number concentrations and PM2.5 in a school: influence of outdoor air pollution on indoor air.

Science.gov (United States)

Guo, Hai; Morawska, Lidia; He, Congrong; Zhang, Yanli L; Ayoko, Godwin; Cao, Min

2010-07-01

The impact of air pollution on school children's health is currently one of the key foci of international and national agencies. Of particular concern are ultrafine particles which are emitted in large quantities, contain large concentrations of toxins and are deposited deeply in the respiratory tract. In this study, an intensive sampling campaign of indoor and outdoor airborne particulate matter was carried out in a primary school in February 2006 to investigate indoor and outdoor particle number (PN) and mass concentrations (PM(2.5)), and particle size distribution, and to evaluate the influence of outdoor air pollution on the indoor air. For outdoor PN and PM(2.5), early morning and late afternoon peaks were observed on weekdays, which are consistent with traffic rush hours, indicating the predominant effect of vehicular emissions. However, the temporal variations of outdoor PM(2.5) and PN concentrations occasionally showed extremely high peaks, mainly due to human activities such as cigarette smoking and the operation of mower near the sampling site. The indoor PM(2.5) level was mainly affected by the outdoor PM(2.5) (r = 0.68, p changes to the modal structure of particle number and size distribution, even though the I/O ratio was different for different size classes. The I/O curves had a maximum value for particles with diameters of 100-400 nm under both occupied and unoccupied scenarios, whereas no significant difference in I/O ratio for PM(2.5) was observed between occupied and unoccupied conditions. Inspection of the size-resolved I/O ratios in the preschool centre and the classroom suggested that the I/O ratio in the preschool centre was the highest for accumulation mode particles at 600 nm after school hours, whereas the average I/O ratios of both nucleation mode and accumulation mode particles in the classroom were much lower than those of Aitken mode particles. The findings obtained in this study are useful for epidemiological studies to estimate the

Role of hydrotreating products in deposition of fine particles in reactors

Energy Technology Data Exchange (ETDEWEB)

Wang, S.; Chung, K.; Gray, M.R. [University of Alberta, Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

2001-06-11

Hydrotreating reactions may affect the deposition of fine particles, which can eventually lead to reactor plugging. The deposition of fine particles from gas oil was measured in an internally recirculating reactor at 375{degree}C under hydrogen. H{sub 2}S from hydrodesulfurization would convert corrosion products to metal sulfides. Iron sulfide deposited rapidly in the packed bed because the mineral surface did not retain a stabilizing layer of asphaltenic material. Addition of water, to test the role of hydrodeoxygenation, doubled the deposition of clay particles by reducing the surface coating of organic material. Neither ammonia or quinoline had any effect on particle deposition, therefore, hydrodenitrogenation did not affect particle behavior. 16 refs., 4 figs., 3 tabs.

Atmospheric fate and transport of fine volcanic ash: Does particle shape matter?

Science.gov (United States)

White, C. M.; Allard, M. P.; Klewicki, J.; Proussevitch, A. A.; Mulukutla, G.; Genareau, K.; Sahagian, D. L.

2013-12-01

Volcanic ash presents hazards to infrastructure, agriculture, and human and animal health. In particular, given the economic importance of intercontinental aviation, understanding how long ash is suspended in the atmosphere, and how far it is transported has taken on greater importance. Airborne ash abrades the exteriors of aircraft, enters modern jet engines and melts while coating interior engine parts causing damage and potential failure. The time fine ash stays in the atmosphere depends on its terminal velocity. Existing models of ash terminal velocities are based on smooth, quasi-spherical particles characterized by Stokes velocity. Ash particles, however, violate the various assumptions upon which Stokes flow and associated models are based. Ash particles are non-spherical and can have complex surface and internal structure. This suggests that particle shape may be one reason that models fail to accurately predict removal rates of fine particles from volcanic ash clouds. The present research seeks to better parameterize predictive models for ash particle terminal velocities, diffusivity, and dispersion in the atmospheric boundary layer. The fundamental hypothesis being tested is that particle shape irreducibly impacts the fate and transport properties of fine volcanic ash. Pilot studies, incorporating modeling and experiments, are being conducted to test this hypothesis. Specifically, a statistical model has been developed that can account for actual volcanic ash size distributions, complex ash particle geometry, and geometry variability. Experimental results are used to systematically validate and improve the model. The experiments are being conducted at the Flow Physics Facility (FPF) at UNH. Terminal velocities and dispersion properties of fine ash are characterized using still air drop experiments in an unconstrained open space using a homogenized mix of source particles. Dispersion and sedimentation dynamics are quantified using particle image

Characteristics of fine and coarse particles of natural and urban aerosols of Brazil

International Nuclear Information System (INIS)

Orsini, C.M.Q.; Tabacniks, M.H.; Artaxo Netto, P.E.; Andrade, M.F.; Kerr, A.

1986-02-01

Fine and coarse particles have been sampled from 1982 to 1985 in one natural forest seacoast site (Jureia) and five urban-industrial cities (Vitoria, Salvador, Porto Alegre, Sao Paulo, and Belo Horizonte). The time variations of concentrations in air and the relative elemental compositions of fine and coarse particle fractions, sampled by Nuclepore stacked filter units (SFU), have been determined gravimetrically and by PIXE analysis, respectively. Enrichment factors and correlation coefficients of the trace elements measured lead to unambiguous characterization of soil dust and sea salt, both major aerosol sources that emit coarse particles, and soil dust is also a significant source of fine particles. (Author) [pt

Dynamic Simulation of Random Packing of Polydispersive Fine Particles

Science.gov (United States)

Ferraz, Carlos Handrey Araujo; Marques, Samuel Apolinário

2018-02-01

In this paper, we perform molecular dynamic (MD) simulations to study the two-dimensional packing process of both monosized and random size particles with radii ranging from 1.0 to 7.0 μm. The initial positions as well as the radii of five thousand fine particles were defined inside a rectangular box by using a random number generator. Both the translational and rotational movements of each particle were considered in the simulations. In order to deal with interacting fine particles, we take into account both the contact forces and the long-range dispersive forces. We account for normal and static/sliding tangential friction forces between particles and between particle and wall by means of a linear model approach, while the long-range dispersive forces are computed by using a Lennard-Jones-like potential. The packing processes were studied assuming different long-range interaction strengths. We carry out statistical calculations of the different quantities studied such as packing density, mean coordination number, kinetic energy, and radial distribution function as the system evolves over time. We find that the long-range dispersive forces can strongly influence the packing process dynamics as they might form large particle clusters, depending on the intensity of the long-range interaction strength.

Fine particles in the Soufriere eruption plume

Science.gov (United States)

Woods, D. C.; Chuan, R. L.

1982-01-01

The size distributions of fine particles measured at tropospheric altitudes in the periphery of the eruption plume formed during the April 17, 1979 eruption of Soufriere Volcano and in the low-level effluents on May 15, 1979 were found to be bimodal, having peak concentrations at geometric mean diameters of 1.1 and 0.23 micrometers. Scanning electron microscopy and energy-dispersive X-ray analysis of the samples revealed an abundance of aluminum and silicon and traces of sodium, magnesium, chlorine, potassium, calcium, and iron in the large-particle mode. The submicrometer-sized particles were covered with liquid containing sulfur, assumed to be in the form of liquid sulfuric acid.

Computer Models Simulate Fine Particle Dispersion

Science.gov (United States)

2010-01-01

Through a NASA Seed Fund partnership with DEM Solutions Inc., of Lebanon, New Hampshire, scientists at Kennedy Space Center refined existing software to study the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces. The software, EDEM, allows users to import particles and obtain accurate representations of their shapes for modeling purposes, such as simulating bulk solids behavior, and was enhanced to be able to more accurately model fine, abrasive, cohesive particles. These new EDEM capabilities can be applied in many industries unrelated to space exploration and have been adopted by several prominent U.S. companies, including John Deere, Pfizer, and Procter & Gamble.

Measurement of fine particles and smoking activity in a statewide survey of 36 California Indian casinos

Science.gov (United States)

Jiang, Ru O-Ting; Cheng, Ka I-Chung; Acevedo-Bolton, Viviana; Klepeis, Neil E; Repace, James L; Ott, Wayne R; Hildemann, Lynn M

2011-01-01

Despite California's 1994 statewide smoking ban, exposure to secondhand smoke (SHS) continues in California's Indian casinos. Few data are available on exposure to airborne fine particles (PM2.5) in casinos, especially on a statewide basis. We sought to measure PM2.5 concentrations in Indian casinos widely distributed across California, exploring differences due to casino size, separation of smoking and non-smoking areas, and area smoker density. A selection of 36 out of the 58 Indian casinos throughout California were each visited for 1–3 h on weekend or holiday evenings, using two or more concealed monitors to measure PM2.5 concentrations every 10 s. For each casino, the physical dimensions and the number of patrons and smokers were estimated. As a preliminary assessment of representativeness, we also measured eight casinos in Reno, NV. The average PM2.5 concentration for the smoking slot machine areas (63 μg/m3) was nine times as high as outdoors (7 μg/m3), whereas casino non-smoking restaurants (29 μg/m3) were four times as high. Levels in non-smoking slot machine areas varied: complete physical separation reduced concentrations almost to outdoor levels, but two other separation types had mean levels that were 13 and 29 μg/m3, respectively, higher than outdoors. Elevated PM2.5 concentrations in casinos can be attributed primarily to SHS. Average PM2.5 concentrations during 0.5–1 h visits to smoking areas exceeded 35 μg/m3 for 90% of the casino visits. PMID:20160761

The Effect Of Fine Particle Migration On Void Ratio Of Gap Graded Soil

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Mayssa Salem Flayh

2017-12-01

Full Text Available Soil is exposed to the migration of fine particles in some cases because of some conditions including excavation and the presence of a level of groundwater which is equal to the level of soil in this case and because of the existence of this water leakage which would work on the migration of fine particles in the soil. This migration of fine particles will change the structure of the soil and change its properties. In this study we will know the change in the properties of the fouling soil due to the migration of fine particles and four types of soil. The first type does not contain fine particles and the second type the third and the fourth contains 10 20 30 granules respectively and tests were carried out for these soils Atterberg limits sieve analysis specific gravity shear resistance permeability modified Procter consolidation. A model was created to simulate the reality of soil exposed to excavations. Three levels were selected in the model to compare the results of each of the four soils under study. The total number of models 24 model through laboratory work obtained the initial and final voids ratio before and after aft the initial and final voids ratio er the particles migration. After these tests it was found that the migration of granules clearly affects the increase in the voids ratio.

Fine Particle Matter (PM2.5) Design Value

Data.gov (United States)

U.S. Environmental Protection Agency — Fine particulate matter or PM2.5 (total mass of particles below 2.5 micron is diameter) is known to cause adverse health effects in humans.See the following websites...

Performance of a New Fine Particle Impact Damper

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Yanchen Du

2008-01-01

Full Text Available The energy dissipation mechanisms of conventional impact damper (CID are mainly momentum exchange and friction. During the impact process, a lot of vibration energy cannot be exhausted but reverberated among the vibration partners. Besides, the CID may produce the additional vibration to the system or even amplify the response in the low-frequency vibration. To overcome these shortcomings, this paper proposes a new fine particle impact damper (FPID which for the first time introduces the fine particle plastic deformation as an irreversible energy sink. Then, the experiments of the cantilevered beam with the CID and that with the FPID are, respectively, carried out to investigate the behavior of FPID. The experimental results indicate that the FPID has a better performance in vibration damping than in the CID and the FPID works well in control of the vibration with frequency lower than 50 Hz, which is absent to the non-obstructive particle damper. Thus, the FPID has a bright and significant application future because most of the mechanical vibration falls in the range of low freqency.

Fine particle magnetic mineralogy of archaeological ceramics

International Nuclear Information System (INIS)

Atkinson, D; King, J A

2005-01-01

This study investigated the magnetic mineralogy of a worldwide collection of archaeological pottery. The mineral types, the mass fractions and the domain states of the constituent magnetic fine particles were elucidated from a range of measurements including magnetic hysteresis behaviour, the acquisition of isothermal remanence, low field susceptibility and thermomagnetic curves. The magnetic mineralogy of most samples was dominated by magnetite. Titanomagnetites with limited titanium substitution and cation deficient magnetites (indicative of low temperature oxidation) were dominant in some samples. Haematite was detected in 53% of the samples, but seldom contributed much to the saturation magnetization. Magnetic particle sizes are skewed to smaller sizes, with sherds mostly having a large superparamagnetic or a stable single domain fraction. Low temperature susceptibility data suggest that 30% of samples had some multidomain component. The percentage by mass of magnetic material in the ancient pottery studied was less than 0.8% for all but one of the samples and the majority of samples contain less than 0.3% by weight of magnetic fine particles. The presence of low temperature oxidation in many samples and the occurrence of a multidomain component in a third of the collection suggest that ancient pottery may not always be suitable for determining the intensity of the ancient geomagnetic field

The dispersion of fine chitosan particles by beads-milling

Science.gov (United States)

Rochima, Emma; Utami, Safira; Hamdani, Herman; Azhary, Sundoro Yoga; Praseptiangga, Danar; Joni, I. Made; Panatarani, Camellia

2018-02-01

This research aimed to produce fine chitosan particles from a crab shell waste by beads-milling method by two different concentration of PEG as dispersing agent (150 and 300 wt. %). The characterization was performed to obtain the size and size distribution, the characteristics of functional groups and the degree of deacetylation. The results showed that the chitosan fine particles was obtained with a milling time 120 minutes with the best concentration of PEG 400 150 wt. %. The average particle size of the as-prepared suspension is 584 nm after addition of acetic acid solution (1%, v/v). Beads milling process did not change the glucosamine and N-acetylglucosamine content on chitosan structure which is indicated by degree of deacetylation higher than 70%. It was concluded that beads milling process can be applied to prepare chitosan fineparticles by proper adjustment in the milling time, pH and dosage of dispersing agent.

The PM2.5 Fine Particle Background Network of the German Meteorological Service-First Results

Directory of Open Access Journals (Sweden)

Uwe Kaminski

2013-04-01

Full Text Available Since 2009, the measurement of the background concentration of the fine particle fraction has been a part of the climate-monitoring program of the German Meteorological Service (DWD. These particles are of high health relevance as a critical air pollutant affecting processes like the scattering and absorption of solar radiation and influencing cloud formation and visibility. At 12 weather stations, the coarse (2.5 to 10 l m and the fine particle fractions (PM2.5 are measured by means of passive and active samplers. First results are presented for the mass concentrations of coarse and fine particles as well as for the black carbon (BC content and the concentration of certain inorganic ions of fine particles. There is not only a seasonal correlation between the fraction of fine and coarse particles, but also a correlation with the location (urban background or rural background. With the help of light microscopy, coarse particles can be differentiated for a geogenic (predominantly wind blown mineral and sea salt particles of natural origin and road abrasion and for an anthropogenic opaque component (combustion residues, e.g. fly ash and non-exhaust vehicle emissions, e.g. abrasion particles of brakes and tires. Measuring the fine fraction and the coarse fraction separately instead of PM10 allows for a better source allocation and thus is a more appropriate method for the improvement of the air quality in, e.g. low emission zones.

Fine particle retention within stream storage areas at base flow and in response to a storm event

Science.gov (United States)

Drummond, J. D.; Larsen, L. G.; González-Pinzón, R.; Packman, A. I.; Harvey, Judson

2017-01-01

Fine particles (1–100 µm), including particulate organic carbon (POC) and fine sediment, influence stream ecological functioning because they may contain or have a high affinity to sorb nitrogen and phosphorus. These particles are immobilized within stream storage areas, especially hyporheic sediments and benthic biofilms. However, fine particles are also known to remobilize under all flow conditions. This combination of downstream transport and transient retention, influenced by stream geomorphology, controls the distribution of residence times over which fine particles influence stream ecosystems. The main objective of this study was to quantify immobilization and remobilization rates of fine particles in a third-order sand-and-gravel bed stream (Difficult Run, Virginia, USA) within different geomorphic units of the stream (i.e., pool, lateral cavity, and thalweg). During our field injection experiment, a thunderstorm-driven spate allowed us to observe fine particle dynamics during both base flow and in response to increased flow. Solute and fine particles were measured within stream surface waters, pore waters, sediment cores, and biofilms on cobbles. Measurements were taken at four different subsurface locations with varying geomorphology and at multiple depths. Approximately 68% of injected fine particles were retained during base flow until the onset of the spate. Retention was evident even after the spate, with 15.4% of the fine particles deposited during base flow still retained within benthic biofilms on cobbles and 14.9% within hyporheic sediment after the spate. Thus, through the combination of short-term remobilization and long-term retention, fine particles can serve as sources of carbon and nutrients to downstream ecosystems over a range of time scales.

Fine particle retention within stream storage areas at base flow and in response to a storm event

Science.gov (United States)

Drummond, J. D.; Larsen, L. G.; González-Pinzón, R.; Packman, A. I.; Harvey, J. W.

2017-07-01

Fine particles (1-100 µm), including particulate organic carbon (POC) and fine sediment, influence stream ecological functioning because they may contain or have a high affinity to sorb nitrogen and phosphorus. These particles are immobilized within stream storage areas, especially hyporheic sediments and benthic biofilms. However, fine particles are also known to remobilize under all flow conditions. This combination of downstream transport and transient retention, influenced by stream geomorphology, controls the distribution of residence times over which fine particles influence stream ecosystems. The main objective of this study was to quantify immobilization and remobilization rates of fine particles in a third-order sand-and-gravel bed stream (Difficult Run, Virginia, USA) within different geomorphic units of the stream (i.e., pool, lateral cavity, and thalweg). During our field injection experiment, a thunderstorm-driven spate allowed us to observe fine particle dynamics during both base flow and in response to increased flow. Solute and fine particles were measured within stream surface waters, pore waters, sediment cores, and biofilms on cobbles. Measurements were taken at four different subsurface locations with varying geomorphology and at multiple depths. Approximately 68% of injected fine particles were retained during base flow until the onset of the spate. Retention was evident even after the spate, with 15.4% of the fine particles deposited during base flow still retained within benthic biofilms on cobbles and 14.9% within hyporheic sediment after the spate. Thus, through the combination of short-term remobilization and long-term retention, fine particles can serve as sources of carbon and nutrients to downstream ecosystems over a range of time scales.

The sedimentation of fine particles in liquid foams

OpenAIRE

Rouyer , Florence; Fritz , Christelle; Pitois , Olivier

2010-01-01

International audience; We investigate the sedimentation of fine particles in liquid channels of foams. The study combines numerical simulations with experiments performed in foams and in isolated vertical foam channels. Results show that particulate motion is controlled by the confinement parameter (l) and the mobility of the channel surfaces modelled by interfacial shear viscosity. Interestingly, whereas the position of the particle within the channel cross-section is expected to be a relev...

Air quality at outdoor community events: findings from fine particulate (PM2.5) sampling at festivals in Edmonton, Alberta.

Science.gov (United States)

Collins, Damian; Parsons, Marc; Zinyemba, Chaka

2014-01-01

Exposure to fine particulate matter (PM2.5) is associated with a broad range of health risks. This study assessed the impacts of cooking smoke and environmental tobacco smoke on air quality at outdoor community events in Edmonton, Alberta (Canada). Data were collected at three festivals in July-August 2011 using a portable real-time airborne particle monitor. The pooled mean PM2.5 level was 12.41 μg/m(3). Peak readings varied from 52 to 1877 μg/m(3). Mean PM2.5 near food stalls was 35.42 μg/m(3), which exceeds the WHO limit for 24 h exposure. Mean PM2.5 levels with smokers present were 16.39 μg/m(3) (all points) and 9.64 μg/m(3) (excluding points near food stalls). Although some smokers withdrew from common spaces, on average 20 smokers/hour were observed within 3 m. Extending smoking bans would improve air quality and address related concerns. However, food preparation is a more pressing area for policy action to reduce PM2.5 exposure at these community events.

Sources of mutagenic activity in urban fine particles

International Nuclear Information System (INIS)

Stevens, R.K.; Lewis, C.W.; Dzubay, T.G.; Cupitt, L.T.; Lewtas, J.

1990-01-01

Samples were collected during the winter of 1984-1985 in the cities of Albuquerque, NM and Raleigh NC as part of a US Environmental Protection Agency study to evaluate methods to determine the emission sources contributing to the mutagenic properties of extractable organic matter (EOM) present in fine particles. Data derived from the analysis of the composition of these fine particles served as input to a multi-linear regression (MLR) model used to calculate the relative contribution of wood burning and motor vehicle sources to mutagenic activity observed in the extractable organic matter. At both sites the mutagenic potency of EOM was found to be greater (3-5 times) for mobile sources when compared to wood smoke extractable organics. Carbon-14 measurements which give a direct determination of the amount of EOM that originated from wood burning were in close agreement with the source apportionment results derived from the MLR model

Experimental investigation on improving the removal effect of WFGD system on fine particles by heterogeneous condensation

Energy Technology Data Exchange (ETDEWEB)

Bao, Jingjing; Yang, Linjun; Yan, Jinpei; Xiong, Guilong; Shen, Xianglin [Southeast Univ., Nanjing (China). School of Energy and Environment

2013-07-01

Heterogeneous condensation of water vapor as a preconditioning technique for the removal of fine particles from flue gas was investigated experimentally in a wet flue gas desulfurization (WFGD) system. A supersaturated vapor phase, necessary for condensational growth of fine particles, was achieved in the SO{sub 2} absorption zone and at the top of the wet FGD scrubber by adding steam in the gas inlet and above the scrubbing liquid inlet of the scrubber, respectively. The condensational grown droplets were then removed by the scrubbing liquid and a high-efficiency demister. The results show that the effectiveness of the WFGD system for removal of fine particles is related to the SO{sub 2} absorbent and the types of scrubber employed. Despite a little better effectiveness for the removal of fine particles in the rotating-stream-tray scrubber at the same liquid-to-gas ratio, The similar trends are obtained between the spray scrubber and rotating-stream-tray scrubber. Due to the formation of aerosol particles in the limestone and ammonia-based FGD processes, the fine particle removal efficiencies are lower than those for Na{sub 2}CO{sub 3} and water. The performance of the WFGD system for removal of fine particles can be significantly improved for both steam addition cases, for which the removal efficiency increases with increasing amount of added steam. A high liquid to gas ratio is beneficial for efficient removal of fine particles by heterogeneous condensation of water vapor.

Indoor particle levels in small- and medium-sized commercial buildings in California.

Science.gov (United States)

Wu, Xiangmei May; Apte, Michael G; Bennett, Deborah H

2012-11-20

This study monitored indoor and outdoor particle concentrations in 37 small and medium commercial buildings (SMCBs) in California with three buildings sampled on two occasions, resulting in 40 sampling days. Sampled buildings included offices, retail establishments, restaurants, dental offices, and hair salons, among others. Continuous measurements were made for both ultrafine and fine particulate matter as well as black carbon inside and outside of the building. Integrated PM(2.5), PM(2.5-10), and PM(10) samples were also collected inside and outside the building. The majority of the buildings had indoor/outdoor (I/O) particle concentration ratios less than 1.0, indicating that contributions from indoor sources are less than removal of outdoor particles. However, some of the buildings had I/O ratios greater than 1, indicating significant indoor particle sources. This was particularly true of restaurants, hair salons, and dental offices. The infiltration factor was estimated from a regression analysis of indoor and outdoor concentrations for each particle size fraction, finding lower values for ultrafine and coarse particles than for submicrometer particles, as expected. The I/O ratio of black carbon was used as a relative measure of the infiltration factor of particles among buildings, with a geometric mean of 0.62. The contribution of indoor sources to indoor particle levels was estimated for each building.

Retention and Migration of Fine Organic Particles within an Agricultural Stream: Toenepi, Waikato, New Zealand

Science.gov (United States)

Drummond, J. D.; Davies-Colley, R.; Stott, R.; Sukias, J.; Nagels, J.; Sharp, A.; Packman, A. I.

2013-12-01

Fine organic particle dynamics are important to stream biogeochemistry, ecology, and transport of contaminant microbes. These particles migrate downstream through a series of deposition and resuspension events, which results in a wide range of residence times. This retention influences biogeochemical processing and in-stream stores of contaminant microbes that may mobilize during flood events and present a hazard to downstream uses such as water supplies and recreation. We are conducting studies to gain insights into organic particle dynamics in streams, with a campaign of experiments and modeling. The results should improve understanding of nutrient (C, N, P) spiraling and fine sediment movement in streams, and have particular application to microbial hazards. We directly measure microbial transport by including the indicator organism, E. coli, as a tracer, which is compared to a fluorescent inert particle tracer and conservative solute to gain insight on both microbial ecology and waterborne disease transmission. We developed a stochastic model to describe the transport and retention of fine suspended particles in rivers, including advective delivery of particles to the streambed, transport through porewaters, and reversible filtration within the streambed. Because fine particles are only episodically transported in streams, with intervening periods at rest in the bed, this transport process violates conventional advection-dispersion assumptions. Instead we adopt a stochastic mobile-immobile model formulation to describe fine particle transport. We apply this model to measurements of particle transport from multiple tracer experiments in an agricultural stream in the Waikato dairy region of New Zealand, and use the model to improve interpretation of baseflow particle dynamics. Our results show the importance of the benthic and hyporheic regions and in-stream vegetation as a reservoir for fine organic particles in streams.

Iron solubility related to particle sulfur content in source emission and ambient fine particles.

Science.gov (United States)

Oakes, M; Ingall, E D; Lai, B; Shafer, M M; Hays, M D; Liu, Z G; Russell, A G; Weber, R J

2012-06-19

The chemical factors influencing iron solubility (soluble iron/total iron) were investigated in source emission (e.g., biomass burning, coal fly ash, mineral dust, and mobile exhaust) and ambient (Atlanta, GA) fine particles (PM2.5). Chemical properties (speciation and mixing state) of iron-containing particles were characterized using X-ray absorption near edge structure (XANES) spectroscopy and micro-X-ray fluorescence measurements. Bulk iron solubility (soluble iron/total iron) of the samples was quantified by leaching experiments. Major differences were observed in iron solubility in source emission samples, ranging from low solubility (iron solubility did not correspond to silicon content or Fe(II) content. However, source emission and ambient samples with high iron solubility corresponded to the sulfur content observed in single particles. A similar correspondence between bulk iron solubility and bulk sulfate content in a series of Atlanta PM2.5 fine particle samples (N = 358) further supported this trend. In addition, results of linear combination fitting experiments show the presence of iron sulfates in several high iron solubility source emission and ambient PM2.5 samples. These results suggest that the sulfate content (related to the presence of iron sulfates and/or acid-processing mechanisms by H(2)SO(4)) of iron-containing particles is an important proxy for iron solubility.

Characterization of Spatial Impact of Particles Emitted from a Cement Material Production Facility on Outdoor Particle Deposition in the Surrounding Community.

Science.gov (United States)

Yu, Chang Ho; Fan, Zhihua Tina; McCandlish, Elizabeth; Stern, Alan H; Lioy, Paul J

2011-10-01

The objective of this study was to estimate the contribution of a facility that processes steel production slag into raw material for cement production to local outdoor particle deposition in Camden, NJ. A dry deposition sampler that can house four 37-mm quartz fiber filters was developed and used for the collection of atmospheric particle deposits. Two rounds of particle collection (3-4 weeks each) were conducted in 8-11 locations 200-800 m downwind of the facility. Background samples were concurrently collected in a remote area located ∼2 km upwind from the facility. In addition, duplicate surface wipe samples were collected side-by-side from each of the 13 locations within the same sampling area during the first deposition sampling period. One composite source material sample was also collected from a pile stored in the facility. Both the bulk of the source material and the particle deposition flux in the study area was higher (24-83 mg/m 2 ·day) than at the background sites (13-17 mg/m 2 ·day). The concentration of Ca, a major element in the cement source production material, was found to exponentially decrease with increasing downwind distance from the facility (P particle deposition. The contribution of the facility to outdoor deposited particle mass was further estimated by three independent models using the measurements obtained from this study. The estimated contributions to particle deposition in the study area were 1.8-7.4% from the regression analysis of the Ca concentration in particle deposition samples against the distance from the facility, 0-11% from the U.S. Environmental Protection Agency (EPA) Chemical Mass Balance (CMB) source-receptor model, and 7.6-13% from the EPA Industrial Source Complex Short Term (ISCST3) dispersion model using the particle-size-adjusted permit-based emissions estimates. [Box: see text].

Particle Swarm Optimization for Outdoor Lighting Design

Directory of Open Access Journals (Sweden)

Ana Castillo-Martinez

2017-01-01

Full Text Available Outdoor lighting is an essential service for modern life. However, the high influence of this type of facility on energy consumption makes it necessary to take extra care in the design phase. Therefore, this manuscript describes an algorithm to help light designers to get, in an easy way, the best configuration parameters and to improve energy efficiency, while ensuring a minimum level of overall uniformity. To make this possible, we used a particle swarm optimization (PSO algorithm. These algorithms are well established, and are simple and effective to solve optimization problems. To take into account the most influential parameters on lighting and energy efficiency, 500 simulations were performed using DIALux software (4.10.0.2, DIAL, Ludenscheid, Germany. Next, the relation between these parameters was studied using to data mining software. Subsequently, we conducted two experiments for setting parameters that enabled the best configuration algorithm in order to improve efficiency in the proposed process optimization.

Restraint of fatigue crack growth by wedge effects of fine particles

CERN Document Server

Takahashi, I; Kotani, N

2000-01-01

Presents some experimental results which demonstrate restraint of fatigue crack growth in an Al-Mg alloy by wedge effects of fine particles. Fatigue test specimens were machined from a JIS A5083P-O Al-Mg alloy plate of 5 mm thickness and an EDM starter notch was introduced to each specimen. Three kinds of fine particles were prepared as the materials to be wedged into the fatigue cracks, i.e. magnetic particles and two kinds of alumina particles having different mean particle sizes of 47.3 mu m and 15.2 mu m. Particles of each kind were suspended in an oil to form a paste, which was applied on the specimen surface covering the notch zone prior to the fatigue tests. In order to make some fracture mechanics approaches, in situ observations of fatigue cracks were performed for the two cases using a CCD microscope, with a magnification of *1000. The crack length and the crack opening displacement (COD) at the notch root, delta , were measured. The crack retardation effect continues almost through the entire lifet...

A Constitutive Relationship for Gravelly Soil Considering Fine Particle Suffusion.

Science.gov (United States)

Zhang, Yuning; Chen, Yulong

2017-10-23

Suffusion erosion may occur in sandy gravel dam foundations that use suspended cutoff walls. This erosion causes a loss of fine particles, degrades the soil strength and deformation moduli, and adversely impacts the cutoff walls of the dam foundation, as well as the overlying dam body. A comprehensive evaluation of these effects requires models that quantitatively describe the effects of fine particle losses on the stress-strain relationships of sandy gravels. In this work, we propose an experimental scheme for studying these types of models, and then perform triaxial and confined compression tests to determine the effects of particle losses on the stress-strain relationships. Considering the Duncan-Chang E-B model, quantitative expressions describing the relationship between the parameters of the model and the particle losses were derived. The results show that particle losses did not alter the qualitative stress-strain characteristics of the soils; however, the soil strength and deformation moduli were degraded. By establishing the relationship between the parameters of the model and the losses, the same model can then be used to describe the relationship between sandy gravels and erosion levels that vary in both time and space.

A Constitutive Relationship for Gravelly Soil Considering Fine Particle Suffusion

Directory of Open Access Journals (Sweden)

Yuning Zhang

2017-10-01

Full Text Available Suffusion erosion may occur in sandy gravel dam foundations that use suspended cutoff walls. This erosion causes a loss of fine particles, degrades the soil strength and deformation moduli, and adversely impacts the cutoff walls of the dam foundation, as well as the overlying dam body. A comprehensive evaluation of these effects requires models that quantitatively describe the effects of fine particle losses on the stress-strain relationships of sandy gravels. In this work, we propose an experimental scheme for studying these types of models, and then perform triaxial and confined compression tests to determine the effects of particle losses on the stress-strain relationships. Considering the Duncan-Chang E-B model, quantitative expressions describing the relationship between the parameters of the model and the particle losses were derived. The results show that particle losses did not alter the qualitative stress-strain characteristics of the soils; however, the soil strength and deformation moduli were degraded. By establishing the relationship between the parameters of the model and the losses, the same model can then be used to describe the relationship between sandy gravels and erosion levels that vary in both time and space.

A Modelling Approach on Fine Particle Spatial Distribution for Street Canyons in Asian Residential Community

Science.gov (United States)

Ling, Hong; Lung, Shih-Chun Candice; Uhrner, Ulrich

2016-04-01

Rapidly increasing urban pollution poses severe health risks.Especially fine particles pollution is considered to be closely related to respiratory and cardiovascular disease. In this work, ambient fine particles are studied in street canyons of a typical Asian residential community using a computational fluid dynamics (CFD) dispersion modelling approach. The community is characterised by an artery road with a busy traffic flow of about 4000 light vehicles (mainly cars and motorcycles) per hour at rush hours, three streets with hundreds light vehicles per hour at rush hours and several small lanes with less traffic. The objective is to study the spatial distribution of the ambient fine particle concentrations within micro-environments, in order to assess fine particle exposure of the people living in the community. The GRAL modelling system is used to simulate and assess the emission and dispersion of the traffic-related fine particles within the community. Traffic emission factors and traffic situation is assigned using both field observation and local emissions inventory data. High resolution digital elevation data (DEM) and building height data are used to resolve the topographical features. Air quality monitoring and mobile monitoring within the community is used to validate the simulation results. By using this modelling approach, the dispersion of fine particles in street canyons is simulated; the impact of wind condition and street orientation are investigated; the contributions of car and motorcycle emissions are quantified respectively; the residents' exposure level of fine particles is assessed. The study is funded by "Taiwan Megacity Environmental Research (II)-chemistry and environmental impacts of boundary layer aerosols (Year 2-3) (103-2111-M-001-001-); Spatial variability and organic markers of aerosols (Year 3)(104-2111-M-001 -005 -)"

Theoretical Studies of Strongly Interacting Fine Particle Systems

Science.gov (United States)

Fearon, Michael

Available from UMI in association with The British Library. A theoretical analysis of the time dependent behaviour of a system of fine magnetic particles as a function of applied field and temperature was carried out. The model used was based on a theory assuming Neel relaxation with a distribution of particle sizes. This theory predicted a linear variation of S_{max} with temperature and a finite intercept, which is not reflected by experimental observations. The remanence curves of strongly interacting fine-particle systems were also investigated theoretically. It was shown that the Henkel plot of the dc demagnetisation remanence vs the isothermal remanence is a useful representation of interactions. The form of the plot was found to be a reflection of the magnetic and physical microstructure of the material, which is consistent with experimental data. The relationship between the Henkel plot and the noise of a particulate recording medium, another property dependent on the microstructure, is also considered. The Interaction Field Factor (IFF), a single parameter characterising the non-linearity of the Henkel plot, is investigated. These results are consistent with a previous experimental study. Finally the results of the noise power spectral density for erased and saturated recording media are presented, so that characterisation of interparticle interactions may be carried out with greater accuracy.

CDC WONDER: Daily Fine Particulate Matter

Data.gov (United States)

U.S. Department of Health & Human Services — The Daily Fine Particulate Matter data available on CDC WONDER are geographically aggregated daily measures of fine particulate matter in the outdoor air, spanning...

Microbial and Organic Fine Particle Transport Dynamics in Streams - a Combined Experimental and Stochastic Modeling Approach

Science.gov (United States)

Drummond, Jen; Davies-Colley, Rob; Stott, Rebecca; Sukias, James; Nagels, John; Sharp, Alice; Packman, Aaron

2014-05-01

Transport dynamics of microbial cells and organic fine particles are important to stream ecology and biogeochemistry. Cells and particles continuously deposit and resuspend during downstream transport owing to a variety of processes including gravitational settling, interactions with in-stream structures or biofilms at the sediment-water interface, and hyporheic exchange and filtration within underlying sediments. Deposited cells and particles are also resuspended following increases in streamflow. Fine particle retention influences biogeochemical processing of substrates and nutrients (C, N, P), while remobilization of pathogenic microbes during flood events presents a hazard to downstream uses such as water supplies and recreation. We are conducting studies to gain insights into the dynamics of fine particles and microbes in streams, with a campaign of experiments and modeling. The results improve understanding of fine sediment transport, carbon cycling, nutrient spiraling, and microbial hazards in streams. We developed a stochastic model to describe the transport and retention of fine particles and microbes in rivers that accounts for hyporheic exchange and transport through porewaters, reversible filtration within the streambed, and microbial inactivation in the water column and subsurface. This model framework is an advance over previous work in that it incorporates detailed transport and retention processes that are amenable to measurement. Solute, particle, and microbial transport were observed both locally within sediment and at the whole-stream scale. A multi-tracer whole-stream injection experiment compared the transport and retention of a conservative solute, fluorescent fine particles, and the fecal indicator bacterium Escherichia coli. Retention occurred within both the underlying sediment bed and stands of submerged macrophytes. The results demonstrate that the combination of local measurements, whole-stream tracer experiments, and advanced modeling

Deposition velocities to Sorbus aria, Acer campestre, Populus deltoides x trichocarpa 'Beaupre', Pinus nigra and x Cupressocyparis leylandii for coarse, fine and ultra-fine particles in the urban environment

International Nuclear Information System (INIS)

Freer-Smith, P.H.; Beckett, K.P.; Taylor, Gail

2005-01-01

Trees are effective in the capture of particles from urban air to the extent that they can significantly improve urban air quality. As a result of their aerodynamic properties conifers, with their smaller leaves and more complex shoot structures, have been shown to capture larger amounts of particle matter than broadleaved trees. This study focuses on the effects of particle size on the deposition velocity of particles (Vg) to five urban tree species (coniferous and broadleaved) measured at two field sites, one urban and polluted and a second more rural. The larger uptake to conifers is confirmed, and for broadleaves and conifers Vg values are shown to be greater for ultra-fine particles (Dp<1.0 μm) than for fine and coarse particles. This is important since finer particles are more likely to be deposited deep in the alveoli of the human lung causing adverse health effects. The finer particle fraction is also shown to be transported further from the emission source; in this study a busy urban road. In further sets of data the aqueous soluble and insoluble fractions of the ultra-fines were separated, indicating that aqueous insoluble particles made up only a small proportion of the ultra-fines. Much of the ultra-fine fraction is present as aerosol. Chemical analysis of the aqueous soluble fractions of coarse, fine and ultra-fine particles showed the importance of nitrates, chloride and phosphates in all three size categories at the polluted and more rural location

Preparation of UO_2 Fine Particle by Hydrolysis of Uranium(IV) Alkoxide

OpenAIRE

Satoh, Isamu; Takahashi, Mitsuyuki; Miura, Shigeyuki

1997-01-01

Fine particles of uranium(IV) dioxides were obtained by hydrolysis of uranium(IV) ethoxide which was synthesized by reacting uranium tetrachloride with sodium ethoxide. The monodispersed submicrometer particles were confirmed by SEM observation.

Particle size distribution and property of bacteria attached to carbon fines in drinking water treatment

Directory of Open Access Journals (Sweden)

Wang Leilei

2008-06-01

Full Text Available The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon (GAC filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 µm in size. The concentration in the GAC effluent (561 particles/mL was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 µm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 µm and 15 µm increasing. The most probable number (MPN of carbon fines reached 43 unit/L after six hours and fines between 0.45 µm and 8.0 µm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU (colony-forming units/mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine (90% was higher than that with chlorine (70%. Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.

Study of nitro-polycyclic aromatic hydrocarbons in fine and coarse atmospheric particles

Science.gov (United States)

Teixeira, Elba Calesso; Garcia, Karine Oliveira; Meincke, Larissa; Leal, Karen Alam

2011-08-01

The purpose of the present study was to evaluate six nitro-polycyclic aromatic hydrocarbons (NPAHs) in fine (MAPA), RS, Brazil. The method used was of NPAHs isolation and derivatization, and subsequent gas chromatography by electron capture detection (CG/ECD). Results revealed a higher concentration of NPAHs, especially 3-nitrofluoranthene and 1-nitropyrene, in fine particles in the sampling sites studied within the MAPA. The diagnostic ratios calculated for PAHs and NPAHs identified the influence of heavy traffic, mainly of diesel emissions. The correlation of NPAHs with other pollutants (NO x, NO 2, NO and O 3) evidence the influence of vehicular emissions in the MAPA. The seasonal variation evidenced higher NPAHs concentrations in the fine particles during winter for most compounds studied.

Monitoring of airborne biological particles in outdoor atmosphere. Part 1: Importance, variability and ratios.

Science.gov (United States)

Núñez, Andrés; Amo de Paz, Guillermo; Rastrojo, Alberto; García, Ana M; Alcamí, Antonio; Gutiérrez-Bustillo, A Montserrat; Moreno, Diego A

2016-03-01

The first part of this review ("Monitoring of airborne biological particles in outdoor atmosphere. Part 1: Importance, variability and ratios") describes the current knowledge on the major biological particles present in the air regarding their global distribution, concentrations, ratios and influence of meteorological factors in an attempt to provide a framework for monitoring their biodiversity and variability in such a singular environment as the atmosphere. Viruses, bacteria, fungi, pollen and fragments thereof are the most abundant microscopic biological particles in the air outdoors. Some of them can cause allergy and severe diseases in humans, other animals and plants, with the subsequent economic impact. Despite the harsh conditions, they can be found from land and sea surfaces to beyond the troposphere and have been proposed to play a role also in weather conditions and climate change by acting as nucleation particles and inducing water vapour condensation. In regards to their global distribution, marine environments act mostly as a source for bacteria while continents additionally provide fungal and pollen elements. Within terrestrial environments, their abundances and diversity seem to be influenced by the land-use type (rural, urban, coastal) and their particularities. Temporal variability has been observed for all these organisms, mostly triggered by global changes in temperature, relative humidity, et cetera. Local fluctuations in meteorological factors may also result in pronounced changes in the airbiota. Although biological particles can be transported several hundreds of meters from the original source, and even intercontinentally, the time and final distance travelled are strongly influenced by factors such as wind speed and direction. [Int Microbiol 2016; 19(1):1-1 3]. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

Urban cyclist exposure to fine particle pollution in a rapidly growing city

Science.gov (United States)

Luce, B. W.; Barrett, T. E.; Ponette-González, A.

2017-12-01

Urban cyclists are exposed to elevated atmospheric concentrations of fine particulate matter (particles vehicle exhaust, which is emitted directly into cyclists' "breathing zone." In cities, human exposure to PM2.5 is a concern because its small size allows it to be inhaled deeper into the lungs than most particles. The aim of this research is to determine "hotspots" (locations with high PM2.5 concentrations) within the Dallas-Fort Worth Metroplex, Texas, where urban cyclists are most exposed to fine particle pollution. Recent research indicates that common exposure hotspots include traffic signals, junctions, bus stations, parking lots, and inclined streets. To identify these and other hotspots, a bicycle equipped with a low-cost, portable, battery-powered particle counter (Dylos 1700) coupled with a Trimble Geo 5T handheld Global Positioning System (GPS; ≤1 m ± resolution) will be used to map and measure particle mass concentrations along predetermined routes. Measurements will be conducted during a consecutive four-month period (Sep-Dec) during morning and evening rush hours when PM2.5 levels are generally highest, as well as during non-rush hour times to determine background concentrations. PM2.5 concentrations will be calculated from particle counts using an equation developed by Steinle et al. (2015). In addition, traffic counts will be conducted along the routes coinciding with the mobile monitoring times. We will present results on identified "hotspots" of high fine particle concentrations and PM2.5 exposure in the City of Denton, where particle pollution puts urban commuters most at risk, as well as average traffic counts from monitoring times. These data can be used to determine pollution mitigation strategies in rapidly growing urban areas.

Size distribution of chemical elements and their source apportionment in ambient coarse, fine, and ultrafine particles in Shanghai urban summer atmosphere.

Science.gov (United States)

Lü, Senlin; Zhang, Rui; Yao, Zhenkun; Yi, Fei; Ren, Jingjing; Wu, Minghong; Feng, Man; Wang, Qingyue

2012-01-01

Ambient coarse particles (diameter 1.8-10 microm), fine particles (diameter 0.1-1.8 microm), and ultrafine particles (diameter Source apportionment of the chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 +/- 2.18, 8.82 +/- 3.52, and 2.02 +/- 0.41 microg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.

Rotating drum tests of particle suspensions within a fines dispersion

Science.gov (United States)

Cabrera, Miguel Angel; Gollin, Devis; Kaitna, Roland; Wu, Wei

2014-05-01

Natural flows like mudflows, debris flow, and hyperconcentrated flows are commonly composed by a matrix of particles suspended in a viscous fluid. The nature of the interactions between particles immersed in a fluid is related to its size. While coarse particles (sand, gravel, and boulders) interact with each other or with the surrounding fluid, a dispersion of fine particles interacts with each other through colloidal forces or Brownian motion effects (Coussot and Piau, 1995, and Ancey and Jorrot, 2001). The predominance of one of the previous interactions defines the rheology of the flow. On this sense, experimental insight is required to validate the limits where the rheology of a dispersion of fines is valid. For this purpose, an experimental program in a rotating drum is performed over samples of sand, loess, and kaolin. The solid concentration and angular velocity of the rotating drum are varied. Height and normal loads are measured during flow. High-speed videos are performed to obtain the flow patterns of the mixtures. The experiments provide new laboratory evidence of granular mixture behaviour within an increased viscous fluid phase and its characterization. The results show an apparent threshold in terms of solid concentration, in which the mixtures started to behave as a shear-dependent material.

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

Energy Technology Data Exchange (ETDEWEB)

Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Delp, William W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Black, Douglas R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-12-01

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250m 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 produced indoor PM_2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection whereas supply MERV16 filtration reduced PM_2.55 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filters in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM_2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM_2.5. 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 PM_2.5 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.

The impact of mass transfer limitations on size distributions of particle associated SVOCs in outdoor and indoor environments

Energy Technology Data Exchange (ETDEWEB)

Liu, Cong; Zhang, Yinping [Department of Building Science, Tsinghua University, Beijing (China); Weschler, Charles J., E-mail: weschlch@rwjms.rutgers.edu [Department of Building Science, Tsinghua University, Beijing (China); Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ (United States); International Center for Indoor Environment and Energy, Technical University of Denmark, Lyngby (Denmark)

2014-11-01

Semi-volatile organic compounds (SVOCs) partition between the gas phase and airborne particles. The size distribution of particle-associated SVOCs impacts their fate in outdoor and indoor environments, as well as human exposure to these compounds and subsequent health risks. Allen et al. (1996) previously proposed that the rate of mass transfer can impact polycyclic aromatic hydrocarbon (PAH) partitioning among different sized particles, especially for time scales relevant to urban aerosols. The present study quantitatively builds on this idea, presenting a model that incorporates dynamic SVOC/particle interaction and applying this model to typical outdoor and indoor scenarios. The model indicates that the impact of mass transfer limitations on the size distribution of a particle-associated SVOC can be evaluated by the ratio of the time to achieve gas–particle equilibrium relative to the residence time of particles. The higher this ratio, the greater the influence of mass transfer limitations on the size distribution of particle-associated SVOCs. The influence of such constraints is largest on the fraction of particle-associated SVOCs in the coarse mode (> 2 μm). Predictions from the model have been found to be in reasonable agreement with size distributions measured for PAHs at roadside and suburban locations in Japan. The model also quantitatively explains shifts in the size distributions of particle associated SVOCs compared to those for particle mass, and the manner in which these shifts vary with temperature and an SVOC's molecular weight. - Highlights: • Rate of mass transfer can impact SVOC partitioning among different sized particles. • Model was developed that incorporates dynamic SVOC/particle sorption. • Key parameters: mass-transfer coefficients, partition coefficient, residence time • Model explains observed SVOC size distribution shifts with temperature and MW. • Largest impact of mass transfer constraints: SVOC sorption to coarse

Mercury speciation and fine particle size distribution on combustion of Chinese coals

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lei; Wang, Shuxiao; Hao, Jiming [Tsinghua Univ., Beijing (China). Dept. of Environmental Science and Engineering and State Key Joint Lab. of Environment Simulation and Pollution Control; Daukoru, Michael; Torkamani, Sarah; Biswas, Pratim [Washington Univ., St. Louis, MO (United States). Aerosol and Air Quality Research Lab.

2013-07-01

Coal combustion is the dominant anthropogenic mercury emission source of the world. Electrostatic precipitator (ESP) can remove almost all the particulate mercury (Hg{sub p}), and wet flue gas desulfurization (WFGD) can retain a large part of the gaseous oxidized mercury (Hg{sup 2+}). Only a small percentage of gaseous elemental mercury (Hg{sup 0}) can be abated by the air pollution control devices (APCDs). Therefore, the mercury behavior across APCDs largely depends on the mercury speciation in the flue gas exhausting from the coal combustor. To better understand the formation process of three mercury species, i.e. Hg{sup 0}, Hg{sup 2+} and Hg{sub p}, in gaseous phase and fine particles, bench-scale measurements for the flue gas exhausting from combustion of different types of coal in a drop-tube furnace set-up, were carried out. It was observed that with the limitation of reaction kinetics, higher mercury concentration in flue gas will lead to lower Hg{sup 2+} proportion. The concentration of chlorine has the opposite effect, not as significantly as that of mercury though. With the chlorine concentration increasing, the proportion of Hg{sup 2+} increases. Combusting the finer coal powder results in the formation of more Hg{sup 2+}. Mineral composition of coal and coal particle size has a great impact on fine particle formation. Al in coal is in favor of finer particle formation, while Fe in coal can benefit the formation of larger particles. The coexistence of Al and Si can strengthen the particle coagulation process. This process can also be improved by the feeding of more or finer coal powder. The oxy-coal condition can make for both the mercury oxidation process and the metal oxidation in the fine particle formation process.

A New Type of Non-Mechanical Valves for Recirculation of Fine Particles

DEFF Research Database (Denmark)

Azizaddini, Seyednezamaddin

of the thesis is to design a new version of a non-mechanical valve for transportation of the particles and closing the loop in circulating or interconnected fluidized bed systems. As the primary proposal, combination of three assistive methods (tapered fluidized bed, mixture of coarse and fine particles...

Estimating mortality derived from indoor exposure to particles of outdoor origin.

Directory of Open Access Journals (Sweden)

Wenjing Ji

Full Text Available Following an extensive review of the literature, we further analyze the published data to examine the health effects of indoor exposure to particulate matter (PM of outdoor origin. We obtained data on all-cause, cardiovascular, and respiratory mortality per 10 μg/m3 increase in outdoor PM10 or PM2.5; the infiltration factors for buildings; and estimated time spent outdoors by individuals in the United States, Europe, China, and globally. These data were combined log-linear exposure-response model to estimate the all-cause, cardiovascular, and respiratory mortality of exposure to indoor PM pollution of outdoor origin. Indoor PM pollution of outdoor origin is a cause of considerable mortality, accounting for 81% to 89% of the total increase in mortality associated with exposure to outdoor PM pollution for the studied regions. The findings suggest that enhancing the capacity of buildings to protect occupants against exposure to outdoor PM pollution has significant potential to improve public health outcomes.

ESF collection effectiveness, a study in fine particle dynamics

International Nuclear Information System (INIS)

Winegardner, W.K.; Owczarski, P.C.

1985-04-01

The characterization and dynamic behavior of fine particles are the main subjects of an ongoing investigation of the particle collection effectiveness of the engineered safety feature (ESF) systems in nuclear power plants. This investigation is part of a larger study of the release of radionuclides to the environment from such plants during postulated accidents that are severe but extremely unlikely. The ESF systems are installed to prevent the occurrence of severe accidents or mitigate their consequences. Several of these engineered systems can serve as particle collection devices. This report focuses on the analytical models that were developed to predict particle behavior in two systems that were not specifically designed for particle retention: the ice compartments of ice condenser containment systems in Pressurized Water Reactors (PWRs) and the suppression pools of Boiling Water Reactors (BWRs). The following section summarizes the topics considered in the development of models and computer codes for estimating the particle retention effectiveness of these two ESF systems. After the summary this paper describes the two ESF systems in more detail and discusses the behavior of particles in both situations

A novel permanently magnetised high gradient magnetic filter using assisted capture for fine particles

Energy Technology Data Exchange (ETDEWEB)

Watson, J.H.P. [Univ. of Southampton (United Kingdom)

1995-02-01

This paper describes the structure and properties of a novel permanently magnetised magnetic filter for fine friable radioactive material. Previously a filter was described and tested. This filter was designed so that the holes in the filter are left open as capture proceeds which means the pressure drop builds up only slowly. This filter is not suitable for friable composite particles which can be broken by mechanical forces. The structure of magnetic part of the second filter has been changed so as to strongly capture particles composed of fine particles weakly bound together which tend to break when captured. This uses a principle of assisted-capture in which coarse particles aid the capture of the fine fragments. The technique has the unfortunate consequence that the pressure drop across the filter rises faster as capture capture proceeds than the filter described previously. These filters have the following characteristics: (1) No external magnet is required. (2) No external power is required. (3) Small is size and portable. (4) Easily interchangeable. (5) Can be cleaned without demagnetising.

Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations

Science.gov (United States)

Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

1996-08-01

An atmospheric transport model has been used to explore the relationship between source emissions and ambient air quality for individual particle phase organic compounds present in primary aerosol source emissions. An inventory of fine particulate organic compound emissions was assembled for the Los Angeles area in the year 1982. Sources characterized included noncatalyst- and catalyst-equipped autos, diesel trucks, paved road dust, tire wear, brake lining dust, meat cooking operations, industrial oil-fired boilers, roofing tar pots, natural gas combustion in residential homes, cigarette smoke, fireplaces burning oak and pine wood, and plant leaf abrasion products. These primary fine particle source emissions were supplied to a computer-based model that simulates atmospheric transport, dispersion, and dry deposition based on the time series of hourly wind observations and mixing depths. Monthly average fine particle organic compound concentrations that would prevail if the primary organic aerosol were transported without chemical reaction were computed for more than 100 organic compounds within an 80 km × 80 km modeling area centered over Los Angeles. The monthly average compound concentrations predicted by the transport model were compared to atmospheric measurements made at monitoring sites within the study area during 1982. The predicted seasonal variation and absolute values of the concentrations of the more stable compounds are found to be in reasonable agreement with the ambient observations. While model predictions for the higher molecular weight polycyclic aromatic hydrocarbons (PAH) are in agreement with ambient observations, lower molecular weight PAH show much higher predicted than measured atmospheric concentrations in the particle phase, indicating atmospheric decay by chemical reactions or evaporation from the particle phase. The atmospheric concentrations of dicarboxylic acids and aromatic polycarboxylic acids greatly exceed the contributions that

Fine particles flotation of the Moatize coal/Mozambique

Science.gov (United States)

Castro, Amilton; de Brum, Irineu A. S.

2017-11-01

This study was done from a sample of coal mined at the Vale-Mozambique mine, located in Moatize district, Tete Province. The aim of this work is to analyze the reagent system in the flotation of coal fines belonging to the UCB layer. Among coal processing methods, flotation stands out as one of the most important for the concentration of this material, in particular in the treatment of fine particles. The total feed of the Vale-Mozambique processing plant is 8000 tph of coal, where 10% of this feed corresponds to the fine fraction that feeds the flotation circuit. The material used in this study had a particle size of 96% smaller than 0.25 mm. The reagents used in the flotation tests were Betacol and diesel oil as hydrophobizing agents and MIBC as frother. The range of Betacol concentrations in the first test phase was 200 g / t at 500 g / t, and in the second phase 200 g / t at 500 g / t of diesel oil and MIBC were kept constant at 300 g / t. The immediate analysis followed the Brazilian standards: NBR 8289, NBR 8293, NBR 8290, NBR 8299. The results showed that it is possible, from a feed with the ash content around 22.84%, to obtain products with levels below of 10% ash, with a mass recovery around 50%. The recovery of carbonaceous matter was also evaluated and presented positive results. Complementing this study, the effect of H2O recovery was evaluated and it was observed that for the concentrations of Betacol the recoveries ranged from 6 to 9%, and for diesel oil plus MIBC were 4 to 7%.

Probing fine magnetic particles with neutron scattering

International Nuclear Information System (INIS)

Pynn, R.

1991-01-01

Because thermal neutrons are scattered both by nuclei and by unpaired electrons, they provide an ideal probe for studying the atomic and magnetic structures of fine-grained magnetic materials, including nanocrystalline solids, thin epitaxial layers, and colloidal suspensions of magnetic particles, known as ferrofluids. Diffraction, surface reflection, and small angle neutron scattering (SANS) are the techniques used. With the exception of surface reflection, these methods are described in this article. The combination of SANS with refractive-index matching and neutron polarisation analysis is particularly powerful because it allows the magnetic and atomic structures to be determined independently. This technique has been used to study both dilute and concentrated ferrofluid suspensions of relatively monodisperse cobalt particles, subjected to a series of applied magnetic fields. The size of the cobalt particle core and the surrounding surfactant layer were determined. The measured interparticle structure factor agrees well with a recent theory that allows correlations in binary mixtures of magnetic particles to be calculated in the case of complete magnetic alignment. When one of the species in such a binary mixture is a nonmagnetic, cyclindrical macromolecule, application of a magnetic field leads to some degree of alignment of the nonmagnetic species. This result has been demonstrated with tobacco mosaic virus suspended in a water-based ferrofluid

Fine-particle sodium tracer for long-range transport of the Kuwaiti oil-fire smoke

Energy Technology Data Exchange (ETDEWEB)

Lowenthal, D.H.; Borys, R.D.; Rogers, C.F.; Chow, J.C.; Stevens, R.K.

1993-04-23

Evidence for long-range transport of the Kuwaiti oil-fire smoke during the months following the Persian Gulf War has been more or less indirect. However, more-recent data on the aerosol chemistry of Kuwaiti oil-fire plumes provides a direct link between those fires and aerosols collected at the Mauna Loa Observatory (MLO) during the late spring and summer of 1991. By itself, temporal covariation of fine-particle concentrations of elemental carbon, sulfur, and the noncrustal V/Zn ratio in MLO aerosols suggested a link to large-scale oil-combustion sources, but not necessarily to Kuwait. However, high concentrations of fine-particle (0.1-1.0 microm diameter) NaCl were observed in the 'white' oil-fire plumes over Kuwait during the summer of 1991. In the absence of other demonstratable sources of fine-particle Na, these relationships provide a direct link between the Kuwaiti oil-fires and aerosol composition observed at MLO. (Copyright (c) 1993 American Geophysical Union.)

Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques

Institute of Scientific and Technical Information of China (English)

Yumin Zhu; Hua Zhang; Liming Shao; Pinjing He

2015-01-01

Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW).In this study,we investigated fine particles of ＜2 mm,which are small fractions in MSW but constitute a significant component of the total heavy metal content,using bulk detection techniques.A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction.We also discussed the association,speciation and source apportionment of heavy metals.Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of ＜10 μm within the fine particles.Zn-Cu,Pb-Fe and Fe-Mn-Cr had significant correlations in terms of spatial distribution.The overlapped enrichment,spatial association,and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles.The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products.

Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques.

Science.gov (United States)

Zhu, Yumin; Zhang, Hua; Shao, Liming; He, Pinjing

2015-01-01

Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW). In this study, we investigated fine particles of heavy metal content, using bulk detection techniques. A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction. We also discussed the association, speciation and source apportionment of heavy metals. Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles. The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products. Copyright © 2014. Published by Elsevier B.V.

Identifying sources of atmospheric fine particles in Havana City using Positive Matrix Factorization technique

International Nuclear Information System (INIS)

Pinnera, I.; Perez, G.; Ramos, M.; Guibert, R.; Aldape, F.; Flores M, J.; Martinez, M.; Molina, E.; Fernandez, A.

2011-01-01

In previous study a set of samples of fine and coarse airborne particulate matter collected in a urban area of Havana City were analyzed by Particle-Induced X-ray Emission (PIXE) technique. The concentrations of 14 elements (S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br and Pb) were consistently determined in both particle sizes. The analytical database provided by PIXE was statistically analyzed in order to determine the local pollution sources. The Positive Matrix Factorization (PMF) technique was applied to fine particle data in order to identify possible pollution sources. These sources were further verified by enrichment factor (EF) calculation. A general discussion about these results is presented in this work. (Author)

Study of reduction permeability for deposit of fine particles and bacteria in porous media

International Nuclear Information System (INIS)

Restrepo Restrepo, Dora Patricia; Cardona Bernal, Felipe Andres; Usta Diaz, Martha Lucia

2004-01-01

This work shows a theoretical and practical description of the main variables and physical principles that lead to the obstruction by fine particles and therefore a reduction in permeability for unconsolidated porous media with almost a length foot. The results were also adjusted to theoretical model for the obstruction by fine particles in the entrance face. A first study about bacteria plugging was also carried out in order to try to understand it when these bacteria are in the water of injection of a normal process of water flooding

The mechanisms of fine particle generation and electrification during Mount St. Helens volcanic eruption

Science.gov (United States)

Cheng, R. J.

1982-01-01

Microscopical investigation of volcanic ash collected from ground stations during Mount St. Helens eruptions reveal a distinctive bimodel size distribution with high concentrations of particle ranges at (1) 200-100 microns and (2) 20-0.1 microns. Close examination of individual particles shows that most larger ones are solidified magma particles of porous pumice with numerous gas bubbles in the interior and the smaller ones are all glassy fragments without any detectable gas bubbles. Elemental analysis demonstrates that the fine fragments all have a composition similar to that of the larger pumice particles. Laboratory experiments suggest that the formation of the fine fragments is by bursting of glassy bubbles from a partially solidified surface of a crystallizing molten magma particle. The production of gas bubbles is due to the release of absorbed gases in molten magma particles when solubility decreases during phase transition. Diffusion cloud chamber experiments strongly indicate that sub-micron volcanic fragments are highly hygroscopic and extremely active as cloud condensation nuclei. Ice crystals also are evidently formed on those fragments in a supercooled (-20 C) cloud chamber. It has been reported that charge generation from ocean volcanic eruptions is due to contact of molten lava with sea water. This seems to be insufficient to explain the observed rapid and intense lightning activities over Mount St. Helens eruptions. Therefore, a hypothesis is presented here that highly electrically charged fine solid fragments are ejected by bursting of gas bubbles from the surface of a crystallizing molten magma particles.

Elutriation characteristics of fine particles from bubbling fluidized bed incineration for sludge cake treatment.

Science.gov (United States)

Chang, Yu-Min; Chou, Chih-Mei; Su, Kuo-Tung; Hung, Chao-Yang; Wu, Chao-Hsiung

2005-01-01

In this study, measurements of elutriation rate were carried out in a bench scale bubbling fluidized bed incinerator, which was used to combust sludge cake. The particle size distribution and ignition loss were analyzed to study the elutriation characteristics of bubbling fluidized bed incineration. Drawn from the experimental data, the elutriation rate constant K(i)* for fine particles were obtained and correlated with parameters. It was found that most of the solid particles (about 95%) elutriated came from the fluidized medium (inorganic matters), but few came from unburned carbon particles or soot (about 5%). Finally, this paper lists a comparison of K(i)* between this study and the published prediction equations derived or studied in non-incineration modes of fluidized bed. A new and modified correlation is proposed here to estimate the elutriation rate of fine particles emitted from a bubbling fluidized bed incinerator. Primary operation variables (superficial gas velocity and incineration temperature) affecting the elutriation rate are also discussed in the paper.

Design of sustained release fine particles using two-step mechanical powder processing: particle shape modification of drug crystals and dry particle coating with polymer nanoparticle agglomerate.

Science.gov (United States)

Kondo, Keita; Ito, Natsuki; Niwa, Toshiyuki; Danjo, Kazumi

2013-09-10

We attempted to prepare sustained release fine particles using a two-step mechanical powder processing method; particle-shape modification and dry particle coating. First, particle shape of bulk drug was modified by mechanical treatment to yield drug crystals suitable for the coating process. Drug crystals became more rounded with increasing rotation speed, which demonstrates that powerful mechanical stress yields spherical drug crystals with narrow size distribution. This process is the result of destruction, granulation and refinement of drug crystals. Second, the modified drug particles and polymer coating powder were mechanically treated to prepare composite particles. Polymer nanoparticle agglomerate obtained by drying poly(meth)acrylate aqueous dispersion was used as a coating powder. The porous nanoparticle agglomerate has superior coating performance, because it is completely deagglomerated under mechanical stress to form fine fragments that act as guest particles. As a result, spherical drug crystals treated with porous agglomerate were effectively coated by poly(meth)acrylate powder, showing sustained release after curing. From these findings, particle-shape modification of drug crystals and dry particle coating with nanoparticle agglomerate using a mechanical powder processor is expected as an innovative technique for preparing controlled-release coated particles having high drug content and size smaller than 100 μm. Copyright © 2013 Elsevier B.V. All rights reserved.

Measurement of fine breathable particles (PM(2.5)) as a marker of environmental smoke in catering establishments in Zaragoza.

Science.gov (United States)

Nerín, Isabel; Alayeto, Carmen; Córdoba, Rodrigo; López, María José; Nebot, Manel

2011-04-01

To estimate the levels of small breathable suspended particles (PM(2.5)) as atmospheric markers of environmental tobacco smoke in catering establishments in Zaragoza, Spain. An observational study was conducted between October 2006 and April 2008 in various catering establishments in Zaragoza. A SidePack Aerosol Monitor (AM510 model) was used to sample and record the levels of breathable suspended particles (PM(2.5)) indoors and outdoors, and the following variables were collected: smoking policy (smoking allowed, completely banned, or partially banned with non-smoking sections, physically separated or not); percentage of smokers and presence of cigarette ends, ashtrays or smokers in non-smoking sections. A total of 111 venues were sampled. The level of PM(2.5) was eight times higher in smoking venues than in non-smoking ones and also higher than outdoors. The correlation between the level of particles and percentage of smokers was 0.61 (P<.01). In the non-smoking sections without physical separation the level of particles was twice as much as outdoors and similar to physically separated smokers sections. Only a complete ban on smoking in all workplaces, including leisure venues, has been shown to have a positive effect on workers and customers health. The measurement of PM(2.5) can be a simple method to assess the presence of environmental tobacco smoke. Copyright © 2010 SEPAR. Published by Elsevier Espana. All rights reserved.

Ion beam analysis techniques for the elemental fingerprinting of fine particle smoke from vegetation burning in NSW

Energy Technology Data Exchange (ETDEWEB)

Cohen, D. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

Accelerator based ion beam analysis (IBA) techniques, including PIXE, PIGME, RBS and PESA, have been used to analyse elemental compositions of airborne particles covering a 60,000 square kilometres area of Wollongong, Sydney and Newcastle. These IBA techniques provide elemental concentrations for over 20 different elements from hydrogen to lead, they include H, C, N, O, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Ni, Zn, Br and Pb. The four ion beam techniques are performed simultaneously on the 3MV Van de Graaff accelerator at ANSTO and have been described in detail elsewhere. They are sufficiently sensitive to analyse for many of these elements to levels around 10 ng/m{sup 3} or less in about five minutes of accelerator running time per filter. This is more than adequate for aerosol analyses as most filters contain around 150 {mu}g/cm{sup 2} of material which corresponds to about 10{mu}g/m{sup 3} of fine particles in the atmosphere. For this work fine particles are those with diameters less than 2.5{mu}m. Fine particle data has been collected twice a week and analysed for each of the above elements by ANSTO since 1991 at more than 25 different sites throughout NSW. This large dataset set allows us to not only determine the composition of fine particles and to look for signature elements for particular sources but also to use multivariate statistics to define elemental source fingerprints and then to determine the percentage contributions of these fingerprints to the total fine particle mass in the atmosphere. This paper describes the application of these techniques to the study of domestic wood fires and vegetation burning in NSW over a two year period from 1992-93. It also presents, for the first time, fine particle data related to the January 1994 bushfires in NSW. 6 refs., 1 tab., 5 figs.

Ion beam analysis techniques for the elemental fingerprinting of fine particle smoke from vegetation burning in NSW

International Nuclear Information System (INIS)

Cohen, D.

1996-01-01

Accelerator based ion beam analysis (IBA) techniques, including PIXE, PIGME, RBS and PESA, have been used to analyse elemental compositions of airborne particles covering a 60,000 square kilometres area of Wollongong, Sydney and Newcastle. These IBA techniques provide elemental concentrations for over 20 different elements from hydrogen to lead, they include H, C, N, O, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Ni, Zn, Br and Pb. The four ion beam techniques are performed simultaneously on the 3MV Van de Graaff accelerator at ANSTO and have been described in detail elsewhere. They are sufficiently sensitive to analyse for many of these elements to levels around 10 ng/m 3 or less in about five minutes of accelerator running time per filter. This is more than adequate for aerosol analyses as most filters contain around 150 μg/cm 2 of material which corresponds to about 10μg/m 3 of fine particles in the atmosphere. For this work fine particles are those with diameters less than 2.5μm. Fine particle data has been collected twice a week and analysed for each of the above elements by ANSTO since 1991 at more than 25 different sites throughout NSW. This large dataset set allows us to not only determine the composition of fine particles and to look for signature elements for particular sources but also to use multivariate statistics to define elemental source fingerprints and then to determine the percentage contributions of these fingerprints to the total fine particle mass in the atmosphere. This paper describes the application of these techniques to the study of domestic wood fires and vegetation burning in NSW over a two year period from 1992-93. It also presents, for the first time, fine particle data related to the January 1994 bushfires in NSW. 6 refs., 1 tab., 5 figs

Ion beam analysis techniques for the elemental fingerprinting of fine particle smoke from vegetation burning in NSW

Energy Technology Data Exchange (ETDEWEB)

Cohen, D [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

Accelerator based ion beam analysis (IBA) techniques, including PIXE, PIGME, RBS and PESA, have been used to analyse elemental compositions of airborne particles covering a 60,000 square kilometres area of Wollongong, Sydney and Newcastle. These IBA techniques provide elemental concentrations for over 20 different elements from hydrogen to lead, they include H, C, N, O, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Ni, Zn, Br and Pb. The four ion beam techniques are performed simultaneously on the 3MV Van de Graaff accelerator at ANSTO and have been described in detail elsewhere. They are sufficiently sensitive to analyse for many of these elements to levels around 10 ng/m{sup 3} or less in about five minutes of accelerator running time per filter. This is more than adequate for aerosol analyses as most filters contain around 150 {mu}g/cm{sup 2} of material which corresponds to about 10{mu}g/m{sup 3} of fine particles in the atmosphere. For this work fine particles are those with diameters less than 2.5{mu}m. Fine particle data has been collected twice a week and analysed for each of the above elements by ANSTO since 1991 at more than 25 different sites throughout NSW. This large dataset set allows us to not only determine the composition of fine particles and to look for signature elements for particular sources but also to use multivariate statistics to define elemental source fingerprints and then to determine the percentage contributions of these fingerprints to the total fine particle mass in the atmosphere. This paper describes the application of these techniques to the study of domestic wood fires and vegetation burning in NSW over a two year period from 1992-93. It also presents, for the first time, fine particle data related to the January 1994 bushfires in NSW. 6 refs., 1 tab., 5 figs.

Elemental analysis of airborne fine particles collected at the roadside of an arterial road

International Nuclear Information System (INIS)

Hirabayashi, M.

2008-01-01

Airborne particulate matter was collected at the intersection of Industrial Road in Kawasaki-city, Kanagawa, Japan using a 12-stage low-pressure impactor. High concentrations of airborne particulate matter have been observed in this area. The collected samples were analyzed for 34 elements by instrumental neutron activation analysis (INAA), and data on the elemental concentrations were obtained. High concentrations of fine particles of As, Br, Sb, V, and Zn were observed. It was further observed that these fine particles were originated predominantly from the wear of tires and brakes, and not from automobile exhaust emissions. (author)

Effects of particulate air pollution on human health. Statement of the German Society of Pneumology (DGP) on the discussion about fine particulate air pollution; Partikulaere Luftverunreinigung und ihre Folgen fuer die menschliche Gesundheit. Stellungnahme der deutschen Gesellschaft fuer Pneumologie (DGP) zur aktuellen Feinstaub-Diskussion

Energy Technology Data Exchange (ETDEWEB)

Voshaar, T.H. [Krankenhaus Bethanien, Moers (Germany). Zentrum fuer Schlafmedizin und Heimbeatmung; Heyder, J. [GSF Inst. fuer Inhalationsbiologie, Neuherberg/Muenchen (Germany); Koehler, D. [Fachkrankenhaus Kloster Grafschaft, Schmallenberg (Germany); Krug, N. [Fraunhofer-Inst. Toxikologie und Experimentelle Medizin, Hannover (Germany); Nowak, D. [Inst. und Poliklinik fuer Arbeits- und Umweltmedizin, Ludwig-Maximilians-Univ., Muenchen (Germany); Scheuch, G. [Inamed GmbH, Muenchen-Gauting und Gemuenden/Wohra (Germany); Schulz, H. [GSF Inst. fuer Inhalationsbiologie, Neuherberg/Muenchen (Germany); Witt, C. [Charite-Universitaetsklinik, Schwerpunkt Pneumologie, Berlin (Germany)

2005-07-01

The statement of the German Society of Pneumology (DGP) on the discussion about fine particulate air pollution reviews recent research on the matter: effects of particulates depending on particle size, abundance indoor and outdoor, tobacco smoke, diesel soot particles, health hazards especially for children, epidemiology, toxicological studies, aerosols. (uke)

Thermodynamics of strongly coupled repulsive Yukawa particles in ambient neutralizing plasma: Thermodynamic instability and the possibility of observation in fine particle plasmas

International Nuclear Information System (INIS)

Totsuji, Hiroo

2008-01-01

The thermodynamics is analyzed for a system composed of particles with hard cores, interacting via the repulsive Yukawa potential (Yukawa particulates), and neutralizing ambient (background) plasma. An approximate equation of state is given with proper account of the contribution of ambient plasma and it is shown that there exists a possibility for the total isothermal compressibility of Yukawa particulates and ambient plasma to diverge when the coupling between Yukawa particulates is sufficiently strong. In this case, the system undergoes a transition into separated phases with different densities and we have a critical point for this phase separation. Examples of approximate phase diagrams related to this transition are given. It is emphasized that the critical point can be in the solid phase and we have the possibility to observe a solid-solid phase separation. The applicability of these results to fine particle plasmas is investigated. It is shown that, though the values of the characteristic parameters are semiquantitative due to the effects not described by this model, these phenomena are expected to be observed in fine particle plasmas, when approximately isotropic bulk systems are realized with a very strong coupling between fine particles.

Thermodynamics of strongly coupled repulsive Yukawa particles in ambient neutralizing plasma: Thermodynamic instability and the possibility of observation in fine particle plasmas

Science.gov (United States)

Totsuji, Hiroo

2008-07-01

The thermodynamics is analyzed for a system composed of particles with hard cores, interacting via the repulsive Yukawa potential (Yukawa particulates), and neutralizing ambient (background) plasma. An approximate equation of state is given with proper account of the contribution of ambient plasma and it is shown that there exists a possibility for the total isothermal compressibility of Yukawa particulates and ambient plasma to diverge when the coupling between Yukawa particulates is sufficiently strong. In this case, the system undergoes a transition into separated phases with different densities and we have a critical point for this phase separation. Examples of approximate phase diagrams related to this transition are given. It is emphasized that the critical point can be in the solid phase and we have the possibility to observe a solid-solid phase separation. The applicability of these results to fine particle plasmas is investigated. It is shown that, though the values of the characteristic parameters are semiquantitative due to the effects not described by this model, these phenomena are expected to be observed in fine particle plasmas, when approximately isotropic bulk systems are realized with a very strong coupling between fine particles.

Construction of Fine Particles Source Spectrum Bank in Typical Region and Empirical Research of Matching Diagnosis

Science.gov (United States)

Wang, Xing; Sun, Wenliang; Guo, Min; Li, Minjiao; Li, Wan

2018-01-01

The research object of this paper is fine particles in typical region. The construction of component spectrum bank is based on the technology of online source apportionment, then the result of the apportionment is utilized to verify the effectiveness of fine particles component spectrum bank and which also act as the matching basis of online source apportionment receptor sample. On the next, the particle source of air pollution is carried through the matching diagnosis empirical research by utilizing online source apportionment technology, to provide technical support for the cause analysis and treatment of heavy pollution weather.

The coercive force of fine particles of monoclinic pyrrhotite (Fe7S8 ...

African Journals Online (AJOL)

The temperature dependence of coercive force (Hc) between 77 K and 600 K has been investigated for fine particles of monoclinic pyrrhotite (Fe7S8) of < 1 mm and 1- 30 mm particle sizes. The study has shown that Hc is strongly dependent on temperature, as temperature rises above room temperature (293 K) to near the ...

Translocation and potential neurological effects of fine and ultrafine particles a critical update.

Science.gov (United States)

Peters, Annette; Veronesi, Bellina; Calderón-Garcidueñas, Lilian; Gehr, Peter; Chen, Lung Chi; Geiser, Marianne; Reed, William; Rothen-Rutishauser, Barbara; Schürch, Samuel; Schulz, Holger

2006-09-08

Particulate air pollution has been associated with respiratory and cardiovascular disease. Evidence for cardiovascular and neurodegenerative effects of ambient particles was reviewed as part of a workshop. The purpose of this critical update is to summarize the evidence presented for the mechanisms involved in the translocation of particles from the lung to other organs and to highlight the potential of particles to cause neurodegenerative effects. Fine and ultrafine particles, after deposition on the surfactant film at the air-liquid interface, are displaced by surface forces exerted on them by surfactant film and may then interact with primary target cells upon this displacement. Ultrafine and fine particles can then penetrate through the different tissue compartments of the lungs and eventually reach the capillaries and circulating cells or constituents, e.g. erythrocytes. These particles are then translocated by the circulation to other organs including the liver, the spleen, the kidneys, the heart and the brain, where they may be deposited. It remains to be shown by which mechanisms ultrafine particles penetrate through pulmonary tissue and enter capillaries. In addition to translocation of ultrafine particles through the tissue, fine and coarse particles may be phagocytized by macrophages and dendritic cells which may carry the particles to lymph nodes in the lung or to those closely associated with the lungs. There is the potential for neurodegenerative consequence of particle entry to the brain. Histological evidence of neurodegeneration has been reported in both canine and human brains exposed to high ambient PM levels, suggesting the potential for neurotoxic consequences of PM-CNS entry. PM mediated damage may be caused by the oxidative stress pathway. Thus, oxidative stress due to nutrition, age, genetics among others may increase the susceptibility for neurodegenerative diseases. The relationship between PM exposure and CNS degeneration can also be

Emissions and measure analysis of fine particles 2000-2020; Emissionen und Massnahmenanalyse Feinstaub 2000-2020

Energy Technology Data Exchange (ETDEWEB)

Joerss, Wolfram; Handke, Volker [Institut fuer Zukunftsstudien und Technologiebewertung gGmbH (IZT), Berlin (Germany)

2007-08-15

With this study, the Federal Environmental Agency's emission inventory on total suspended particles and the fine fractions PM{sub 1}0 and PM{sub 2}.5 was updated. On that basis, a reference scenario was developed for anthropogenic emissions of particulate matter up to the years 2010, 2015 and 2020. In addition, potential additional emission reduction measures were systematically collected and quantified. At the source groups which contribute most strongly to the emissions there are clear differences between the fine fractions and in the course of time. In particular, with the total fine the emission freight is very broadly distributed over many source groups. With PM{sub 2}.5, the emissions are more strongly concentrated on a limited number of source groups. The decrease of the emissions in the years between 2000 and 2020 in the reference scenario takes place in source groups with high portions of PM{sub 2}.5 of the emissions of total fine particles.

Emissions and measure analysis of fine particles 2000-2020; Emissionen und Massnahmenanalyse Feinstaub 2000-2020

Energy Technology Data Exchange (ETDEWEB)

Joerss, Wolfram; Handke, Volker [Institut fuer Zukunftsstudien und Technologiebewertung gGmbH (IZT), Berlin (Germany)

2007-08-15

With this study, the Federal Environmental Agency's emission inventory on total suspended particles and the fine fractions PM{sub 1}0 and PM{sub 2}.5 was updated. On that basis, a reference scenario was developed for anthropogenic emissions of particulate matter up to the years 2010, 2015 and 2020. In addition, potential additional emission reduction measures were systematically collected and quantified. At the source groups which contribute most strongly to the emissions there are clear differences between the fine fractions and in the course of time. In particular, with the total fine the emission freight is very broadly distributed over many source groups. With PM{sub 2}.5, the emissions are more strongly concentrated on a limited number of source groups. The decrease of the emissions in the years between 2000 and 2020 in the reference scenario takes place in source groups with high portions of PM{sub 2}.5 of the emissions of total fine particles.

Handbook on simultaneous x-ray and γ-ray ion beam methods for fine particle analysis

International Nuclear Information System (INIS)

Cohen, D.D.

2000-01-01

Sampling, measurement, characterisation and source appointment of fine atmospheric particles has become increasingly important in recent times. This is due in part to the realisation that the fine particle pollution caused by anthropogenic activities plays a key role in certain aspects of human health, pollution transport and global climate change. This publication discusses accelerator based ion beam analysis (IBA) methods of particle induced X-ray emission (PIXE) and particle induced γ-ray emission (PIGE) as applied to aerosol analysis. These techniques are sensitive, multielemental, mainly non-destructive, require no sample preparation, have short analysis times and can be used to analyse hundreds of filter samples a day in batch processing with minimum operator interaction. The aspects discussed in the publication include: the basics of the techniques; spectrum analysis; system calibration and blank subtraction; quantification; sensitivity; measurement errors

Particle identification by means of fine sampling dE/dX measurements

Energy Technology Data Exchange (ETDEWEB)

Imanishi, A; Ishii, T; Ohshima, T; Okuno, H; Shiino, K [Tokyo Univ., Tanashi (Japan). Inst. for Nuclear Study; Naito, F [Tokyo Univ. of Agriculture and Technology, Koganei (Japan). Faculty of Technology; Matsuda, T [Osaka Univ., Toyonaka (Japan). Faculty of Engineering Science

1983-04-01

Identification of relativistic charged particles by means of fine sampling d E/d X measurements with a longitudinal drift chamber has been studied. Using a fast-sampling ADC (25 MHz), dE/dX was measured in a 1.4 mm gas thickness over an electron drift space of 51 mm. For the simulated 1 m long tracks of pions and electrons of 500 MeV/c, a particle separation of 10sigma - 12sigma has been obtained, where sigma is the r.m.s. resolution of the dE/dX measurement. This result with fine sampling is better by a factor of 1.7 compared to the dE/dX measurement, with 21 mm sampling thickness. Further improvement achievable by reducing the correlation between neighbouring samples and simplification of electronics by use of the delta-ray clipping method are also discussed.

Characterization of road runoff with regard to seasonal variations, particle size distribution and the correlation of fine particles and pollutants.

Science.gov (United States)

Hilliges, R; Endres, M; Tiffert, A; Brenner, E; Marks, T

2017-03-01

Urban runoff is known to transport a significant pollutant load consisting of e.g. heavy metals, salts and hydrocarbons. Interactions between solid and dissolved compounds, proper understanding of particle size distribution, dissolved pollutant fractions and seasonal variations is crucial for the selection and development of appropriate road runoff treatment devices. Road runoff at an arterial road in Augsburg, Germany, has been studied for 3.5 years. A strong seasonal variation was observed, with increased heavy metal concentrations with doubled and tripled median concentrations for heavy metals during the cold season. Correlation analysis showed that de-icing salt is not the only factor responsible for increased pollutant concentrations in winter. During the cold period, the fraction of dissolved metals was lower compared to the warm season. In road dust, the highest metal concentrations were measured for fine particles. Metals in road runoff were found to show a significant correlation to fine particles SS63 (removal rates.

Impact of superplasticizer concentration and of ultra-fine particles on the rheological behaviour of dense mortar suspensions

International Nuclear Information System (INIS)

Artelt, C.; Garcia, E.

2008-01-01

This work aims at investigating the impact of the addition of superplasticizer and of ultra-fine particles, namely of silica fume and of precipitated titania, on the rheological behaviour of water-lean mortar pastes. The pastes are characterised in terms of their spread, their flowing behaviour and by means of performing a shear test, giving access to viscosity/shear gradient correlations. Adding superplasticizer is shown to shift the onset of shear thickening of the referring pastes to higher shear rates and to attenuate its otherwise rapid evolution, possibly by means of favouring steric particle-particle interactions. The workability of these mortars, which is characterised in terms of spread values and draining, is also improved. For the case of fly ash based mortars, adding ultra-fine particles is another way of (slightly) 'retarding' shear thickening and of attenuating its evolution, possibly because of resulting in - on the average - lower hydrodynamic forces and reduced attractive Van der Waals interactions between particles. However, at the same time these mortars are characterised by a worsening in workability which is attributed to the huge amount of surface area provided by the ultra-fines

HONO and Inorganic Fine Particle Composition in Typical Monsoon Region with Intensive Anthropogenic Emission: In-situ Observations and Source Identification.

Science.gov (United States)

Xie, Y.; Nie, W.; Ding, A.; Huang, X.

2015-12-01

Yangtze River Delta (YRD) is one of the most typical monsoon area with probably the most largest population intensity in the world. With sharply economic development and the large anthropogenic emissions, fine particle pollution have been one of the major air quality problem and may further have impact on the climate system. Though a lot of control policy (sulfur emission have been decreasing from 2007) have been conducted in the region, studies showed the sulfate in fine particles still take major fraction as the nitrate from nitrogen oxides increased significantly. In this study, the role of inorganic chemical compositions in fine particles was investigated with two years in-situ observation. Sulfate and Nitrate contribute to fine particle mass equally in general, but sulfate contributes more during summer and nitrate played more important role in winter. Using lagrangian dispersion backward modeling and source contribution clustering method, the impact of airmass coming from different source region (industrial, dust, biogenic emissions, etc) on fine particle inorganic compositions were discussed. Furthermore, we found two unique cases showing in-situ implications for sulfate formation by nitrogen dioxide oxidation mechanisms. It was showed that the mixing of anthropogenic pollutants with long-range transported mineral dust and biomass burning plume would enhance the sulfate formation by different chemistry mechanisms. This study focus on the complex aspects of fine particle formation in airmasses from different source regions: . It highlights the effect of NOx in enhancing the atmospheric oxidization capacity and indicates a potentially very important impact of increasing NOx on air pollution formation and regional climate change in East Asia.

Exposure to ultrafine particles, intracellular production of reactive oxygen species in leukocytes and altered levels of endothelial progenitor cells

DEFF Research Database (Denmark)

Jantzen, Kim; Møller, Peter Horn; Karottki, Dorina Gabriela

2016-01-01

. Additionally, the early endothelial progenitor cell levels were positively associated with a personalised measure of ultrafine particle exposure and negatively associated with both basal and capacity for reactive oxygen species production in lymphocytes and granulocytes, respectively. Our results indicate......Exposure to particles in the fine and ultrafine size range has been linked to induction of low-grade systemic inflammation, oxidative stress and development of cardiovascular diseases. Declining levels of endothelial progenitor cells within systemic circulation have likewise been linked...... to progression of cardiovascular diseases. The objective was to determine if exposure to fine and ultrafine particles from indoor and outdoor sources, assessed by personal and residential indoor monitoring, is associated with altered levels of endothelial progenitor cells, and whether such effects are related...

Characterizing Aggregated Exposure to Primary Particulate Matter: Recommended Intake Fractions for Indoor and Outdoor Sources

DEFF Research Database (Denmark)

Fantke, Peter; Jolliet, Olivier; Apte, Joshua Schulz

2017-01-01

Exposure to fine particulate matter (PM_(2.5)) from indoor and outdoor sources is a leading environmental contributor to global disease burden. In response, we established under the auspices of the UNEP/SETAC Life Cycle Initiative a coupled indoor-outdoor emission-to-exposure framework to provide...

The Influence of Soil Particle on Soil Condensation Water

OpenAIRE

Hou Xinwei; Chen Hao; Li Xiangquan; Cui Xiaomei; Liu Lingxia; Wang Zhenxing

2013-01-01

The experiment results showed that the indoor experiment formed from the volume of soil hygroscopic water increased gradually with decreasing size of soil particles. In the outdoor experiments, the results showed that the formed condensation water in medium sand was greater than it was in fine sand; the soil hot condensation water was mainly formed in the top layer of soil between 0-5 cm. We also found that covering the soil surface with stones can increase the volume of formed soil condensat...

A two-stage treatment for Municipal Solid Waste Incineration (MSWI) bottom ash to remove agglomerated fine particles and leachable contaminants.

Science.gov (United States)

Alam, Qadeer; Florea, M V A; Schollbach, K; Brouwers, H J H

2017-09-01

In this lab study, a two-stage treatment was investigated to achieve the valorization of a municipal solid waste incineration (MSWI) bottom ash fraction below 4mm. This fraction of MSWI bottom ash (BA) is the most contaminated one, containing potentially toxic elements (Cu, Cr, Mo and Sb), chlorides and sulfates. The BA was treated for recycling by separating agglomerated fine particles (≤125µm) and soluble contaminants by using a sequence of sieving and washing. Initially, dry sieving was performed to obtain BA-S (≤125µm), BA-M (0.125-1mm) and BA-L (1-4mm) fractions from the original sample. The complete separation of fine particles cannot be achieved by conventional sieving, because they are bound in a cementitious matrix around larger BA grains. Subsequently, a washing treatment was performed to enhance the liberation of the agglomerated fine particles from the BA-M and BA-L fractions. These fine particles were found to be similar to the particles of BA-S fraction in term of chemical composition. Furthermore, the leaching behavior of Cr, Mo Sb, chlorides and sulfates was investigated using various washing parameters. The proposed treatment for the separation of agglomerated fine particles with dry sieving and washing (L/S 3, 60min) was successful in bringing the leaching of contaminants under the legal limit established by the Dutch environmental norms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Outdoor air pollution and lung cancer: what now?

Directory of Open Access Journals (Sweden)

Enrico Pira

2013-12-01

Full Text Available In the last decade a substantial number of epidemiological studies suggested that outdoor air pollution and in particular respirable particulate matter (PM10 and fine particulate matter (PM2.5 are associated with an increased risk of lung cancer.The most recent is a multicentre European study...

Deviation from the superparamagnetic behaviour of fine-particle systems

CERN Document Server

Malaescu, I

2000-01-01

Studies concerning superparamagnetic behaviour of fine magnetic particle systems were performed using static and radiofrequency measurements, in the range 1-60 MHz. The samples were: a ferrofluid with magnetite particles dispersed in kerosene (sample A), magnetite powder (sample B) and the same magnetite powder dispersed in a polymer (sample C). Radiofrequency measurements indicated a maximum in the imaginary part of the complex magnetic susceptibility, for each of the samples, at frequencies with the magnitude order of tens of MHz, the origin of which was assigned to Neel-type relaxation processes. The static measurements showed a Langevin-type dependence of magnetisation M and of susceptibility chi, on the magnetic field for sample A. For samples B and C deviations from this type of dependence were found. These deviations were analysed qualitatively and explained in terms of the interparticle interactions, dispersion medium influence and surface effects.

Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation.

Science.gov (United States)

Jang, Min; Lee, Hyun-Ju; Shim, Yonsik

2010-04-01

The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 microm, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L(-1) FL-2949 (coagulant) and 12 mg L(-1) A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

Characteristics of Fine Particles in an Urban Atmosphere—Relationships with Meteorological Parameters and Trace Gases

Science.gov (United States)

Zhang, Tianhao; Zhu, Zhongmin; Gong, Wei; Xiang, Hao; Fang, Ruimin

2016-01-01

Atmospheric fine particles (diameter industrial emissions. To reveal the characteristics of fine particles in an industrial city of a developing country, two-year measurements of particle number size distribution (15.1 nm–661 nm), meteorological parameters, and trace gases were made in the city of Wuhan located in central China from June 2012 to May 2014. The annual average particle number concentrations in the nucleation mode (15.1 nm–30 nm), Aitken mode (30 nm–100 nm), and accumulation mode (100 nm–661 nm) reached 4923 cm−3, 12193 cm−3 and 4801 cm−3, respectively. Based on Pearson coefficients between particle number concentrations and meteorological parameters, precipitation and temperature both had significantly negative relationships with particle number concentrations, whereas atmospheric pressure was positively correlated with the particle number concentrations. The diurnal variation of number concentration in nucleation mode particles correlated closely with photochemical processes in all four seasons. At the same time, distinct growth of particles from nucleation mode to Aitken mode was only found in spring, summer, and autumn. The two peaks of Aitken mode and accumulation mode particles in morning and evening corresponded obviously to traffic exhaust emissions peaks. A phenomenon of “repeated, short-lived” nucleation events have been created to explain the durability of high particle concentrations, which was instigated by exogenous pollutants, during winter in a case analysis of Wuhan. Measurements of hourly trace gases and segmental meteorological factors were applied as proxies for complex chemical reactions and dense industrial activities. The results of this study offer reasonable estimations of particle impacts and provide references for emissions control strategies in industrial cities of developing countries. PMID:27517948

Briquetting of coal fines and sawdust - effect of particle-size distribution

Energy Technology Data Exchange (ETDEWEB)

Patil, D.P.; Taulbee, D.; Parekh, B.K.; Honaker, R. [University of Kentucky, Lexington, KY (United States). Center for Applied Energy Research

2009-07-01

The coal industry usually discards fine-size (-150 microns) coal because of its high-moisture content and handling problems. One avenue for utilization is to either pelletize or briquette this material. However, industry has not adopted this route due in large part to significant drying and binder costs. In an effort to reduce these costs, compacting and briquetting studies were conducted to determine the effect of combining a coarse (1.18x0.15mm) spiral separator product with a fine coal flotation product (-150microns), with and without adding sawdust. Maximizing the packing density of the coal and wood waste mixture could potentially reduce the binder requirement by minimizing the void space as well as reducing shipping costs. Accordingly, work reported here focused on evaluating the impact of the particle-size distribution of different blends of fine and coarse coal, with and without sawdust and/or binder. The modified Proctor density of compacted blends along with the porosity and compressive strengths of briquettes made from each blend were determined. For the coal-only blends, the packing density was maximized by a relatively high (70% to 80%) coarse coal content. However, the packing density did not correlate with the compressive strength of the briquette that instead maximized with 100% fine flotation coal and continuously decreased as higher proportions of coarse coal were added. Similar compaction and compressive-strength results were obtained with mixtures of sawdust and varying proportions of coarse and fine coal. With the addition of a binder, the highest strengths were no longer obtained with 100% fine coal but instead maximized between 20% and 50% coarse coal addition depending on how long the briquettes were cured.

Measurements of children's exposures to particles and nitrogen dioxide in Santiago, Chile

International Nuclear Information System (INIS)

Rojas-Bracho, Leonora; Suh, Helen H.; Koutrakis, Petros; Oyola, Pedro

2002-01-01

An exposure study of children (aged 10-12 years) living in Santiago, Chile, was conducted. Personal, indoor and outdoor fine and inhalable particulate matter ( 2.5 and 10 , respectively), and nitrogen dioxide (NO 2 ) were measured during pilot (N=8) and main (N=20) studies, which were conducted during the winters of 1998 and 1999, respectively. For the main study, personal indoor and outdoor 24-h samples were collected for five consecutive days. Similar mean personal, indoor and outdoor PM 2.5 concentrations (69.5, 68.5 and 68.1 μg m -3 , respectively) were found. However, for coarse particles (calculated as the difference between measured PM 10 and PM 2.5 , PM 2.5-10 ) indoor and outdoor levels (35.4 and 47.4 μg m -3 ) were lower than their corresponding personal exposures (76.3 μg m -3 ). Indoor and outdoor NO 2 concentrations were comparable (35.8 and 36.9 ppb) and higher than personal exposures (25.9 ppb). Very low ambient indoor and personal O 3 levels were found, which were mostly below the method's limit of detection (LOD). Outdoor particles contributed significantly to indoor concentrations, with effective penetration efficiencies of 0.61 and 0.30 for PM 2.5 and PM 2.5-10 , respectively. Personal exposures were strongly associated with indoor and outdoor concentrations for PM 2.5 , but weakly associated for PM 2.5-10 . For NO 2 , weak associations were obtained for indoor-outdoor and personal-outdoor relationships. This is probably a result of the presence of gas cooking stoves in all the homes. Median I/O, P/I and P/O ratios for PM 2.5 were close to unity, and for NO 2 they ranged between 0.64 and 0.95. These ratios were probably due to high ambient PM 2.5 and NO 2 levels in Santiago, which diminished the relative contribution of indoor sources and subjects' activities to indoor and personal PM 2.5 and NO 2 levels

Mathematical Model of Transfer and Deposition of Finely Dispersed Particles in a Turbulent Flow of Emulsions and Suspensions

Science.gov (United States)

Laptev, A. G.; Basharov, M. M.

2018-05-01

The problem of modeling turbulent transfer of finely dispersed particles in liquids has been considered. An approach is used where the transport of particles is represented in the form of a variety of the diffusion process with the coefficient of turbulent transfer to the wall. Differential equations of transfer are written for different cases, and a solution of the cell model is obtained for calculating the efficiency of separation in a channel. Based on the theory of turbulent transfer of particles and of the boundary layer model, an expression has been obtained for calculating the rate of turbulent deposition of finely dispersed particles. The application of this expression in determining the efficiency of physical coagulation of emulsions in different channels and on the surface of chaotic packings is shown.

Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation

Energy Technology Data Exchange (ETDEWEB)

Jang, M.; Lee, H.J.; Shim, Y. [Korean Mine Reclamation Corporation MIRECO, Seoul (Republic of Korea)

2010-07-01

The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 {mu} m, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L{sup -1} FL-2949 (coagulant) and 12 mg L{sup -1} A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

NANODERM. Quality of skin as a barrier to ultra-fine particles

International Nuclear Information System (INIS)

Kiss, A.Z.; Kertesz, Zs.; Szikszai, Z.; Biro, T.; Czifra, G.; Toth, B.I.; Juhasz, I.; Kiss, B.; Hunyadi, J.

2007-01-01

Complete text of publication follows. The EU5 project carried out by a consortium of 12 European universities and research institutes under the leadership of the Faculty of Physics and Geosciences, University of Leipzig started in 2003 and ended with the publication of its final report in 2007. The main goal of the project was to get quantitative information on the penetration of ultra-fine particles in all strata of skin, on their penetration pathways as well as on their impact on human health. Details of the project can be found on the following website: http://www.uni-leipzig.de/"~nanoderm. The Hungarian team was lead by the Department of Dermatology, University of Debrecen, who provided human skin grafted on SCID (Severe Combined Immune Deficiency) mice as a suitable model for studying particle penetration. In the Institute of Physiology, University of Debrecen, the cellular effects of the nanoparticles were assessed. The ATOMKI group performed ion beam analytical investigations using proton induced x-ray emission and scanning transmission ion microscopy techniques to determine the particle distribution on porcine, SCID graft and human skin samples on which various nanoparticle (TiO 2 ) formulations including commercially available sunscreens were applied. Several pre-treatments of the skin were tested, too. The skin samples were cryofixed native specimens, reducing considerably the possibility of creating artefacts. Results Titanium was only detected in the stratum corneum for healthy skin. Penetration to layers consisting of living cells was not observed. No diffusion profile was present therefore we conclude that the penetration takes place through mechanical action. Deep penetration into hair follicles was also observed, but not into vital tissue. Clearance is expected via desquamation and sebum excretion respectively for corneocyte layers and hair follicles. In conclusion, the NANODERM group does not expect any harmful effects of sunscreens containing

Influence of ambient (outdoor) sources on residential indoor and personal PM2.5 concentrations: analyses of RIOPA data.

Science.gov (United States)

Meng, Qing Yu; Turpin, Barbara J; Korn, Leo; Weisel, Clifford P; Morandi, Maria; Colome, Steven; Zhang, Junfeng Jim; Stock, Thomas; Spektor, Dalia; Winer, Arthur; Zhang, Lin; Lee, Jong Hoon; Giovanetti, Robert; Cui, William; Kwon, Jaymin; Alimokhtari, Shahnaz; Shendell, Derek; Jones, Jennifer; Farrar, Corice; Maberti, Silvia

2005-01-01

The Relationship of Indoor, Outdoor and Personal Air (RIOPA) study was designed to investigate residential indoor, outdoor and personal exposures to several classes of air pollutants, including volatile organic compounds, carbonyls and fine particles (PM2.5). Samples were collected from summer, 1999 to spring, 2001 in Houston (TX), Los Angeles (CA) and Elizabeth (NJ). Indoor, outdoor and personal PM2.5 samples were collected at 212 nonsmoking residences, 162 of which were sampled twice. Some homes were chosen due to close proximity to ambient sources of one or more target analytes, while others were farther from sources. Median indoor, outdoor and personal PM2.5 mass concentrations for these three sites were 14.4, 15.5 and 31.4 microg/m3, respectively. The contributions of ambient (outdoor) and nonambient sources to indoor and personal concentrations were quantified using a single compartment box model with measured air exchange rate and a random component superposition (RCS) statistical model. The median contribution of ambient sources to indoor PM2.5 concentrations using the mass balance approach was estimated to be 56% for all study homes (63%, 52% and 33% for California, New Jersey and Texas study homes, respectively). Reasonable variations in model assumptions alter median ambient contributions by less than 20%. The mean of the distribution of ambient contributions across study homes agreed well for the mass balance and RCS models, but the distribution was somewhat broader when calculated using the mass balance model with measured air exchange rates.

The heavy metal partition in size-fractions of the fine particles in agricultural soils contaminated by waste water and smelter dust

Energy Technology Data Exchange (ETDEWEB)

Zhang, Haibo, E-mail: hbzhang@yic.ac.cn [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Luo, Yongming, E-mail: ymluo@yic.ac.cn [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Makino, Tomoyuki [National Institute for Agro-Environmental Sciences, Tsukuba 3058604 (Japan); Wu, Longhua [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Nanzyo, Masami [Tohoku University, Sendai 9808576 (Japan)

2013-03-15

Highlights: ► A continuous flow ultra-centrifugation method has been developed to obtain fine particles from polluted agricultural soil. ► Pollution source affected the heavy metal fractionation in size-fractions by changing soil particle properties. ► The iron oxides affected the distribution of lead species more than other metals in the smelter dust polluted particles. -- Abstract: The partitioning of pollutant in the size-fractions of fine particles is particularly important to its migration and bioavailability in soil environment. However, the impact of pollution sources on the partitioning was seldom addressed in the previous studies. In this study, the method of continuous flow ultra-centrifugation was developed to separate three size fractions (<1 μm, <0.6 μm and <0.2 μm) of the submicron particles from the soil polluted by wastewater and smelter dust respectively. The mineralogy and physicochemical properties of each size-fraction were characterized by X-ray diffraction, transmission electron microscope etc. Total content of the polluted metals and their chemical speciation were measured. A higher enrichment factor of the metals in the fractions of <1 μm or less were observed in the soil contaminated by wastewater than by smelter dust. The organic substance in the wastewater and calcite from lime application were assumed to play an important role in the metal accumulation in the fine particles of the wastewater polluted soil. While the metal accumulation in the fine particles of the smelter dust polluted soil is mainly associated with Mn oxides. Cadmium speciation in both soils is dominated by dilute acid soluble form and lead speciation in the smelter dust polluted soil is dominated by reducible form in all particles. This implied that the polluted soils might be a high risk to human health and ecosystem due to the high bioaccessblity of the metals as well as the mobility of the fine particles in soil.

The heavy metal partition in size-fractions of the fine particles in agricultural soils contaminated by waste water and smelter dust

International Nuclear Information System (INIS)

Zhang, Haibo; Luo, Yongming; Makino, Tomoyuki; Wu, Longhua; Nanzyo, Masami

2013-01-01

Highlights: ► A continuous flow ultra-centrifugation method has been developed to obtain fine particles from polluted agricultural soil. ► Pollution source affected the heavy metal fractionation in size-fractions by changing soil particle properties. ► The iron oxides affected the distribution of lead species more than other metals in the smelter dust polluted particles. -- Abstract: The partitioning of pollutant in the size-fractions of fine particles is particularly important to its migration and bioavailability in soil environment. However, the impact of pollution sources on the partitioning was seldom addressed in the previous studies. In this study, the method of continuous flow ultra-centrifugation was developed to separate three size fractions (<1 μm, <0.6 μm and <0.2 μm) of the submicron particles from the soil polluted by wastewater and smelter dust respectively. The mineralogy and physicochemical properties of each size-fraction were characterized by X-ray diffraction, transmission electron microscope etc. Total content of the polluted metals and their chemical speciation were measured. A higher enrichment factor of the metals in the fractions of <1 μm or less were observed in the soil contaminated by wastewater than by smelter dust. The organic substance in the wastewater and calcite from lime application were assumed to play an important role in the metal accumulation in the fine particles of the wastewater polluted soil. While the metal accumulation in the fine particles of the smelter dust polluted soil is mainly associated with Mn oxides. Cadmium speciation in both soils is dominated by dilute acid soluble form and lead speciation in the smelter dust polluted soil is dominated by reducible form in all particles. This implied that the polluted soils might be a high risk to human health and ecosystem due to the high bioaccessblity of the metals as well as the mobility of the fine particles in soil

Modeling indoor air pollution of outdoor origin in homes of SAPALDIA subjects in Switzerland.

Science.gov (United States)

Meier, Reto; Schindler, Christian; Eeftens, Marloes; Aguilera, Inmaculada; Ducret-Stich, Regina E; Ineichen, Alex; Davey, Mark; Phuleria, Harish C; Probst-Hensch, Nicole; Tsai, Ming-Yi; Künzli, Nino

2015-09-01

Given the shrinking spatial contrasts in outdoor air pollution in Switzerland and the trends toward tightly insulated buildings, the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) needs to understand to what extent outdoor air pollution remains a determinant for residential indoor exposure. The objectives of this paper are to identify determining factors for indoor air pollution concentrations of particulate matter (PM), ultrafine particles in the size range from 15 to 300nm, black smoke measured as light absorbance of PM (PMabsorbance) and nitrogen dioxide (NO2) and to develop predictive indoor models for SAPALDIA. Multivariable regression models were developed based on indoor and outdoor measurements among homes of selected SAPALDIA participants in three urban (Basel, Geneva, Lugano) and one rural region (Wald ZH) in Switzerland, various home characteristics and reported indoor sources such as cooking. Outdoor levels of air pollutants were important predictors for indoor air pollutants, except for the coarse particle fraction. The fractions of outdoor concentrations infiltrating indoors were between 30% and 66%, the highest one was observed for PMabsorbance. A modifying effect of open windows was found for NO2 and the ultrafine particle number concentration. Cooking was associated with increased particle and NO2 levels. This study shows that outdoor air pollution remains an important determinant of residential indoor air pollution in Switzerland. Copyright © 2015 Elsevier Ltd. All rights reserved.

Chemical Characterization of Outdoor and Subway Fine (PM2.5-1.0) and Coarse (PM10-2.5) Particulate Matter in Seoul (Korea) Computer-Controlled Scanning Electron Microscopy (CCSEM)

Science.gov (United States)

Outdoor and indoor (subway) samples were collected by passive sampling in urban Seoul and analyzed with computer-controlled scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (CCSEM-EDX). Soil/road dust particles accounted for 42-60% (by weight) of fin...

Metallic nickel nano- and fine particles induce JB6 cell apoptosis through a caspase-8/AIF mediated cytochrome c-independent pathway

Directory of Open Access Journals (Sweden)

Castranova Vincent

2009-04-01

Full Text Available Abstract Background Carcinogenicity of nickel compounds has been well documented. However, the carcinogenic effect of metallic nickel is still unclear. The present study investigates metallic nickel nano- and fine particle-induced apoptosis and the signal pathways involved in this process in JB6 cells. The data obtained from this study will be of benefit for elucidating the pathological and carcinogenic potential of metallic nickel particles. Results Using 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay, we found that metallic nickel nanoparticles exhibited higher cytotoxicity than fine particles. Both metallic nickel nano- and fine particles induced JB6 cell apoptosis. Metallic nickel nanoparticles produced higher apoptotic induction than fine particles. Western-blot analysis showed an activation of proapoptotic factors including Fas (CD95, Fas-associated protein with death domain (FADD, caspase-8, death receptor 3 (DR3 and BID in apoptotic cells induced by metallic nickel particles. Immunoprecipitation (IP western blot analysis demonstrated the formation of the Fas-related death-inducing signaling complex (DISC in the apoptotic process. Furthermore, lamin A and beta-actin were cleaved. Moreover, we found that apoptosis-inducing factor (AIF was up-regulated and released from mitochondria to cytoplasm. Interestingly, although an up-regulation of cytochrome c was detected in the mitochondria of metallic nickel particle-treated cells, no cytochrome c release from mitochondria to cytoplasm was found. In addition, activation of antiapoptotic factors including phospho-Akt (protein kinase B and Bcl-2 was detected. Further studies demonstrated that metallic nickel particles caused no significant changes in the mitochondrial membrane permeability after 24 h treatment. Conclusion In this study, metallic nickel nanoparticles caused higher cytotoxicity and apoptotic induction than fine particles in JB6 cells. Apoptotic cell death

Associations of outdoor air pollution with hemorrhagic stroke mortality.

Science.gov (United States)

Yorifuji, Takashi; Kawachi, Ichiro; Sakamoto, Tetsuro; Doi, Hiroyuki

2011-02-01

Evidence linking short-term exposure to outdoor air pollution with hemorrhagic stroke is inconsistent. We evaluated the associations between outdoor air pollution and specific types of stroke in Tokyo, Japan, from April 2003 to December 2008. We obtained daily counts of stroke mortality (n = 41,440) and concentrations of nitrogen dioxide as well as particles less than 2.5 μm in diameter. Time-series analysis was employed. Although same-day air pollutants were positively associated with ischemic stroke and intracerebral hemorrhage mortality, both air pollutants were more strongly associated with subarachnoid hemorrhage mortality: rate ratio was 1.041 (95% confidence interval: 1.011-1.072) for each 10 μg/m3 increase in the previous-day particles less than 2.5 μm. This study suggests that short-term exposure to outdoor air pollution increases the risks of hemorrhagic stroke mortality as well as ischemic stroke mortality.

Synthesis of AlN fine particles by surface corona discharge-CVD; Enmen corona hoden CVD ni yoru AlN biryushi no gosei

Energy Technology Data Exchange (ETDEWEB)

Oyama, Y.; Chiba, S. [Hokkaido National Industrial Research Institute, Sapporo (Japan); Harima, K> ; Kondo, K.; Shinohara, K. [Hokkaido University, Sapporo (Japan)

1994-09-15

With an objective to improve insulating and heat dissipating substrates substituting for the conventional alumina substrates, discussions been given on synthesis of AlN fine particles by means of gaseous phase reaction between AlCl3 and NH3 using surface corona discharge as a reaction exciting source. AIN particles should be highly pure to acquire high-heat conductivity, and fine and uniform particles to obtain dense sinters at low temperatures. The particles obtained by using the present method were amorphous particles having nearly spherical form and smooth surface. The particle diameter depends on the initial concentration of AlCl3, and is proportional to 0.4 square of the concentration. Within the range in the present experiment, the diameters ranged from 208 nm to 431 nm. The particle diameter increased in proportion to 0.2 square of an average gas stagnating time within the plasma generating region. The particle size distribution consisted of highly uniform fine particles having the standard deviation at about the same degree as that in the conventional thermal CVD process. The alumina-based oxygen was removed completely by reduction due to graphite powder, but the re-oxidation during removal of the remaining graphite using combustion had oxygen remained at 7.4% by weight. 16 refs., 7 figs.

A comparative study of the number and mass of fine particles emitted with diesel fuel and marine gas oil (MGO)

Science.gov (United States)

Nabi, Md. Nurun; Brown, Richard J.; Ristovski, Zoran; Hustad, Johan Einar

2012-09-01

The current investigation reports on diesel particulate matter emissions, with special interest in fine particles from the combustion of two base fuels. The base fuels selected were diesel fuel and marine gas oil (MGO). The experiments were conducted with a four-stroke, six-cylinder, direct injection diesel engine. The results showed that the fine particle number emissions measured by both SMPS and ELPI were higher with MGO compared to diesel fuel. It was observed that the fine particle number emissions with the two base fuels were quantitatively different but qualitatively similar. The gravimetric (mass basis) measurement also showed higher total particulate matter (TPM) emissions with the MGO. The smoke emissions, which were part of TPM, were also higher for the MGO. No significant changes in the mass flow rate of fuel and the brake-specific fuel consumption (BSFC) were observed between the two base fuels.

Radon parameters in outdoor air

International Nuclear Information System (INIS)

Porstendoerfer, J.; Zock, Ch.; Wendt, J.; Reineking, A.

2002-01-01

For dose estimation by inhalation of the short lived radon progeny in outdoor air, the equilibrium factor (F), the unattached fraction (f p ), and the activity size distribution of the radon progeny were measured. Besides the radon parameter the meteorological parameter like temperature, wind speed, and rainfall intensity were registered. The measurements were carried out continuously for several weeks to find out the variation with time (day/night) and for different weather conditions. The radon gas, the unattached and aerosol-attached radon progenies were measured with an monitor developed for continuous measurements in outdoor air with low activity concentrations. For the determination of the activity size distribution a low pressure online alpha cascade impactor was used. The measured values of the equilibrium factor varied between 0.5-0.8 depending on weather conditions and time of the day. For high pressure weather conditions a diurnal variation of the F-factor was obtained. A lower average value (F=0.25) was registered during rainy days. The obtained f p -values varied between 0.04 and 0.12. They were higher than expected. The measured activity size distribution of the radon progeny averaged over a measurement period of three weeks can be approximated by a sum of three log-normal distributions. The greatest activity fraction is adsorbed on aerosol particles in the accumulation size range (100-1000 nm) with activity median diameters and geometric standard deviation values between 250-450 nm and 1.5-3.0, respectively. The activity median diameter of this accumulation mode in outdoor air was significantly greater than in indoor air (150-250 nm). An influence of the weather conditions on the activity of the accumulation particles was not significant. In contrast to the results of measurements in houses a small but significant fraction of the radon progeny (average value: 2%) is attached on coarse particles (>1000 nm). This fraction varied between 0-10%. 20

Fine hematite particles of Martian interest: absorption spectra and optical constants

International Nuclear Information System (INIS)

Marra, A C; Blanco, A; Fonti, S; Jurewicz, A; Orofino, V

2005-01-01

Hematite is an iron oxide very important for the study of climatic evolution of Mars. It can occur in two forms: red and grey, mainly depending on the granulometry of the samples. Spectra of bright regions of Mars suggest the presence of red hematite particles. Moreover the Thermal Emission Spectrometer (TES), on board the Mars Global Surveyor mission, has discovered a deposit of crystalline grey hematite in Sinus Meridiani. TES spectra of that Martian region exhibit features at about 18, 23 and 33 μm that are consistent with hematite. Coarse grey hematite is considered strong evidence for longstanding water, while it is unknown whether the formation of fine-grained red hematite requires abundant water. Studies are needed in order to further characterize the spectral properties of the two kinds of hematite. For this reason we have analyzed a sample of submicron hematite particles in the 6.25-50 μm range in order to study the influence of particles size and shape on the infrared spectra. The optical constants of a particulate sample have been derived and compared with published data concerning bulk samples of hematite. Our results seem to indicate that particle shape is an important factor to take into account for optical constants derivation

The additive association of indoor cigarette and marijuana smoking on potential exposure to fine particles

OpenAIRE

Posis, Alexander Ivan; Klepeis, Neil; Bellettiere, John; Liles, Sandy; Berardi, Vincent; Nguyen, Ben; Hughes, Suzanne; Hovell, Melbourne

2017-01-01

Air particle monitors were placed in 298 homes of families with at least 1 cigarette smoker and 1 child under the age of 14. After monitors continuously measured fine particle counts (0.5 to 2.5 microns) for at least 7 days, participants were interviewed about past 7-day frequency of cigarette and marijuana smoking, other PGEs (e.g., burning candles, burning food) and ventilation activities such as use of exhaust fans. Dichotomized survey responses (any vs. none) from 193 ho...

Characterization of ultrafine and fine particles from CHP Plants

Energy Technology Data Exchange (ETDEWEB)

2009-08-15

Samples of particles collected at CHP plants in the project 'Survey of emissions from CHP Plants' have been analysed in this project to give information on the morphology and chemical composition of individual particle size classes. The objective of this project was to characterize ultrafine and fine particles emitted to the atmosphere from Danish CHP plants. Nine CHP plants were selected in the Emission Survey Project as being representative for the different types of CHP plants operating in Denmark: 1) Three Waste-to Energy (WTE) plants. 2) Three biomass fired (BM) plants (two straw fired, one wood/saw dust fired). 3) Two gas fired (GF) plants (one natural gas, one landfill gas fired). 4) One gasoil (GO) fired plant. At the WTE and BM plants, various types of emission control systems implemented. The results from these plants represent the composition and size distribution of combustion particles that are emitted from the plants emission control systems. The measured emissions of particles from the waste-to-energy plants WTE1-3 are generally very low. The number and mass concentrations of ultrafine particles (PM{sub 0.1}) were particularly low in the flue gas from WTE2 and WTE3, where bag filters are used for the reduction of particle emissions. The EDX analysis of particles from the WTE plants indicates that the PM{sub 0.1} that penetrates the ECS at WTE can contain high fractions of metals such as Fe, Mn and Cu. The SEM analysis of particles from WTE1-3 showed that the particles were generally porous and irregular in shape. The concentrations of particles in the flue gas from the biomass plants were generally higher than found for the WTE plants. The time series results showed that periodical, high concentration peaks of PM emissions occur from BM1 and BM2. The chemical composition of the particles emitted from the three biomass plants is generally dominated by C, O and S, and to some extend also Fe and Si. A high amount of Cu was found in selected

Air ion concentrations in various urban outdoor environments

Science.gov (United States)

Ling, Xuan; Jayaratne, Rohan; Morawska, Lidia

2010-06-01

Atmospheric ions are produced by many natural and anthropogenic sources and their concentrations vary widely between different environments. There is very little information on their concentrations in different types of urban environments, how they compare across these environments and their dominant sources. In this study, we measured airborne concentrations of small ions, particles and net particle charge at 32 different outdoor sites in and around a major city in Australia and identified the main ion sources. Sites were classified into seven groups as follows: park, woodland, city centre, residential, freeway, power lines and power substation. Generally, parks were situated away from ion sources and represented the urban background value of about 270 ions cm -3. Median concentrations at all other groups were significantly higher than in the parks. We show that motor vehicles and power transmission systems are two major ion sources in urban areas. Power lines and substations constituted strong unipolar sources, while motor vehicle exhaust constituted strong bipolar sources. The small ion concentration in urban residential areas was about 960 cm -3. At sites where ion sources were co-located with particle sources, ion concentrations were inhibited due to the ion-particle attachment process. These results improved our understanding on air ion distribution and its interaction with particles in the urban outdoor environment.

[Evaluation of Cellular Effects Caused by Lunar Regolith Simulant Including Fine Particles].

Science.gov (United States)

Horie, Masanori; Miki, Takeo; Honma, Yoshiyuki; Aoki, Shigeru; Morimoto, Yasuo

2015-06-01

The National Aeronautics and Space Administration has announced a plan to establish a manned colony on the surface of the moon, and our country, Japan, has declared its participation. The surface of the moon is covered with soil called lunar regolith, which includes fine particles. It is possible that humans will inhale lunar regolith if it is brought into the spaceship. Therefore, an evaluation of the pulmonary effects caused by lunar regolith is important for exploration of the moon. In the present study, we examine the cellular effects of lunar regolith simulant, whose components are similar to those of lunar regolith. We focused on the chemical component and particle size in particular. The regolith simulant was fractionated to lunar regolith simulant such as cell membrane damage, induction of oxidative stress and proinflammatory effect.

Indoor organic and inorganic pollutants: In-situ formation and dry deposition in Southeastern Brazil

Science.gov (United States)

Allen, Andrew G.; Miguel, Antonio H.

We have measured indoor and outdoor levels of particle- and gas-phase pollutants, collected in offices, restaurants and a hotel at six different sites in and around the cities of São Paulo and Campinas, Brazil, during summer 1993. Gas-phase species included acetic acid, formic acid, nitrous acid, hydrochloric acid, sulfur dioxide, nitric acid, oxalic acid, and pyruvic acid. Fine mode ( 3 μm dp) species measured included chloride, potassium, acetate, nitrate, magnesium, formate, sodium, pyruvate, nitrite, calcium, sulfate, oxalate, and ammonium. One sample (˜ 6 h) was simultaneously collected indoors and outdoors at each site during regular working hours. Indoor samplers were located ca. 1.5 m from the floor, and the outdoors immediately outside the window. Indoor/outdoor concentration ratios suggest that fine potassium chloride was produced indoors in appreciable amounts at both restaurants studied and, to a lesser extent, in the three offices as well. Indoor fine nitrate particles found in restaurants appear to have been produced by fuel combustion; a small fraction may have resulted from dry deposition of nitric acid onto existing fine particles. Indoor and outdoor concentrations of fine- and coarse-mode acetate suggest their production at all sites. The average concentration of gas-phase acetic acid was 42 μg m -3 indoors compared to 9.0 μg m -3 outdoors. In-situ formation of nitrous acid and acetic acid appears to have occurred at all indoor sites. High levels of formic and acetic acids were produced indoors at a pizzeria that used wood for cooking. Nitrous acid average concentrations for all sites were 8.4 μm m -3 indoors and 3.2 μm m -3 outdoors. Indoor/outdoor ratios at all sites suggest that dry deposition indoors may have occurred for hydrochloric acid, nitric acid and sulfur dioxide and that fine-mode sulfate infiltrate buildings from outside at most sites.

Cooling of an internal-heated debris bed with fine particles

International Nuclear Information System (INIS)

Yang, Z.L.; Sehgal, B.R.

2001-01-01

In this paper, an analytical model on dryout heat flux of ex-vessel debris beds with fines particles under top flooding conditions has been developed. The parametric study is performed on the effect of the stratification of the debris beds on the dryout heat flux. The calculated results show that the stratification configuration of the debris beds with smaller particles and lower porosity layer resting on the top of another layer of the beds has profound effect on the dryout heat flux for the debris beds both with and without a downcomer. The enhancement of the dryout heat flux by the downcomer is significant. The efficiency of the single downcomer on the enhancement of the dryout heat flux is also analyzed. This, in general, agrees well with experimental data. The model is also employed to perform the assessment on the coolability of the ex-vessel debris bed under representative accidental conditions. One conservative case is chosen, and it is found that the downcomer could be efficient measure to cool the debris bed and hence terminate the severe accident. (authors)

Measurements of children's exposures to particles and nitrogen dioxide in Santiago, Chile

Energy Technology Data Exchange (ETDEWEB)

Rojas-Bracho, Leonora; Suh, Helen H.; Koutrakis, Petros [Harvard University, School of Public Health, 665 Huntington Avenue, 02115 Boston, MA (United States); Oyola, Pedro [Comision Nacional del Medio Ambiente CONAMA, Santiago (Chile)

2002-03-27

An exposure study of children (aged 10-12 years) living in Santiago, Chile, was conducted. Personal, indoor and outdoor fine and inhalable particulate matter (<2.5 {mu}m in diameter, PM{sub 2.5} and <10 {mu}m in diameter, PM{sub 10}, respectively), and nitrogen dioxide (NO{sub 2}) were measured during pilot (N=8) and main (N=20) studies, which were conducted during the winters of 1998 and 1999, respectively. For the main study, personal indoor and outdoor 24-h samples were collected for five consecutive days. Similar mean personal, indoor and outdoor PM{sub 2.5} concentrations (69.5, 68.5 and 68.1 {mu}g m{sup -3}, respectively) were found. However, for coarse particles (calculated as the difference between measured PM{sub 10} and PM{sub 2.5}, PM{sub 2.5-10}) indoor and outdoor levels (35.4 and 47.4 {mu}g m{sup -3}) were lower than their corresponding personal exposures (76.3 {mu}g m{sup -3}). Indoor and outdoor NO{sub 2} concentrations were comparable (35.8 and 36.9 ppb) and higher than personal exposures (25.9 ppb). Very low ambient indoor and personal O{sub 3} levels were found, which were mostly below the method's limit of detection (LOD). Outdoor particles contributed significantly to indoor concentrations, with effective penetration efficiencies of 0.61 and 0.30 for PM{sub 2.5} and PM{sub 2.5-10}, respectively. Personal exposures were strongly associated with indoor and outdoor concentrations for PM{sub 2.5}, but weakly associated for PM{sub 2.5-10}. For NO{sub 2}, weak associations were obtained for indoor-outdoor and personal-outdoor relationships. This is probably a result of the presence of gas cooking stoves in all the homes. Median I/O, P/I and P/O ratios for PM{sub 2.5} were close to unity, and for NO{sub 2} they ranged between 0.64 and 0.95. These ratios were probably due to high ambient PM{sub 2.5} and NO{sub 2} levels in Santiago, which diminished the relative contribution of indoor sources and subjects' activities to indoor and personal PM

Toxicity and elemental composition of particulate matter from outdoor and indoor air of elementary schools in Munich, Germany.

Science.gov (United States)

Oeder, S; Dietrich, S; Weichenmeier, I; Schober, W; Pusch, G; Jörres, R A; Schierl, R; Nowak, D; Fromme, H; Behrendt, H; Buters, J T M

2012-04-01

Outdoor particulate matter (PM(10)) is associated with detrimental health effects. However, individual PM(10) exposure occurs mostly indoors. We therefore compared the toxic effects of classroom, outdoor, and residential PM(10). Indoor and outdoor PM(10) was collected from six schools in Munich during teaching hours and in six homes. Particles were analyzed by scanning electron microscopy and X-ray spectroscopy (EDX). Toxicity was evaluated in human primary keratinocytes, lung epithelial cells and after metabolic activation by several human cytochromes P450. We found that PM(10) concentrations during teaching hours were 5.6-times higher than outdoors (117 ± 48 μg/m(3) vs. 21 ± 15 μg/m(3), P particle number), organic (29%, probably originating from human skin), and Ca-carbonate particles (12%, probably originating from paper). Outdoor PM contained more Ca-sulfate particles (38%). Indoor PM at 6 μg/cm(2) (10 μg/ml) caused toxicity in keratinocytes and in cells expressing CYP2B6 and CYP3A4. Toxicity by CYP2B6 was abolished with the reactive oxygen species scavenger N-acetylcysteine. We concluded that outdoor PM(10) and indoor PM(10) from homes were devoid of toxicity. Indoor PM(10) was elevated, chemically different and toxicologically more active than outdoor PM(10). Whether the effects translate into a significant health risk needs to be determined. Until then, we suggest better ventilation as a sensible option. Indoor air PM(10) on an equal weight base is toxicologically more active than outdoor PM(10). In addition, indoor PM(10) concentrations are about six times higher than outdoor air. Thus, ventilation of classrooms with outdoor air will improve air quality and is likely to provide a health benefit. It is also easier than cleaning PM(10) from indoor air, which has proven to be tedious. © 2011 John Wiley & Sons A/S.

Evaluation of fine ceramics raw powders with particle size analyzers having different measuring principle and its problem

International Nuclear Information System (INIS)

Hayakawa, Osamu; Nakahira, Kenji; Tsubaki, Junichiro.

1995-01-01

Many kinds of analyzers based on various principles have been developed for measuring particle size distribution of fine ceramics powders. But the reproducibility of the results, interchangeability of the models, reliability of the ends of the measured distribution have not been investigated for each principle. In this paper, these important points for particle size analysis were clarified by measuring raw material powders of fine ceramics. (1) in the case of laser diffraction and scattering method, the reproducibility in the same model is good, however, interchangeability of the different models is not so good, especially at the ends of the distribution. Submicron powders having high refractive index show such a tendency remarkably. (2) the photo sedimentation method has some problems to be conquered, especially in measuring submicron powders having high refractive index or flaky shape particles. The reproducibility of X-ray sedimentation method is much better than that of photo sedimentation. (3) the light obscuration and electrical sensing zone methods, show good reproducibility, however, sometime bad interchangeability is affected by calibration and so on. (author)

Some Outdoor Educators' Experiences of Outdoor Education

Science.gov (United States)

Gunn, Terry

2006-01-01

The phenomenological study presented in this paper attempts to determine, from outdoor educators, what it meant for them to be teaching outdoor education in Victorian secondary schools during 2004. In 1999, Lugg and Martin surveyed Victorian secondary schools to determine the types of outdoor education programs being run, the objectives of those…

UV durable colour pigment doped SmA liquid crystal composites for outdoor trans-reflective bi-stable displays

Science.gov (United States)

Xu, H.; Davey, A. B.; Crossland, W. A.; Chu, D. P.

2012-10-01

High brightness trans-reflective bi-stable displays based on smectic A (SmA) liquid crystals (LCs) can have nearly perfect transparency in the clear state and very high reflection in the scattered state. Because the LC material in use is stable under UV radiation, this kind of displays can stand for strong day-light and therefore be ideal for outdoor applications from e-books to public signage and advertisement. However, the colour application has been limited because the traditional colourants in use are conventional dyes which are lack of UV stability and that their colours are easily photo bleached. Here we present a colour SmA display demonstrator using pigments as colourant. Mixing pigments with SmA LCs and maintain the desirable optical switching performance is not straightforward. We show here how it can be done, including how to obtain fine sized pigment nano-particles, the effects of particle size and size distribution on the display performance. Our optimized pigments/SmA compositions can be driven by a low frequency waveform (~101Hz) to a scattered state to exhibit colour while by a high frequency waveform (~103Hz) to a cleared state showing no colour. Finally, we will present its excellent UV life-time (at least <7.2 years) in comparison with that of dye composition (~2.4 years). The complex interaction of pigment nano-particles with LC molecules and the resulting effects on the LC electro-optical performances are still to be fully understood. We hope this work will not only demonstrate a new and practical approach for outdoor reflective colour displays but also provide a new material system for fundamental liquid crystal colloid research work.

NARSTO fine-particle and ozone assessments

International Nuclear Information System (INIS)

Hales, Jeremy M.

2003-01-01

The NARSTO ozone and fine-particle assessments compile and present policy-relevant scientific information. - NARSTO, a tri-national North American consortium for applied tropospheric pollution research, conducts periodic assessments of air-pollution behavior to provide an information interface between the research community and individuals working in policy analysis and air-quality management. The first of these, entitled An Assessment of Tropospheric Ozone Pollution-A North American Perspective, appeared in late 2000 and has been circulated widely throughout the United States, Canada, Mexico, Europe, and South America. The second (currently) entitled NARSTO Assessment of the Atmospheric Science on Particulate Matter, is presently in its third-draft phase and is available for general review. A fourth draft, incorporating comments from the current review stage, will be submitted in January 2002 to a tri-national review committee composed of the Canadian Royal Society, the US National Academy of Sciences, and the Mexican Red de Desarrollo e Investigacion de la Calidad del Aire en Grandes Ciudades. Finalization of the document will follow this review, which will conclude in July 2000. Publication is expected in December 2002. These two assessments contain substantial amounts of policy-relevant information, which is of interest to the research community as well as those working in policy analysis and air-quality management. This presentation provides a brief overview of features and findings of the two documents

Comparison of fine particle colemanite and boron frit in concrete for time-strength relationship

International Nuclear Information System (INIS)

Volkman, D.E.; Bussolini, P.L.

1992-01-01

This paper reports that the element boron, when added to concrete, has proved effective in shielding neutron particles by absorbing the neutron and emitting a low-energy gamma ray. The various boron additives used with concrete can severely retard the set time and strength gain. An advantage to using small particle size boron is that the smaller grain size provides better boron disbursement within the concrete matrix to absorb neutrons. However, boron additives of powder consistency are usually not used due to the greater potential of forming chemical solutions that act as a retarder in the concrete. Research has shown that the amount of boron additives in concrete can be reduced significantly if fine grain particles can be successfully incorporated into the concrete matrix. The purpose of this study is to compare strength gain characteristics of concrete mixes containing various quantities of fine grain boron additive. The boron additive colemanite, a natural mineral, is compared with two brands of manufactured aggregate, boron frit. Concrete test cylinders are molded for testing the compressive strength of the mix after 4, 7, 28, and 56 days. Tested are five different quantities of colemanite as well as five comparable amounts of boron frit for each brand of the material. The test values are compared with a control concrete specimen containing no boron additive. Results of this study can be used to optimize the cost and effectiveness of boron additives in radiation shielding concrete

The influence of fine char particles burnout on bed agglomeration during the fluidized bed combustion of a biomass fuel

Energy Technology Data Exchange (ETDEWEB)

Scala, Fabrizio; Chirone, Riccardo [Istituto di Ricerche sulla Combustione, CNR, P.le V. Tecchio, 80-80125 Naples (Italy); Salatino, Piero [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, P.le V. Tecchio, 80-80125 Naples (Italy)

2003-11-15

The combustion of biomass char in a bubbling fluidized bed is hereby addressed, with specific reference to the influence that the combustion of fine char particles may exert on ash deposition and bed agglomeration phenomena. Experiments of steady fluidized bed combustion (FBC) of powdered biomass were carried out with the aim of mimicking the postcombustion of attrited char fines generated in the fluidized bed combustion of coarse char. Experimental results showed that the char elutriation rate is much smaller than expected on the basis of the average size of the biomass powder and of the carbon loading in the combustor. Samples of bed material collected after prolonged operation of the combustor were characterized by scanning electron microscopy (SEM)-EDX analysis and revealed the formation of relatively coarse sand-ash-carbon aggregates. The phenomenology is consistent with the establishment of a char phase attached to the bed material as a consequence of adhesion of char fines onto the sand particles. Combustion under sound-assisted fluidization conditions was also tested. As expected, enhancement of fines adhesion on bed material and further reduction of the elutriation rate were observed. Experimental results are interpreted in the light of a simple model which accounts for elutriation of free fines, adhesion of free fines onto bed material and detachment of attached fines by attrition of char-sand aggregates. Combustion of both free and attached char fines is considered. The parameters of the model are assessed on the basis of the measured carbon loadings and elutriation rates. Model computations are directed to estimate the effective size and the peak temperature of char-sand aggregates. The theoretical estimates of the effective aggregate size match fairly well those observed in the experiments.

Indoor and Outdoor Exposure to Ultrafine, Fine and Microbiologically Derived Particulate Matter Related to Cardiovascular and Respiratory Effects in a Panel of Elderly Urban Citizens

Directory of Open Access Journals (Sweden)

Dorina Gabriela Karottki

2015-02-01

Full Text Available To explore associations of exposure to ambient and indoor air particulate and bio-aerosol pollutants with cardiovascular and respiratory disease markers, we utilized seven repeated measurements from 48 elderly subjects participating in a 4-week home air filtration study. Microvascular function (MVF, lung function, blood leukocyte counts, monocyte adhesion molecule expression, C-reactive protein, Clara cell protein (CC16 and surfactant protein-D (SPD were examined in relation to exposure preceding each measurement. Exposure assessment included 48-h urban background monitoring of PM10, PM2.5 and particle number concentration (PNC, weekly measurements of PM2.5 in living- and bedroom, 24-h measurements of indoor PNC three times, and bio-aerosol components in settled dust on a 2-week basis. Statistically significant inverse associations included: MVF with outdoor PNC; granulocyte counts with PM2.5; CD31 expression with dust fungi; SPD with dust endotoxin. Significant positive associations included: MVF with dust bacteria; monocyte expression of CD11 with PM2.5 in the bedroom and dust bacteria and endotoxin, CD31 expression with dust serine protease; serum CC16 with dust NAGase. Multiple comparisons demand cautious interpretation of results, which suggest that outdoor PNC have adverse effects on MVF, and outdoor and indoor PM2.5 and bio-aerosols are associated with markers of inflammation and lung cell integrity.

Parameter and model uncertainty in a life-table model for fine particles (PM2.5): a statistical modeling study.

Science.gov (United States)

Tainio, Marko; Tuomisto, Jouni T; Hänninen, Otto; Ruuskanen, Juhani; Jantunen, Matti J; Pekkanen, Juha

2007-08-23

The estimation of health impacts involves often uncertain input variables and assumptions which have to be incorporated into the model structure. These uncertainties may have significant effects on the results obtained with model, and, thus, on decision making. Fine particles (PM2.5) are believed to cause major health impacts, and, consequently, uncertainties in their health impact assessment have clear relevance to policy-making. We studied the effects of various uncertain input variables by building a life-table model for fine particles. Life-expectancy of the Helsinki metropolitan area population and the change in life-expectancy due to fine particle exposures were predicted using a life-table model. A number of parameter and model uncertainties were estimated. Sensitivity analysis for input variables was performed by calculating rank-order correlations between input and output variables. The studied model uncertainties were (i) plausibility of mortality outcomes and (ii) lag, and parameter uncertainties (iii) exposure-response coefficients for different mortality outcomes, and (iv) exposure estimates for different age groups. The monetary value of the years-of-life-lost and the relative importance of the uncertainties related to monetary valuation were predicted to compare the relative importance of the monetary valuation on the health effect uncertainties. The magnitude of the health effects costs depended mostly on discount rate, exposure-response coefficient, and plausibility of the cardiopulmonary mortality. Other mortality outcomes (lung cancer, other non-accidental and infant mortality) and lag had only minor impact on the output. The results highlight the importance of the uncertainties associated with cardiopulmonary mortality in the fine particle impact assessment when compared with other uncertainties. When estimating life-expectancy, the estimates used for cardiopulmonary exposure-response coefficient, discount rate, and plausibility require careful

Parameter and model uncertainty in a life-table model for fine particles (PM2.5: a statistical modeling study

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Jantunen Matti J

2007-08-01

Full Text Available Abstract Background The estimation of health impacts involves often uncertain input variables and assumptions which have to be incorporated into the model structure. These uncertainties may have significant effects on the results obtained with model, and, thus, on decision making. Fine particles (PM2.5 are believed to cause major health impacts, and, consequently, uncertainties in their health impact assessment have clear relevance to policy-making. We studied the effects of various uncertain input variables by building a life-table model for fine particles. Methods Life-expectancy of the Helsinki metropolitan area population and the change in life-expectancy due to fine particle exposures were predicted using a life-table model. A number of parameter and model uncertainties were estimated. Sensitivity analysis for input variables was performed by calculating rank-order correlations between input and output variables. The studied model uncertainties were (i plausibility of mortality outcomes and (ii lag, and parameter uncertainties (iii exposure-response coefficients for different mortality outcomes, and (iv exposure estimates for different age groups. The monetary value of the years-of-life-lost and the relative importance of the uncertainties related to monetary valuation were predicted to compare the relative importance of the monetary valuation on the health effect uncertainties. Results The magnitude of the health effects costs depended mostly on discount rate, exposure-response coefficient, and plausibility of the cardiopulmonary mortality. Other mortality outcomes (lung cancer, other non-accidental and infant mortality and lag had only minor impact on the output. The results highlight the importance of the uncertainties associated with cardiopulmonary mortality in the fine particle impact assessment when compared with other uncertainties. Conclusion When estimating life-expectancy, the estimates used for cardiopulmonary exposure

Determining contributions of biomass burning and other sources to fine particle contemporary carbon in the western United States

Science.gov (United States)

Holden, Amanda S.; Sullivan, Amy P.; Munchak, Leigh A.; Kreidenweis, Sonia M.; Schichtel, Bret A.; Malm, William C.; Collett, Jeffrey L., Jr.

2011-02-01

Six-day integrated fine particle samples were collected at urban and rural sampling sites using Hi-Volume samplers during winter and summer 2004-2005 as part of the IMPROVE (Interagency Monitoring of PROtected Visual Environments) Radiocarbon Study. Filter samples from six sites (Grand Canyon, Mount Rainier, Phoenix, Puget Sound, Rocky Mountain National Park, and Tonto National Monument) were analyzed for levoglucosan, a tracer for biomass combustion, and other species by High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). Contemporary carbon concentrations were available from previous carbon isotope measurements at Lawrence Livermore National Laboratory. Primary contributions of biomass burning to measured fine particle contemporary carbon were estimated for residential wood burning (winter) and wild/prescribed fires (summer). Calculated contributions ranged from below detection limit to more than 100% and were typically higher at rural sites and during winter. Mannitol, a sugar alcohol emitted by fungal spores, was analyzed and used to determine contributions of fungal spores to fine particle contemporary carbon. Contributions reached up to 13% in summer samples, with higher contributions at rural sites. Concentrations of methyltetrols, oxidation products of isoprene, were also measured by HPAEC-PAD. Secondary organic aerosol (SOA) from isoprene oxidation was estimated to contribute up to 22% of measured contemporary carbon. For each sampling site, a substantial portion of the contemporary carbon was unexplained by primary biomass combustion, fungal spores, or SOA from isoprene oxidation. This unexplained fraction likely contains contributions from other SOA sources, including oxidation products of primary smoke emissions and plant emissions other than isoprene, as well as other primary particle emissions from meat cooking, plant debris, other biological aerosol particles, bio-diesel combustion, and other sources. Loss

Identification of metals into fine particles (PM2.5) during the dry cold season in the Toluca City

International Nuclear Information System (INIS)

Martinez P, A. A.; Aldape U, F.

2008-01-01

To know the elemental content of fine particles PM 2.5 that can affect people in the Toluca City, such as metals and another, it was made a campaign collection of fine particles during dry-cold ( November 2006-March 2007). The aerosol samples were collected on Teflon filters with an equipment BGI model PQ200 mark authorized by the Environment Protection Agency (EPA), every other day with a time resolution of 24 h. The determination of the elemental composition of the samples was performed by means of the technique Particle Induced X-Ray Emission (PIXE). The results of the analysis showed consistently 13 elements S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, as, throughout the collection period. We calculated the enrich factor that separates the elements of the natural component of the anthropogenic component. The correlation matrix shows the pairs of elements that are contained in the same air mass as Vanadium and Nickel. From the results it is concluded that the sources that gave rise to these particles are the burning of fossil fuels in motor vehicles, lubricants, additives and burning tires wear of automotive vehicles, besides the products used in agricultural activities. (Author)

Health effects of exhaust particles

Energy Technology Data Exchange (ETDEWEB)

Pihlava, T.; Uuppo, M.; Niemi, S.

2013-11-01

, they can migrate far away from their source and they can even spread into the blood circulation and the brain. Transition metals on the surface of particles together with carcinogenic compounds found in the PM have been shown to cause cancer. Diesel ultra-fine particles are mainly elemental carbon, organic carbon and sulphuric acid. Sulphur still exists in diesel fuel in certain regions and if the amount of sulphur in the fuel is reduced, particles are reduced as well. Metallic compounds originate mainly from the lubrication oil, but also from the fuel and engine wear. In urban areas the amounts of particles are usually higher than in rural areas. Regulations for air quality in urban areas have been set to protect people living in the cities. Regulations are also becoming stricter in the field of internal combustion engines and particle numbers along with their mass are regulated in the EURO 6 standard. Diesel PM can be reduced by several means. Reformulating the fuel and lubrication oil directly influences PM emissions while different aftertreatment systems can be used to remove PM from the engine exhaust gases. With a well-optimized injection system, burning is more complete and PM emissions are also reduced. Exposure to particles can be decreased by avoiding busy roads where the level of particles is usually high, having a hobby that involves less exertion and decreasing exercise time. Outdoor activities should be reduced when PM concentration in the air is high. (orig.)

Explaining the spatiotemporal variation of fine particle number concentrations over Beijing and surrounding areas in an air quality model with aerosol microphysics

International Nuclear Information System (INIS)

Chen, Xueshun; Wang, Zifa; Li, Jie; Chen, Huansheng; Hu, Min; Yang, Wenyi; Wang, Zhe; Ge, Baozhu; Wang, Dawei

2017-01-01

In this study, a three-dimensional air quality model with detailed aerosol microphysics (NAQPMS + APM) was applied to simulate the fine particle number size distribution and to explain the spatiotemporal variation of fine particle number concentrations in different size ranges over Beijing and surrounding areas in the haze season (Jan 15 to Feb 13 in 2006). Comparison between observations and the simulation indicates that the model is able to reproduce the main features of the particle number size distribution. The high number concentration of total particles, up to 26600 cm −3 in observations and 39800 cm −3 in the simulation, indicates the severity of pollution in Beijing. We find that primary particles with secondary species coating and secondary particles together control the particle number size distribution. Secondary particles dominate particle number concentration in the nucleation mode. Primary and secondary particles together determine the temporal evolution and spatial pattern of particle number concentration in the Aitken mode. Primary particles dominate particle number concentration in the accumulation mode. Over Beijing and surrounding areas, secondary particles contribute at least 80% of particle number concentration in the nucleation mode but only 10–20% in the accumulation mode. Nucleation mode particles and accumulation mode particles are anti-phased with each other. Nucleation or primary emissions alone could not explain the formation of the particle number size distribution in Beijing. Nucleation has larger effects on ultrafine particles while primary particles emissions are efficient in producing large particles in the accumulation mode. Reduction in primary particle emissions does not always lead to a decrease in the number concentration of ultrafine particles. Measures to reduce fine particle pollution in terms of particle number concentration may be different from those addressing particle mass concentration. - Highlights: �

Fine-particle pH for Beijing winter haze as inferred from different thermodynamic equilibrium models

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S. Song

2018-05-01

Full Text Available pH is an important property of aerosol particles but is difficult to measure directly. Several studies have estimated the pH values for fine particles in northern China winter haze using thermodynamic models (i.e., E-AIM and ISORROPIA and ambient measurements. The reported pH values differ widely, ranging from close to 0 (highly acidic to as high as 7 (neutral. In order to understand the reason for this discrepancy, we calculated pH values using these models with different assumptions with regard to model inputs and particle phase states. We find that the large discrepancy is due primarily to differences in the model assumptions adopted in previous studies. Calculations using only aerosol-phase composition as inputs (i.e., reverse mode are sensitive to the measurement errors of ionic species, and inferred pH values exhibit a bimodal distribution, with peaks between −2 and 2 and between 7 and 10, depending on whether anions or cations are in excess. Calculations using total (gas plus aerosol phase measurements as inputs (i.e., forward mode are affected much less by these measurement errors. In future studies, the reverse mode should be avoided whereas the forward mode should be used. Forward-mode calculations in this and previous studies collectively indicate a moderately acidic condition (pH from about 4 to about 5 for fine particles in northern China winter haze, indicating further that ammonia plays an important role in determining this property. The assumed particle phase state, either stable (solid plus liquid or metastable (only liquid, does not significantly impact pH predictions. The unrealistic pH values of about 7 in a few previous studies (using the standard ISORROPIA model and stable state assumption resulted from coding errors in the model, which have been identified and fixed in this study.

Chemical compositions of subway particles in Seoul, Korea determined by a quantitative single particle analysis.

Science.gov (United States)

Kang, Sunni; Hwang, HeeJin; Park, YooMyung; Kim, HyeKyoung; Ro, Chul-Un

2008-12-15

A novel single particle analytical technique, low-Z particle electron probe X-ray microanalysis, was applied to characterize seasonal subway samples collected at a subway station in Seoul, Korea. For all 8 samples collected twice in each season, 4 major types of subway particles, based on their chemical compositions, are significantly encountered: Fe-containing; soil-derived; carbonaceous; and secondary nitrate and/or sulfate particles. Fe-containing particles are generated indoors from wear processes at rail-wheel-brake interfaces while the others may be introduced mostly from the outdoor urban atmosphere. Fe-containing particles are the most frequently encountered with relative abundances in the range of 61-79%. In this study, it is shown that Fe-containing subway particles almost always exist either as partially or fully oxidized forms in underground subway microenvironments. Their relative abundances of Fe-containing particles increase as particle sizes decrease. Relative abundances of Fe-containing particles are higher in morning samples than in afternoon samples because of heavier train traffic in the morning. In the summertime samples, Fe-containing particles are the most abundantly encountered, whereas soil-derived and nitrate/sulfate particles are the least encountered, indicating the air-exchange between indoor and outdoor environments is limited in the summer, owing to the air-conditioning in the subway system. In our work, it was observed that the relative abundances of the particles of outdoor origin vary somewhat among seasonal samples to a lesser degree, reflecting that indoor emission sources predominate.

Study on fine particles influence on sodium sulfite and oxygen gas-liquid reaction

Energy Technology Data Exchange (ETDEWEB)

Tao, Shuchang; Zhao, Bo; Wang, Shujuan; Zhuo, Yuqun; Chen, Changhe [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering; Ministry of Education, Beijing (China). Key Lab. for Thermal Science and Power Engineering

2013-07-01

Wet limestone scrubbing is the most common flue gas desulfurization process for control of sulfur dioxide emissions from the combustion of fossil fuels, and forced oxidation is a key part of the reaction. During the reaction which controlled by gas-liquid mass transfer, the fine particles' characteristic, size, solid loading and temperature has a great influence on gas-liquid mass transfer. In the present work is to explain how these factors influence the reaction between Na{sub 2}SO{sub 3} and O{sub 2} and find the best react conditions through experiment. The oxidation rate was experimentally studied by contacting pure oxygen with a sodium sulfite solution with active carbon particle in a stirred tank, and the system pressure drop was record by the pressure sensor. At the beginning the pressure is about 215 kPa and Na{sub 2}SO{sub 3} is about 0.5mol/L. The temperature is 40, 50, 60, 70, 80 C. Compare the results of no particles included, we can conclude that high temperature, proper loadings and smaller particles resulting in higher mass transfer coefficients k{sub L}.

Significance of Fines in Hot Mix Asphalt Synthesis

Directory of Open Access Journals (Sweden)

Kalaitzaki Elvira

2017-07-01

Full Text Available According to their size, aggregates are classified in coarse grained, fine grained, and fines. The determination of fines content in aggregate materials is very simple and is performed through the aggregate washing during the sieving procedure to define the gradation curve. The very fine material consists of grains having a size lower than 63 μm. The presence of fines directly influences the composition and performance of concrete and asphalt mixtures (e.g. asphalt content, elasticity, fracture. The strength and load carrying capacity of hot mix asphalt (HMA results from the aggregate framework created through particle-particle contact and interlock. Fines or mineral filler have a role in HMA. The coarse aggregate framework is filled by the sand-sized material and finally by the mineral filler. At some point, the smallest particles lose contact becoming suspended in the binder not having the particle-particle contact that is created by the larger particles. The overall effect of mineral filler in hot mix asphalt specimens has been investigated through a series of laboratory tests. It is clear that a behaviour influenced by the adherence of fines to asphalt film has been developed. The optimum bitumen content requirement in case of stone filler is almost the same as that for fly ash. It has been found that the percentage of fly ash filler is crucial if it exceeds approximately a value of 4%.

Indoor/outdoor elemental concentration relationships at a nursery school

International Nuclear Information System (INIS)

Lannefors, H.; Hansson, H.C.

1981-01-01

Indoor and outdoor concentrations of lead and bromine have been measured at a nursery school, using streaker samplers with 2.4 h resolution. The observed variations in concentration were well-correlated with traffic intensity variations. In addition to their closely related time-variation curves, the bromine to lead ratios pointed to the emissions from leaded gasoline-powered vehicles as the main source of these elements both in and outdoors. Time-variation patterns on weekdays and during weekends indicated that the lead and bromine containing particles entered the nursery school mainly by leaking. Only a minor fraction seemed to be brought in and resuspended by the staff and children. The indoor concentrations of the elements studied were about 5 times lower than the outdoor levels thus considerably reducing the indoor exposure. (orig.)

Outdoor recreation-related outdoor education: scope of the research (1995-2010) 2

OpenAIRE

Lynch, Philippa

2012-01-01

Article made available with the permission of the New Zealand Journal of Outdoor Education. This is part two of an article on the scope of the New Zealand outdoor recreation-related outdoor education research published from January 1995 to June 2010. It draws on the literature covered the 2010 Sport and Recreation New Zealand-funded Outdoor Recreation Research Stocktake, which included outdoor education material. This part covers resources for outdoor recreation-related outdoor education, ...

INDOOR-OUTDOOR AEROSOL CONCENTRATIONS IN TWO PORTUGUESE CITIES AND THE GLOBAL WARMING SCENARIO

Energy Technology Data Exchange (ETDEWEB)

Antonio F. Miguel; A. Heitor Reis [Department of Physics, University of Evora (Portugal); Marta Melgao [Geophysics Centre of Evora (Portugal)

2008-09-30

Aerosols play a major role both in climate change and in air quality. They affect climate through interfering with radiative transfer and hence the atmospheric temperature, and also the air quality. Many epidemiological studies have confirmed that a relation exists between elevated aerosol particle concentration and adverse human health effects. Aerosol particle number and size distributions were measured both indoors and outdoors in the urban areas of Evora and Lisbon. We investigated the indoor-to-outdoor relationship of aerosol particles and the aerosol size distributions. The impact of the occurrence of a residential fire in the aerosol size distribution is also analyzed. Finally, we speculate of how global increase in temperature can affect concentration of aerosols in the atmosphere, via increased boundary layer convection.

Chemical characteristics of fine particles emitted from different gas cooking methods

Science.gov (United States)

See, Siao Wei; Balasubramanian, Rajasekhar

Gas cooking is an important indoor source of fine particles (PM 2.5). The chemical characteristics of PM 2.5 emitted from different cooking methods, namely, steaming, boiling, stir-frying, pan-frying and deep-frying were investigated in a domestic kitchen. Controlled experiments were conducted to measure the mass concentration of PM 2.5 and its chemical constituents (elemental carbon (EC), organic carbon (OC), polycyclic aromatic hydrocarbons (PAHs), metals and ions) arising from these five cooking methods. To investigate the difference in particle properties of different cooking emissions, the amount and type of food, and the heat setting on the gas stove were kept constant during the entire course of the experiments. Results showed that deep-frying gave rise to the largest amount of PM 2.5 and most chemical components, followed by pan-frying, stir-frying, boiling, and steaming. Oil-based cooking methods released more organic pollutants (OC, PAHs, and organic ions) and metals, while water-based cooking methods accounted for more water-soluble (WS) ions. Their source profiles are also presented and discussed.

Growth and sedimentation of fine particles produced in aqueous solutions of palladium sulfate and palladium sulfate-silver sulfate induced by gamma-ray irradiation

International Nuclear Information System (INIS)

Hatada, Motoyoshi; Jonah, C.D.

1994-10-01

It is known that palladium and palladium-silver fine particles were formed from deaerated aqueous solutions of palladium sulfate and palladium sulfate-silver sulfate induced by gamma-ray irradiation. Changes in particle size and with amount of particles in the solution with time during and after irradiation were studied using dynamic light scattering technique and UV spectrophotometer. The particles formed from palladium sulfate solution are found to be water-filled bulky particles of diameter of 200 nm, which grow by mutual coagulation even after irradiation was terminated. Average density depends on concentration of palladium ion in the solution and dose, and the lowest density was about 2 g/cm 3 for particles of 200 nm obtained from 0.06 mM solution by 2.4 kGy irradiation. The average density of the particles obtained from palladium sulfate-silver sulfate solutions was smaller than those obtained for the corresponding palladium sulfate solutions. Supersonic agitation destroyed coagulated precipitates to form fine particles, but did not form clusters of a few atoms. (author)

Agglomeration of coal fines for premium fuel application

International Nuclear Information System (INIS)

Atalay, A.; Zaman, M.D.

1992-01-01

This paper reports on fine coal in liquid suspension, which can be agglomerated in a number of ways. One of the oldest procedures involves the addition of electrolyte to the suspension to cause a reduction in the zeta potential and allow colliding particles to agglomerate. A second method involves the use of polymeric flocculants to bridge between particles. Both of these technologies are being used in the wastewater treatment plants for removal of fine waste particles from contaminated water. A third method involves the addition of a second immiscible liquid preferentially to wet the particles and cause adhesion by capillary interfacial forces. While the bonding forces in the first two methods are small and result in rather weak and voluminous agglomerates, the third method is postulated to produce more dense and much stronger agglomerates. In the case of fine coals, the carbonaceous constituents can be agglomerated and recovered from the aqueous suspension with many different coagulants. Inorganic or ash-forming constituents are also agglomerated along with the fine coal particles. As the froth floatation, agglomeration using coal and colloidal dust to effect a separation. Froth floatation, however, becomes less effective where extremely fine particles of cal must be treated or if there is considerable clay-size particle present. In contrast, there appears to be virtually no lower limit on the particle size suitable for agglomeration uses

Short-term exposure to fine and coarse particles and mortality: A multicity time-series study in East Asia

International Nuclear Information System (INIS)

Lee, Hyewon; Honda, Yasushi; Hashizume, Masahiro; Guo, Yue Leon; Wu, Chang-Fu; Kan, Haidong; Jung, Kweon; Lim, Youn-Hee; Yi, Seungmuk; Kim, Ho

2015-01-01

Few studies on size-specific health effects of particulate matter have been conducted in Asia. We examined the association between both fine and coarse particles (PM_2_._5 and PM_1_0_−_2_._5) and mortality across 11 East Asian cities from 4 countries (Korea, Japan, Taiwan, and China). We performed a two-stage analysis: we generated city-specific estimates using a time-series analysis with a generalized additive model (Quasi-Poisson distribution), and estimated the overall effects by conducting a meta-analysis. Each 10−μg/m"3 increase in PM_2_._5 (lag01) was associated with an increase of 0.38% (95% confidence interval = 0.21%–0.55%) in all causes mortality, 0.96% (0.46%–1.46%) in cardiovascular mortality, and 1% (0.23%–1.78%) in respiratory mortality. Each 10−μg/m"3 increase in PM_1_0_−_2_._5 (lag01) was associated with cardiovascular mortality (0.69%, [0.05%–1.33%]), although this association attenuated after controlling for other pollutants, especially PM_2_._5. Increased mortality was associated with increasing PM_2_._5 and PM_1_0_−_2_._5 concentrations over 11 East Asian cities. - Highlights: • Few studies on size-specific health effects of PM have been conducted in East Asia. • We estimated size-specific PM effects on mortality over 11 East Asian cities. • Both fine and coarse particles were associated with mortality in East Asian cites. • Effect estimates for fine particles were higher than those for coarse particles. - Short-term exposure to PM_2_._5 and PM_1_0_−_2_._5 was associated with an increased risk of mortality in East Asian cities, and PM_2_._5 effect estimates were higher than PM_1_0_−_2_._5.

SWeRF--A method for estimating the relevant fine particle fraction in bulk materials for classification and labelling purposes.

Science.gov (United States)

Pensis, Ingeborg; Luetzenkirchen, Frank; Friede, Bernd

2014-05-01

In accordance with the European regulation for classification, labelling and packaging of substances and mixtures (CLP) as well as the criteria as set out in the Globally Harmonized System (GHS), fine fraction of crystalline silica (CS) has been classified as a specific target organ toxicity, the specific organ in this case being the lung. Generic cut-off values for products containing a fine fraction of CS trigger the need for a method for the quantification of the fine fraction of CS in bulk materials. This article describes the so-called SWeRF method, the size-weighted relevant fine fraction. The SWeRF method combines the particle size distribution of a powder with probability factors from the EN 481 standard and allows the relevant fine fraction of a material to be calculated. The SWeRF method has been validated with a number of industrial minerals. This will enable manufacturers and blenders to apply the CLP and GHS criteria for the classification of mineral products containing RCS a fine fraction of CS.

Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

Directory of Open Access Journals (Sweden)

Nanbu H.

2010-06-01

Full Text Available In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.

Dispersibility of lactose fines as compared to API in dry powders for inhalation.

Science.gov (United States)

Thalberg, Kyrre; Åslund, Simon; Skogevall, Marcus; Andersson, Patrik

2016-05-17

This work investigates the dispersion performance of fine lactose particles as function of processing time, and compares it to the API, using Beclomethasone Dipropionate (BDP) as model API. The total load of fine particles is kept constant in the formulations while the proportions of API and lactose fines are varied. Fine particle assessment demonstrates that the lactose fines have higher dispersibility than the API. For standard formulations, processing time has a limited effect on the Fine Particle Fraction (FPF). For formulations containing magnesium stearate (MgSt), FPF of BDP is heavily influenced by processing time, with an initial increase, followed by a decrease at longer mixing times. An equation modeling the observed behavior is presented. Surprisingly, the dispersibility of the lactose fines present in the same formulation remains unaffected by mixing time. Magnesium analysis demonstrates that MgSt is transferred to the fine particles during the mixing process, thus lubrication both BDP and lactose fines, which leads to an increased FPF. Dry particle sizing of the formulations reveals a loss of fine particles at longer mixing times. Incorporation of fine particles into the carrier surfaces is believed to be behind this, and is hence a mechanism of importance as regards the dispersion performance of dry powders for inhalation. Copyright © 2016 Elsevier B.V. All rights reserved.

Indoor particle dynamics in a school office: determination of particle concentrations, deposition rates and penetration factors under naturally ventilated conditions.

Science.gov (United States)

Cong, X C; Zhao, J J; Jing, Z; Wang, Q G; Ni, P F

2018-05-09

Recently, the problem of indoor particulate matter pollution has received much attention. An increasing number of epidemiological studies show that the concentration of atmospheric particulate matter has a significant effect on human health, even at very low concentrations. Most of these investigations have relied upon outdoor particle concentrations as surrogates of human exposures. However, considering that the concentration distribution of the indoor particulate matter is largely dependent on the extent to which these particles penetrate the building and on the degree of suspension in the indoor air, human exposures to particles of outdoor origin may not be equal to outdoor particle concentration levels. Therefore, it is critical to understand the relationship between the particle concentrations found outdoors and those found in indoor micro-environments. In this study, experiments were conducted using a naturally ventilated office located in Qingdao, China. The indoor and outdoor particle concentrations were measured at the same time using an optical counter with four size ranges. The particle size distribution ranged from 0.3 to 2.5 μm, and the experimental period was from April to September, 2016. Based on the experimental data, the dynamic and mass balance model based on time was used to estimate the penetration rate and deposition rate at air exchange rates of 0.03-0.25 h -1 . The values of the penetration rate and deposition velocity of indoor particles were determined to range from 0.45 to 0.82 h -1 and 1.71 to 2.82 m/h, respectively. In addition, the particulate pollution exposure in the indoor environment was analyzed to estimate the exposure hazard from indoor particulate matter pollution, which is important for human exposure to particles and associated health effects. The conclusions from this study can serve to provide a better understanding the dynamics and behaviors of airborne particle entering into buildings. And they will also highlight

A twelve month study of PM2.5 and PM10 fine particle aerosol composition in the Sydney region using ion beam analysis techniques. Appendix 2

International Nuclear Information System (INIS)

Cohen, David D.; Bailey, G.M.; Kondepudi, Ramesh

1995-01-01

The accelerator based ion beam (IBA) analysis techniques of PIXE, PIGME, PESA, and RBS have been used to characterise fine particles at selected sites in the Sydney region. The four techniques operating simultaneously provide elemental concentrations on 24 chemical species, including H, Q N, 0, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Cu, Ni, Zn, Br and Pb. The total mass and the elemental carbon by laser integrated plate techniques were also measured. A stacked filter system, built by the University of Gent, Belgium and supplied by the IAEA was used to provide fine particle data on PM2.5 and PM10 particles. While a cyclone sampler, built at ANSTO, Lucas Heights, was used to provide data on PM2.5 particles only. The two different types of units were operated along side each other for the whole of 1994 and the results compared. The use of the multi-elemental IBA techniques also allowed for some fine particle source fingerprinting to be performed. (author)

Effect of shot peening using ultra-fine particles on fatigue properties of 5056 aluminum alloy under rotating bending

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, Shoichi, E-mail: kikuchi@mech.kobe-u.ac.jp [Department of Mechanical Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe-shi, Hyogo 657-8501 (Japan); Nakamura, Yuki [Department of Mechanical Engineering, National Institute of Technology, Toyota College, 2-1 Eisei-cho, Toyota-shi, Aichi 471-8525 (Japan); Nambu, Koichiro [Department of Mechanical Engineering, National Institute of Technology, Suzuka College, Shiroko-cho, Suzuka-shi, Mie 510-0294 (Japan); Ando, Masafumi [Innovation Team, IKK SHOT Co. Ltd., 412-4, Nunowari, Minami-Shibata-machi, Tokai-shi, Aichi 476-0001 (Japan)

2016-01-15

Shot peening using particles 10 μm in diameter (ultra-fine particle peening: Ultra-FPP) was introduced to improve the fatigue properties of 5056 aluminum alloy. The surface microstructures of the Ultra-FPP treated specimens were characterized using a micro-Vickers hardness tester, scanning electron microscopy (SEM), X-ray diffraction (XRD), non-contact scanning white light interferometry, and electron backscatter diffraction (EBSD). The Ultra-FPP treated specimen had higher hardness than the conventional FPP treated specimen with a short nozzle distance due to the high velocity of the ultra-fine particles. Furthermore, the surface hardness of the Ultra-FPP treated specimen tended to increase as the peening time decreased. Fatigue tests were performed in air at room temperature using a cantilever-type rotating bending fatigue testing machine. It was found that the fatigue life of the Ultra-FPP treated specimen tended to increase with decreasing peening time. Mainly, the Ultra-FPP improved the fatigue properties of 5056 aluminum alloy in the very high cycle regime of more than 10{sup 7} cycles compared with the un-peened specimens. This is because the release of the compressive residual stress is small during fatigue tests at low stress amplitudes.

Personal exposure versus monitoring station data for respirable particles

Energy Technology Data Exchange (ETDEWEB)

Sega, K; Fugas, M

1982-01-01

Personal exposure to respirable particles of 12 subjects working at the same location, but living in various parts of Zagreb, was monitored for 7 consecutive days and compared with simultaneously obtained data from the outdoor network station nearest to subject's home. Although personal exposure is related to the outdoor pollution, other sources play a considerable role. Indoor exposure takes, on the average, more than 80% of the total time. The ratio between average personal exposure and respirable particle levels in the outdoor air decreases with the increased outdoor concentration (r = -0.93), indicating that this relationship might serve as a basis for a rough estimate of possible personal exposure.

Indoor and outdoor particulate matter in primary school classrooms with fan-assisted natural ventilation in Singapore.

Science.gov (United States)

Chen, Ailu; Gall, Elliott T; Chang, Victor W C

2016-09-01

We conducted multiday continuous monitoring of indoor and outdoor particulate matter (PM) in classrooms with fan-assisted natural ventilation (NV) at five primary schools in Singapore. We monitored size-resolved number concentration of PM with diameter 0.3-10 μm at all schools and alveolar deposited surface area concentrations of PM with diameter 0.01-1.0 μm (SA0.01-1.0) at two schools. Results show that, during the monitoring period, schools closer to expressways and in the downtown area had 2-3 times higher outdoor PM0.3-1.0 number concentrations than schools located in suburban areas. Average indoor SA0.01-1.0 was 115-118 μm(2) cm(-3) during periods of occupancy and 72-87 μm(2) cm(-3) during unoccupied periods. There were close indoor and outdoor correlations for fine PM during both occupied and unoccupied periods (Pearson's r = 0.84-1.0) while the correlations for coarse PM were weak during the occupied periods (r = 0.13-0.74). Across all the schools, the size-resolved indoor/outdoor PM ratios (I/O ratios) were 0.81 to 1.58 and 0.61 to 0.95 during occupied and unoccupied periods, respectively, and average infiltration factors were 0.64 to 0.94. Average PM net emission rates, calculated during periods of occupancy in the classrooms, were lower than or in the lower range of emission rates reported in the literature. This study also reveals that indoor fine and submicron PM predominantly come from outdoor sources, while indoor sources associated with occupancy may be important for coarse PM even when the classrooms have high air exchange rates.

Toxic effects of indoor and outdoor airborne particles relevant to carcinogenesis

NARCIS (Netherlands)

Heussen, G.A.H.

1993-01-01

The mutagenicity of indoor and outdoor airborne particulate matter (APM) has been demonstrated by previous in vitro studies (Alink et al., 1983; Van Houdt et al., 1984, 1986, 1987). The aim of the present thesis was to contribute to a better understanding of the mode of action of AIM in the

Associations between fine particle, coarse particle, black carbon and hospital visits in a Chinese city.

Science.gov (United States)

Wang, Xi; Chen, Renjie; Meng, Xia; Geng, Fuhai; Wang, Cuicui; Kan, Haidong

2013-08-01

China is one of the countries with the highest ambient particle levels in the world; however, there have been no epidemiologic studies examining the effects of fine particle (PM2.5), coarse particle (PM10-2.5) and black carbon (BC) simultaneously on morbidity outcomes. In this study, we conducted a time-series analysis to evaluate the acute effects of PM2.5, PM10-2.5, and BC on daily hospital visits in Shanghai, China. During our study period, the mean daily concentrations of PM2.5, PM10-2.5 and BC were 53.9 μg/m(3), 38.4 μg/m(3) and 3.9 μg/m(3), respectively. We found significant associations of PM2.5, PM 10-2.5, and BC with daily hospital visits. An inter-quartile range increase of the average concentrations of the current and previous days in PM2.5, PM10-2.5 and BC was associated with a 1.88% (95% CI: 0.69% to 3.06%), a 1.30% (95% CI: 0.25% to 2.34%) and a 1.33% (95% CI: 0.34% to 2.32%) increase in emergency-room visits, respectively. For outpatient visits, the corresponding estimated changes were -2.44% (95% CI: -6.62% to 1.74%), 1.09% (95% CI: -2.72% to 4.90%) and 3.34% (95% CI: 0.10% to 6.57%) respectively. The effects of BC were more robust than the effects of PM2.5 and PM10-2.5 in two-pollutant models. To our knowledge, this is the first study in China, or even in Asian developing countries, to report the effect of PM2.5, PM10-2.5, and BC simultaneously on morbidity. Our findings also suggest that BC could serve as a valuable air quality indicator that reflects the health risks of airborne particles. Copyright © 2013 Elsevier B.V. All rights reserved.

Outdoor recreation-related outdoor education: scope of the research (1995-2010) I

OpenAIRE

Lynch, Philippa

2012-01-01

Article made available with the permission of the New Zealand Journal of Outdoor Education. This article reports on the scope of the New Zealand outdoor recreationrelated outdoor education research literature published from January 1995 to June 2010. It draws on the literature covered by the 2010 Sport and Recreation New Zealand-funded Outdoor Recreation Research Stocktake, which included outdoor education material. This article is divided into two parts, both published in this issue of th...

Outdoor air pollution, preterm birth, and low birth weight: analysis of the world health organization global survey on maternal and perinatal health.

Science.gov (United States)

Fleischer, Nancy L; Merialdi, Mario; van Donkelaar, Aaron; Vadillo-Ortega, Felipe; Martin, Randall V; Betran, Ana Pilar; Souza, João Paulo

2014-04-01

Inhaling fine particles (particulate matter with diameter ≤ 2.5 μm; PM2.5) can induce oxidative stress and inflammation, and may contribute to onset of preterm labor and other adverse perinatal outcomes. We examined whether outdoor PM2.5 was associated with adverse birth outcomes among 22 countries in the World Health Organization Global Survey on Maternal and Perinatal Health from 2004 through 2008. Long-term average (2001-2006) estimates of outdoor PM2.5 were assigned to 50-km-radius circular buffers around each health clinic where births occurred. We used generalized estimating equations to determine associations between clinic-level PM2.5 levels and preterm birth and low birth weight at the individual level, adjusting for seasonality and potential confounders at individual, clinic, and country levels. Country-specific associations were also investigated. Across all countries, adjusting for seasonality, PM2.5 was not associated with preterm birth, but was associated with low birth weight [odds ratio (OR) = 1.22; 95% CI: 1.07, 1.39 for fourth quartile of PM2.5 (> 20.2 μg/m3) compared with the first quartile (levels of air pollution may be of concern for both outcomes.

Picobubble enhanced fine coal flotation

Energy Technology Data Exchange (ETDEWEB)

Tao, Y.J.; Liu, J.T.; Yu, S.; Tao, D. [University of Kentucky, Lexington, KY (United States). Dept. of Mining Engineering

2006-07-01

Froth flotation is widely used in the coal industry to clean -28 mesh fine coal. A successful recovery of particles by flotation depends on efficient particle-bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range beyond which the flotation efficiency drops drastically. It is now known that the low flotation recovery of particles in the finest size fractions is mainly due to a low probability of bubble-particle collision while the main reason for poor coarse particle flotation recovery is the high probability of detachment. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles in a wide range of size by increasing the probability of collision and attachment and reducing the probability of detachment. A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. They are characterized by a size distribution that is mostly below 1 {mu}m and adhere preferentially to the hydrophobic surfaces. The presence of picobubbles increases the probability of collision and attachment and decreases the probability of detachment, thus enhancing flotation recovery. Experimental results with the Coalberg seam coal in West Virginia, U.S.A. have shown that the use of picobubbles in a 2 in. column flotation increased fine coal recovery by 10-30%, depending on the feed rate, collector dosage, and other flotation conditions. Picobubbles also acted as a secondary collector and reduced the collector dosage by one third to one half.

Logarithmic contributions in the particle-mass ratio to the fine shift of S energy levels of hydrogen-like atoms in the fifth order in the fine-structure constant

International Nuclear Information System (INIS)

Boikova, N.A.; Kleshchevskaya, S.V.; Tyukhtyaev, Yu.N.; Faustov, R.N.

2004-01-01

A high-precision investigation of a logarithmic contribution in the particle-mass ratio to the fine shift of the S energy levels of hydrogen-like atoms from the exchange of a Coulomb photon is performed. It is shown that diagrams describing the exchange of one transverse photon and two Coulomb photons do not make such contributions

Personal exposure to ultrafine particles.

Science.gov (United States)

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).

Physical properties and structure of fine core-shell particles used as packing materials for chromatography Relationships between particle characteristics and column performance.

Science.gov (United States)

Gritti, Fabrice; Leonardis, Irene; Abia, Jude; Guiochon, Georges

2010-06-11

The recent development of new brands of packing materials made of fine porous-shell particles, e.g., Halo and Kinetex, has brought great improvements in potential column efficiency, demanding considerable progress in the design of chromatographic instruments. Columns packed with Halo and Kinetex particles provide minimum values of their reduced plate heights of nearly 1.5 and 1.2, respectively. These packing materials have physical properties that set them apart from conventional porous particles. The kinetic performance of 4.6mm I.D. columns packed with these two new materials is analyzed based on the results of a series of nine independent and complementary experiments: low-temperature nitrogen adsorption (LTNA), scanning electron microscopy (SEM), inverse size-exclusion chromatography (ISEC), Coulter counter particle size distributions, pycnometry, height equivalent to a theoretical plate (HETP), peak parking method (PP), total pore blocking method (TPB), and local electrochemical detection across the column exit section (LED). The results of this work establish links between the physical properties of these superficially porous particles and the excellent kinetic performance of columns packed with them. It clarifies the fundamental origin of the difference in the chromatographic performances of the Halo and the Kinetex columns. Copyright 2010 Elsevier B.V. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

Azarmi, Farhad; Kumar, Prashant, E-mail: p.kumar@surrey.ac.uk, E-mail: prashant.kumar@cantab.net; Mulheron, Mike [University of Surrey, Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences (United Kingdom); Colaux, Julien L.; Jeynes, Chris [University of Surrey, Faculty of Engineering and Physical Sciences, Ion Beam Centre (United Kingdom); Adhami, Siavash; Watts, John F. [University of Surrey, The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences (United Kingdom)

2015-08-15

Understanding of the emissions of coarse (PM{sub 10} ≤10 μm), fine (PM{sub 2.5} ≤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.

Atmospheric natural radioactivity outdoors

International Nuclear Information System (INIS)

Renoux, A.

1985-01-01

Following a short account of natural atmospheric radioactivity, radon concentrations are given as well as their variations with time obtained by means of a original apparatus developped in Brest. The radioactive equilibrium of radon and its daughters is then considered, many experiments demonstrating that equilibrium is seldom reached even for 218 Po (RaA). Finally, some characteristics of natural radioactive aerosols are studied: charge, particle size distribution (demonstrating they are fine aerosols since only 30 per cent are made of particles with radii exceeding 0,1 μm) [fr

Fear of moving outdoors and development of outdoor walking difficulty in older people

DEFF Research Database (Denmark)

Rantakokko, Merja; Mänty, Minna; Iwarsson, Susanne

2009-01-01

To study which individual characteristics and environmental factors correlate with fear of moving outdoors and whether fear of moving outdoors predicts development of mobility limitation.......To study which individual characteristics and environmental factors correlate with fear of moving outdoors and whether fear of moving outdoors predicts development of mobility limitation....

Coarse and fine particles but nout ultrafine particles in urban air trigger hospital admission for asthma in children

DEFF Research Database (Denmark)

Iskander, A.; Andersen, Z.J.; Bønnelykke, K.

2012-01-01

.AimTo study whether short-term exposure to air pollution is associated with hospital admissions for asthma in children. It is hypothesised that (1) the association between asthma admissions and air pollution is stronger with UFPs than with coarse (PM(10)) and fine (PM(2.5)) particles, nitrogen oxides (NO...... association was found between hospital admissions for asthma in children aged 0-18 years and NO(x) (OR 1.11; 95% CI 1.05 to 1.17), NO(2) (1.10; 95% CI 1.04 to 1.16), PM(10) (1.07; 95% CI 1.03 to 1.12) and PM(2.5) (1.09; 95% CI 1.04 to 1.13); there was no association with UFPs. The association was stronger...

Outdoor thermal comfort.

Science.gov (United States)

Nikolopoulou, Marialena

2011-06-01

A review of the various approaches in understanding outdoor thermal comfort is presented. The emphasis on field surveys from around the world, particularly across Europe, enables us to understand thermal perception and evaluate outdoor thermal comfort conditions. The consistent low correlations between objective microclimatic variables, subjective thermal sensation and comfort outdoors, internationally, suggest that thermophysiology alone does not adequate describe these relationships. Focusing on the concept of adaptation, it tries to explain how this influences outdoor comfort, enabling us to inhabit and get satisfaction from outdoor spaces throughout the year. Beyond acclimatization and behavioral adaptation, through adjustments in clothing and changes to the metabolic heat, psychological adaptation plays a critical role to ensure thermal comfort and satisfaction with the outdoor environment. Such parameters include recent experiences and expectations; personal choice and perceived control, more important than whether that control is actually exercised; and the need for positive environmental stimulation suggesting that thermal neutrality is not a pre-requisite for thermal comfort. Ultimately, enhancing environmental diversity can influence thermal perception and experience of open spaces.

FREE AND COMBINED AMINO COMPOUNDS IN ATMOSPHERIC FINE PARTICLES (PM2.5) AND FOG WATERS FROM NORTHERN CALIFORNIA. (R825433)

Science.gov (United States)

Atmospheric fine particles (PM2.5) collected during August 1997–July 1998 and wintertime fog waters collected during 1997–1999 at Davis, California were analyzed for free and combined amino compounds. In both PM2.5 and fog waters, the averag...

Ultrafine and fine particle formation in a naturally ventilated office as a result of reactions between ozone and scented products

DEFF Research Database (Denmark)

Toftum, Jørn; Dijken, F. v.

2003-01-01

Ultrafine and fine particle formation as a result of chemical reactions between ozone and four different air fresheners and a typical lemon-scented domestic cleaner was studied in a fully furnished, naturally ventilated office. The study showed that under conditions representative of those...

Use of Unprocessed Coal Bottom Ash as Partial Fine Aggregate ...

African Journals Online (AJOL)

2012r

transportation applications such as structural fill, road base material, and as snow ... normal fine particles resulting in weak porous paste, modulus of elasticity is ..... with the porous structure and high absorptivity of fine particles of bottom ash.

Comparison of fine particle measurements from a direct-reading instrument and a gravimetric sampling method.

Science.gov (United States)

Kim, Jee Young; Magari, Shannon R; Herrick, Robert F; Smith, Thomas J; Christiani, David C

2004-11-01

Particulate air pollution, specifically the fine particle fraction (PM2.5), has been associated with increased cardiopulmonary morbidity and mortality in general population studies. Occupational exposure to fine particulate matter can exceed ambient levels by a large factor. Due to increased interest in the health effects of particulate matter, many particle sampling methods have been developed In this study, two such measurement methods were used simultaneously and compared. PM2.5 was sampled using a filter-based gravimetric sampling method and a direct-reading instrument, the TSI Inc. model 8520 DUSTTRAK aerosol monitor. Both sampling methods were used to determine the PM2.5 exposure in a group of boilermakers exposed to welding fumes and residual fuel oil ash. The geometric mean PM2.5 concentration was 0.30 mg/m3 (GSD 3.25) and 0.31 mg/m3 (GSD 2.90)from the DUSTTRAK and gravimetric method, respectively. The Spearman rank correlation coefficient for the gravimetric and DUSTTRAK PM2.5 concentrations was 0.68. Linear regression models indicated that log, DUSTTRAK PM2.5 concentrations significantly predicted loge gravimetric PM2.5 concentrations (p gravimetric PM2.5 concentrations was found to be modified by surrogate measures for seasonal variation and type of aerosol. PM2.5 measurements from the DUSTTRAK are well correlated and highly predictive of measurements from the gravimetric sampling method for the aerosols in these work environments. However, results from this study suggest that aerosol particle characteristics may affect the relationship between the gravimetric and DUSTTRAK PM2.5 measurements. Recalibration of the DUSTTRAK for the specific aerosol, as recommended by the manufacturer, may be necessary to produce valid measures of airborne particulate matter.

Information and communication technology solutions for outdoor navigation in dementia.

Science.gov (United States)

Teipel, Stefan; Babiloni, Claudio; Hoey, Jesse; Kaye, Jeffrey; Kirste, Thomas; Burmeister, Oliver K

2016-06-01

Information and communication technology (ICT) is potentially mature enough to empower outdoor and social activities in dementia. However, actual ICT-based devices have limited functionality and impact, mainly limited to safety. What is an ideal operational framework to enhance this field to support outdoor and social activities? Review of literature and cross-disciplinary expert discussion. A situation-aware ICT requires a flexible fine-tuning by stakeholders of system usability and complexity of function, and of user safety and autonomy. It should operate by artificial intelligence/machine learning and should reflect harmonized stakeholder values, social context, and user residual cognitive functions. ICT services should be proposed at the prodromal stage of dementia and should be carefully validated within the life space of users in terms of quality of life, social activities, and costs. The operational framework has the potential to produce ICT and services with high clinical impact but requires substantial investment. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Contribution of road traffic to ambient fine particle concentrations (PM{sub 10}) in Switzerland

Energy Technology Data Exchange (ETDEWEB)

Hueglin, Ch.; Devos, W.; Gehrig, R.; Hofer, P.; Kobler, J. [Swiss Federal Laboratoires for Materials Testing and Research, EMPA, Dubendorf (Switzerland); Stahel, W.A. [Seminar for Statistics, ETH Zurich (Switzerland); Baltensperger, U. [Paul Scherrer Institute, Villigen PSI (Switzerland); Monn, Ch. [Institute for Hygiene and Applied Physiology, ETH Zurich (Switzerland)

2000-07-01

A multivariate receptor model was applied to estimate the contribution of road traffic to ambient levels of fine particles (PM{sub 10}) at different locations in Switzerland. At two roadside sites with heavy local traffic, the road traffic was found to account for 46% and 64% of PM{sub 10}. At an urban background site, the estimated average road traffic contribution was 34%, whereas a slightly higher value was obtained at a suburban site (36%). This results are in good agreement with the findings of a recent study, where a conceptually different approach (dispersion modelling) was applied. (authors)

Exposure to ultrafine particles, intracellular production of reactive oxygen species in leukocytes and altered levels of endothelial progenitor cells

International Nuclear Information System (INIS)

Jantzen, Kim; Møller, Peter; Karottki, Dorina Gabriela; Olsen, Yulia; Bekö, Gabriel; Clausen, Geo; Hersoug, Lars-Georg; Loft, Steffen

2016-01-01

Exposure to particles in the fine and ultrafine size range has been linked to induction of low-grade systemic inflammation, oxidative stress and development of cardiovascular diseases. Declining levels of endothelial progenitor cells within systemic circulation have likewise been linked to progression of cardiovascular diseases. The objective was to determine if exposure to fine and ultrafine particles from indoor and outdoor sources, assessed by personal and residential indoor monitoring, is associated with altered levels of endothelial progenitor cells, and whether such effects are related to leukocyte-mediated oxidative stress. The study utilized a cross sectional design performed in 58 study participants from a larger cohort. Levels of circulating endothelial progenitor cells, defined as either late (CD34 + KDR + cells) or early (CD34 + CD133 + KDR + cells) subsets were measured using polychromatic flow cytometry. We additionally measured production of reactive oxygen species in leukocyte subsets (lymphocytes, monocytes and granulocytes) by flow cytometry using intracellular 2′,7′-dichlorofluoroscein. The measurements encompassed both basal levels of reactive oxygen species production and capacity for reactive oxygen species production for each leukocyte subset. We found that the late endothelial progenitor subset was negatively associated with levels of ultrafine particles measured within the participant residences and with reactive oxygen species production capacity in lymphocytes. Additionally, the early endothelial progenitor cell levels were positively associated with a personalised measure of ultrafine particle exposure and negatively associated with both basal and capacity for reactive oxygen species production in lymphocytes and granulocytes, respectively. Our results indicate that exposure to fine and ultrafine particles derived from indoor sources may have adverse effects on human vascular health.

Physical characterization of the fine particle emissions from commercial aircraft engines during the Aircraft Particle Emissions eXperiment (APEX) 1-3

Science.gov (United States)

Kinsey, John S.; Dong, Yuanji; Williams, D. Craig; Logan, Russell

2010-06-01

The fine particulate matter (PM) emissions from nine commercial aircraft engine models were determined by plume sampling during the three field campaigns of the Aircraft Particle Emissions Experiment (APEX). Ground-based measurements were made primarily at 30 m behind the engine for PM mass and number concentration, particle size distribution, and total volatile matter using both time-integrated and continuous sampling techniques. The experimental results showed a PM mass emission index (EI) ranging from 10 to 550 mg kg -1 fuel depending on engine type and test parameters as well as a characteristic U-shaped curve of the mass EI with increasing fuel flow for the turbofan engines tested. Also, the Teflon filter sampling indicated that ˜40-80% of the total PM mass on a test-average basis was comprised of volatile matter (sulfur and organics) for most engines sampled. The number EIs, on the other hand, varied from ˜10 15 to 10 17 particles kg -1 fuel with the turbofan engines exhibiting a logarithmic decay with increasing fuel flow. Finally, the particle size distributions of the emissions exhibited a single primary mode that were lognormally distributed with a minor accumulation mode also observed at higher powers for all engines tested. The geometric (number) mean particle diameter ranged from 9.4 to 37 nm and the geometric standard deviation ranged from 1.3 to 2.3 depending on engine type, fuel flow, and test conditions.

Formation and alteration of airborne particles in the subway environment.

Science.gov (United States)

Moreno, T; Querol, X; Martins, V; Minguillón, M C; Reche, C; Ku, L H; Eun, H R; Ahn, K H; Capdevila, M; de Miguel, E

2017-01-25

Most particles in the rail subway environment are sub-micron sized ferruginous flakes and splinters generated mechanically by frictional wear of brake pads, wheels and rails. To better understand the mechanisms of formation and the alteration processes affecting inhalable particles in subways, PM samples (1-2.5 μm and 2.5-10 μm) were collected in the Barcelona Metro and then studied under a scanning electron microscope. Most particles in these samples are hematitic (up to 88%), with relatively minor amounts of mineral matter (up to 9%) and sulphates (up to 5%). Detailed microscopy (using back scattered and TEM-DRX imaging) reveals how many of the metallic particles comprise the metallic Fe nucleus surrounded by hematite (Fe 2 O 3 ) and a coating of sulphate and chloride salts mixed with mineral matter (including Ca-carbonates, clay minerals and quartz). These observations record the emission of fine to ultrafine FePM by frictional wear at elevated temperatures that promote rapid partial (or complete) oxidation of the native metal. Water condensing on the PM surface during cooling leads to the adsorption of inorganic mineral particles that coat the iron oxide. The distinctively layered polymineralic structure that results from these processes is peculiar to particles generated in the subway environment and very different from PM typically inhaled outdoors.

Impact of meteorological conditions on airborne fine particle composition and secondary pollutant characteristics in urban area during winter-time

Directory of Open Access Journals (Sweden)

Klaus Schäfer

2016-06-01

Full Text Available The assessment of airborne fine particle composition and secondary pollutant characteristics in the case of Augsburg, Germany, during winter (31 January–12 March 2010 is studied on the basis of aerosol mass spectrometry (3 non-refractory components and organic matter, 3 positive matrix factorizations (PMF factors, particle size distributions (PSD, 5 size modes, 5 PMF factors, further air pollutant mass concentrations (7 gases and VOC, black carbon, PM10, PM2.5 and meteorological measurements, including mixing layer height (MLH, with one-hourly temporal resolution. Data were subjectively assigned to 10 temporal phases which are characterised by different meteorological influences and air pollutant concentrations. In each phase hierarchical clustering analysis with the Ward method was applied to the correlations of air pollutants, PM components, PM source contributions and PSD modes and correlations of these data with all meteorological parameters. This analysis resulted in different degrees of sensitivities of these air pollutant data to single meteorological parameters. It is generally found that wind speed (negatively, MLH (negatively, relative humidity (positively and wind direction influence primary pollutant and accumulation mode particle (size range 100–500 nm concentrations. Temperature (negatively, absolute humidity (negatively and also relative humidity (positively are relevant for secondary compounds of PM and particle (PM2.5, PM10 mass concentrations. NO, nucleation and Aitken mode particle and the fresh traffic aerosol concentrations are only weakly dependent on meteorological parameters and thus are driven by emissions. These daily variation data analyses provide new, detailed meteorological influences on air pollutant data with the focus on fine particle composition and secondary pollutant characteristics and can explain major parts of certain PM component and gaseous pollutant exposure.

Fine sediment erodibility in Lake Okeechobee, Florida

OpenAIRE

Mehta, Ashish J.; Hwang, Kyu-Nam

1989-01-01

The critical need to predict the turbidity in water due to fine-grained sediment suspension under wave action over mud deposits for sedimentation and erosion studies, as well as sorbed contaminant transport, is well known. Since fall velocities of fine sediment particles are very small, they can be easily transported by hydrodynamic flows such as waves and currents. The presence of these particles in the water column affects accoustic transmission, heat absorption and depth of ...

Evaluation of methods for the physical characterization of the fine particle emissions from two residential wood combustion appliances

Science.gov (United States)

Kinsey, John S.; Kariher, Peter H.; Dong, Yuanji

The fine particle emissions from a U. S. certified non-catalytic wood stove and a zero-clearance fireplace burning Quercus rubra L. (northern red oak) and Pseudotsuga menziesii (Douglas fir) cordwood each at two different moisture levels were determined. Emission testing was performed using both time-integrated and continuous instrumentation for total particle mass, particle number, particle size distribution, and fixed combustion gases using an atmospheric wind tunnel, full-flow laboratory dilution tunnel, and dilution stack sampler with a comparison made between the three dilution systems and two sampling filter types. The total mass emission factors (EFs) for all dilution systems and filter media are extremely variable ranging from fireplace emissions burning wet oak averaged 11 g kg -1. A substantial number of ultrafine particles in the accumulation size range were also observed during all tests as determined by an Electrical Low Pressure Impactor (ELPI) and Scanning Mobility Particle Sizer. The PM-2.5 (particles ≤2.5 μm in aerodynamic diameter) fractions determined from the ELPI electrometer data ranged from 93 to 98% (mass) depending on appliance type as reported previously by Hays et al. (Aerosol Science, 34, 1061, 2003).

Table - Impacts of the Proposed Transport Rule on Counties with Monitors Projected to have Ozone and/or Fine Particle Air Quality Problems

Science.gov (United States)

This table shows the impacts of the proposed Transport Rule on Counties with Monitors Projected to have Ozone and/or Fine Particle Air Quality Problems, both with and without the Cross-State Air Pollution Rule.

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

International Nuclear Information System (INIS)

Lin, C.-C.; Chen, S.-J.; Huang, K.-L.; Lee, W.-J.; Lin, W.-Y.; Liao, C.-J.; Chaung, H.-C.; Chiu, C.-H.

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. - NO 3 - > SO 4 2- in mass ratio, different from common observations in rural areas, was found in (particularly the nano) traffic-associated particles

Preparation of nickel-based amorphous alloys with finely dispersed lead and lead-bismuth particles and their superconducting properties

International Nuclear Information System (INIS)

Inoue, A.; Oguchi, M.; Harakawa, Y.; Masumoto, T.; Matsuzaki, K.

1986-01-01

The application of the melt-quenching technique to Ni-Si-B-Pb, Ni-P-B-Pb, Ni-Si-B-Pb-Bi and Ni-P-B-Pb-Bi alloys containing immiscible elements such as lead and bismuth has been tried and it has been found to result in the formation of a new type of material consisting of fine fcc Pb or hcp epsilon(Pb-Bi) + bct X(Pb-Bi) particles dispersed uniformly in the nickel-based amorphous matrix. The particle size and interparticle distance were 1 to 3 and 1 to 4 μm, respectively, for the lead phase, and less than 0.2 to 0.5 μm and 0.2 to 1.0 μm for the Pb-Bi phase. The uniform dispersion of such fine particles into the amorphous matrix was achieved in the composition range below about 6 at% Pb and 7 at% (Pb+Bi). Additionally, these amorphous alloys have been found to exhibit a superconductivity by the proximity effect of fcc Pb or epsilon(Pb-Bi) superconducting particles. The transition temperature Tsub(c) was in the range 6.8 to 7.5 K for the Ni-Si (or P)-B-Pb alloys and 8.6 to 8.8 K for the Ni-Si (or P)-B-Pb-Bi alloys. The upper critical field Hsub(c2) and the critical current density Jsub(c) for (Nisub(0.8)Psub(0.1)Bsub(0.1)) 95 Pb 3 Bi 2 at 4.2 K were, respectively, about 1.6 T and of the order of 7 x 10 7 Am -2 at zero applied field. (author)

Re-evaluation of the Pressure Effect for Nucleation in Laminar Flow Diffusion Chamber Experiments with Fluent and the Fine Particle Model

Czech Academy of Sciences Publication Activity Database

Herrmann, E.; Hyvärinen, A.-P.; Brus, David; Lihavainen, H.; Kulmala, M.

2009-01-01

Roč. 113, č. 8 (2009), s. 1434-1439 ISSN 1089-5639 Institutional research plan: CEZ:AV0Z40720504 Keywords : laminar flow diffusion chamber * experimental data * fine particle model Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.899, year: 2009

The Role of Fine Sediment Content on Soil Consolidation and Debris Flows Development after Earthquake

Science.gov (United States)

Lyu, L.; Xu, M., III; Wang, Z.

2017-12-01

Fine sediment has been identified as an important factor determining the critical runoff that initiates debris flows because its contribution to shear strength through consolidation. Especially, owing to the 2008 Wenchuan earthquake in China enormous of loose sediment with different fractions of fine particles was eroded and supplied as materials for debris flows. The loose materials are gradually consolidated along with time, and therefore stronger rainfall is required to overcome the shear strength and to initiate debris flows. In this study, flume experiments were performed to explore soil consolidation and shear strength on mass failure and debris flow initiation under the conditions that different fractions of fine sediment were contained in the materials. Under the low content of fine sediment conditions (mass percentages: 0-10%), the debris flows formed with large pores and low shear strength and thus fine particles were too few to fill up the pores among the coarse particles. The consolidation rate was mostly influenced by the content of the fine particles. Consolidation of fine particles caused an increase of the shear strength and decrease of the rainfall infiltration, and therefore, debris flow initiation required stronger rainfall as the consolidation of the fine particles developed.

Outdoor Classrooms

Science.gov (United States)

Mayes, Valynda

2010-01-01

An outdoor classroom is the ideal vehicle for community involvement: Parents, native plant societies, 4-H, garden clubs, and master naturalists are all resources waiting to be tapped, as are local businesses offering support. If you enlist your community in the development and maintenance of your outdoor classroom, the entire community will…

Chemical characterzation of fine particle emissions from the fireplace combustion of woods grown in the Southern United States.

Science.gov (United States)

Fine, Philip M; Cass, Glen R; Simoneit, Bernd R T

2002-04-01

The fireplace combustion of wood is a significant and largely unregulated source of fine particle pollution in the United States. Source apportionment techniques that use particulate organic compounds as tracers have been successful in determining the contribution of wood smoke to ambient fine particle levels in specific areas in California. To apply these techniques to the rest of the United States, the differences in emissions profiles between different wood smoke sources and fuel types should be resolved. To this end, a series of fireplace source tests was conducted on six fuel wood species found in the Southern United States to determine fine particulate emission factors for total mass, ionic and elemental species, elemental and organic carbon, and over 250 individual organic compounds. The wood species tested, chosen for their high abundance and availability in the Southern U.S. region, were yellow poplar, white ash, sweetgum, mockernut hickory, loblolly pine, and slash pine. The differences in the emissions of compounds such as substituted phenols and resin acids help to distinguish between the smoke from hardwood and softwood combustion. Levoglucosan, a cellulose pyrolysis product which may serve as a tracer for wood smoke in general, was quantified in the emissions from all the wood species burned. The furofuran lignan, yangambin, which was emitted in significant quantities from yellow poplar combustion and not detected in any of the other North American wood smokes, is a potential species-specific molecular tracer which may be useful in qualitatively identifying particulate emissions from a specific geographical area where yellow poplar is being burned.

Fine particles in homes of predominantly low-income families with children and smokers: Key physical and behavioral determinants to inform indoor-air-quality interventions.

Science.gov (United States)

Klepeis, Neil E; Bellettiere, John; Hughes, Suzanne C; Nguyen, Benjamin; Berardi, Vincent; Liles, Sandy; Obayashi, Saori; Hofstetter, C Richard; Blumberg, Elaine; Hovell, Melbourne F

2017-01-01

Children are at risk for adverse health outcomes from occupant-controllable indoor airborne contaminants in their homes. Data are needed to design residential interventions for reducing low-income children's pollutant exposure. Using customized air quality monitors, we continuously measured fine particle counts (0.5 to 2.5 microns) over a week in living areas of predominantly low-income households in San Diego, California, with at least one child (under age 14) and at least one cigarette smoker. We performed retrospective interviews on home characteristics, and particle source and ventilation activities occurring during the week of monitoring. We explored the relationship between weekly mean particle counts and interview responses using graphical visualization and multivariable linear regression (base sample n = 262; complete cases n = 193). We found associations of higher weekly mean particle counts with reports of indoor smoking of cigarettes or marijuana, as well as with frying food, using candles or incense, and house cleaning. Lower particle levels were associated with larger homes. We did not observe an association between lower mean particle counts and reports of opening windows, using kitchen exhaust fans, or other ventilation activities. Our findings about sources of fine airborne particles and their mitigation can inform future studies that investigate more effective feedback on residential indoor-air-quality and better strategies for reducing occupant exposures.

Fine particles in homes of predominantly low-income families with children and smokers: Key physical and behavioral determinants to inform indoor-air-quality interventions.

Directory of Open Access Journals (Sweden)

Neil E Klepeis

Full Text Available Children are at risk for adverse health outcomes from occupant-controllable indoor airborne contaminants in their homes. Data are needed to design residential interventions for reducing low-income children's pollutant exposure. Using customized air quality monitors, we continuously measured fine particle counts (0.5 to 2.5 microns over a week in living areas of predominantly low-income households in San Diego, California, with at least one child (under age 14 and at least one cigarette smoker. We performed retrospective interviews on home characteristics, and particle source and ventilation activities occurring during the week of monitoring. We explored the relationship between weekly mean particle counts and interview responses using graphical visualization and multivariable linear regression (base sample n = 262; complete cases n = 193. We found associations of higher weekly mean particle counts with reports of indoor smoking of cigarettes or marijuana, as well as with frying food, using candles or incense, and house cleaning. Lower particle levels were associated with larger homes. We did not observe an association between lower mean particle counts and reports of opening windows, using kitchen exhaust fans, or other ventilation activities. Our findings about sources of fine airborne particles and their mitigation can inform future studies that investigate more effective feedback on residential indoor-air-quality and better strategies for reducing occupant exposures.

A novel field measurement method for determining fine particle and gas emissions from residential wood combustion

Science.gov (United States)

Tissari, Jarkko; Hytönen, Kati; Lyyränen, Jussi; Jokiniemi, Jorma

Emission data from residential wood combustion are usually obtained on test stands in the laboratory but these measurements do not correspond to the operational conditions in the field because of the technological boundary conditions (e.g. testing protocol, environmental and draught conditions). The field measurements take into account the habitual practice of the operators and provide the more reliable results needed for emission inventories. In this study, a workable and compact method for measuring emissions from residential wood combustion in winter conditions was developed. The emissions for fine particle, gaseous and PAH compounds as well as particle composition in real operational conditions were measured from seven different appliances. The measurement technique worked well and was evidently suitable for winter conditions. It was easy and fast to use, and no construction scaffold was needed. The dilution of the sample with the combination of a porous tube diluter and an ejector diluter was well suited to field measurement. The results indicate that the emissions of total volatile organic carbon (TVOC) (17 g kg -1 (of dry wood burned)), carbon monoxide (CO) (120 g kg -1) and fine particle mass (PM 1) (2.7 g kg -1) from the sauna stove were higher than in the other measured appliances. In the masonry heaters, baking oven and stove, the emissions were 2.9-9 g kg -1 TVOC, 28-68 g kg -1 CO and 0.6-1.6 g kg -1 PM 1. The emission of 12 PAHs (PAH 12) from the sauna stove was 164 mg kg -1 and consisted mainly of PAHs with four benzene rings in their structure. PAH 12 emission from other appliances was, on average, 21 mg kg -1 and was dominated by 2-ring PAHs. These results indicate that despite the non-optimal operational practices in the field, the emissions did not differ markedly from the laboratory measurements.

Study of fine particles (PM2.5) during the dry-hot time in the Toluca city

International Nuclear Information System (INIS)

Rosendo G, V.; Aldape U, F.

2007-01-01

The first obtained results of the analysis of the fine fraction particulate material (PM 2.5 ) samples collected in the Toluca City are presented. The samples analyzed are part of a more extensive campaign that contemplates the low project the one which one carries out this work and that it integrates three climatic times (dry-hot, of rains and dry-cold time) with the purpose of investigating the events of contamination in one complete year. The obtained results correspond to the dry-hot time and its include mainly the database starting from which the temporal variation graphs were obtained, the correlations among elements and the enrichment factor, as well as a multiple correlation analysis. Additionally the gravimetry was measured. Its are not observed significant episodes, however, it was found an element of the traces order, little common in other atmospheric studies as it is arsenic. From the gravimetry it was deduced that the air quality standard of fine particle, it does not violate. (Author)

Assessing and reducing fine and ultrafine particles inside Los Angeles taxis

Science.gov (United States)

Yu, Nu; Shu, Shi; Lin, Yan; Zhu, Yifang

2018-05-01

Taxi drivers and passengers are exposed to high levels of traffic-related air pollutants, but their exposures to fine (PM2.5) and ultrafine particles (UFPs) and related mitigation strategies are rarely explored. In this study, UFP and PM2.5 concentrations were monitored concurrently inside and outside of 22 taxis under different ventilation and mitigation conditions. Under realistic working conditions (no mitigation; NM), the average UFP and PM2.5 levels inside taxis were 1.46 × 104 particles/cm3 and 26 μg/m3, respectively. When the taxi ventilation was set to outside air mode and the windows kept closed, in-cabin UFP and PM2.5 concentrations are significantly associated with on-road concentrations, driving speed, and cabin air filter usage. The average in-cabin to on-roadway (I/O) ratios for UFP and PM2.5 were reduced from 0.60 to 0.75 under NM, to 0.47 and 0.52 under the most stringent mitigation strategy of keeping the windows closed and operating a high efficiency cabin air filter (WC + HECA). Among all tested taxi models, Toyota Prius exhibited the lowest UFP and PM2.5 I/O ratios under WC + HECA. Switching cabin air filters from the originally equipped manufacturer filter (OEM) to a HECA filter reduced the UFP and PM2.5 I/O ratios most effectively in Toyota Prius taxis as well.

Cement waste form development for ion-exchange resins and fine particles ILW of AREVA La Hague Reprocessing Plant

International Nuclear Information System (INIS)

Chartier, D.; Sanchez-Canet, J.; Avril, D.; Roussel, C.; Pineau, J.N.

2015-01-01

Wastes have been temporarily stored in dedicated silos in La Hague reprocessing plant. These wastes are to be retrieved in the near future and to be conditioned for final disposal. Some of these wastes are supposed to be encapsulated in cement matrix and, depending on the chemical composition of the waste streams, several projects are presently ongoing. The present article aims to focus on one amongst these cement encapsulation relevant projects, namely the conditioning of a mix of spent ion-exchange resins (from filtration of pool) and fine particles (insoluble fission products from spent fuel dissolution and Zircaloy and stainless steel fines from cladding shearing). The project, aims to retrieve these wastes from a silo, separate the resins and fine particles from the other waste (hulls and end pieces), in order to encapsulate the intermediate-level fines and resins in a cement matrix. The waste forms will be produced in AREVA's La Hague reprocessing plant, prior to being sent as intermediate-level waste to a long-term repository. The cement formulation developments were initially carried out at a small scale at C.E.A. Marcoule on surrogate wastes. One of the main issues that were considered was the chemical compatibility between waste and cement matrix. Indeed, swelling phenomena are sometimes reported when ion exchange resins are embedded in cement matrixes such as Portland cement. This kind of destructive phenomenon has been prevented by the use of cement containing a high amount of ground granulated blast furnace slag. The impact of the variability of ionic charge of the resins on the waste form's properties has also been addressed in order to comfort the results obtained on the reference ionic charge of resins NaNO 3 . Once the results obtained were satisfactory, intermediate scale and full scale tests were performed by AREVA. These tests have focused on adjusting the mixing process and controlling the thermal properties of the mix during setting

Concentrations and size distributions of fine aerosol particles measured at roof level in urban zone

Science.gov (United States)

Despiau, S.; Croci, D.

2007-05-01

During the experimental Field Experiments to Constrain Models of Atmospheric Pollution and Transport of Emissions (ESCOMPTE) campaign in June-July 2001, concentrations and size distributions of fine particles (14-722 nm) were measured at roof level in downtown Marseille (France). Part of the campaign was dedicated to the study of aerosol behavior in relation to strong photochemical events (which were identified as "IOP" days) and their regional modeling. The analysis of the concentration variations and the evolution of average diurnal size distribution showed that an "IOP day" is not characterized by a specific concentration or its variation, nor by a specific evolution of the average size distribution. The morning traffic rush is detected at roof level by a net increase in particle concentration over the whole size range measured, indicating a production of ultrafine particles by the traffic but also the raising to roof level of particles of the accumulation mode. The increase is observed about 1 hour after the traffic peak at street level, which is characterized by strong increases in NOx and CO concentrations. The corresponding flux of particles at roof level has been estimated around 3 × 104 cm-2 s-1. A specific signature characterized by a strong and rapid burst of concentration (factor 2 to 4 in 15 min) of particles between 25 and 50 nm, independent of the traffic source, has been detected on six occasions during the campaign. These events occur systematically around noon, in cases of strong radiation, low relative humidity, and common wind direction. Despite the high-diameter value of these particles, it is suggested that they could result from a specific "secondary aerosol process" event involving ozone, biogenic, and/or anthropogenic gas precursors like iodine and VOCs.

Fine filament NbTi superconductive composite

International Nuclear Information System (INIS)

Hong, S.; Grabinsky, G.; Marancik, W.; Pattanayak, D.

1986-01-01

The large superconducting magnet for the high energy physics accelerator requires fine filament composite to minimize the field error due to the persistent current in the filaments. New concepts toward the fine filament composite and its cable fabrication are discussed. Two-stage cables of fine wire with intermediate number of filaments were introduced. The first stage was six wires cables around one and in the second stage this was used to produce a Rutherford cable. The advantage of this process is in the ease of billet fabrication since the number of filaments in a single wire is within the range of easy billet fabrication. The disadvantage is in the cable fabrication. One of the major concerns in the fabrication of fine NbTi filaments composite in a copper matrix is the intermetallic compound formation during the extrusion and heat treatment steps. The hard intermetallic particles degrade the uniformity of the filaments and reduce the critical current density. The process of using Nb barrier between the filaments and copper matrix in order to prevent this CuTi intermetallic particle formation is described

Fear of moving outdoors and development of outdoor walking difficulty in older people.

Science.gov (United States)

Rantakokko, Merja; Mänty, Minna; Iwarsson, Susanne; Törmäkangas, Timo; Leinonen, Raija; Heikkinen, Eino; Rantanen, Taina

2009-04-01

To study which individual characteristics and environmental factors correlate with fear of moving outdoors and whether fear of moving outdoors predicts development of mobility limitation. Observational prospective cohort study and cross-sectional analyses. Community and research center. Seven hundred twenty-seven community-living people aged 75 to 81 were interviewed at baseline, of whom 314 took part in a 3.5-year follow-up. Fear of moving outdoors and its potential individual and environmental correlates were assessed at baseline. Perceived difficulties in walking 0.5 km and 2 km were assessed twice a year over a 3.5-year period. At baseline, 65% of the women and 29% of the men reported fear of moving outdoors. Poor socioeconomic status; musculoskeletal diseases; slow walking speed; and the presence of poor street conditions, hills in the nearby environment, and noisy traffic correlated with fear of moving outdoors. At the first 6-month follow-up, participants with fear of moving outdoors had more than four times the adjusted risk (odds ratio (OR)=4.6, 95% confidence interval (CI)=1.92-11.00) of developing difficulties in walking 0.5 km and a three times greater adjusted risk (OR=3.10, 95% CI=1.49-6.46) for developing difficulty in walking 2 km compared with those without fear. The difference in the prevalence of walking difficulties remained statistically significant over the 3.5-year follow-up (P=.02 and P=.009, respectively). Fear of moving outdoors is common in older adults and increases the risk of developing self-reported difficulties in walking 0.5 km and 2 km. Knowledge about individual and environmental factors underlying fear of moving outdoors and finding ways to alleviate fear of moving outdoors are important for community planning and prevention of disability.

An approach to assess the Particulate Matter exposure for the population living around a cement plant: modelling indoor air and particle deposition in the respiratory tract

Energy Technology Data Exchange (ETDEWEB)

Sánchez-Soberón, Francisco; Mari, Montse; Kumar, Vikas [Environmental Engineering Laboratory, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Catalonia (Spain); Rovira, Joaquim [Environmental Engineering Laboratory, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Catalonia (Spain); Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Catalonia (Spain); Nadal, Martí [Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Catalonia (Spain); Schuhmacher, Marta, E-mail: marta.schuhmacher@urv.cat [Environmental Engineering Laboratory, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Catalonia (Spain); Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Catalonia (Spain)

2015-11-15

In this paper we studied the exposure to three size fractions of outdoor particulate matter (PM{sub 10}, PM{sub 2.5}, and PM{sub 1}) collected in an area influenced by a cement plant. For that purpose, three groups of population were evaluated (children, adults and retired) in two seasons (summer and winter). Outdoor measured PM concentrations, as well as physiological parameters and activity patterns of the three groups of population were used as input data in two different models. The first one was an indoor air quality model, used to elucidate indoor PM concentrations in different microenvironments. The second one was a dosimetry model, used to evaluate the internal exposure and the distribution of the different PM fractions in the respiratory tract. Results from the indoor air quality model showed that special attention must be paid to the finest particles, since they penetrate indoors in a greater degree. Highest pulmonary doses for the three PM sizes were reported for retired people, being this a result of the high amount of time in outdoor environments exercising lightly. For children, the exposure was mainly influenced by the time they also spend outdoors, but in this case due to heavy intensity activities. It was noticed that deposition of fine particles was more significant in the pulmonary regions of children and retired people in comparison with adults, which has implications in the expected adverse health effects for those vulnerable groups of population. - Highlights: • PM deposition in the respiratory tract was evaluated for three population groups. • Activity patterns and different microenvironments were used in our calculation. • Outdoor activities are the main contributors to PM deposited mass. • Children experienced the highest deposition dose in the pulmonary region. • Retired registered the highest deposited mass in the respiratory tract as a whole.

An approach to assess the Particulate Matter exposure for the population living around a cement plant: modelling indoor air and particle deposition in the respiratory tract

International Nuclear Information System (INIS)

Sánchez-Soberón, Francisco; Mari, Montse; Kumar, Vikas; Rovira, Joaquim; Nadal, Martí; Schuhmacher, Marta

2015-01-01

In this paper we studied the exposure to three size fractions of outdoor particulate matter (PM 10 , PM 2.5 , and PM 1 ) collected in an area influenced by a cement plant. For that purpose, three groups of population were evaluated (children, adults and retired) in two seasons (summer and winter). Outdoor measured PM concentrations, as well as physiological parameters and activity patterns of the three groups of population were used as input data in two different models. The first one was an indoor air quality model, used to elucidate indoor PM concentrations in different microenvironments. The second one was a dosimetry model, used to evaluate the internal exposure and the distribution of the different PM fractions in the respiratory tract. Results from the indoor air quality model showed that special attention must be paid to the finest particles, since they penetrate indoors in a greater degree. Highest pulmonary doses for the three PM sizes were reported for retired people, being this a result of the high amount of time in outdoor environments exercising lightly. For children, the exposure was mainly influenced by the time they also spend outdoors, but in this case due to heavy intensity activities. It was noticed that deposition of fine particles was more significant in the pulmonary regions of children and retired people in comparison with adults, which has implications in the expected adverse health effects for those vulnerable groups of population. - Highlights: • PM deposition in the respiratory tract was evaluated for three population groups. • Activity patterns and different microenvironments were used in our calculation. • Outdoor activities are the main contributors to PM deposited mass. • Children experienced the highest deposition dose in the pulmonary region. • Retired registered the highest deposited mass in the respiratory tract as a whole.

Chemical compositions and sources of organic matter in fine particles of soils and sands from the vicinity of Kuwait city.

Science.gov (United States)

Rushdi, Ahmed I; Al-Zarban, Sheikha; Simoneit, Bernd R T

2006-09-01

Fine particles in the atmosphere from soil and sand resuspension contain a variety of organic compounds from natural biogenic and anthropogenic matter. Soil and sand samples from various sites near Kuwait city were collected, sieved to retain the fine particles, and extracted with a mixture of dichloromethane and methanol. The extracts were derivatized and analyzed by gas chromatography-mass spectrometry in order to characterize the chemical compositions and sources of the organic components. The major inputs of organic compounds were from both natural biogenic and anthropogenic sources in these samples. Vegetation was the major natural source of organic compounds and included n-alkanols, n-alkanoic acids, n-alkanes, sterols and triterpenoids. Saccharides had high concentrations (31-43%) in the sand dune and seafront samples, indicating sources from decomposed vegation materials and/or the presence of viable microbiota such as bacteria and fungi. Vehicular emission products, leakage of lubricating oils, discarded plastics and emissions from cooking operations were the major anthropogenic inputs in the samples from the urban areas. This input was mainly UCM, n-alkanes, hopanes, plasticizers and cholesterol, respectively.

Impact of Oxidant Gases on the Relationship between Outdoor Fine Particulate Air Pollution and Nonaccidental, Cardiovascular, and Respiratory Mortality.

Science.gov (United States)

Weichenthal, Scott; Pinault, Lauren L; Burnett, Richard T

2017-11-27

Outdoor fine particulate air pollution (PM 2.5 ) is known to increase mortality risk and is recognized as an important contributor to global disease burden. However, less is known about how oxidant gases may modify the chronic health effects of PM 2.5 . In this study, we examined how the oxidant capacity of O 3 and NO 2 (using a redox-weighted average, O x ) may modify the relationship between PM 2.5 and mortality in the 2001 Canadian Census Health and Environment Cohort. In total, 2,448,500 people were followed over a 10.6-year period. Each 3.86 µg/m 3 increase in PM 2.5 was associated with nonaccidental (Hazard Ratio (HR) = 1.095, 95% CI: 1.077, 1.112), cardiovascular (HR = 1.088, 95% CI: 1.059, 1.118), and respiratory mortality (HR = 1.110, 95% CI: 1.051, 1.171) in the highest tertile of O x whereas weaker/null associations were observed in the middle and lower tertiles. Analysis of joint non-linear concentration-response relationships for PM 2.5 and O x suggested threshold concentrations between approximately 23 and 25 ppb with O x concentrations above these values strengthening PM 2.5 -mortality associations. Overall, our findings suggest that oxidant gases enhance the chronic health risks of PM 2.5 . In some areas, reductions in O x concentrations may have the added benefit of reducing the public health impacts of PM 2.5 even if mass concentrations remain unchanged.

Carbon monoxide concentrations in outdoor wood-fired kitchens in Ouagadougou, Burkina Faso--implications for women's and children's health.

Science.gov (United States)

Thorsson, Sofia; Holmer, Björn; Andjelic, Andreas; Lindén, Jenny; Cimerman, Sandra; Barregard, Lars

2014-07-01

A majority of households in developing countries rely on biomass fuel for cooking, typically burned in open fires or simple stoves. The incomplete combustion of these fuels causes adverse health effects such as respiratory diseases, especially among women and children. However, quantitative data on pollution levels and on associated diseases are limited. We examined cooking habits and self-reported health in 31 households with outdoor open wood fires in Ouagadougou, Burkina Faso, using structured interviews. In eight households, carbon monoxide (CO) was measured using passive sampling. In addition, meteorology and ambient CO concentrations were assessed. The average CO concentration during cooking was 4.3 ppm, with a maximum of 65.3 ppm and minimum of 0.3 ppm (1-min values). A clear daily pattern was observed, with relatively low concentrations during the day and high during the evening, occasionally exceeding the World Health Organization 1- and 8-h guidelines when the air stabilised. On average, CO concentrations were 43 % higher in kitchens located in closed yards than in those located in open yards, showing that fireplace location affected the levels. Eye irritation and coughing among women and children were reported by 30 % of the households. Based on previously reported relations between CO concentrations and fine particles (health risk among women and children in households with outdoor open wood fires. The results suggest that burning should be limited between sunset and dawn and in areas with limited ventilation to reduce pollutions levels.

Fine Particulate Matter Pollution and Hospital Admissions for Respiratory Diseases in Beijing, China.

Science.gov (United States)

Xiong, Qiulin; Zhao, Wenji; Gong, Zhaoning; Zhao, Wenhui; Tang, Tao

2015-09-22

Fine particulate matter has become the premier air pollutant of Beijing in recent years, enormously impacting the environmental quality of the city and the health of the residents. Fine particles with aerodynamic diameters of 0~0.3 μm, 0.3~0.5 μm, and 0.5~1.0 μm, from the yeasr 2007 to 2012, were monitored, and the hospital data about respiratory diseases during the same period was gathered and calculated. Then the correlation between respiratory health and fine particles was studied by spatial analysis and grey correlation analysis. The results showed that the aerial fine particulate matter pollution was mainly distributed in the Zizhuyuan sub-district office. There was a certain association between respiratory health and fine particles. Outpatients with respiratory system disease in this study area were mostly located in the southeastern regions (Balizhuang sub-district office, Ganjiakou sub-district office, Wanshoulu sub-district office, and Yongdinglu sub-district office) and east-central regions (Zizhuyuan sub-district office and Shuangyushu sub-district office) of the study area. Correspondingly, PM₁ (particulate matter with aerodynamic diameter smaller than 1.0 um) concentrations in these regions were higher than those in any other regions. Grey correlation analysis results showed that the correlation degree of the fine particle concentration with the number of outpatients is high, and the smaller fine particles had more obvious effects on respiratory system disease than larger particles.

Fine Particulate Matter Pollution and Hospital Admissions for Respiratory Diseases in Beijing, China

Directory of Open Access Journals (Sweden)

Qiulin Xiong

2015-09-01

Full Text Available Fine particulate matter has become the premier air pollutant of Beijing in recent years, enormously impacting the environmental quality of the city and the health of the residents. Fine particles with aerodynamic diameters of 0~0.3 μm, 0.3~0.5 μm, and 0.5~1.0 μm, from the yeasr 2007 to 2012, were monitored, and the hospital data about respiratory diseases during the same period was gathered and calculated. Then the correlation between respiratory health and fine particles was studied by spatial analysis and grey correlation analysis. The results showed that the aerial fine particulate matter pollution was mainly distributed in the Zizhuyuan sub-district office. There was a certain association between respiratory health and fine particles. Outpatients with respiratory system disease in this study area were mostly located in the southeastern regions (Balizhuang sub-district office, Ganjiakou sub-district office, Wanshoulu sub-district office, and Yongdinglu sub-district office and east-central regions (Zizhuyuan sub-district office and Shuangyushu sub-district office of the study area. Correspondingly, PM1 (particulate matter with aerodynamic diameter smaller than 1.0 um concentrations in these regions were higher than those in any other regions. Grey correlation analysis results showed that the correlation degree of the fine particle concentration with the number of outpatients is high, and the smaller fine particles had more obvious effects on respiratory system disease than larger particles.

Fireplace and woodstove fine particle emissions from combustion of western Mediterranean wood types

Science.gov (United States)

Alves, Célia; Gonçalves, Cátia; Fernandes, Ana Patrícia; Tarelho, Luís; Pio, Casimiro

2011-08-01

Wood from seven species of trees grown in the Portuguese forest ( Pinus pinaster, Eucalyptus globulus, Quercus suber, Acacia longifolia, Quercus faginea, Olea europea and Quercus ilex rotundifolia), and briquettes produced from forest biomass waste were burned in a fireplace and in a woodstove to determine the chemical composition of fine particle (PM 2.5) emissions. Samples were analysed for organic and elemental carbon (OC/EC), water soluble ions (Na +, NH 4+, K +, Mg 2+, Ca 2+, Cl -, NO 3- and SO 42-) and 67 elements. The PM 2.5 emission factors (g kg - 1 fuel burned, dry basis) were in the ranges 9.9-20.2 and 4.2-16.3, respectively, for the fireplace and the woodstove. Organic carbon contributed to about 50% of the fine particle mass in the emissions from every wood species studied in both burning appliances. The carbonaceous component of PM 2.5 was dominated by organic carbon, accounting for more than 85% of the total carbon (TC): OC/TC ranged from 0.85 to 0.96 (avg. 0.92) for the fireplace and from 0.86 to 0.97 (avg. 0.93) for the woodstove. The water-soluble ions accounted for 0.64 to 11.3% of the PM 2.5 mass emitted from the fireplace, whereas mass fractions between 0.53 and 13.6% were obtained for the woodstove. The golden wattle wood smoke showed a much higher ionic content than the emissions from the other wood types. Trace elements represented 0.4 to 2.5% and 0.2 to 2.2% of the PM 2.5 mass emitted, respectively, from the fireplace and the woodstove, which corresponded to average total emissions of 132 ± 77.3 mg kg - 1 and 93.4 ± 60.8 mg kg - 1 of wood burned. Among these, K, Pb, Al, Mn and Sr were present in all samples. From the emission profiles of the individual experiments, composite wood combustion profiles are suggested with the aid of a cluster analysis.

Multi-criteria ranking and receptor modelling of airborne fine particles at three sites in the Pearl River Delta region of China.

Science.gov (United States)

Friend, Adrian J; Ayoko, Godwin A; Guo, Hai

2011-01-15

The multi-criteria decision making methods, Preference Ranking Organization METHods for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA), and the two-way Positive Matrix Factorization (PMF) receptor model were applied to airborne fine particle compositional data collected at three sites in Hong Kong during two monitoring campaigns held from November 2000 to October 2001 and November 2004 to October 2005. PROMETHEE/GAIA indicated that the three sites were worse during the later monitoring campaign, and that the order of the air quality at the sites during each campaign was: rural site>urban site>roadside site. The PMF analysis on the other hand, identified 6 common sources at all of the sites (diesel vehicle, fresh sea salt, secondary sulphate, soil, aged sea salt and oil combustion) which accounted for approximately 68.8±8.7% of the fine particle mass at the sites. In addition, road dust, gasoline vehicle, biomass burning, secondary nitrate, and metal processing were identified at some of the sites. Secondary sulphate was found to be the highest contributor to the fine particle mass at the rural and urban sites with vehicle emission as a high contributor to the roadside site. The PMF results are broadly similar to those obtained in a previous analysis by PCA/APCS. However, the PMF analysis resolved more factors at each site than the PCA/APCS. In addition, the study demonstrated that combined results from multi-criteria decision making analysis and receptor modelling can provide more detailed information that can be used to formulate the scientific basis for mitigating air pollution in the region. Copyright © 2010 Elsevier B.V. All rights reserved.

Ozone and limonene in indoor air: a source of submicron particle exposure.

Science.gov (United States)

Wainman, T; Zhang, J; Weschler, C J; Lioy, P J

2000-12-01

overall particle exposure. This study provides data for assessing the impact of outdoor ozone on indoor particles. This is important to determine the efficacy of the mass-based particulate matter standards in protecting public health because the indoor secondary particles can vary coincidently with the variations of outdoor fine particles in summer.

A Preliminary Experimental Investigation of Wet Fine Erosion in Two-Phase Flow

Science.gov (United States)

Ya, H. H.; Luthfi, Haziq; Ngo, Nguyet-Tran; Hassan, Suhaimi; Pao, William

2018-03-01

Solid particles below 62 μm is classified as fine. In oil producing operation, the most commonly used downhole sand screen can only capture solid particles of 140 μm and above. Most predictive erosion model is limited to particle size of 100 μm with single phase flow assumption because it is commonly believed that erosion due to particles below 100 μm is insignificant and typically ignored by oil and gas consultants when proposing facilities design. The objective of this paper is to investigate the impact of fines particle on mild steel plate in two-phase flow at different collision angles. A two phase flow loop was set up. The average size of fine particle was 60 μm, mixed with water with sand to water ratio at 1:65 wt/wt. The mild steel plates were oriented at three different impact angles which are -30°, 30° and 90°, with respect to the horizon. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface roughness and Vickers micro hardness techniques were used to quantify the effects of fine particle on the exposed surface.

Picobubble column flotation of fine coal

Energy Technology Data Exchange (ETDEWEB)

Daniel Tao; Samuel Yu; Xiaohua Zhou; R.Q. Honaker; B.K. Parekh [University of Kentucky, Lexington, KY (United States). Department of Mining Engineering

2008-01-15

Froth flotation is widely used in the coal industry to clean -28 mesh (0.6 mm) or -100 mesh (0.15 mm) fine coal. A successful recovery of particles by flotation depends on efficient particle-bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range, nominally 10-100 {mu}m, beyond which the flotation efficiency drops sharply. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles by increasing the probability of collision and attachment and reducing the probability of detachment. A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. Experimental results have shown that the use of picobubbles in a 5-cm diameter column flotation increased the combustible recovery of a highly floatable coal by up to 10% and that of a poorly floatable coal by up to 40%, depending on the feed rate, collector dosage, and other flotation conditions. 14 refs.

Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

Directory of Open Access Journals (Sweden)

A. Vara-Vela

2016-01-01

Full Text Available The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5;  ≤  2.5 µm in diameter in the Sao Paulo Metropolitan Area (SPMA in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August–6 September 2012 to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt contributed with 40–50 % of the total PM10 (i.e. those  ≤  10 µm in diameter concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the

Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

Science.gov (United States)

Vara-Vela, A.; Andrade, M. F.; Kumar, P.; Ynoue, R. Y.; Muñoz, A. G.

2016-01-01

The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5; ≤ 2.5 µm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem) model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August-6 September 2012) to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt) contributed with 40-50 % of the total PM10 (i.e. those ≤ 10 µm in diameter) concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the number of small particles impaired the

Improved process for contacting finely divided solid particles with gases

Energy Technology Data Exchange (ETDEWEB)

1952-07-30

A process of contacting solids and gases of the type in which finely divided solids are maintained in a dense fluidized state in a treating zone by means of an upflowing gaseous fluidizing medium wherein solid packing in the form of a body static contiguous elements is maintained in the treating zone. The size, shape, and arrangement of the elements constituting the packing being such as to define a labyrinth of passageways in which the finely divided solids are maintained in a fluidized state, and the finely divided solids are adapted to flow freely downwardly through the passageways in the absence of a gaseous fluidizing medium.

Turismo Activo y Outdoor Training: Metodología. (Adventure Sport Tourism and Outdoor Training: Methodology.

Directory of Open Access Journals (Sweden)

Vicente Gómez Encinas

2008-10-01

Full Text Available ResumenUno de los aspectos más atractivos que tiene el outdoor training es su supuesta capacidad para conseguir que los aprendizajes obtenidos a través de sus actividades sean transferidos a otros ámbitos de la vida personal y profesional de sus participantes. En este sentido, la clave está en la metodología empleada. Este artículo profundiza en las fases que estructuran el proceso formativo del outdoor training describiendo: 1 las bases folosóficas que lo apoyan y que están expresadas en la teoría de la “educación a través de la experiencia” y 2 las diferentes fases que estructuran el proceso de formación de un outdoor, haciendo una descripción en profundidad de cada una de ellas: a Pre-Outdoor (Análisis y valoración de las necesidades, diseño de la actividad y reunión previa a la actividad, b Outdoor, c Post-outdoor (Reflexión y transferencia, y d Seguimiento posterior.AbstractOne of the most attractive aspects that has the outdoor training is their supposed capacity to get that the learnings obtained through their activities are transferred to other environments of the personal life and their participants' professional. In this sense, the key is in the used methodology. This article deepens in the phases that structure the formative process of the outdoor training describing: 1 the philosophy´s bases that support this process and that are expressed in the theory of experiential education, and 2 the different phases that structure the process of formation of an outdoor, making a description in depth of each one of them: to Pre-Outdoor (Analysis and valuation of the necessities, design of the activity and previous meeting to the activity, b Outdoor, c Post-outdoor (Reflection and transfer, and d Later Pursuit.

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

Energy Technology Data Exchange (ETDEWEB)

Goix, Sylvaine [Université de Toulouse, INP-ENSAT, Av. Agrobiopôle, 31326 Castanet-Tolosan (France); UMR 5245 CNRS-INP-UPS, EcoLab (Laboratoire d' écologie fonctionnelle), Avenue de l' Agrobiopôle, BP 32607, 31326 Castanet-Tolosan (France); Lévêque, Thibaut [Université de Toulouse, INP-ENSAT, Av. Agrobiopôle, 31326 Castanet-Tolosan (France); UMR 5245 CNRS-INP-UPS, EcoLab (Laboratoire d' écologie fonctionnelle), Avenue de l' Agrobiopôle, BP 32607, 31326 Castanet-Tolosan (France); ADEME (French Agency for Environment and Energy Management), 20 Avenue du Grésillé, BP 90406, 49004 Angers Cedex 01 (France); Xiong, Tian-Tian [Université de Toulouse, INP-ENSAT, Av. Agrobiopôle, 31326 Castanet-Tolosan (France); UMR 5245 CNRS-INP-UPS, EcoLab (Laboratoire d' écologie fonctionnelle), Avenue de l' Agrobiopôle, BP 32607, 31326 Castanet-Tolosan (France); Schreck, Eva [Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées, Université de Toulouse, CNRS, IRD, 14 Avenue E. Belin, F-31400 Toulouse (France); 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}.

Particle size distribution and composition in a mechanically ventilated school building during air pollution episodes.

Science.gov (United States)

Parker, J L; Larson, R R; Eskelson, E; Wood, E M; Veranth, J M

2008-10-01

Particle count-based size distribution and PM(2.5) mass were monitored inside and outside an elementary school in Salt Lake City (UT, USA) during the winter atmospheric inversion season. The site is influenced by urban traffic and the airshed is subject to periods of high PM(2.5) concentration that is mainly submicron ammonium and nitrate. The school building has mechanical ventilation with filtration and variable-volume makeup air. Comparison of the indoor and outdoor particle size distribution on the five cleanest and five most polluted school days during the study showed that the ambient submicron particulate matter (PM) penetrated the building, but indoor concentrations were about one-eighth of outdoor levels. The indoor:outdoor PM(2.5) mass ratio averaged 0.12 and particle number ratio for sizes smaller than 1 microm averaged 0.13. The indoor submicron particle count and indoor PM(2.5) mass increased slightly during pollution episodes but remained well below outdoor levels. When the building was occupied the indoor coarse particle count was much higher than ambient levels. These results contribute to understanding the relationship between ambient monitoring station data and the actual human exposure inside institutional buildings. The study confirms that staying inside a mechanically ventilated building reduces exposure to outdoor submicron particles. This study supports the premise that remaining inside buildings during particulate matter (PM) pollution episodes reduces exposure to submicron PM. New data on a mechanically ventilated institutional building supplements similar studies made in residences.

Short-term Associations between Fine and Coarse Particulate Matter and Hospitalizations in Southern Europe: Results from the MED-PARTICLES Project

Science.gov (United States)

Samoli, Evangelia; Alessandrini, Ester; Cadum, Ennio; Ostro, Bart; Berti, Giovanna; Faustini, Annunziata; Jacquemin, Benedicte; Linares, Cristina; Pascal, Mathilde; Randi, Giorgia; Ranzi, Andrea; Stivanello, Elisa; Forastiere, Francesco

2013-01-01

Background: Evidence on the short-term effects of fine and coarse particles on morbidity in Europe is scarce and inconsistent. Objectives: We aimed to estimate the association between daily concentrations of fine and coarse particles with hospitalizations for cardiovascular and respiratory conditions in eight Southern European cities, within the MED-PARTICLES project. Methods: City-specific Poisson models were fitted to estimate associations of daily concentrations of particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5), ≤ 10 μm (PM10), and their difference (PM2.5–10) with daily counts of emergency hospitalizations for cardiovascular and respiratory diseases. We derived pooled estimates from random-effects meta-analysis and evaluated the robustness of results to co-pollutant exposure adjustment and model specification. Pooled concentration–response curves were estimated using a meta-smoothing approach. Results: We found significant associations between all PM fractions and cardiovascular admissions. Increases of 10 μg/m3 in PM2.5, 6.3 μg/m3 in PM2.5–10, and 14.4 μg/m3 in PM10 (lag 0–1 days) were associated with increases in cardiovascular admissions of 0.51% (95% CI: 0.12, 0.90%), 0.46% (95% CI: 0.10, 0.82%), and 0.53% (95% CI: 0.06, 1.00%), respectively. Stronger associations were estimated for respiratory hospitalizations, ranging from 1.15% (95% CI: 0.21, 2.11%) for PM10 to 1.36% (95% CI: 0.23, 2.49) for PM2.5 (lag 0–5 days). Conclusions: PM2.5 and PM2.5–10 were positively associated with cardiovascular and respiratory admissions in eight Mediterranean cities. Information on the short-term effects of different PM fractions on morbidity in Southern Europe will be useful to inform European policies on air quality standards. Citation: Stafoggia M, Samoli E, Alessandrini E, Cadum E, Ostro B, Berti G, Faustini A, Jacquemin B, Linares C, Pascal M, Randi G, Ranzi A, Stivanello E, Forastiere F, the MED-PARTICLES Study Group. 2013. Short

Electrode geometry effects on the collection efficiency of submicron and ultra-fine dust particles in spike-plate electrostatic precipitators

International Nuclear Information System (INIS)

Brocilo, D; Podlinski, J; Chang, J S; Mizeraczyk, J; Findlay, R D

2008-01-01

The collection efficiency of electrostatic precipitators for the submicron particles ranging from 0.1 to 1 μm and ultrafine particles smaller than 0. lμm is below the requirements of new PM2.5 emission regulations. In this work, numerical and experimental studies were conducted to examine the effect of discharge and collecting electrode geometries on the ion density and electric field profiles and consequently their effect on the particle surface charge and collection efficiency. The collection efficiency prediction was based on a modified Deutsche's equation after calculation of three dimensional electric field and ion density profiles. Whereas, the particle surface charge was obtained from diffusion and field charging models. Results show that the collection efficiency of fine particles for the spike-type discharge electrode when compared to the conventional wire-type was improved. Experimental validations were conducted on a bench scale electrostatic precipitator for total and partial collection efficiency of particles ranging in size from 0.01 to 20 μm and the results indicated that the model can be effectively applied for prototype design, modification, and scale-up of collecting and discharge electrodes.

Differences in Preferential Sorting of Fine Particles in the Panama Basin Over the Past 25 kyr: Effects on 230Th-derived Focusing Factors

Science.gov (United States)

Loveley, M. R.; Marcantonio, F.; Lyle, M. W.; Wang, J. K.

2013-12-01

In this study, we attempt to understand how preferential sorting of fine particles during redistribution processes in the Panama Basin affects the 230Th constant-flux proxy. Fine particles likely contain greater amounts of 230Th, so that preferential sorting of fine particles may bias sediment mass accumulation rates (MARs). We examined sediments that span the past 25 kyr from two new sediment cores retrieved within about 56 km of each other in the northern part of the basin (MV1013-01-'4JC', 5° 44.699'N 85° 45.498' W, 1730 m depth; MV1014-01-'8JC', 6° 14.038'N 86° 2.613' W, 1993 m depth). Core 4JC, closer to the ridge top that bounds the basin (Cocos Ridge), has a thin sediment drape, while the deeper core 8JC, has a thicker sediment drape and lies further from the ridge top. 230Th-derived focusing factors from 4JC are similar and suggest winnowing with average values of about 0.5 and 0.6 during the Holocene and the last glacial, respectively. For 8JC, calculated average focusing factors are significantly different and suggest focusing with values of about 2 during the Holocene and 4 during the last glacial. Since the two sites are close to each other, one would expect similar rain rates and, therefore, similar 230Th-derived MARs within similar windows of time, i.e., the rain rate should not vary significantly at each site temporally. In addition, the radiocarbon-derived sand (>63μm) MARs should behave similarly since coarser particles are likely not transported by bottom currents. Sand MARs are, indeed, similar during the Holocene and the last glacial at each site. During the last glacial, however, sand MARs are about a factor of 3 higher than those during the Holocene. On the other hand, there is little variability in the 230Th-derived MARs both spatially and temporally. We interpret the discrepancies between the radiocarbon-derived sand and 230Th-derived MARs as being due to preferential sorting of fine particles during the redistribution of sediments by

Formation of fine solid particles from aqueous solutions of sodium chloropalladate by gamma-ray irradiation

International Nuclear Information System (INIS)

Hatada, Motoyoshi; Fujita, Iwao; Korekawa, Kei-ichi.

1994-10-01

Studies have been carried out on the radiation chemical formation of palladium fine particles in argon saturated aqueous solutions of sodium chloropalladate without organic stabilizer. The solutions were irradiated with gamma-rays from a cobalt gamma-ray source and the irradiated solutions were subjected to the dynamic light scattering analysis for the particle diameter measurements, and to the UV-visible optical absorption spectroscopy for the measurements of turbidity (absorption at 700 nm) and remaining chloropalladate ion concentrations in the solution. In the solution of pH = 1.95 by HCl, the turbidity increased after the irradiation and then decreased with time. The concentration of remaining palladate ion in the solution decreased by the irradiation, but it gradually increased with time after the irradiation. These phenomena were qualitatively explained by the reaction scheme in that a precursor to the solid particles still exists in the solution after the irradiation was terminated, and that intermediates including the precursor reacted with chloride ion to re-form chloropalladate ions. The average diameter of the particles after the irradiation was ca. 20 nm and it increased with time to 40 nm at 2.75 kGy, and to 80 nm at 8.25 kGy absorption of radiation. The solution of pH = 0.65 by HCl was found to give lower yields of particles than those observed for the solution of pH = 1.95, and to give the particles of diameters about 150-200 nm. In the solution containing HClO 4 instead of HCl, palladium particles were also formed by the irradiation, whereas no backward reaction after the irradiation was observed due to the low concentration of chloride ion in the solution. The average diameter of the particles after the irradiation was about 300 nm and increased with time after the irradiation to a final values which was found to depend on pH of the solution and dose. (author)

The effect of limited availability of N or water on C allocation to fine roots and annual fine root turnover in Alnus incana and Salix viminalis.

Science.gov (United States)

Rytter, Rose-Marie

2013-09-01

The effect of limited nitrogen (N) or water availability on fine root growth and turnover was examined in two deciduous species, Alnus incana L. and Salix viminalis L., grown under three different regimes: (i) supply of N and water in amounts which would not hamper growth, (ii) limited N supply and (iii) limited water supply. Plants were grown outdoors during three seasons in covered and buried lysimeters placed in a stand structure and filled with quartz sand. Computer-controlled irrigation and fertilization were supplied through drip tubes. Production and turnover of fine roots were estimated by combining minirhizotron observations and core sampling, or by sequential core sampling. Annual turnover rates of fine roots water availability. Fine root production (treatments in Salix; i.e., absolute length and biomass production increased in the order: water limited treatment effects were detected for fine roots 1-2 mm. Proportionally more C was allocated to fine roots (≤2 mm) in N or water-limited Salix; 2.7 and 2.3 times the allocation to fine roots in the unlimited regime, respectively. Estimated input to soil organic carbon increased by ca. 20% at N limitation in Salix. However, future studies on fine root decomposition under various environmental conditions are required. Fine root growth responses to N or water limitation were less pronounced in Alnus, thus indicating species differences caused by N-fixing capacity and slower initial growth in Alnus, or higher fine root plasticity in Salix. A similar seasonal growth pattern across species and treatments suggested the influence of outer stimuli, such as temperature and light.

Chemical characterization and oxidative potential of particles emitted from open burning of cereal straws and rice husk under flaming and smoldering conditions

Science.gov (United States)

Fushimi, Akihiro; Saitoh, Katsumi; Hayashi, Kentaro; Ono, Keisuke; Fujitani, Yuji; Villalobos, Ana M.; Shelton, Brandon R.; Takami, Akinori; Tanabe, Kiyoshi; Schauer, James J.

2017-08-01

Open burning of crop residue is a major source of atmospheric fine particle emissions. We burned crop residues (rice straws, barley straws, wheat straws, and rice husks produced in Japan) in an outdoor chamber and measured particle mass, composition (elemental carbon: EC, organic carbon: OC, ions, elements, and organic species), and oxidative potential in the exhausts. The fine particulate emission factors from the literature were within the range of our values for rice straws but were 1.4-1.9 and 0.34-0.44 times higher than our measured values for barley straw and wheat straw, respectively. For rice husks and wheat straws, which typically lead to combustion conditions that are relatively mild, the EC content of the particles was less than 5%. Levoglucosan seems more suitable as a biomass burning marker than K+, since levoglucosan/OC ratios were more stable than K+/particulate mass ratios among crop species. Stigmasterol and β-sitosterol could also be used as markers of biomass burning with levoglucosan or instead of levoglucosan. Correlation analysis between chemical composition and combustion condition suggests that hot or flaming combustions enhance EC, K+, Cl- and polycyclic aromatic hydrocarbons emissions, while low-temperature or smoldering combustions enhance levoglucosan and water-soluble organic carbon emissions. Oxidative potential, measured with macrophage-based reactive oxygen species (ROS) assay and dithiothreitol (DTT) assay, of open burning fine particles per particulate mass as well as fine particulate emission factors were the highest for wheat straws and second highest for rice husks and rice straws. Oxidative potential per particulate mass was in the lower range of vehicle exhaust and atmosphere. These results suggest that the contribution of open burning is relatively small to the oxidative potential of atmospheric particles. In addition, oxidative potential (both ROS and DTT activities) correlated well with water-insoluble organic species

NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

Energy Technology Data Exchange (ETDEWEB)

Jost O.L. Wendt

2002-08-15

This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NOx and low NOx combustion conditions will be investigated (unstaged and staged combustion). Tradeoffs between CO2 control, NOx control, and inorganic fine particle and toxic metal emissions will be determined. Previous research has yielded data on trace metal partitioning for MSS by itself, with natural gas assist, for coal plus MSS combustion together, and for coal alone. We have re-evaluated the inhalation health effects of ash aerosol from combustion of MSS both by itself and also together with coal. We have concluded that ash from the co-combustion of MSS and coal is very much worse from an inhalation health point of view, than ash from either MSS by itself or coal by itself. The reason is that ZnO is not the ''bad actor'' as had been suspected before, but the culprit is, rather, sulfated Zn. The MSS supplies the Zn and the coal supplies the sulfur, and so it is the combination of coal and MSS that makes that process environmentally bad. If MSS is to be burned, it should be burned without coal, in the absence of sulfur.

PREFACE: 8th International Conference on Fine Particle Magnetism (ICFPM2013)

Science.gov (United States)

2014-06-01

The 8th International Conference on Fine Particle Magnetism (ICFPM) was held in Perpignan from 24 to 27 June 2013, and was the continuation of the previous meetings held in Bangor (1996), Rome (1991), Barcelona (1999), Pittsburg (2002), London (2004), Rome (2007) and Uppsala (2010). The next meeting will be organized by Profs. Robert D. Shull, George Hadjipanayis and Cindi Dennis, in 2016 at NIST, Gaithersburg (USA). ICFPM is a small-sized conference focused on the magnetism of nanoparticles. It provides an international forum for discussing the state-of-the-art understanding of physics of these systems, of their properties and the underlying phenomena, as approached from a variety of directions: theory and modelling, experiments on well characterized or model systems (both fabricated and synthetised), as well as experiments on technologically-relevant non-ideal systems. This meeting brought together about 120 participants working on experimental, theoretical and applied topics of the multidisciplinary research areas covered by magnetic nanoparticles, with focused interest on either single-particle or collective phenomena. The technical program of the conference was based on keynote conferences, invited talks, oral contributions and poster sessions, covering the following aspects: . Fabrication, synthesis, characterization . Single particle, surface and finite-size effects on magnetic properties . Magnetization dynamics, micro-wave assisted switching, dynamical coupling . Assemblies, collective effects, self-assembling and nanostructuring . Applications : hyperthermia, drug delivery, magneto-caloric, magneto-resistance, magneto-plasmonics, magnetic particle imaging This ICFPM edition was organized by the group Nanoscale Spin Systems of the laboratory PROMES of the CNRS (UPR8521), and Université de Perpignan Via Domitia. The meeting took place at the Congress Center of the city of Perpignan providing high-quality facilities for the technical program as well for the

9 CFR 3.27 - Facilities, outdoor.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Facilities, outdoor. 3.27 Section 3.27... Pigs and Hamsters Facilities and Operating Standards § 3.27 Facilities, outdoor. (a) Hamsters shall not be housed in outdoor facilities. (b) Guinea pigs shall not be housed in outdoor facilities unless...

Radiological dispersal device outdoor simulation test: Cesium chloride particle characteristics

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Don, E-mail: lee.sangdon@epa.gov [U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Snyder, Emily G.; Willis, Robert [U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Fischer, Robert; Gates-Anderson, Dianne; Sutton, Mark [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Viani, Brian [Simbol Mining Corp., Pleasanton, CA 94566 (United States); Drake, John [U.S. Environmental Protection Agency, Cincinnati, OH 45268 (United States); MacKinney, John [U.S. Department of Homeland Security, Washington, DC 20528 (United States)

2010-04-15

Particles were generated from the detonation of simulated radiological dispersal devices (RDDs) using non-radioactive CsCl powder and explosive C4. The physical and chemical properties of the resulting particles were characterized. Two RDD simulation tests were conducted at Lawrence Livermore National Laboratory: one of the simulated RDDs was positioned 1 m above a steel plate and the other was partially buried in soil. Particles were collected with filters at a distance of 150 m from the origin of the RDD device, and particle mass concentrations were monitored to identify the particle plume intensity using real time particle samplers. Particles collected on filters were analyzed via computer-controlled scanning electron microscopy coupled with energy dispersive X-ray spectrometry (CCSEM/EDX) to determine their size distribution, morphology, and chemical constituents. This analysis showed that particles generated by the detonation of explosives can be associated with other materials (e.g., soil) that are in close proximity to the RDD device and that the morphology and chemical makeup of the particles change depending on the interactions of the RDD device with the surrounding materials.

Radiological dispersal device outdoor simulation test: Cesium chloride particle characteristics

International Nuclear Information System (INIS)

Lee, Sang Don; Snyder, Emily G.; Willis, Robert; Fischer, Robert; Gates-Anderson, Dianne; Sutton, Mark; Viani, Brian; Drake, John; MacKinney, John

2010-01-01

Particles were generated from the detonation of simulated radiological dispersal devices (RDDs) using non-radioactive CsCl powder and explosive C4. The physical and chemical properties of the resulting particles were characterized. Two RDD simulation tests were conducted at Lawrence Livermore National Laboratory: one of the simulated RDDs was positioned 1 m above a steel plate and the other was partially buried in soil. Particles were collected with filters at a distance of 150 m from the origin of the RDD device, and particle mass concentrations were monitored to identify the particle plume intensity using real time particle samplers. Particles collected on filters were analyzed via computer-controlled scanning electron microscopy coupled with energy dispersive X-ray spectrometry (CCSEM/EDX) to determine their size distribution, morphology, and chemical constituents. This analysis showed that particles generated by the detonation of explosives can be associated with other materials (e.g., soil) that are in close proximity to the RDD device and that the morphology and chemical makeup of the particles change depending on the interactions of the RDD device with the surrounding materials.

[Pollution characteristics and source of the atmospheric fine particles and secondary inorganic compounds at Mount Dinghu in autumn season].

Science.gov (United States)

Liu, Zi-Rui; Wang, Yue-Si; Liu, Quan; Liu, Lu-Ning; Zhang, De-Qiang

2011-11-01

Real-time measurements of PM2.5, secondary inorganic compounds in PM2.5 (SO4(2-), NH4(+), and NO3(-)) and related gaseous pollutants were conducted at Mount Dinghu, a regional background station of the Pearl River Delta (PRD), in October and November 2008 by using a conventional R&P TEOM and a system of rapid collection of fine particles and ion chromatography (RCFP-IC). Sources and transportation of atmospheric particles during the experiment were discussed with principal component analysis and backward trajectories calculated using HYSPLIT model. The average daily mass concentrations of PM2.5 were 76.9 microg x m(-3) during sampling period, and average daily mass concentrations of SO4(2-), NH4(+), and NO3(-) were 20.0 microg x m(-3), 6.8 microg x m(-3) and 2.6 microg x m(-3), respectively. The sum of these three secondary inorganic compounds accounted for more than one third of the PM2.5 mass concentration, which had become the major source of atmospheric fine particles at Mount Dinghu. The diurnal variation of PM2.5, SO4(2-), and NH4(+) all showed a "bimodal" distribution with two peaks appeared at 10:00 am and at 16:00 pm, respectively, whereas NO3(-s) howed "single peak" distribution peaked at 10:00 am. The mass concentrations of SO4(2-) in PM2.5 had the similar diurnal variation with that of SO2, SO4(2-) in PM2.5 was mainly transformed from SO2, whereas NO3(-) showed difference diurnal variation with that of NO2, and the second conversion rate of NO2 was far lower than that of SO2. NH4(+) in PM2.5 existed mainly in the form of sulfate, nitrate and chloride. Both of principal component analysis and back trajectory analysis showed that the variations of PM2.5 and secondary inorganic compounds at Mount Dinghu were mainly affected by the long-range transport air mass passed over Guangzhou, Huizhou and other highly industrialized areas which carried air pollutants to the observation site, at the same time local sulfate originated from secondary formation also

Outdoor Education and Science Achievement

Science.gov (United States)

Rios, José M.; Brewer, Jessica

2014-01-01

Elementary students have limited opportunities to learn science in an outdoor setting at school. Some suggest this is partially due to a lack of teacher efficacy teaching in an outdoor setting. Yet the research literature indicates that outdoor learning experiences develop positive environmental attitudes and can positively affect science…

Picobubble enhanced column flotation of fine coal

Energy Technology Data Exchange (ETDEWEB)

Tao, D.; Yu, S.; Parekh, B.K. [University of Kentucky, Lexington, KY (United States). Mining Engineering

2006-07-01

The purpose is to study the effectiveness of picobubbles in the column flotation of -28 mesh fine coal particles. A flotation column with a picobubble generator was developed and tested for enhancing the recovery of ultrafine coal particles. The picobubble generator was designed using the hydrodynamic cavitation principle. A metallurgical and a steam coal were tested in the apparatus. The results show that the use of picobubbles in a 2in. flotation column increased the recovery of fine coal by 10 to 30%. The recovery rate varied with feed rate, collector dosage, and other column conditions. 40 refs., 8 figs., 2 tabs.

Health Benefits of Particle Filtration

OpenAIRE

Fisk, William J.

2013-01-01

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and as...

New methods and standards for fine dust

International Nuclear Information System (INIS)

Spielvogel, Juergen; Hartstock, Stefan; Grimm, Hans

2009-01-01

There seems to be common agreement that PM10 is a suboptimal quantity for the quantification of potential dangers from fine dust due to a number of reasons, notably because the chemical composition of the particles is not considered, because the size distribution is disregarded, and because of sampling artefacts. In a first step for improving the particle measurements, the European Community has published new directives for ambient air in June 2008 (EU 2008), which as a main part included new regulations for PM2.5 measurements, in addition to the further on valid regulations for PM10. The comparison of PM2.5 and PM10 may allow a source apportionment and a better assessment of the influence of fine dust on human health. The source apportionment may allow more effective fine dust reduction strategies.

Unexpected spatial impact of treatment plant discharges induced by episodic hydrodynamic events: Modelling Lagrangian transport of fine particles by Northern Current intrusions in the bays of Marseille (France).

Science.gov (United States)

Millet, Bertrand; Pinazo, Christel; Banaru, Daniela; Pagès, Rémi; Guiart, Pierre; Pairaud, Ivane

2018-01-01

Our study highlights the Lagrangian transport of solid particles discharged at the Marseille Wastewater Treatment Plant (WWTP), located at Cortiou on the southern coastline. We focused on episodic situations characterized by a coastal circulation pattern induced by intrusion events of the Northern Current (NC) on the continental shelf, associated with SE wind regimes. We computed, using MARS3D-RHOMA and ICHTHYOP models, the particle trajectories from a patch of 5.104 passive and conservative fine particles released at the WWTP outlet, during 2 chosen representative periods of intrusion of the NC in June 2008 and in October 2011, associated with S-SE and E-SE winds, respectively. Unexpected results highlighted that the amount of particles reaching the vulnerable shorelines of both northern and southern bays accounted for 21.2% and 46.3% of the WWTP initial patch, in June 2008 and October 2011, respectively. Finally, a conceptual diagram is proposed to highlight the mechanisms of dispersion within the bays of Marseille of the fine particles released at the WWTP outlet that have long been underestimated.

Outdoorsman: Outdoor Cooking.

Science.gov (United States)

Alberta Dept. of Agriculture, Edmonton.

This Outdoor Cookery manual provides information and instruction on the basic outdoor skills of building suitable cooking fires, handling fires safely, and storing food. The necessity of having the right kind of fire is stressed (high flames for boiling, low for stewing, and coals for frying and broiling). Tips on gauging temperature, what types…

Using monosaccharide anhydrides to estimate the impact of wood combustion on fine particles in the Helsinki Metropolitan Area

Energy Technology Data Exchange (ETDEWEB)

Saarnio, K.; Saarikoski, S. [Finnish Meteorological Institute, Helsinki (Finland); Niemi, J.V. [HSY Helsinki Region Environmental Services Authority, Helsinki (Finland)

2012-11-01

The spatiotemporal variation of ambient particles under the influence of biomass burning emissions was studied in the Helsinki Metropolitan Area (HMA) in selected periods during 2005-2009. Monosaccharide anhydrides (MAs; levoglucosan, mannosan and galactosan), commonly known biomass burning tracers, were used to estimate the wood combustion contribution to local particulate matter (PM) concentration levels at three urban background sites close to the city centre, and at three suburban sites influenced by local small-scale wood combustion. In the cold season (October-March), the mean MAs concentrations were 115-225 ng m{sup -3} and 83-98 ng m{sup -} {sup 3}at the suburban and urban sites, respectively. In the warm season, the mean MAs concentrations were low (19-78 ng m{sup -3}), excluding open land fire smoke episodes (222-378 ng m{sup -}3{sup )}. Regionally distributed wood combustion particles raised the levels over the whole HMA while particles from local wood combustion sources raised the level at suburban sites only. The estimated average contribution of wood combustion to fine particles (PM{sub 2.5}) ranged from 18% to 29% at the urban sites and from 31% to 66% at the suburban sites in the cold season. The PM measurements from ambient air and combustion experiments showed that the proportions of the three MAs can be utilised to separate the wildfire particles from residential wood combustion particles. (orig.)

A persisting secondhand smoke hazard in urban public places: results from fine particulate (PM2.5) air sampling.

Science.gov (United States)

Wilson, Nick; Edwards, Richard; Parry, Rhys

2011-03-04

To assess the need for additional smokefree settings, by measuring secondhand smoke (SHS) in a range of public places in an urban setting. Measurements were made in Wellington City during the 6-year period after the implementation of legislation that made indoor areas of restaurants and bars/pubs smokefree in December 2004, and up to 20 years after the 1990 legislation making most indoor workplaces smokefree. Fine particulate levels (PM2.5) were measured with a portable real-time airborne particle monitor. We collated data from our previously published work involving random sampling, purposeful sampling and convenience sampling of a wide range of settings (in 2006) and from additional sampling of selected indoor and outdoor areas (in 2007-2008 and 2010). The "outdoor" smoking areas of hospitality venues had the highest particulate levels, with a mean value of 72 mcg/m3 (range of maximum values 51-284 mcg/m3) (n=20 sampling periods). These levels are likely to create health hazards for some workers and patrons (i.e., when considered in relation to the WHO air quality guidelines). National survey data also indicate that these venues are the ones where SHS exposure is most frequently reported by non-smokers. Areas inside bars that were adjacent to "outdoor" smoking areas also had high levels, with a mean of 54 mcg/m3 (range of maximum values: 18-239 mcg/m3, for n=13 measurements). In all other settings mean levels were lower (means: 2-22 mcg/m3). These other settings included inside traditional style pubs/sports bars (n=10), bars (n=18), restaurants (n=9), cafes (n=5), inside public buildings (n=15), inside transportation settings (n=15), and various outdoor street/park settings (n=22). During the data collection in all settings made smokefree by law, there was only one occasion of a person observed smoking. The results suggest that compliance in pubs/bars and restaurants has remained extremely high in this city in the nearly six years since implementation of the

Outdoor smoking behaviour and support for outdoor smoking restrictions before and after France's national smoking ban.

Science.gov (United States)

Kennedy, Ryan David; Behm, Ilan; Craig, Lorraine; Thompson, Mary E; Fong, Geoffrey T; Guignard, Romain; Beck, Francois

2012-02-01

On January 1, 2008, the French government implemented a national ban on indoor smoking in hospitality venues. Survey results indicate the indoor ban has been successful at dramatically reducing indoor smoking; however, there are reports of an increased number of outdoor hospitality spaces (patios) where smoking can take place. This study sought to understand if the indoor ban simply moved smoking to the outdoors, and to assess levels of support for smoking restrictions in outdoor hospitality settings after the smoke-free law. Telephone interviews were conducted among 1067 adult smokers before and after the 2008 indoor ban as part of the International Tobacco Control (ITC) France Survey. Among other topics, this survey measures how the smoking ban has influenced smoking behaviour relevant to outdoor sections of hospitality venues. In addition, 414 non-smoking adults and 164 respondents who had quit smoking between waves were also asked about support for outdoor smoking restrictions. Reported smoking outdoors at cafés/pubs/bars increased from 33.6% of smokers at Wave 1 to 75.9% at Wave 2. At restaurants, smoking outdoors increased from 28.9% to 59.0%. There was also an increase in reported non-smoking for both visits to cafés/pubs/bars, and restaurants from 13.4% to 24.7%, and 30.4% to 40.8% respectively. The majority of smokers (74.5%), non-smokers (89.4%) and quitters (74.0%) support a partial or complete ban on smoking in outdoor areas of restaurants. The indoor smoking ban moved smoking to outdoor spaces; however, the ban is also associated with increased non-smoking behaviour. The majority of respondents support outdoor smoking restrictions in patio environments.

Co-formation of hydroperoxides and ultra-fine particles during the reactions of ozone with a complex VOC mixture under simulated indoor conditions

DEFF Research Database (Denmark)

Fan, Z.H.; Weschler, Charles J.; Han, IK

2005-01-01

In this study we examined the co-formation of hydrogen peroxide and other hydroperoxides (collectively presented as H2O2*) as well as submicron particles, including ultra-fine particles (UFP), resulting from the reactions of ozone (O-3) with a complex mixture of volatile organic compounds (VOCs...... higher than typical indoor levels. When O-3 was added to a 25-m(3) controlled environmental facility (CEF) containing the 23 VOC mixture, both H2O2* and submicron particles were formed. The 2-h average concentration of H2O2* was 1.89 +/- 0.30ppb, and the average total particle number concentration was 46...... to achieve saturated concentrations of the condensable organics. When the 2 terpenes were removed from the O-3/23 VOCs mixture, no H2O2* or particles were formed, indicating that the reactions of O-3 With the two terpenes were the key processes contributing to the formation of H2O2* and submicron particles...

Pulse-based electron spin transient nutation measurement of BaTiO3 fine particle: Identification of controversial signal around g = 2.00

Science.gov (United States)

Sawai, Takatoshi; Yamaguchi, Yoji; Kitamura, Noriko; Date, Tomotsugu; Konishi, Shinya; Taga, Kazuya; Tanaka, Katsuhisa

2018-05-01

Two dimensional pulse-based electron spin transient nutation (2D-ESTN) spectroscopy is a powerful tool for determining the spin quantum number and has been applied to BaTiO3 fine powder in order to identify the origin of the continuous wave electron spin resonance (CW-ESR) signal around g = 2.00. The signal is frequently observed in BaTiO3 ceramics, and the correlation between the signal intensity and positive temperature coefficient of resistivity (PTCR) properties has been reported to date. The CW-ESR spectrum of BaTiO3 fine particles synthesized by the sol-gel method shows a typical asymmetric signal at g = 2.004. The 2D-ESTN measurements of the sample clearly reveal that the signal belongs to the S = 5/2 high spin state, indicating that the signal is not due to a point defect as suggested by a number of researchers but rather to a transition metal ion. Our elemental analysis, as well as previous studies, indicates that the origin of the g = 2.004 signal is due to the presence of an Fe3+ impurity. The D value (second-order fine structure parameter) reveals that the origin of the signal is an Fe3+ center with distant charge compensation. In addition, we show a peculiar temperature dependence of the CW-ESR spectrum, suggesting that the phase transition behavior of a BaTiO3 fine particle is quite different from that of a bulk single crystal. Our identification does not contradict a vacancy-mediated mechanism for PTCR. However, it is incorrect to use the signal at g = 2.00 as evidence to support the vacancy-mediated mechanism.

Fines Classification Based on Sensitivity to Pore-Fluid Chemistry

KAUST Repository

Jang, Junbong; Santamarina, Carlos

2015-01-01

The 75-μm particle size is used to discriminate between fine and coarse grains. Further analysis of fine grains is typically based on the plasticity chart. Whereas pore-fluid-chemistry-dependent soil response is a salient and distinguishing

The Contribution of Outdoor Recreation and Outdoor Education to the Economy of Scotland: Case Studies and Preliminary Findings.

Science.gov (United States)

Higgins, Peter

2000-01-01

Outdoor recreation and education contribute substantially to the Scottish economy. Outdoor recreation generates considerable tourism income, much of it in rural areas, and also extends the traditional tourist season. Outdoor education centers are significant employers in certain rural areas. In addition, "therapeutic" outdoor programs…

Derivation of the fine-structure constant

International Nuclear Information System (INIS)

Samec, A.

1980-01-01

The fine-structure constant is derived as a dynamical property of quantum electrodynamics. Single-particle solutions of the coupled Maxwell and Dirac equations have a physical charge spectrum. The solutions are used to construct lepton-and quark-like particles. The strong, weak, electromagnetic, and gravitational forces are described as the interactions of complex charges in multiple combinations

The aggregation efficiency of very fine volcanic ash

Science.gov (United States)

Del Bello, E.; Taddeucci, J.; Scarlato, P.

2013-12-01

Explosive volcanic eruptions can discharge large amounts of very small sized pyroclasts (under 0.090 mm) into the atmosphere that may cause problems to people, infrastructures and environment. The transport and deposition of fine ash are ruled by aggregation that causes premature settling of fine ash and, as consequence, significantly reduces the concentration of airborne material over long distances. Parameterizing the aggregation potential of fine ash is then needed to provide accurate modelling of ash transport and deposition from volcanic plumes. Here we present the first results of laboratory experiments investigating the aggregation efficiency of very fine volcanic particles. Previous laboratory experiments have shown that collision kinetic and relative humidity provide the strongest effect on aggregation behaviour but were only limited to particles with size > 0.125 mm. In our work, we focus on natural volcanic ash at ambient humidity with particles size aggregation potential. Two types of ash were used in our experiments: fresh ash, collected during fall-out from a recent plume-forming eruption at Sakurajima (Japan -July 2013) and old ash, collected from fall-out tephra deposits at Campi Flegrei (Italy, ca. 10 ka), to account for the different chemical composition and morphoscopic effects of altered ash on aggregation efficiency. Total samples were hand sieved to obtain three classes with unimodal grain size distributions (sieved from the top of a transparent tank where a fan, placed at the bottom, allows turbulent dispersion of particles. Collision and sticking of particles on a vertical glass slide were filmed with a high speed cameras at 6000 fps. Our lenses arrangement provide high image resolution allowing to capture particles down to 0.005 mm in diameter. Video sequences of particles motion and collision were then processed with image analysis and particle tracking tools to determine i) the particle number density and ii) the grain size distribution

Predicting outdoor sound

CERN Document Server

Attenborough, Keith; Horoshenkov, Kirill

2014-01-01

1. Introduction  2. The Propagation of Sound Near Ground Surfaces in a Homogeneous Medium  3. Predicting the Acoustical Properties of Outdoor Ground Surfaces  4. Measurements of the Acoustical Properties of Ground Surfaces and Comparisons with Models  5. Predicting Effects of Source Characteristics on Outdoor Sound  6. Predictions, Approximations and Empirical Results for Ground Effect Excluding Meteorological Effects  7. Influence of Source Motion on Ground Effect and Diffraction  8. Predicting Effects of Mixed Impedance Ground  9. Predicting the Performance of Outdoor Noise Barriers  10. Predicting Effects of Vegetation, Trees and Turbulence  11. Analytical Approximations including Ground Effect, Refraction and Turbulence  12. Prediction Schemes  13. Predicting Sound in an Urban Environment.

Health Benefits of Particle Filtration

Energy Technology Data Exchange (ETDEWEB)

Fisk, William J.

2013-10-01

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percent age improvement in health outcomes is typically modest, for example, 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

Health Benefits of Particle Filtration

Energy Technology Data Exchange (ETDEWEB)

Fisk, William J.

2013-10-01

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, e.g., 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

A 2D Micromodel Study of Fines Migration and Clogging Behavior in Porous Media: Implications of Fines on Methane Extraction from Hydrate-Bearing Sediments

Science.gov (United States)

Cao, S. C.; Jang, J.; Waite, W. F.; Jafari, M.; Jung, J.

2017-12-01

Fine-grained sediment, or "fines," exist nearly ubiquitously in natural sediment, even in the predominantly coarse-grained sediments that host gas hydrates. Fines within these sandy sediments can play a crucial role during gas hydrate production activities. During methane extraction, several processes can alter the mobility and clogging potential of fines: 1) fluid flow as the formation is depressurized to release methane from hydrate; 2) pore-fluid chemistry shifts as pore-fluid brine freshens due to pure water released from dissociating hydrate; 3) the presence of a moving gas/water interface as gas evolves from dissociating hydrate and moves through the reservoir toward the production well. To evaluate fines migration and clogging behavior changes resulting from methane gas production and pore-water freshening during hydrate dissociation, 2D micromodel experiments have been conducted on a selection of pure fines, pore-fluids, and micromodel pore-throat sizes. Additionally, tests have been run with and without an invading gas phase (CO2) to test the significance of a moving meniscus on fines mobility and clogging. The endmember fine particles chosen for this research include silica silt, mica, calcium carbonate, diatoms, kaolinite, illite, and bentonite (primarily made of montmorillonite). The pore fluids include deionized water, sodium chloride brine (2M concentration), and kerosene. The microfluidic pore models, used as porous media analogs, were fabricated with pore-throat widths of 40, 60, and 100 µm. Results from this research show that in addition to the expected dependence of clogging on the ratio of particle-to-pore-throat size, pore-fluid chemistry is also a significant factor because the interaction between a particular type of fine and pore fluid influences that fine's capacity to cluster, clump together and effectively increase its particle "size" relative to the pore-throat width. The presence of a moving gas/fluid meniscus increases the clogging

Aerosol particles generated by diesel-powered school buses at urban schools as a source of children's exposure.

Science.gov (United States)

Hochstetler, Heather A; Yermakov, Mikhail; Reponen, Tiina; Ryan, Patrick H; Grinshpun, Sergey A

2011-03-01

Various heath effects in children have been associated with exposure to traffic-related particulate matter (PM), including emissions from school buses. In this study, the indoor and outdoor aerosol at four urban elementary schools serviced by diesel-powered school buses was characterized with respect to the particle number concentrations and size distributions as well as the PM2.5 mass concentrations and elemental compositions. It was determined that the presence of school buses significantly affected the outdoor particle size distribution, specifically in the ultrafine fraction. The time-weighted average of the total number concentration measured outside the schools was significantly associated with the bus and the car counts. The concentration increase was consistently observed during the morning drop-off hours and in most of the days during the afternoon pick-up period (although at a lower degree). Outdoor PM2.5 mass concentrations measured at schools ranged from 3.8 to 27.6 µg m -3 . The school with the highest number of operating buses exhibited the highest average PM2.5 mass concentration. The outdoor mass concentrations of elemental carbon (EC) and organic carbon (OC) were also highest at the school with the greatest number of buses. Most (47/55) correlations between traffic-related elements identified in the outdoor PM2.5 were significant with elements identified in the indoor PM2.5. Significant associations were observed between indoor and outdoor aerosols for EC, EC/OC, and the total particle number concentration. Day-to-day and school-to-school variations in Indoor/Outdoor (I/O) ratios were related to the observed differences in opening windows and doors, which enhanced the particle penetration, as well as indoor activities at schools. Overall, the results on I/O ratio obtained in this study reflect the sizes of particles emitted by diesel-powered school bus engines (primarily, an ultrafine fraction capable of penetrating indoors).

Effects of Temperature and Residence Time on the Emissions of PIC and Fine Particles during Fixed Bed Combustion of Conifer Stemwood Pellets

Energy Technology Data Exchange (ETDEWEB)

Boman, Christoffer; Lindmark, Fredrik; Oehman, Marcus; Nordin, Anders [Umeaa Univ. (Sweden). Energy Technology and Thermal Process Chemistry; Pettersson, Esbjoern [Energy Technology Centre, Piteaa (Sweden); Westerholm, Roger [Stockholm Univ., Arrhenius Laboratory (Sweden). Dept. of Analytical Chemistry

2006-07-15

The use of wood fuel Pellets has proved to be well suited for the small-scale market enabling controlled and efficient combustion with low emission of products of incomplete combustion (PIC). Still a potential for further emission reduction exists and a thorough understanding of the influence of combustion conditions on the emission characteristics of air pollutants like PAH and particulate matter (PM) is important. The objective was to determine the effects of temperature and residence time on the emission performance and characteristics with focus on hydrocarbons and PM during combustion of conifer stemwood Pellets in a laboratory fixed bed reactor (<5 kW). Temperature and residence time after the bed section were varied according to statistical experimental designs (650-970 deg C and 0.5-3.5 s) with the emission responses; CO, organic gaseous carbon, NO, 20 VOC compounds, 43 PAH compounds, PM{sub tot}, fine particle mass/count median diameter (MMD and CMD) and number concentration. Temperature was negatively correlated with the emissions of all studied PIC with limited effects of residence time. The PM{sub tot} emissions of 15-20 mg/MJ was in all cases dominated by fine (<1 {mu}m) particles of K, Na, S, Cl, C, O and Zn. Increased residence time resulted in increased fine particle sizes (i.e. MMD and CMD) and decreased number concentrations. The importance of high temperature (>850 deg C) in the bed zone with intensive, air rich and well mixed isothermal conditions for 0.5-1.0 s in the post combustion zone was illustrated for wood Pellets combustion with almost a total depletion of all studied PIC. The results emphasize the need for further verification studies and technology development work.

Trajectory calculation of a trapped particle in electro-dynamic balance for study of chemical reaction of aerosol particles

International Nuclear Information System (INIS)

Okuma, Miho; Itou, Takahiro; Harano, Azuchi; Takarada, Takayuki; James, Davis E

2013-01-01

Electrodynamic balance (EDB) is a powerful tool for investigating the chemical reactions between a fine particle and gaseous species. But the EDB device alone is inadequate to match the rapid weight change of a fine particle caused by chemical reactions, because it takes a few seconds to set a fine particle at null point. The particle trajectory calculation for the trapped particle added to the EDB is thus a very useful tool for the measurement of the transient response of a particle weight change with no need to adjust the applied DC voltage to set the null point. The purpose of this study is to develop the trajectory calculation method to track the particle oscillation pattern in the EDB and examine the possibility for kinetic studies on the reaction of a single aerosol particle with gaseous species. The results demonstrated the feasibility of applying particle trajectory calculation to realize the research purpose.

Chemical characterization and sources of personal exposure to fine particulate matter in the general population of Guangzhou, China

Science.gov (United States)

Chen, Xiao-Cui; Jahn, Heiko J.; Engling, Guenter; Ward, Tony J.; Kraemer, Alexander; Ho, Kin-Fai; Hung-Lam Yim, Steve; Chan, Chuen-Yu

2017-04-01

Fine particulate matter pollution severely deteriorates the environmental conditions and negatively impacts human health in the Chinese megacity Guangzhou. Concurrent ambient and personal measurements of fine particulate matter (PM2.5) were conducted in Guangzhou, China. Personal-to-ambient (P-C) relationships of PM2.5 chemical components were determined and sources of personal PM2.5 exposure were evaluated using principal component analysis along with a mixed-effects model. Water-soluble inorganic ions (mainly secondary inorganic ions) and anhydrosugars exhibited median personal-to-ambient (P/C) ratios < 1 accompanied by strong P-C correlations, indicating that these constituents in personal PM2.5 were significantly affected by ambient sources. Conversely, elemental carbon (EC) and calcium (Ca2+) showed median P/C ratios greater than unity, which indicated that among subjects who spent a great amount of time indoors, aside from particles of ambient origin, individual's total exposure to PM2.5 includes contributions of non-ambient exposure while indoors and outdoors (e.g., local traffic, indoor sources, personal activities). SO42- displayed very low coefficient of divergence (COD) values coupled with strong P-C correlations, implying a uniform distribution of SO42- in the urban area of Guangzhou. EC, Ca2+, and levoglucosan were otherwise heterogeneously distributed across individuals in different districts. Regional air pollution (50.4 ± 0.9%), traffic-related particles (8.6 ± 0.7%), dust-related particles (5.8 ± 0.7%), and biomass burning emissions (2.0 ± 0.2%) were moderate to high positive sources of personal PM2.5 exposure in Guangzhou. The observed positive and significant contribution of Ca2+ to personal PM2.5 exposure, highlighting indoor sources and/or personal activities, were driving factors determining personal exposure to dust-related particles. Considerable discrepancies (COD values ranging from 0.42 to 0.50) were shown between ambient

Indoor and Outdoor Exposure to Ultrafine, Fine and Microbiologically Derived Particulate Matter Related to Cardiovascular and Respiratory Effects in a Panel of Elderly Urban Citizens

DEFF Research Database (Denmark)

Karottki, Dorina Gabriela; Spilak, Michal; Frederiksen, Marie

2015-01-01

), lung function, blood leukocyte counts, monocyte adhesion molecule expression, C-reactive protein, Clara cell protein (CC16) and surfactant protein-D (SPD) were examined in relation to exposure preceding each measurement. Exposure assessment included 48-h urban background monitoring of PM10, PM2.......5 and particle number concentration (PNC), weekly measurements of PM2.5 in living- and bedroom, 24-h measurements of indoor PNC three times, and bio-aerosol components in settled dust on a 2-week basis. Statistically significant inverse associations included: MVF with outdoor PNC; granulocyte counts with PM2.......5; CD31 expression with dust fungi; SPD with dust endotoxin. Significant positive associations included: MVF with dust bacteria; monocyte expression of CD11 with PM2.5 in the bedroom and dust bacteria and endotoxin, CD31 expression with dust serine protease; serum CC16 with dust NAGase. Multiple...

Vertical profiles of fine and coarse aerosol particles over Cyprus: Comparison between in-situ drone measurements and remote sensing observations

Science.gov (United States)

Mamali, Dimitra; Marinou, Eleni; Pikridas, Michael; Kottas, Michael; Binietoglou, Ioannis; Kokkalis, Panagiotis; Tsekeri, Aleksandra; Amiridis, Vasilis; Sciare, Jean; Keleshis, Christos; Engelmann, Ronny; Ansmann, Albert; Russchenberg, Herman W. J.; Biskos, George

2017-04-01

Vertical profiles of the aerosol mass concentration derived from light detection and ranging (lidar) measurements were compared to airborne dried optical particle counter (OPC MetOne; Model 212) measurements during the INUIT-BACCHUS-ACTRIS campaign. The campaign took place in April 2016 and its main focus was the study of aerosol dust particles. During the campaign the NOA Polly-XT Raman lidar located at Nicosia (35.08° N, 33.22° E) was providing round-the-clock vertical profiles of aerosol optical properties. In addition, an unmanned aerial vehicle (UAV) carrying an OPC flew on 7 days during the first morning hours. The flights were performed at Orounda (35.1018° N, 33.0944° E) reaching altitudes of 2.5 km a.s.l, which allows comparison with a good fraction of the recorded lidar data. The polarization lidar photometer networking method (POLIPHON) was used for the estimation of the fine (non-dust) and coarse (dust) mode aerosol mass concentration profiles. This method uses as input the particle backscatter coefficient and the particle depolarization profiles of the lidar at 532 nm wavelength and derives the aerosol mass concentration. The first step in this approach makes use of the lidar observations to separate the backscatter and extinction contributions of the weakly depolarizing non-dust aerosol components from the contributions of the strongly depolarizing dust particles, under the assumption of an externally mixed two-component aerosol. In the second step, sun photometer retrievals of the fine and the coarse modes aerosol optical thickness (AOT) and volume concentration are used to calculate the associated concentrations from the extinction coefficients retrieved from the lidar. The estimated aerosol volume concentrations were converted into mass concentration with an assumption for the bulk aerosol density, and compared with the OPC measurements. The first results show agreement within the experimental uncertainty. This project received funding from the

Formal education in outdoor studies: introduction

OpenAIRE

Prince, Heather

2015-01-01

Regional cultural perspectives involve outdoor studies in different ways in formal curricula. This section focuses on Western Europe, particularly the UK and Scandinavia, although also has a more international reach in Backman’s consideration of the training of teachers and in place-responsive teaching as described by Mannion and Lynch. ‘Outdoor studies’ is not seen in curricula per se but under various more specialised aspects such as outdoor play, outdoor learning, environmental education, ...

The Cost of Becoming an Outdoor Instructor.

Science.gov (United States)

Cashel, Chris

This article describes instructor criteria in three outdoor organizations: Outward Bound (OB), the National Outdoor Leadership School (NOLS), and the Wilderness Education Association (WEA). Common requirements for outdoor leadership programs are outdoor experience and skills, advanced first aid, CPR, and a minimum age requirement. Traditionally…

Reprint of: A numerical investigation of fine sediment resuspension in the wave boundary layer-Uncertainties in particle inertia and hindered settling

Science.gov (United States)

Cheng, Zhen; Yu, Xiao; Hsu, Tian-Jian; Balachandar, S.

2016-05-01

The wave bottom boundary layer is a major conduit delivering fine terrestrial sediments to continental margins. Hence, studying fine sediment resuspensions in the wave boundary layer is crucial to the understanding of various components of the earth system, such as carbon cycles. By assuming the settling velocity to be a constant in each simulation, previous turbulence-resolving numerical simulations reveal the existence of three transport modes in the wave boundary layer associated with sediment availabilities. As the sediment availability and hence the sediment-induced stable stratification increases, a sequence of transport modes, namely, (I) well-mixed transport, (II) formulation of lutocline resembling a two-layer system, and (III) completely laminarized transport are observed. In general, the settling velocity is a flow variable due to hindered settling and particle inertia effects. Present numerical simulations including the particle inertia suggest that for a typical wave condition in continental shelves, the effect of particle inertia is negligible. Through additional numerical experiments, we also confirm that the particle inertia tends (up to the Stokes number St = 0.2) to attenuate flow turbulence. On the other hand, for flocs with lower gelling concentrations, the hindered settling can play a key role in sustaining a large amount of suspended sediments and results in the laminarized transport (III). For the simulation with a very significant hindered settling effect due to a low gelling concentration, results also indicate the occurrence of gelling ignition, a state in which the erosion rate is always higher than the deposition rate. A sufficient condition for the occurrence of gelling ignition is hypothesized for a range of wave intensities as a function of sediment/floc properties and erodibility parameters.

Curriculum Development in Outdoor Education: Tasmanian Teachers' Perspectives on the New Pre-Tertiary Outdoor Leadership Course

Science.gov (United States)

Dyment, Janet; Morse, Marcus; Shaw, Simon; Smith, Heidi

2014-01-01

The paper examines how outdoor education teachers in Tasmania, Australia have implemented and perceive a new pre-tertiary Outdoor Leadership curriculum document. It draws on an analysis of in-depth semi-structured interviews with 11 outdoor education teachers. The results revealed that teachers were generally welcoming of the new higher-order…

Numerical simulation of fine oil sand tailings drying in test cells

NARCIS (Netherlands)

Vardon, P.J.; Nijssen, T.; Yao, Y.; Van Tol, A.F.

2014-01-01

As a promising technology in disposal of mature fine tailings (MFT), atmospheric fines drying (AFD) is currently being implemented on a commercial scale at Shell Canada’s Muskeg River Mine near Fort McMurray, Alberta. AFD involves the use of a polymer flocculent to bind fine particles in MFT

Fine particle pH and gas-particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign

Science.gov (United States)

Guo, Hongyu; Liu, Jiumeng; Froyd, Karl D.; Roberts, James M.; Veres, Patrick R.; Hayes, Patrick L.; Jimenez, Jose L.; Nenes, Athanasios; Weber, Rodney J.

2017-05-01

pH is a fundamental aerosol property that affects ambient particle concentration and composition, linking pH to all aerosol environmental impacts. Here, PM1 and PM2. 5 pH are calculated based on data from measurements during the California Research at the Nexus of Air Quality and Climate Change (CalNex) study from 15 May to 15 June 2010 in Pasadena, CA. Particle pH and water were predicted with the ISORROPIA-II thermodynamic model and validated by comparing predicted to measured gas-particle partitioning of inorganic nitrate, ammonium, and chloride. The study mean ± standard deviation PM1 pH was 1.9 ± 0.5 for the SO42--NO3--NH4+-HNO3-NH3 system. For PM2. 5, internal mixing of sea salt components (SO42--NO3--NH4+-Na+-Cl--K+-HNO3-NH3-HCl system) raised the bulk pH to 2.7 ± 0.3 and improved predicted nitric acid partitioning with PM2. 5 components. The results show little effect of sea salt on PM1 pH, but significant effects on PM2. 5 pH. A mean PM1 pH of 1.9 at Pasadena was approximately one unit higher than what we have reported in the southeastern US, despite similar temperature, relative humidity, and sulfate ranges, and is due to higher total nitrate concentrations (nitric acid plus nitrate) relative to sulfate, a situation where particle water is affected by semi-volatile nitrate concentrations. Under these conditions nitric acid partitioning can further promote nitrate formation by increasing aerosol water, which raises pH by dilution, further increasing nitric acid partitioning and resulting in a significant increase in fine particle nitrate and pH. This study provides insights into the complex interactions between particle pH and nitrate in a summertime coastal environment and a contrast to recently reported pH in the eastern US in summer and winter and the eastern Mediterranean. All studies have consistently found highly acidic PM1 with pH generally below 3.

Impact of Middle Eastern dust storms on indoor and outdoor composition of bioaerosol

Science.gov (United States)

Soleimani, Zahra; Goudarzi, Gholamreza; Sorooshian, Armin; Marzouni, Mohammad Bagherian; Maleki, Heidar

2016-08-01

The presence of microbes in airborne aerosol particles, especially dust, is a major public health concern in desert regions. This study is the first of its kind to examine the effect of dust storms on indoor and outdoor microbial air quality at a hospital on the western side of Iran (city of Ahvaz), which is notorious for being highly vulnerable to dust emissions. Air samples were collected inside and outside of the hospital environment for six months, with the unique advantage of this study being that the region and duration of measurements allow for a clear comparison between dusty and normal days. On normal days, the average concentrations (outdoor/indoor) of bacteria and fungi were 423/329 cfu m-3 and 596/386 cfu m-3, respectively, which increased to 1257/406 cfu m-3 and 1116/550 cfu m-3 on dust event days. Indoor/Outdoor ratios for bacteria and fungi are lower on dust event days (0.26-0.60) versus normal days (0.44-0.95). Bacillus spp., Micrococcus spp., Streptomyces spp., and Staphylococcus spp. were the dominant bacteria both indoors and outdoors on normal and dust event days. Gram positive bacteria exhibited higher concentrations than Gram negative bacteria in both outdoor and indoor air samples as well as during both normal and dust event days. The data suggest that Gram positive bacteria are more resistant to undesirable outdoor conditions (e.g., high incident solar radiation) as compared to Gram negative ones. These results have implications for other populated arid regions where more stringent control of indoor air quality can greatly benefit public health.

Outdoor schools: Limits and dilemmas

Directory of Open Access Journals (Sweden)

Irena Smetáčková

2011-12-01

Full Text Available Outdoor school is a stable element of Czech educational system. However,many changes have occurred during the last twenty years in the purposes of outdoorschools and in their organization. The article presents various school statistics andresults of research which included questionnaire survey in elementary schools in Pragueand a case study of two classes. The study found that the outdoor school programmesare getting shorter, budgets for outdoor schools are reduced, and prices of outdoorschool programmes for parents are increasing. Because of high prices, almost 20 % ofpupils cannot attend outdoor schools. Nevertheless, according to teachers, pupils andparents, the main purpose of outdoor school programmes is to create a better socialclimate in peer groups. Because of high rates of absence, this goal is partly invalid.Another purpose should be that teachers and children get to know each other better.This goal is invalid as well because many schools hire commercial agencies which limitsthe time that pupils and teachers spend together.

Element determination of fine particles in environmental aerosols using PIXE

International Nuclear Information System (INIS)

Garcia O, B.; Aldape U, F.

2007-01-01

The Mexico city is classified as one of the more populated cities of the world which presents a decrease in the air quality and that gives place to a severe problematic in atmospheric pollution. To cooperate in the solution of this problem it is necessary to carry out studies that allow a better knowledge of the atmosphere of the city. This study presents the results of a monitoring campaign of fine particle carried out from September 21 to December 12, 2001 in three sites of the Mexico City center area. The samples were collected every third day with a collector type unit of heaped filters (Gent). The analysis of these samples was carried out in the 2 MV accelerator of the National Institute of Nuclear Research (ININ) applying the PIXE technique and with this analysis its were identified in the samples approximately 15 elements in each one of the 3 sites and was calculated the concentration in that its were present. With these results a database was created and by means of it mathematical treatment the Enrichment factor (FE), the time series of each element and the multiple correlation matrix were evaluated. The obtained results showed that the Civil Registration site (Salto del Agua) it was the more polluted coinciding that to a bigger concentration of activities a bigger increase in the pollution is generated. (Author)

Regulatory T Cells Protect Fine Particulate Matter-Induced Inflammatory Responses in Human Umbilical Vein Endothelial Cells

Directory of Open Access Journals (Sweden)

Wen-cai Zhang

2014-01-01

Full Text Available Objective. To investigate the role of CD4+CD25+ T cells (Tregs in protecting fine particulate matter (PM- induced inflammatory responses, and its potential mechanisms. Methods. Human umbilical vein endothelial cells (HUVECs were treated with graded concentrations (2, 5, 10, 20, and 40 µg/cm2 of suspension of fine particles for 24h. For coculture experiment, HUVECs were incubated alone, with CD4+CD25− T cells (Teff, or with Tregs in the presence of anti-CD3 monoclonal antibodies for 48 hours, and then were stimulated with or without suspension of fine particles for 24 hours. The expression of adhesion molecules and inflammatory cytokines was examined. Results. Adhesion molecules, including vascular cell adhesion molecule-1 (VCAM-1 and intercellular adhesion molecule-1 (ICAM-1, and inflammatory cytokines, such as interleukin (IL- 6 and IL-8, were increased in a concentration-dependent manner. Moreover, the adhesion of human acute monocytic leukemia cells (THP-1 to endothelial cells was increased and NF-κB activity was upregulated in HUVECs after treatment with fine particles. However, after Tregs treatment, fine particles-induced inflammatory responses and NF-κB activation were significantly alleviated. Transwell experiments showed that Treg-mediated suppression of HUVECs inflammatory responses impaired by fine particles required cell contact and soluble factors. Conclusions. Tregs could attenuate fine particles-induced inflammatory responses and NF-κB activation in HUVECs.

Definition: Conservation Education, Environmental Education, Outdoor Education.

Science.gov (United States)

1970

Conservation education, outdoor education, and environmental education all have as a common goal the understanding and appreciation of the natural world. Outdoor education is a method of teaching wherein established disciplines, topics, and concepts which can best be taught outdoors are taught outdoors. Conservation education is the study of man's…

Exposure to secondhand smoke in terraces and other outdoor areas of hospitality venues in eight European countries.

Science.gov (United States)

López, Maria J; Fernández, Esteve; Gorini, Giuseppe; Moshammer, Hanns; Polanska, Kinga; Clancy, Luke; Dautzenberg, Bertrand; Delrieu, Agnes; Invernizzi, Giovanni; Muñoz, Glòria; Precioso, Jose; Ruprecht, Ario; Stansty, Peter; Hanke, Wojciech; Nebot, Manel

2012-01-01

Outdoor secondhand smoke (SHS) concentrations are usually lower than indoor concentrations, yet some studies have shown that outdoor SHS levels could be comparable to indoor levels under specific conditions. The main objectives of this study were to assess levels of SHS exposure in terraces and other outdoor areas of hospitality venues and to evaluate their potential displacement to adjacent indoor areas. Nicotine and respirable particles (PM2.5) were measured in outdoor and indoor areas of hospitality venues of 8 European countries. Hospitality venues of the study included night bars, restaurants and bars. The fieldwork was carried out between March 2009 and March 2011. We gathered 170 nicotine and 142 PM2.5 measurements during the study. The median indoor SHS concentration was significantly higher in venues where smoking was allowed (nicotine 3.69 µg/m3, PM2.5: 120.51 µg/m3) than in those where smoking was banned (nicotine: 0.48 µg/m3, PM2.5: 36.90 µg/m3). The median outdoor nicotine concentration was higher in places where indoor smoking was banned (1.56 µg/m3) than in venues where smoking was allowed (0.31 µg/m3). Among the different types of outdoor areas, the highest median outdoor SHS levels (nicotine: 4.23 µg/m3, PM2.5: 43.64 µg/m3) were found in the semi-closed outdoor areas of venues where indoor smoking was banned. Banning indoor smoking seems to displace SHS exposure to adjacent outdoor areas. Furthermore, indoor settings where smoking is banned but which have a semi-closed outdoor area have higher levels of SHS than those with open outdoor areas, possibly indicating that SHS also drifts from outdoors to indoors. Current legislation restricting indoor SHS levels seems to be insufficient to protect hospitality workers--and patrons--from SHS exposure. Tobacco-free legislation should take these results into account and consider restrictions in the terraces of some hospitality venues to ensure effective protection.

Light extinction by fine atmospheric particles in the White Mountains region of New Hampshire and its relationship to air mass transport.

Science.gov (United States)

Slater, John F; Dibb, Jack E; Keim, Barry D; Talbot, Robert W

2002-03-27

Chemical, optical, and physical measurements of fine aerosols (aerodynamic diameter mass origin. Filter-based, 24-h integrated samples were collected and analyzed for major inorganic ions, as well as organic (OC), elemental (EC), and total carbon. Light scattering and light absorption coefficients were measured at 5-min intervals using an integrating nephelometer and a light absorption photometer. Fine particle number density was measured with a condensation particle counter. Air mass origins and transport patterns were investigated through the use of 3-day backward trajectories and a synoptic climate classification system. Two distinct transport regimes were observed: (1) flow from the north/northeast (N/NE) occurred during 9 out of 18 sample-days; and (2) flow from the west/southwest (W/SW) occurred 8 out of 18 sample-days. All measured and derived aerosol and meteorological parameters were separated into two categories based on these different flow scenarios. During W/SW flow, higher values of aerosol chemical concentration, absorption and scattering coefficients, number density, and haziness were observed compared to N/NE flow. The highest level of haziness was associated with the climate classification Frontal Atlantic Return, which brought polluted air into the region from the mid-Atlantic corridor. Fine particle mass scattering efficiencies of (NH4)2SO4 and OC were 5.35 +/- 0.42 m2 g(-1) and 1.56 +/- 0.40 m2 g(-1), respectively, when transport was out of the N/NE. When transport was from the W/SW the values were 4.94 +/- 0.68 m2 g(-1) for (NH4)2SO4 and 2.18 +/- 0.91 m2 g(-1) for OC. EC mass absorption efficiency when transport was from the N/NE was 9.66 +/- 1.06 m2 g(-1) and 10.80 +/- 1.76 m2 g(-1) when transport was from the W/SW. Results from this work can be used to predict visual air quality in the White Mountain National Forest based on a forecasted synoptic climate classification and its associated visibility.

Computational Fluid-Particle Dynamics for the Flame Synthesis of Alumina Particles

DEFF Research Database (Denmark)

Johannessen, Tue; Pratsinis, Sotirie E.; Livbjerg, Hans

2000-01-01

A mathematical model for the dynamics of particle growth during synthesis of ultra fine particles in diffusion flames is presented. The model includes the kinetics of particle coalescence and coagulation, and when combined with a calculation of the temperature, velocity and gas composition distri...

Definitions of Outdoor Recreation and Other Associated Terminology.

Science.gov (United States)

Phipps, Maurice L.

This document defines terms related to outdoor recreation: (1) outdoor recreation includes activities that occur outdoors in an urban and man-made environment as well as those activities traditionally associated with the natural environment; (2) outdoor education is education in, about, and for the outdoors; (3) environmental education is an…

Outdoor Leadership Skills: A Program Perspective

Science.gov (United States)

Shooter, Wynn; Sibthorp, Jim; Paisley, Karen

2009-01-01

Successful hiring, training, and pairing or grouping of staff requires administrators to consider the relationship between their programs' goals and the specific outdoor leadership skills of individual leaders. Authors have divided outdoor leadership skills into a three-category structure, and models of outdoor leadership have focused on skills…

Cleaning and dewatering fine coal

Science.gov (United States)

Yoon, Roe-Hoan; Eraydin, Mert K.; Freeland, Chad

2017-10-17

Fine coal is cleaned of its mineral matter impurities and dewatered by mixing the aqueous slurry containing both with a hydrophobic liquid, subjecting the mixture to a phase separation. The resulting hydrophobic liquid phase contains coal particles free of surface moisture and droplets of water stabilized by coal particles, while the aqueous phase contains the mineral matter. By separating the entrained water droplets from the coal particles mechanically, a clean coal product of substantially reduced mineral matter and moisture contents is obtained. The spent hydrophobic liquid is separated from the clean coal product and recycled. The process can also be used to separate one type of hydrophilic particles from another by selectively hydrophobizing one.

The Dirt on Outdoor Classrooms.

Science.gov (United States)

Rich, Steve

2000-01-01

Explains the planning procedure for outdoor classrooms and introduces an integrated unit on monarch butterflies called the Monarch Watch program. Makes recommendations to solve financial problems of outdoor classrooms. (YDS)

9 CFR 3.52 - Facilities, outdoor.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Facilities, outdoor. 3.52 Section 3.52 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL... outdoors when the atmospheric temperature falls below 40 °F. (d) Protection from predators. Outdoor housing...

Characterization of short- and medium-chain chlorinated paraffins in outdoor/indoor PM10/PM2.5/PM1.0 in Beijing, China.

Science.gov (United States)

Huang, Huiting; Gao, Lirong; Xia, Dan; Qiao, Lin; Wang, Runhua; Su, Guijin; Liu, Wenbin; Liu, Guorui; Zheng, Minghui

2017-06-01

Persistent organic pollutants (POPs) were listed in the Stockholm Convention, because of their adverse health effects, persistence, bioaccumulation and ubiquitous presence in the environment. Short chain chlorinated paraffins (SCCPs), chlorinated derivatives of n-alkanes, have been listed as candidate POPs under Stockholm Convention. Inhalation uptake was an important exposure pathway for non-occupational adult human and the pollution of particle matter has caused great concern. There are some studies focused on POPs such as polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans and polybrominated diphenyl ethers in different size particles. However, there were no studies that discussed CP concentrations in particulate matter (PM) with different sizes. In this study, a total of 30 PM samples were collected both outdoors and indoors at a sampling site in Beijing. These samples were used to investigate the concentrations and distributions of SCCPs and medium chain chlorinated paraffins (MCCPs) in PM fractions of different sizes, and to evaluate inhalation exposure risks. The results showed that the average SCCPs and MCCPs in the outdoor PM 10 were 23.9 and 3.6 ng m -3 , while the mean values in indoor were 61.1 and 6.9 ng m -3 , respectively. The levels of SCCPs and MCCPs in indoor and outdoor were relatively high. SCCP and MCCP concentrations in the indoor PM 10 /PM 2.5 /PM 1.0 samples were higher than the corresponding values in the outdoor, because of the using of some products containing CPs in the indoors, like paints and coatings, leather and rubber products. In both outdoor and indoor air, CPs are mainly associated with particles ≤2.5 μm in diameter. The main homolog groups for both SCCPs and MCCPs were C 10-11 Cl 7-8 . It is assumed that SCCPs in the outdoor and indoor PM samples may mainly derive from the production and use of CP-42 and CP-52. Copyright © 2017 Elsevier Ltd. All rights reserved.

Health benefits of particle filtration.

Science.gov (United States)

Fisk, W J

2013-10-01

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, for example, 7% to 25%. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air. Published 2013. This article is a US Government work and is in the public domain in the USA.

Single-particle effects in fine structure of super-asymmetric fission

International Nuclear Information System (INIS)

Mirea, M.

1999-01-01

Energy spectrum measurements concerning the 14 C decay from 223 Ra revealed a fine structure with an intense branch on the excited state of the daughter 209 Pb. Apart the great number of microscopic--macroscopic attempts of different authors in describing this behavior (compiled recently), this phenomenon was explained quantitatively using the Landau--Zener effect, i.e., the promotion mechanism of a unpaired nucleon between two levels characterised by the same quantum numbers connected to some symmetries of the nuclear system in the region where an avoided level crossing is exhibited. The adiabatic levels during the super-asymmetric fission process were determined with a new version of the two--centre shell model especially constructed for very large mass--asymmetries. The half--lives are obtained in the framework of the Wentzel--Kramers--Brillouin approximation. The amount of the variation of the barrier height in the excited channels was estimated accounting the specialization energy which can be interpreted as the excess of the energy of a nucleon with a given spin over the energy for the same spin nucleon state of lowest energy. It is evidenced that the fine structure of cluster decay is due to two competitive effects: the Landau--Zener effect which enhances the probability to have an excited daughter in the final channel and the specialization energy which increases the potential barrier and therefore leads to a diminution of the penetrability. This formalism was used for predictions of the fine structure in the case of 14 C decay of 225 Ac and to explain the fine structure of alpha decay. (author)

Bubbling behavior of a fluidized bed of fine particles caused by vibration-induced air inflow.

Science.gov (United States)

Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi

2013-01-01

We demonstrate that a vibration-induced air inflow can cause vigorous bubbling in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of bubbles that rise and eventually burst at the top surface of the powder bed. A negative pressure is created below the rising bubbles. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously bubbling fluidized bed that does not require the use of an external air supply system.

The study of anthropogenic fine particles transported from urban areas to rural and non-urban environments using nuclear related techniques

International Nuclear Information System (INIS)

Cohen, D.D.; Bailey, G.M.; Martin, J.W.; Crisp, P.T.

1994-01-01

Aerosol particles in the size range less than 2.5 μm play an important role in pollution studies. They are small enough to lodge in lungs and cause health problems, they impair visibility and the public's perception of pollution and they are capable of being transported over large distances as they do not settle out readily. In this report we will describe the large area fine particle network consisting of 25 cyclone sampling units covering 80,000 square kilometre of the state of New South Wales in Australia. The network called ASP-Air Sampling Program - collects particles on 25 mm stretched Teflon filter papers which are ideal targets for accelerator based Ion Beam Analysis (IBA). We will discuss the four IBA techniques, PIXE, PIGME, PESA and RBS used simultaneously on the accelerator at ANSTO and present some of the early results of the Co-operative Research Programme. (author). 7 refs, 8 figs, 1 tab

An evaluation of the impact of flooring types on exposures to fine and coarse particles within the residential micro-environment using CONTAM.

Science.gov (United States)

Bramwell, Lisa; Qian, Jing; Howard-Reed, Cynthia; Mondal, Sumona; Ferro, Andrea R

2016-01-01

Typical resuspension activities within the home, such as walking, have been estimated to contribute up to 25% of personal exposures to PM10. Chamber studies have shown that for moderate walking intensities, flooring type can impact the rate at which particles are re-entrained into the air. For this study, the impact of residential flooring type on incremental average daily (24 h) time-averaged exposure was investigated. Distributions of incremental time-averaged daily exposures to fine and coarse PM while walking within the residential micro-environment were predicted using CONTAM, the multizone airflow and contaminant transport program of the National Institute of Standards and Technology. Knowledge of when and where a person was walking was determined by randomly selecting 490 daily diaries from the EPA's consolidated human activity database (CHAD). On the basis of the results of this study, residential flooring type can significantly impact incremental time-averaged daily exposures to coarse and fine particles (α=0.05, P<0.05, N=490, Kruskal-Wallis test) with high-density cut pile carpeting resulting in the highest exposures. From this study, resuspension from walking within the residential micro-environment contributed 6-72% of time-averaged daily exposures to PM10.

Performance of japanese quails fed feeds containing different corn and limestone particle sizes

Directory of Open Access Journals (Sweden)

DA Berto

2007-09-01

Full Text Available This study aimed at evaluating performance and egg quality of Japanese quails fed feeds containing different corn and limestone particle sizes. A total number of 648 birds in the peak of production was distributed in a random complete block experimental design, using a 2x3 factorial arrangement (2 corn particle sizes and 3 limestone particle sizes. Birds were designated to one of two blocks, with six replicates of 18 birds each. Mean geometric diameter (MGD values used were 0.617mm and 0.723mm (corn fine and coarse particle sizes, respectively, and 0.361mm, 0.721mm, and 0.947mm (limestone fine, intermediate and coarse particle sizes, respectively. The following treatments were applied: T1: fine corn feed, with 100% fine limestone; T2: fine corn feed, with 50% fine limestone and 50% intermediate limestone; T3: fine corn feed, with 50% fine limestone and 50% coarse limestone; T4: coarse corn feed, with 100% fine limestone; T5: coarse corn feed, with 50% fine limestone and 50% intermediate limestone; T6: coarse corn feed, with 50% fine limestone and 50% coarse limestone. The experiment lasted 112 days, consisting of 4 cycles of 28 days. No significant interaction was observed among corn and limestone particle sizes for any of the analyzed parameters. There were no significant effects (p>0.05 of the tested corn particle sizes on quail performance or egg quality. There were significant (p<0.05 isolated effects of limestone particle size only on the percentage of cracked eggs, which was reduced when birds fed 50% coarse limestone (0.947mm and 50% fine limestone (0.361mm as compared to those fed 100% fine limestone. Therefore, the inclusion of 50% coarse limestone (0.947mm is recommended for quail egg production.

Let's Walk Outdoors! Self-Paced Walking Outdoors Improves Future Intention to Exercise in Women With Obesity.

Science.gov (United States)

Krinski, Kleverton; Machado, Daniel G S; Lirani, Luciana S; DaSilva, Sergio G; Costa, Eduardo C; Hardcastle, Sarah J; Elsangedy, Hassan M

2017-04-01

In order to examine whether environmental settings influence psychological and physiological responses of women with obesity during self-paced walking, 38 women performed two exercise sessions (treadmill and outdoors) for 30 min, where oxygen uptake, heart rate, ratings of perceived exertion, affect, attentional focus, enjoyment, and future intentions to walk were analyzed. Physiological responses were similar during both sessions. However, during outdoor exercise, participants displayed higher externally focused attention, positive affect, and lower ratings of perceived exertion, followed by greater enjoyment and future intention to participate in outdoor walking. The more externally focused attention predicted greater future intentions to participate in walking. Therefore, women with obesity self-selected an appropriate exercise intensity to improve fitness and health in both environmental settings. Also, self-paced outdoor walking presented improved psychological responses. Health care professionals should consider promoting outdoor forms of exercise to maximize psychological benefits and promote long-term adherence to a physically active lifestyle.

A Global Perspective of Fine Particulate Matter Pollution and Its Health Effects.

Science.gov (United States)

Mukherjee, Arideep; Agrawal, Madhoolika

Fine particulate matter (PM) in the ambient air is implicated in a variety of human health issues throughout the globe. Regulation of fine PM in the atmosphere requires information on the dimension of the problem with respect to variations in concentrations and sources. To understand the current status of fine particles in the atmosphere and their potential harmful health effects in different regions of the world this review article was prepared based on peer-reviewed scientific papers, scientific reports, and database from government organizations published after the year 2000 to evaluate the global scenario of the PM 2.5 (particles levels and exceedances of national and international standards were several times higher in Asian countries, while levels in Europe and USA were mostly well below the respective standards. Vehicular traffic has a significant influence on PM 2.5 levels in urban areas; followed by combustion activities (biomass, industrial, and waste burning) and road dust. In urban atmosphere, fine particles are mostly associated with different health effects with old aged people, pregnant women, and more so children being the most susceptible ones. Fine PM chemical constituents severely effect health due to their carcinogenic or mutagenic nature. Most of the research indicated an exceedance of fine PM level of the standards with a diverse array of health effects based on PM 2.5 chemical constituents. Emission reduction policies with epidemiological studies are needed to understand the benefits of sustainable control measures for fine PM mitigation.

EXPOSURE TO CONCENTRATED AMBIENT PARTICLES (CAPS): REVIEW

Science.gov (United States)

Epidemiologic studies support a participation of fine particulate matter (PM) with a diameter of 0.1 to 2.5 microm in the effects of air pollution particles on human health. The ambient fine particle concentrator is a recently developed technology that can enrich the mass of ambi...

Outdoor Air Quality Level Inference via Surveillance Cameras

Directory of Open Access Journals (Sweden)

Zheng Zhang

2016-01-01

Full Text Available Air pollution is a universal problem confronted by many developing countries. Because there are very few air quality monitoring stations in cities, it is difficult for people to know the exact air quality level anytime and anywhere. Fortunately, large amount of surveillance cameras have been deployed in the cities and can capture image densely and conveniently in the cities. In this case, this provides the possibility to utilize surveillance cameras as sensors to obtain data and predict the air quality level. To this end, we present a novel air quality level inference approach based on outdoor images. Firstly, we explore several features extracted from images as the robust representation for air quality prediction. Then, to effectively fuse these heterogeneous and complementary features, we adopt multikernel learning to learn an adaptive classifier for air quality level inference. In addition, to facilitate the research, we construct an Outdoor Air Quality Image Set (OAQIS dataset, which contains high quality registered and calibrated images with rich labels, that is, concentration of particles mass (PM, weather, temperature, humidity, and wind. Extensive experiments on the OAQIS dataset demonstrate the effectiveness of the proposed approach.

Production of talc nano sheets via fine grinding and sonication processes

International Nuclear Information System (INIS)

Samayamutthirian Palaniandy; Noorina Hidayu Jamil Khairun Azizi Mohd Azizli; Syed Fuad Saiyid Hashim; Hashim Hussin

2009-01-01

Fine grinding of high purity talc in jet mill at low grinding pressure was carried out by varying the feed rate and classifier rotational speed. These ground particles were sonicated in laboratory ultrasonic bath by varying the soniction period at five levels. The ground and sonicated particles were characterized in terms of particle size and particle size distribution. Mechanochemical and sonochemical effect of talc was determine via X-ray diffraction. Particle shape and surface texture of the ground and sonicated product was determined via scanning electron microscope and transmission electron microscope. The ground particle size exhibited particle size below 10 μm with narrow size distribution. The reduction of peak intensity in (002) plane indicated the layered structure has been distorted. The sonicated talc shows that the thickness of the talc particles after the sonication process is 20 nm but the lateral particle size still remains in micron range. The reduction of the XRD peak intensity for (002) plane and thickness of sonicated talc as shown in SEM and TEM micrographs proves that fine grinding and sonication process produces talc nano sheets. (author)

Aerosol particles generated by diesel-powered school buses at urban schools as a source of children’s exposure

Science.gov (United States)

Hochstetler, Heather A.; Yermakov, Mikhail; Reponen, Tiina; Ryan, Patrick H.; Grinshpun, Sergey A.

2015-01-01

Various heath effects in children have been associated with exposure to traffic-related particulate matter (PM), including emissions from school buses. In this study, the indoor and outdoor aerosol at four urban elementary schools serviced by diesel-powered school buses was characterized with respect to the particle number concentrations and size distributions as well as the PM2.5 mass concentrations and elemental compositions. It was determined that the presence of school buses significantly affected the outdoor particle size distribution, specifically in the ultrafine fraction. The time-weighted average of the total number concentration measured outside the schools was significantly associated with the bus and the car counts. The concentration increase was consistently observed during the morning drop-off hours and in most of the days during the afternoon pick-up period (although at a lower degree). Outdoor PM2.5 mass concentrations measured at schools ranged from 3.8 to 27.6 µg m−3. The school with the highest number of operating buses exhibited the highest average PM2.5 mass concentration. The outdoor mass concentrations of elemental carbon (EC) and organic carbon (OC) were also highest at the school with the greatest number of buses. Most (47/55) correlations between traffic-related elements identified in the outdoor PM2.5 were significant with elements identified in the indoor PM2.5. Significant associations were observed between indoor and outdoor aerosols for EC, EC/OC, and the total particle number concentration. Day-to-day and school-to-school variations in Indoor/Outdoor (I/O) ratios were related to the observed differences in opening windows and doors, which enhanced the particle penetration, as well as indoor activities at schools. Overall, the results on I/O ratio obtained in this study reflect the sizes of particles emitted by diesel-powered school bus engines (primarily, an ultrafine fraction capable of penetrating indoors). PMID:25904818

Reducing indoor residential exposures to outdoor pollutants

Energy Technology Data Exchange (ETDEWEB)

Sherman, Max H.; Matson, Nance E.

2003-07-01

The basic strategy for providing indoor air quality in residences is to dilute indoor sources with outdoor air. This strategy assumes that the outdoor air does not have pollutants at harmful levels or that the outdoor air is, at least, less polluted than the indoor air. When this is not the case, different strategies need to be employed to ensure adequate air quality in the indoor environment. These strategies include ventilation systems, filtration and other measures. These strategies can be used for several types of outdoor pollution, including smog, particulates and toxic air pollutants. This report reviews the impacts that typical outdoor air pollutants can have on the indoor environment and provides design and operational guidance for mitigating them. Poor quality air cannot be used for diluting indoor contaminants, but more generally it can become an indoor contaminant itself. This paper discusses strategies that use the building as protection against potentially hazardous outdoor pollutants, including widespread pollutants, accidental events, and potential attacks.

OUTDOOR EDUCATION AND GEOGRAPHICAL EDUCATION

Directory of Open Access Journals (Sweden)

ANDREA GUARAN

2016-01-01

Full Text Available This paper focuses on the reflection on the relationship between values and methodological principles of Outdoor Education and spatial and geographical education perspectives, especially in pre-school and primary school, which relates to the age between 3 and 10 years. Outdoor Education is an educational practice that is already rooted in the philosophical thought of the 16th and the 17th centuries, from John Locke to Jean-Jacques Rousseau, and in the pedagogical thought, in particular Friedrich Fröbel, and it has now a quite stable tradition in Northern Europe countries. In Italy, however, there are still few experiences and they usually do not have a systematic and structural modality, but rather a temporarily and experimentally outdoor organization. In the first part, this paper focuses on the reasons that justify a particular attention to educational paths that favour outdoors activities, providing also a definition of outdoor education and highlighting its values. It is also essential to understand that educational programs in open spaces, such as a forest or simply the schoolyard, surely offers the possibility to learn geographical situations. Therefore, the question that arises is how to finalize the best stimulus that the spatial location guarantees for the acquisition of knowledge, skills and abilities about space and geography.

Benchmarking Outdoor Expeditionary Program Risk Management Strategies

Science.gov (United States)

Meerts-Brandsma, Lisa; Furman, Nate; Sibthorp, Jim

2017-01-01

In 2003, the University of Utah and the National Outdoor Leadership School (NOLS) completed a study that developed a risk management taxonomy in the outdoor adventure industry and assessed how different outdoor expeditionary programs (OEPs) managed risk (Szolosi, Sibthorp, Paisley, & Gookin, 2003). By unifying the language around risk, the…

Hinterbrand Lodge Outdoor Education Center. Program Information.

Science.gov (United States)

Dependents Schools (DOD), Washington, DC. European Area.

Describing Department of Defense Dependents Schools Europe (DODDSEUR) use of Hinterbrand Lodge Outdoor Education Center, this document is directed to sponsors wishing to take groups to Hinterbrand for one or more of the five program options (outdoor education week, teacher weekend, school-designed outdoor education program, administrative faculty…

A Phenomenology of Outdoor Education Leader Experiences

Science.gov (United States)

Field, Stephanie C.; Lauzon, Lara L.; Meldrum, John T.

2016-01-01

Limited qualitative research exists on the experiences of outdoor education leaders. The purpose of this phenomenological study was to explore the job-related experiences of outdoor education leaders within and outside the workplace. Five participants who had experience as outdoor education leaders completed in-depth, one-on-one interviews about…

Outdoor Education: Definition and Philosophy.

Science.gov (United States)

Ford, Phyllis

Because outdoor education programs occur in every geographic location, are sponsored by all levels of educational institutions, state and local government agencies, and private entrepreneurs, and have no nationally standardized curriculum or measures of competency or knowledge, outdoor education may best be defines as "education in, about, and for…

Rotational particle separator: A new method for separating fine particles and mist from gases

NARCIS (Netherlands)

Brouwers, J.J.H.

1996-01-01

An account is given of the patented technique of the rotational particle separator for separating solid and liquid particles of diameter 0.1 µm and larger from gases. Attention is focused on the working principle, fluid mechanical constraints, particle design, separation performance, power

Position Statement on Active Outdoor Play.

Science.gov (United States)

Tremblay, Mark S; Gray, Casey; Babcock, Shawna; Barnes, Joel; Bradstreet, Christa Costas; Carr, Dawn; Chabot, Guylaine; Choquette, Louise; Chorney, David; Collyer, Cam; Herrington, Susan; Janson, Katherine; Janssen, Ian; Larouche, Richard; Pickett, William; Power, Marlene; Sandseter, Ellen Beate Hansen; Simon, Brenda; Brussoni, Mariana

2015-06-08

A diverse, cross-sectorial group of partners, stakeholders and researchers, collaborated to develop an evidence-informed Position Statement on active outdoor play for children aged 3-12 years. The Position Statement was created in response to practitioner, academic, legal, insurance and public debate, dialogue and disagreement on the relative benefits and harms of active (including risky) outdoor play. The Position Statement development process was informed by two systematic reviews, a critical appraisal of the current literature and existing position statements, engagement of research experts (N=9) and cross-sectorial individuals/organizations (N=17), and an extensive stakeholder consultation process (N=1908). More than 95% of the stakeholders consulted strongly agreed or somewhat agreed with the Position Statement; 14/17 participating individuals/organizations endorsed it; and over 1000 additional individuals and organizations requested their name be listed as a supporter. The final Position Statement on Active Outdoor Play states: "Access to active play in nature and outdoors--with its risks--is essential for healthy child development. We recommend increasing children's opportunities for self-directed play outdoors in all settings--at home, at school, in child care, the community and nature." The full Position Statement provides context for the statement, evidence supporting it, and a series of recommendations to increase active outdoor play opportunities to promote healthy child development.

Outdoor Acoustics as a General Discipline

DEFF Research Database (Denmark)

Rasmussen, Karsten Bo

1999-01-01

A tutorial paper exploring the characteristics of sound outdoors. Outdoor acoustics is contrasted to room acoustics. A number of important aspects of outdoor acoustics are exemplified and theoretical approaches are outlined. These are influence of ground impedance, influence of weather, screening...... to the application in question. In this way results providing a certain level of accuracy are obtained using methods which are balanced with the accuracy of the input data. Advanced measurement techniques are looked into and suggestions for future research are made...

Group Cooperation in Outdoor Education

Science.gov (United States)

Matthews, Bruce E.

1978-01-01

Utilizing the Beatles' Yellow Submarine fantasy (e.g., the Blue Meanies), this outdoor education program is designed for sixth graders and special education students. Activities developed at the Cortland Resident Outdoor Education Camp include a series of group stress/challenge activities to be accomplished by everyone in the group, as a group.…

Effects of oral administration of titanium dioxide fine-sized particles on plasma glucose in mice.

Science.gov (United States)

Gu, Ning; Hu, Hailong; Guo, Qian; Jin, Sanli; Wang, Changlin; Oh, Yuri; Feng, Yujie; Wu, Qiong

2015-12-01

Titanium dioxide (TiO2) is an authorized additive used as a food colorant, is composed of nano-sized particles (NP) and fine-sized particles (FP). Previous study reported that oral administration of TiO2 NPs triggers an increase in plasma glucose of mice. However, no previous studies have focused on toxic effects of TiO2 FPs on plasma glucose homeostasis following oral administration. In the current study, mice were orally administered TiO2 FPs greater than 100 nm in size (64 mg/kg body weight per day), and effects on plasma glucose levels examined. Our results showed that titanium levels was not changed in mouse blood, livers and pancreases after mice were orally administered TiO2 FPs. Biochemical analyzes showed that plasma glucose and ROS levels were not affected by TiO2 FPs. Histopathological results showed that TiO2 FPs did not induce pathology changes in organs, especially plasma glucose homeostasis regulation organs, such as pancreas and liver. Western blotting showed that oral administration of TiO2 FPs did not induce insulin resistance (IR) in mouse liver. These results showed that, TiO2 FPs cannot be absorbed via oral administration and affect plasma glucose levels in mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

Viscous properties of ferrofluids containing both micrometer-size magnetic particles and fine needle-like particles

Energy Technology Data Exchange (ETDEWEB)

Ido, Yasushi, E-mail: ido.yasushi@nitech.ac.jp [Department of Electric and Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya (Japan); Nishida, Hitoshi [Department of Electrical and Control Systems Engineering, National Institute of Technology, Toyama College, 13 Hongo-cho, Toyama (Japan); Iwamoto, Yuhiro [Department of Electric and Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya (Japan); Yokoyama, Hiroki [KYB Corporation, 2-4-1 Hamamatsu-cho, Minato-ku, Tokyo (Japan)

2017-06-01

Ferrofluids containing both micrometer-size spherical magnetic particles and nanometer-size needle-like nonmagnetic hematite particles were newly produced. Average length of long axis of the needle-like nonmagnetic particles was 194 nm and the aspect ratio was 8.3. Shear stress and viscosity were measured using the rheometer with the additional equipment for viscosity measurements in the presence of magnetic field. When the total volume fraction of particles in the fluid is constant (0.30), there is the specific mixing ratio of the particles to increase viscosity of the fluid drastically in the absence of magnetic field due to the percolation phenomenon. The fluid of the specific mixing ratio shows solid-like behavior even in the absence of magnetic field. Mixing the needle-like nonmagnetic particles causes strong yield stress and strong viscous force in the presence of magnetic field. - Highlights: • Viscous properties of new magnetic functional fluids were studied experimentally. • The new fluids contain spherical magnetic particles and needle-like particles. • Percolation occurs in the fluid of specific mixing ratio of particles without field. • The fluid of the specific mixing ratio behaves like solid without field. • Mixing needle-like particles causes strong yield stress of the fluid in the field.

Household air pollution and personal inhalation exposure to particles (TSP/PM2.5/PM1.0/PM0.25) in rural Shanxi, North China

International Nuclear Information System (INIS)

Huang, Ye; Du, Wei; Chen, Yuanchen; Shen, Guofeng; Su, Shu; Lin, Nan; Shen, Huizhong; Zhu, Dan; Yuan, Chenyi; Duan, Yonghong; Liu, Junfeng; Li, Bengang; Tao, Shu

2017-01-01

Personal exposure to size-segregated particles among rural residents in Shanxi, China in summer, 2011 were investigated using portable carried samplers (N = 84). Household air pollution was simultaneously studied using stationary samplers in nine homes. Information on household fuel types, cooking activity, smoking behavior, kitchen ventilation conditions etc., were also collected and discussed. The study found that even in the summer period, the daily average concentrations of PM 2.5 and PM 1.0 in the kitchen were as high as 376 ± 573 and 288 ± 397 μg/m 3 (N = 6), that were nearly 3 times of 114 ± 81 and 97 ± 77 μg/m 3 in the bedroom (N = 8), and significantly higher than those of 64 ± 28 and 47 ± 21 μg/m 3 in the outdoor air (N = 6). The personal daily exposure to PM 2.5 and PM 1.0 were 98 ± 52 and 77 ± 47 μg/m 3 , respectively, that were lower than the concentrations in the kitchen but higher than the outdoor levels. The mass fractions of PM 2.5 in TSP were 90%, 72%, 65% and 68% on average in the kitchen, bedroom, outdoor air and personal inhalation exposure, respectively, and moreover, a majority of particles in PM 2.5 had diameters less than 1.0 μm. Calculated time-weighted average exposure based on indoor and outdoor air concentrations and time spent indoor and outdoor were positively correlated but, was ∼33% lower than the directly measured exposure. The daily exposure among those burning traditional solid fuels could be lower by ∼41% if the kitchen was equipped with an outdoor chimney, but was still 8–14% higher than those household using cleaning energies, like electricity and gas. With a ventilator in the kitchen, the exposure among the population using clean energies could be further reduced by 10–24%. - Highlights: • High inhalation exposure of fine PM 2.5 and PM 1.0 among rural residents. • Smoking prevails on cooking in increasing exposure to finer particles. • PM exposure could be reduced by �

Carbon fuel particles used in direct carbon conversion fuel cells

Science.gov (United States)

Cooper, John F.; Cherepy, Nerine

2012-10-09

A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells

Science.gov (United States)

Cooper, John F.; Cherepy, Nerine

2008-10-21

A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

The green synthesis of fine particles of gold using an aqueous extract of Monotheca buxifolia (Flac.)

Science.gov (United States)

Anwar, Natasha; Khan, Abbas; Shah, Mohib; Azam, Andaleeb; Zaman, Khair; Parven, Zahida

2016-12-01

This study deals with the synthesis and physicochemical investigation of gold nanoparticles using an aqueous extract of Monotheca buxifolia (Flac.). On the treatment of aqueous solution of tetrachloroauric acid with the plant extract, gold nanoparticles were rapidly fabricated. The synthesized particles were characterized by UV-Vis spectrophotometry (UV), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX) and Scanning electron microscopy (SEM). The formation of AuNPs was confirmed by noting the change in color through visual observations as well as via UV-Vis spectroscopy. UV‒Vis spectrum of the aqueous medium containing gold nanoparticles showed an absorption peak at around 540 nm. FTIR was used to identify the chemical composition of gold nanoparticles and Au-capped plant extract. The presence of elemental gold was also confirmed through EDX analysis. SEM analysis of the gold nanoparticles showed that they have a uniform spherical shape with an average size in the range of 70-78 nm. This green system showed to be better capping and stabilizing agent for the fine particles. Further, the antioxidant activity of Monotheca buxifolia (Flac.) extract and Au-capped with the plant extract was also evaluated using FeCl3/K3[Fe(CN)]6 in vitro assay.

Towards Consensus on the Nature of Outdoor Education. Editorial.

Science.gov (United States)

Higgins, Peter; Loynes, Chris

1997-01-01

At a European conference in Finland, various outdoor education organizations drafted a statement of intent for the newly created European Institute for Outdoor Adventure Education. Their common view of outdoor education is that it strives to stimulate personal and social development experientially through some experience of the outdoors. Discusses…

Contributions of fuel combustion to pollution by airborne particles in urban and non-urban environments

International Nuclear Information System (INIS)

1995-06-01

The application of ion beam analysis (IBA) techniques to aerosol pollution problems has been used in a number of countries since the late 1970's and early 1980's. The technique, however, had not been tested in Australia. This document is the final report of a project which aimed to establish a fine particle monitoring network covering the greater Wollongong/Sydney/ Newcastle ares, investigate the relationships between fuel combustion and fine particle aerosols in urban and non urban environments, add to the limited database of baseline information on concentrations of fine particles resulting from such processes as fossil fuel burning and industrial manufacturing, identify and quantify sources of fine particles in New South Wales, and introduce into Australia accelerator based IBA techniques for the analysis of filter papers obtained from large scale monitoring networks. These objectives were addressed by the project which identified and quantified some sources of fine particles and established some relationships between fuel combustion and fine aerosols. More work is required to fully quantify relationships between natural and anthropogenic fine particle sources. 24 tabs., 44 figs., 83 refs

Rock Magnetic Characterization of fine Particles from car Engines, Break pads and Tobacco: An Environmental Pilot Study

Science.gov (United States)

Herrero-Bervera, E.; Lopez, V. A.; Gerstnecker, K.; Swilley, B.

2017-12-01

Today, it is very well known that small magnetic particles are very harmful to the health of humans. For the first time we have conducted an environmental pilot study of fine magnetic particles on the island of Oahu, Hawaii, of particulate matter (pm) 60, pm=10, and pm= 2.5. In order to do a rock magnetic characterization we have preformed low field susceptibility versus temperature (k-T) experiments to determine the Curie points of small particles collected from exhaust pipes, as well as from brake pads of 4 different types of car engines using octane ratings of 85, 87 and 92. The Curie point determinations are very well defined and range from 292 °C through 393 °C to 660 °C. In addition, we have conducted magnetic granulometry experiments on raw tobacco, burnt ashes as well as on car engines and brake pads in question. The results of the experiments show ferro- and ferrimagnetic hysteresis loops with magnetic grain sizes ranging from superparamagnetic-multidomain (SP_MD), multi-domain (MD) and pseudo-single domain (PSD) shown on the modified Day et al. diagram of Dunlop (2002). Thus far, the results we have obtained from this pilot study are in agreement with other studies conducted from cigarette ashes from Bulgaria (Jordanova et al., 2005). Our results could be correlated to the traffic-related PM in Rome, Italy where the SP fraction mainly occurs as coating of MD particles that originated by localized stress in the oxidized outer shell surrounding the unoxidized core of magnetite like grains as published by Sagnotti and Winkler (2012).

Extrinsic lactose fines improve dry powder inhaler formulation performance of a cohesive batch of budesonide via agglomerate formation and consequential co-deposition.

Science.gov (United States)

Kinnunen, Hanne; Hebbink, Gerald; Peters, Harry; Huck, Deborah; Makein, Lisa; Price, Robert

2015-01-15

The aim of the study was to investigate how the fine particle content of lactose carriers prepared with different types of lactose fines regulates dry powder inhaler (DPI) formulation performance of a cohesive batch of micronised budesonide. Budesonide formulations (0.8 wt%) were prepared with three different lactose carriers (Lactohale (LH) LH100, 20 wt% LH210 in LH100 and 20 wt% LH300 in LH100). Fine particle fraction of emitted dose (FPFED) and mean mass aerodynamic diameter (MMAD) of budesonide was assessed with a Next Generation Impactor (NGI) using a Cyclohaler at 90 l/min. Morphological and chemical characteristics of particles deposited on Stage 2 were determined using a Malvern Morphologi G3-ID. The results indicate that increasing concentration of lactose fines (agglomerates. Presence of agglomerates on Stage 2 was confirmed by morphological analysis of particles. Raman analysis of material collected on Stage 2 indicated that the more fine lactose particles were available the more agglomerates of budesonide and lactose were delivered to Stage 2. These results suggest drug-fines agglomerate formation is an important mechanism for how lactose fines improve and regulate DPI formulation performance. Copyright © 2014 Elsevier B.V. All rights reserved.

Segmenting texts from outdoor images taken by mobile phones using color features

Science.gov (United States)

Liu, Zongyi; Zhou, Hanning

2011-01-01

Recognizing texts from images taken by mobile phones with low resolution has wide applications. It has been shown that a good image binarization can substantially improve the performances of OCR engines. In this paper, we present a framework to segment texts from outdoor images taken by mobile phones using color features. The framework consists of three steps: (i) the initial process including image enhancement, binarization and noise filtering, where we binarize the input images in each RGB channel, and apply component level noise filtering; (ii) grouping components into blocks using color features, where we compute the component similarities by dynamically adjusting the weights of RGB channels, and merge groups hierachically, and (iii) blocks selection, where we use the run-length features and choose the Support Vector Machine (SVM) as the classifier. We tested the algorithm using 13 outdoor images taken by an old-style LG-64693 mobile phone with 640x480 resolution. We compared the segmentation results with Tsar's algorithm, a state-of-the-art camera text detection algorithm, and show that our algorithm is more robust, particularly in terms of the false alarm rates. In addition, we also evaluated the impacts of our algorithm on the Abbyy's FineReader, one of the most popular commercial OCR engines in the market.

Thermal insulator made of ultra fine particles of silica. Chobiryushi silica kei dannetsuzai

Energy Technology Data Exchange (ETDEWEB)

Eguchi, T.

1991-05-30

An overview was presented of properties and applications of thermal insulator made of ultra fine powder of silica, MICROTHERM. The thermal conductivity of MICROTHERM is as low as (1/3) - (1/4) of that of conventional thermal insulator, because it is mainly composed of fumed silica or aero gel and formed into porous structure. In addition, metal oxide of special particle size is added to it in order to reject the radiative heat. The thermal insulation property and the mechanical strength of MICROTHERM is not affected by a sudden change in temperature and moisture. The standard type of MICROTHERM can be used at a temperature up to 950 {degree}C, while the high temperature type MICROTHERM can stand a high temperature up to 1025 {degree}C for long period of time. The thickness of insulator can be reduced markedly by using MICROTHERM as compared with the use of conventional insulating materials. Many new products in which MICROTHERM is used came into market. New type kilt, Semi-cylindrical block, Super high temperature MICROTHERM are just a few examples. Variety of application and energy saving effect are attracting public attention. 11 figs.

Method and equipment to determine fine dust concentrations

International Nuclear Information System (INIS)

Breuer, H.; Gebhardt, J.; Robock, K.

1979-01-01

The measured values for the fine dust concentration are obtained by optical means which where possible agree with the probable deposited quantity of fine dust in the pulmonary alveoli. This is done by receiving the strong radiation produced in dependence of the particle size at an angle of 70 0 to the angle of incidence of the primary beam. The wavelength of the primary radiation is in the region of 1000 to 2000 nm. (RW) [de

Split-second recognition: what makes outdoor advertising work?

NARCIS (Netherlands)

van Meurs, A.; Aristoff, M.

2009-01-01

CBS Outdoor used a tachistoscope to determine how long it takes to recognize the brand/product advertised in 187 outdoor posters in the Netherlands. Additionally, CBS Outdoor measured the creative appeal of these advertisements. Using 80 content and format variables, an explanatory model was

Association of fine particulate matter from different sources with daily mortality in six US cities

Energy Technology Data Exchange (ETDEWEB)

Laden, F.; Neas, L.M.; Dockery, D.W.; Schwartz, J. [Harvard University, Boston, MA (USA). School of Medicine, Brigham & Womens Hospital

2000-07-01

In this study, the authors use the elemental composition of size-fractionated particles to identify several distinct source-related fractions of fine particles and examined the association of these fractions with daily mortality in each of six US cities. Using specific rotation factor analysis for each city, a silicon factor classified as soil and crustal material, a lead factor classified as motor vehicle exhaust, a selenium factor representing coal combustion, and up to two additional factors were identified. Daily counts of deaths from National Center for Health Statistics records were extracted and city-specific associations of mortality with each source factor were estimated. Combined effect estimates were calculated as the inverse variance weighted mean of the city-specific estimates. Results indicated that combustion particles in the fine fraction from mobile and coal combustion sources, but not fine crustal particles, are associated with increased mortality.

Fines Classification Based on Sensitivity to Pore-Fluid Chemistry

KAUST Repository

Jang, Junbong

2015-12-28

The 75-μm particle size is used to discriminate between fine and coarse grains. Further analysis of fine grains is typically based on the plasticity chart. Whereas pore-fluid-chemistry-dependent soil response is a salient and distinguishing characteristic of fine grains, pore-fluid chemistry is not addressed in current classification systems. Liquid limits obtained with electrically contrasting pore fluids (deionized water, 2-M NaCl brine, and kerosene) are combined to define the soil "electrical sensitivity." Liquid limit and electrical sensitivity can be effectively used to classify fine grains according to their fluid-soil response into no-, low-, intermediate-, or high-plasticity fine grains of low, intermediate, or high electrical sensitivity. The proposed methodology benefits from the accumulated experience with liquid limit in the field and addresses the needs of a broader range of geotechnical engineering problems. © ASCE.

Fines classification based on sensitivity to pore-fluid chemistry

Science.gov (United States)

Jang, Junbong; Santamarina, J. Carlos

2016-01-01

The 75-μm particle size is used to discriminate between fine and coarse grains. Further analysis of fine grains is typically based on the plasticity chart. Whereas pore-fluid-chemistry-dependent soil response is a salient and distinguishing characteristic of fine grains, pore-fluid chemistry is not addressed in current classification systems. Liquid limits obtained with electrically contrasting pore fluids (deionized water, 2-M NaCl brine, and kerosene) are combined to define the soil “electrical sensitivity.” Liquid limit and electrical sensitivity can be effectively used to classify fine grains according to their fluid-soil response into no-, low-, intermediate-, or high-plasticity fine grains of low, intermediate, or high electrical sensitivity. The proposed methodology benefits from the accumulated experience with liquid limit in the field and addresses the needs of a broader range of geotechnical engineering problems.

Conference particulate matter and indoor environment, I.N.E.R.I.S.; Particulate matter and indoor environment

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

Comprehensive characterisation of indoor and outdoor air as well as pollution emission sources Integrated health and environmental risk assessment Scientific and technical basis for airborne pollution management and control Fine and coarse particles. The sources of indoor air pollution are originate separately, are transported separately, are removed from atmosphere by different mechanisms, have different optical properties, have different chemical properties, require different control techniques. for the health effects due to particles, they decrease the lung function, increase respiratory symptoms, increase chronic obstructive pulmonary diseases, increased cardiovascular disease, increased mortality. The different sources contributing to the highest concentrations are: concentrations: tobacco smoking, cooking, vacuuming, dusting and sweeping, heaters, stoves, fireplaces and some other non identified sources. In the future we want more focus on fine and ultra fine particles, investigate source apportionment of particles, better understanding and quantification of exposure, to implement guidelines for particle concentration in indoor air and find better cleaning technologies. (N.C.)

Parents' Perceptions of Preschool Activities: Exploring Outdoor Play

Science.gov (United States)

Jayasuriya, Avanthi; Williams, Marcia; Edwards, Todd; Tandon, Pooja

2016-01-01

Research Findings: Outdoor play is important for children's health and development, yet many preschool-age children in child care settings do not receive the recommended 60 min/day of outdoor play. Child care providers have previously described parent-related barriers to increasing outdoor playtime, including parents not providing appropriate…

A novel waste water cleanup, fines sequestration and consolidation technology for oil sands applications

Energy Technology Data Exchange (ETDEWEB)

Soane, D.; Ware, W.; Mahoney, R.; Kincaid, P. [Soane Energy LLC, Cambridge, MA (United States)

2010-07-01

This paper discussed a wastewater technology designed to rapidly sequester suspended fines and other pollutants from the tailings produced during oil sands processes. The technology can also be used to clarify existing tailings ponds, and is expected to help address growing environmental concerns over the remediation of oil sands tailings. The ATA system is comprised of the following 3 components: (1) an activator polymer, (2) a tether polymer, and (3) an anchor particle. A small dose of the activator polymer is added to the fine or mature tailings, which then causes the suspended clay fines to aggregate. The anchor particles are then coated with the tether polymer. The anchor particle is formed from sand derived from coarser tailings. The tether-bearing anchor particles bind to the aggregated clay fines in the activated tailings to form robust complexes that can easily be separated from the waste stream. Output streams from the ATA process include a clean water stream that can be reused in oil sands extraction processes; and a dewatered solid that can be used as landfill as well as in construction and reclamation applications. The sensible heat retained in the recycled water is expected to also reduce the energy requirements of the oil sands extraction process. 6 refs., 1 tab., 5 figs.

Gas-particle phase partitioning and particle size distribution of chlorinated and brominated polycyclic aromatic hydrocarbons in haze.

Science.gov (United States)

Jin, Rong; Zheng, Minghui; Yang, Hongbo; Yang, Lili; Wu, Xiaolin; Xu, Yang; Liu, Guorui

2017-12-01

Chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/Br-PAHs) are emerging semi-volatile organic pollutants in haze-associated particulate matter (PM). Their gas-particle phase partitioning and distribution among PM fractions have not been clarified. Clarification would increase understanding of atmospheric behavior and health risks of Cl/Br-PAHs. In this study, samples of the gas phase and 4 PM phases (aerodynamic diameters (d ae ) > 10 μm, 2.5-10 μm, 1.0-2.5 μm, and <1.0 μm) were collected simultaneously during haze events in Beijing and analyzed. Normalized histogram distribution indicated that the Cl/Br-PAHs tended to adhere to fine particles. Over 80% of the Cl-PAHs and 70% of the Br-PAHs were associated with fine PM (d ae  < 2.5 μm). The gas-particle phase partitioning and PM distribution of Cl/Br-PAHs when heating of buildings was required, which was associated with haze events, were obviously different from those when heating was not required. The relationship between the logarithmic geometric mean diameters of the Cl/Br-PAH congeners and reciprocal of the temperature (1/T) suggested that low air temperatures during the heating period could lead to high proportions of Cl/Br-PAHs in the fine particles. Increased coal burning during the heating period also contributed to high Cl/Br-PAH loads in the fine particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

New Mechanisms to Explain the Effects of Added Lactose Fines on the Dispersion Performance of Adhesive Mixtures for Inhalation

Science.gov (United States)

Grasmeijer, Floris; Lexmond, Anne J.; van den Noort, Maarten; Hagedoorn, Paul; Hickey, Anthony J.; Frijlink, Henderik W.; de Boer, Anne H.

2014-01-01

Fine excipient particles or ‘fines’ have been shown to improve the dispersion performance of carrier-based formulations for dry powder inhalation. Mechanistic formulation studies have focussed mainly on explaining this positive effect. Previous studies have shown that higher drug contents may cause a decrease in dispersion performance, and there is no reason why this should not be true for fines with a similar shape, size and cohesiveness as drug particles. Therefore, the effects on drug detachment of ‘fine lactose fines’ (FLF, X50 = 1.95 µm) with a similar size and shape as micronised budesonide were studied and compared to those of ‘coarse lactose fines’ (CLF, X50 = 3.94 µm). Furthermore, interactions with the inhalation flow rate, the drug content and the mixing order were taken into account. The observed effects of FLF are comparable to drug content effects in that the detached drug fraction was decreased at low drug content and low flow rates but increased at higher flow rates. At high drug content the effects of added FLF were negligible. In contrast, CLF resulted in higher detached drug fractions at all flow rates and drug contents. The results from this study suggest that the effects of fines may be explained by two new mechanisms in addition to those previously proposed. Firstly, fines below a certain size may increase the effectiveness of press-on forces or cause the formation of strongly coherent fine particle networks on the carrier surface containing the drug particles. Secondly, when coarse enough, fines may prevent the formation of, or disrupt such fine particle networks, possibly through a lowering of their tensile strength. It is recommended that future mechanistic studies are based on the recognition that added fines may have any effect on dispersion performance, which is determined by the formulation and dispersion conditions. PMID:24489969

Seeking Resilience and Sustainability: Outdoor Education in Singapore

Science.gov (United States)

Martin, Peter; Ho, Susanna

2009-01-01

Outdoor education is not a universal value. Rather, outdoor education's contributions need to be grounded in time, place and culture. In this paper we describe the historical and cultural milieu that has enabled the emergence of outdoor education in Singapore and report on exploratory survey research into Singaporean teachers' conceptions of…

Physical Education & Outdoor Education: Complementary but Discrete Disciplines

Science.gov (United States)

Martin, Peter; McCullagh, John

2011-01-01

The Australian Council for Health, Physical Education and Recreation (ACHPER) includes Outdoor Education (OE) as a component of Physical Education (PE). Yet Outdoor Education is clearly thought of by many as a discrete discipline separate from Physical Education. Outdoor Education has a body of knowledge that differs from that of Physical…

Federal outdoor recreation trends: effects on economic opportunities

Science.gov (United States)

Eric White; J.M. Bowker; Ashley E. Askew; Linda L. Langner; J. Ross Arnold; Donald B.K. English

2016-01-01

Outdoor recreation is a central way that people interact with the natural environment. Federal land agencies are key providers of settings, facilities, and landscapes for recreation. Outdoor recreation is also an important driver of economic activity in rural communities near recreation destinations and across the United States. Future participation in outdoor...

Should people be physically active outdoors on smog alert days?

Science.gov (United States)

Campbell, Monica E; Li, Qian; Gingrich, Sarah E; Macfarlane, Ronald G; Cheng, Shouquan

2005-01-01

Given the importance of physical activity to well-being, there is a need to encourage people to be physically active year-round. At the same time, many people are vulnerable to adverse health effects from air pollution, especially on smog alert days. This study was undertaken to determine when air pollution levels tend to be lowest so that the public can modify strenuous outdoor activity accordingly. Existing hourly air pollution data for Toronto were analyzed to determine how pollutant levels varied from hour to hour throughout each 24-hour day, to identify the times when pollution levels are at their lowest on average. Pollutant levels vary throughout the day, with concentrations of some pollutants (such as ozone, particles and sulphur dioxide) being highest during mid-day, and others (such as carbon monoxide and nitrogen dioxide) being highest with morning rush hour. Overall, pollutant concentrations tend to be lowest before seven a.m. and after eight p.m. The public should be encouraged to maintain regular physical activity outdoors while monitoring any air pollution-related symptoms. The intensity of outdoor activity should be reduced, or activities replaced with indoor exercise, at those Air Quality Index (AQI) levels that trigger individual symptoms and when AQI values exceed 50. Where possible, strenuous activity should be taken when and where air pollution levels tend to be lowest, namely early in the morning and in low-traffic areas. More research is required to guide development of health protective advice on exercising when air quality is poor.

Outdoor radon variation in Romania

International Nuclear Information System (INIS)

Simion, Elena; Simion, Florin

2008-01-01

Full text: The results of a long-term survey (1992 - 2006) of the variations of outdoor radon concentrations in semi-natural location from Romania are reported in the present paper. Measurements, covering between two and four sessions of the day (morning, afternoon, evening and night), were performed on a daily bases by 37 Environmental Radioactivity Monitoring Stations from National Environmental Radioactivity Survey Network. The method used was based on indirect determination of outdoor radon from aerosol samples collected on glass micro-fibre filters by drawing the air through the filters. The sampling was performed in a fixed place at a height of 2 m above the ground surface. Total beta counting of aerosol samples collected was performed immediately and after 20 hours. Values recorded during the years of continuous measurement indicated the presence of several patterns in the long-term variation of outdoor radon concentration: diurnal, seasonal and annual variation. For diurnal variation, outdoor radon concentration shows a maximum values in the night (early hours) and minimum values by day (in the afternoon). On average, this maximum is a factor of 2 higher than the minimum. Late autumn - beginning of winter maximum and an early spring minimum are characteristic for seasonal patterns. In the long term a seasonal pattern was observed for diurnal variation, with an average diurnal maximum to minimum ratio of 1.33 in winter compared with 3.0 in the summer months. The variations of outdoor radon levels showed little correlation with the uranium concentration of the ground and were attributed to changes in soil moisture content. In dry seasons, because of the low precipitation, the soil was drying out in the summer allowing fractures to develop and radon to migrate easily through the ground. Depending on micro-climatic and geological conditions, outdoor radon average concentrations in different regions of Romania are from 1200 mBq/mc to 13065 mBq/mc. The smallest

Outdoor recreation and ethnicity

DEFF Research Database (Denmark)

Gentin, Sandra

recreation, activities, and preferred outdoor recreation areas) between the minority and majority populations and related these differences to the ethnic minorities’ cultural background. The second paper presents the empirical work of this thesis, which is based on a survey of adolescents’ outdoor recreation....... In the UK the focus on underrepresented groups seems closely related to the focus on equality for access, while specific focus on access for ethnic minorities is not addressed in the forest and nature legislation and the national forest programs in Denmark, Germany and the Netherlands. Paper 4 proposes...

Release of silver nanoparticles from outdoor facades

International Nuclear Information System (INIS)

Kaegi, Ralf; Sinnet, Brian; Zuleeg, Steffen; Hagendorfer, Harald; Mueller, Elisabeth; Vonbank, Roger; Boller, Markus; Burkhardt, Michael

2010-01-01

In this study we investigate the release of metallic silver nanoparticles (Ag-NP) from paints used for outdoor applications. A facade panel mounted on a model house was exposed to ambient weather conditions over a period of one year. The runoff volume of individual rain events was determined and the silver and titanium concentrations of 36 out of 65 runoff events were measured. Selected samples were prepared for electron microscopic analysis. A strong leaching of the Ag-NP was observed during the initial runoff events with a maximum concentration of 145 μ Ag/l. After a period of one year, more than 30% of the Ag-NP were released to the environment. Particles were mostly 2 S. - We provide direct evidence for the release of silver nanoparticles from exterior paints to the aquatic environment.

Indoor versus outdoor time in preschoolers at child care.

Science.gov (United States)

Tandon, Pooja S; Saelens, Brian E; Zhou, Chuan; Kerr, Jacqueline; Christakis, Dimitri A

2013-01-01

Being outdoors may have health benefits including being more physically active. Understanding the relationship between outdoor time and health is hampered by the difficulty of measuring outdoor time. To examine the accuracy and validity of light-sensor and GPS methods for quantifying outdoor time among those aged 3-5 years at child care. A total of 45 children (mean age 4.5 years, 64% boys) from five child care centers wore portable accelerometers with built-in light sensors and a separate GPS device around their waists during child care, providing 80,648 episodes (15 seconds each) for analysis. Direct observation (gold standard) of children being outdoors versus indoors was conducted for 2 days at each center. GPS signal-to-noise ratios, processed through the Personal Activity and Location Measurement System were used to define indoor versus outdoor locations. Receiver operating characteristic (ROC) analyses were used to determine thresholds for defining being indoors versus outdoors. Data were collected in Fall 2011, analyzed in 2012. Mean observed outdoor time was 63 [±44; range: 18-152] minutes/day. Mean light-sensor levels were significantly higher outdoors. The area under the ROC curve for location based on light sensor for all weather conditions was 0.82 (range: 0.70 on partly cloudy days to 0.97 on sunny days); for GPS, it was 0.89. The light sensor had a sensitivity of 74% and specificity of 86%. GPS had a sensitivity of 82% and specificity of 88%. A light sensor and a GPS device both distinguish indoor from outdoor time for preschoolers with moderate to high levels of accuracy. These devices can increase the feasibility and lower the cost of measuring outdoor time in studies of preschool children. Copyright © 2013 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

The influence of outdoor thermal environment on young Japanese females

DEFF Research Database (Denmark)

Sakoi, Tomonori; Ishii, Jin; Kondo, Emi

2014-01-01

The influence of short wave solar radiation appears to be strong outdoors in summer, and the influence of airflow appears to be strong outdoors in winter. The purpose of this paper was to clarify the influence of the outdoor environment on young Japanese females. This research shows the relations......The influence of short wave solar radiation appears to be strong outdoors in summer, and the influence of airflow appears to be strong outdoors in winter. The purpose of this paper was to clarify the influence of the outdoor environment on young Japanese females. This research shows...

Outdoor air dominates burden of disease from indoor exposures

DEFF Research Database (Denmark)

Hänninen, O.; Asikainen, A.; Carrer, P.

2014-01-01

Both indoor and outdoor sources of air pollution have significant public health impacts in Europe. Based on quantitative modelling of the burden of disease the outdoor sources dominate the impacts by a clear margin.......Both indoor and outdoor sources of air pollution have significant public health impacts in Europe. Based on quantitative modelling of the burden of disease the outdoor sources dominate the impacts by a clear margin....

Comparing on-road real-time simultaneous in-cabin and outdoor particulate and gaseous concentrations for a range of ventilation scenarios

Science.gov (United States)

Leavey, Anna; Reed, Nathan; Patel, Sameer; Bradley, Kevin; Kulkarni, Pramod; Biswas, Pratim

2017-10-01

Advanced automobile technology, developed infrastructure, and changing economic markets have resulted in increasing commute times. Traffic is a major source of harmful pollutants and consequently daily peak exposures tend to occur near roadways or while travelling on them. The objective of this study was to measure simultaneous real-time particulate matter (particle numbers, lung-deposited surface area, PM2.5, particle number size distributions) and CO concentrations outside and in-cabin of an on-road car during regular commutes to and from work. Data was collected for different ventilation parameters (windows open or closed, fan on, AC on), whilst travelling along different road-types with varying traffic densities. Multiple predictor variables were examined using linear mixed-effects models. Ambient pollutants (NOx, PM2.5, CO) and meteorological variables (wind speed, temperature, relative humidity, dew point) explained 5-44% of outdoor pollutant variability, while the time spent travelling behind a bus was statistically significant for PM2.5, lung-deposited SA, and CO (adj-R2 values = 0.12, 0.10, 0.13). The geometric mean diameter (GMD) for outdoor aerosol was 34 nm. Larger cabin GMDs were observed when windows were closed compared to open (b = 4.3, p-value = <0.01). When windows were open, cabin total aerosol concentrations tracked those outdoors. With windows closed, the pollutants took longer to enter the vehicle cabin, but also longer to exit it. Concentrations of pollutants in cabin were influenced by outdoor concentrations, ambient temperature, and the window/ventilation parameters. As expected, particle number concentrations were impacted the most by changes to window position/ventilation, and PM2.5 the least. Car drivers can expect their highest exposures when driving with windows open or the fan on, and their lowest exposures during windows closed or the AC on. Final linear mixed-effects models could explain between 88 and 97% of cabin pollutant

Optimization of heat pump system in indoor swimming pool using particle swarm algorithm

Energy Technology Data Exchange (ETDEWEB)

Lee, Wen-Shing; Kung, Chung-Kuan [Department of Energy and Refrigerating Air-Conditioning Engineering, National Taipei University of Technology, 1, Section 3, Chung-Hsiao East Road, Taipei (China)

2008-09-15

When it comes to indoor swimming pool facilities, a large amount of energy is required to heat up low-temperature outdoor air before it is being introduced indoors to maintain indoor humidity. Since water is evaporated from the pool surface, the exhausted air contains more water and specific enthalpy. In response to this indoor air, heat pump is generally used in heat recovery for indoor swimming pools. To reduce the cost in energy consumption, this paper utilizes particle swarm algorithm to optimize the design of heat pump system. The optimized parameters include continuous parameters and discrete parameters. The former consists of outdoor air mass flow and heat conductance of heat exchangers; the latter comprises compressor type and boiler type. In a case study, life cycle energy cost is considered as an objective function. In this regard, the optimized outdoor air flow and the optimized design for heating system can be deduced by using particle swarm algorithm. (author)

Fostering Trust in Outdoor Leaders: The Role of Personal Attributes

Science.gov (United States)

Shooter, Wynn; Paisley, Karen; Sibthorp, Jim

2012-01-01

This study examined trust development between participants of outdoor education programs and outdoor leaders. Participants were college students enrolled in outdoor education courses. Using a factorial survey design, the technical ability, interpersonal ability, benevolence, integrity, and gender of an outdoor leader was displayed randomly in a…

The influence of wind speed on airflow and fine particle transport within different building layouts of an industrial city.

Science.gov (United States)

Mei, Dan; Wen, Meng; Xu, Xuemei; Zhu, Yuzheng; Xing, Futang

2018-04-20

In atmospheric environment, the layout difference of urban buildings has a powerful influence on accelerating or inhibiting the dispersion of particle matters (PM). In industrial cities, buildings of variable heights can obstruct the diffusion of PM from industrial stacks. In this study, PM dispersed within building groups was simulated by Reynolds-averaged Navier-Stokes equations coupled Lagrangian approach. Four typical street building arrangements were used: (a) a low-rise building block with Height/base H/b = 1 (b = 20 m); (b) step-up building layout (H/b = 1, 2, 3, 4); (c) step-down building layout (H/b = 4, 3, 2, 1); (d) high-rise building block (H/b = 5). Profiles of stream functions and turbulence intensity were used to examine the effect of various building layouts on atmospheric airflow. Here, concepts of particle suspension fraction and concentration distribution were used to evaluate the effect of wind speed on fine particle transport. These parameters showed that step-up building layouts accelerated top airflow and diffused more particles into street canyons, likely having adverse effects on resident health. In renewal old industry areas, the step-down building arrangement which can hinder PM dispersion from high-level stacks should be constructed preferentially. High turbulent intensity results in formation of a strong vortex that hinders particles into the street canyons. It is found that an increase in wind speed enhanced particle transport and reduced local particle concentrations, however, it did not affect the relative location of high particle concentration zones, which are related to building height and layout. This study has demonstrated the height variation and layout of urban architecture affect the local concentration distribution of particulate matter (PM) in the atmosphere and for the first time that wind velocity has particular effects on PM transport in various building groups. The findings may have general implications in optimization

Chemical Characterization of the Indoor Air Quality of a University Hospital: Penetration of Outdoor Air Pollutants.

Science.gov (United States)

Scheepers, Paul T J; Van Wel, Luuk; Beckmann, Gwendolyn; Anzion, Rob B M

2017-05-08

For healthcare centers, local outdoor sources of air pollution represent a potential threat to indoor air quality (IAQ). The aim of this study was to study the impact of local outdoor sources of air pollution on the IAQ of a university hospital. IAQ was characterized at thirteen indoor and two outdoor locations and source samples were collected from a helicopter and an emergency power supply. Volatile organic compounds (VOC), acrolein, formaldehyde, nitrogen dioxide (NO₂), respirable particulate matter (PM-4.0 and PM-2.5) and their respective benz(a)pyrene contents were determined over a period of two weeks. Time-weighted average concentrations of NO₂ (4.9-17.4 μg/m³) and formaldehyde (2.5-6.4 μg/m³) were similar on all indoor and outdoor locations. The median concentration VOC in indoor air was 119 μg/m³ (range: 33.1-2450 μg/m³) and was fivefold higher in laboratories (316 μg/m³) compared to offices (57.0 μg/m³). PM-4.0 and benzo(a)pyrene concentration were lower in buildings serviced by a >99.95% efficiency particle filter, compared to buildings using a standard 80-90% efficiency filter ( p engines to any of the IAQ parameters measured in this study. Chemical IAQ was primarily driven by known indoor sources and activities.

Mobile Phones and Outdoor Advertising: Measurable Advertising

OpenAIRE

Quercia, Daniele; Di Lorenzo, Giusy; Calabrese, Francesco; Ratti, Carlo

2011-01-01

Television and newspapers sit at the top of many agency marketing plans, while outdoor advertising stays at the bottom. The reason for this is that it’s difficult to account for who views a billboard, so there is no way of consistently determining the effectiveness of outdoor advertising. As a result, agencies do not consider the medium and allocate their money elsewhere. To change this situation, one needs to create new credible audience measurements for the outdoor marketing industry. He...

Analysis of fine-dispersed chalk usage as mineral additive in the composition of sand aggrerate concrete

Directory of Open Access Journals (Sweden)

Светлана Николаевна Чепурная

2016-12-01

Full Text Available The research results of fine-disperse chalk addition on physical and mechanical properties of the cement stone and concrete are shown. It is determined that fine-disperse chalk addition in the binder composition increases the content of ultrafine particles. The chalk particles fill the pore space between the cement particles, increasing the packing density, which leads to a density increase, which consequently leads to improved physical and mechanical properties of the concrete: water tightness, cold resistance, corrosion resistance, crack resistance and other properties

Effects of chlorine and sulphur on particle formation in wood combustion performed in a laboratory scale reactor

Energy Technology Data Exchange (ETDEWEB)

Olli Sippula; Terttaliisa Lind; Jorma Jokiniemi [University of Kuopio, Kuopio (Finland). Fine Particle and Aerosol Technology Laboratory, Department of Environmental Sciences

2008-09-15

Fine particle formation in wood combustion was studied in a laboratory scale laminar flow reactor at various flue gas chlorine and sulphur concentrations. Aerosol samples were quenched at around 850{sup o}C using a porous tube diluter. Fine particle number concentrations, mass concentrations, size distributions and chemical compositions were measured. In addition, flue gas composition, including SO{sub 2} and HCl, was monitored. Experimental results were interpreted by thermodynamic equilibrium calculations. Addition of HCl clearly raised fine particle mass concentration (PM1.0) which was because of increased release of ash-forming material to fine particles. Especially the release of K, Na, Zn and Cd to fine particles increased. These species form chlorides which apparently increases their volatilization from the fuel. When a sufficient amount of SO{sub 2} was supplied in a chlorine rich combustion (S/Cl molar ratio from 4.7 to 7.5), most of the HCl stayed in the gas phase, release of ash-forming elements decreased and also fine particle concentrations dropped significantly. The sulphation of alkali metals is suggested to play a key role in the observed decrease in the fine particle concentration. It seems that the formation of sulphates leads to alkali metal retention in the coarse particle fraction. 27 refs., 11 figs., 1 tab.

Position Statement on Active Outdoor Play

Science.gov (United States)

Tremblay, Mark S.; Gray, Casey; Babcock, Shawna; Barnes, Joel; Costas Bradstreet, Christa; Carr, Dawn; Chabot, Guylaine; Choquette, Louise; Chorney, David; Collyer, Cam; Herrington, Susan; Janson, Katherine; Janssen, Ian; Larouche, Richard; Pickett, William; Power, Marlene; Sandseter, Ellen Beate Hansen; Simon, Brenda; Brussoni, Mariana

2015-01-01

A diverse, cross-sectorial group of partners, stakeholders and researchers, collaborated to develop an evidence-informed Position Statement on active outdoor play for children aged 3–12 years. The Position Statement was created in response to practitioner, academic, legal, insurance and public debate, dialogue and disagreement on the relative benefits and harms of active (including risky) outdoor play. The Position Statement development process was informed by two systematic reviews, a critical appraisal of the current literature and existing position statements, engagement of research experts (N = 9) and cross-sectorial individuals/organizations (N = 17), and an extensive stakeholder consultation process (N = 1908). More than 95% of the stakeholders consulted strongly agreed or somewhat agreed with the Position Statement; 14/17 participating individuals/organizations endorsed it; and over 1000 additional individuals and organizations requested their name be listed as a supporter. The final Position Statement on Active Outdoor Play states: “Access to active play in nature and outdoors—with its risks— is essential for healthy child development. We recommend increasing children’s opportunities for self-directed play outdoors in all settings—at home, at school, in child care, the community and nature.” The full Position Statement provides context for the statement, evidence supporting it, and a series of recommendations to increase active outdoor play opportunities to promote healthy child development. PMID:26062040

Position Statement on Active Outdoor Play

Directory of Open Access Journals (Sweden)

Mark S. Tremblay

2015-06-01

Full Text Available A diverse, cross-sectorial group of partners, stakeholders and researchers, collaborated to develop an evidence-informed Position Statement on active outdoor play for children aged 3–12 years. The Position Statement was created in response to practitioner, academic, legal, insurance and public debate, dialogue and disagreement on the relative benefits and harms of active (including risky outdoor play. The Position Statement development process was informed by two systematic reviews, a critical appraisal of the current literature and existing position statements, engagement of research experts (N = 9 and cross-sectorial individuals/organizations (N = 17, and an extensive stakeholder consultation process (N = 1908. More than 95% of the stakeholders consulted strongly agreed or somewhat agreed with the Position Statement; 14/17 participating individuals/organizations endorsed it; and over 1000 additional individuals and organizations requested their name be listed as a supporter. The final Position Statement on Active Outdoor Play states: “Access to active play in nature and outdoors—with its risks— is essential for healthy child development. We recommend increasing children’s opportunities for self-directed play outdoors in all settings—at home, at school, in child care, the community and nature.” The full Position Statement provides context for the statement, evidence supporting it, and a series of recommendations to increase active outdoor play opportunities to promote healthy child development.

Estimation of inhaled airborne particle number concentration by subway users in Seoul, Korea

International Nuclear Information System (INIS)

Kim, Minhae; Park, Sechan; Namgung, Hyeong-Gyu; Kwon, Soon-Bark

2017-01-01

Exposure to airborne particulate matter (PM) causes several diseases in the human body. The smaller particles, which have relatively large surface areas, are actually more harmful to the human body since they can penetrate deeper parts of the lungs or become secondary pollutants by bonding with other atmospheric pollutants, such as nitrogen oxides. The purpose of this study is to present the number of PM inhaled by subway users as a possible reference material for any analysis of the hazards to the human body arising from the inhalation of such PM. Two transfer stations in Seoul, Korea, which have the greatest number of users, were selected for this study. For 0.3–0.422 μm PM, particle number concentration (PNC) was highest outdoors but decreased as the tester moved deeper underground. On the other hand, the PNC between 1 and 10 μm increased as the tester moved deeper underground and showed a high number concentration inside the subway train as well. An analysis of the particles to which subway users are actually exposed to (inhaled particle number), using particle concentration at each measurement location, the average inhalation rate of an adult, and the average stay time at each location, all showed that particles sized 0.01–0.422 μm are mostly inhaled from the outdoor air whereas particles sized 1–10 μm are inhaled as the passengers move deeper underground. Based on these findings, we expect that the inhaled particle number of subway users can be used as reference data for an evaluation of the hazards to health caused by PM inhalation. - Highlights: • Size-dependent aerosol number was measured along the path of subway user. • Particles less than 0.4 μm were inhaled in outdoor but less so as deeper underground. • Coarse particles were inhaled significantly as users moved deeper underground. - We estimated the inhaled aerosol number concentration depending on particle size along the path of subway users.

Validity of a traffic air pollutant dispersion model to assess exposure to fine particles.

Science.gov (United States)

Kostrzewa, Aude; Reungoat, Patrice; Raherison, Chantal

2009-08-01

Fine particles (PM(2.5)) are an important component of air pollution. Epidemiological studies have shown health effects due to ambient air particles, particularly allergies in children. Since the main difficulty is to determine exposure to such pollution, traffic air pollutant (TAP) dispersions models have been developed to improve the estimation of individual exposure levels. One such model, the ExTra index, has been validated for nitrogen oxide concentrations but not for other pollutants. The purpose of this study was to assess the validity of the ExTra index to assess PM(2.5) exposure. We compared PM(2.5) concentrations calculated by the ExTra index to reference measures (passive samplers situated under the covered part of the playground), in 15 schools in Bordeaux, in 2000. First, we collected the input data required by the ExTra index: background and local pollution depending on traffic, meteorology and topography. Second, the ExTra index was calculated for each school. Statistical analysis consisted of a graphic description; then, we calculated an intraclass correlation coefficient. Concentrations calculated with the ExTra index and the reference method were similar. The ExTra index underestimated exposure by 2.2 microg m(-3) on average compared to the reference method. The intraclass correlation coefficient was 0.85 and its 95% confidence interval was [0.62; 0.95]. The results suggest that the ExTra index provides an assessment of PM(2.5) exposure similar to that of the reference method. Although caution is required in interpreting these results owing to the small number of sites, the ExTra index could be a useful epidemiological tool for reconstructing individual exposure, an important challenge in epidemiology.

Two-Step Single Particle Mass Spectrometry for On-Line Monitoring of Polycyclic Aromatic Hydrocarbons Bound to Ambient Fine Particulate Matter

Science.gov (United States)

Zimmermann, R.; Bente, M.; Sklorz, M.

2007-12-01

Polycyclic aromatic hydrocarbons (PAH) are formed as trace products in combustion processes and are emitted to the atmosphere. Larger PAH have low vapour pressure and are predominantly bound to the ambient fine particulate matter (PM). Upon inhalation, PAH show both, chronic human toxicity (i.e. many PAH are potent carcinogens) as well as acute human toxicity (i.e. inflammatory effects due to oxi-dative stress) and are discussed to be relevant for the observed health effect of ambient PM. Therefore a better understanding of the occurrence, dynamics and particle size dependence of particle bound-PAH is of great interest. On-line aerosol mass spectrometry in principle is the method of choice to investigate the size resolved changes in the chemical speciation of particles as well the status of internal vs. external mixing of chemical constituents. However the present available aerosol mass spectrometers (ATOFMS and AMS) do not allow detection of PAH from ambient air PM. In order to allow a single particle based monitoring of PAH from ambient PM a new single particle laser ionisation mass spectrometer was built and applied. The system is based on ATOFMS principle but uses a two- step photo-ionization. A tracked and sized particle firstly is laser desorbed (LD) by a IR-laser pulse (CO2-laser, λ=10.2 μm) and subsequently the released PAH are selectively ionized by an intense UV-laser pulse (ArF excimer, λ=248 nm) in a resonance enhanced multiphoton ionisation process (REMPI). The PAH-ions are detected in a time of flight mass spectrometer (TOFMS). A virtual impactor enrichment unit is used to increase the detection frequency of the ambient particles. With the current inlet system particles from about 400 nm to 10 μm are accessible. Single particle based temporal profiles of PAH containing particles ion (size distribution and PAH speciation) have been recorded in Oberschleissheim, Germany from ambient air. Furthermore profiles of relevant emission sources (e

Rotational particle separator: A new method for separating fine particles and mists from gases

NARCIS (Netherlands)

Brouwers, J.J.H.

1996-01-01

An account is given of the patented technique of the rotational particle separator for separating solid and liquid particles of diameter 0.1 µm and larger from gases. Attention is focussed on the working principle, fluid mechanical constraints, practical designs, separation performance, power

Planning School Grounds for Outdoor Learning

Science.gov (United States)

Wagner, Cheryl; Gordon, Douglas

2010-01-01

This publication covers the planning and design of school grounds for outdoor learning in new and existing K-12 facilities. Curriculum development as well as athletic field planning and maintenance are not covered although some references on these topics are provided. It discusses the different types of outdoor learning environments that can be…

Ultra fine particulates. Small particulates with large consequences?; Ultrafijn stof. Kleine deeltjes met grote gevolgen?

Energy Technology Data Exchange (ETDEWEB)

Hensema, A.; Keuken, M.; Kooter, I.; Verbeek, R.; Van Vugt, M. [TNO Science and Industry, Delft (Netherlands)

2009-02-15

The concentrations of ultra fine particles (and elementary carbon) have increased significantly near traffic routes. The amount of ultra fine particles (and the chemical composition of particulate matter) are related to traffic emissions and are therefore relevant to the established health effects. Better insight in the effectiveness of particulate matter policy requires more attention for ultra fine particles than just maintaining the standards for PM2,5 and PM10. [mk]. [Dutch] De concentraties van ultrafijne deeltjes (en elementair koolstof) zijn fors verhoogd in de buurt van verkeerswegen. Het aantal ultrafijne deeltjes (en de chemische samenstelling van fijnstof) gerelateerd aan verkeersemissies lijkt daarom relevant voor de vastgestelde gezondheidseffecten. Voor een beter inzicht in de effectiviteit van het fijnstofbeleid is meer aandacht nodig voor ultrafijne deeltjes dan alleen handhaving van de normen voor PM2,5 en PM10.

Cardiopulmonary benefits of reducing indoor particles of outdoor origin: a randomized, double-blind crossover trial of air purifiers.

Science.gov (United States)

Chen, Renjie; Zhao, Ang; Chen, Honglei; Zhao, Zhuohui; Cai, Jing; Wang, Cuicui; Yang, Changyuan; Li, Huichu; Xu, Xiaohui; Ha, Sandie; Li, Tiantian; Kan, Haidong

2015-06-02

Indoor exposure to fine particulate matter (PM2.5) from outdoor sources is a major health concern, especially in highly polluted developing countries such as China. Few studies have evaluated the effectiveness of indoor air purification on the improvement of cardiopulmonary health in these areas. This study sought to evaluate whether a short-term indoor air purifier intervention improves cardiopulmonary health. We conducted a randomized, double-blind crossover trial among 35 healthy college students in Shanghai, China, in 2014. These students lived in dormitories that were randomized into 2 groups and alternated the use of true or sham air purifiers for 48 h with a 2-week washout interval. We measured 14 circulating biomarkers of inflammation, coagulation, and vasoconstriction; lung function; blood pressure (BP); and fractional exhaled nitric. We applied linear mixed-effect models to evaluate the effect of the intervention on health outcome variables. On average, air purification resulted in a 57% reduction in PM2.5 concentration, from 96.2 to 41.3 μg/m3, within hours of operation. Air purification was significantly associated with decreases in geometric means of several circulating inflammatory and thrombogenic biomarkers, including 17.5% in monocyte chemoattractant protein-1, 68.1% in interleukin-1β, 32.8% in myeloperoxidase, and 64.9% in soluble CD40 ligand. Furthermore, systolic BP, diastolic BP, and fractional exhaled nitrous oxide were significantly decreased by 2.7%, 4.8%, and 17.0% in geometric mean, respectively. The impacts on lung function and vasoconstriction biomarkers were beneficial but not statistically significant. This intervention study demonstrated clear cardiopulmonary benefits of indoor air purification among young, healthy adults in a Chinese city with severe ambient particulate air pollution. (Intervention Study on the Health Impact of Air Filters in Chinese Adults; NCT02239744). Copyright © 2015 American College of Cardiology Foundation

Smelting reduction rate of fine Wustite particles in a CO gas-conveyed bed; CO gas yuso sonai Wustite biryushi no yoyu kangen sokudo

Energy Technology Data Exchange (ETDEWEB)

Hayashi, S; Iguchi, Y [Nagoya Institute of Technology, Nagoya (Japan)

1999-06-01

Using a laboratory scale fine particles-gas conveyed bed, the reduction rates of liquid wustite with CO gas were measured. CO-CO{sub 2} mixtures having various flow rates and compositions were flowed downward through a cylindrical reactor maintained at a constant temperature of 1,723 to 1,823K. A batch of pure spherical wustite particles (mean dia.: 48.5 {mu}m) was concurrently fed into the reactor at a small constant rate and reduced in a hot zone. The reduction process was found to proceed in such a manner that metallic iron particles were enclosed inside a wustite droplet. Rate analysis was made of one dimensional mass balance equations for particles and gas in a steady moving bed under an isothermal condition using the reaction rate for a single particle taking the shrinkage into consideration. Under relatively small reducing potentials, it was concluded that the major fraction of overall reaction resistance is attributable to chemical reaction. However, under higher reducing potentials, the reduction process was estimated to include some mass transfer resistances within the liquid oxide phase. From the temperature dependence of forward chemical reaction rate constants, the activation energy was evaluated to be 90.6 kJ/mol. (author)

Safety assessment of outdoor live fire range

Energy Technology Data Exchange (ETDEWEB)

NONE

1989-05-01

The following Safety Assessment (SA) pertains to the outdoor live fire range facility (LFR). The purpose of this facility is to supplement the indoor LFR. In particular it provides capacity for exercises that would be inappropriate on the indoor range. This SA examines the risks that are attendant to the training on the outdoor LFR. The outdoor LFR used by EG&G Mound is privately owned. It is identified as the Miami Valley Shooting Grounds. Mondays are leased for the exclusive use of EG&G Mound.

Production of fines during co-combustion of coal with biomass fuels by fragmentation and attrition

Energy Technology Data Exchange (ETDEWEB)

I. Gulyurtlu; D. Boavida; H. Lopes (and others) [DEECA-INETI, Lisbon (Portugal)

2005-07-01

Results are reported from a project funded by the RFCS Programme of the European Union. The aim is to investigate, experimentally and by modeling, the production of fine char and ash particles during co-combustion of coal with wastes and biofuels in circulating fluidized bed. Work was undertaken at installations of different scales. Polish and Colombian coals were base fuels. The additional fuels were two sewage sludges. Bed temperature, feeding system, sand particle size, devolatilisation behaviour and char burn-out were studied to verify their influence on the fine particle production. Modeling was also carried out to understand the mechanisms of fragmentation and attrition. Samples from bed and cyclone were collected to determine particle size distributions. 11 refs.

United States of America: outdoor recreation.

Science.gov (United States)

H.Ken Cordell; G.Theodore Green; V.R. Leeworthy; R. Stephens; M.J. Fly; Carter J. Betz

2005-01-01

the first nationwide survey of outdoor recreation in the USA was conducted in 1960 for the outdoor recreation resources review commission (ORRC, 1962; Cordell et al., 1996). since that time, seven additional national surveys have been conducted, in 1965, 1970, 1972, 1977, 1983, 1995, and 2000/01 - summary details are presented in Table 16.1.

Recovery of clean coal fines through a combination of gravity concentrator and flotation processes

Energy Technology Data Exchange (ETDEWEB)

Gupta, A.K.; Banerjee, P.K.; Dutta, A.; Mishra, A. [Tata Steel, Jamshedpur (India). Research & Development

2007-07-01

Flotation feed is a mixture of coarse and ultra-fine fractions. During conditioning of the flotation feed with collector and frother, the finer fraction consumes more reagents as compared to coarser particles. This is mainly due to more specific surface area of the ultra fine than the coarse fraction. This favors the adsorption of reagents toward ultra-finer fractions leads to less complete surface coverage of coarse particles and more entrainment of finer gangue particles. This results in the lower yield of coarse fractions from the flotation circuit and loss in selectivity. Hence, the major challenge is to improve the recovery of the coarser fraction and selectivity of ultra-fine fractions by improving flotation kinetics of all size fractions. This article deals with an approach to overcome the improper reagent adsorption by fine and coarse coal fractions in the flotation circuit through an innovative washing circuit containing gravity operation and flotation processes. Flotation performance between a new washing circuit having stub cyclone and flotation and normal single-stage reagent addition flotation process is compared in terms of selectivity, separation efficiency, rate constant, and size-wise recovery. The washing circuit having stub cyclone and flotation processes improves the fine clean coal yield by 10% and reduces the consumption of reagent compared to the normal single-stage reagent addition flotation process.

Outdoor skaber særlig professionel identitet

DEFF Research Database (Denmark)

Kjeldsen, Lis Reinholdt; Lybæk-Hansen, Esper

2015-01-01

På pædagoguddannelsen i Horsens tilbydes årligt en toning af pædagoguddannelsen i Outdoor - en beskrivelse......På pædagoguddannelsen i Horsens tilbydes årligt en toning af pædagoguddannelsen i Outdoor - en beskrivelse...

Sources of organic compounds in fine soil and sand particles during winter in the metropolitan area of Riyadh, Saudi Arabia.

Science.gov (United States)

Rushdi, Ahmed I; Al-Mutlaq, Khalid; Simoneit, Bernd R T

2005-11-01

Major advances have been made in molecular marker analysis to distinguish between natural and anthropogenic organic matter inputs to the atmosphere. Resuspension of soil and sand by wind is one of the major mechanisms that produces particle dusts in the atmosphere. Soil and sand samples from the Riyadh area were collected in winter 2002, sieved to remove coarse particles and extracted with a mixture of dichloromethane and methanol (3:1, v:v). The total extracts were analyzed by gas chromatography-mass spectrometry in order to characterize the contents and identify the potential sources of the organic components. The major organic compounds of these extracts were derived from natural biogenic and anthropogenic sources. Organic compounds from natural sources, mainly vegetation, were major in samples from outside the city of Riyadh and included n-alkanes, n-alkanoic acids, n- alkanols, methyl alkanoates, and sterols. Anthropogenic inputs were significant in the fine particles of soil and sand samples collected from populated areas of the city. They consisted mainly of n-alkanes, hopanes, UCM (from vehicular emissions), and plasticizers (from discarded plastics, e.g., shopping bags). Carbohydrates had high concentrations in all samples and indicate sources from decomposed cellulose fibers and/or the presence of viable microbiota such as bacteria and fungi.

Outdoor recreation in forest policy and legislation

DEFF Research Database (Denmark)

Mann, Carsten; Pouta, Eija; Gentin, Sandra

2010-01-01

in the field of outdoor recreation, and reveal similarities, differences, gaps and future needs. Among the main findings is a contradiction between the expressed political importance of outdoor recreation at the national level, and the absence of binding commitments for action. The majority of the countries...... surveyed recognise and express outdoor recreation in some form of political and/or legislative way. However, recreation monitoring or measurements are rarely mentioned in relevant policies or acts at the national, regional or local level, perhaps due to a l ack of political will or resources. The analysis...

People participation in natural outdoors recreation activities and its ...

African Journals Online (AJOL)

... of the visitors believe natural outdoor recreation in the south-west of the country ... These identified benefits of Natural Outdoors Recreational in the course of the ... promotion, employment, urban aesthetic, healthy livings and improve tourism ... outdoor recreation centres to augment medical service in improving life span ...

Mass concentration and ion composition of coarse and fine particles in an urban area in Beirut: effect of calcium carbonate on the absorption of nitric and sulfuric acids and the depletion of chloride

Directory of Open Access Journals (Sweden)

H. Kouyoumdjian

2006-01-01

Full Text Available Levels of coarse (PM10-2.5 and fine (PM2.5 particles were determined between February 2004 and January 2005 in the city of Beirut, Lebanon. While low PM mass concentrations were measured in the rainy season, elevated levels were detected during sand storms originating from Arabian desert and/or Africa. Using ATR-FTIR and IC, it was shown that nitrate, sulfate, carbonate and chloride were the main anionic constituents of the coarse particles, whereas sulfate was mostly predominant in the fine particles in the form of (NH42SO4. Ammonium nitrate was not expected to be important because the medium was defined as ammonium poor. In parallel, the cations Ca2+ and Na+ dominated in the coarse, and NH4+, Ca2+ and Na+ in the fine particles. Coarse nitrate and sulfate ions resulted from the respective reactions of nitric and sulfuric acid with a relatively high amount of calcium carbonate. Both CaCO3 and Ca(NO32 crystals identified by ATR-FTIR in the coarse particles were found to be resistant to soaking in water for 24 h but became water soluble when they were formed in the fine particles suggesting, thereby, different growth and adsorption phenomena. The seasonal variational study showed that nitrate and sulfate ion concentrations increased in the summer due to the enhancement of photochemical reactions which facilitated the conversion of NO2 and SO2 gases into NO3- and SO42-, respectively. While nitrate was mainly due to local heavy traffic, sulfates were due to local and long-range transport phenomena. Using the air mass trajectory HYSPLIT model, it was found that the increase in the sulfate concentration correlated with wind vectors coming from Eastern and Central Europe. Chloride levels, on the other hand, were high when wind originated from the sea and low during sand storms. In addition to sea salt, elevated levels of chloride were also attributed to waste mass burning in proximity to the site. In comparison to other neighboring Mediterranean

Pengaruh Outdoor Learning Terhadap Kemampuan Berpikir Kritis Matematis Siswa

Directory of Open Access Journals (Sweden)

Prima Cristi Crismono

2017-12-01

Full Text Available Tujuan penelitian ini untuk mengetahui pengaruh Outdoor Learning terhadap kemampuan berpikir kritis matematis siswa. Hipotesis pada penelitian ini adalah Outdoor Learning berpengaruh dalam meningkatkan kemampuan berpikir kritis matematis siswa. Mengacu pada teori perkembangan kognitifnya penggunaan Outdoor Learning dengan memanfaatkan lingkungan sekitar pada media pembelajaran dan semua aktifitas belajar yang dilakukan oleh siswa di bawah pengawasan dan bimbingan guru. Penggunaan sumber belajar yang bersifat kontektual mampu mengembangkan kemampuan berpikir kritis matematis siswa. Data penelitian dapat diperoleh dengan menggunakan tes yang terdiri dari seperangkat soal uraian untuk mengukur dan mengetahui  kemampuan  awal  matematika  berupa  kemampuan  berpikir  kritis siswa. Hasil analisis pengaruh penerapan metode Outdoor Learning terhadap kemampuan berpikir kritis matematis siswa yang telah dilakukan diketahui bahwa terdapat pengaruh positif penerapan metode Outdoor Learning terhadap kemampuan berpikir kritis matematis siswa. Kesimpulan dari peneitian ini adalah metode Outdoor learning berpengaruh terhadap kemampuan berpikir kritis matematis siswa.

Outdoor recreation

Science.gov (United States)

J. M. Bowker; Ashley Askew; H. Ken Cordell; John C. Bergstrom

2013-01-01

Key FindingsBy 2060, the number of southern adults participating in each of 10 different popular outdoor recreation activities is projected to increase. Depending on future demographic, economic, land use, and population changes, the activity demonstrating the least growth in participants is hunting (8–25 percent). The activity projected to...

Interaction of fine sediment with alluvial streambeds

Science.gov (United States)

Jobson, Harvey E.; Carey, William P.

1989-01-01

More knowledge is needed about the physical processes that control the transport of fine sediment moving over an alluvial bed. The knowledge is needed to design rational sampling and monitoring programs that assess the transport and fate of toxic substances in surface waters because the toxics are often associated with silt- and clay-sized particles. This technical note reviews some of the past research in areas that may contribute to an increased understanding of the processes involved. An alluvial streambed can have a large capacity to store fine sediments that are extracted from the flow when instream concentrations are high and it can gradually release fine sediment to the flow when the instream concentrations are low. Several types of storage mechanisms are available depending on the relative size distribution of the suspended load and bed material, as well as the flow hydraulics. Alluvial flow tends to segregate the deposited material according to size and density. Some of the storage locations are temporary, but some can store the fine sediment for very long periods of time.

Mechanical strength development of mortars containing volcanic scoria-based binders with different fineness

Directory of Open Access Journals (Sweden)

Aref M. al-Swaidani

2016-06-01

Full Text Available The benefits of using natural pozzolan as cement replacement are often associated with shortcomings such as the need to moist-curing for longer time and a reduction of strength at early ages. The objective of the study is to investigate the influence of binder fineness on the mechanical strength development of scoria-based binder mortars. In the study, mortar specimens have been produced with four types of binder: one plain Portland cement (control and three scoria-based binders with three replacement levels: 25%, 30% and 35%, respectively. All scoria-based binders have been inter-ground into four different Blaine fineness: 2400, 3200, 4200 and 5100 cm2/g. The development of the compressive and flexural tensile strength of all mortar specimens with curing time has been investigated. The effects of the Blaine fineness of the scoria-based blended cement on the compressive and flexural strengths of mortar have been evaluated at curing ages of 2, 7, 28 and 90 days, respectively. Particle size distribution measured by a laser diffractometer has been considered in the study. Test results revealed that there is a decrease in strength with increasing amounts of scoria. In addition, there was found an increase in strength with increasing the Blaine fineness values. No direct relationship between Blaine and particle size distribution was observed. Effects of Blaine fineness on some physical properties of blended cements such as water demand, setting times and soundness have also been investigated. Further, an estimation equation for strength development incorporating the effects of fineness measured either by Blaine or by particle size distribution has been derived by the authors.

Thermal Perception in the Mediterranean Area: Comparing the Mediterranean Outdoor Comfort Index (MOCI to Other Outdoor Thermal Comfort Indices

Directory of Open Access Journals (Sweden)

Iacopo Golasi

2016-07-01

Full Text Available Outdoor thermal comfort is an essential factor of people’s everyday life and deeply affects the habitability of outdoor spaces. However the indices used for its evaluation were usually developed for indoor environments assuming still air conditions and absence of solar radiation and were only later adapted to outdoor spaces. For this reason, in a previous study the Mediterranean Outdoor Comfort Index (MOCI was developed, which is an empirical index able to estimate the thermal perception of people living in the Mediterranean area. In this study it was compared numerically (by using the data obtained through a field survey with other selected thermal indices. This comparison, performed in terms of Spearman’s rho correlation coefficient, association Gamma, percentage of correct predictions and cross-tabulation analysis, led to identify the MOCI as the most suitable index to examine outdoor thermal comfort in the interested area. As a matter of fact it showed a total percentage of correct predictions of 35.5%. Good performances were reported even in thermophysiological indices as the Physiological Equivalent Temperature (PET and Predicted Mean Vote (PMV. Moreover it was revealed that adaptation and acclimatization phenomena tend to have a certain influence as well.

Evaluating Suspended Particles Concentration of the Inside and Outside Air of the Classroom and Its Influencing Factors in Middle schools and High Schools of Yazd

Directory of Open Access Journals (Sweden)

MH Ehrampoosh

2015-11-01

Full Text Available Abstract Introduction: Airborne pollution in such public environments as schools has adverse health effects on pupils and teachers who spend a noticeable amount of time in the school. Therefore, this study aimed to measure the suspended particles concentration of indoor and outdoor air of Yazd schools as well as to determine the influencing parameters on the pollution intensity. Methods: This analytical cross-sectional study was conducted in 20 middle-schools and high schools of males and females in winter of 2013. The environmental aerosol monitoring device, (HAZ-DUST EPAM5000 model was used to measure the concentration of PM1, PM2.5 and PM10. The study data were analyzed via applying correlation, simple linear regression and means comparison tests. Moreover, the study results were compared with the standards of World health organization(WHO and Environmental Health Organization(EPA. Results: The mean concentration of PM10, PM2.5 and PM1 in indoor class air was reported higher compared to the outdoor air. The indoor and outdoor air quality of schools in terms of Air Quality Index9 (AQI Calculator indicated an average condition for PM10, and an unhealthy condition for PM2.5 in regard with the vulnerable groups. A significant relationship was detected between indoor and outdoor air concentration particles (P<0.05. The mean indoor per outdoor air particles ratio (I/O was 1.68, 1.31, 1.46 respectively for PM10, PM2.5, PM1. Conclusion: The study findings revealed a significant relationship between indoor and outdoor suspended particle concentration demonstrating the particles penetration into the classrooms. Therefore, utilizing appropriate air conditioner systems are regarded effective in order to mitigate indoor class pollution.  

Microwave background anisotropy and decaying-particle models for a flat universe

International Nuclear Information System (INIS)

Vittorio, N.; Silk, J.

1985-01-01

The fine-scale anisotropy of the cosmic microwave background radiation, induced by primordial scale-invariant adiabatic density fluctuations, has been studied in flat cosmological models dominated by relativistic particles from the recent decay of a massive relic-particle species. We find that, if the relic-particle species consists of massive, unstable neutrinos, there is appreciable, and probably excessive, fine-scale anisotropy in the cosmic microwave background