Iron homeostatis and oxidative stress in idiopathic pulmonary alveolar proteinosis: a case-control study

EPA Science Inventory

ABSTRACT: BACKGROUND: Lung injury caused by both inhaled dusts and infectious agents depends on increased availability of iron and metal-catalyzed oxidative stress. Because inhaled particles, such as silica, and certain infections can cause secondary pulmonary alveolar proteinosi...

Predictors of microbial agents in dust and respiratory health in the Ecrhs.

PubMed

Tischer, Christina; Zock, Jan-Paul; Valkonen, Maria; Doekes, Gert; Guerra, Stefano; Heederik, Dick; Jarvis, Deborah; Norbäck, Dan; Olivieri, Mario; Sunyer, Jordi; Svanes, Cecilie; Täubel, Martin; Thiering, Elisabeth; Verlato, Giuseppe; Hyvärinen, Anne; Heinrich, Joachim

2015-05-02

Dampness and mould exposure have been repeatedly associated with respiratory health. However, less is known about the specific agents provoking or arresting health effects in adult populations. We aimed to assess predictors of microbial agents in mattress dust throughout Europe and to investigate associations between microbial exposures, home characteristics and respiratory health. Seven different fungal and bacterial parameters were assessed in mattress dust from 956 adult ECRHS II participants in addition to interview based home characteristics. Associations between microbial parameters and the asthma score and lung function were examined using mixed negative binomial regression and linear mixed models, respectively. Indoor dampness and pet keeping were significant predictors for higher microbial agent concentrations in mattress dust. Current mould and condensation in the bedroom were significantly associated with lung function decline and current mould at home was positively associated with the asthma score. Higher concentrations of muramic acid were associated with higher mean ratios of the asthma score (aMR 1.37, 95%CI 1.17-1.61). There was no evidence for any association between fungal and bacterial components and lung function. Indoor dampness was associated with microbial levels in mattress dust which in turn was positively associated with asthma symptoms.

Pharmacologic properties of brewery dust extracts in vitro.

PubMed

Schachter, E N; Zuskin, E; Rienzi, N; Goswami, S; Castranova, V; Whitmer, M; Siegel, P

2001-06-01

To study the effects of extracts of brewery dust on isolated guinea pig tracheal smooth muscle in vitro. Parallel pharmacologic intervention on guinea pig tracheal rings that were obtained from the same animal. Mount Sinai School of Medicine, Department of Pulmonary Medicine. The isolated guinea pig tracheal tissue of 18 guinea pigs. Pretreatment of guinea pig rings by mediator-modifying agents before challenge with the brewery dust extracts. The effect of brewery dust extracts on isolated guinea pig tracheal smooth muscle was studied using water-soluble extracts of dust obtained from brewery materials, including hops, barley, and brewery yeast. Dust extracts were prepared as a 1:10 (wt/vol) aqueous solution. Dose-related contractions of nonsensitized guinea pig tracheas were demonstrated using these extracts. The dust extracts contained significant quantities of bacterial components (eg, endotoxin and n-formyl-methionyl-leucyl-phenylalanine), but these agents were not thought to contribute directly to the constrictor effect of the dusts. Pharmacologic studies were performed by pretreating guinea pig tracheal tissue with the following drugs known to modulate smooth muscle contraction: atropine; indomethacin; pyrilamine; LY171883; nordihydroguaiaretic acid; captopril; thiorphan; verapamil; and TMB8. The constrictor effects of the dust extracts were inhibited by a wide variety of agents, the patterns of which depended on the dust extract. Atropine consistently and strikingly reduced the contractile effects of these extracts. These observations may suggest an interaction of the extracts with parasympathetic nerves or, more directly, with muscarinic receptors. The inhibition of contraction by the blocking of other mediators was less effective and varied with the dust extract. We suggest that brewery dust extracts cause a dose-related airway smooth muscle constriction by nonimmunologic mechanisms involving a variety of airway mediators and, possibly, cholinergic receptors. This effect is not dependent on presensitization of the guinea pigs.

Leachability of Cr(VI) and other metals from asphalt composites with addition of filter dust.

PubMed

Vahcic, Mitja; Milacic, Radmila; Mladenovic, Ana; Murko, Simona; Zuliani, Tea; Zupancic, Marija; Scancar, Janez

2008-12-01

The potential use of filter dust in asphalt composites for road construction was investigated. Filter dust contains high concentrations of metals, of which Cr(VI) and Pb are leached with water. Compact and ground asphalt composites with addition of 2% of filter dust by mass were studied. In order to evaluate their environmental impact, leachability tests were performed using water and salt water as leaching agents. The concentrations of Cr(VI) and Pb were determined in leachates over a time period of 182 days. The results indicated that Pb was not leached with leaching agents from asphalt composites. Cr(VI) was also not leached with leaching agents from compact asphalt composites. However, in ground asphalt composites, Cr(VI) was leached with water in concentrations up to 220 microg L(-1) and in salt water up to 150 microg L(-1). From the physico-mechanical and environmental aspects, filter dust can be used as a component in asphalt mixtures.

Allergic Responses Induced by a Fungal Biopesticide Metarhizium anisopliae and House Dust Mite are Compared in a Mouse Model

EPA Science Inventory

Biopesticides can be effective in controlling their target pest. However, research regarding mammalian health impacts of these agents has focused on toxicity and pathogenicity, with limited research regarding allergenicity and asthma development. We compared the ability of funga...

Design and development of a dust dispersion chamber to quantify the dispersibility of rock dust.

PubMed

Perera, Inoka E; Sapko, Michael J; Harris, Marcia L; Zlochower, Isaac A; Weiss, Eric S

2016-01-01

Dispersible rock dust must be applied to the surfaces of entries in underground coal mines in order to inert the coal dust entrained or made airborne during an explosion and prevent propagating explosions. 30 CFR. 75.2 states that "… [rock dust particles] when wetted and dried will not cohere to form a cake which will not be dispersed into separate particles by a light blast of air …" However, a proper definition or quantification of "light blast of air" is not provided. The National Institute for Occupational Safety and Health (NIOSH) has, consequently, designed a dust dispersion chamber to conduct quantitative laboratory-scale dispersibility experiments as a screening tool for candidate rock dusts. A reproducible pulse of air is injected into the chamber and across a shallow tray of rock dust. The dust dispersed and carried downwind is monitored. The mass loss of the dust tray and the airborne dust measurements determine the relative dispersibility of the dust with respect to a Reference rock dust. This report describes the design and the methodology to evaluate the relative dispersibility of rock dusts with and without anti-caking agents. Further, the results of this study indicate that the dispersibility of rock dusts varies with particle size, type of anti-caking agent used, and with the untapped bulk density. Untreated rock dusts, when wetted and dried forming a cake that was much less dispersible than the reference rock dust used in supporting the 80% total incombustible content rule.

Copolyimide Surface Modifying Agents for Particle Adhesion Mitigation

NASA Technical Reports Server (NTRS)

Wohl, Christopher J.; Connell, John W.

2011-01-01

Marine biofouling, insect adhesion on aircraft surfaces, microbial contamination of sterile environments, and particle contamination all present unique challenges for which researchers have adopted an array of mitigation strategies. Particulate contamination is of interest to NASA regarding exploration of the Moon, Mars, asteroids, etc.1 Lunar dust compromised seals, clogged filters, abraded visors and space suit surfaces, and was a significant health concern during the Apollo missions.2 Consequently, NASA has instituted a multi-faceted approach to address dust including use of sacrificial surfaces, active mitigation requiring the use of an external energy source, and passive mitigation utilizing materials with an intrinsic resistance to surface contamination. One passive mitigation strategy is modification of a material s surface energy either chemically or topographically. The focus of this paper is the synthesis and evaluation of novel copolyimide materials with surface modifying agents (SMA, oxetanes) enabling controlled variation of surface chemical composition.

Multiyear Simulations of the Martian Water Cycle with the Ames General Circulation Model

NASA Technical Reports Server (NTRS)

Haberle, R. M.; Schaeffer, J. R.; Nelli, S. M.; Murphy, J. R.

2003-01-01

Mars atmosphere is carbon dioxide dominated with non-negligible amounts of water vapor and suspended dust particles. The atmospheric dust plays an important role in the heating and cooling of the planet through absorption and emission of radiation. Small dust particles can potentially be carried to great altitudes and affect the temperatures there. Water vapor condensing onto the dust grains can affect the radiative properties of both, as well as their vertical extent. The condensation of water onto a dust grain will change the grain s fall speed and diminish the possibility of dust obtaining high altitudes. In this capacity, water becomes a controlling agent with regard to the vertical distribution of dust. Similarly, the atmosphere s water vapor holding capacity is affected by the amount of dust in the atmosphere. Dust is an excellent green house catalyst; it raises the temperature of the atmosphere, and thus, its water vapor holding capacity. There is, therefore, a potentially significant interplay between the Martian dust and water cycles. Previous research done using global, 3-D computer modeling to better understand the Martian atmosphere treat the dust and the water cycles as two separate and independent processes. The existing Ames numerical model will be employed to simulate the relationship between the Martian dust and water cycles by actually coupling the two cycles. Water will condense onto the dust, allowing the particle's radiative characteristics, fall speeds, and as a result, their vertical distribution to change. Data obtained from the Viking, Mars Pathfinder, and especially the Mars Global Surveyor missions will be used to determine the accuracy of the model results.

Research on air sprays and unique foam application methods. Phase II report. Laboratory investigation of foam systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1982-06-01

The objective of this study is to assess the effectiveness of air sprays and foam systems for dust control on longwall double-drum shearer faces. Laboratory testing has been conducted using foam systems and promising results have been obtained. Upon Bureau approval, underground testing will be scheduled to assess the effectiveness of foam systems under actual operating conditions. Laboratory testing of air sprays is being conducted at present. This report presents the results of the laboratory testing of foam systems. Specifically, the results obtained on the evaluation of selected foaming agents are presented, the feasibility investigation of flushing foam through themore » shearer-drum are demonstrated, and conceptual layout of the foam system on the shearer is discussed. The laboratory investigation of the selected foaming agents reveal that the Onyx Microfoam, Onyx Maprosyl and DeTer Microfoam foaming agents have higher expansion ratios compared to the others tested. Flushing foam through the shearer drum is entirely feasible and could be a viable technique for dust suppression on longwall faces.« less

CASH--an innovative approach to sustainable OSH improvement at workplace.

PubMed

Pingle, S; Shanbhag, S

2006-01-01

Occupational health department of a large private enterprise located in India launched Project CASH--Change Agents for Safety and Health, at manufacturing units of the enterprise to bring about a positive change in work environment and improvement in work practices to reduce occupational health risk. Multidisciplinary teams of change agents were constituted and were given intensive training inputs. Reduction in exposure to noise, dust and heat stress were identified as specific objectives after a baseline survey of the work environment. Occupational safety and health knowledge and training was imparted to all field personnel to improve their work practices and attitudes. The focus of the actions was on engineering control measures and process engineering changes necessary for workplace improvement. Noise levels were reduced by an average of more than 9dBA in most of the top ten high noise locations. Out of two locations identified for dust exposure, one was fully eliminated and dust levels at other location were significantly reduced. Heat stress was reduced in all three identified locations with an average reduction of more than 3 degrees C in WBGT levels. Thus, final evaluation of workplace environments revealed significant reduction in exposure to all identified agents, viz noise, dust and heat fulfilling the project objectives. Educating and empowering the team led to reduction of occupational health risks in the work environment. There was positive attitudinal and behavioural change in safety and occupational health awareness & practices among employees. The monetary savings resulting from improvements far outweighed the investments. Success of this pilot project was followed up with further similar projects and their number has grown in geometric proportion for the last three years indicating the sustainability of the project.

Carrier Battle Group (CVBG) Homeporting in the Puget Sound Area, Washington State. Volume 1. Chapters 1-12.

DTIC Science & Technology

1986-11-01

Various setting agents have been used to treat industrial wastes and flue gas desulfurization sludges. These include cement, lime, kiln dust, blast furnace...will determine the type of leachate control strategy that can be successfully implemented. Potential leachate control strategies include site selection...AND ADDRESS 10. PROGRAM ELEMENT, PROJECT, TASK same AREA & WORK UNIT NUMBERS 1I. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE U.S. Army Corps

Lung cancer risk among workers in the construction industry: results from two case-control studies in Montreal.

PubMed

Lacourt, Aude; Pintos, Javier; Lavoué, Jérôme; Richardson, Lesley; Siemiatycki, Jack

2015-09-22

Given the large number of workers in the construction industry, it is important to derive accurate and valid estimates of cancer risk, and in particular lung cancer risk. In most previous studies, risks among construction workers were compared with general populations including blue and white collar workers. The main objectives of this study were to assess whether construction workers experience excess lung cancer risk, and whether exposure to selected construction industry exposures carries excess risks. We wished to address these objectives within the sub-population of blue collar workers. Two case-control studies were conducted in Montreal. Combined, they included 1593 lung cancer cases and 1427 controls, of whom 1304 cases and 1081 controls had been blue collar workers. Detailed lifetime job histories were obtained and translated by experts into histories of exposure to chemical agents. The two key analyses were to estimate odds ratio (OR) estimates of lung cancer risk: a) for all blue-collar construction workers compared with other blue-collar workers, and b) for construction workers exposed to each of 20 exposure agents found in the construction industry compared with construction workers unexposed to those agents. All analyses were conducted using unconditional logistic regression adjusted for socio-demographic factors and smoking history. The OR for all construction workers combined was 1.11 (95 % CI: 0.90-1.38), based on 381 blue collar construction workers. Analyses of specific exposures were hampered by small numbers and imprecise estimates. While none of 20 occupational agents examined was significantly associated with lung cancer, the following agents manifested non-significantly elevated ORs: asbestos, silica, Portland cement, soil dust, calcium oxide and calcium sulfate. Compared with other blue collar workers, there was only a slight increased risk of lung cancer for subjects who ever held an occupation in the construction industry. The analyses of agents within the construction industry produced imprecise estimates of risk, but nevertheless pointed to some plausible associations. Excess risks for asbestos and silica were in line with previous knowledge. The possible excess risks with the other inorganic dusts require further corroboration.

Acaricidal activities of some essential oils and their monoterpenoidal constituents against house dust mite, Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

PubMed Central

Saad, El-Zemity; Hussien, Rezk; Saher, Farok; Ahmed, Zaitoon

2006-01-01

The acaricidal activities of fourteen essential oils and fourteen of their major monoterpenoids were tested against house dust mites Dermatophagoides pteronyssinus. Five concentrations were used over two different time intervals 24 and 48 h under laboratory conditions. In general, it was noticed that the acaricidal effect based on LC 50 of either essential oils or monoterpenoids against the mite was time dependant. The LC 50 values were decreased by increasing of exposure time. Clove, matrecary, chenopodium, rosemary, eucalyptus and caraway oils were shown to have high activity. As for the monoterpenoids, cinnamaldehyde and chlorothymol were found to be the most effective followed by citronellol. This study suggests the use of the essential oils and their major constituents as ecofriendly biodegradable agents for the control of house dust mite, D. pteronyssinus. PMID:17111463

Acaricidal activities of some essential oils and their monoterpenoidal constituents against house dust mite, Dermatophagoides pteronyssinus (Acari: Pyroglyphidae).

PubMed

Saad, El-Zemity; Hussien, Rezk; Saher, Farok; Ahmed, Zaitoon

2006-12-01

The acaricidal activities of fourteen essential oils and fourteen of their major monoterpenoids were tested against house dust mites Dermatophagoides pteronyssinus. Five concentrations were used over two different time intervals 24 and 48 h under laboratory conditions. In general, it was noticed that the acaricidal effect based on LC(50) of either essential oils or monoterpenoids against the mite was time dependant. The LC(50) values were decreased by increasing of exposure time. Clove, matrecary, chenopodium, rosemary, eucalyptus and caraway oils were shown to have high activity. As for the monoterpenoids, cinnamaldehyde and chlorothymol were found to be the most effective followed by citronellol. This study suggests the use of the essential oils and their major constituents as ecofriendly biodegradable agents for the control of house dust mite, D. pteronyssinus.

Evaluation of Dredged Material Disposal Alternatives for U.S. Navy Homeport at Everett, Washington

DTIC Science & Technology

1989-01-01

setting agents have been used to treat hazardous industrial wastes and flue gas desulfurization sludges. These include cement, lime, kiln dust, fly...the type of leachate control strategy , if any, that is appropriate. Table 5 provides a summary of leachate contaminant concentrations for use in... strategy that can be implemented. Potential leachate con- trol strategies include site selection, site controls (both chemical and phys- ical), and

Indoor air pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gold, D.R.

1992-06-01

This article summarizes the health effects of indoor air pollutants and the modalities available to control them. The pollutants discussed include active and passive exposure to tobacco smoke; combustion products of carbon monoxide; nitrogen dioxide; products of biofuels, including wood and coal; biologic agents leading to immune responses, such as house dust mites, cockroaches, fungi, animal dander, and urine; biologic agents associated with infection such as Legionella and tuberculosis; formaldehyde; and volatile organic compounds. An approach to assessing building-related illness and tight building' syndrome is presented. Finally, the article reviews recent data on hospital-related asthma and exposures to potential respiratorymore » hazards such as antineoplastic agents, anesthetic gases, and ethylene oxide.88 references.« less

Optimization of food waste hydrolysis in leach bed coupled with methanogenic reactor: effect of pH and bulking agent.

PubMed

Xu, Su Yun; Lam, Hoi Pui; Karthikeyan, O Parthiba; Wong, Jonathan W C

2011-02-01

The effects of pH and bulking agents on hydrolysis/acidogenesis of food waste were studied using leach bed reactor (LBR) coupled with methanogenic up-flow anaerobic sludge blanket (UASB) reactor. The hydrolysis rate under regulated pH (6.0) was studied and compared with unregulated one during initial experiment. Then, the efficacies of five different bulking agents, i.e. plastic full particles, plastic hollow sphere, bottom ash, wood chip and saw dust were experimented under the regulated pH condition. Leachate recirculation with 50% water replacement was practiced throughout the experiment. Results proved that the daily leachate recirculation with pH control (6.0) accelerated the hydrolysis rate (59% higher volatile fatty acids) and methane production (up to 88%) compared to that of control without pH control. Furthermore, bottom ash improved the reactor alkalinity, which internally buffered the system that improved the methane production rate (0.182 l CH(4)/g VS(added)) than other bulking agents. Copyright © 2010 Elsevier Ltd. All rights reserved.

The role of the sand in chemical warfare agent exposure among Persian Gulf War veterans: Al Eskan disease and "dirty dust".

PubMed

Korényi-Both, A L; Svéd, L; Korényi-Both, G E; Juncer, D J; Korényi-Both, A L; Székely, A

2000-05-01

The purpose of this paper is to inquire into the relationship between Al Eskan disease and the probable exposure to chemical warfare agents by Persian Gulf War veterans. Al Eskan disease, first reported in 1991, compromises the body's immunological defense and is a result of the pathogenic properties of the extremely fine, dusty sand located in the central and eastern region of the Arabian peninsula. The disease manifests with localized expression of multisystem disorder. Signs and symptoms of Al Eskan disease have been termed by the news media "Persian Gulf syndrome." The dust becomes a warfare agent when toxic chemicals are microimpregnated into inert particles. The "dirty dust" concept, that the toxicity of an agent could be enhanced by absorption into inactive particles, dates from World War I. A growing body of evidence shows that coalition forces have encountered Iraqi chemical warfare in the theater of operation/Persian Gulf War to a much greater extent than early U.S. Department of Defense information had indicated. Veterans of that war were exposed to chemical warfare agents in the form of direct (deliberate) attacks by chemical weapons, such as missiles and mines, and indirect (accidental) contamination from demolished munition production plants and storage areas, or otherwise. We conclude that the microimpregnated sand particles in the theater of operation/Persian Gulf War depleted the immune system and simultaneously acted as vehicles for low-intensity exposure to chemical warfare agents and had a modifying-intensifying effect on the toxicity of exposed individuals. We recommend recognition of a new term, "dirty sand," as a subcategory of dirty dust/dusty chemical warfare agents. Our ongoing research efforts to investigate the health impact of chemical warfare agent exposure among Persian Gulf War veterans suggest that Al Eskan disease is a plausible and preeminent explanation for the preponderance of Persian Gulf War illnesses.

Histamine in cereal dusts

PubMed Central

Nicholls, P. J.

1970-01-01

Nicholls, P. J. (1970).Brit. J. industr. Med.,27, 179-180. Histamine in cereal dusts. It has been found that workers exposed to cereal grain dusts may experience acute mild respiratory distress. An attempt has been made to explain this observation by examining the pharmacological activity of aqueous extracts of several cereal dusts from the holds of cargo ships. Histamine, but no other active agent, was found in the samples. It is unlikely that the concentration of histamine in these dusts is sufficient to cause respiratory distress in dockers unloading cereal grain cargoes. PMID:5428638

Gene expression profiling of the effects of organic dust in lung epithelial and THP-1 cells reveals inductive effects on inflammatory and immune response genes

PubMed Central

Loose, David S.; Gottipati, Koteswara R.; Natarajan, Kartiga; Mitchell, Courtney T.

2016-01-01

The intensification and concentration of animal production operations expose workers to high levels of organic dusts in the work environment. Exposure to organic dusts is a risk factor for the development of acute and chronic respiratory symptoms and diseases. Lung epithelium plays important roles in the control of immune and inflammatory responses to environmental agents to maintain lung health. To better understand the effects of organic dust on lung inflammatory responses, we characterized the gene expression profiles of A549 alveolar and Beas2B bronchial epithelial and THP-1 monocytic cells influenced by exposure to poultry dust extract by DNA microarray analysis using Illumina Human HT-12 v4 Expression BeadChip. We found that A549 alveolar and Beas2B bronchial epithelial and THP-1 cells responded with unique changes in the gene expression profiles with regulation of genes encoding inflammatory cytokines, chemokines, and other inflammatory proteins being common to all the three cells. Significantly induced genes included IL-8, IL-6, IL-1β, ICAM-1, CCL2, CCL5, TLR4, and PTGS2. Validation by real-time qRT-PCR, ELISA, Western immunoblotting, and immunohistochemical staining of lung sections from mice exposed to dust extract validated DNA microarray results. Pathway analysis indicated that dust extract induced changes in gene expression influenced functions related to cellular growth and proliferation, cell death and survival, and cellular development. These data show that a broad range of inflammatory mediators produced in response to poultry dust exposure can modulate lung immune and inflammatory responses. This is the first report on organic dust induced changes in expression profiles in lung epithelial and THP-1 monocytic cells. PMID:26884459

Dust control research for SEI. [Space Exploration Initiative

NASA Technical Reports Server (NTRS)

Kennedy, Kriss J.; Harris, Jeffrey R.

1992-01-01

A study, at NASA Johnson Space Center, of dust control requirements for surface habitats has focused on identification of the dust problem, identifying dust control techniques and dust control technology areas requiring research development. This research was performed for the Surface Habitats and Construction (SHAC) technology area. Dust control consists of two problems: (1) how to keep it out of the habitat; and (2) once the habitat or airlock is contaminated with dust, how to collect it. This paper describes the dust environment, the Apollo experience and dust control methods used, future EVA operational considerations, and dust control concepts for surface habitats.

A case-control study of the relationship between the risk of colon cancer in men and exposures to occupational agents.

PubMed

Goldberg, M S; Parent, M E; Siemiatycki, J; Désy, M; Nadon, L; Richardson, L; Lakhani, R; Latreille, B; Valois, M F

2001-06-01

We conducted a population-based case-control study in Montreal, Canada, to explore associations between hundreds of occupational circumstances and several cancer sites, including colon. We interviewed 497 male patients with a pathologically confirmed diagnosis of colon cancer, 1514 controls with cancers at other sites, and 533 population-based controls. Detailed job histories and relevant potential confounding variables were obtained, and the job histories were translated by a team of chemists and industrial hygienists into a history of occupational exposures. We found that there was reasonable evidence of associations for men employed in nine industry groups (adjusted odds ranging from 1.1 to 1.6 per a 10-year increase in duration of employment), and in 12 job groups (OR varying from 1.1 to 1.7). In addition, we found evidence of increased risks by increasing level of exposures to 21 occupational agents, including polystyrene (OR for "substantial" exposure (OR(subst)) = 10.7), polyurethanes (OR(subst) = 8.4), coke dust (OR(subst) = 5.6), mineral oils (OR(subst) = 3.3), polyacrylates (OR(subst) = 2.8), cellulose nitrate (OR(subst) = 2.6), alkyds (OR(subst) = 2.5), inorganic insulation dust (OR(subst) = 2.3), plastic dusts (OR(subst) = 2.3), asbestos (OR(subst) = 2.1), mineral wool fibers (OR(subst) = 2.1), glass fibers (OR(subst) = 2.0), iron oxides (OR(subst) = 1.9), aliphatic ketones (OR(subst) = 1.9), benzene (OR(subst) = 1.9), xylene (OR(subst) = 1.9), inorganic acid solutions (OR(subst) = 1.8), waxes, polishes (OR(subst) = 1.8), mononuclear aromatic hydrocarbons (OR(subst) = 1.6), toluene (OR(subst) = 1.6), and diesel engine emissions (OR(subst) = 1.5). Not all of these effects are independent because some exposures occurred contemporaneously with others or because they referred to a group of substances. We have uncovered a number of occupational associations with colon cancer. For most of these agents, there are no published data to support or refute our observations. As there are few accepted risk factors for colon cancer, we suggest that new occupational and toxicologic studies be undertaken focusing on the more prevalent substances reported herein. Copyright 2001 Wiley-Liss, Inc.

Arsenic, tobacco smoke, and occupation: associations of multiple agents with lung and bladder cancer.

PubMed

Ferreccio, Catterina; Yuan, Yan; Calle, Jacqueline; Benítez, Hugo; Parra, Roxana L; Acevedo, Johanna; Smith, Allan H; Liaw, Jane; Steinmaus, Craig

2013-11-01

Millions of people worldwide are exposed to arsenic in drinking water, and many are likely coexposed to other agents that could substantially increase their risks of arsenic-related cancer. We performed a case-control study of multiple chemical exposures in 538 lung and bladder cancer cases and 640 controls in northern Chile, an area with formerly high drinking water arsenic concentrations. Detailed information was collected on lifetime arsenic exposure, smoking, secondhand smoke, and other known or suspected carcinogens, including asbestos, silica, and wood dust. Very high lung and bladder cancer odds ratios (ORs), and evidence of greater than additive effects, were seen in people exposed to arsenic concentrations >335 µg/L and who were tobacco smokers (OR = 16, 95% confidence interval = 6.5-40 for lung cancer; and OR = 23 [8.2-66] for bladder cancer; Rothman Synergy Indices = 4.0 [1.7-9.4] and 2.0 [0.92-4.5], respectively). Evidence of greater than additive effects were also seen in people coexposed to arsenic and secondhand tobacco smoke and several other known or suspected carcinogens, including asbestos, silica, and wood dust. These findings suggest that people coexposed to arsenic and other known or suspected carcinogens have very high risks of lung or bladder cancer.

Assessing the impact of national level interventions on workplace respiratory disease in the UK: part 2--regulatory activity by the Health and Safety Executive.

PubMed

Stocks, S J; McNamee, R; Turner, S; Carder, M; Agius, R M

2013-07-01

To investigate whether interventions implemented by the UK Health and Safety Executive addressing exposure to isocyanate-based spray paints in motor vehicle repair (MVR), flour dust in craft bakeries, rosin-based solder flux fume (RBSFF) in the electronics industry, metalworking fluids and wood dust coincided with a decline in incidence of work-related short latency respiratory disease (SLRD) or asthma in the target groups. Changes in the incidence of SLRD reported to a UK-based surveillance scheme were compared using a longitudinal, negative binomial regression model with β distributed random effects. An interrupted time series design was used and comparisons according to inclusion or exclusion in the target group were made by including a statistical interactions expressed as a ratio of incidence rate ratios (RIRRs) in the model. The incidence of SLRD attributed to flour dust significantly increased relative to all other agents (RIRR: 1.10; 95% CI 1.06 to 1.16) whereas SLRD attributed to RBSFF significantly declined relative to all other agents (0.94; 0.90 to 0.99). No significant changes in the incidence of SLRD attributed to wood dust (1.03; 0.91 to 1.16) or spray paints (1.03; 0.95 to 1.11) relative to all other agents were observed. A higher proportion of reports originated from the industries targeted by the intervention for RBSFF (65/107; 61%) than spray painting (27/93; 27%) or wood dust (16/42; 38%). These data support a beneficial effect of interventions to reduce exposure to RBSFF but an increase in SLRD attributed to flour dust may indicate increased exposure or increased awareness of the problem.

Importance of indoor dust biological ultrafine particles in the pathogenesis of chronic inflammatory lung diseases

PubMed Central

Kim, Yoon-Keun; Kang, Tae Soo; Kim, You-Young

2017-01-01

The role of infectious agents in the etiology of inflammatory diseases once believed to be non-infectious is increasingly being recognized. Many bacterial components in the indoor dust can evoke inflammatory lung diseases. Bacteria secrete nanometer-sized vesicles into the extracellular milieu, so-called extracellular vesicles (EV). which are pathophysiologically related to inflammatory diseases. Microbiota compositions in the indoor dust revealed the presence of both Gram-negative and Gram-positive bacteria. Escherichia coli is a model organism of Gram-negative Enterobacteriaceae. The repeated inhalation of E. coli-derived EVs caused neutrophilic inflammation and emphysema in a dose-dependent manner. The emphysema induced by E. coli-derived EVs was partially eliminated by the absence of Interferon-gamma or interleukin-17, suggesting that Th1 and/or Th17 cell responses are important in the emphysema development. Meanwhile, the repeated inhalation of Staphylococcus aureus-derived EVs did not induce emphysema, although they induced neutrophilic inflammation in the lung. In terms of microbial EV compositions in the indoor dust, genera Pseudomonas, Acinetobacter, Enterobacter, and Staphylococcus were dominant. As for the clinical significance of sensitization to EVs in the indoor dust, EV sensitization was closely associated with asthma, chronic obstructive pulmonary disorder (COPD), and lung cancer. These data indicate that biological ultrafine particles in the indoor dust, which are mainly composed of microbial EVs, are important in the pathogenesis of chronic lung diseases associated with neutrophilic inflammation. Taken together, microbial EVs in the indoor dust are an important diagnostic and therapeutic target for the control of chronic lung diseases, such as asthma, COPD, and lung cancer. PMID:29161804

Importance of indoor dust biological ultrafine particles in the pathogenesis of chronic inflammatory lung diseases.

PubMed

Yang, Jinho; Kim, Yoon-Keun; Kang, Tae Soo; Jee, Young-Koo; Kim, You-Young

2017-01-01

The role of infectious agents in the etiology of inflammatory diseases once believed to be non-infectious is increasingly being recognized. Many bacterial components in the indoor dust can evoke inflammatory lung diseases. Bacteria secrete nanometer-sized vesicles into the extracellular milieu, so-called extracellular vesicles (EV). which are pathophysiologically related to inflammatory diseases. Microbiota compositions in the indoor dust revealed the presence of both Gram-negative and Gram-positive bacteria. Escherichia coli is a model organism of Gram-negative Enterobacteriaceae. The repeated inhalation of E. coli-derived EVs caused neutrophilic inflammation and emphysema in a dose-dependent manner. The emphysema induced by E. coli-derived EVs was partially eliminated by the absence of Interferon-gamma or interleukin-17, suggesting that Th1 and/or Th17 cell responses are important in the emphysema development. Meanwhile, the repeated inhalation of Staphylococcus aureus-derived EVs did not induce emphysema, although they induced neutrophilic inflammation in the lung. In terms of microbial EV compositions in the indoor dust, genera Pseudomonas, Acinetobacter, Enterobacter, and Staphylococcus were dominant. As for the clinical significance of sensitization to EVs in the indoor dust, EV sensitization was closely associated with asthma, chronic obstructive pulmonary disorder (COPD), and lung cancer. These data indicate that biological ultrafine particles in the indoor dust, which are mainly composed of microbial EVs, are important in the pathogenesis of chronic lung diseases associated with neutrophilic inflammation. Taken together, microbial EVs in the indoor dust are an important diagnostic and therapeutic target for the control of chronic lung diseases, such as asthma, COPD, and lung cancer.

Effect of occupational exposures on lung cancer susceptibility: a study of gene-environment interaction analysis.

PubMed

Malhotra, Jyoti; Sartori, Samantha; Brennan, Paul; Zaridze, David; Szeszenia-Dabrowska, Neonila; Świątkowska, Beata; Rudnai, Peter; Lissowska, Jolanta; Fabianova, Eleonora; Mates, Dana; Bencko, Vladimir; Gaborieau, Valerie; Stücker, Isabelle; Foretova, Lenka; Janout, Vladimir; Boffetta, Paolo

2015-03-01

Occupational exposures are known risk factors for lung cancer. Role of genetically determined host factors in occupational exposure-related lung cancer is unclear. We used genome-wide association (GWA) data from a case-control study conducted in 6 European countries from 1998 to 2002 to identify gene-occupation interactions and related pathways for lung cancer risk. GWA analysis was performed for each exposure using logistic regression and interaction term for genotypes, and exposure was included in this model. Both SNP-based and gene-based interaction P values were calculated. Pathway analysis was performed using three complementary methods, and analyses were adjusted for multiple comparisons. We analyzed 312,605 SNPs and occupational exposure to 70 agents from 1,802 lung cancer cases and 1,725 cancer-free controls. Mean age of study participants was 60.1 ± 9.1 years and 75% were male. Largest number of significant associations (P ≤ 1 × 10(-5)) at SNP level was demonstrated for nickel, brick dust, concrete dust, and cement dust, and for brick dust and cement dust at the gene-level (P ≤ 1 × 10(-4)). Approximately 14 occupational exposures showed significant gene-occupation interactions with pathways related to response to environmental information processing via signal transduction (P < 0.001 and FDR < 0.05). Other pathways that showed significant enrichment were related to immune processes and xenobiotic metabolism. Our findings suggest that pathways related to signal transduction, immune process, and xenobiotic metabolism may be involved in occupational exposure-related lung carcinogenesis. Our study exemplifies an integrative approach using pathway-based analysis to demonstrate the role of genetic variants in occupational exposure-related lung cancer susceptibility. Cancer Epidemiol Biomarkers Prev; 24(3); 570-9. ©2015 AACR. ©2015 American Association for Cancer Research.

[Backgrounds for assessing occupational exposure to crystalline silica dust in Poland and worldwide].

PubMed

Maciejewska, Aleksandra

2007-01-01

Crystalline silica is an agent harmful to human health, and quite frequently present in occupational environments. Occupational groups exposed to crystalline silica dust include mostly workers of the mineral and coal mining as well as metallurgical, chemical and construction industries. In the European Union (EU), the number of those exposed to this agent is estimated at over 2 million persons. In Poland, the number of people employed under conditions of excessive silica dust exposure exceeds 50 thousand. The assessment of occupational exposure to crystalline silica comprises several steps: primarily workplace determinations, quantitative sample analyses and comparisons of the obtained results with admissible values. This work describes a set of instruments that enables direct comparison of the study results with admissible values binding in almost 40 countries. It also highlights the consequences resulting from the classification of quartz and cristobalite, the most common forms of crystalline silica, as carcinogens by the International Agency for Research on Cancer (IARC). A survey of air sampling and dust determination methods used in various countries to measure airborne dust concentrations of crystalline silica in occupational environments are presented along with relevant tables. The GESTIS data base, specifying the methods considered by EU as suitable for measuring and assessing harmful agents, was used as the selection criterion. Particular attention was paid to the methods used to determine crystalline silica; the effect of analytical methods applied, sample preparation procedures, and reference materials on the results of determinations was also analyzed. Main parameters of method validation, such as detection and determination limits, and precision of the analysis were compared.

30 CFR 72.630 - Drill dust control at underground areas of underground mines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... dust control at underground areas of underground mines. (a) Dust resulting from drilling in rock shall... condition. Dust collectors approved under Part 33—Dust Collectors for Use in Connection with Rock Drilling... the purpose of this section. (c) Water control. Water used to control dust from drilling rock shall be...

30 CFR 72.630 - Drill dust control at underground areas of underground mines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... dust control at underground areas of underground mines. (a) Dust resulting from drilling in rock shall... condition. Dust collectors approved under Part 33—Dust Collectors for Use in Connection with Rock Drilling... the purpose of this section. (c) Water control. Water used to control dust from drilling rock shall be...

Agricultural lung diseases.

PubMed Central

Kirkhorn, S R; Garry, V F

2000-01-01

Agriculture is considered one of the most hazardous occupations. Organic dusts and toxic gases constitute some of the most common and potentially disabling occupational and environmental hazards. The changing patterns of agriculture have paradoxically contributed to both improved working conditions and increased exposure to respiratory hazards. Animal confinement operations with increasing animal density, particularly swine confinement, have contributed significantly to increased intensity and duration of exposure to indoor air toxins. Ongoing research has implicated bacterial endotoxins, fungal spores, and the inherent toxicity of grain dusts as causes of upper and lower airway inflammation and as immunologic agents in both grain and animal production. Animal confinement gases, particularly ammonia and hydrogen sulfide, have been implicated as additional sources of respiratory irritants. It has become evident that a significant percentage of agricultural workers have clinical symptoms associated with long-term exposure to organic dusts and animal confinement gases. Respiratory diseases and syndromes, including hypersensitivity pneumonitis, organic dust toxic syndrome, chronic bronchitis, mucous membrane inflammation syndrome, and asthmalike syndrome, result from ongoing acute and chronic exposures. In this review we focus upon the emerging respiratory health issues in a changing agricultural economic and technologic environment. Environmental and occupational hazards and exposures will be emphasized rather than clinical diagnosis and treatment. Methods of prevention, from both engineering controls and personal respiratory perspectives, are also addressed. PMID:10931789

Inerting of magnesium dust cloud with Ar, N2 and CO2.

PubMed

Li, G; Yuan, C M; Fu, Y; Zhong, Y P; Chen, B Z

2009-10-15

Experiments were conducted on the inerting of magnesium dust with N(2), CO(2), and Ar. Comparing the maximum explosion pressure, maximum rate of pressure rise, and limiting oxygen concentration with different inertants, it was determined that Ar is not the best inert gas under all conditions as commonly believed. N(2) was more effective than Ar as an inertant. CO(2) provided more inerting effect than either Ar and N(2) in low magnesium dust concentrations, although explosibility was increased at higher dust concentrations. Both N(2) and CO(2) as inerting agents showed higher LOC values than Ar. These results indicated that N(2) is a more economical inerting gas than Ar for the tested coarse magnesium dust.

Pantoea agglomerans: a mysterious bacterium of evil and good. Part II--Deleterious effects: Dust-borne endotoxins and allergens--focus on grain dust, other agricultural dusts and wood dust.

PubMed

Dutkiewicz, Jacek; Mackiewicz, Barbara; Lemieszek, Marta Kinga; Golec, Marcin; Skórska, Czesława; Góra-Florek, Anna; Milanowski, Janusz

2016-01-01

Pantoea agglomerans, a Gram-negative bacterium developing in a variety of plants as epiphyte or endophyte is particularly common in grain and grain dust, and has been identified by an interdisciplinary group from Lublin, eastern Poland, as a causative agent of work-related diseases associated with exposure to grain dust and other agricultural dusts. The concentration of P. agglomerans in grain as well as in the settled grain and flour dust was found to be high, ranging from 10(4)-10(8) CFU/g, while in the air polluted with grain or flour dust it ranged from 10(3)-10(5) CFU/m(3) and formed 73.2-96% of the total airborne Gram-negative bacteria. The concentration of P. agglomerans was also relatively high in the air of the facilities processing herbs and other plant materials, while it was lower in animal farms and in wood processing facilities. Pantoea agglomerans produces a biologically-potent endotoxin (cell wall lipopolysaccharide, LPS). The significant part of this endotoxin occurs in dusts in the form of virus-sized globular nanoparticles measuring 10-50 nm that could be described as the 'endotoxin super-macromolecules'. A highly significant relationship was found (R=0.804, P=0.000927) between the concentration of the viable P. agglomerans in the air of various agricultural and wood industry settings and the concentration of bacterial endotoxin in the air, as assessed by the Limulus test. Although this result may be interfered by the presence of endotoxin produced by other Gram-negative species, it unequivocally suggests the primary role of the P. agglomerans endotoxin as an adverse agent in the agricultural working environment, causing toxic pneumonitis (ODTS). Numerous experiments by the inhalation exposure of animals to various extracts of P. agglomerans strains isolated from grain dust, including endotoxin isolated with trichloroacetic acid (LPS-TCA), endotoxin nanoparticles isolated in sucrose gradient (VECN), and mixture of proteins and endotoxin obtained by extraction of bacterial mass in saline (CA-S), showed the ability of these extracts to evoke inflammatory and fibrotic changes in the lungs, to stimulate alveolar macrophages to produce superoxide anion (O2(-)), interleukin-1 (IL-1) and chemotactic factors for other macrophages and neutrophils, and to increase the pulmonary concentrations of toll-like receptors and chemokines. The most potent properties showed the CA-S which may be attributed to the allergenic properties of P. agglomerans proteins enhanced by the presence of the autologous endotoxin. The results of these experiments are in accord with the clinical studies which revealed a high reactivity of the agricultural and grain industry workers to allergenic extracts of P. agglomerans, and the presence in these populations of hypersensitivity pneumonitis and asthma cases caused by this bacterium. P. agglomerans has been also identified as a potential causative agent of allergic dermatitis in farmers and of allergic pulmonary disorders in cattle. In conclusion, similar to the cotton industry, also in the grain industry and in agriculture, Pantoea agglomerans should be regarded as one of the major causative agents of work-related diseases, caused by the adverse effects of protein allergens and endotoxin produced by this bacterium.

[Groups and sources of yeasts in house dust].

PubMed

Glushakova, A M; Zheltikova, T M; Chernov, I Iu

2004-01-01

House dust contains bacteria, mycelial fungi, microarthropods, and yeasts. The house dust samples collected in 25 apartments in Moscow and the Moscow region were found to contain yeasts belonging to the genera Candida, Cryptococcus, Debaryomyces, Rhodotorula, Sporobolomyces, and Trichosporon. The most frequently encountered microorganisms were typical epiphytic yeasts, such as Cryptococcus diffluens and Rhodotorula mucilaginosa, which are capable of long-term preservation in an inactive state. The direct source of epiphytic yeasts occurring in the house dust might be the indoor plants, which were contaminated with these yeasts, albeit to a lesser degree than outdoor plants. Along with the typical epiphytic yeasts, the house dust contained the opportunistic yeast pathogens Candida catenulata, C. guillermondii, C. haemulonii, C. rugosa, and C. tropicalis, which are known as the causal agents of candidiasis. We failed to reveal any correlation between the abundance of particular yeast species in the house dust, residential characteristics, and the atopic dermatitis of the inhabitants.

Duststones on Mars: source, transport, deposition and erosion

USGS Publications Warehouse

Bridges, Nathan T.; Muhs, Daniel R.; Grotzinger, John P.; Milliken, Ralph E.

2012-01-01

Dust is an abundant material on Mars, and there is strong evidence that it is a contributor to the rock record as “duststone,” analogous in many ways to loess on Earth. Although a common suite of dust formation mechanisms has operated on the two planets, fundamental differences in environments and geologic histories have resulted in vastly different weighting functions, causing distinct depositional styles and erosional mechanisms. On Earth, dust is derived predominantly from glacial grinding and, in nonglacial environments, by other processes, such as volcanism, eolian abrasion, and fluvial comminution. Hydrological and biological processes convert dust accumulations to loess deposits. Active hydrology also acts to clean dust from the atmosphere and convert loess into soil or erode it entirely. On Mars, glacial production of dust has been minor, with most fine particles probably produced from ancient volcanic, impact, and fluvial processes. Dust is deposited under arid conditions in which aggregate growth and cementation are the stabilizing agents. Thick accumulations result in duststone.

30 CFR 72.630 - Drill dust control at underground areas of underground mines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... condition. Dust collectors approved under Part 33—Dust Collectors for Use in Connection with Rock Drilling...) Ventilation control. To adequately control dust from drilling rock, the air current shall be so directed that...

30 CFR 72.630 - Drill dust control at underground areas of underground mines.

Code of Federal Regulations, 2011 CFR

2011-07-01

... condition. Dust collectors approved under Part 33—Dust Collectors for Use in Connection with Rock Drilling...) Ventilation control. To adequately control dust from drilling rock, the air current shall be so directed that...

30 CFR 57.9315 - Dust control.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Dust control. 57.9315 Section 57.9315 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....9315 Dust control. Dust shall be controlled at muck piles, material transfer points, crushers, and on...

30 CFR 57.9315 - Dust control.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Dust control. 57.9315 Section 57.9315 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....9315 Dust control. Dust shall be controlled at muck piles, material transfer points, crushers, and on...

Induction of histamine release in vitro from rat peritoneal mast cells by extracts of grain dust.

PubMed Central

Warren, C P; Holford-Strevens, V

1986-01-01

The ability of extracts of grain dust and wheat to induce histamine release from rat peritoneal cells was investigated. Some grain dusts, with a high endotoxin content, were found to produce cytotoxic histamine release. Extract of wheat dust, with a low endotoxin release, produced noncytotoxic histamine release from peritoneal cells but not from purified mast cells. This reaction was dependent on the presence of phosphatidyl serine. The agent did not appear to be a lectin because histamine release was not enhanced by passive sensitization of mast cells with IgE. The activity occurred only over a narrow range of concentrations of the extract of wheat. The cause was unclear. PMID:2423321

Exposure to Fibres, Crystalline Silica, Silicon Carbide and Sulphur Dioxide in the Norwegian Silicon Carbide Industry

PubMed Central

Føreland, S.; Bye, E.; Bakke, B.; Eduard, W.

2008-01-01

Objectives: The aim of this study was to assess personal exposure to fibres, crystalline silica, silicon carbide (SiC) and sulphur dioxide in the Norwegian SiC industry. Methods: Approximately 720 fibre samples, 720 respirable dust samples and 1400 total dust samples were collected from randomly chosen workers from the furnace, processing and maintenance departments in all three Norwegian SiC plants. The respirable dust samples were analysed for quartz, cristobalite and non-fibrous SiC content. Approximately 240 sulphur dioxide samples were collected from workers in the furnace department. Results: The sorting operators from all plants, control room and cleaning operators in Plant A and charger, charger/mix and payloader operators in Plant C had a geometric mean (GM) of fibre exposure above the Norwegian occupational exposure limit (OEL) (0.1 fibre cm−3). The cleaner operators in Plant A had the highest GM exposure to respirable quartz (20 μg m−3). The charger/mix operators in Plant C had the highest GM exposure to respirable cristobalite (38 μg m−3) and the refinery crusher operators in Plant A had the highest GM exposure to non-fibrous SiC (0.65 mg m−3). Exposure to the crystalline silica and non-fibrous SiC was generally low and between 0.4 and 2.1% of the measurements exceeded the OELs. The cleaner operators in Plant A had the highest GM exposure to respirable dust (1.3 mg m−3) and total dust (21 mg m−3). GM exposures for respirable dust above the Norwegian SiC industry-specific OEL of 0.5 mg m−3 were also found for refinery crusher operators in all plants and mix, charger, charger/mix and sorting operators in Plant C. Only 4% of the total dust measurements exceeded the OEL for nuisance dust of (10 mg m−3). Exposure to sulphur dioxide was generally low. However, peaks in the range of 10–100 p.p.m. were observed for control room and crane operators in Plants A and B and for charger and charger/mix operators in Plant C. Conclusion: Workers in the SiC industry are exposed to a mixture of several agents including SiC fibres, quartz, cristobalite, non-fibrous SiC and sulphur dioxide. Exposure levels were generally below the current Norwegian OELs; however, high exposure to fibres and respirable dust still occurs in the furnace department. PMID:18550624

30 CFR 58.620 - Drill dust control.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Drill dust control. 58.620 Section 58.620... SAFETY AND HEALTH HEALTH STANDARDS FOR METAL AND NONMETAL MINES Miscellaneous § 58.620 Drill dust control. Holes shall be collared and drilled wet, or other effective dust control measures shall be used, when...

30 CFR 58.620 - Drill dust control.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Drill dust control. 58.620 Section 58.620... SAFETY AND HEALTH HEALTH STANDARDS FOR METAL AND NONMETAL MINES Miscellaneous § 58.620 Drill dust control. Holes shall be collared and drilled wet, or other effective dust control measures shall be used, when...

30 CFR 58.620 - Drill dust control.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Drill dust control. 58.620 Section 58.620... SAFETY AND HEALTH HEALTH STANDARDS FOR METAL AND NONMETAL MINES Miscellaneous § 58.620 Drill dust control. Holes shall be collared and drilled wet, or other effective dust control measures shall be used, when...

30 CFR 58.620 - Drill dust control.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Drill dust control. 58.620 Section 58.620... SAFETY AND HEALTH HEALTH STANDARDS FOR METAL AND NONMETAL MINES Miscellaneous § 58.620 Drill dust control. Holes shall be collared and drilled wet, or other effective dust control measures shall be used, when...

30 CFR 58.620 - Drill dust control.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Drill dust control. 58.620 Section 58.620... SAFETY AND HEALTH HEALTH STANDARDS FOR METAL AND NONMETAL MINES Miscellaneous § 58.620 Drill dust control. Holes shall be collared and drilled wet, or other effective dust control measures shall be used, when...

Epidemiology and disease control in everyday beef practice.

PubMed

Larson, R L

2008-08-01

It is important for food animal veterinarians to understand the interaction among animals, pathogens, and the environment, in order to implement herd-specific biosecurity plans. Animal factors such as the number of immunologically protected individuals influence the number of individuals that a potential pathogen is able to infect, as well as the speed of spread through a population. Pathogens differ in their virulence and contagiousness. In addition, pathogens have various methods of transmission that impact how they interact with a host population. A cattle population's environment includes its housing type, animal density, air quality, and exposure to mud or dust and other health antagonists such as parasites and stress; these environmental factors influence the innate immunity of a herd by their impact on immunosuppression. In addition, a herd's environment also dictates the "animal flow" or contact and mixing patterns of potentially infectious and susceptible animals. Biosecurity is the attempt to keep infectious agents away from a herd, state, or country, and to control the spread of infectious agents within a herd. Infectious agents (bacteria, viruses, or parasites) alone are seldom able to cause disease in cattle without contributing factors from other infectious agents and/or the cattle's environment. Therefore to develop biosecurity plans for infectious disease in cattle, veterinarians must consider the pathogen, as well as environmental and animal factors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, E.E.; Welty, B.D.

Molten wax shows considerable promise as a fixative and dust control agent in demolition of radioactively contaminated facilities. Sticky molten wax, modified with special surfactants and wetting agents, is capable of not only coating materials but also penetrating into friable or dusty materials and making them incapable of becoming airborne during demolition. Wax also shows significant promise for stabilization of waste residuals that may be contained in buildings undergoing demolition. Some of the building materials that have been tested to date include concrete, wood, sheet rock, fiber insulation, lime, rock, and paper. Protective clothing, clay, sand, sulfur, and bentonite claymore » have been tested as surrogates for certain waste materials that may be encountered during building demolition. The paper describes several potential applications of molten wax for dust control in demolition of radioactive contaminated facilities. As a case-study, this paper describes a research test performed for a pipeline closure project being completed by the Idaho Cleanup Project at the Idaho National Laboratory. The project plans to excavate and remove a section of buried Duriron drain piping containing highly radioactive and friable and 'flighty' waste residuals. A full-scale pipeline mockup containing simulated waste was buried in sand to simulate the direct buried subsurface condition of the subject piping. The pipeline was pre-heated by drawing hot air through the line with a HEPA vacuum blower unit. Molten wax was pumped into the line and allowed to cool. The line was then broken apart in various places to evaluate the permeation performance of the wax. The wax fully permeated all the surrogate materials rendering them non-friable with a consistency similar to modeling clay. Based on the performance during the mockup, it is anticipated that the wax will be highly effective in controlling the spread of radiological contamination during pipe demolition activities. (authors)« less

Experimental study on effects of drilling parameters on respirable dust production during roof bolting operations.

PubMed

Jiang, Hua; Luo, Yi; McQuerrey, Joe

2018-02-01

Underground coalmine roof bolting operators exhibit a continued risk for overexposure to airborne levels of respirable coal and crystalline silica dust from the roof drilling operation. Inhaling these dusts can cause coal worker's pneumoconiosis and silicosis. This research explores the effect of drilling control parameters, specifically drilling bite depth, on the reduction of respirable dust generated during the drilling process. Laboratory drilling experiments were conducted and results demonstrated the feasibility of this dust control approach. Both the weight and size distribution of the dust particles collected from drilling tests with different bite depths were analyzed. The results showed that the amount of total inhalable and respirable dust was inversely proportional to the drilling bite depth. Therefore, control of the drilling process to achieve proper high-bite depth for the rock can be an important approach to reducing the generation of harmful dust. Different from conventional passive engineering controls, such as mist drilling and ventilation approaches, this approach is proactive and can cut down the generation of respirable dust from the source. These findings can be used to develop an integrated drilling control algorithm to achieve the best drilling efficiency as well as reducing respirable dust and noise.

[Biological contamination in office buildings related to ventilation/air conditioning system].

PubMed

Bródka, Karolina; Sowiak, Małgorzata; Kozajda, Anna; Cyprowski, Marcin; Irena, Szadkowska-Stańczyk

2012-01-01

Indoor air is contaminated with microorganisms coming from both the atmospheric air and sources present in premises. The aim of this study was to analyze the concentrations of biological agents in office buildings, dependending on ventilation/air conditioning system and season. The study covered office buildings (different in the system of ventila-tion/air conditioning). Air samples for assessing the levels of inhalable dust, endotoxins and (1-->3)-beta-D-glucans, were taken at the selected stationary points of each building during summer and winter. The air was sampled for 6 h, using portable sets consisting of the GilAir 5 pump and the head filled with a filter of fiber glass. The samples for the presence of airborne bacteria and fungi were collected twice during the day using the impaction method. Average concentrations of inhalable dust, bacteria, fungi, endotoxins and (1-->3)-beta-D-glucans in office premises were 0.09 mg/m3, 6.00 x 10(2) cfu/m3, 4.59 x 10(1) cfu/m3, 0.42 ng/m3 and 3.91 ng/m3, respectively. Higher concentrations of the investigated agents were found in summer. In premises with air conditioning concentrations of airborne fungi, (1-->3)-beta-D-glucans and inhalable dust were significantly lower in winter. In summer the trend was reverse except for (1-->3)-beta-D-glucans. Concentrations of biological agents were affected by the season and the presence of air conditioning. Concentrations of inhalable dust, bacteria, fungi, endotoxins and (1-->3)-beta-D-glucans, observed inside the office buildings, were significantly higher in summer than in winter. The presence of the air conditioning system modified in various ways the levels of biological agents. Its influence was greater on the concentration of fungi and (1-->3)-beta-D-glucans than on that of bacteria and endotoxins.

[Appropriate dust control measures for jade carving operations].

PubMed

Liu, Jiang; Wang, Qiushui; Liu, Guangquan

2002-12-01

To provide the appropriate dust control measures for jade carving operations. Dust concentrations in the workplace were measured according to GB/T 5748-85. Ventilation system of dust control were measured according to GB/T 16157-1996. Dust particle size distributions for different sources and particle size fraction collecting efficiencies of the dust collectors were measured with WY-1 in-stack 7 stage cascade impactors. On the basis of adopting wet process in the carving operations, local exhaust ventilation system for dust control was installed, which included: the special designed slot exhaust hoods with hood face velocity of 2.5 m/s and exhaust volume of 600 m3/h. The pipe sizes were determined according to the air volume passing through the pipe and the reasonable air velocities. Impinging scrubber or bag filter dust collector were selected to treat the dust laden air from the local exhaust ventilation system, which gave a total collecting efficiency of 97% for impinging scrubber and 98% for bag filter; The type of fan and its size were selected according to the total air volume of the ventilation system and maximum total pressure needed for the longest pipe line plus the pressure drop of the dust collector. Practical application showed that, after installation and use of the appropriate dust control measures, the dust concentrations in the workplaces could meet or nearly meet the national hygienic standard and the dust laden air at the local exhaust ventilation system could meet the national emission standard.

30 CFR 72.630 - Drill dust control at underground areas of underground mines.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Drill dust control at underground areas of underground mines. 72.630 Section 72.630 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT... dust control at underground areas of underground mines. (a) Dust resulting from drilling in rock shall...

Polarization and studies of evolved star mass loss

NASA Astrophysics Data System (ADS)

Sargent, Benjamin; Srinivasan, Sundar; Riebel, David; Meixner, Margaret

2012-05-01

Polarization studies of astronomical dust have proven very useful in constraining its properties. Such studies are used to constrain the spatial arrangement, shape, composition, and optical properties of astronomical dust grains. Here we explore possible connections between astronomical polarization observations to our studies of mass loss from evolved stars. We are studying evolved star mass loss in the Large Magellanic Cloud (LMC) by using photometry from the Surveying the Agents of a Galaxy's Evolution (SAGE; PI: M. Meixner) Spitzer Space Telescope Legacy program. We use the radiative transfer program 2Dust to create our Grid of Red supergiant and Asymptotic giant branch ModelS (GRAMS), in order to model this mass loss. To model emission of polarized light from evolved stars, however, we appeal to other radiative transfer codes. We probe how polarization observations might be used to constrain the dust shell and dust grain properties of the samples of evolved stars we are studying.

Occupational asthma in the developing and industrialised world: a review.

PubMed

Jeebhay, M F; Quirce, S

2007-02-01

Occupational asthma is the most common occupational lung disease in industrialised countries, and the second most common occupational lung disease reported after pneumoconioses in developing countries. The median proportion of adult cases of asthma attributable to occupational exposure is between 10% and 15%. The population attributable fraction appears to be similar in industrialised and developing countries characterised by rapid industrialisation (13-15%), but lower in less industrialised developing countries (6%). The high-risk occupations and industries associated with the development of occupational asthma vary depending on the dominant industrial sectors in a particular country. High-risk exposure to cleaning agents and pesticide exposure in developing countries appear to be as important as exposure to isocyanates, cereal flour/grain dust, welding fumes, wood dust and, more recently, hairdressing chemicals, commonly reported in industrialised countries. The reported mean annual incidence of occupational asthma in developing countries is less than 2 per 100 000 population, compared to very high rates of up to 18/100 000 in Scandinavian countries. While occupational asthma remains under-recognised, especially in developing countries, it remains poorly diagnosed and managed and inadequately compensated worldwide. Primary and secondary preventive strategies should be directed at controlling workplace exposures, accompanied by intense educational and managerial improvements. Appropriate treatment remains early removal from exposure to ensure that the worker has no further exposure to the causal agent, with preservation of income. However, up to one third of workers with occupational asthma continue to remain exposed to the causative agent or suffer prolonged work disruption, discrimination and risk of unemployment.

Risk in cleaning: chemical and physical exposure.

PubMed

Wolkoff, P; Schneider, T; Kildesø, J; Degerth, R; Jaroszewski, M; Schunk, H

1998-04-23

Cleaning is a large enterprise involving a large fraction of the workforce worldwide. A broad spectrum of cleaning agents has been developed to facilitate dust and dirt removal, for disinfection and surface maintenance. The cleaning agents are used in large quantities throughout the world. Although a complex pattern of exposure to cleaning agents and resulting health problems, such as allergies and asthma, are reported among cleaners, only a few surveys of this type of product have been performed. This paper gives a broad introduction to cleaning agents and the impact of cleaning on cleaners, occupants of indoor environments, and the quality of cleaning. Cleaning agents are usually grouped into different product categories according to their technical functions and the purpose of their use (e.g. disinfectants and surface care products). The paper also indicates the adverse health and comfort effects associated with the use of these agents in connection with the cleaning process. The paper identifies disinfectants as the most hazardous group of cleaning agents. Cleaning agents contain evaporative and non-evaporative substances. The major toxicologically significant constituents of the former are volatile organic compounds (VOCs), defined as substances with boiling points in the range of 0 degree C to about 400 degrees C. Although laboratory emission testing has shown many VOCs with quite different time-concentration profiles, few field studies have been carried out measuring the exposure of cleaners. However, both field studies and emission testing indicate that the use of cleaning agents results in a temporal increase in the overall VOC level. This increase may occur during the cleaning process and thus it can enhance the probability of increased short-term exposure of the cleaners. However, the increased levels can also be present after the cleaning and result in an overall increased VOC level that can possibly affect the indoor air quality (IAQ) perceived by occupants. The variety and duration of the emissions depend inter alia on the use of fragrances and high boiling VOCs. Some building materials appear to increase their VOC emission through wet cleaning and thus may affect the IAQ. Particles and dirt contain a great variety of both volatile and non-volatile substances, including allergens. While the volatile fraction can consist of more than 200 different VOCs including formaldehyde, the non-volatile fraction can contain considerable amounts (> 0.5%) of fatty acid salts and tensides (e.g. linear alkyl benzene sulphonates). The level of these substances can be high immediately after the cleaning process, but few studies have been conducted concerning this problem. The substances partly originate from the use of cleaning agents. Both types are suspected to be airway irritants. Cleaning activities generate dust, mostly by resuspension, but other occupant activities may also resuspend dust over longer periods of time. Personal sampling of VOCs and airborne dust gives higher results than stationary sampling. International bodies have proposed air sampling strategies. A variety of field sampling techniques for VOC and surface particle sampling is listed.

Effect of Simulant Type on the Absorptance and Emittance of Dusted Thermal Control Surfaces in a Simulated Lunar Environment

NASA Technical Reports Server (NTRS)

Gaier, James R.

2010-01-01

During the Apollo program the effects of lunar dust on thermal control surfaces was found to be more significant than anticipated, with several systems overheating due to deposition of dust on them. In an effort to reduce risk to future missions, a series of tests has been initiated to characterize the effects of dust on these surfaces, and then to develop technologies to mitigate that risk. Given the variations in albedo across the lunar surface, one variable that may be important is the darkness of the lunar dust, and this study was undertaken to address that concern. Three thermal control surfaces, AZ-93 white paint and AgFEP and AlFEP second surface mirrors were dusted with three different lunar dust simulants in a simulated lunar environment, and their solar absorptivity and thermal emissivity values determined experimentally. The three simulants included JSC 1AF, a darker mare simulant, NU-LHT-1D, a light highlands simulant, and 1:1 mixture of the two. The response of AZ-93 was found to be slightly more pronounced than that of AgFEP. The increased with fractional dust coverage in both types of samples by a factor of 1.7 to 3.3, depending on the type of thermal control surface and the type of dust. The of the AZ-93 decreased by about 10 percent when fully covered by dust, while that of AgFEP increased by about 10 percent. It was found that alpha/epsilon varied by more than a factor of two depending on the thermal control surface and the darkness of the dust. Given that the darkest simulant used in this study may be significantly lighter than the darkest dust that could be encountered on the lunar surface, it becomes apparent that the performance degradation of thermal control surfaces due to dust on the moon will be strongly dependent on the and of the dust in the specific locality.

Effect of Simulant Type on the Absorptance and Emittance of Dusted Thermal Control Surfaces in a Simulated Lunar Environment

NASA Technical Reports Server (NTRS)

Gaier, James R.

2010-01-01

During the Apollo program the effects of lunar dust on thermal control surfaces was found to be more significant than anticipated, with several systems overheating due to deposition of dust on them. In an effort to reduce risk to future missions, a series of tests has been initiated to characterize the effects of dust on these surfaces, and then to develop technologies to mitigate that risk. Given the variations in albedo across the lunar surface, one variable that may be important is the darkness of the lunar dust, and this study was undertaken to address that concern. Three thermal control surfaces, AZ-93 white paint and AgFEP and AlFEP second surface mirrors were dusted with three different lunar dust simulants in a simulated lunar environment, and their integrated solar absorptance ( ) and thermal emittance ( ) values determined experimentally. The three simulants included JSC-1AF, a darker mare simulant, NU-LHT-1D, a light highlands simulant, and 1:1 mixture of the two. The response of AZ-93 was found to be slightly more pronounced than that of AgFEP. The increased with fractional dust coverage in both types of samples by a factor of 1.7 to 3.3, depending on the type of thermal control surface and the type of dust. The of the AZ-93 decreased by about 10 percent when fully covered by dust, while that of AgFEP increased by about 10 percent. It was found that / varied by more than a factor of two depending on the thermal control surface and the darkness of the dust. Given that the darkest simulant used in this study may be lighter than the darkest dust that could be encountered on the lunar surface, it becomes apparent that the performance degradation of thermal control surfaces due to dust on the Moon will be strongly dependent on the and of the dust in the specific locality

Lifetime Occupational Exposure to Dusts, Gases and Fumes Is Associated with Bronchitis Symptoms and Higher Diffusion Capacity in COPD Patients

PubMed Central

Rodríguez, Esther; Ferrer, Jaume; Zock, Jan-Paul; Serra, Ignasi; Antó, Josep M.; de Batlle, Jordi; Kromhout, Hans; Vermeulen, Roel; Donaire-González, David; Benet, Marta; Balcells, Eva; Monsó, Eduard; Gayete, Angel; Garcia-Aymerich, Judith

2014-01-01

Background Occupational exposure to dusts, gases and fumes has been associated with reduced FEV1 and sputum production in COPD patients. The effect of occupational exposure on other characteristics of COPD, especially those reflecting emphysema, has not been studied in these patients. Methods We studied 338 patients hospitalized for a first exacerbation of COPD in 9 Spanish hospitals, obtaining full occupational history in a face-to-face interview; job codes were linked to a job exposure matrix for semi-quantitative estimation of exposure to mineral/biological dust, and gases/fumes for each job held. Patients underwent spirometry, diffusing capacity testing and analysis of gases in stable conditions. Quality of life, dyspnea and chronic bronchitis symptoms were determined with a questionnaire interview. A high- resolution CT scan was available in 133 patients. Results 94% of the patients included were men, with a mean age of 68(8.5) years and a mean FEV1% predicted 52 (16). High exposure to gases or fumes was associated with chronic bronchitis, and exposure to mineral dust and gases/fumes was associated with higher scores for symptom perception in the St. George’s questionnaire. No occupational agent was associated with a lower FEV1. High exposure to all occupational agents was associated with better lung diffusion capacity, in long-term quitters. In the subgroup with CT data, patients with emphysema had 18% lower DLCO compared to those without emphysema. Conclusions In our cohort of COPD patients, high exposure to gases or fumes was associated with chronic bronchitis, and high exposure to all occupational agents was consistently associated with better diffusion capacity in long-term quitters. PMID:24516659

Evaluation of Surface Modification as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

NASA Technical Reports Server (NTRS)

Gaier, James R.; Waters, Deborah L.; Misconin, Robert M.; Banks, Bruce A.; Crowder, Mark

2011-01-01

Three surface treatments were evaluated for their ability to lower the adhesion between lunar simulant dust and AZ93, AlFEP, and AgFEP thermal control surfaces under simulated lunar conditions. Samples were dusted in situ and exposed to a standardized puff of nitrogen gas. Thermal performance before dusting, after dusting, and after part of the dust was removed by the puff of gas, were compared to perform the assessment. None of the surface treatments was found to significantly affect the adhesion of lunar simulants to AZ93 thermal control paint. Oxygen ion beam texturing also did not lower the adhesion of lunar simulant dust to AlFEP or AgFEP. But a workfunction matching coating and a proprietary Ball Aerospace surface treatment were both found to significantly lower the adhesion of lunar simulants to AlFEP and AgFEP. Based on these results, it is recommended that all these two techniques be further explored as dust mitigation coatings for AlFEP and AgFEP thermal control surfaces.

30 CFR 72.620 - Drill dust control at surface mines and surface areas of underground mines.

Code of Federal Regulations, 2011 CFR

2011-07-01

... collared and drilled wet, or other effective dust control measures shall be used, when drilling non-water-soluble material. Effective dust control measures shall be used when drilling water-soluble material. ...

30 CFR 72.620 - Drill dust control at surface mines and surface areas of underground mines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... collared and drilled wet, or other effective dust control measures shall be used, when drilling non-water-soluble material. Effective dust control measures shall be used when drilling water-soluble material. ...

30 CFR 72.620 - Drill dust control at surface mines and surface areas of underground mines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... collared and drilled wet, or other effective dust control measures shall be used, when drilling non-water-soluble material. Effective dust control measures shall be used when drilling water-soluble material. ...

30 CFR 72.620 - Drill dust control at surface mines and surface areas of underground mines.

Code of Federal Regulations, 2014 CFR

2014-07-01

... collared and drilled wet, or other effective dust control measures shall be used, when drilling non-water-soluble material. Effective dust control measures shall be used when drilling water-soluble material. ...

30 CFR 72.620 - Drill dust control at surface mines and surface areas of underground mines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... collared and drilled wet, or other effective dust control measures shall be used, when drilling non-water-soluble material. Effective dust control measures shall be used when drilling water-soluble material. ...

Nurse Case Management and Housing Interventions Reduce Allergen Exposures: The Milwaukee Randomized Controlled Trial

PubMed Central

Breysse, Jill; Wendt, Jean; Dixon, Sherry; Murphy, Amy; Wilson, Jonathan; Meurer, John; Cohn, Jennifer; Jacobs, David E.

2011-01-01

Objective We examined the impact of a combination of home environmental interventions and nurse case management services on total settled dust loadings and on allergen concentrations in the homes of asthmatic children. Methods Using a randomized longitudinal controlled trial study design, we randomly assigned homes of asthmatic children in Milwaukee to either a control (n=64) or an intervention (n=57) group. Control group homes received a visual assessment, education, bed/pillow dust mite encasings, and treatment of lead-based paint hazards. The intervention group received these same services plus nurse case management that included tailored, individual asthma action plans, provision of minor home repairs, home cleaning using special vacuuming and wet washing, and integrated pest management. Dust vacuum samples were collected from measured surface areas of floors in the TV room, kitchen, and child's bedroom at baseline and at three-, six-, and 12-month follow-up visits. Dust loading (mass per surface area) is a means of measuring total dust and the total amount of allergen present. Results For the intervention group, geometric mean dust loadings declined significantly from baseline (39 milligrams per square foot [mg/ft2]) to post-intervention (11 mg/ft2) (p<0.001). Baseline dust loading, treatment group, visit, and season were significant predictors of follow-up dust loadings. Mean post-intervention dust loadings were 72% higher in the control group. The total amount of allergen in settled house dust declined significantly following the intervention because total dust loading declined; the concentration of allergens in settled dust did not change significantly. Conclusion The combination of nurse case management and home environmental interventions promotes collaboration between health and housing professionals and is effective in reducing exposures to allergens in settled dust. PMID:21563716

The HERschel Inventory of the Agents of Galaxy Evolution in the Magellanic Clouds, a HERschel Open Time Key Program

NASA Technical Reports Server (NTRS)

Meixner, Margaret; Panuzzo, P.; Roman-Duval, J.; Engelbracht, C.; Babler, B.; Seale, J.; Hony, S.; Montiel, E.; Sauvage, M.; Gordon, K.;

30 CFR 56.9315 - Dust control.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Dust control. 56.9315 Section 56.9315 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... control. Dust shall be controlled at muck piles, material transfer points, crushers, and on haulage roads...

30 CFR 56.9315 - Dust control.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Dust control. 56.9315 Section 56.9315 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... control. Dust shall be controlled at muck piles, material transfer points, crushers, and on haulage roads...

30 CFR 56.9315 - Dust control.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Dust control. 56.9315 Section 56.9315 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... control. Dust shall be controlled at muck piles, material transfer points, crushers, and on haulage roads...

Proximal detection of chemical warfare agents using PMIRRAS

NASA Astrophysics Data System (ADS)

Petryk, Michael W. P.; Marenco, Armando J.

2010-04-01

Non-contact chemical warfare agent detection has been demonstrated on military painted surfaces using polarization modulation infrared reflection-absorption spectroscopy (PMIRRAS). Notably, VX has been detected on chemical agent resistance coating (CARC) paint at a distance of approximately 10 cm. PMIRRAS does not rely on the presence of chemical vapors and is not affected by many common battlefield interferants such as aerosolized dust, water and diesel vapors, etc., making it highly suitable for use in operational environments.

Allergy-related disorders in the construction industry.

PubMed

Carino, Mauro; Romita, Paolo; Foti, Caterina

2013-01-01

Working conditions in the construction industry have improved in many industrialized countries, but heavy physical work with recurrent exposure to chemical agents, dust, and climatic influences still represents considerable risk for construction workers and may affect their health. The aim of this review is to analyze available data of the literature on allergy-related respiratory and skin disorders with emphasis on a preventive appraisal in order to produce statements and recommendations based on research evidence. The most common agents involved in the construction industry as a cause of occupational asthma (OA) in industrialized countries are isocyanates, wood dust, resins, glues, cobalt, and chromium. Allergic contact dermatitis (ACD) is an immunologic cell-mediated response to a sensitizing agent and the most common sensitizing agents associated with construction workers are epoxy resins, thiurams and thiazoles, and chromates. Medical surveillance must consider individual risk factors such as differences in individual susceptibility and sensitization to agents at workplace. Once work-related disorder is confirmed, adequate fitness for work should be assessed for the worker impaired by health condition. A reliable diagnosis of an index case is a sentinel event that may reveal risks for workers with similar exposure, leading to a revised risk assessment at the workplace that should reduce the risk and prevent further cases.

The effects of wood dusts on the redox status and cell death in mouse macrophages (RAW 264.7) and human leukocytes in vitro.

PubMed

Naarala, J; Kasanen, J-P; Pasanen, P; Pasanen, A-L; Liimatainen, A; Pennanen, S; Liesivuori, J

2003-07-11

Wood dusts are classified as carcinogenic to humans and also produce other toxic, allergic, and acute effects in woodworkers. However, little is known about causative agents in wood dusts and their mechanisms of action. The effects of different tree species and particle size for biological activity were studied. The differences in the production of reactive oxygen species (ROS) and cell death (necrotic and apoptotic) between mouse macrophage (RAW 264.7) cells and human polymorphonuclear leukocytes (PMNL) for pine, birch, and beech dust exposures were investigated in vitro. The pine and birch dust exposure (1-100 microg/ml) produced concentration-dependent ROS production in both the cells, which was one order of magnitude higher with pine dust. The ROS production was faster in human PNML than murine RAW cells. The higher concentrations (500 and/or 1000 microg/ml) decreased ROS formation. With pine and birch dust exposure, this was probably due to the necrotic cell death. The pine dust concentrations of 500 and 1000 microg/ml were cytotoxic to human PMNL. The beech dust exposure activated the ROS production and decreased the cell viability only at the highest concentrations, being least potent of the three dusts. A sign of the apoptotic cell death in the murine RAW cells was observed at the pine dust concentration of 100 microg/ml. The exposure to the birch and beech dusts with a smaller particle size (<5 microm) produced greater ROS production than exposure to the corresponding dust with a wide range of particle sizes. However, changing the particle size did not affect the cell viability. The results indicate that the type of wood dust (tree species and possibly particle size) has a significant impact on the function and viability of phagocytic cells.

Effects of grain dust on lungs prior to and following dust remediation.

PubMed

Pahwa, Punam; Dosman, James A; McDuffie, Helen H

2008-12-01

To determine longitudinal estimates of pulmonary function decline in Canadian grain elevator workers before and after dust control by analyzing data collected from five regions of Canada over 15 years. Declines in forced expired volume in one second and forced vital capacity before and after dust control were estimated by using a generalized estimating equations approach. For grain workers who were in the grain industry for 20 or more years both before and after dust control: the mean annual loss of forced expired volume in one second was greatest among current smoking grain workers followed by ex-smokers and nonsmokers, respectively. Similar results were obtained for forced vital capacity. Grain dust control was effective in reducing decline in the lung function measurements among grain workers in all smoking and exposure categories.

Evaluate fundamental approaches to longwall dust control. Phase III report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babbitt, C.; Bartlett, P.; Kelly, J.

1984-03-31

The overall objective of the contract is to evaluate the effectiveness of available dust control technology for double-drum shearer longwall sections in a coordinated, systematic program at a few longwall test sections and to make the results available to the entire coal mining industry. This program is investigating nine different dust control techniques. These nine subprograms encompass a broad range of dust control measures ranging from administrative controls to new hardware. They span not only presently employed methods but also those recently adopted in the United States and those proposed for the future. This report documents the Phase III effortmore » on each of the subprograms. For clarity, the report is divided in sections by subprogram as follows: Section 2, Subprogram A - passive barriers/spray air movers for dust control; Section 3, Subprogram B - practical aspects of deep cutting; Section 4, Subprogram C - stage loader dust control; Section 5, Subprogram D - longwall automation technology; Section 6, Subprogram E - longwall application of ventilation curtains; Section 7, Subprogram F - reversed drum rotation; Section 8, Subprogram G - reduction of shield generated dust; Section 9, Subprogram H - air canopies for longwalls; and Section 10, Subprogram I - mining practices. 43 figures, 11 tables.« less

Exposure to Inhalable Dust, Endotoxin, and Total Volatile Organic Carbons on Dairy Farms Using Manual and Automated Feeding Systems.

PubMed

Basinas, Ioannis; Cronin, Garvin; Hogan, Victoria; Sigsgaard, Torben; Hayes, James; Coggins, Ann Marie

2017-04-01

Agricultural workers tend to have high exposures to organic dusts which may induce or exacerbate respiratory disorders. Studies investigating the effect of work tasks and farm characteristics on organic dust exposures among farm workers suggest that handling of animal feed is an important exposure determinant; however, the effect of the animal feeding system has not been explored in any detail. To measure the exposure of Irish dairy farmers to inhalable dust, endotoxin, and total volatile organic compounds (TVOCs) during parlour work and to explore whether levels of exposure to these agents depend on the applied feeding system in the farms. Thirty-eight personal exposure measurements were collected from farmers across seven dairy farms. The farms used manual, loft, or semi-automated feeding systems. Information on worker tasks and farm characteristics was collected during the surveys. Associations between exposure concentrations and feeding systems, worker tasks, and other farm characteristics were explored in linear mixed-effect regression models with farmer identity treated as a random effect. Exposure concentrations were variable and had a geometric mean (GM; geometric standard deviation) of 1.5 mg m-3 (1.8) for inhalable dust and 128 EU m-3 (2.5) for endotoxin. More than 50% of the exposure measurements for endotoxin, and organic dust exceeded recommended health-based occupational exposure limits. Endotoxin levels were somewhat lower in farms using semi-automatic feeding systems when compared to those using manual feeding systems but in multivariate regression analysis associations were not statistically significant (β = -0.54, P = 0.4). Performance of activities related to handling and spreading of hay or straw was the strongest determinant for both inhalable dust and endotoxin exposure (β = 0.78, P ≤ 0.001; β = 0.72, P = 0.02, respectively). The level of dust exposure increased also as a consequence of a lower outdoor temperature, and higher ratio of distributed feed per cow (P = 0.01). Stationary measurements of TVOC and CO2 concentrations inside the dairy parlours had a GM of 180 ppb (1.9) and 589 ppb (1.3), respectively. The use of cow teat disinfectants and building ventilation were both strong predictors of TVOC concentrations within parlours. Dairy farm workers can be exposed to high and variable levels of inhalable dust and endotoxin and may be at risk of respiratory disease. Results from this study suggest that exposure control strategies for organic dusts and TVOCs exposures should consider building ventilation and work tasks such as spreading of bedding material, using spray disinfectants and animal feeding. Until effective permanent engineering controls are established farm workers should be encouraged to wear respiratory protective equipment during these tasks. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Effect of ground control mesh on dust sampling and explosion mitigation.

PubMed

Alexander, D W; Chasko, L L

2015-07-01

Researchers from the National Institute for Occupational Safety and Health's Office of Mine Safety and Health Research conducted an assessment of the effects that ground control mesh might have on rock and float coal dust distribution in a coal mine. The increased use of mesh to control roof and rib spall introduces additional elevated surfaces on which rock or coal dust can collect. It is possible to increase the potential for dust explosion propagation if any float coal dust is not adequately inerted. In addition, the mesh may interfere with the collection of representative dust samples when using the pan-and-brush sampling method developed by the U.S. Bureau of Mines and used by the Mine Safety and Health Administration for band sampling. This study estimates the additional coal or rock dust that could accumulate on mesh and develops a means to collect representative dust samples from meshed entries.

Effect of ground control mesh on dust sampling and explosion mitigation

PubMed Central

Alexander, D.W.; Chasko, L.L.

2017-01-01

Researchers from the National Institute for Occupational Safety and Health’s Office of Mine Safety and Health Research conducted an assessment of the effects that ground control mesh might have on rock and float coal dust distribution in a coal mine. The increased use of mesh to control roof and rib spall introduces additional elevated surfaces on which rock or coal dust can collect. It is possible to increase the potential for dust explosion propagation if any float coal dust is not adequately inerted. In addition, the mesh may interfere with the collection of representative dust samples when using the pan-and-brush sampling method developed by the U.S. Bureau of Mines and used by the Mine Safety and Health Administration for band sampling. This study estimates the additional coal or rock dust that could accumulate on mesh and develops a means to collect representative dust samples from meshed entries. PMID:28936000

Global distribution of minerals in arid soils as lower boundary condition in dust models

NASA Astrophysics Data System (ADS)

Nickovic, Slobodan

2010-05-01

Mineral dust eroded from arid soils affects the radiation budget of the Earth system, modifies ocean bioproductivity and influences human health. Dust aerosol is a complex mixture of minerals. Dust mineral composition has several potentially important impacts to environment and society. Iron and phosphorus embedded in mineral aerosol are essential for the primary marine productivity when dust deposits over the open ocean. Dust also acts as efficient agent for heterogeneous ice nucleation and this process is dependent on mineralogical structure of dust. Recent findings in medical geology indicate possible role of minerals to human health. In this study, a new 1-km global database was developed for several minerals (Illite, Kaolinite, Smectite, Calcite, Quartz, Feldspar, Hematite and Gypsum) embedded in clay and silt populations of arid soils. For the database generation, high-resolution data sets on soil textures, soil types and land cover was used. Tin addition to the selected minerals, phosphorus was also added whose geographical distribution was specified from compiled literature and data on soil types. The developed global database was used to specify sources of mineral fractions in the DREAM dust model and to simulate atmospheric paths of minerals and their potential impacts on marine biochemistry and tropospheric ice nucleation.

Mycobacterium abscessus Displays Fitness for Fomite Transmission

PubMed Central

Caceres, Silvia M.; Honda, Jennifer R.; Davidson, Rebecca M.; Epperson, L. Elaine; Strong, Michael; Chan, Edward D.; Nick, Jerry A.

2017-01-01

ABSTRACT Mycobacterium abscessus is a rapidly growing nontuberculous mycobacterium (NTM) increasingly reported in soft tissue infections and chronic lung diseases, including cystic fibrosis. The environmental source of M. abscessus has not been definitively identified, but NTM have been detected in soil and water. To determine the potential of soil-derived M. abscessus as an infectious source, we explored the association, growth, and survival of M. abscessus with defined mineral particulates, including kaolin, halloysite, and silicone dioxide, and house dust as possible M. abscessus fomites. M. abscessus physically associated with particulates, and the growth of M. abscessus was enhanced in the presence of both kaolin and house dust. M. abscessus survived desiccation for 2 weeks but was not viable after 3 weeks. The rate of decline of M. abscessus viability during desiccation was reduced in the presence of house dust. The evidence for enhanced growth and survival of M. abscessus during alternating growth and drying periods suggests that dissemination could occur when in wet or dry environments. These studies are important to understand environmental survival and acquisition of NTM. IMPORTANCE The environmental source of pulmonary Mycobacterium abscessus infections is not known. Fomites are nonliving carriers of infectious agents and may contribute to acquisition of M. abscessus. This study provides evidence that M. abscessus growth is enhanced in the presence of particulates, using kaolin, an abundant natural clay mineral, and house dust as experimental fomites. Moreover, M. abscessus survived desiccation for up to 2 weeks in the presence of house dust, kaolin, and several chemically defined mineral particulates; mycobacterial viability during extended periods of dessication was enhanced by the presence of house dust. The growth characteristics of M. abscessus with particulates suggest that a fomite mechanism of transmission may contribute to M. abscessus acquisition, which may lead to strategies to better control infections by M. abscessus and related organisms. PMID:28754702

The Atlantic Richfield Company Black Thunder mine haul road dust study. [Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxwell, D.R.; Hormel, T.R.; Ives, J.A.

An examination of the effectiveness of various haul road dust control measures was performed at ARCO's Black Thunder Mine near Wright, Wyoming by evaluating both visible observations and quantitative measurements of particle concentrations. In order to evaluate dust control effectiveness both a 300 foot (91.5 meter) and 175 foot (53.4 meter) section of the main coal haul road was selected for testing. The test sections were separated by a 200 foot (61 meter) buffer zone. Each test section was relatively straight and away from interferences from other mine sources. The five haul road treatment test sequences evaluated for control measuremore » effectiveness were: an untreated road segment; water treatment two times per hour; water treatment four times per hour; previously chemically treated segment of haul road (ARCO 2400 dust suppressant); and testing after application of Coherex (10% dilution). By comparing uncontrolled situations with various controlled situations, an estimate of the control efficiency of the dust control measures was determined. Based upon the results of the study a fugitive dust control scheme was selected considering control effectiveness, economics and operational efficiency.« less

The Effect of Simulated Lunar Dust on the Absorptivity, Emissivity, and Operating Temperature on AZ-93 and Ag/FEP Thermal Control Surfaces

NASA Technical Reports Server (NTRS)

Gaier, James R.; Siamidis, John; Panko, Scott R.; Rogers, Kerry J.; Larkin, Elizabeth M. G.

2008-01-01

JSC-1AF lunar simulant has been applied to AZ-93 and AgFEP thermal control surfaces on aluminum or composite substrates in a simulated lunar environment. The temperature of these surfaces was monitored as they were heated with a solar simulator and cooled in a 30 K coldbox. Thermal modeling was used to determine the absorptivity ( ) and emissivity ( ) of the thermal control surfaces in both their clean and dusted states. Then, a known amount of power was applied to the samples while in the coldbox and the steady state temperatures measured. It was found that even a submonolayer of simulated lunar dust can significantly degrade the performance of both white paint and second-surface mirror type thermal control surfaces under these conditions. Contrary to earlier studies, dust was found to affect as well as . Dust lowered the emissivity by as much as 16 percent in the case of AZ-93, and raised it by as much as 11 percent in the case of AgFEP. The degradation of thermal control surface by dust as measured by / rose linearly regardless of the thermal control coating or substrate, and extrapolated to degradation by a factor 3 at full coverage by dust. Submonolayer coatings of dust were found to not significantly change the steady state temperature at which a shadowed thermal control surface will radiate.

Dust Production and Mass Loss in Cool Evolved Stars

NASA Technical Reports Server (NTRS)

Boyer, M. L.

2013-01-01

Following the red giant branch phase and the subsequent core He-burning phase, the low- to intermediate-mass stars (0.8

Assessing the efficacy of a novel temperature and humidity control machine to minimize house dust mite allergen exposure and clinical symptoms in allergic rhinitis children sensitized to dust mites: a pilot study.

PubMed

Manuyakorn, Wiparat; Padungpak, Savitree; Luecha, Orawin; Kamchaisatian, Wasu; Sasisakulporn, Cherapat; Vilaiyuk, Soamarat; Monyakul, Veerapol; Benjaponpitak, Suwat

2015-06-01

House dust mite avoidance is advised in dust mite sensitized patients to decrease the risk to develop allergic symptoms. Maintaining a relative humidity (RH) of less than 50% in households is recommended to prevent dust mite proliferation. To investigate the efficacy of a novel temperature and humidity machine to control the level of dust mite allergens and total nasal symptom score (TNSS) in dust mite sensitized allergic rhinitis children. Children (8-15 years) with dust mite sensitized persistent allergic rhinitis (AR) were enrolled. The temperature and humidity control machine was installed in the bedroom where the enrolled children stayed for 6 months. TNSS was assessed before and every month after machine set up and the level of dust mite allergen (Der p 1 and Der f 1) from the mattress were measured before and every 2 months after machine set up using enzyme-linked immunosorbent assay (ELISA). A total of 7 children were enrolled. Noticeable reduction of Der f 1 was observed as early as 2 months after installing the machine, but proper significant differences appeared 4 months after and remained low until the end of the experiment (p <0.05). Although no correlation was observed between TNSS and the level of dust mite allergens, there was a significant reduction in TNSS at 2 and 4 months (p <0.05) and 70% of the patients were able to stop using their intranasal corticosteroids by the end of the experiment. The level of house dust mite in mattresses was significantly reduced after using the temperature and humidity control machine. This machine may be used as an effective tool to control clinical symptoms of dust mite sensitized AR children.

Behavioral Responses of the Common Bed Bug, Cimex lectularius, to Insecticide Dusts.

PubMed

Agnew, John L; Romero, Alvaro

2017-08-08

Bed bugs have reemerged recently as a serious and growing problem not only in North America but in many parts of the world. These insects have become the most challenging pest to control in urban environments. Residual insecticides are the most common methods used for bed bug control; however, insecticide resistance limits the efficacy of treatments. Desiccant dusts have emerged as a good option to provide a better residual effect for bed bug control. Several studies have focused on determining the efficacy of dust-based insecticides against bed bugs. However, behavioral responses of bed bugs to insecticide dusts could influence their efficacy. The behavioral responses of bed bugs to six insecticide dusts commonly used in the United States were evaluated with an advanced video tracking technique (Ethovision). Bed bugs took longer to make first contact with areas treated with the diatomaceous earth (DE)-based products MotherEarth D and Alpine than pyrethroid, pyrethrins or silica gel based products, DeltaDust, Tempo 1% Dust and CimeXa, respectively. Lower visitation rates of bed bugs were recorded for areas treated with MotherEarth D, Alpine and CimeXa than that of DeltaDust, Tempo 1% Dust, and Tri-Die Silica + Pyrethrum Dust. Bed bugs spent less time in areas treated with Tri-Die Dust, CimeXa, Alpine, and MotherEarth D than DeltaDust and Tempo 1% Dust, and they exhibited a reduction in locomotor parameters when crawling on areas treated with CimeXa and Alpine. The implications of these responses to bed bug control are discussed.

Behavioral Responses of the Common Bed Bug, Cimex lectularius, to Insecticide Dusts

PubMed Central

Agnew, John L.; Romero, Alvaro

2017-01-01

Bed bugs have reemerged recently as a serious and growing problem not only in North America but in many parts of the world. These insects have become the most challenging pest to control in urban environments. Residual insecticides are the most common methods used for bed bug control; however, insecticide resistance limits the efficacy of treatments. Desiccant dusts have emerged as a good option to provide a better residual effect for bed bug control. Several studies have focused on determining the efficacy of dust-based insecticides against bed bugs. However, behavioral responses of bed bugs to insecticide dusts could influence their efficacy. The behavioral responses of bed bugs to six insecticide dusts commonly used in the United States were evaluated with an advanced video tracking technique (Ethovision). Bed bugs took longer to make first contact with areas treated with the diatomaceous earth (DE)-based products MotherEarth D and Alpine than pyrethroid, pyrethrins or silica gel based products, DeltaDust, Tempo 1% Dust and CimeXa, respectively. Lower visitation rates of bed bugs were recorded for areas treated with MotherEarth D, Alpine and CimeXa than that of DeltaDust, Tempo 1% Dust, and Tri-Die Silica + Pyrethrum Dust. Bed bugs spent less time in areas treated with Tri-Die Dust, CimeXa, Alpine, and MotherEarth D than DeltaDust and Tempo 1% Dust, and they exhibited a reduction in locomotor parameters when crawling on areas treated with CimeXa and Alpine. The implications of these responses to bed bug control are discussed. PMID:28786920

Effective Dust Control Systems on Concrete Dowel Drilling Machinery

PubMed Central

Echt, Alan S.; Sanderson, Wayne T.; Mead, Kenneth R.; Feng, H. Amy; Farwick, Daniel R.; Farwick, Dawn Ramsey

2016-01-01

Rotary-type percussion dowel drilling machines, which drill horizontal holes in concrete pavement, have been documented to produce respirable crystalline silica concentrations above recommended exposure criteria. This places operators at potential risk for developing health effects from exposure. United States manufacturers of these machines offer optional dust control systems. The effectiveness of the dust control systems to reduce respirable dust concentrations on two types of drilling machines was evaluated under controlled conditions with the machines operating inside large tent structures in an effort to eliminate secondary exposure sources not related to the dowel-drilling operation. Area air samples were collected at breathing zone height at three locations around each machine. Through equal numbers of sampling rounds with the control systems randomly selected to be on or off, the control systems were found to significantly reduce respirable dust concentrations from a geometric mean of 54 mg per cubic meter to 3.0 mg per cubic meter on one machine and 57 mg per cubic meter to 5.3 mg per cubic meter on the other machine. This research shows that the dust control systems can dramatically reduce respirable dust concentrations by over 90% under controlled conditions. However, these systems need to be evaluated under actual work conditions to determine their effectiveness in reducing worker exposures to crystalline silica below hazardous levels. PMID:27074062

"Dust Devils": Gardening Agents on the Surface of Mars, and Hidden Hazards to Human Exploration?

NASA Technical Reports Server (NTRS)

Marshall, J.; Smith, P.; White, B.; Farrell, W.

1999-01-01

Dust devils are familiar sites in the and regions of the world: they can produce quite spectacular displays of dust lofting when the vortices scavenge very loose dust from a dry lake bed or from recently disturbed agricultural fields. If one were to arrive at the center of an arid region, take one photograph, or even a series of photographs over a period of several days, then return the images for laboratory analysis, it would be most likely concluded that the region was inactive from an aeolian perspective. No images of general dust movement were obtained, nor were any dust devils "caught on camera" owing to their ephemeral and unpredictable appearance, and the fact that there was deceptively little residue of their actions. If, however, a camera were to take a 360 degree continuous recording over a period of a year, and the film were then to be shown at high speed over a period a several minutes, the impression might be that of a region ravaged by air vorticity and dust movement. Extrapolate this over geological time, and it is possible to visualize dust devils as prime aeolian agents, rather than insignificant vagaries of nature, On Mars, the thin atmosphere permits the surface of the planet to be heated but it does not itself retain heat with the capacity of the earth's atmosphere. This gives rise to greater thermal instability near the surface of Mars as "warm" air pockets diapiritically inject themselves into higher atmospheric layers. Resulting boundary-layer vorticity on Mars might therefore be expected to produce dust devils in abundance, if only seasonally. The spectacular images of dust devils obtained by Pathfinder within its brief functional period on the planet testify to the probability of highly frequent surface vorticity in light of the above reasoning about observational probability. Notably, the Pathfinder devils appeared to be at least a kilometer in height. There are several consequences for the geology of Mars, and for human exploration, if dust devils are to be expected in reasonable abundance. First, from a geological perspective, the vortices will act as "gardening" agents for the top few centimeters of entrainable material. Over time (hundreds of millions, or billions of years being available), they will cover the surface with scouring paths, and the grain sizes that can be lofted by a vortex probably extends over the whole sand to dust range. The depositional paths are, of course, much larger, so that vortex-induced deposition is more widespread than vortex-induced erosion, and will without doubt, affect the whole region in which the dust devils occur (this might explain why rocks at the Viking site seemed oddly capped with dust in a region apparently subject to general aeolian scouring). On Mars, the lift forces in dust devils might be less than on earth owing to the much thinner atmosphere, but this may be counterbalanced by lower gravity and greater vortex velocities. Certainly, when active, other aeolian phenomena on Mars --sand motion and dust storms, seem no less energetic and no less capable of lofting sediments than equivalent terrestrial aeolian phenomena. Every several years, within the current climatic regime, the surface of Mars is subject to light dust fall from global dust storms. Over time, this should develop a very uniform surface layer, with commensurate uniformity in grain size, mineralogy, albedo, color, and general spectroscopic properties. Dust devils will disturb this situation by continually mixing the surface dust with underlying layers, perhaps composed of silt and sand. This size mixing will also involve compositional mixing. After some years, the thin layer of dust that may be difficult to entrain alone, becomes progressively mixed with coarser materials that could reduce the general aeolian threshold of the soil. Certainly the continual disturbance by vorticity will prevent surface stabilization that may bind or indurate grains (caused by slow cementation or ice welding at grain boundaries). If dust devils continually loft dust to kilometer heights, and the dust is sprayed into many cubic kilometers of atmosphere each time, could the devils produce a continual background of atmospheric dust that might be mistaken for the fallout of a distant large-scale dust storm? From a human exploration perspective, dust devils are unlikely to pose any, life- threatening situation for an astronaut unfortunate enough to encounter a momentary swirling cloud of loose soil. However, it is noted that pervasive dust is probably one of the greatest long-term hazards for a human encampment. The fineness and penetration capabilities of the dust, its electrostatic adhesive properties, and its complete ubiquity, render the material a persistent nuisance at best, but at worst, over a period of many months it is possible that space suits, machinery, habitat interiors, air filters, and so forth, could become jeopardized. Owing to dust penetration, the space suits used in the Apollo landings were rendered unusable after a few EVA activities. There will be a definite attempt to situate a human colony on Mars in an area that is far removed from the regions of the planet known for being the centers of major dust storms. At the heart of these storm systems, the dust lofting mechanics are unknown, but they are energetic and perhaps potentially life-threatening for an astronaut. Locating a colony in a region that appears from space to be meteorologically benign may lead to colony placement in a region prone to dust devils, but dust devils are not (or have not been) detectable from orbital observations: the region surveyed for placement will appear like the apparently inactive and area referred to earlier. The region may be spared from highly energetic weather systems, but it may not be necessarily immune from continual dust disturbance. Additional information is contained in the original.

"Dust Devils": Gardening Agents on the Surface of Mars, and Hidden Hazards to Human Exploration?

NASA Astrophysics Data System (ADS)

Marshall, J.; Smith, P.; White, B.; Farrell, W.

1999-09-01

Dust devils are familiar sites in the and regions of the world: they can produce quite spectacular displays of dust lofting when the vortices scavenge very loose dust from a dry lake bed or from recently disturbed agricultural fields. If one were to arrive at the center of an arid region, take one photograph, or even a series of photographs over a period of several days, then return the images for laboratory analysis, it would be most likely concluded that the region was inactive from an aeolian perspective. No images of general dust movement were obtained, nor were any dust devils "caught on camera" owing to their ephemeral and unpredictable appearance, and the fact that there was deceptively little residue of their actions. If, however, a camera were to take a 360 degree continuous recording over a period of a year, and the film were then to be shown at high speed over a period a several minutes, the impression might be that of a region ravaged by air vorticity and dust movement. Extrapolate this over geological time, and it is possible to visualize dust devils as prime aeolian agents, rather than insignificant vagaries of nature, On Mars, the thin atmosphere permits the surface of the planet to be heated but it does not itself retain heat with the capacity of the earth's atmosphere. This gives rise to greater thermal instability near the surface of Mars as "warm" air pockets diapiritically inject themselves into higher atmospheric layers. Resulting boundary-layer vorticity on Mars might therefore be expected to produce dust devils in abundance, if only seasonally. The spectacular images of dust devils obtained by Pathfinder within its brief functional period on the planet testify to the probability of highly frequent surface vorticity in light of the above reasoning about observational probability. Notably, the Pathfinder devils appeared to be at least a kilometer in height. There are several consequences for the geology of Mars, and for human exploration, if dust devils are to be expected in reasonable abundance. First, from a geological perspective, the vortices will act as "gardening" agents for the top few centimeters of entrainable material. Over time (hundreds of millions, or billions of years being available), they will cover the surface with scouring paths, and the grain sizes that can be lofted by a vortex probably extends over the whole sand to dust range. The depositional paths are, of course, much larger, so that vortex-induced deposition is more widespread than vortex-induced erosion, and will without doubt, affect the whole region in which the dust devils occur (this might explain why rocks at the Viking site seemed oddly capped with dust in a region apparently subject to general aeolian scouring). On Mars, the lift forces in dust devils might be less than on earth owing to the much thinner atmosphere, but this may be counterbalanced by lower gravity and greater vortex velocities. Certainly, when active, other aeolian phenomena on Mars --sand motion and dust storms, seem no less energetic and no less capable of lofting sediments than equivalent terrestrial aeolian phenomena. Every several years, within the current climatic regime, the surface of Mars is subject to light dust fall from global dust storms. Over time, this should develop a very uniform surface layer, with commensurate uniformity in grain size, mineralogy, albedo, color, and general spectroscopic properties. Dust devils will disturb this situation by continually mixing the surface dust with underlying layers, perhaps composed of silt and sand. This size mixing will also involve compositional mixing. After some years, the thin layer of dust that may be difficult to entrain alone, becomes progressively mixed with coarser materials that could reduce the general aeolian threshold of the soil. Certainly the continual disturbance by vorticity will prevent surface stabilization that may bind or indurate grains (caused by slow cementation or ice welding at grain boundaries). If dust devils continually loft dust to kilometer heights, and the dust is sprayed into many cubic kilometers of atmosphere each time, could the devils produce a continual background of atmospheric dust that might be mistaken for the fallout of a distant large-scale dust storm? From a human exploration perspective, dust devils are unlikely to pose any, life- threatening situation for an astronaut unfortunate enough to encounter a momentary swirling cloud of loose soil. However, it is noted that pervasive dust is probably one of the greatest long-term hazards for a human encampment. The fineness and penetration capabilities of the dust, its electrostatic adhesive properties, and its complete ubiquity, render the material a persistent nuisance at best, but at worst, over a period of many months it is possible that space suits, machinery, habitat interiors, air filters, and so forth, could become jeopardized. Owing to dust penetration, the space suits used in the Apollo landings were rendered unusable after a few EVA activities. There will be a definite attempt to situate a human colony on Mars in an area that is far removed from the regions of the planet known for being the centers of major dust storms. At the heart of these storm systems, the dust lofting mechanics are unknown, but they are energetic and perhaps potentially life-threatening for an astronaut. Locating a colony in a region that appears from space to be meteorologically benign may lead to colony placement in a region prone to dust devils, but dust devils are not (or have not been) detectable from orbital observations: the region surveyed for placement will appear like the apparently inactive and area referred to earlier. The region may be spared from highly energetic weather systems, but it may not be necessarily immune from continual dust disturbance. Additional information is contained in the original.

Paleodust variability since the Last Glacial Maximum and implications for iron inputs to the ocean

NASA Astrophysics Data System (ADS)

Albani, S.; Mahowald, N. M.; Murphy, L. N.; Raiswell, R.; Moore, J. K.; Anderson, R. F.; McGee, D.; Bradtmiller, L. I.; Delmonte, B.; Hesse, P. P.; Mayewski, P. A.

2016-04-01

Changing climate conditions affect dust emissions and the global dust cycle, which in turn affects climate and biogeochemistry. In this study we use observationally constrained model reconstructions of the global dust cycle since the Last Glacial Maximum, combined with different simplified assumptions of atmospheric and sea ice processing of dust-borne iron, to provide estimates of soluble iron deposition to the oceans. For different climate conditions, we discuss uncertainties in model-based estimates of atmospheric processing and dust deposition to key oceanic regions, highlighting the large degree of uncertainty of this important variable for ocean biogeochemistry and the global carbon cycle. We also show the role of sea ice acting as a time buffer and processing agent, which results in a delayed and pulse-like soluble iron release into the ocean during the melting season, with monthly peaks up to ~17 Gg/month released into the Southern Oceans during the Last Glacial Maximum (LGM).

Occupational exposures associated with severe exacerbation of asthma.

PubMed

Henneberger, P K; Liang, X; Lillienberg, L; Dahlman-Höglund, A; Torén, K; Andersson, E

2015-02-01

The exacerbation of asthma by workplace conditions is common, but little is known about which agents pose a risk. We used data from an existing survey of adults with asthma to identify occupational exposures associated with severe exacerbation of asthma. Questionnaires were completed by 557 working adults with asthma. Severe exacerbation of asthma in the past 12 months was defined as asthma-related hospitalization, or reports of both unplanned asthma care and treatment with a short course of oral corticosteroids. Occupational exposures for the same time period were assessed using an asthma-specific job exposure matrix. We modeled severe exacerbation to yield prevalence ratios (PRs) for exposures while controlling for potential confounders. A total of 164 participants (29%) were positive for severe exacerbation, and 227 (40.8%) were assessed as being exposed to asthma agents at work. Elevated PRs were observed for several specific agents, notably the irritant subcategories of environmental tobacco smoke (PR 1.84, 95%CI 1.34-2.51) among all participants, inorganic dusts (PR 2.53, 95%CI 1.37-4.67) among men, and the low molecular weight subcategory of other highly reactive agents (PR 1.97, 95%CI 1.08-3.60) among women. Among working adults with asthma, severe exacerbation was associated with several occupational agents.

House-Dust Allergy

PubMed Central

Johnson, C. A.

1982-01-01

House-dust allergy is a common cause of perennial allergic rhinitis and extrinsic asthma. Symptoms tend to be worse when the patient is in bed. A positive skin test properly performed and interpreted confirms the diagnosis. The house-dust mite is the most important antigenic component of house-dust. Treatment consists of environmental control directed at reducing the mite content of bedroom dust, plus control of symptoms with drugs. Immunotherapy is controversial. ImagesFig. 1 PMID:21286201

Iceland as the largest source of natural air pollution in the Arctic

NASA Astrophysics Data System (ADS)

Dagsson Waldhauserova, Pavla; Meinander, Outi; Olafsson, Haraldur; Arnalds, Olafur

2017-04-01

Arctic aerosols are often attributed to the Arctic Haze and long-range transport tracers. There is, however, an important dust source in the Arctic/Sub-arctic region which should receive more attention. The largest desert in the Arctic as well as in the Europe is Iceland with > 40,000 km2 of desert areas. The mean dust suspension frequency was 135 dust days annually in 1949-2012 with decreasing numbers in 2013-2015. The annual dust deposition was calculated as 31-40 million tons yr-1 affecting the area of > 500,000 km2. Satelite MODIS pictures have revealed dust plumes traveling > 1000 km at times. The physical properties of Icelandic dust showed differences in mineralogy, geochemical compositions, shapes, sizes, and colour, compared to the crustal mineral dust. Icelandic dust is of volcanic origin, dark in colour with sharp-tipped shards and large bubbles. About 80% of the particulate matter is volcanic glass rich in heavy metals, such as iron and titanium. Suspended dust measured at the glacial dust source consisted of such high number of close-to-ultrafine particles as concentrations during active eruptions. Generally, about 50% of the suspended PM10 are submicron particles in Iceland. Contrarily, suspended grains > 2 mm were captured during severe dust storm after the 2010 Eyjafjallajokull eruption when the aeolian transport exceeded 11 t m-1 of materials and placed this storms among the most extreme wind erosion events recorded on Earth. Our reflectance measurements showed that Icelandic dust deposited on snow lowers the snow albedo and reduces the snow density as much as Black Carbon. Icelandic volcanic dust tends to act as a positive climate forcing agent, both directly and indirectly, which is different to what generally concluded for crustal dust in the 2013 IPCC report. The high frequency, severity and year-round activity of volcanic dust emissions suggest that Icelandic dust may contribute to Arctic warming.

A randomized trial of the effect of dust control on children's blood lead levels.

PubMed

Lanphear, B P; Winter, N L; Apetz, L; Eberly, S; Weitzman, M

1996-07-01

Dust control is recommended as one of the cornerstones of controlling childhood lead exposure; however, the effectiveness of dust control has not been demonstrated for children who have low to mild elevations in blood lead (ie, less than 25 micrograms/dL). The objective of this study was to determine whether dust control, as performed by families, had an effect on children's blood lead levels and dust lead levels in children's homes. Randomized, controlled trial. Community-based trial in Rochester, NY. One hundred four children, 12 to 31 months of age at baseline. Families and children were randomized to one of two groups. Families of children in the intervention group received cleaning supplies, information about cleaning areas that are often contaminated with lead, and a cleaning demonstration. Families in the control group received only a brochure about lead poisoning prevention. Baseline measurements of lead in blood, house dust, soil, water, and paint were taken from both groups. Seven months after enrollment, a second blood lead assay was obtained, and lead levels in household dust were measured. The main outcome measures were change in blood lead levels and dust lead levels by treatment group. The median blood lead level of children enrolled in the study was 6.7 micrograms/dL (range, 1.7 to 30.6 micrograms/dL). There was no significant difference in the change of children's blood lead levels or dust lead levels by treatment group. The median change in blood lead levels among children in the intervention group was -0.05 micrograms/dL compared with -0.60 micrograms/dL among those in the control group. There also was no significant difference in the change of dust lead by group assignment, although there was a trend toward a significant difference in the percentage of change in dust lead levels on noncarpeted floors, which was greater among houses in the intervention group. These data suggest that an intervention that consists only of providing cleaning supplies and a brief description of dust control is not effective at reducing blood lead levels among urban children with low to mild elevations in blood lead levels at a 7-month follow-up.

An analysis of employee exposure to organic dust at large-scale composting facilities

NASA Astrophysics Data System (ADS)

Sykes, P.; Allen, J. A.; Wildsmith, J. D.; Jones, K. P.

2009-02-01

The occupational health implications from exposure to dust, endotoxin and 1-3 β Glucan at commercial composting sites are uncertain. This study aims to establish employee exposure levels to inhalable and respirable dust, endotoxin and 1-3 β Glucan during various operational practices in the composting process. Personal samples were collected and the inhalable and respirable dust fractions were determined by gravimetric analysis. Endotoxin concentrations were determined using a Limulus Amebocyte Lysate assay (LAL). 1-3 β Glucan levels were estimated using a specific blocking agent to establish the contribution that these compounds gave to the original endotoxin assay. Employees' exposure to dust was found to be generally lower than the levels stipulated in the Control of Substances Hazardous to Health Regulations (COSHH) 2002 (as amended), (median inhalable fraction 1.08 mg/m3, min 0.25 mg/m3 max 10.80 mg/m3, median respirable fraction 0.05 mg/m3, min 0.02 mg/m3, max 1.49 mg/m3). Determination of the biological component of the dust showed that employees' exposures to endotoxin were elevated (median 31.5 EU/m3, min 2.00 EU/m3, max 1741.78 EU/m3), particularly when waste was agitated (median 175.0 EU/m3, min 2.03 EU/m3, max 1741.78 EU/m3). Eight out of 32 (25%) of the personal exposure data for endotoxin exceeded the 200 EU/m3 temporary legal limit adopted in the Netherlands and thirteen out of 32 (40.6%) exceeded the suggested 50 EU/m3 guidance level suggested to protect workers from respiratory health effects. A significant correlation was observed between employee inhalable dust exposure and personal endotoxin concentration (r = 0.728, p<0.05) and also personal endotoxin exposure and 1-3 β Glucan concentration (r = 0.817, p<0.05). Further work is needed to explore the possibility of using inhalable dust concentration as a predictor for personal endotoxin exposure. The general dust levels stipulated in the COSHH Regulations 2002 (as amended) are inadequate for managing the potential health risks associated with endotoxin exposure at composting sites. Employee exposure levels and dose-response disease mechanisms are not well understood at this present time. Consequently, in light of this uncertainty, it is recommended that a precautionary approach be adopted in managing the potential health risks associated with inhalation of organic dusts at composting sites.

Open-air sprays for capturing and controlling airborne float coal dust on longwall faces

PubMed Central

Beck, T.W.; Seaman, C.E.; Shahan, M.R.; Mischler, S.E.

2018-01-01

Float dust deposits in coal mine return airways pose a risk in the event of a methane ignition. Controlling airborne dust prior to deposition in the return would make current rock dusting practices more effective and reduce the risk of coal-dust-fueled explosions. The goal of this U.S. National Institute for Occupational Safety and Health study is to determine the potential of open-air water sprays to reduce concentrations of airborne float coal dust, smaller than 75 µm in diameter, in longwall face airstreams. This study evaluated unconfined water sprays in a featureless tunnel ventilated at a typical longwall face velocity of 3.6 m/s (700 fpm). Experiments were conducted for two nozzle orientations and two water pressures for hollow cone, full cone, flat fan, air atomizing and hydraulic atomizing spray nozzles. Gravimetric samples show that airborne float dust removal efficiencies averaged 19.6 percent for all sprays under all conditions. The results indicate that the preferred spray nozzle should be operated at high fluid pressures to produce smaller droplets and move more air. These findings agree with past respirable dust control research, providing guidance on spray selection and spray array design in ongoing efforts to control airborne float dust over the entire longwall ventilated opening. PMID:29348700

Open-air sprays for capturing and controlling airborne float coal dust on longwall faces.

PubMed

Beck, T W; Seaman, C E; Shahan, M R; Mischler, S E

2018-01-01

Float dust deposits in coal mine return airways pose a risk in the event of a methane ignition. Controlling airborne dust prior to deposition in the return would make current rock dusting practices more effective and reduce the risk of coal-dust-fueled explosions. The goal of this U.S. National Institute for Occupational Safety and Health study is to determine the potential of open-air water sprays to reduce concentrations of airborne float coal dust, smaller than 75 µm in diameter, in longwall face airstreams. This study evaluated unconfined water sprays in a featureless tunnel ventilated at a typical longwall face velocity of 3.6 m/s (700 fpm). Experiments were conducted for two nozzle orientations and two water pressures for hollow cone, full cone, flat fan, air atomizing and hydraulic atomizing spray nozzles. Gravimetric samples show that airborne float dust removal efficiencies averaged 19.6 percent for all sprays under all conditions. The results indicate that the preferred spray nozzle should be operated at high fluid pressures to produce smaller droplets and move more air. These findings agree with past respirable dust control research, providing guidance on spray selection and spray array design in ongoing efforts to control airborne float dust over the entire longwall ventilated opening.

Effective dust control systems on concrete dowel drilling machinery.

PubMed

Echt, Alan S; Sanderson, Wayne T; Mead, Kenneth R; Feng, H Amy; Farwick, Daniel R; Farwick, Dawn Ramsey

2016-09-01

Rotary-type percussion dowel drilling machines, which drill horizontal holes in concrete pavement, have been documented to produce respirable crystalline silica concentrations above recommended exposure criteria. This places operators at potential risk for developing health effects from exposure. United States manufacturers of these machines offer optional dust control systems. The effectiveness of the dust control systems to reduce respirable dust concentrations on two types of drilling machines was evaluated under controlled conditions with the machines operating inside large tent structures in an effort to eliminate secondary exposure sources not related to the dowel-drilling operation. Area air samples were collected at breathing zone height at three locations around each machine. Through equal numbers of sampling rounds with the control systems randomly selected to be on or off, the control systems were found to significantly reduce respirable dust concentrations from a geometric mean of 54 mg per cubic meter to 3.0 mg per cubic meter on one machine and 57 mg per cubic meter to 5.3 mg per cubic meter on the other machine. This research shows that the dust control systems can dramatically reduce respirable dust concentrations by over 90% under controlled conditions. However, these systems need to be evaluated under actual work conditions to determine their effectiveness in reducing worker exposures to crystalline silica below hazardous levels.

[The dispensary observation of patients with chronic nonspecific lung diseases who work in a dust-producing industry with a high radionuclide level as a consequence of the accident at the Chernobyl Atomic Electric Power Station].

PubMed

Mal'tsev, V I; Kolpakov, M Iu; Iakobchuk, A V; Golovko, V A

1992-08-01

Patients working at a small mining institution and suffering of chronic unspecific pulmonary diseases due to high dust and radionuclide contamination levels were examined. Four groups of dispensarization were singled out with the purpose of differential treatment for each group. Such treatment including also antiaggregant agents, nitro-drugs resulted in a good medico-social effect within 2 years.

30 CFR 56.5002 - Exposure monitoring.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Air Quality and Physical Agents Air Quality § 56.5002 Exposure monitoring. Dust, gas, mist, and fume surveys shall be conducted as...

9 CFR 147.24 - Cleaning and disinfecting.

Code of Federal Regulations, 2012 CFR

2012-01-01

... houses: (1) Remove all live “escaped” and dead birds from the building. Blow dust from equipment and...) Use cleaning agents and sanitizers that are registered by the U.S. Environmental Protection Agency as...

9 CFR 147.24 - Cleaning and disinfecting.

Code of Federal Regulations, 2013 CFR

2013-01-01

... houses: (1) Remove all live “escaped” and dead birds from the building. Blow dust from equipment and...) Use cleaning agents and sanitizers that are registered by the U.S. Environmental Protection Agency as...

9 CFR 147.24 - Cleaning and disinfecting.

Code of Federal Regulations, 2014 CFR

2014-01-01

... houses: (1) Remove all live “escaped” and dead birds from the building. Blow dust from equipment and...) Use cleaning agents and sanitizers that are registered by the U.S. Environmental Protection Agency as...

9 CFR 147.24 - Cleaning and disinfecting.

Code of Federal Regulations, 2011 CFR

2011-01-01

... houses: (1) Remove all live “escaped” and dead birds from the building. Blow dust from equipment and...) Use cleaning agents and sanitizers that are registered by the U.S. Environmental Protection Agency as...

Coupling the Mars Dust and Water Cycles: Investigating the Role of Clouds in Controlling the Vertical Distribution of Dust During N. H. Summer

NASA Technical Reports Server (NTRS)

Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Wilson, R. J.

2014-01-01

The dust cycle is critically important for the current climate of Mars. The radiative effects of dust impact the thermal and dynamical state of the atmosphere (Gierasch and Goody, 1968; Haberle et al., 1982; Zurek et al., 1992). Although dust is present in the Martian atmosphere throughout the year, the level of dustiness varies with season. The atmosphere is generally the dustiest during northern fall and winter and the least dusty during northern spring and summer (Smith, 2004). Dust particles are lifted into the atmosphere by dust storms that range in size from meters to thousands of kilometers across (Cantor et al., 2001). During some years, regional storms combine to produce hemispheric or planet encircling dust clouds that obscure the surface and raise atmospheric temperatures by as much as 40 K (Smith et al., 2002). Key recent observations of the vertical distribution of dust indicate that elevated layers of dust exist in the tropics and sub-tropics throughout much of the year (Heavens et al., 2011). These observations have brought particular focus on the processes that control the vertical distribution of dust in the Martian atmosphere. The goal of this work is to further our understanding of how clouds in particular control the vertical distribution of dust, particularly during N. H. spring and summer

30 CFR 71.301 - Respirable dust control plan; approval by District Manager and posting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... District Manager and posting. 71.301 Section 71.301 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... plan; approval by District Manager and posting. (a) The District Manager will approve respirable dust control plans on a mine-by-mine basis. When approving respirable dust control plans, the District Manager...

Common Occupational Disorders: Asthma, COPD, Dermatitis, and Musculoskeletal Disorders.

PubMed

Bepko, Jennifer; Mansalis, Katherine

2016-06-15

An occupational illness is an event or exposure that occurs in the workplace that causes or contributes to a condition or worsens a preexisting condition. If an occupational disorder is suspected, a directed history should be taken with particular attention to establishing a temporal relationship of symptoms and exposure at work. Occupational asthma is the most prevalent occupational lung disorder in industrialized countries and presents with classic asthma symptoms (cough, difficulty breathing, chest tightness, wheezing). Occupational chronic obstructive pulmonary disease has been linked with exposure to nonspecific vapors, gases, dusts, fumes, and cigarette smoke. Occupational contact dermatitis is the most common dermal exposure. It can be caused by exposure to a variety of agents, including primary irritants or sensitizers, physical agents, mechanical trauma, and biologic agents. Occupational musculoskeletal disorders include many common repetitive injuries such as carpal tunnel syndrome and medial or lateral epicondylitis. Treatment of occupational disorders is generally the same as for nonoccupational disorders. Ideally, the exposure should be controlled to protect the worker. The impact of an occupational injury reaches beyond lost wages and can have a negative impact on quality of life.

Bacterial and fungal components in house dust of farm children, Rudolf Steiner school children and reference children--the PARSIFAL Study.

PubMed

Schram, D; Doekes, G; Boeve, M; Douwes, J; Riedler, J; Ublagger, E; von Mutius, E; Budde, J; Pershagen, G; Nyberg, F; Alm, J; Braun-Fahrländer, C; Waser, M; Brunekreef, B

2005-05-01

Growing up on a farm and an anthroposophic lifestyle are associated with a lower prevalence of allergic diseases in childhood. It has been suggested that the enhanced exposure to endotoxin is an important protective factor of farm environments. Little is known about exposure to other microbial components on farms and exposure in anthroposophic families. To assess the levels and determinants of bacterial endotoxin, mould beta(1,3)-glucans and fungal extracellular polysaccharides (EPS) in house dust of farm children, Steiner school children and reference children. Mattress and living room dust was collected in the homes of 229 farm children, 122 Steiner children and 60 and 67 of their respective reference children in five European countries. Stable dust was collected as well. All samples were analysed in one central laboratory. Determinants were assessed by questionnaire. Levels of endotoxin, EPS and glucans per gram of house dust in farm homes were 1.2- to 3.2-fold higher than levels in reference homes. For Steiner children, 1.1- to 1.6-fold higher levels were observed compared with their reference children. These differences were consistently found across countries, although mean levels varied considerably. Differences between groups and between countries were also significant after adjustment for home and family characteristics. Farm children are not only consistently exposed to higher levels of endotoxin, but also to higher levels of mould components. Steiner school children may also be exposed to higher levels of microbial agents, but differences with reference children are much less pronounced than for farm children. Further analyses are, however, required to assess the association between exposure to these various microbial agents and allergic and airway diseases in the PARSIFAL population.

Contaminants in human nail dust: an occupational hazard in podiatry?

PubMed Central

2014-01-01

Background There has been limited literature indicating that podiatrists’ health may be at risk from exposure to human nail dust. Previous studies carried out in the UK have shown that large amounts of dust become airborne during the human nail drilling procedure and are present in the air up to 10 hours after a clinical session. This increases the risk of Respiratory Tract (RT) infection for the practitioner. Methods This study used a nasal swabbing technique and fungal culture to determine whether podiatrists (n = 50) had the same microbes present in their nasal cavities as non-podiatry health professional control group (n = 45). All swabs were cultured, counted and identified for each subject. Survey data of use and type of nail drill, type of mask used and frequency of change over a two week period. Results The results showed podiatrists had a greater range of microbes in their nasal cavities although the controls had greater overall numbers of organisms. The known pathogen and common mould, Aspergillus fumigatus was ost commonly found fungus within the podiatric group with 44% of the group having the fungus present. All nail drills used by the podiatrists had some form of dust extraction (except one). Of concern was 17% (n = 8) of the podiatrists did not use a mask at all whilst drilling and seemed unaware of any infection control issues. Simple disposable masks were the most frequently worn with only half being changed after each patient further increasing the cross infection risk Conclusion The high levels of Aspergilus contamination is a significant finding in the podiatry group as this fungus is small enough to enter the tissue of the nasal cavity and as a small particle will stay airborne in the room for up to 16 hours. Aspergilus has been shown to cause brain and soft tissue tumours in extreme cases. The high levels of upper respiratory track problems reported in the literature may well be caused by this fungal agent. The non use and use of inappropriate masks by podiatrists is clearly an occupational hazard to their health and well being. PMID:24552311

Contaminants in human nail dust: an occupational hazard in podiatry?

PubMed

Tinley, Paul D; Eddy, Karen; Collier, Peter

2014-02-20

There has been limited literature indicating that podiatrists' health may be at risk from exposure to human nail dust. Previous studies carried out in the UK have shown that large amounts of dust become airborne during the human nail drilling procedure and are present in the air up to 10 hours after a clinical session. This increases the risk of Respiratory Tract (RT) infection for the practitioner. This study used a nasal swabbing technique and fungal culture to determine whether podiatrists (n = 50) had the same microbes present in their nasal cavities as non-podiatry health professional control group (n = 45). All swabs were cultured, counted and identified for each subject. Survey data of use and type of nail drill, type of mask used and frequency of change over a two week period. The results showed podiatrists had a greater range of microbes in their nasal cavities although the controls had greater overall numbers of organisms. The known pathogen and common mould, Aspergillus fumigatus was ost commonly found fungus within the podiatric group with 44% of the group having the fungus present. All nail drills used by the podiatrists had some form of dust extraction (except one). Of concern was 17% (n = 8) of the podiatrists did not use a mask at all whilst drilling and seemed unaware of any infection control issues. Simple disposable masks were the most frequently worn with only half being changed after each patient further increasing the cross infection risk The high levels of Aspergilus contamination is a significant finding in the podiatry group as this fungus is small enough to enter the tissue of the nasal cavity and as a small particle will stay airborne in the room for up to 16 hours. Aspergilus has been shown to cause brain and soft tissue tumours in extreme cases. The high levels of upper respiratory track problems reported in the literature may well be caused by this fungal agent. The non use and use of inappropriate masks by podiatrists is clearly an occupational hazard to their health and well being.

[The specific bronchial provocation test in the diagnosis of occupational asthma].

PubMed

Fraj, J; Duce, F; Lezaun, A; Colás, C; Domínguez, M A; Abadía, M C

1997-10-01

Specific bronchial challenge (SBC) testing is a key technique for diagnosing the origin of occupational asthma (OA). SBC is indicated in specific circumstances, including whenever several agents present in the work environment may be the cause of OA, when new or unusual occupational agents need to be identified, when evidence for legal action is required, or when research is conducted. SBC procedures are not standardized, because of the great diversity of occupational agents and the variety of physical and chemical properties involved. Thus, SBC testing with agents found in fumes, gases or vapors can be administered in special cabins or in closed circuits with continuous monitoring of sub-irritant concentrations. Agents found in dust, most but not all of which have high molecular weights, may be appropriate for routine SBC testing in an allergy laboratory. This paper will treat only these cases. SBC must be formed in specialized centers by experienced personnel, as it is a sophisticated and potentially dangerous technique. We describe a series of 20 patients diagnosed of OA in our unit over the past two years in whom SBC provided an etiologic diagnosis. All were exposed to dust or aerosols at work. The cause was a substance of high molecular weight in 17 cases, and low molecular weight in 3. The procedure used is described and models of bronchial response are discussed.

Laboratory evaluation to reduce respirable crystalline silica dust when cutting concrete roofing tiles using a masonry saw.

PubMed

Carlo, Rebecca V; Sheehy, John; Feng, H Amy; Sieber, William K

2010-04-01

Respirable crystalline silica dust exposure in residential roofers is a recognized hazard resulting from cutting concrete roofing tiles. Roofers cutting tiles using masonry saws can be exposed to high concentrations of respirable dust. Silica exposures remain a serious threat for nearly two million U.S. construction workers. Although it is well established that respiratory diseases associated with exposure to silica dust are preventable, they continue to occur and cause disability or death. The effectiveness of both a commercially available local exhaust ventilation (LEV) system and a water suppression system in reducing silica dust was evaluated separately. The LEV system exhausted 0.24, 0.13, or 0.12 m(3)/sec of dust laden air, while the water suppression system supplied 0.13, 0.06, 0.03, or 0.02 L/sec of water to the saw blade. Using a randomized block design, implemented under laboratory conditions, the aforementioned conditions were evaluated independently on two types of concrete roofing tiles (s-shape and flat) using the same saw and blade. Each engineering control (LEV or water suppression) was replicated eight times, or four times for each type of tile. Analysis of variance was performed by comparing the mean airborne respirable dust concentrations generated during each run and engineering control treatment. The use of water controls and ventilation controls compared with the "no control" treatment resulted in a statistically significant (p < 0.05) reduction of mean respirable dust concentrations generated per tile cut. The percent reduction for respirable dust concentrations was 99% for the water control and 91% for the LEV. Results suggest that water is an effective method for reducing crystalline silica exposures. However, water damage potential, surface discolorations, cleanup, slip hazards, and other requirements may make the use of water problematic in many situations. Concerns with implementing an LEV system to control silica dust exposures include sufficient capture velocity, additional weight of the saw with the LEV system, electricity connections, and cost of air handling unit.

House dust mites, our intimate associates.

PubMed

Nadchatram, M

2005-06-01

House dust mites have lived in human contact from time immemorial. Human dander or dead skin constitutes the major organic component of the house dust ecosystem. Because the mites feed on dander, dust mites and human association will continue to co-exist as part of our environment. Efficient house-keeping practice is the best form of control to reduce infestation. However, special precautions are important when individuals are susceptible or sensitive to dust mites. House dust mites are responsible for causing asthma, rhinitis and contact dermatitis. The respiratory allergies are caused by the inhalation of dead or live mites, their faecal matter or other byproducts. Immune factors are of paramount importance in the development of dust related or mite induced respiratory diseases. House dust mites were found in some 1,000 samples of dust taken from approximately 330 dwellings in Peninsular Malaysia and Singapore. Mattresses, carpets, corners of a bedroom, and floor beneath the bed are favourable dust mite habitats. The incriminating species based on studies here and elsewhere, as well as many other species of dust mites of unknown etiological importance are widely distributed in Malaysian homes. Density of dust mites in Malaysia and Singapore is greater than in temperate countries. Prevention and control measures with reference to subjects sensitive to dust mite allergies, including chemical control described in studies conducted in Europe and America are discussed. However, a cost free and most practical way to remove mites, their faecal matter and other products is to resort to sunning the bedding and carpets to kill the living mites, and then beaten and brushed to remove the dust and other components.

Probing Dust Formation Around Evolved Stars with Near-Infrared Interferometry

NASA Astrophysics Data System (ADS)

Sargent, B.; Srinivasan, S.; Riebel, D.; Meixner, M.

2014-09-01

Near-infrared interferometry holds great promise for advancing our understanding of the formation of dust around evolved stars. For example, the Magdalena Ridge Observatory Interferometer (MROI), which will be an optical/near-infrared interferometer with down to submilliarcsecond resolution, includes studying stellar mass loss as being of interest to its Key Science Mission. With facilities like MROI, many questions relating to the formation of dust around evolved stars may be probed. How close to an evolved star such as an asymptotic giant branch (AGB) or red supergiant (RSG) star does a dust grain form? Over what temperature ranges will such dust form? How does dust formation temperature and distance from star change as a function of the dust composition (carbonaceous versus oxygen-rich)? What are the ranges of evolved star dust shell geometries, and does dust shell geometry for AGB and RSG stars correlate with dust composition, similar to the correlation seen for planetary nebula outflows? At what point does the AGB star become a post-AGB star, when dust formation ends and the dust shell detaches? Currently we are conducting studies of evolved star mass loss in the Large Magellanic Cloud using photometry from the Surveying the Agents of a Galaxy's Evolution (SAGE; PI: M. Meixner) Spitzer Space Telescope Legacy program. We model this mass loss using the radiative transfer program 2Dust to create our Grid of Red supergiant and Asymptotic giant branch ModelS (GRAMS). For simplicity, we assume spherical symmetry, but 2Dust does have the capability to model axisymmetric, non-spherically-symmetric dust shell geometries. 2Dust can also generate images of models at specified wavelengths. We discuss possible connections of our GRAMS modeling using 2Dust of SAGE data of evolved stars in the LMC and also other data on evolved stars in the Milky Way's Galactic Bulge to near-infrared interferometric studies of such stars. By understanding the origins of dust around evolved stars, we may learn more about the later parts of the life of stardust; e.g., its residence in the interstellar medium, its time spent in molecular clouds, and its inclusion into solid bodies in future planetary systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, E.E.

Molten wax shows considerable promise as a fixative and dust control agent in demolition of radioactively contaminated facilities. Sticky molten wax, modified with special surfactants and wetting agents, is capable of not only coating materials but also penetrating into friable or dusty materials and making them incapable of becoming airborne during demolition. Wax also shows significant promise for stabilization of waste residuals that may be contained in buildings undergoing demolition. Some of the building materials that have been tested to date include concrete, wood, sheet-rock, fiber insulation, lime, rock, and paper. Protective clothing, clay, sand, sulfur, and bentonite clay havemore » been tested as surrogates for certain waste materials that may be encountered during building demolition. The paper describes several potential applications of molten wax for dust control in demolition of radioactive contaminated facilities. As a case-study, this paper describes a research test performed for a pipeline closure project being completed by the Idaho Cleanup Project at the Idaho National Laboratory. The project plans to excavate and remove a section of buried Duriron drain piping containing highly radioactive and friable and 'flighty' waste residuals. A full-scale pipeline mockup containing simulated waste was buried in sand to simulate the direct-buried subsurface condition of the subject piping. The pipeline was pre-heated by drawing hot air through the line with a HEPA vacuum blower unit. Molten wax was pumped into the line and allowed to cool. The line was then broken apart in various places to evaluate the permeation performance of the wax. The wax fully permeated all the surrogate materials rendering them non-friable with a consistency similar to modeling clay. Based on the performance during the mockup, it is anticipated that the wax will be highly effective in controlling the spread of radiological contamination during pipe demolition activities. A larger test was completed this year to simulate the work in more realistic conditions. (authors)« less

Evolutionary pulsational mode dynamics in nonthermal turbulent viscous astrofluids

NASA Astrophysics Data System (ADS)

Karmakar, Pralay Kumar; Dutta, Pranamika

2017-11-01

The pulsational mode of gravitational collapse in a partially ionized self-gravitating inhomogeneous viscous nonthermal nonextensive astrofluid in the presence of turbulence pressure is illustratively analyzed. The constitutive thermal species, lighter electrons and ions, are thermostatistically treated with the nonthermal κ-distribution laws. The inertial species, such as identical heavier neutral and charged dust microspheres, are modelled in the turbulent fluid framework. All the possible linear processes responsible for dust-dust collisions are accounted. The Larson logatropic equations of state relating the dust thermal (linear) and turbulence (nonlinear) pressures with dust densities are included. A regular linear normal perturbation analysis (local) over the complex astrocloud ensues in a generalized quartic dispersion relation with unique nature of plasma-dependent multi-parametric coefficients. A numerical standpoint is provided to showcase the basic mode features in a judicious astronomical paradigm. It is shown that both the kinematic viscosity of the dust fluids and nonthermality parameter (kappa, the power-law tail index) of the thermal species act as stabilizing (damping) agent against the gravity; and so forth. The underlying evolutionary microphysics is explored. The significance of redistributing astrofluid material via waveinduced accretion in dynamic nonhomologic structureless cloud collapse leading to hierarchical astrostructure formation is actualized.

Effects of dust on forest tree health in Zagros oak forests.

PubMed

Moradi, A; Taheri Abkenar, K; Afshar Mohammadian, M; Shabanian, N

2017-10-10

Dust is one of the most devastating factors for the environment threatening all animal and plant species. In many regions, the ecological and economic impact of microdust on scarce species is critical. In the western region of Iran, the Zagros forests have been exposed to dust storms for many years. In this study, the effect of dust on oak trees, the most important trees of Zagros forests, is investigated. For this purpose, 3-year-old seedlings of three species of oak trees under natural conditions were exposed to dust during spring and summer months. Seedlings were divided into two groups; one group was assigned as dust treatment and the other as control that the control group washed regularly to remove dust. Anatomical characteristics of leaves and dust deposits on leaves during the study period were examined by scanning electron microscope (SEM). The rate of photosynthesis and gas exchange in control and treated plants was examined by IRGA, LCI. SEM images showed that stomata structure, trichome density, and epicuticular waxes of leaves are different in all three species. This difference in micromorphology of species influences the effects of dust deposited on the leaves. A comparison of leaf species images in control and dust treatment showed that in dust treatment the percentage of stomata blocked by dust in three species (per unit area) of Quercus infectoria, Q. libni, and Q. brantii were 61/6, 48/4, and 38/1%, respectively. The results of leaf gas exchange investigation indicated that stomatal occlusion by dust had a negative impact on the examined parameters of three oak species (P ≤ 0.01). Thus, gas exchange and photosynthetic rates of the treated species were significantly reduced. The results of both parts of the study showed the vulnerability of the three species to dust as Q. infectoria > Q. libni > Q. brantii. Therefore, based on these findings, dust can disrupt the physiological activities of the studied species and the continuation of the exposure to dust will accelerate the process of destruction of these forests.

Effects of dust storm events on weekly clinic visits related to pulmonary tuberculosis disease in Minqin, China

NASA Astrophysics Data System (ADS)

Wang, Yun; Wang, Ruoyu; Ming, Jing; Liu, Guangxiu; Chen, Tuo; Liu, Xinfeng; Liu, Haixia; Zhen, Yunhe; Cheng, Guodong

2016-02-01

Pulmonary tuberculosis (PTB) is a major public health problem in China. Minqin, a Northwest county of China, has a very high number of annual PTB clinic visits and it is also known for its severe dust storms. The epidemic usually begins in February and ends in July, while the dust storms mainly occur throughout spring and early summer, thereby suggesting that there might be a close link between the causative agent of PTB and dust storms. We investigated the general impact of dust storms on PTB over time by analyzing the variation in weekly clinic visits in Minqin during 2005-2012. We used the Mann-Whitney-Pettitt test and a regression model to determine the seasonal periodicity of PTB and dust storms in a time series, as well as assessing the relationships between meteorological variables and weekly PTB clinic visits. After comparing the number of weekly PTB cases in Gansu province with dust storm events, we detected a clear link between the population dynamics of PTB and climate events, i.e., the onset of epidemics and dust storms (defined by an atmospheric index) occurred in almost the same mean week. Thus, particulate matter might be the cause of PTB outbreaks on dust storm days. It is highly likely that the significant decline in annual clinic visits was closely associated with improvements in the local environment, which prevented desertification and decreased the frequency of dust storm events. To the best of our knowledge, this is the first population-based study to provide clear evidence that a PTB epidemic was affected by dust storms in China, which may give insights into the association between this environmental problem and the evolution of epidemic disease.

Influence of Air Humidity and Water Particles on Dust Control Using Ultrasonic Atomization

NASA Astrophysics Data System (ADS)

Okawa, Hirokazu; Nishi, Kentaro; Shindo, Dai; Kawamura, Youhei

2012-07-01

The influence of air humidity and water particles on dust control was examined using ultrasonic atomization at 2.4 MHz, an acrylic box (61 L), and four types of ore dust samples: green tuff (4 µm), green tuff (6 µm), kaolin, and silica. It was clearly demonstrated that ultrasonic atomization was effective in raising humidity rapidly. However, at high relative air humidity, the water particles remained stable in the box without changing to water vapor. Ultrasonic atomization was applied to suppress dust dispersion and 40-95% dust reduction was achieved at 83% relative air humidity. Dust dispersion was more effective with ultrasonic atomization than without.

Influence of continuous mining arrangements on respirable dust exposures

PubMed Central

Beck, T. W.; Organiscak, J. A.; Pollock, D. E.; Potts, J. D.; Reed, W. R.

2017-01-01

In underground continuous mining operations, ventilation, water sprays and machine-mounted flooded-bed scrubbers are the primary means of controlling respirable dust exposures at the working face. Changes in mining arrangements — such as face ventilation configuration, orientation of crosscuts mined in relation to the section ventilation and equipment operator positioning — can have impacts on the ability of dust controls to reduce occupational respirable dust exposures. This study reports and analyzes dust concentrations measured by the Pittsburgh Mining Research Division for remote-controlled continuous mining machine operators as well as haulage operators at 10 U.S. underground mines. The results of these respirable dust surveys show that continuous miner exposures varied little with depth of cut but are significantly higher with exhaust ventilation. Haulage operators experienced elevated concentrations with blowing face ventilation. Elevated dust concentrations were observed for both continuous miner operators and haulage operators when working in crosscuts driven into or counter to the section airflow. Individual cuts are highlighted to demonstrate instances of minimal and excessive dust exposures attributable to particular mining configurations. These findings form the basis for recommendations for lowering face worker respirable dust exposures. PMID:28529441

Evaluations of bit sleeve and twisted-body bit designs for controlling roof bolter dust

PubMed Central

Beck, T.W.

2015-01-01

Drilling into coal mine roof strata to install roof bolts has the potential to release substantial quantities of respirable dust. Due to the proximity of drill holes to the breathing zone of roof bolting personnel, dust escaping the holes and avoiding capture by the dust collection system pose a potential respiratory health risk. Controls are available to complement the typical dry vacuum collection system and minimize harmful exposures during the initial phase of drilling. This paper examines the use of a bit sleeve in combination with a dust-hog-type bit to improve dust extraction during the critical initial phase of drilling. A twisted-body drill bit is also evaluated to determine the quantity of dust liberated in comparison with the dust-hog-type bit. Based on the results of our laboratory tests, the bit sleeve may reduce dust emissions by one-half during the initial phase of drilling before the drill bit is fully enclosed by the drill hole. Because collaring is responsible for the largest dust liberations, overall dust emission can also be substantially reduced. The use of a twisted-body bit has minimal improvement on dust capture compared with the commonly used dust-hog-type bit. PMID:26257435

Environmental Isolation of Cryptococcus gattii VGII from Indoor Dust from Typical Wooden Houses in the Deep Amazonas of the Rio Negro Basin

PubMed Central

Brito-Santos, Fábio; Barbosa, Gláucia Gonçalves; Trilles, Luciana; Nishikawa, Marília Martins; Wanke, Bodo; Meyer, Wieland; Carvalho-Costa, Filipe Anibal; Lazéra, Márcia dos Santos

2015-01-01

Cryptococcosis is a human fungal infection of significant mortality and morbidity, especially in the meningoencephalitis form. Cryptococcosis is distributed worldwide and its agents, C. neoformans and C. gattii, present eight major molecular types—VNI-VNIV and VGI-VGIV respectively. The primary cryptococcosis caused by molecular type VGII (serotype B, MAT alpha) prevails in immunocompetent patients in the North and Northeast of Brazil, revealing an endemic regional pattern to this molecular type. Since 1999, C. gattii VGII has been involved in an ongoing outbreak in Canada, and is expanding to the Northwest of the United States, two temperate regions. Exposure to propagules dispersed in the environment, related to various organic substrates, mainly decomposing wood in and around dwellings, initiates the infection process. The present study investigated the presence of the agents of cryptococcosis in dust from dwellings in the upper Rio Negro, municipality of Santa Isabel do Rio Negro in Amazonas state. Indoor dust was collected from 51 houses, diluted and plated on bird seed agar. Dark brown colonies were identified phenotypically, and genotypically by URA5 restriction fragment length polymorphism analysis and multilocus sequence typing (MLST). The mating type was identified using pheromone-specific primers. Three of the 51 houses were positive for C. gattii molecular type VGII, MATα and MATa, showing a high prevalence of this agent. MLST studies identified eight subtypes, VGIIb (ST7), VGIIa (ST20), (ST5) and 5 new subtypes unique to the region. For the first time in the state of Amazonas, C. gattii VGII MATα and MATa were isolated from the environment and correlates with endemic cryptococcosis in this state. This is the first description of MLST subtypes on environmental isolates in the Brazilian Amazon, indicating domiciliary dust as a potential source for human infection with different subtypes of C. gattii VGII MATα and MATa. PMID:25688971

Interannual Modulation of Subtropical Atlantic Boreal Summer Dust Variability by ENSO

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeFlorio, Mike; Goodwin, Ian D.; Cayan, Dan

2016-01-01

Dust variability in the climate system has been studied for several decades, yet there remains an incomplete understanding of the dynamical mechanisms controlling interannual and decadal variations in dust transport. The sparseness of multi-year observational datasets has limited our understanding of the relationship between climate variations and atmospheric dust. We use available observations and a century-length fully coupled Community Earth System Model (CESM) simulation to show that the El Niño- Southern Oscillation (ENSO) exerts a control on North African dust transport during boreal summer. In CESM, this relationship is stronger over the dusty tropical North Atlantic than near Barbados, onemore » of the few sites having a multi-decadal observed record. During strong La Niña summers in CESM, a statistically significant increase in lower tropospheric easterly wind is associated with an increase in North African dust transport over the Atlantic. Barbados dust and Pacific SST variability are only weakly correlated in both observations and CESM, suggesting that other processes are controlling the crossbasin variability of dust. We also use our CESM simulation to show that the relationship between downstream North African dust transport and ENSO fluctuates on multidecadal timescales and may be modulated by the North Atlantic Oscillation (NAO). Our findings indicate that existing observations of dust over the tropical North Atlantic are not extensive enough to completely describe the variability of dust and dust transport, and demonstrate the importance of global models to supplement and interpret observational records.« less

A Survey and Evaluation of Chemical Warfare Agent-Decontaminants and Decontamination

DTIC Science & Technology

1984-10-15

0.21 citric acid monohydrate, 0.05% detergent, and 98.251 water) all contain calcium hypochlorite and have been used for decontaminating agents from...water repellent chemicals consist of an aluminum salt of a saturated carboxylic acid (such as format, acetate, palmitate, or stearate) mixed with...been conducted. Sawdust, soil, silicone, coal dust, amine or sulfonic acid -containing polymers, organic and inorganic ion-exchange materials, and metal

[Analysis on occupational exposure levels and control effectiveness of dust in cement production line of new dry method].

PubMed

Wang, De-jun; Sui, Shao-feng; Kong, Fan-ling; Huang, Dong-hai

2012-11-01

To investigate the occupational exposure levels of dust in new suspension preheated dry process (NSP) cement production line and put forward rectification measures for dust-exposed posts, and to provide ideas for the modern cement production enterprises in dust control and occupational health management. Occupational health field investigation combined with field test were used to measure the time-weighted average concentration (C(TWA)) of the dust in the workplace. Rectification measures were taken for the dust-exposed posts with unqualified dust concentration, and the protective effects of dustproof facilities in the rectified workplace were evaluated. The field investigation revealed incompletely closed dustproof facilities, improperly set dust hoods, excess of dust leakage points, and other problems in the dust-exposed posts of an NSP cement production line before rectification, and the dustproof facilities could hardly exert dust removal effect. The field test showed that the vast majority of dust-exposed posts had the dust concentrations exceeding the occupational exposure limits (OELs), with a qualified rate as low as 31.8%. A series of rectification measures were taken for these posts. After the rectification, the dust-exposed posts demonstrated dramatically dropped C(TWA), and the qualified rate of dust concentration in the dust-exposed posts rose to 90.9%. The dust hazards in NSP cement production line cannot be ignored. Taking appropriate protective measures are critical for curbing dust hazards in modern cement production.

Wood chips for dust control on surface-mine haul roads

Treesearch

George P., Jr. Williams

1979-01-01

On a coal haul spur road where water sprinkling was the primary method of dust control, the duration of control was increased tenfold by covering the road surface with a layer of wood chips. The chip blanket prevented existing dust-size particles from being kicked up and swept into plumes by passing traffic, insulated the road surface against evaporation and protected...

Association between HLA genes and dust mite sensitivity in a Brazilian population.

PubMed

da Costa Lima Caniatti, Marcela Caleffi; Borelli, Sueli Donizete; Guilherme, Ana Lúcia Falavigna; Tsuneto, Luiza Tamie

2017-02-01

Type I hypersensitivity, also known as IgE-mediated allergy, is a complex, multifactorial condition whose onset and severity are influenced by both genetic and environmental factors. Mite allergens stimulate the production of humoral response (IgE), especially in children, which is closely involved in atopic asthma and rhinitis. This study aimed to investigate the association between HLA class I (-A, -B, and -C), and HLA class II (-DRB1) genes in individuals sensitive to dust mites (Dermatophagoides farinae, Dermatophagoides pteronyssinus, or Blomia tropicalis) and mite-insensitive controls. 396 participants were grouped as mite-sensitive and mite-insensitive according to immediate hypersensitivity as determined by skin-prick tests, and to HLA genotyping by polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO). After chi-square heterogeneity testing no significant differences were observed in HLA-A, B, and C genes, except for the HLA-DRB1 locus, which, showed a negative association for DRB1∗04, between mite-sensitive and mite-insensitive individuals. In high resolution, DRB1∗04:11 allele was significantly different from all other results (P=0.0042, OR=0.26, and 95%CI=0.09-0.70). The analysis stratified by etiologic agent confirmed these associations. Our results suggest a possible association between HLA-DRB1 genes and hypersensitivity to dust mites. Copyright © 2016 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

Effect of Illumination Angle on the Performance of Dusted Thermal Control Surfaces in a Simulated Lunar Environment

NASA Technical Reports Server (NTRS)

Gaier, James R.

2009-01-01

JSC-1A lunar simulant has been applied to AZ93 and AgFEP thermal control surfaces on aluminum substrates in a simulated lunar environment. The temperature of these surfaces was monitored as they were heated with a solar simulator using varying angles of incidence and cooled in a 30 K coldbox. Thermal modeling was used to determine the solar absorptivity (a) and infrared emissivity (e) of the thermal control surfaces in both their clean and dusted states. It was found that even a sub-monolayer of dust can significantly raise the a of either type of surface. A full monolayer can increase the a/e ratio by a factor of 3 to 4 over a clean surface. Little angular dependence of the a of pristine thermal control surfaces for both AZ93 and AgFEP was observed, at least until 30 from the surface. The dusted surfaces showed the most angular dependence of a when the incidence angle was in the range of 25 to 35 . Samples with a full monolayer, like those with no dust, showed little angular dependence in a. The e of the dusted thermal control surfaces was within the spread of clean surfaces, with the exception of high dust coverage, where a small increase was observed at shallow angles.

Imaging-based dust sensors: equipment and methods

NASA Astrophysics Data System (ADS)

Bonifazi, Giuseppe; Greco, Sonia

2004-05-01

Dust detection and control in real time, represent one of the most challenging problem in all those environments where fine and ultrafine airborne particulate solids products are present. The presence of such products can be linked to several factors, often directly related and influenced by the working-production actions performed. Independently from the causes generating dust, airborne contaminants are an occupational problem of increasing interest as they are related to a wide number of diseases. In particular, airborne dusts are well known to be associated with several classical occupational lung diseases, such as the pneumoconiosis, especially at high levels of exposure. Nowadays there is also an increasing interest in other dust related diseases, from the most serious as cancer and asthma, to those related with allergies or irritation and other illnesses, also occurring at lower levels of exposure. Among the different critical factors influencing health risk for airborne dust exposure, mainly four have to be considered, that is: i) nature of the dust resulting from working in terms of presence of specific poisoning material, i.e. free silica, and morphological and morphometrical attributes of particulates constituting airborne dust; ii) size of the particles, iii) duration of exposure time and, finally, iv) airborne dust concentration in the breathing zone where the worker performs his activity. A correct dust detection is not easy, especially if some of the previous mentioned factors, have to be detected and quantified in real time in order to define specific "on-line" control actions aimed to reduce the level of the exposure to dust of the workers, as for example: i) modification of aspirating devices operating condition, change of filtering cleaning sequence, etc. . The more severe are the environmental conditions, in terms of dust presence (in quantity and quality) more difficult is to utilize efficient sampling devices. Detection devices, in fact, tend to become "blind" to dust as dust presence increases, on the other hand severe dust production conditions is exactly the case where control strategies have to be applied to realize safer conditions for the workers. In this paper the possibility to utilize a new logic to perform an "on-line" airborne dust sampling and analysis utilizing imaging is described with particular reference to dusts flowing in a duct after the caption and before their abatement by classical mechanical filtering. The study was particularly addressed to define, design and implement a logic able to extract those parameters affecting airborne dust behavior with respect to its efficient abatement. All dust sampling was performed directly in an industrial plant where tests were carried out in a controlled environment.

Global dust cycle

NASA Astrophysics Data System (ADS)

Ridgwell, Andy

Dust, micron to submicron particles and mostly comprising soil mineral fragments, affects a multitude of climatic and biogeochemical processes during its journey from its sources on land to sinks on land and in the ocean. Suspended in the atmosphere, the presence of dust can alter both shortwave and longwave radiation balances, enhance cloud nucleation, and affect photochemical reaction rates. Deposited to the land surface, dust has beneficial impacts on soil quality but detrimental implications for human health. At the interface of surface ocean and lower atmosphere, dust deposited to seawater supplies plankton with the essential micronutrient iron and hence provides an important control on marine ecosystems. This chapter reviews these various roles of dust in the Earth system; summarizes the factors controlling the production, transport, and deposition of dust; and, because the causes and consequences of dust are interlinked via climate and atmospheric CO2, discusses the potential importance of dusty feedback in past and future climate change.

Extraction of Thermal Performance Values from Samples in the Lunar Dust Adhesion Bell Jar

NASA Technical Reports Server (NTRS)

Gaier, James R.; Siamidis, John; Larkin, Elizabeth M. G.

2008-01-01

A simulation chamber has been developed to test the performance of thermal control surfaces under dusty lunar conditions. The lunar dust adhesion bell jar (LDAB) is a diffusion pumped vacuum chamber (10(exp -8) Torr) built to test material samples less than about 7 cm in diameter. The LDAB has the following lunar dust simulant processing capabilities: heating and cooling while stirring in order to degas and remove adsorbed water; RF air-plasma for activating the dust and for organic contaminant removal; RF H/He-plasma to simulate solar wind; dust sieving system for controlling particle sizes; and a controlled means of introducing the activated dust to the samples under study. The LDAB is also fitted with an in situ Xe arc lamp solar simulator, and a cold box that can reach 30 K. Samples of thermal control surfaces (2.5 cm diameter) are introduced into the chamber for calorimetric evaluation using thermocouple instrumentation. The object of this paper is to present a thermal model of the samples under test conditions and to outline the procedure to extract the absorptance, emittance, and thermal efficiency from the pristine and sub-monolayer dust covered samples.

Extraction of Thermal Performance Values from Samples in the Lunar Dust Adhesion Bell Jar

NASA Technical Reports Server (NTRS)

Gaier, James R.; Siamidis, John; Larkin, Elizabeth M.G.

2008-01-01

A simulation chamber has been developed to test the performance of thermal control surfaces under dusty lunar conditions. The lunar dust adhesion bell jar (LDAB) is a diffusion pumped vacuum chamber (10-8 Torr) built to test material samples less than about 7 cm in diameter. The LDAB has the following lunar dust stimulant processing capabilities: heating and cooling while stirring in order to degas and remove absorbed water; RF air-plasma for activating the dust and for organic contaminant removal; RF H/He-plasma to simulate solar wind; dust sieving system for controlling particle sizes; and a controlled means of introducing the activated dust to the samples under study. The LDAB is also fitted with an in situ Xe arc lamp solar simulator, and a cold box that can reach 30 K. Samples of thermal control surfaces (2.5 cm diameter) are introduced into the chamber for calorimetric evaluation using thermocouple instrumentation. The object of this paper is to present a thermal model of the samples under test conditions, and to outline the procedure to extract the absorptance, emittance, and thermal efficiency from the pristine and sub-monolayer dust covered samples

Extraction of Thermal Performance Values from Samples in the Lunar Dust Adhesion Bell Jar

NASA Technical Reports Server (NTRS)

Gaier, James R.; Siamidis, John; Larkin, Elizabeth M. G.

2010-01-01

A simulation chamber has been developed to test the performance of thermal control surfaces under dusty lunar conditions. The lunar dust adhesion bell jar (LDAB) is a diffusion pumped vacuum chamber (10(exp -8) Torr) built to test material samples less than about 7 cm in diameter. The LDAB has the following lunar dust simulant processing capabilities: heating and cooling while stirring in order to degas and remove adsorbed water; RF air-plasma for activating the dust and for organic contaminant removal; RF H/He-plasma to simulate solar wind; dust sieving system for controlling particle sizes; and a controlled means of introducing the activated dust to the samples under study. The LDAB is also fitted with an in situ Xe arc lamp solar simulator, and a cold box that can reach 30 K. Samples of thermal control surfaces (2.5 cm diameter) are introduced into the chamber for calorimetric evaluation using thermocouple instrumentation. The object of this paper is to present a thermal model of the samples under test conditions and to outline the procedure to extract the absorptance, emittance, and thermal efficiency from the pristine and sub-monolayer dust covered samples.

76 FR 68385 - Approval and Promulgation of Implementation Plans; New Mexico; Albuquerque/Bernalillo County...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-04

... NMAC) addition of in subsections methodology for (A) and (B). fugitive dust control permits, revised... fee Fee Calculations and requirements for Procedures. fugitive dust control permits. 9/7/2004 Section... schedule based on acreage, add and update calculation methodology used to calculate non- programmatic dust...

Dust Emission at 8 and 24 μm as Diagnostics of H II Region Radiative Transfer

NASA Astrophysics Data System (ADS)

Oey, M. S.; López-Hernández, J.; Kellar, J. A.; Pellegrini, E. W.; Gordon, K. D.; Jameson, K. E.; Li, A.; Madden, S. C.; Meixner, M.; Roman-Duval, J.; Bot, C.; Rubio, M.; Tielens, A. G. G. M.

2017-07-01

We use the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) survey of the Magellanic Clouds to evaluate the relationship between the 8 μm polycyclic aromatic hydrocarbon (PAH) emission, 24 μm hot dust emission, and H II region radiative transfer. We confirm that in the higher-metallicity Large Magellanic Cloud, PAH destruction is sensitive to optically thin conditions in the nebular Lyman continuum: objects identified as optically thin candidates based on nebular ionization structure show six times lower median 8 μm surface brightness (0.18 mJy arcsec-2) than their optically thick counterparts (1.2 mJy arcsec-2). The 24 μm surface brightness also shows a factor of three offset between the two classes of objects (0.13 versus 0.44 mJy arcsec-2, respectively), which is driven by the association between the very small dust grains and higher density gas found at higher nebular optical depths. In contrast, PAH and dust formation in the low-metallicity Small Magellanic Cloud is strongly inhibited such that we find no variation in either 8 μm or 24 μm emission between our optically thick and thin samples. This is attributable to extremely low PAH and dust production together with high, corrosive UV photon fluxes in this low-metallicity environment. The dust mass surface densities and gas-to-dust ratios determined from dust maps using Herschel HERITAGE survey data support this interpretation.

Effect of soil texture and chemical properties on laboratory-generated dust emissions from SW North America

NASA Astrophysics Data System (ADS)

Mockford, T.; Zobeck, T. M.; Lee, J. A.; Gill, T. E.; Dominguez, M. A.; Peinado, P.

2012-12-01

Understanding the controls of mineral dust emissions and their particle size distributions during wind-erosion events is critical as dust particles play a significant impact in shaping the earth's climate. It has been suggested that emission rates and particle size distributions are independent of soil chemistry and soil texture. In this study, 45 samples of wind-erodible surface soils from the Southern High Plains and Chihuahuan Desert regions of Texas, New Mexico, Colorado and Chihuahua were analyzed by the Lubbock Dust Generation, Analysis and Sampling System (LDGASS) and a Beckman-Coulter particle multisizer. The LDGASS created dust emissions in a controlled laboratory setting using a rotating arm which allows particle collisions. The emitted dust was transferred to a chamber where particulate matter concentration was recorded using a DataRam and MiniVol filter and dust particle size distribution was recorded using a GRIMM particle analyzer. Particle size analysis was also determined from samples deposited on the Mini-Vol filters using a Beckman-Coulter particle multisizer. Soil textures of source samples ranged from sands and sandy loams to clays and silts. Initial results suggest that total dust emissions increased with increasing soil clay and silt content and decreased with increasing sand content. Particle size distribution analysis showed a similar relationship; soils with high silt content produced the widest range of dust particle sizes and the smallest dust particles. Sand grains seem to produce the largest dust particles. Chemical control of dust emissions by calcium carbonate content will also be discussed.

A preliminary study of the acaricidal activity of clove oil, Eugenia caryophyllus.

PubMed

Mahakittikun, Vanna; Soonthornchareonnon, Noppamas; Foongladda, Sooporn; Boitano, John Joseph; Wangapai, Teerapong; Ninsanit, Prapakorn

2014-03-01

The search for more eco-friendly acaricides has prompted testing of medicinal plants from botanical sources. To evaluate the eradication of house dust mites (HDM), Dermatophagoides pteronyssinus, by direct contact using the essential clove oil (Eugenia caryophyllus). A pilot study was initiated to determine the killing power of clove oil. Synthetic fibers were immersed in 2% clove oil for 30 min, dried in a hot air oven at 60°C for 2 hrs after which 0.5 gm of HDMs were exposed to these coated fibers placed in the Siriraj Chamber (SC). Two additional long-term methods were employed. Ten mites were placed in the SC and 10 μl of clove oil was pipetted or sprayed onto them. These latter two procedures were each carried out for 3 consecutive days at 0, 1, 3 and 6 months. The solutions antimicrobial and antifungal properties were evaluated by exposing common bacteria and fungi to sterile filter disks impregnated with the mixture, and after overnight incubation, the disc diffusion method on nutrient agar was used. Ethyl alcohol served as the placebo. 99% and 81%, respectively, while the placebo mortality was <5%. The zone of inhibition indicated significant clearance for all the bacteria and fungi indicating greater biocidal activity when compared to the controls. SEMs revealed dead mites on the fibers. The effectiveness of pipetting and spraying was 99% and 81%, respectively, while the placebo mortality was <5%. The zone of inhibition indicated significant clearance for all the bacteria and fungi indicating greater biocidal activity when compared to the controls. Clove oil is a promising agent for killing dust mites with a potential use in dust-mite laden mattresses. Spraying diminishes in efficiency after 3 months.

Physicochemical and microbiological characterization of cement kiln dust for potential reuse in wastewater treatment.

PubMed

Salem, W M; Sayed, W F; Halawy, S A; Elamary, R B

2015-09-01

Cement kiln dust (CKD), a byproduct of cement manufacturing process, was collected from Misr Cement Co. at Qena, Egypt. CKD was characterized by X-ray diffraction and FTIR analysis. This byproduct was investigated for its physical-chemical characters, antibacterial activities on sewage water and the presence of nematode, parasites and algae in the treated water. The efficiency of CKD-treated water was also examined on Hibiscus sabdarriffa seed germination. Total bacteria, total and fecal coliform, as well as fecal streptococci were completely inhibited by CKD. Interestingly, zinc, manganese, iron, nickel and lead were completely absent from sewage water as these metals precipitated after treatment with 10gl(-1) CKD. On the other hand, among all the tested plant criteria, only root length was significantly reduced by 55% and 15% after zero and 3 days of CKD addition respectively compared to control. Furthermore, plant lipid peroxidation showed no significant differences between treated sewage water and control after zero and 3 days time addition of CKD. Catalase enzyme activity showed significant decrease by 56% and 64%, while peroxidase activity significantly increased up to 49% and 63% compared to untreated sewage after zero and 3 days of treatment, respectively. The absorption of lead, iron and copper by treated and untreated plants showed no significant differences. Chromium ions were highly absorbed (0.075mgl(-1)) by plants irrigated only with treated sewage water at zero time, and decreased gradually to 0.018mgl(-1) after 3 days of CKD addition. This study highlighted the efficiency of cement kiln dust as an antibacterial agent and its ability of scavenging heavy metals leading to the use of treated sewage water in activities such as crop irrigation. Copyright © 2015 Elsevier Inc. All rights reserved.

Considerations on coal gasification

NASA Technical Reports Server (NTRS)

Franzen, J. E.

1978-01-01

Commercial processes for the gasification of coal with oxygen are discussed. The Koppers-Totzek process for the gasification of coal dust entrained in a stream of gasifying agents is described in particular detail. The outlook for future applications of coal gasification is presented.

The impacts of the axial-to-radial airflow quantity ratio and suction distance on air curtain dust control in a fully mechanized coal face.

PubMed

Wang, Hao; Cheng, Weimin; Sun, Biao; Yu, Haiming; Jin, Hu

2018-03-01

To understand the impacts of the axial-to-radial airflow quantity ratio (denoted as R) and the suction distance (denoted as D s ) on air curtain dust control in a fully mechanized coal face, the 3 down 610 coal face in Jiangzhuang coal mine was numerically simulated in this study. A mathematic model was established to describe the airflow migration and dust diffusion in a coal face, and a scaled physical model was constructed. The comparison between simulation results and field measurements validated the model and the parameter settings. Furthermore, the airflow migration and dust diffusion at various R and D s are analyzed using Ansys CFD. The results show that a reduction of R and D s is conducive to the formation of an effective axial dust control air curtain; the dust diffusion distance decreases with the decrease of both R and D s . By analyzing the simulation results, the optimal parameter for air curtain dust control in the 3 down 610 coal face and those faces with similar production conditions is determined as R = 1/9 and D s  = 2 m. Under the optimal parameter condition, the high-concentration dust can be confined in front of the mining driver within a space 5.8 m away from the coal face.

[Dust concentration analysis in non-coal mining. Exposure evaluation based on measurements performed by occupational hygiene laboratories in the years 2001-2005 in Poland].

PubMed

Bujak-Pietrek, Stella; Mikołajczyk, Urszula; Szadkowska-Stańczyk, Irena

2011-01-01

Non-coal mining includes the extraction of materials for construction (stone, gravel, sand and clay), chemical industry (salt and sulfur), metallurgy (metal ores, uranium and thorium) and other mining and quarrying. Regardless of the type of mining company one of the most common health hazards in this sector is exposure to high concentrations of dust occurring during the extraction of materials. Such activities as drilling, use of blasting agents, processing of raw material, its transportation and loading are the source of large amounts of dust containing crystalline silica. Data on exposure to dust, collected by industrial hygiene laboratories on the basis of dust concentration measurements in the work environment, were obtained from the sanitary inspection service. The analysis of dust concentrations at workplaces in non-coal mining covered the years 2001-2005. The average concentration of inhalable and respirable dust and the degree of results dispersion at workposts in different branches of non-coal mining (according to NACE rev1.1) were evaluated. Also there was estimated the percentage of surveys indicating dust concentrations above hygiene standards. Almost 5000 measurements of dust concentrations were performed in the years under study. The highest concentration of inhalable dust was noted for the production of salt (5.51 mg/m3), other mining and quarrying (4.30 mg/m3) and quarrying of slate (3.77 mg/m3). For respirable dust the highest concentrations were noted in other mining and quarrying (1.10 mg/m3), quarrying of slate (1.09 mg/m3) and quarrying of stone (0.81 mg/m3). Exposure to high concentrations of dust during the extraction of non-carbon is still an important hazard to human health. Almost for all workposts under study the excess of hygiene standards were observed.

Effect of ecological restoration programs on dust concentrations in the North China Plain: a case study

NASA Astrophysics Data System (ADS)

Long, Xin; Tie, Xuexi; Li, Guohui; Cao, Junji; Feng, Tian; Zhao, Shuyu; Xing, Li; An, Zhisheng

2018-05-01

In recent decades, the Chinese government has made a great effort in initiating large-scale ecological restoration programs (ERPs) to reduce the dust concentrations in China, especially for dust storm episodes. Using the Moderate Resolution Imaging Spectroradiometer (MODIS) land cover product, the ERP-induced land cover changes are quantitatively evaluated in this study. Two obvious vegetation protective barriers arise throughout China from the southwest to the northeast, which are well known as the Green Great Wall (GGW). Both the grass GGW and forest GGW are located between the dust source region (DSR) and the densely populated North China Plain (NCP). To assess the effect of ERPs on dust concentrations, a regional transport/dust model (WRF-DUST, Weather Research and Forecast model with dust) is applied to investigate the evolution of dust plumes during a strong dust storm episode from 2 to 8 March 2016. The WRF-DUST model generally performs reasonably well in reproducing the temporal variations and spatial distributions of near-surface [PMC] (mass concentration of particulate matter with aerodynamic diameter between 2.5 and 10 µm) during the dust storm event. Sensitivity experiments have indicated that the ERP-induced GGWs help to reduce the dust concentration in the NCP, especially in BTH (Beijing, Tianjin, and Hebei). When the dust storm is transported from the upwind DSR to the downwind NCP, the [PMC] reduction ranges from -5 to -15 % in the NCP, with a maximum reduction of -12.4 % (-19.2 µg m-3) in BTH and -7.6 % (-10.1 µg m-3) in the NCP. We find the dust plumes move up to the upper atmosphere and are transported from the upwind DSR to the downwind NCP, accompanied by dust decrease. During the episode, the forest GGW is nonsignificant in dust concentration control because it is of benefit for dry deposition and not for emission. Conversely, the grass GGW is beneficial in controlling dust erosion and is the dominant reason for [PMC] decrease in the NCP. Because the air pollution is severe in eastern China, especially in the NCP, and the contribution of dust episodes is significant, the reduction of dust concentrations will have important effects on severe air pollution. This study illustrates the considerable contribution of ERPs to the control of air pollution in China, especially in springtime.

Dust control products at Hagerman National Wildlife Refuge, Texas: environmental safety and performance

USGS Publications Warehouse

Kunz, Bethany K.; Little, Edward E.

2015-01-01

Controlling fugitive dust while protecting natural resources is a challenge faced by all managers of unpaved roads. Unfortunately, road managers choosing between dust control products often have little objective environmental information to aid their decisions. To address this information gap, the U.S. Geological Survey and the U.S. Fish and Wildlife Service collaborated on a field test of three dust control products with the objectives of (a) evaluating product performance under real-world conditions, (b) verifying the environmental safety of products identified as practically nontoxic in laboratory tests, and (c) testing the feasibility of several environmental monitoring techniques for use in dust control tests. In cooperation with refuge staff and product vendors, three products (one magnesium chloride plus binder, one cellulose, and one synthetic fluid plus binder) were applied in July 2012 to replicated road sections at the Hagerman National Wildlife Refuge in Texas. These sections were monitored periodically for 12 months after application. Product performance was assessed by mobile-mounted particulate-matter meters measuring production of fugitive dust and by observations of road conditions. Environmental safety was evaluated through on-site biological observations and leaching tests with samples of treated aggregate. All products reduced dust and improved surface condition during those 12 months. Planned environmental measurements were not always compatible with day-to-day refuge management actions; this incompatibility highlighted the need for flexible biological monitoring plans. As one of the first field tests of dust suppressants that explicitly incorporated biological endpoints, this effort provides valuable information for improving field tests and for developing laboratory or semifield alternatives.

Characterization of airborne float coal dust emitted during continuous mining, longwall mining and belt transport.

PubMed

Shahan, M R; Seaman, C E; Beck, T W; Colinet, J F; Mischler, S E

2017-09-01

Float coal dust is produced by various mining methods, carried by ventilating air and deposited on the floor, roof and ribs of mine airways. If deposited, float dust is re-entrained during a methane explosion. Without sufficient inert rock dust quantities, this float coal dust can propagate an explosion throughout mining entries. Consequently, controlling float coal dust is of critical interest to mining operations. Rock dusting, which is the adding of inert material to airway surfaces, is the main control technique currently used by the coal mining industry to reduce the float coal dust explosion hazard. To assist the industry in reducing this hazard, the Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health initiated a project to investigate methods and technologies to reduce float coal dust in underground coal mines through prevention, capture and suppression prior to deposition. Field characterization studies were performed to determine quantitatively the sources, types and amounts of dust produced during various coal mining processes. The operations chosen for study were a continuous miner section, a longwall section and a coal-handling facility. For each of these operations, the primary dust sources were confirmed to be the continuous mining machine, longwall shearer and conveyor belt transfer points, respectively. Respirable and total airborne float dust samples were collected and analyzed for each operation, and the ratio of total airborne float coal dust to respirable dust was calculated. During the continuous mining process, the ratio of total airborne float coal dust to respirable dust ranged from 10.3 to 13.8. The ratios measured on the longwall face were between 18.5 and 21.5. The total airborne float coal dust to respirable dust ratio observed during belt transport ranged between 7.5 and 21.8.

Hydrothermal Alteration Products as Key to Formation of Duricrust and Rock Coatings on Mars

NASA Astrophysics Data System (ADS)

Bishop, J. L.

1999-03-01

A model is presented for the formation of duricrust and rock coatings on Mars. Hydrothermal alteration of volcanic tephra may produce a corrosive agent that attacks rock surfaces and binds dust particles to form duricrust.

House dust mite barrier bedding for childhood asthma: randomised placebo controlled trial in primary care [ISRCTN63308372].

PubMed

Sheikh, Aziz; Hurwitz, Brian; Sibbald, Bonnie; Barnes, Greta; Howe, Maggie; Durham, Stephen

2002-06-18

The house dust mite is the most important environmental allergen implicated in the aetiology of childhood asthma in the UK. Dust mite barrier bedding is relatively inexpensive, convenient to use, and of proven effectiveness in reducing mattress house dust mite load, but no studies have evaluated its clinical effectiveness in the control of childhood asthma when dispensed in primary care. We therefore aimed to evaluate the effectiveness of house dust mite barrier bedding in children with asthma treated in primary care. Pragmatic, randomised, double-blind, placebo controlled trial conducted in eight family practices in England. Forty-seven children aged 5 to 14 years with confirmed house dust mite sensitive asthma were randomised to receive six months treatment with either house dust mite barrier or placebo bedding. Peak expiratory flow was the main outcome measure of interest; secondary outcome measures included asthma symptom scores and asthma medication usage. No difference was noted in mean monthly peak expiratory flow, asthma symptom score, medication usage or asthma consultations, between children who received active bedding and those who received placebo bedding. Treating house dust mite sensitive asthmatic children in primary care with house dust mite barrier bedding for six months failed to improve peak expiratory flow. Results strongly suggest that the intervention made no impact upon other clinical features of asthma.

House dust mite barrier bedding for childhood asthma: randomised placebo controlled trial in primary care [ISRCTN63308372

PubMed Central

Sheikh, Aziz; Hurwitz, Brian; Sibbald, Bonnie; Barnes, Greta; Howe, Maggie; Durham, Stephen

2002-01-01

Background The house dust mite is the most important environmental allergen implicated in the aetiology of childhood asthma in the UK. Dust mite barrier bedding is relatively inexpensive, convenient to use, and of proven effectiveness in reducing mattress house dust mite load, but no studies have evaluated its clinical effectiveness in the control of childhood asthma when dispensed in primary care. We therefore aimed to evaluate the effectiveness of house dust mite barrier bedding in children with asthma treated in primary care. Methods Pragmatic, randomised, double-blind, placebo controlled trial conducted in eight family practices in England. Forty-seven children aged 5 to 14 years with confirmed house dust mite sensitive asthma were randomised to receive six months treatment with either house dust mite barrier or placebo bedding. Peak expiratory flow was the main outcome measure of interest; secondary outcome measures included asthma symptom scores and asthma medication usage. Results No difference was noted in mean monthly peak expiratory flow, asthma symptom score, medication usage or asthma consultations, between children who received active bedding and those who received placebo bedding. Conclusions Treating house dust mite sensitive asthmatic children in primary care with house dust mite barrier bedding for six months failed to improve peak expiratory flow. Results strongly suggest that the intervention made no impact upon other clinical features of asthma. PMID:12079502

SPARCLE: Electrostatic Dust Control Tool Proof of Concept

NASA Technical Reports Server (NTRS)

Clark, P. E.; Curtis, S. A.; Minetto, F.; Marshall, J.; Nuth, J.; Calle, C.

2010-01-01

Successful exploration of most planetary surfaces, with their impact-generated dusty regoliths, will depend on the capabilities to keep surfaces free of the performance-compromising dust. Once in contact with surfaces, whether set in motion by natural or mechanical means, regolith fines, or dust, behave like abrasive Velcro, coating surfaces, clogging mechanisms, making movement progressively more difticult, and being almost impossible to remove by mechanical mcans (brushing). The successful dust removal strategy will deal with dust dynamics resulting from interaction between Van der Waals and Coulombic forces. Here, proof of concept for an electrostatically-based concept for dust control tool is described and demonstrated. A low power focused electron beam is used in the presence of a small electrical field to increase the negative charge to mass ratio of a dusty surface until dust repulsion and attraction to a lower potential surface, acting as a dust collector, occurred. Our goal is a compact device of less than 5 kg mass and using less than 5 watts of power to be operational in less than 5 years with heritage from ionic sweepers for active spacecraft potential control (e.g ., on POLAR). Rovers could be fitted with devices that could hamess the removal of dust for sampling as part of the extended exploration process on Mercury, Mars, asteroids or outer solar system satellites, as well as the Moon.

Real-time measurement of dust in the workplace using video exposure monitoring: Farming to pharmaceuticals

NASA Astrophysics Data System (ADS)

Walsh, P. T.; Forth, A. R.; Clark, R. D. R.; Dowker, K. P.; Thorpe, A.

2009-02-01

Real-time, photometric, portable dust monitors have been employed for video exposure monitoring (VEM) to measure and highlight dust levels generated by work activities, illustrate dust control techniques, and demonstrate good practice. Two workplaces, presenting different challenges for measurement, were used to illustrate the capabilities of VEM: (a) poultry farming activities and (b) powder transfer operations in a pharmaceutical company. For the poultry farm work, the real-time monitors were calibrated with respect to the respirable and inhalable dust concentrations using cyclone and IOM reference samplers respectively. Different rankings of exposure for typical activities were found on the small farm studied here compared to previous exposure measurements at larger poultry farms: these were mainly attributed to the different scales of operation. Large variations in the ratios of respirable, inhalable and real-time monitor TWA concentrations of poultry farm dust for various activities were found. This has implications for the calibration of light-scattering dust monitors with respect to inhalable dust concentration. In the pharmaceutical application, the effectiveness of a curtain barrier for dust control when dispensing powder in a downflow booth was rapidly demonstrated.

Reducing float coal dust

PubMed Central

Patts, J.R.; Colinet, J.F.; Janisko, S.J.; Barone, T.L.; Patts, L.D.

2016-01-01

Controlling float coal dust in underground coal mines before dispersal into the general airstream can reduce the risk of mine explosions while potentially achieving a more effective and efficient use of rock dust. A prototype flooded-bed scrubber was evaluated for float coal dust control in the return of a continuous miner section. The scrubber was installed inline between the face ventilation tubing and an exhausting auxiliary fan. Airborne and deposited dust mass measurements were collected over three days at set distances from the fan exhaust to assess changes in float coal dust levels in the return due to operation of the scrubber. Mass-based measurements were collected on a per-cut basis and normalized on the basis of per ton mined by the continuous miner. The results show that average float coal dust levels measured under baseline conditions were reduced by more than 90 percent when operating the scrubber. PMID:28018004

75 FR 38745 - Approval and Promulgation of Implementation Plans; State of Iowa

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-06

... methods for the containment and control of fugitive dust, and subsections 5-23(7) and 5-23(8) were added to include methods for the containment and control of fugitive dust. Changes to Section 5-25 clarify that no person shall cause, allow, or permit fugitive dust material to become airborne in such...

Life cycle and reproduction of house-dust mites: environmental factors influencing mite populations.

PubMed

Hart, B J

1998-01-01

An understanding of the life cycle of house-dust mites, as well as environmental factors influencing mite populations, can be exploited in mite control. The most important limiting factor for house-dust-mite populations is air humidity. House-dust mites osmoregulate through the cuticle and therefore require a high ambient air humidity to prevent excessive water loss. In addition, the supracoxal glands actively take up ambient water vapour, and the protonynph stage of the life cycle is resistant to desiccation. Larger house-dust-mite populations are found when the absolute indoor air humidity is above 7 g/kg (45% relative humidity at 20 degrees C). Consequently, ventilation by air-conditioning systems is being developed as a means of control. A number of other aspects of the domestic environment are also being manipulated in an integrated approach to render the habitat less suitable for mites. The potential exists for developing models for house-dust mite populations, environmental characteristics, and the effects of various approaches to control.

Developing a new controllable lunar dust simulant: BHLD20

NASA Astrophysics Data System (ADS)

Sun, Hao; Yi, Min; Shen, Zhigang; Zhang, Xiaojing; Ma, Shulin

2017-07-01

Identifying and eliminating the negative effects of lunar dust are of great importance for future lunar exploration. Since the available lunar samples are limited, developing terrestrial lunar dust simulant becomes critical for the study of lunar dust problem. In this work, beyond the three existing lunar dust simulants: JSC-1Avf, NU-LHT-1D, and CLDS-i, we developed a new high-fidelity lunar dust simulant named as BHLD20. And we concluded a methodology that soil and dust simulants can be produced by variations in portions of the overall procedure, whereby the properties of the products can be controlled by adjusting the feedstock preparation and heating process. The key ingredients of our innovative preparation route include: (1) plagioclase, used as a major material in preparing all kinds of lunar dust simulants; (2) a muffle furnace, applied to expediently enrich the glass phase in feedstock, with the production of some composite particles; (3) a one-step sand-milling technique, employed for mass pulverization without wasting feedstock; and (4) a particle dispersant, utilized to prevent the agglomeration in lunar dust simulant and retain the real particle size. Research activities in the development of BHLD20 can help solve the lunar dust problem.

Dust Emission at 8 and 24 μ m as Diagnostics of H ii Region Radiative Transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oey, M. S.; López-Hernández, J.; Kellar, J. A.

We use the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) survey of the Magellanic Clouds to evaluate the relationship between the 8 μ m polycyclic aromatic hydrocarbon (PAH) emission, 24 μ m hot dust emission, and H ii region radiative transfer. We confirm that in the higher-metallicity Large Magellanic Cloud, PAH destruction is sensitive to optically thin conditions in the nebular Lyman continuum: objects identified as optically thin candidates based on nebular ionization structure show six times lower median 8 μ m surface brightness (0.18 mJy arcsec{sup −2}) than their optically thick counterparts (1.2 mJy arcsec{sup −2}). The 24more » μ m surface brightness also shows a factor of three offset between the two classes of objects (0.13 versus 0.44 mJy arcsec{sup −2}, respectively), which is driven by the association between the very small dust grains and higher density gas found at higher nebular optical depths. In contrast, PAH and dust formation in the low-metallicity Small Magellanic Cloud is strongly inhibited such that we find no variation in either 8 μ m or 24 μ m emission between our optically thick and thin samples. This is attributable to extremely low PAH and dust production together with high, corrosive UV photon fluxes in this low-metallicity environment. The dust mass surface densities and gas-to-dust ratios determined from dust maps using Herschel HERITAGE survey data support this interpretation.« less

Atopy patch test reactions to house dust mites in patients with scabies.

PubMed

Taşkapan, Oktay; Harmanyeri, Yavuz

2005-01-01

It is well known that the house dust and the scabies mites are related phylogenetically. We therefore performed atopy patch tests with house dust mite antigens (Dermatophagoides pteronyssinus (Dp) and/or Dermatophagoides farinae (Df)) in scabies patients without atopy and healthy controls. We studied 25 men with active scabies and 25 healthy controls. Skin prick tests with standardized house dust mite extract were performed for all patients and controls. An intradermal test procedure was carried out in skin prick test-negative patients, and for controls showing positive atopy patch test to Dp and/or Df. While atopy patch tests were performed directly in all healthy controls, patients with scabies were first treated and on the next day, atopy patch tests were performed. Twenty-two of 25 patients with scabies (88%) had skin prick test and/or intradermal test positivity against house dust mites, whereas 17/25 patients (68%) had atopy patch test positivity against house dust mites (Dp and/or Df). There was no statistically significant difference between skin prick test and/or intradermal test positivity and atopy patch test positivity in a regression analysis (p=0.222). The only statistically significant correlation was between atopy patch test positivity and the extent of scabies involvement (p<0.05). Only few of the healthy controls had positive tests. In this study, we have shown that a positive atopy patch test to house dust mite antigens is not specific for patients with atopic dermatitis, but also occurs in scabies patients without a history of atopic dermatitis.

Kawasaki syndrome: a controlled study of an outbreak in Wisconsin.

PubMed

Klein, B S; Rogers, M F; Patrican, L A; White, M C; Burgdorfer, W; Schell, W L; Kochel, R L; Marchette, N J; McPherson, J T; Nelson, D B

1986-08-01

The etiology of Kawasaki syndrome remains unestablished, although a possible role has been suggested for exposure to the application of carpet shampoo, house dust mites, and rickettsial infection. During an outbreak of 20 cases of Kawasaki syndrome that occurred in southeastern Wisconsin from November 1982 through March 1983, a case-control study was done of 15 cases and 30 matched controls. The study included questionnaire administration, dust collection from homes, and serum specimen collection. Only one patient had been exposed to a shampooed carpet within 30 days before onset of illness. No differences were noted between cases and controls in the degree of exposure to house dust mite-associated factors in the home, nor in the occurrence, density and species-specific prevalence of house dust mites in the home. Meadow voles exposed to house dust mites from the homes of patients did not develop serologic or pathologic evidence of infection due to rickettsiae in the spotted fever and typhus groups or Coxiella burnetii. Anti-mite-specific immunoglobulin E was not detected in serum specimens from cases or controls. Results from this study do not support hypotheses suggesting that the development of Kawasaki syndrome is associated with exposure to application of carpet shampoo, house dust mites, or rickettsial infection.

Dust control technology usage patterns in the drywall finishing industry.

PubMed

Young-Corbett, Deborah E; Nussbaum, Maury A

2009-06-01

A telephone survey was conducted to quantify drywall finishing industry usage rates of dust control technology, identify barriers to technology adoption, and explore firm owner perception of risk. Industry use of the following technologies was described: wet methods, respiratory protection, pole sanders, ventilated sanders, and low-dust joint compound. A survey instrument composed of both Likert-type scaled items and open-ended items was developed and administered by telephone to the census population of the owners of member firms of trade associations: Finishing Contractors Association and Association of the Wall and Ceiling Industries. Of 857 firms, 264 interviews were completed. Along with descriptive statistics, results were analyzed to examine effects of firm size and union affiliation on responses. Responses to open-ended items were analyzed using content analysis procedures. Firm owners rated the risk of dust to productivity and customer satisfaction as low-moderate. Half rated the dust as having some impact on worker health, with higher impacts indicated by owners of small firms. Among the available control technologies, respiratory protection was used most frequently. Several barriers to implementation of the more effective control technologies were identified. Barriers associated with technology usability, productivity, and cost, as well as misperceptions of risk, should be addressed to improve dust control in the drywall finishing industry.

The Electrostatic Environments of Mars: Atmospheric Discharges

NASA Technical Reports Server (NTRS)

Calle, Carlos I.; Mackey, Paul J.; Johansen, Michael R.; Hogue, Michael D.; Phillips, James, III; Cox, Rachel E.

2016-01-01

The electrostatic environment on Mars is controlled by its ever present atmospheric dust. Dust devils and dust storms tribocharge this dust. Theoretical studies predict that lightning and/or glow discharges should be present on Mars, but none have been directly observed. Experiments are planned to shed light on this issue.

Fogging formulations for fixation of particulate contamination in ductwork and enclosures

DOEpatents

Maresca, Jr., Joseph W.; Kostelnik, Lori M.; Kriskivich, James R.; Demmer, Rick L.; Tripp, Julia L.

2015-09-08

A method and an apparatus using aqueous fixatives for fogging of ventilation ductwork, enclosures, or buildings containing dust, lint, and particulates that may be contaminated by radionuclides and other dangerous or unsafe particulate contaminants, which method and apparatus are capable of (1) obtaining full coverage within the ductwork and (2) penetrating and fixing the lint, dust and large particles present in the ductwork so that no airborne particles are released during or after the application of the fixative. New aqueous fogging solutions outperform conventional glycerin-based solutions. These aqueous solutions will fog using conventional methods of application and contain a surfactant to aid wetting and penetration of the lint and dust, a binder to stabilize loose or respirable particles, and an agent to aid in fogging and enhance adhesiveness. The solutions are safe and easy to use.

Desquamative interstitial pneumonia associated with chrysotile asbestos fibres.

PubMed Central

Freed, J A; Miller, A; Gordon, R E; Fischbein, A; Kleinerman, J; Langer, A M

1991-01-01

The drywall construction trade has in the past been associated with exposure to airborne asbestos fibres. This paper reports a drywall construction worker with 32 years of dust exposure who developed dyspnoea and diminished diffusing capacity, and showed diffuse irregular opacities on chest radiography. He did not respond to treatment with corticosteroids. Open lung biopsy examination showed desquamative interstitial pneumonia. Only a single ferruginous body was seen on frozen section, but tissue examination by electron microscopy showed an extraordinary pulmonary burden of mineral dust with especially high concentrations of chrysotile asbestos fibres. This report emphasises the need to consider asbestos fibre as an agent in the aetiology of desquamative interstitial pneumonia. The coexistent slight interstitial fibrosis present in this case is also considered to have resulted from exposure to mineral dust, particularly ultramicroscopic asbestos fibres. Images PMID:1645584

Evaluation of Brushing as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

NASA Technical Reports Server (NTRS)

Gaier, James R.; Journey, Khrissaundra; Christopher, Steven; Davis, Shanon

2011-01-01

Evaluation of brushing to remove lunar simulant dust from thermal control surfaces is described. First, strip brushes made with nylon, PTFE, or Thunderon (Nihon Sanmo Dyeing Company Ltd.) bristles were used to remove JSC-1AF dust from AZ93 thermal control paint or aluminized FEP (AlFEP) thermal control surface under ambient laboratory conditions. Nylon and PTFE bristles removed a promising amount of dust from AZ93, and nylon and Thunderon bristles from AlFEP. But when these were tested under simulated lunar conditions in the lunar dust adhesion bell jar (LDAB), they were not effective. In a third effort, seven brushes made up of three different materials, two different geometries, and different bristle lengths and thicknesses were tested under laboratory conditions against AZ93 and AlFEP. Two of these brushes, the Zephyr fiberglass fingerprint brush and the Escoda nylon fan brush, removed over 90 percent of the dust, and so were tested in the fourth effort in the LDAB. They also performed well under these conditions recovering 80 percent or more of the original thermal performance (solar absorptance/thermal emittance) of both AZ93 and AgFEP after 20 strokes, and 90 or more percent after 200 strokes

Evaluation of Brushing as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

NASA Technical Reports Server (NTRS)

Gaier, James R.; Journey, Hhrissaundra; Christopher, Steven; Davis, Shanon

2011-01-01

Evaluation of brushing to remove lunar simulant dust from thermal control surfaces is described. First, strip brushes made with nylon, PTFE, or Thunderon bristles were used to remove JSC-1AF dust from AZ93 thermal control paint or aluminized FEP (AlFEP) thermal control surface under ambient laboratory conditions. Nylon and PTFE bristles removed a promising amount of dust from AZ93, and nylon and Thunderon bristles from AlFEP. But when these were tested under simulated lunar conditions in the lunar dust adhesion bell jar (LDAB), they were not effective. In a third effort, seven brushes made up of three different materials, two different geometries, and different bristle lengths and thicknesses were tested under laboratory conditions against AZ93 and AlFEP. Two of these brushes, the Zephyr fiberglass fingerprint brush and the Escoda nylon fan brush, removed over 90 percent of the dust, and so were tested in the fourth effort in the LDAB. They also performed well under these conditions recovering 80 percent or more of the original thermal performance (solar absorptance/thermal emittance) of both AZ93 and AgFEP after 20 strokes, and 90 or more percent after 200 strokes.

Wood-related occupations, wood dust exposure, and sinonasal cancer.

PubMed

Hayes, R B; Gerin, M; Raatgever, J W; de Bruyn, A

1986-10-01

A case-control study was conducted to examine the relations between type of woodworking and the extent of wood dust exposure to the risks for specific histologic types of sinonasal cancer. In cooperation with the major treatment centers in the Netherlands, 116 male patients newly diagnosed between 1978 and 1981 with primary malignancies of epithelial origin of this site were identified for study. Living controls were selected from the municipal registries, and deceased controls were selected from the national death registry. Interviews were completed for 91 (78%) cases and 195 (75%) controls. Job histories were coded by industry and occupation. An index of exposure was developed to classify the extent of occupational exposure to wood dust. When necessary, adjustment was made for age and usual cigarette use. The risk for nasal adenocarcinoma was elevated by industry for the wood and paper industry (odds ratio (OR) = 11.9) and by occupation for those employed in furniture and cabinet making (OR = 139.8), in factory joinery and carpentry work (OR = 16.3), and in association with high-level wood dust exposure (OR = 26.3). Other types of nasal cancer were not found to be associated with wood-related industries or occupations. A moderate excess in risk for squamous cell cancer (OR = 2.5) was associated with low-level wood dust exposure; however, no dose-response relation was evident. The association between wood dust and adenocarcinoma was strongest for those employed in wood dust-related occupations between 1930 and 1941. The risk of adenocarcinoma did not appear to decrease for at least 15 years after termination of exposure to wood dust. No cases of nasal adenocarcinoma were observed in men whose first exposure to wood dust occurred after 1941.

Dust control for Enabler

NASA Technical Reports Server (NTRS)

Hilton, Kevin; Karl, Chad; Litherland, Mark; Ritchie, David; Sun, Nancy

1992-01-01

The dust control group designed a system to restrict dust that is disturbed by the Enabler during its operation from interfering with astronaut or camera visibility. This design also considers the many different wheel positions made possible through the use of artinuation joints that provide the steering and wheel pitching for the Enabler. The system uses a combination of brushes and fenders to restrict the dust when the vehicle is moving in either direction and in a turn. This design also allows for each of maintenance as well as accessibility of the remainder of the vehicle.

Dust control for Enabler

NASA Technical Reports Server (NTRS)

Hilton, Kevin; Karl, Chad; Litherland, Mark; Ritchie, David; Sun, Nancy

1992-01-01

The dust control group designed a system to restrict dust that is disturbed by the Enabler during its operation from interfering with astronaut or camera visibility. This design also considers the many different wheel positions made possible through the use of artinuation joints that provide the steering and wheel pitching for the Enabler. The system uses a combination of brushes and fenders to restrict the dust when the vehicle is moving in either direction and in a turn. This design also allows for ease of maintenance as well as accessibility of the remainder of the vehicle.

Respirable dust measured downwind during rock dust application.

PubMed

Harris, M L; Organiscak, J; Klima, S; Perera, I E

2017-05-01

The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

EVALUATION OF THE PULMONARY TOXICITY OF AMBIENT PARTICULATE MATTER FROM CAMP VICTORY, IRAQ

PubMed Central

Porter, K. L.; Green, F. H. Y.; Harley, R. A.; Vallyathan, V.; Castranova, V.; Waldron, N. R.; Leonard, S. S.; Nelson, D. E.; Lewis, J. A.; Jackson, D. A.

2016-01-01

Anecdotal reports in the press and epidemiological studies suggest that deployment to Iraq and Afghanistan may be associated with respiratory diseases and symptoms in U.S. military personnel and veterans. Exposures during military operations were complex, but virtually all service members were exposed to high levels of respirable, geogenic dust. Inhalation of other dusts has been shown to be associated with adverse health effects, but the pulmonary toxicity of ambient dust from Iraq has not been previously studied. The relative toxicity of Camp Victory dust was evaluated by comparing it to particulate matter from northern Kuwait, a standard U.S. urban dust, and crystalline silica using a single intratracheal instillation in rats. Lung histology, protein levels, and cell counts were evaluated in the bronchoalveolar lavage fluid 1–150 d later. The Iraq dust provoked an early significant, acute inflammatory response. However, the level of inflammation in response to the Iraq dust, U.S. urban dust, and Kuwait dust rapidly declined and was nearly at control levels by the end of the study At later times, animals exposed to the Iraq, U.S. urban, or Kuwait dusts showed increased small airway remodeling and emphysema compared to silica-exposed and control animals without evidence of fibrosis or premalignant changes. The severity and persistence of pulmonary toxicity of these three dusts from the Middle East resemble those of a U.S. urban dust and are less than those of silica. Therefore, Iraq dust exposure is not highly toxic, but similar to other poorly soluble low-toxicity dusts. PMID:26594896

DNA Damage among Wood Workers Assessed with the Comet Assay

PubMed Central

Bruschweiler, Evin Danisman; Wild, Pascal; Huynh, Cong Khanh; Savova-Bianchi, Dessislava; Danuser, Brigitta; Hopf, Nancy B.

2016-01-01

Exposure to wood dust, a human carcinogen, is common in wood-related industries, and millions of workers are occupationally exposed to wood dust worldwide. The comet assay is a rapid, simple, and sensitive method for determining DNA damage. The objective of this study was to investigate the DNA damage associated with occupational exposure to wood dust using the comet assay (peripheral blood samples) among nonsmoking wood workers (n = 31, furniture and construction workers) and controls (n = 19). DNA damage was greater in the group exposed to composite wood products compared to the group exposed to natural woods and controls (P < 0.001). No difference in DNA damage was observed between workers exposed to natural woods and controls (P = 0.13). Duration of exposure and current dust concentrations had no effect on DNA damage. In future studies, workers’ exposures should include cumulative dust concentrations and exposures originating from the binders used in composite wood products. PMID:27398027

[Prevalence of sensitization to allergens in school children with asthma residents from Guadalajara metropolitan area].

PubMed

Alcalá-Padilla, Guadalupe; Bedolla-Barajas, Martín; Kestler-Gramajo, Amanda; Valdez-López, Francisco

2016-01-01

Allergic sensitization is dependent on the geographical and climatic conditions in each region; therefore, identify agents most commonly sensitized children with asthma is important for planning prevention measures. To determine the prevalence of the sensitization to allergens in children with asthma. This cross-sectional and prolective study includes children from ages 6 to 14, who have asthma, attended for the first time in an allergy service. The patients were recruited consecutively between the months of January 1st 2014 to December 31st 2014. The frequency of the allergen sensitization was estimated. This study included 186 children, the median age was 7 years olds, the male group was 104/186 (55.9%) The median of the positive results was 5 and monosensitized were 47/186 (2.2%). The most common category of allergens was the indoor (90.3%), then trees (71.0%), and finally the fungi (9.7%). Individually, the house dust mites were more common in between the interior allergens, followed by the epithelial; in the tree pollen were oaks (31.7%) and ashes (28.0%), in weeds was mugwort (21.5%), in grasses was Zea mays (18.3%) and in the fungi was Cladosporium spp. (6.5%). The high prevalence of the sensitization to house dust mites and epithelial in children with asthma, stimulates to implement methods of environmental control for contributing a better control of the disease.

Preliminary study on immobilization of buffing dust by solidification method in ceramic brick

NASA Astrophysics Data System (ADS)

Yuliansyah, Ahmad Tawfiequrrahman; Prasetya, Agus; Putra, Arif Eka; Satriawan, Humam Budi

2017-11-01

Leather-based industries generate a substantial amount of hazardous solid and liquid wastes in their process. One of the solid wastes is buffing dust, which is fine particulates containing fat, tanning, dyes and chromium. From 1 ton of leather processed, approximately 2-6 kg of buffing dust is generated. Chromium in the buffing dust is carcinogenic, so a proper handling is highly required. Solidification is a method commonly used to immobilize toxic material. Hence, the material is trapped in a matrix made of binding agents to minimize its mobility. However, a very small amount of the materials is sometimes released to the environment during storage. This study investigates leaching process of chromium from immobilized buffing dust in ceramic brick. Buffing dust, which contains chromium, is solidified by mixing it with clay at certain compositions and fired in a muffle furnace to produce a ceramic brick. Performance of the solidification process is evaluated by measuring the leaching of chromium in the leaching test. The results show that the solidification has significantly reduced the potential release of chromium to the environment. Higher of the firing temperature, less chromium is leached from ceramic brick. The chromium concentration of leachate water from 800°C brick is 0.376 ppm, while those from 850 and 900°C brick are 0.212 and 0.179 ppm respectively.

TRAFFIC-RELATED AIR POLLUTANTS AND CHILDREN'S RESPIRATORY HEALTH IN EL PASO AND DETROIT

EPA Science Inventory

Hypotheses -Specific Agent • Diesel exhaust particles • Ultrafine particles • Coarse-mode particles (road dust) • Noise and stress • Nonspecific irritants Previous Epidemiology • Kanawha Valley Health Study • Munich Traffic Study • Dutch Traffic Studies • S....

Guidelines for the Use of Synthetic Fluid Dust Control Palliatives on Unpaved Roads

DOT National Transportation Integrated Search

2017-07-01

The amount of small soil particles, dust, lost from typical unpaved roads to fugitive dust is staggering. A 1 km stretch of unpaved road can contribute over 2400 kg of dust to the atmosphere (4.2 ton/mile) in a typical 3-month summer season. Road man...

Aeolian controls of soil geochemistry and weathering fluxes in high-elevation ecosystems of the Rocky Mountains, Colorado

USGS Publications Warehouse

Lawrence, Corey R.; Reynolds, Richard L.; Kettterer, Michael E.; Neff, Jason C.

2013-01-01

When dust inputs are large or have persisted for long periods of time, the signature of dust additions are often apparent in soils. The of dust will be greatest where the geochemical composition of dust is distinct from local sources of soil parent material. In this study the influence of dust accretion on soil geochemistry is quantified for two different soils from the San Juan Mountains of southwestern Colorado, USA. At both study sites, dust is enriched in several trace elements relative to local rock, especially Cd, Cu, Pb, and Zn. Mass-balance calculations that do not explicitly account for dust inputs indicate the accumulation of some elements in soil beyond what can be explained by weathering of local rock. Most observed elemental enrichments are explained by accounting for the long-term accretion of dust, based on modern isotopic and geochemical estimates. One notable exception is Pb, which based on mass-balance calculations and isotopic measurements may have an additional source at one of the study sites. These results suggest that dust is a major factor influencing the development of soil in these settings and is also an important control of soil weathering fluxes. After accounting for dust inputs in mass-balance calculations, Si weathering fluxes from San Juan Mountain soils are within the range observed for other temperate systems. Comparing dust inputs with mass-balanced based flux estimates suggests dust could account for as much as 50–80% of total long-term chemical weathering fluxes. These results support the notion that dust inputs may sustain chemical weathering fluxes even in relatively young continental settings. Given the widespread input of far-traveled dust, the weathering of dust is likely and important and underappreciated aspect of the global weathering engine.

Aeolian controls of soil geochemistry and weathering fluxes in high-elevation ecosystems of the Rocky Mountains, Colorado

NASA Astrophysics Data System (ADS)

Lawrence, Corey R.; Reynolds, Richard L.; Ketterer, Michael E.; Neff, Jason C.

2013-04-01

When dust inputs are large or have persisted for long periods of time, the signature of dust additions are often apparent in soils. The of dust will be greatest where the geochemical composition of dust is distinct from local sources of soil parent material. In this study the influence of dust accretion on soil geochemistry is quantified for two different soils from the San Juan Mountains of southwestern Colorado, USA. At both study sites, dust is enriched in several trace elements relative to local rock, especially Cd, Cu, Pb, and Zn. Mass-balance calculations that do not explicitly account for dust inputs indicate the accumulation of some elements in soil beyond what can be explained by weathering of local rock. Most observed elemental enrichments are explained by accounting for the long-term accretion of dust, based on modern isotopic and geochemical estimates. One notable exception is Pb, which based on mass-balance calculations and isotopic measurements may have an additional source at one of the study sites. These results suggest that dust is a major factor influencing the development of soil in these settings and is also an important control of soil weathering fluxes. After accounting for dust inputs in mass-balance calculations, Si weathering fluxes from San Juan Mountain soils are within the range observed for other temperate systems. Comparing dust inputs with mass-balanced based flux estimates suggests dust could account for as much as 50-80% of total long-term chemical weathering fluxes. These results support the notion that dust inputs may sustain chemical weathering fluxes even in relatively young continental settings. Given the widespread input of far-traveled dust, the weathering of dust is likely and important and underappreciated aspect of the global weathering engine.

Characterization of airborne float coal dust emitted during continuous mining, longwall mining and belt transport

PubMed Central

Shahan, M.R.; Seaman, C.E.; Beck, T.W.; Colinet, J.F.; Mischler, S.E.

2017-01-01

Float coal dust is produced by various mining methods, carried by ventilating air and deposited on the floor, roof and ribs of mine airways. If deposited, float dust is re-entrained during a methane explosion. Without sufficient inert rock dust quantities, this float coal dust can propagate an explosion throughout mining entries. Consequently, controlling float coal dust is of critical interest to mining operations. Rock dusting, which is the adding of inert material to airway surfaces, is the main control technique currently used by the coal mining industry to reduce the float coal dust explosion hazard. To assist the industry in reducing this hazard, the Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health initiated a project to investigate methods and technologies to reduce float coal dust in underground coal mines through prevention, capture and suppression prior to deposition. Field characterization studies were performed to determine quantitatively the sources, types and amounts of dust produced during various coal mining processes. The operations chosen for study were a continuous miner section, a longwall section and a coal-handling facility. For each of these operations, the primary dust sources were confirmed to be the continuous mining machine, longwall shearer and conveyor belt transfer points, respectively. Respirable and total airborne float dust samples were collected and analyzed for each operation, and the ratio of total airborne float coal dust to respirable dust was calculated. During the continuous mining process, the ratio of total airborne float coal dust to respirable dust ranged from 10.3 to 13.8. The ratios measured on the longwall face were between 18.5 and 21.5. The total airborne float coal dust to respirable dust ratio observed during belt transport ranged between 7.5 and 21.8. PMID:28936001

Effects of inhaled fine dust on lung tissue changes and antibody response induced by spores of opportunistic fungi in goats.

PubMed

Purdy, Charles W; Layton, Robert C; Straus, David C; Ayers, J R

2008-04-01

To investigate the effects of sterile fine dust aerosol inhalation on antibody responses and lung tissue changes induced by Mucor ramosissimus or Trichoderma viride spores following intratracheal inoculation in goats. 36 weanling Boer-Spanish goats. 6 goats were allocated to each of 2 M ramosissimus-inoculated groups, 2 T viride-inoculated groups, and 2 control (tent or pen) groups. One of each pair of sporetreated groups and the tent control group were exposed 7 times to sterilized fine feedyard dust (mean+/-SD particle diameter, <7.72+/-0.69 microm) for 4 hours in a specially constructed tent. Goats in the 4 fungal treatment groups were inoculated intratracheally 5 times with a fungal spore preparation (30 mL), whereas tent control goats were intratracheally inoculated with physiologic saline (0.9% NaCl) solution (30 mL). Pen control goats were not inoculated or exposed to dust. Goats received an IV challenge with equine RBCs to assess antibody responses to foreign antigens. Postmortem examinations were performed at study completion (day 68) to evaluate lung tissue lesions. 5 of 7 deaths occurred between days 18 and 45 and were attributed to fine dust exposures prior to fungal treatments. Fine dust inhalation induced similar lung lesions and precipitating antibodies among spore-treated goats. Following spore inoculations, dust-exposed goats had significantly more spores per gram of consolidated lung tissue than did their nonexposed counterparts. Fine dust inhalation appeared to decrease the ability of goats to successfully clear fungal spores from the lungs following intratracheal inoculation.

Symptoms, airway responsiveness, and exposure to dust in beech and oak wood workers

PubMed Central

Bohadana, A.; Massin, N.; Wild, P.; Toamain, J.; Engel, S.; Goutet, P.

2000-01-01

OBJECTIVES—To investigate the relation between levels of cumulative exposure to wood dust and respiratory symptoms and the occurrence of bronchial hyperresponsiveness among beech and oak workers.
METHODS—114 Male woodworkers from five furniture factories and 13 male unexposed controls were examined. The unexposed control group was supplemented by 200 male historical controls. Statistical analyses were performed excluding and including the historical controls. Dust concentration was measured by personal sampling methods. Cumulative exposure to dust was calculated for each woodworker by multiplying the duration of the work by the intensity of exposure (years.mg/m3). Bronchial hyperresponsiveness was assessed by the methacholine bronchial challenge test. Subjects were labelled methacholine bronchial challenge positive if forced expiratory volume in 1 second (FEV1) fell by ⩾20%. The linear dose-response slope was calculated as the last dose divided by the total dose given.
RESULTS—443 Dust samples were collected. The median cumulative exposure to dust was 110 years.mg/m3 with lower and upper quartiles at 70 and 160 years.mg/m3 Overall, no declines in FEV1 and forced vital capacity (FVC) were found with increasing exposures. A dose-response relation was found between intensity of exposure on the one hand, and sore throat, increased prevalence of positive methacholine bronchial challenge tests, and steeper dose-response slope, on the other.
CONCLUSION—Exposure to oak and beech dust may lead to the development of sore throat and bronchial hyperresponsiveness.


Keywords: bronchial hyperresponsiveness; wood dust; beech; oak PMID:10810114

Potential health benefits of controlling dust emissions in Beijing.

PubMed

Meng, Jing; Liu, Junfeng; Fan, Songmiao; Kang, Chuyun; Yi, Kan; Cheng, Yanli; Shen, Xing; Tao, Shu

2016-06-01

Although the adverse impact of fine particulate matter (i.e., PM2.5) on human health has been well acknowledged, little is known of the health effects of its specific constituents. Over the past decade, the annual average dust concentrations in Beijing were approximately ∼14 μg m(-3), a value that poses a great threat to the city's 20 million residents. In this study, we quantify the potential long-term health damages in Beijing resulting from the dust exposure that occurred from 2000 to 2011. Each year in Beijing, nearly 4000 (95% CI: 1000-7000) premature deaths may be associated with long-term dust exposure, and ∼20% of these deaths are attributed to lung cancer. A decomposition analysis of the inter-annual variability of premature deaths in Beijing indicates that dust concentrations determine the year-to-year tendency, whereas population growth and lung cancer mortality rates drive the increasing tendency of premature death. We suggest that if Beijing takes effective measures towards reducing dust concentrations (e.g., controlling the resuspension of road dust and the fugitive dust from construction sites) to a level comparable to that of New York City's, the associated premature deaths will be significantly reduced. This recommendation offers "low-hanging fruit" suggestions for pollution control that would greatly benefit the public health in Beijing. Copyright © 2016 Elsevier Ltd. All rights reserved.

30 CFR 74.6 - Quality control.

Code of Federal Regulations, 2010 CFR

2010-07-01

... DUST SAMPLING DEVICES Approval Requirements for Coal Mine Dust Personal Sampler Unit § 74.6 Quality... equipment procedures and records and to interview the employees who conduct the control tests. Two copies of...

Field-testing a new directional passive air sampler for fugitive dust in a complex industrial source environment.

PubMed

Ferranti, E J S; Fryer, M; Sweetman, A J; Garcia, M A Solera; Timmis, R J

2014-01-01

Quantifying the sources of fugitive dusts on complex industrial sites is essential for regulation and effective dust management. This study applied two recently-patented Directional Passive Air Samplers (DPAS) to measure the fugitive dust contribution from a Metal Recovery Plant (MRP) located on the periphery of a major steelworks site. The DPAS can collect separate samples for winds from different directions (12 × 30° sectors), and the collected dust may be quantified using several different measurement methods. The DPASs were located up and down-prevailing-wind of the MRP processing area to (i) identify and measure the contribution made by the MRP processing operation; (ii) monitor this contribution during the processing of a particularly dusty material; and (iii) detect any changes to this contribution following new dust-control measures. Sampling took place over a 12-month period and the amount of dust was quantified using photographic, magnetic and mass-loading measurement methods. The DPASs are able to effectively resolve the incoming dust signal from the wider steelworks complex, and also different sources of fugitive dust from the MRP processing area. There was no confirmable increase in the dust contribution from the MRP during the processing of a particularly dusty material, but dust levels significantly reduced following the introduction of new dust-control measures. This research was undertaken in a regulatory context, and the results provide a unique evidence-base for current and future operational or regulatory decisions.

Migration of tungsten dust in tokamaks: role of dust-wall collisions

NASA Astrophysics Data System (ADS)

Ratynskaia, S.; Vignitchouk, L.; Tolias, P.; Bykov, I.; Bergsåker, H.; Litnovsky, A.; den Harder, N.; Lazzaro, E.

2013-12-01

The modelling of a controlled tungsten dust injection experiment in TEXTOR by the dust dynamics code MIGRAINe is reported. The code, in addition to the standard dust-plasma interaction processes, also encompasses major mechanical aspects of dust-surface collisions. The use of analytical expressions for the restitution coefficients as functions of the dust radius and impact velocity allows us to account for the sticking and rebound phenomena that define which parts of the dust size distribution can migrate efficiently. The experiment provided unambiguous evidence of long-distance dust migration; artificially introduced tungsten dust particles were collected 120° toroidally away from the injection point, but also a selectivity in the permissible size of transported grains was observed. The main experimental results are reproduced by modelling.

SPARCLE: Electrostatic Tool for Lunar Dust Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, P. E.; Curtis, S. A.; Minetto, F.

2009-03-16

Successful exploration of most planetary surfaces, with their impact-generated dusty regoliths, will depend on the capabilities to keep surfaces free of the dust which could compromise performance and to collect dust for characterization. Solving the dust problem is essential before we return to the Moon. During the Apollo missions, the discovery was made that regolith fines, or dust, behaved like abrasive velcro, coating surfaces, clogging mechanisms, and making movement progressively more difficult as it was mechanically stirred up during surface operations, and abrading surfaces, including spacesuits, when attempts were made to remove it manually. In addition, some of the astronautsmore » experienced breathing difficulties when exposed to dust that got into the crew compartment. The successful strategy will deal with dust dynamics resulting from interaction between mechanical and electrostatic forces. Here we will describe the surface properties of dust particles, the basis for their behavior, and an electrostatically-based approach and methodology for addressing this issue confirmed by our preliminary results. Our device concept utilizes a focused electron beam to control the electrostatic potential of the surface. A plate of the opposite potential is then used to induce dust migration in the presence of an electrical field. Our goal is a compact device of <5 kg mass and using <5 watts of power to be operational in <5 years with heritage from ionic sweepers for active spacecraft potential control (e.g., on POLAR). Rovers could be fitted with devices that could harness the removal of dust for sampling as part of the extended exploration process on Mercury, Mars, asteroids or outer solar system satellites, as well as the Moon.« less

30 CFR 56.9315 - Dust control.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Loading, Hauling, and Dumping Safety... control. Dust shall be controlled at muck piles, material transfer points, crushers, and on haulage roads...

Controlling dust from concrete saw cutting.

PubMed

Shepherd, Susan; Woskie, Susan

2013-01-01

Cutting concrete with gas-powered saws is ubiquitous in the construction industry and a source of exposure to respirable crystalline silica. Volunteers from the New England Laborers Training Center were recruited to participate in a field experiment examining dust reductions through the use of water, from a hose and from a sprayer, as a dust control. In four series of tests, reinforced concrete pipe was cut under both "dry" and "wet" control conditions. Overall, the geometric mean respirable dust concentration for "dry" cutting (14.396 mg/m³) exceeded both types of water-based controls by more than tenfold. Wet cutting reduced the respirable dust concentration by 85% compared with dry cutting when comparing tests paired by person and saw blade (n = 79 pairs). Using a respirable cyclone, a total of 178 samples were taken. Due to the high variability in dust exposure found in this and other studies of saw cutting, the data were examined for potential exposure determinants that contribute to that variability. Using mixed models, three fixed effects were statistically significant: control condition, worker experience, and location. A random effect for subject was included in the model to account for repeated measures. When each of the significant fixed effects was included with the random effect, it was apparent that inclusion of worker experience or location reduced the between-worker component of exposure variability, while inclusion of control condition (wet vs. dry) explained a large portion of the within-subject variability. Overall, the fixed effect variable for control condition explained the largest fraction of the total exposure variability.

GRAMS: A Grid of RSG and AGB Models

NASA Astrophysics Data System (ADS)

Srinivasan, S.; Sargent, B. A.; Meixner, M.

2011-09-01

We present a grid of oxygen- and carbon-rich circumstellar dust radiative transfer models for asymptotic giant branch (AGB) and red supergiant (RSG) stars. The grid samples a large region of the relevant parameter space, and it allows for a quick calculation of bolometric fluxes and dust mass-loss rates from multi-wavelength photometry. This method of fitting observed spectral energy distributions (SEDs) is preferred over detailed radiative transfer calculations, especially for large data sets such as the SAGE (Surveying the Agents of a Galaxy's Evolution) survey of the Magellanic Clouds. The mass-loss rates calculated for SAGE data will allow us to quantify the dust returned to the interstellar medium (ISM) by the entire AGB population. The total injection rate provides an important constraint for models of galactic chemical evolution. Here, we discuss our carbon star models and compare the results to SAGE observations in the Large Magellanic Cloud (LMC).

ELISA measurement of stachylysin in serum to quantify human exposures to the indoor mold Stachybotrys chartarum.

PubMed

Van Emon, Jeanette M; Reed, Allan W; Yike, Iwona; Vesper, Stephen J

2003-06-01

The goal of this research was to develop a measurable indicator of human exposure to Stachyborys chartarum. Antibodies were produced against the hemolytic agent stachylysin obtained from the mold S. chartarum. These antibodies were used to develop two enzyme-linked immunosorbent assay methods for the analysis of stachylysin in human and rat sera and environmental samples. Stachylysin was measured in rat pups that received nasal instillations of S. chartarum conidia but not in control rat serum. Stachylysin in the serum of five human adults exposed to S. chartarum in water-damaged environments was 371 ng/mL but none was detected in the control serum. Stachylysin was also quantified in spore, wallboard, mycelial, and dust samples. The measurement of stachylysin may be a useful indicator in assessing human exposure to S. chartarum and in determining the presence of this indoor mold.

KEEPING DUST UNDER THE CARPET

EPA Science Inventory

The paper gives results of a study of civil engineering fabrics applied to fugitive dust problems. The fabrics, commonly used for ground stabilization, subsurface drainage, railroad construction and maintenance, sediment control, and erosion control, are available from Celanese, ...

Dust exposure and chronic respiratory symptoms among coffee curing workers in Kilimanjaro: a cross sectional study.

PubMed

Sakwari, Gloria; Bråtveit, Magne; Mamuya, Simon H D; Moen, Bente E

2011-11-24

Coffee processing causes organic dust exposure which may lead to development of respiratory symptoms. Previous studies have mainly focused on workers involved in roasting coffee in importing countries. This study was carried out to determine total dust exposure and respiratory health of workers in Tanzanian primary coffee-processing factories. A cross sectional study was conducted among 79 workers in two coffee factories, and among 73 control workers in a beverage factory. Personal samples of total dust (n = 45 from the coffee factories and n = 19 from the control factory) were collected throughout the working shift from the breathing zone of the workers. A questionnaire with modified questions from the American Thoracic Society questionnaire was used to assess chronic respiratory symptoms. Differences between groups were tested by using independent t-tests and Chi square tests. Poisson Regression Model was used to estimate prevalence ratio, adjusting for age, smoking, presence of previous lung diseases and years worked in dusty factories. All participants were male. The coffee workers had a mean age of 40 years and were older than the controls (31 years). Personal total dust exposure in the coffee factories were significantly higher than in the control factory (geometric mean (GM) 1.23 mg/m3, geometric standard deviation (GSD) (0.8) vs. 0.21(2.4) mg/m3). Coffee workers had significantly higher prevalence than controls for cough with sputum (23% vs. 10%; Prevalence ratio (PR); 2.5, 95% CI 1.0-5.9) and chest tightness (27% vs. 13%; PR; 2.4, 95% CI 1.1-5.2). The prevalence of morning cough, cough with and without sputum for 4 days or more in a week was also higher among coffee workers than among controls. However, these differences were not statistically significant. Workers exposed to coffee dust reported more respiratory symptoms than did the controls. This might relate to their exposure to coffee dust. Interventions for reduction of dust levels and provision of respiratory protective equipment are recommended.

Dust exposure and chronic respiratory symptoms among coffee curing workers in Kilimanjaro: a cross sectional study

PubMed Central

2011-01-01

Background Coffee processing causes organic dust exposure which may lead to development of respiratory symptoms. Previous studies have mainly focused on workers involved in roasting coffee in importing countries. This study was carried out to determine total dust exposure and respiratory health of workers in Tanzanian primary coffee-processing factories. Methods A cross sectional study was conducted among 79 workers in two coffee factories, and among 73 control workers in a beverage factory. Personal samples of total dust (n = 45 from the coffee factories and n = 19 from the control factory) were collected throughout the working shift from the breathing zone of the workers. A questionnaire with modified questions from the American Thoracic Society questionnaire was used to assess chronic respiratory symptoms. Differences between groups were tested by using independent t-tests and Chi square tests. Poisson Regression Model was used to estimate prevalence ratio, adjusting for age, smoking, presence of previous lung diseases and years worked in dusty factories. Results All participants were male. The coffee workers had a mean age of 40 years and were older than the controls (31 years). Personal total dust exposure in the coffee factories were significantly higher than in the control factory (geometric mean (GM) 1.23 mg/m3, geometric standard deviation (GSD) (0.8) vs. 0.21(2.4) mg/m3). Coffee workers had significantly higher prevalence than controls for cough with sputum (23% vs. 10%; Prevalence ratio (PR); 2.5, 95% CI 1.0 - 5.9) and chest tightness (27% vs. 13%; PR; 2.4, 95% CI 1.1 - 5.2). The prevalence of morning cough, cough with and without sputum for 4 days or more in a week was also higher among coffee workers than among controls. However, these differences were not statistically significant. Conclusion Workers exposed to coffee dust reported more respiratory symptoms than did the controls. This might relate to their exposure to coffee dust. Interventions for reduction of dust levels and provision of respiratory protective equipment are recommended. PMID:22114929

A Three-Year Course of House Dust Mite Sublingual Immunotherapy Appears Effective in Controlling the Symptoms of Allergic Rhinitis.

PubMed

Novakova, Silviya M; Novakova, Plamena I; Yakovliev, Plamen H; Staevska, Maria T; Mateva, Nonka G; Dimcheva, Teodora D; Peichev, Jivko L

2018-05-01

Background Allergic rhinitis is the most common allergic disorder. Although the management of the disease is successful in many patients, based on guidelines, some of them remain with symptoms uncontrolled with pharmacotherapy. Presently, there is no substantiated information on the control of allergic rhinitis in patients who underwent sublingual immunotherapy. Objective The purpose of this prospective follow-up study was to assess the control of allergic rhinitis in adults after a three-year course of house dust mite sublingual immunotherapy. Methods This prospective real-life study was designed to include adults with moderate to severe allergic rhinitis sensitized to house dust mite who underwent a three-year course of sublingual immunotherapy. Control of symptoms was assessed by Rhinitis Control Assessment Test (RCAT) after three years of house dust mite sublingual immunotherapy. Additionally, patients assessed their symptoms by utilizing a visual analog scale. Results A total number of 86 consecutively enrolled patients (46 (53.49%) men; mean age 26.10 years (SD = 5.85)) with moderate to severe allergic rhinitis and clinically relevant sensitization to house dust mite were evaluated. When assessed by RCAT on the third year, 74 (86.05%) had well-controlled symptoms and 20 (27.03%) of them were completely controlled. A significant reduction in visual analog scale scores-from 7.52 cm at baseline to 2.31 cm-was established ( P < 0.0001). There was a strong negative correlation between RCAT scores and visual analog scale (r = -0.65; P < 0.01). Conclusion This study provided evidence that a three-year course of house dust mite sublingual immunotherapy appears effective in controlling the symptoms of allergic rhinitis.

Relationship between chicken cellular immunity and endotoxin levels in dust from chicken housing environments

PubMed Central

Roque, Katharine; Shin, Kyung-Min; Jo, Ji-Hoon; Kim, Hyoung-Ah

2015-01-01

Hazardous biochemical agents in animal husbandry indoor environments are known to promote the occurrence of various illnesses among workers and animals. The relationship between endotoxin levels in dust collected from chicken farms and various immunological markers was investigated. Peripheral blood was obtained from 20 broiler chickens and 20 laying hens from four different chicken farms in Korea. Concentrations of total or respirable dust in the inside the chicken farm buildings were measured using a polyvinyl chloride membrane filter and mini volume sampler. Endotoxin levels in the dust were determined by the Limulus Amebocyte Lysate Kinetic method. Interferon-γ production by peripheral blood mononuclear cells stimulated with concanavalin A was significantly lower in broilers or layers from the farms with higher endotoxin concentrations than the chickens from the farms with lower endotoxin levels. An opposite pattern was observed for plasma cortisol concentrations with higher cortisol levels found in chickens from the farms with higher endotoxin levels. When peripheral lymphocytes were examined, the percentage of CD3-Ia+ B cells was lower in layers from farms with higher endotoxin levels than those from locations with lower endotoxin levels. Overall, these results suggest a probable negative association between dust endotoxin levels and cell-mediated immunity in chickens. PMID:25549222

Swine confinement buildings: effects of airborne particles and settled dust on airway smooth muscles.

PubMed

Demanche, Annick; Bonlokke, Jakob; Beaulieu, Marie-Josee; Assayag, Evelyne; Cormier, Yvon

2009-01-01

Swine confinement workers are exposed to various contaminants. These agents can cause airway inflammation and bronchoconstriction. This study was undertaken to evaluate if the bronchoconstrictive effects of swine barn air and settled dust are mediated by endotoxin, and if these effects are directly mediated on airway smooth muscles. Mouse tracheas where isolated and mounted isometrically in organ baths. Tracheas, with or without epithelium, were attached to a force transducer and tension was recorded. Concentrated swine building air at 68 EU/ml or settled dust extract at 0.01 g/ml were added for 20 minutes and tracheal smooth muscle contraction was measured. Direct role of LPS was assessed by removing it from air concentrates with an endotoxin affinity resin. Swine barn air and settled dust extract caused contraction of tracheal smooth muscle by 26 and 20%, respectively, of the maximal induced by methacholine. Removal of epithelium did not affect the contractile effects. LPS alone and LPS with peptidoglycans did not induce contraction. However, when endotoxin was removed from swine barn air concentrates, it lost 24% of its contractile effect. Concentrated swine barn air and settled dust have direct effects on airway smooth muscles. This effect is partially due to LPS but a synergy with other components of the environment of swine confinement buildings is required.

Polycyclic Aromatic Hydrocarbons in Residential Dust and Risk of Childhood Acute Lymphoblastic Leukemia

PubMed Central

Deziel, NC; Rull, RP; Colt, JS; Reynolds, P; Whitehead, TP; Gunier, RB; Month, SR; Taggart, DR; Buffler, P; Ward, MH; Metayer, C

2014-01-01

Several polycyclic aromatic hydrocarbons (PAHs) are known or probable human carcinogens. We evaluated the relationship between PAH exposure and risk of childhood acute lymphoblastic leukemia (ALL) using concentrations in residential dust as an exposure indicator. We conducted a population-based case-control study (251 ALL cases, 306 birth-certificate controls) in Northern and Central California from 2001–2007. We collected residential dust using a high volume small surface sampler (HVS3) (n=185 cases, 212 controls) or by sampling from participants’ household vacuum cleaners (n=66 cases, 94 controls). We evaluated log-transformed concentrations of 9 individual PAHs, the summed PAHs, and the summed PAHs weighted by their carcinogenic potency (the toxic equivalence). We calculated odds ratios (ORs) and 95% confidence intervals (CI) using logistic regression adjusting for demographic characteristics and duration between diagnosis/reference date and dust collection. Among participants with HVS3 dust, risk of ALL was not associated with increasing concentration of any PAHs (based on OR per ln(ng/g). Among participants with vacuum dust, we observed positive associations between ALL risk and increasing concentrations of benzo[a]pyrene (OR per ln[ng/g]=1.42, 95% CI=0.95, 2.12), dibenzo[a,h]anthracene (OR=1.98, 95% CI=1.11, 3.55), benzo[k]fluoranthene (OR=1.71, 95% CI= 0.91, 3.22), indeno[1,2,3-cd]pyrene (OR=1.81, 95% CI=1.04, 3.16), and the toxic equivalence (OR=2.35, 95% CI=1.18, 4.69). The increased ALL risk among participants with vacuum dust suggests that PAH exposure may increase the risk of childhood ALL; however, reasons for the different results based on HVS3 dust samples deserve further study. PMID:24948546

Particle Removal by Electrostatic and Dielectrophoretic Forces for Dust Control During Lunar Exploration Missions

NASA Technical Reports Server (NTRS)

Calle, C. I.; Buhler, C. R.; McFall, J. L.; Snyder, S. J.

2009-01-01

Particle removal during lunar exploration activities is of prime importance for the success of robotic and human exploration of the moon. We report on our efforts to use electrostatic and dielectrophoretic forces to develop a dust removal technology that prevents the accumulation of dust on solar panels and removes dust adhering to those surfaces. Testing of several prototypes showed solar shield output above 90% of the initial potentials after dust clearing.

Dust control effectiveness of drywall sanding tools.

PubMed

Young-Corbett, Deborah E; Nussbaum, Maury A

2009-07-01

In this laboratory study, four drywall sanding tools were evaluated in terms of dust generation rates in the respirable and thoracic size classes. In a repeated measures study design, 16 participants performed simulated drywall finishing tasks with each of four tools: (1) ventilated sander, (2) pole sander, (3) block sander, and (4) wet sponge. Dependent variables of interest were thoracic and respirable breathing zone dust concentrations. Analysis by Friedman's Test revealed that the ventilated drywall sanding tool produced significantly less dust, of both size classes, than did the other three tools. The pole and wet sanders produced significantly less dust of both size classes than did the block sander. The block sander, the most commonly used tool in drywall finishing operations, produced significantly more dust of both size classes than did the other three tools. When compared with the block sander, the other tools offer substantial dust reduction. The ventilated tool reduced respirable concentrations by 88% and thoracic concentrations by 85%. The pole sander reduced respirable concentrations by 58% and thoracic by 50%. The wet sander produced reductions of 60% and 47% in the respirable and thoracic classes, respectively. Wet sponge sanders and pole sanders are effective at reducing breathing-zone dust concentrations; however, based on its superior dust control effectiveness, the ventilated sander is the recommended tool for drywall finishing operations.

Global Gene Expression Profiling in Lung Tissues of Rat Exposed to Lunar Dust Particles

NASA Technical Reports Server (NTRS)

Yeshitla, Samrawit A.; Lam, Chiu-Wing; Kidane, Yared H.; Feiveson, Alan H.; Ploutz-Snyder, Robert; Wu, Honglu; James, John T.; Meyers, Valerie E.; Zhang, Ye

2014-01-01

The Moon's surface is covered by a layer of fine, potential reactive dust. Lunar dust contain about 1-2% respirable very fine dust (less than 3 micrometers). The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to analyze the dynamics of global gene expression changes in lung tissues of rats exposed to lunar dust particles. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose-only inhalation chambers to concentrations of 0 (control air), 2.1, 6.8, 21, and 61 mg/m3 of lunar dust. Animals were euthanized at 1 day and 13 weeks after the last inhalation exposure. After being lavaged, lung tissue from each animal was collected and total RNA was isolated. Four samples of each dose group were analyzed using Agilent Rat GE v3 microarray to profile global gene expression of 44K transcripts. After background subtraction, normalization, and log transformation, t tests were used to compare the mean expression levels of each exposed group to the control group. Correction for multiple testing was made using the method of Benjamini, Krieger, and Yekuteli (1) to control the false discovery rate. Genes with significant changes of at least 1.75 fold were identified as genes of interest. Both low and high doses of lunar dust caused dramatic, dose-dependent global gene expression changes in the lung tissues. However, the responses of lung tissue to low dose lunar dust are distinguished from those of high doses, especially those associated with 61mg/m3 dust exposure. The data were further integrated into the Ingenuity system to analyze the gene ontology (GO), pathway distribution and putative upstream regulators and gene targets. Multiple pathways, functions, and upstream regulators have been identified in response to lunar dust induced damage in the lung tissue.

Review of dust transport and mitigation technologies in lunar and Martian atmospheres

NASA Astrophysics Data System (ADS)

Afshar-Mohajer, Nima; Wu, Chang-Yu; Curtis, Jennifer Sinclair; Gaier, James R.

2015-09-01

Dust resuspension and deposition is a ubiquitous phenomenon in all lunar and Martian missions. The near-term plans to return to the Moon as a stepping stone to further exploration of Mars and beyond bring scientists' attention to development and evaluation of lunar and Martian dust mitigation technologies. In this paper, different lunar and Martian dust transport mechanisms are presented, followed by a review of previously developed dust mitigation technologies including fluidal, mechanical, electrical and passive self-cleaning methods for lunar/Martian installed surfaces along with filtration for dust control inside cabins. Key factors in choosing the most effective dust mitigation technology are recognized to be the dust transport mechanism, energy consumption, environment, type of surface materials, area of the surface and surface functionality. While electrical methods operating at higher voltages are identified to be suitable for small but light sensitive surfaces, pre-treatment of the surface is effective for cleaning thermal control surfaces, and mechanical methods are appropriate for surfaces with no concerns of light blockage, surface abrasion and 100% cleaning efficiency. Findings from this paper can help choose proper surface protection/cleaning for future space explorations. Hybrid techniques combining the advantages of different methods are recommended.

CROSS REACTIVITY IN ALLERGIC ASTHMA-LIKE RESPONSES BETWEEN MOLD AND HOUSE DUST MITE IN MICE

EPA Science Inventory

Molds are ubiquitous in the environment and exposures to molds contribute to various human diseases including allergic asthma. Some mold allergens have been implicated as the causal agent for allergic asthma. Western blot analysis demonstrated IgE-binding cross-reactivity among m...

Managing Indoor Air Quality in Schools.

ERIC Educational Resources Information Center

Woolums, Jennifer

This publication examines the causes and effects of poor indoor air quality and provides information for reducing exposure to indoor contaminants in schools. It discusses the various indoor pollutants found in schools, including dust, chemical agents, gases, and volatile organic compounds; where they are found in schools; and their health effects…

30 CFR 74.6 - Quality control.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Quality control. 74.6 Section 74.6 Mineral... of the CMDPSU will be maintained in production through adequate quality control procedures, MSHA and... DUST SAMPLING DEVICES Approval Requirements for Coal Mine Dust Personal Sampler Unit § 74.6 Quality...

Respiratory Symptoms and Lung Function among Greek Cotton Industry Workers: A Cross-Sectional Study.

PubMed

Anyfantis, Ioannis D; Rachiotis, Georgios; Hadjichristodoulou, Cristos; Gourgoulianis, Konstantinos I

2017-01-01

Workers in cotton industry are occupationally exposed to various dust-related hazards. The nature of these agents and the respective exposure levels depend on the cotton industry specific sector. These exposures could be associated with respiratory symptoms and changes in lung function parameters. To evaluate associations between occupational exposure and respiratory function as well as reported symptoms in several groups of workers at different stages of the cotton industry in a vertical approach that covers all the major sectors-from cotton ginning to weaving and fabric production. A questionnaire on respiratory symptoms and individual as well as workplace characteristics was completed by 256 workers at the cotton industry and 148 office workers (control group). Both groups underwent spirometry. Workers in cotton industry reported a higher prevalence of severe dyspnea (p=0.002) and wheezing (p=0.004) compared to the control group. Also they were found to have a lower predicted FEV 1 % (p<0.029) and lower FEV 1 /FVC (p<0.001) values. In addition, a higher prevalence of FEV 1 % <80% (p<0.001) and FEV 1 /FVC <70% (p=0.041) were found among textile workers. Similar results were found for non-smoker textile workers compared to non-smoker control group workers. Those working in cotton ginning mills recorded the highest decrease of spirometric values. Duration of employment in cotton industry and smoking use were found to be predictors of lung function decline for cotton industry workers. Occupational exposure to cotton dust was associated with increased prevalence of respiratory symptoms and obstructive pattern in pulmonary function test.

Preparation of the Iron Oxide Red from the Converter Dust by the Magnetic Separation and Roasting Process

NASA Astrophysics Data System (ADS)

Guo, Z. J.; Li, S. Q.; Yang, C. Q.

2017-05-01

Preparation of iron oxide red (α-Fe2O3) from the converter dust by the superconductivity high gradient magnetic separation (S-HGMS) and roasting process was investigated in the paper. The basic properties of the dust were studied by the X Ray Fluorescence, the chemical analysis and the X Ray Diffraction methods. The results showed that the raw dust mainly contained elements of Fe‵O‵Si‵Ca, the iron content of the raw dust was 61.80%, and there were ferrous phases of Fe3O4, α-Fe2O3, Fe2(SiO4) and CaFe(Si2O6) in the raw dust. Under the optimum conditions of magnetic field intensity of 1.8T, the dispersion agent of 30mg/L and velocity of 500mL/min, the powders absorbed by the magnetic medium mainly contained Fe3O4 and α-Fe2O3, and the iron content of powders absorbed was up to 65.90%. The Fe2+ content of the powders absorbed under the optimum magnetic conditions dropped to 0.25% from 19.10% after roasting of fifty minutes, and the iron content of powders absorbed under the optimum magnetic conditions fell to 64% due to oxidation, and the Fe3O4 was removed. Finally the α-Fe2O3 content was up to 91.07% in the iron oxide red.

Monitoring the airborne dust and water vapor in the low atmosphere of Mars: the MEDUSA experiment for the ESA ExoMars mission

NASA Astrophysics Data System (ADS)

Esposito, Francesca; Colangeli, Luigi; Palumbo, Pasquale; Della Corte, Vincenzo; Molfese, Cesare; Merrison, Jonathan; Nornberg, Per; Lopez-Moreno, J. J.; Rodriguez Gomez, Julio

Dust and water vapour are fundamental components of Martian atmosphere. Dust amount varies with seasons and with the presence of local and global dust storms, but never drops entirely to zero. Aerosol dust has always played a fundamental role on the Martian climate. Dust interaction with solar and thermal radiation and the related condensation and evaporation processes influence the thermal structure and balance, and the dynamics (in terms of circulation) of the atmosphere. Water vapour is a minor constituent of the Martian atmosphere but it plays a fundamental role and it is important as indicator of seasonal climate changes. Moreover, the interest about the water cycle on local and global scales is linked to the fundamental function that water could have played in relation to the existence of living organisms on Mars. In view of tracing the past environmental conditions on Mars, that possibly favoured the appearing of life forms, it is important to study the present climate and its evolution, on which dust and water vapour have (and have had) strong influence. Moreover, nowadays, dust is a relevant agent that affects environmental conditions in the lower Martian atmosphere and, thus, may interact / interfere with any instrumentation delivered to Mars surface for in situ analyses. So, information on dust properties and deposition rate is also of great interest for future mission design. Knowledge of how much dust settles on solar arrays and the size and shape of particles will be crucial elements for designing missions that will operate by solar power for periods of several years and will have moving parts which will experience degradation by dust. This information is essential also for proper planning of future manned missions in relation to characterisation of environmental hazardous conditions. Little is known about dust structure and dynamics, so far. Size distribution is known only roughly and the mechanism of settling and rising into the atmosphere, the rates and geographic variability are matter of controversy. The instrument MEDUSA (Martian Environmental DUst Systematic Analyser) has been designed to measure directly and quantitatively in situ the cumulative dust mass flux and dust deposition rate, the physical and electrification properties, the size distribution of intercepted particles and the water vapour abundance versus time, a goal that has never been reached so far. MEDUSA has been selected by ESA as one of the environmental instruments to be included in the payload Humboldt of ExoMars lander.

Herschel-ATLAS: Dusty early-type galaxies

NASA Astrophysics Data System (ADS)

Rowlands, K.; Dunne, L.; Maddox, S.

2015-03-01

Early-type galaxies (ETGs) are thought to be devoid of dust and star-formation, having formed most of their stars at early epochs. We present the detection of the dustiest ETGs in a large-area blind submillimetre survey with Herschel (H-ATLAS, Eales et al. 2010), where the lack of pre-selection in other bands makes it the first unbiased survey for cold dust in ETGs. The parent sample of 1087 H-ATLAS galaxies in this study have a >= 5σ detection at 250μm, a reliable optical counterpart to the submillimetre source (Smith et al. 2011) and a spectroscopic redshift from the GAMA survey (Driver et al. 2011). Additionally, we construct a control sample of 1052 optically selected galaxies undetected at 250μm and matched in stellar mass to the H-ATLAS parent sample to eliminate selection effects. ETGs were selected from both samples via visual classifications using SDSS images. Further details can be found in Rowlands et al. (2012). Physical parameters are derived for each galaxy using the multiwavelength spectral energy distribution (SED) fitting code of da Cunha, Charlot and Elbaz (2008), Smith et al. 2012, using an energy balance argument. We investigate the differences between the dusty ETGs and the general ETG population, and find that the H-ATLAS ETGs are more than an order of magnitude dustier than the control ETGs. The mean dust mass of the 42 H-ATLAS ETGs is 5.5 × 107M⊙ (comparable to the dust mass of spirals in our sample), whereas the dust mass of the 233 control ETGs inferred from stacking at optical positions on the 250μm map is (0.8 - 4.0) × 106M⊙ for 25-15 K dust. The average star-formation rate of the H-ATLAS ETGs is 1.0 dex higher than that of control ETGs, and the mean r-band light-weighted age of the H-ATLAS ETGs is 1.8 Gyr younger than the control ETGs. The rest-frame NUV - r colours of the H-ATLAS ETGs are 1.0 magnitudes bluer than the control ETGs, and some ETGs may be transitioning from the blue cloud to the red sequence. Some H-ATLAS ETGs show signs of morphological disturbance and may have undergone recent rejuvenation of their ISM via gas and dust delivered by mergers. It is found that late-type stars cannot produce enough dust to account for that observed in the H-ATLAS ETGs. This indicates that either an external source of dust from mergers is required, a substantial amount of dust grain growth must occur in the ISM, or dust destruction by hot X-ray gas is less efficient than predicted.

The effect of cleanliness control during installation work on the amount of accumulated dust in ducts of new HVAC installations.

PubMed

Holopainen, R; Tuomainen, M; Asikainen, V; Pasanen, P; Säteri, J; Seppänen, O

2002-09-01

The aim of this study was to evaluate the amount of dust in supply air ducts in recently installed ventilation systems. The samples for the determination of dust accumulation were collected from supply air ducts in 18 new buildings that have been constructed according to two different cleanliness control levels classified as category P1 (low oil residues and protected against contaminations) and category P2, as defined in the Classification of Indoor Climate, Construction and Building Materials. In the ducts installed according to the requirements of cleanliness category P1 the mean amount of accumulated dust was 0.9 g/m2 (0.4-2.9 g/m2), and in the ducts installed according to the cleanliness category P2 it was 2.3 g/m2 (1.2-4.9 g/m2). A significant difference was found in the mean amounts of dust between ducts of categories P1 and P2 (P < 0.008). The cleanliness control procedure in category P1 proved to be a useful and effective tool for preventing dust accumulation in new air ducts during the construction process. Additionally, the ducts without residual oil had lower amounts of accumulated dust indicating that the demand for oil free components in the cleanliness classification is reasonable.

Climatic controls of the interannual to decadal variability in Saudi Arabian dust activity: Towards the development of a seasonal prediction tool

NASA Astrophysics Data System (ADS)

Yu, Y.; Notaro, M.; Liu, Z.; Alkolibi, F.; Fadda, E.; Bakhrjy, F.

2013-12-01

Atmospheric dust significantly influences the climate system, as well as human life in Saudi Arabia. Skillful seasonal prediction of dust activity with climatic variables will help prevent some negative social impacts of dust storms. Yet, the climatic regulators on Saudi Arabian dust activity remain largely unaddressed. Remote sensing and station observations show consistent seasonal cycles in Saudi Arabian dust activity, which peaks in spring and summer. The climatic controls on springtime and summertime Saudi Arabian dust activity during 1975-2010 are studied using observational and reanalysis data. Empirical Orthogonal Function (EOF) of the observed Saudi Arabian dust storm frequency shows a dominant homogeneous pattern across the country, which has distinct interannual and decadal variations, as revealed by the power spectrum. Regression and correlation analyses reveal that Saudi Arabian dust activity is largely tied to precipitation on the Arabian Peninsula in spring and northwesterly (Shamal) wind in summer. On the seasonal-interannual time scale, warm El Niño-Southern Oscillation (ENSO) phase (El Niño) in winter-to-spring inhibits spring dust activity by increasing the precipitation over the Rub'al Khali Desert, a major dust source region on the southern Arabian Peninsula; warm ENSO and warm Indian Ocean Basin Mode (IOBM) in winter-to-spring favor less summer dust activity by producing anomalously low sea-level pressure over eastern north Africa and Arabian Peninsula, which leads to the reduced Shamal wind speed. The decadal variation in dust activity is likely associated with the Atlantic Multidecadal Oscillation (AMO), which impacts Sahel rainfall and North African dust, and likely dust transport to Saudi Arabia. The Pacific Decadal Oscillation (PDO) and tropical Indian Ocean SST also have influence on the decadal variation in Saudi Arabian dust activity, by altering precipitation over the Arabian Peninsula and summer Shamal wind speed. Using eastern tropical Pacific SST as the high-frequency predictor and antecedent accumulated precipitation over the Arabian Peninsula and North Africa as low-frequency predictors, the predicted seasonal dust activity over Saudi Arabia is well correlated with the original time series (correlation above 0.6).

The Paleozoic Dust Bowl: Dust Deposition in Tropical Western Pangaea (Midcontinent U.S.) at the Terminus of the Late Paleozoic Ice Age

NASA Astrophysics Data System (ADS)

Soreghan, G. S.; Heavens, N. G.; Benison, K. C.; Soreghan, M. J.; Mahowald, N. M.; Foster, T.; Zambito, J.; Sweet, A.; Kane, M.

2012-12-01

Atmospheric dust is well recognized and studied as both an archive and agent of climate change in Earth's relatively recent past. Archives of past dust include loess deposits and dust recovered from ocean- and ice-cores. Dust remains poorly known in Earth's past prior to the Cenozoic, but is increasingly recognized in the form of paleo-loess deposits, and (epeiric) marine strata that accumulated isolated from fluvio-deltaic influx. Here, we report on the growing recognition of voluminous dust deposits preserved in the Permian record of the U.S. Midcontinent (western tropical Pangaea). Fine-grained redbeds predominate in Permian strata throughout the U.S. Midcontinent, but notably in a swath extending from Oklahoma through South Dakota. These units consist predominantly of red mudstone and siltstone in commonly massive units, but sedimentary structures and bedding that signal aqueous processes (e.g. laminations, ripples) have led most to infer deltaic or tidal deposition. The absence of channel systems to deliver the sediment, as well as the predominantly massive and laterally continuous character and the uniform fine grain size signal wind transport, implying that these units record sustained dust deposition overprinted at times by sub-aqueous deposition in lakes, including ephemeral saline and acid lakes that led to evaporite cementation. Detrital zircon geochronology indicates that much of the dust originated in the relatively distant Appalachian-Ouachita orogenic systems, which formed part of the central Pangaean mountains (CPM), the collisional zone that sutured the supercontinent. Within the Anadarko basin of Oklahoma, Permian redbeds record >2 km of predominantly dust deposition, some of the thickest dust deposits yet documented in Earth's record. Yet the tropical setting is remarkably non-uniformitarian, as much Quaternary loess occurs in mid- to high-latitude regions, commonly linked to glacial genesis. We are currently investigating with both data and modeling possible causes and consequences of this massive dust record, which may include (1) partial glacial genesis in the CPM, (2) the action of the Pangaean mega-monsoon, and (3) particularly effective dust traps in the Midcontinent region. Modeling constrains the erosivity (the effect of winds and soil moisture effects) of a range of possible climate states on dust mobilization and underscores the relative difficulty of sourcing dust directly from the Appalachian-Ouachita orogenic system under most circumstances. Combining data and modeling helps constrain the erodibility (sediment availability, coherence, etc.) of dust sources. Reconstructions of marine dust deposition to the south and the west of the Anadarko basin suggest glacial-interglacial timescale erodibility changes were similar to those seen in the Midcontinent in the last 20,000 years, when it was at a much higher latitude.

Bioaccessibility of Fipronil Sorbed to Soil and House Dust

EPA Science Inventory

Fipronil is a phenylpyrazole insecticide with uses ranging from soil treatment, to the control of household pests and ectoparasites on pets. Soils and house dusts readily sorb fipronil and when these soils and dusts are ingested, the fipronil may become bioaccessible for uptake ...

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: DUST SUPPRESSANT PRODUCTS: NORTH AMERICAN SALT COMPANY'S DUSTGARD

EPA Science Inventory

Dust suppressant products used to control particulate emissions from unpaved roads are among the technologies evaluated by the Air Pollution Control Technology (APCT) Verification Center, part of the U.S. Environmental Protection Agency's Environmental Technology Verification (ET...

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: DUST SUPPRESSANT PRODUCTS: SYNTECH PRODUCTS CORPORATION'S TECHSUPPRESS

EPA Science Inventory

Dust suppressant products used to control particulate emissions from unpaved roads are among the technologies evaluated by the Air Pollution Control Technology (APCT) Verification Center, part of the U.S. Environmental Protection Agency's Environmental Technology Verification (ET...

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: DUST SUPPRESSANT PRODUCTS: SYNTECH PRODUCTS CORPORATION'S PETROTAC

EPA Science Inventory

Dust suppressant products used to control particulate emissions from unpaved roads are among the technologies evaluated by the Air Pollution Control Technology (APCT) Verification Center, part of the U.S. Environmental Protection Agency's Environmental Technology Verification (ET...

Injurious effects of wool and grain dusts on alveolar epithelial cells and macrophages in vitro.

PubMed Central

Brown, D M; Donaldson, K

1991-01-01

Epidemiological studies of workers in wool textile mills have shown a direct relation between the concentration of wool dust in the air and respiratory symptoms. Injurious effects of wool dust on the bronchial epithelium could be important in causing inflammation and irritation. A pulmonary epithelial cell line in vitro was therefore used to study the toxic effects of wool dust. Cells of the A549 epithelial cell line were labelled with 51Cr and treated with whole wool dusts and extracts of wool, after which injury was assessed. Also, the effects of grain dust, which also causes a form of airway obstruction, were studied. The epithelial injury was assessed by measuring 51Cr release from cells as an indication of lysis, and by monitoring cells which had detached from the substratum. No significant injury to A549 cells was caused by culture with any of the dusts collected from the air but surface "ledge" dust caused significant lysis at some doses. Quartz, used as a toxic control dust, caused significant lysis at the highest concentration of 100 micrograms/well. To determine whether any injurious material was soluble the dusts were incubated in saline and extracts collected. No extracts caused significant injury to epithelial cells. A similar lack of toxicity was found when 51Cr labelled control alveolar macrophages were targets for injury. Significant release of radiolabel was evident when macrophages were exposed to quartz at concentrations of 10 and 20 micrograms/well, there being no significant injury with either wool or grain dusts. These data suggest that neither wool nor grain dust produce direct injury to epithelial cells, and further studies are necessary to explain inflammation leading to respiratory symptoms in wool and grain workers. PMID:2015211

Dusting off the epidemiological triad: could it work with obesity?

PubMed

Egger, G; Swinburn, B; Rossner, S

2003-05-01

The search for effective ways of dealing with obesity has centred on biological research and clinical management. However, obesity needs to be conceptualized more broadly if the modern pandemic is to be arrested. The epidemiological triad (hosts, agent/vectors and environments) has served us well in dealing with epidemics in the past, and may be worth re-evaluating to this end. Education, behaviour change and clinical practices deal predominantly with the host, although multidisciplinary practices such as shared-care might also be expected to impact on other corners of the triad. Technology deals best with the agent of obesity (energy imbalance) and it's vectors (excessive energy intake and/or inadequate energy expenditure), and policy and social change are needed to cope with the environment. The value of a broad model like this, rather than specific isolated approaches, is that the key players such as legislators, health professionals, governments and industry can see their roles in attenuating and eventually reversing the epidemic. It also highlights the need to intervene at all levels in obesity control and reduces the relevance of arguments about nature vs. nurture.

Effect of energetic electrons on dust charging in hot cathode filament discharge

NASA Astrophysics Data System (ADS)

Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhyay, M.

2011-03-01

The effect of energetic electrons on dust charging for different types of dust is studied in hydrogen plasma. The hydrogen plasma is produced by hot cathode filament discharge method in a dusty plasma device. A full line cusped magnetic field cage is used to confine the plasma elements. To study the plasma parameters for various discharge conditions, a cylindrical Langmuir probe having 0.15 mm diameter and 10.0 mm length is used. An electronically controlled dust dropper is used to drop the dust particles into the plasma. For different discharge conditions, the dust current is measured using a Faraday cup connected to an electrometer. The effect of secondary emission as well as discharge voltage on charging of dust grains in hydrogen plasma is studied with different dust.

Effect of asthma management education program on stress and compliance of patients with allergic asthma to house dust mite.

PubMed

Yoo, Yang Sook; Cho, Ok Hee; Kim, Eun Sin; Jeong, Hye Sun

2005-06-01

This study was designed to examine the effect of asthma management education program applied to allergic asthma patients receiving immunotherapy due to house dust mite on their stress and compliance with health care regimens. A quasi experimental design with non-equivalent control group and non-synchronized design was used. The subjects of this study were 61 patients who were receiving immunotherapy at intervals of a week after their symptoms were diagnosed as house dust mite allergic asthma at the pulmonary department of a university hospital in Seoul. They were divided into an experimental group of 29 patients who received asthma management education and a control group of 32 patients. The asthma management education program was composed of group education (once) and reinforcement education (three times) with environmental therapy and immunotherapy to house dust mite. Stress significantly decreased in the experimental group compared to that in the control group. Compliance with health care regimens significantly increased in the experimental group compared to that in the control group. The results suggested that the asthma management education program is effective for the management of stress and the improvement of compliance in patients with allergic asthma to house dust mite.

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: DUST SUPPRESSANT PRODUCTS: MIDWEST INDUSTRIAL SUPPLY, INC.'S ENVIROKLEEN

EPA Science Inventory

Dust suppressant products used to control particulate emissions from unpaved roads are among the technologies evaluated by the Air Pollution Control Technology (APCT) Verification Center, part of the U.S. Environmental Protection Agency's Environmental Technology Verification (ET...

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: DUST SUPPRESSANT PRODUCTS: MIDWEST INDUSTRIAL SUPPLY, INC.'S EK35

EPA Science Inventory

Dust suppressant products used to control particulate emissions from unpaved roads are among the technologies evaluated by the Air Pollution Control Technology (APCT) Verification Center, part of the U.S. Environmental Protection Agency's Environmental Technology Verification (ET...

Effect of simulated ambient particulate matter exposure on performance, rectal temperature, and leukocytosis of young Spanish goats with or without tilmicosin phosphate.

PubMed

Chirase, N K; Purdy, C W; Avampato, J M

2004-04-01

Dust is an environmental stressor and can become extensive in agricultural production systems. Thirty-six female, Spanish goats (average BW 21.1 kg, SEM = 1.31; age = 4 mo) were randomly assigned to simulated dust events or no dust, with or without tilmicosin phosphate treatment in a 2 x 2 factorial arrangement of treatments to determine effects on performance, rectal temperature, and leukocyte changes. All goats were fed a standard growing diet (13.6% CP) consisting of 37% roughage and 63% concentrate (DM basis). Feed intake was measured daily, and BW (unshrunk) measured individually every 7 d. The tilmicosin-treated group received tilmicosin phosphate (10 mg/kg BW s.c.) before starting the study. Goats exposed to dust were enclosed as a group inside a canvass tent for 4 h each day and ground feed yard manure dust (mean particle size 100 microm) was aerosolized inside the tent to simulate a dust event. There was one single dust event (Phase I) followed by rectal temperature measurement, and heparinized blood collection for complete cell counts at 0 (pretrial), 4, 12, 20, 44, 68, and 210 h after dust exposure. This was followed by 21 d of chronic dust events (Phase II). The sampling procedures for Phase II were exactly the same as in Phase I, except that samples were obtained daily at 0 (before dust application), 4, 8, and 12 h after each dust event. Dust treatment had no effect (P > 0.05) on feed intake or ADG, but the gain:feed (G:F) ratio was lower (P < 0.05) in the control goats than the dust exposed group. Tilmicosin phosphate-treated goats had a higher (P < 0.05) G:F ratio than untreated goats. Dust exposure increased (P < 0.002), but tilmicosin treatment decreased (P < 0.05) rectal temperature at 4 and 8 h. Dust exposure increased (P < 0.02) blood lymphocyte counts compared with controls. These results suggest that simulated dust events altered rectal temperature and leukocyte counts of goats.

Exposure to ultrafine particles in asphalt work.

PubMed

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

2008-12-01

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

Fugitive dust emission source profiles and assessment of selected control strategies for particulate matter at gravel processing sites in Taiwan.

PubMed

Chang, Chang-Tang; Chang, Yu-Min; Lin, Wen-Yinn; Wu, Ming-Ching

2010-10-01

Particles emitted from gravel processing sites are one contributor to worsening air quality in Taiwan. Major pollution sources at gravel processing sites include gravel and sand piles, unpaved roads, material crushers, and bare ground. This study analyzed fugitive dust emission characteristics at each pollution source using several types of particle samplers, including total suspended particulates (TSP), suspended particulate (PM10), fine suspended particulate (PM2.5), particulate sizer, and dust-fall collectors. Furthermore, silt content and moisture in the gravel were measured to develop particulate emission factors. The results showed that TSP (< 100 microm) concentrations at the boundary of gravel sites ranged from 280 to 1290 microg/m3, which clearly exceeds the Taiwan hourly air quality standard of 500 microg/m3. Moreover, PM10 concentrations, ranging from 135 to 550 microg/m3, were also above the daily air quality standard of 125 microg/m3 and approximately 1.2 and 1.5 times the PM2.5 concentrations, ranging from 105 to 470 microg/m3. The size distribution analysis reveals that mass mean diameter and geometric standard deviation ranged from 3.2 to 5.7 microm and from 2.82 to 5.51, respectively. In this study, spraying surfactant was the most effective control strategy to abate windblown dust from unpaved roads, having a control efficiency of approximately 93%, which is significantly higher than using paved road strategies with a control efficiency of approximately 45%. For paved roads, wet suppression provided the best dust control efficiencies ranging from 50 to 83%. Re-vegetation of disturbed ground had dust control efficiencies ranging from 48 to 64%.

Silica dust exposures during selected construction activities.

PubMed

Flanagan, Mary Ellen; Seixas, Noah; Majar, Maria; Camp, Janice; Morgan, Michael

2003-01-01

This study characterized exposure for dust-producing construction tasks. Eight common construction tasks were evaluated for quartz and respirable dust exposure by collecting 113 personal task period samples for cleanup; demolition with handheld tools; concrete cutting; concrete mixing; tuck-point grinding; surface grinding; sacking and patching concrete; and concrete floor sanding using both time-integrating filter samples and direct-reading respirable dust monitors. The geometric mean quartz concentration was 0.10 mg/m(3) (geometric standard deviation [GSD]=4.88) for all run time samples, with 71% exceeding the threshold limit value. Activities with the highest exposures were surface grinding, tuck-point grinding, and concrete demolition (GM[GSD] of 0.63[4.12], 0.22[1.94], and 0.10[2.60], respectively). Factors recorded each minute were task, tool, work area, respiratory protection and controls used, estimated cross draft, and whether anyone nearby was making dust. Factors important to exposure included tool used, work area configuration, controls employed, cross draft, and in some cases nearby dust. More protective respirators were employed as quartz concentration increased, although respiratory protection was found to be inadequate for 42% of exposures. Controls were employed for only 12% of samples. Exposures were reduced with three controls: box fan for surface grinding and floor sanding, and vacuum/shroud for surface grinding, with reductions of 57, 50, and 71%, respectively. Exposures were higher for sweeping compound, box fan for cleanup, ducted fan dilution, and wetted substrate. Construction masons and laborers are frequently overexposed to silica. The usual protection method, respirators, was not always adequate, and engineering control use was infrequent and often ineffective.

Studies on aerosols. I. Reduction of dust deposition in lungs of rabbits by aqueous aerosols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dautrebande, L.; Highman, B.; Alford, W.C.

1948-01-01

Rabbits were exposed to air containing 0.01 to 0.04 mg/liter zinc silicate dust with a mean diameter of 0.9 ..mu..m. Irregular breathing with some cyanosis after 2 hr was observed. Pulmonary changes after 4.5 to 5 hr included bronchitis, patchy atelectasis, emphysema, interstitial pneumonitis (thickening of septa, moderate congestion, infiltration of mononuclear cells and polymorphonuclear leukocytes). After 1, 7, or 14 days recovery there were no or only slight pulmonary problems. There was localization of particles at surfaces facing, deflecting or slowing air currents, particularly near pleura and hilus and less in central portion of lobes. Rabbits exposed to abovemore » dust plus aqueous wetting agent aerosol averaging 0.5 ..mu..m in diameter showed no cyanosis or marked respiratory difficulty. Rabbits showed less of above pulmonary changes and lesser amount of dust in lungs, particularly in alveoli and alveolar ducts. Most particles were cleared in 1 day in both groups, especially aerosol group, and essentially were all gone after 7 days. Differences were primarily due to coating of particles with liquid (increased size) and aggregation.« less

30 CFR 90.301 - Respirable dust control plan; approval by District Manager; copy to part 90 miner.

Code of Federal Regulations, 2010 CFR

2010-07-01

... District Manager; copy to part 90 miner. 90.301 Section 90.301 Mineral Resources MINE SAFETY AND HEALTH... control plan; approval by District Manager; copy to part 90 miner. (a) The District Manager will approve... District Manager shall consider whether: (1) The respirable dust control measures would be likely to...

Assessment of potential concerns associated with the use of cement kiln baghouse dust in FDOT concrete mixes.

DOT National Transportation Integrated Search

2013-08-01

As a means of controlling mercury (Hg) stack emissions at cement kiln operations, some facilities have proposed or have instituted a practice known as dust shuttling, where baghouse filter dust (BFD) is routed to be blended with the final cement prod...

Grain dust originating from organic and conventional farming as a potential source of biological agents causing respiratory diseases in farmers.

PubMed

Zukiewicz-Sobczak, Wioletta A; Cholewa, Grażyna; Krasowska, Ewelina; Chmielewska-Badora, Jolanta; Zwoliński, Jacek; Sobczak, Paweł

2013-12-01

Agricultural producers are exposed to a number of different health risks associated with their work environment. The objective of the study was to assess the degree of colonization by fungi in terms of quantity and in terms of variety of species the samples taken from the settled dust from combine threshing of rye cultivation from organic and conventional farms in the Province of Lublin. This paper is a preliminary quantitative assessment of the species of fungi colonizing the samples of settled dust collected during combine threshing from organic and conventional farms in the Province of Lublin. One of the stages of the project was the classification of biosafety BSL (biosafety level) of selected isolates and API ZYM tests to evaluate the potential ability of isolates to cause adverse health effects. To determine the concentration and composition of fungi in collected samples plate dilution method was used with two media: Malt Agar and Potato Dextrose Agar. MOST COMMONLY ISOLATED FUNGI IN SETTLED DUST SAMPLES COLLECTED DURING COMBINE THRESHING FROM ORGANIC FARMS, ON PDA MEDIUM WERE: Alternaria alternata and Aureobasidium pullulans. Cultures on MA medium were dominated by Alternaria alternata, Mycelia sterilia and Fusarium poae. In samples of dust from conventional crops, the predominant species was Alternaria alternata on PDA medium and on MA medium. The obtained results show a potential risk of people involved in agricultural work.

Phytoplankton growth response to Asian dust addition in the northwest Pacific Ocean versus the Yellow Sea

NASA Astrophysics Data System (ADS)

Zhang, Chao; Gao, Huiwang; Yao, Xiaohong; Shi, Zongbo; Shi, Jinhui; Yu, Yang; Meng, Ling; Guo, Xinyu

2018-02-01

In this study, five on-board microcosm experiments were performed in the subtropical gyre, the Kuroshio Extension region of the northwest Pacific Ocean (NWPO), and the Yellow Sea (YS) in order to investigate phytoplankton growth following the addition of artificially modified mineral dust (AM dust) and various nutrients (nitrogen (N), phosphorus (P), iron (Fe), N + P, and N + P + Fe). The two experiments carried out with AM-dust addition in the subtropical gyre showed a maximum chlorophyll a (Chl a) concentration increase of 1.7- and 2.8-fold, while the cell abundance of large-sized phytoplankton ( > 5 µm) showed a 1.8- and 3.9-fold increase, respectively, relative to the controls. However, in the Kuroshio Extension region and the YS, the increases in maximum Chl a and cell abundance of large-sized phytoplankton following AM-dust addition were at most 1.3-fold and 1.7-fold larger than those in the controls, respectively. A net conversion efficiency index (NCEI) newly proposed in this study, size-fractionated Chl a, and the abundance of large-sized phytoplankton were analysed to determine which nutrients contribute to supporting phytoplankton growth. Our results demonstrate that a combination of nutrients, N-P or N + P + Fe, is responsible for phytoplankton growth in the subtropical gyre following AM-dust addition. Single nutrient addition, i.e., N in the Kuroshio Extension region and P or N in the YS, controls the phytoplankton growth following AM-dust addition. In the AM-dust-addition experiments, in which the increased N-P or P was identified to determine phytoplankton growth, the dissolved inorganic P from AM dust (8.6 nmol L-1) was much lower than the theoretically estimated minimum P demand (˜ 20 nmol L-1) for phytoplankton growth. These observations suggest that additional supply augments the bioavailable P stock in incubated seawater with AM-dust addition, most likely due to an enhanced solubility of P from AM dust or the remineralization of the dissolved organic P.

Association between Occupational Exposure to Wood Dust and Cancer: A Systematic Review and Meta-Analysis

PubMed Central

Alonso-Sardón, Montserrat; Chamorro, Antonio-J.; Hernández-García, Ignacio; Iglesias-de-Sena, Helena; Martín-Rodero, Helena; Herrera, Cristian; Marcos, Miguel; Mirón-Canelo, José Antonio

2015-01-01

Objective To perform a systematic review to analyze the association between occupational exposure to wood dust and cancer. Methods A systematic literature search of entries made in the MEDLINE-PubMed database between 1957 and 2013 was conducted to identify studies that had assessed the relationship between occupational exposure to wood dust and different types of cancer. A meta-analysis of selected case-control and cohort studies was subsequently performed. Results A total of 114 studies were identified and 70 were selected for review. Of these, 42 studies focused on the relationship between wood dust and nasal cancer (n = 22), lung cancer (n = 11), and other types of cancer (n = 9). Low-to-moderate quality evidence that wood dust acts as a carcinogen was obtained, and a stronger association between wood dust and nasal adenocarcinoma was observed. A lesser association between wood dust exposure and lung cancer was also observed. Several studies suggested that there is a relationship between wood dust and the onset of other cancers, although there was no evidence to establish an association. A meta-analysis that included four case-controls studies showed that workers exposed to wood dust exhibited higher rates of nasal adenocarcinoma than other workers (odds ratio = 10.28; 95% confidence interval: 5.92 and 17.85; P<0,0001), although a large degree of heterogeneity was found. Conclusions Low-to-moderate quality evidence supports a causal association between cancer and occupational exposure to wood dust, and this association was stronger for nasal adenocarcinoma than for lung cancer. There was no evidence of an association between wood dust exposure and the other cancers examined. PMID:26191795

Evaluation of Nasal Mucociliary Transport Rate byTc-Macroaggregated Albumin Rhinoscintigraphy in Woodworkers.

PubMed

Dostbil, Zeki; Polat, Cahit; Uysal, Ismail Önder; Bakır, Salih; Karakuş, Askeri; Altındağ, Serdar

2011-01-01

Woodworkers in the furniture industry are exposed to wood dust in their workplaces. The aim of this study is to investigate the effect of occupational wood dust exposure on the nasal mucociliary transport rates (NMTRs) in woodworkers. Twenty five woodworkers and 30 healthy controls were included in this study. Wood dust concentration in workplaces was measured using the sampling device. (99m) Tc-macroaggregated albumin ((99m)Tc-MAA) rhinoscintigraphy was performed, and NMTR was calculated in all cases. In statistical analysis, an independent samples t-test was used to compare NMTR of woodworkers and control subjects. We found that the mean NMTR of the woodworkers was lower than that of the healthy controls. However, there was not a statistically significant difference between them (P = 0.066). In conclusion, our findings suggested that wood dust exposure may not impair nasal mucociliary transport rate in woodworkers employed in joinery workshops.

Evaluation of Nasal Mucociliary Transport Rate by99mTc-Macroaggregated Albumin Rhinoscintigraphy in Woodworkers

PubMed Central

Dostbil, Zeki; Polat, Cahit; Uysal, İsmail Önder; Bakır, Salih; Karakuş, Askeri; Altındağ, Serdar

2011-01-01

Woodworkers in the furniture industry are exposed to wood dust in their workplaces. The aim of this study is to investigate the effect of occupational wood dust exposure on the nasal mucociliary transport rates (NMTRs) in woodworkers. Twenty five woodworkers and 30 healthy controls were included in this study. Wood dust concentration in workplaces was measured using the sampling device. 99m Tc-macroaggregated albumin (99mTc-MAA) rhinoscintigraphy was performed, and NMTR was calculated in all cases. In statistical analysis, an independent samples t-test was used to compare NMTR of woodworkers and control subjects. We found that the mean NMTR of the woodworkers was lower than that of the healthy controls. However, there was not a statistically significant difference between them (P = 0.066). In conclusion, our findings suggested that wood dust exposure may not impair nasal mucociliary transport rate in woodworkers employed in joinery workshops. PMID:21804940

Variation in Rising Limb of Colorado River Snowmelt Runoff Hydrograph Controlled by Dust Radiative Forcing in Snow

NASA Astrophysics Data System (ADS)

Painter, Thomas H.; Skiles, S. McKenzie; Deems, Jeffrey S.; Brandt, W. Tyler; Dozier, Jeff

2018-01-01

Common practice and conventional wisdom hold that fluctuations in air temperature control interannual variability in snowmelt and subsequent river runoff. However, recent observations in the Upper Colorado River Basin confirm that net solar radiation and by extension radiative forcing by dust deposited on snow cover exerts the primary forcing on snowmelt. We show that the variation in the shape of the rising limb of the annual hydrograph is controlled by variability in dust radiative forcing and surprisingly is independent of variations in winter and spring air temperatures. These observations suggest that hydroclimatic modeling must be improved to account for aerosol forcings of the water cycle. Anthropogenic climate change will likely reduce total snow accumulations and cause snowmelt runoff to occur earlier. However, dust radiative forcing of snowmelt is likely consuming important adaptive capacity that would allow human and natural systems to be more resilient to changing hydroclimatic conditions.

The Role of Boundary-Layer and Cumulus Convection on Dust Emission, Mixing, and Transport Over Desert Regions

NASA Astrophysics Data System (ADS)

Takemi, T.; Yasui, M.

2005-12-01

Recent studies on dust emission and transport have been concerning the small-scale atmospheric processes in order to incorporate them as a subgrid-scale effect in large-scale numerical prediction models. In the present study, we investigated the dynamical processes and mechanisms of dust emission, mixing, and transport induced by boundary-layer and cumulus convection under a fair-weather condition over a Chinese desert. We performed a set of sensitivity experiments as well as a control simulation in order to examine the effects of vertical wind shear, upper-level wind speed, and moist convection by using a simplified and idealized modeling framework. The results of the control experiment showed that surface dust emission was at first caused before the noon time by intense convective motion which not only developed in the boundary layer but also penetrated into the free troposphere. In the afternoon hours, boundary-layer dry convection actively mixed and transported dust within the boundary layer. Some of the convective cells penetrated above the boundary layer, which led to the generation of cumulus clouds and hence gradually increased the dust content in the free troposphere. Coupled effects of the dry and moist convection played an important role in inducing surface dust emission and transporting dust vertically. This was clearly demonstrated through the comparison of the results between the control and the sensitivity experiments. The results of the control simulation were compared with lidar measurements. The simulation well captured the observed diurnal features of the upward transport of dust. We also examined the dependence of the simulated results on grid resolution: the grid size was changed from 250 m up to 4 km. It was found that there was a significant difference between the 2-km and 4-km grids. If a cumulus parameterization was added to the 4-km grid run, the column content was comparable to the other cases. This result suggests that subgrid parameterizations are required if the grid size is larger than the order of 1 km in a fair-weather condition.

Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic

NASA Astrophysics Data System (ADS)

Schepanski, Kerstin; Heinold, Bernd; Tegen, Ina

2017-09-01

The outflow of dust from the northern African continent towards the North Atlantic is stimulated by the atmospheric circulation over North Africa, which modulates the spatio-temporal distribution of dust source activation and consequently the entrainment of mineral dust into the boundary layer, as well as the transport of dust out of the source regions. The atmospheric circulation over the North African dust source regions, predominantly the Sahara and the Sahel, is characterized by three major circulation regimes: (1) the harmattan (trade winds), (2) the Saharan heat low (SHL), and (3) the West African monsoon circulation. The strength of the individual regimes controls the Saharan dust outflow by affecting the spatio-temporal distribution of dust emission, transport pathways, and deposition fluxes.This study aims at investigating the atmospheric circulation pattern over North Africa with regard to its role favouring dust emission and dust export towards the tropical North Atlantic. The focus of the study is on summer 2013 (June to August), during which the SALTRACE (Saharan Aerosol Long-range TRansport and Aerosol-Cloud interaction Experiment) field campaign also took place. It involves satellite observations by the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) flying on board the geostationary Meteosat Second Generation (MSG) satellite, which are analysed and used to infer a data set of active dust sources. The spatio-temporal distribution of dust source activation frequencies (DSAFs) allows for linking the diurnal cycle of dust source activations to dominant meteorological controls on dust emission. In summer, Saharan dust source activations clearly differ from dust source activations over the Sahel regarding the time of day when dust emission begins. The Sahara is dominated by morning dust source activations predominantly driven by the breakdown of the nocturnal low-level jet. In contrast, dust source activations in the Sahel are predominantly activated during the second half of the day, when downdrafts associated with deep moist convection are the major atmospheric driver. Complementary to the satellite-based analysis on dust source activations and implications from their diurnal cycle, simulations on atmosphere and dust life cycle were performed using the mesoscale atmosphere-dust model system COSMO-MUSCAT (COSMO: COnsortium for Small-scale MOdelling; MUSCAT: MUltiScale Chemistry Aerosol Transport Model). Fields from this simulation were analysed regarding the variability of the harmattan, the Saharan heat low, and the monsoon circulation as well as their impact on the variability of the Saharan dust outflow towards the North Atlantic. This study illustrates the complexity of the interaction among the three major circulation regimes and their modulation of the North African dust outflow. Enhanced westward dust fluxes frequently appear following a phase characterized by a deep SHL. Ultimately, findings from this study contribute to the quantification of the interannual variability of the atmospheric dust burden.

Climate Effects and Efficacy of Dust and Soot in Snow

NASA Astrophysics Data System (ADS)

Zender, C. S.; Flanner, M. G.; Randerson, J. T.; Mahowald, N. M.; Rasch, P. J.; Yoshioka, M.; Painter, T.

2006-12-01

Dust and industrial and biomass burning emissions from low and mid-latitudes dominate the absorbing impurities trapped in snow at mid- and high-latitudes. We study the effects of dust and smoke on global and regional climate using a general circulation model driven by observed and predicted aerosol emissions determined from satellite and in situ observations. The model has sophisticated treatments of aerosol and snowpack radiative and thermodynamic processes that compare well with observations of snow albedo evolution and impurity concentration. This presentation focuses on the individual and combined contributions of present day dust and soot to snow-albedo forcing and on the global temperature and snowpack responses. Results are emphasized near India and East Asia, where the anthropogenic aerosol forcing of surface albedo and hydrology is greatest. We find that dust and black carbon (BC) aerosols have climate change efficacies (surface temperature change per unit forcing) about 3--4 times greater than CO2, making them the most efficacious forcing agents known. We estimate present day dust and soot snowpack-forcing of ~ 0.050 W m-2 warms global climate by ~ 0.16 °K. Anthropogenic soot from fossil fuel sources causes more than 50% of this warming, and biomass burning can account for up to 30% in strong tropical or boreal burn years. The greatest forcings occur in the Tarim/Mongol region (due to dust), northeastern China (due to soot), and the Tibetan Plateau (both). Dirty springtime snow in these regions can darken albedo by more than 0.1 and increase surface absorption by more than 20 W m-2. These results have implications for the strength of the Asian Monsoon, which is negatively correlated with antecedent snow cover in non-ENSO years. Dust and soot have such strong efficacies because they increase spring melt rates thus reduce summer snow cover. In some regions and seasons, dirty snow reduces snowpack depth and cover by 50%, triggering strong snow and sea-ice albedo feedbacks.

Analysis of dust samples from the Middle East using high-density resequencing micro-array RPM-TEI

NASA Astrophysics Data System (ADS)

Leski, T. A.; Gregory, M. J.; Malanoski, A. P.; Smith, J. P.; Glaven, R. H.; Wang, Z.; Stenger, D. A.; Lin, B.

2010-04-01

A previously developed resequencing microarray, "Tropical and Emerging Infections (RPM-TEI v.1.0 chip)", designed to identify and discriminate between tropical diseases and other potential biothreat agents, their near-neighbor species, and/or potential confounders, was used to characterize the microbes present in the silt/clay fraction of surface soils and airborne dust collected from the Middle East. Local populations and U.S. military personnel deployed to the Middle East are regularly subjected to high levels of airborne desert dust containing a significant fraction of inhalable particles and some portion require clinical aid. Not all of the clinical symptoms can be directly attributed to the physical action of material in the human respiratory tract. To better understand the potential health effects of the airborne dust, the composition of the microbial communities associated with surface soil and/or airborne dust (air filter) samples from 19 different sites in Iraq and Kuwait was identified using RPM-TEI v.1.0. Results indicated that several microorganisms including a class of rapidly growing Mycobacterium, Bacillus, Brucella, Clostridium and Coxiella burnetti, were present in the samples. The presence of these organisms in the surface soils and the inhalable fraction of airborne dust analyzed may pose a human health risk and warrants further investigation. Better understanding of the factors influencing the composition of these microbial communities is important to address questions related to human health and is critical to achieving Force Health Protection for the Warfighter operating in the Middle East, Afghanistan, North Africa and other arid regions.

Long-term variability of dust events in Iceland (1949-2011)

NASA Astrophysics Data System (ADS)

Dagsson-Waldhauserova, P.; Arnalds, O.; Olafsson, H.

2014-06-01

Long-term frequency of atmospheric dust observations was investigated for the southern part of Iceland and merged with results obtained from the Northeast Iceland (Dagsson-Waldhauserova et al., 2013). In total, over 34 dust days per year on average occurred in Iceland based on conventionally used synoptic codes for dust. Including codes 04-06 into the criteria for dust observations, the frequency was 135 dust days annually. The Sea Level Pressure (SLP) oscillation controlled whether dust events occurred in NE (16.4 dust days annually) or in southern part of Iceland (about 18 dust days annually). The most dust-frequent decade in S Iceland was the 1960s while the most frequent decade in NE Iceland was the 2000s. A total of 32 severe dust storms (visibility < 500 m) was observed in Iceland with the highest frequency during the 2000s in S Iceland. The Arctic dust events (NE Iceland) were typically warm and during summer/autumn (May-September) while the Sub-Arctic dust events (S Iceland) were mainly cold and during winter/spring (March-May). About half of dust events in S Iceland occurred in winter or at sub-zero temperatures. A good correlation was found between PM10 concentrations and visibility during dust observations at the stations Vik and Storhofdi. This study shows that Iceland is among the dustiest areas of the world and dust is emitted the year-round.

The Coupled Mars Dust and Water Cycles: Understanding How Clouds Affect the Vertical Distribution and Meridional Transport of Dust and Water.

NASA Technical Reports Server (NTRS)

Kahre, M. A.

2015-01-01

The dust and water cycles are crucial to the current Martian climate, and they are coupled through cloud formation. Dust strongly impacts the thermal structure of the atmosphere and thus greatly affects atmospheric circulation, while clouds provide radiative forcing and control the hemispheric exchange of water through the modification of the vertical distributions of water and dust. Recent improvements in the quality and sophistication of both observations and climate models allow for a more comprehensive understanding of how the interaction between the dust and water cycles (through cloud formation) affects the dust and water cycles individually. We focus here on the effects of clouds on the vertical distribution of dust and water, and how those vertical distributions control the net meridional transport of water. For this study, we utilize observations of temperature, dust and water ice from the Mars Climate Sounder (MCS) on the Mars Reconnaissance Orbiter (MRO) combined with the NASA ARC Mars Global Climate Model (MGCM). We demonstrate that the magnitude and nature of the net meridional transport of water between the northern and southern hemispheres during NH summer is sensitive to the vertical structure of the simulated aphelion cloud belt. We further examine how clouds influence the atmospheric thermal structure and thus the vertical structure of the cloud belt. Our goal is to identify and understand the importance of radiative/dynamic feedbacks due to the physical processes involved with cloud formation and evolution on the current climate of Mars.

The Mars Dust and Water Cycles: Investigating the Influence of Clouds on the Vertical Distribution and Meridional Transport of Dust and Water.

NASA Technical Reports Server (NTRS)

Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Brecht, A. S.; Urata, R.

2015-01-01

The dust and water cycles are critical to the current Martian climate, and they interact with each other through cloud formation. Dust modulates the thermal structure of the atmosphere and thus greatly influences atmospheric circulation. Clouds provide radiative forcing and control the net hemispheric transport of water through the alteration of the vertical distributions of water and dust. Recent advancements in the quality and sophistication of both climate models and observations enable an increased understanding of how the coupling between the dust and water cycles (through cloud formation) impacts the dust and water cycles. We focus here on the effects of clouds on the vertical distributions of dust and water and how those vertical distributions control the net meridional transport of water. We utilize observations of temperature, dust and water ice from the Mars Climate Sounder (MCS) on the Mars Reconnaissance Orbiter (MRO) and the NASA ARC Mars Global Climate Model (MGCM) to show that the magnitude and nature of the hemispheric exchange of water during NH summer is sensitive to the vertical structure of the simulated aphelion cloud belt. Further, we investigate how clouds influence atmospheric temperatures and thus the vertical structure of the cloud belt. Our goal is to isolate and understand the importance of radiative/dynamic feedbacks due to the physical processes involved with cloud formation and evolution on the current climate of Mars.

The Mars Dust and Water Cycles: Investigating the Influence of Clouds on the Vertical Distribution and Meridional Transport of Dust and Water

NASA Astrophysics Data System (ADS)

Kahre, Melinda A.; Haberle, Robert M.; Hollingsworth, Jeffery L.; Brecht, Amanda S.; Urata, Richard A.

2015-11-01

The dust and water cycles are critical to the current Martian climate, and they interact with each other through cloud formation. Dust modulates the thermal structure of the atmosphere and thus greatly influences atmospheric circulation. Clouds provide radiative forcing and control the net hemispheric transport of water through the alteration of the vertical distributions of water and dust. Recent advancements in the quality and sophistication of both climate models and observations enable an increased understanding of how the coupling between the dust and water cycles (through cloud formation) impacts the dust and water cycles. We focus here on the effects of clouds on the vertical distributions of dust and water and how those vertical distributions control the net meridional transport of water. We utilize observations of temperature, dust and water ice from the Mars Climate Sounder (MCS) on the Mars Reconnaissance Orbiter (MRO) and the NASA ARC Mars Global Climate Model (MGCM) to show that the magnitude and nature of the hemispheric exchange of water during NH summer is sensitive to the vertical structure of the simulated aphelion cloud belt. Further, we investigate how clouds influence atmospheric temperatures and thus the vertical structure of the cloud belt. Our goal is to isolate and understand the importance of radiative/dynamic feedbacks due to the physical processes involved with cloud formation and evolution on the current climate of Mars.

Bioaccessibility and Speciation of Potential Toxicants in Some Geogenic Sources of Atmospheric Particulate Matter

NASA Astrophysics Data System (ADS)

Morman, S. A.; Wolf, R. E.; Plumlee, G.; Reynolds, R. L.

2008-12-01

The correlation of exposure to particulate matter (PM) and increased morbidity and mortality was established in the 1970's. Research focused on elucidating mechanisms of action (i.e. particle size, composition, and biodurability), has generally examined anthropogenic sources such as solid or liquid combustion byproducts of fossil fuels, byproducts from the smelting of metal ores, and commercial/industrial mineral dusts (asbestos, crystalline silica. metal dusts). While many studies exist on agricultural exposures to inorganic dust, far fewer have examined health issues related to particulate matter contributions from rural, non-agricultural dusts or other geogenic sources. Geogenic PM (produced by natural processes such as volcanic ash, volcanic fog (vog), dusts from dry lakes or glacial deposits, smoke and windborne ash from wildfires, and dusts containing various soil pathogens) and geoanthropogenic PM (produced from natural sources by processes that are modified or enhanced by human activities such as dusts from lakebeds dried by human removal of water, dusts produced from areas that have undergone desertification as a result of human practices etc.) are increasingly recognized as potential agents of toxicity and disease, via both environmental and occupational exposures. Surface sediment on some dry lake beds may contribute significant amounts of mineral dusts to the atmospheric load. For example, Owens Lake (a dry lake in southern California) has been a major source of PM10 (particulate matter less than 10 micrometers) dust in the United States. Dusts from dry and drying saline lakes may contain high concentrations of metals, such as arsenic, with known human health toxicity. Wildfires, consuming over nine million acres in 2007, also contribute significant amounts of particulate matter in addition to their other hazards. Designed to estimate the bioaccessibility of metals in soils, dusts and other environmental materials by measuring the reactivity of the materials in simulated body fluids (SBFs), physiologically based extraction tests (PBETs) are an inexpensive, acellular in vitro test. Bioaccessibility, defined as the fraction of a potential toxicant that becomes soluble in the SBF (e.g. gastric, intestinal, lung or lysosomal fluid), is an indication of the amounts of a potential toxicant that may be available for absorption through ingestion or inhalation. PBETs were conducted on artificially generated dust samples from playas in the Mojave Desert and soil and ash samples from recent California wildfires. Speciation, an important factor in assessing toxicity, was evaluated using high performance liquid chromatography (HPLC) separation with ICP-MS detection for arsenic and chromium.

Occupational exposure to wood dust and risk of nasal and nasopharyngeal cancer: A case-control study among men in four nordic countries-With an emphasis on nasal adenocarcinoma.

PubMed

Siew, Sie Sie; Martinsen, Jan Ivar; Kjaerheim, Kristina; Sparén, Pär; Tryggvadottir, Laufey; Weiderpass, Elisabete; Pukkala, Eero

2017-12-15

The current study aims to provide stronger evidence to aid in our understanding of the role of cumulative occupational exposure to (softwood-dominated) mixed wood dust in aetiology of nasal cancer. We included broad exposure occurred in a range of wood-processing occupation across varied industries in four Nordic countries. A population-based case-control study was conducted on all male cases with nasal adenocarcinoma (393 cases), other types of nasal cancer (2,446) and nasopharyngeal cancer (1,747) diagnosed in Finland, Sweden, Norway and Iceland between 1961 and 2005. For each case, five male controls, who were alive at the time of diagnosis of the case (index date), were randomly selected, matched by birth-year and country. Cumulative exposures (CE)s to wood dust and formaldehyde before the index date were quantified based on a job-exposure matrix linked to occupational titles derived from population censuses. Hazard ratios (HRs) for the CE of wood dust were estimated by conditional logistic regression, adjusted for CE to formaldehyde and 95% confidence intervals (CIs) were calculated. There was an increasing risk of nasal adenocarcinoma related to wood dust exposure. The HR in the highest CE category of wood dust (≥ 28.82 mg/m 3 -years) was 16.5 (95% CI 5.05-54.1). Neither nonadenocarcinoma of the nose nor nasopharyngeal cancer could be linked to wood dust exposure. CE to softwood-dominated mixed wood dusts is strongly linked with elevated risk in nasal adenocarcinoma but not with other types of nasal or nasopharyngeal cancer. © 2017 UICC.

Research and application of non-traditional chemical stabilizers on bauxite residue (red sand) dust control, a review.

PubMed

Xu, Guang; Ding, Xuhan; Kuruppu, Mahinda; Zhou, Wei; Biswas, Wahidul

2018-03-01

Bauxite residue is a by-product of aluminium processing. It is usually stored in large-scale residue drying area (RDA). The bauxite residue is highly alkaline and contains a large percentage of metal oxides which are hazardous to the environment and human health. Therefore, the generated dust is a major environmental concern that needs to be addressed and efficiently managed. One of the major dust generation sources is from the coarse fraction of the bauxite residue named red sand. To minimize the environmental and health impacts, non-traditional chemical stabilizers can be applied to construct a binding surface crust with certain hardness and strength. Dust emission is reduced due to the increased moisture retention capacity and strong cohesion between sand particles. There are limited number of refereed publications that discuss the application of this method to alleviate dust generation from red sand. By critically reviewing the literature and the application of non-traditional chemical stabilizers to sand-like materials in other fields, this paper introduces some non-traditional chemical stabilizers that can be potentially used for controlling red sand dust. Commonly used evaluation methods in various studies are compared and summarized; the stabilization mechanisms are examined; and the performance of three types of stabilizers are compared and evaluated. This review potentially serves as a reference and guide for further studies in red sand dust control. The findings are especially useful for developing suitable quantitative methods for evaluating the dust suppression efficiency of soil stabilizers, and for determining the appropriate additive quantities that achieve both economic and performance effectiveness. Copyright © 2017 Elsevier B.V. All rights reserved.

Tungsten dust remobilization under steady-state and transient plasma conditions

DOE PAGES

Ratynskaia, S.; Tolias, P.; De Angeli, M.; ...

2016-11-22

Remobilization is one of the most prominent unresolved fusion dust-relevant issues, strongly related to the lifetime of dust in plasma-wetted regions, the survivability of dust on hot plasma-facing surfaces and the formation of dust accumulation sites. A systematic cross-machine study has been initiated to investigate the remobilization of tungsten micron-size dust from tungsten surfaces implementing a newly developed technique based on controlled pre-adhesion by gas dynamics methods. It has been utilized in a number of devices and has provided new insights on remobilization under steady-state and transient conditions. In conclusion, the experiments are interpreted with contact mechanics theory and heatmore » conduction models.« less

Comparison of conventional and bio-treated methods as dust suppressants.

PubMed

Naeimi, Maryam; Chu, Jian

2017-10-01

Dust is an environmental, geotechnical, health, and economical hazard. Fugitive dust emanating along transportation systems such as roads, railways, and airports especially can have significant impacts on health, safety, material loss, cost of maintenance, and interfere with the facilities. Quantitative studies on the effectiveness of the proper dust palliatives and their environmental impact have been studied with a number of biological and chemical methods. The objective of this study was to establish a method for using the microbial Induced calcium carbonate precipitation (MICP) approach to reduce the percent of mass loss against erosive force of wind regarding to the concentration and characteristics of aggregate used, climate, and traffic amounts. The results of this study showed that the required precipitation for dust control of sand by 70% is less than 15 g CaCO 3 /m 2 between sand grains in bio-treated sand. The wind tunnel test results of this study also indicate that the effectiveness of the bio-treatment method for dust control depends on many variables, such as the percent of precipitated calcium carbonate and tensile strength.

Fipronil and its degradates in indoor and outdoor dust

USGS Publications Warehouse

Mahler, B.J.; Van Metre, P.C.; Wilson, J.T.; Musgrove, M.; Zaugg, S.D.; Burkhardt, M.R.

2009-01-01

Fipronil is a potent insecticide used for control of termites, fleas, roaches, ants, and other pests. We measured fipronil, fipronil sulfide, and desulfinyl fipronil concentrations in indoor and outdoor dust from 24 residences in Austin, Texas. At least one of these three fipronil compounds was detected in every sample. Fipronil accounted for most of the total fipronil (T-fipronil; fipronil+desulfinyl fipronil+fipronil sulfide), followed by desulfinyl fipronil and fipronil sulfide. Nineteen of 24 samples of indoor dust had T-fipronil concentrations less than 270 ??g/kg; the remaining five had concentrations from 1320 to 14,200 ??g/kg. All three of the residences with a dog on which a flea-control product containing fipronil was used were among the five residences with elevated fipronil concentrations. In outdoor dust, all concentrations of T-fipronil were less than 70??g/kg with one exception (430??g/kg). For every residence, the concentration of T-fipronil in indoor dust exceeded that in outdoor dust, and the median concentration of T-fipronil was 15 times higher indoors than outdoors.

Effectiveness of dust control methods for crystalline silica and respirable suspended particulate matter exposure during manual concrete surface grinding.

PubMed

Akbar-Khanzadeh, Farhang; Milz, Sheryl A; Wagner, Cynthia D; Bisesi, Michael S; Ames, April L; Khuder, Sadik; Susi, Pam; Akbar-Khanzadeh, Mahboubeh

2010-12-01

Concrete grinding exposes workers to unacceptable levels of crystalline silica dust, known to cause diseases such as silicosis and possibly lung cancer. This study examined the influence of major factors of exposure and effectiveness of existing dust control methods by simulating field concrete grinding in an enclosed workplace laboratory. Air was monitored during 201 concrete grinding sessions while using a variety of grinders, accessories, and existing dust control methods, including general ventilation (GV), local exhaust ventilation (LEV), and wet grinding. Task-specific geometric mean (GM) of respirable crystalline silica dust concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled-grinding, while GV was off/on, were 0.17/0.09, 0.57/0.13, 1.11/0.44, and 23.1/6.80, respectively. Silica dust concentrations (mg/m³ using 100-125 mm (4-5 inch) and 180 mm (7 inch) grinding cups were 0.53/0.22 and 2.43/0.56, respectively. GM concentrations of silica dust were significantly lower for (1) GV on (66.0%) vs. off, and (2) LEV:HEPA- (99.0%), LEV:Shop-vac- (98.1%) or wet- (94.4%) vs. uncontrolled-grinding. Task-specific GM of respirable suspended particulate matter (RSP) concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled grinding, while GV was off/on, were 1.58/0.63, 7.20/1.15, 9.52/4.13, and 152/47.8, respectively. GM concentrations of RSP using 100-125 mm and 180 mm grinding cups were 4.78/1.62 and 22.2/5.06, respectively. GM concentrations of RSP were significantly lower for (1) GV on (70.2%) vs. off, and (2) LEV:HEPA- (98.9%), LEV:Shop-vac- (96.9%) or wet- (92.6%) vs. uncontrolled grinding. Silica dust and RSP were not significantly affected by (1) orientation of grinding surfaces (vertical vs. inclined); (2) water flow rates for wet grinding; (3) length of task-specific sampling time; or, (4) among cup sizes of 100, 115 or 125 mm. No combination of factors or control methods reduced an 8-hr exposure level to below the recommended criterion of 0.025 mg/m³ for crystalline silica, requiring further refinement in engineering controls, administrative controls, or the use of respirators.

The protective role of zinc in the toxic action of coal dust upon mouse macrophages.

PubMed Central

Lai, Y R; Chen, J L; Jiang, X Y; Yang, G K; Yang, S Q; Gao, W X

1991-01-01

Macrophages from mice were cultured at 37 degrees C with 1640 medium containing 10% bovine serum. The macrophage suspension was made from 50 Swiss mice and was cultured in the following groups: control group; coal dust group (with added coal dust particles (10 micrograms/ml) smaller than 4 microns diameter); subdivided zinc-coal dust group (as coal dust group with zinc added in three different concentrations--namely, 10 ppm, 30 ppm, and 60 ppm). Cells were examined by light microscopy. Obvious differences were found in the rate of cell deaths between the coal dust group and the zinc-coal dust group after culture for 48 hours. The cell membranes were ruptured after culturing with coal dust, and the presence of zinc appeared in some degree to protect cell membranes from damage caused by the dust. Staining the cells with Gomori's modified method, showed that acid phosphatase particles in the zinc-coal dust group were more numerous than in the coal dust group. The results indicate that the trace element zinc may play an important part in protecting against the cytotoxic action of coal dust. PMID:1772798

Assessment of State-of-the-Art Dust Emission Scheme in GEOS

NASA Technical Reports Server (NTRS)

Darmenov, Anton; Liu, Xiaohong; Prigent, Catherine

2017-01-01

The GEOS modeling system has been extended with state of the art parameterization of dust emissions based on the vertical flux formulation described in Kok et al 2014. The new dust scheme was coupled with the GOCART and MAM aerosol models. In the present study we compare dust emissions, aerosol optical depth (AOD) and radiative fluxes from GEOS experiments with the standard and new dust emissions. AOD from the model experiments are also compared with AERONET and satellite based data. Based on this comparative analysis we concluded that the new parameterization improves the GEOS capability to model dust aerosols originating from African sources, however it lead to overestimation of dust emissions from Asian and Arabian sources. Further regional tuning of key parameters controlling the threshold friction velocity may be required in order to achieve more definitive and uniform improvement in the dust modeling skill.

77 FR 20700 - Examinations of Work Areas in Underground Coal Mines for Violations of Mandatory Health or Safety...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-06

... safety standards related to ventilation, methane, roof control, combustible materials, rock dust, other... standards related to ventilation, methane, roof control, combustible materials, rock dust, other safeguards... and unsafe conditions, such as methane accumulations, water accumulations, and adverse roof conditions...

Environmental impacts of oil and gas brine applications for dust and ice control in New York : final report.

DOT National Transportation Integrated Search

2016-04-01

Transportation agencies are required to treat roads for dust and ice control to ensure adequate safety for travelers. This is commonly achieved through application of solid and liquid chemicals. These materials can be conventional rock salt, brine fr...

Guidance for Selecting Legitimate Recycling Products and Processes

DTIC Science & Technology

1998-10-23

information you have provided on the GIL glassification process for electric arc furnace ( EAF ) dust or K061 when the EAF dust is a hazardous waste. Based on the...regarding the regulatory status of the GIL process and glass frit product has been whether EAF dust incorporated into GIL glass frit meets the definition...emission control dust from a primary copper smelter could be returned to any part of the process associated with copper production. The material also cannot

North African dust emissions and transport

NASA Astrophysics Data System (ADS)

Engelstaedter, Sebastian; Tegen, Ina; Washington, Richard

2006-11-01

The need for a better understanding of the role of atmospheric dust in the climate system and its impact on the environment has led to research of the underlying causes of dust variability in space and time in recent decades. North Africa is one of the largest dust producing regions in the world with dust emissions being highly variable on time scales ranging from diurnal to multiannual. Changes in the dust loading are expected to have an impact on regional and global climate, the biogeochemical cycle, and human environments. The development of satellite derived products of global dust distributions has improved our understanding of dust source regions and transport pathways in the recent years. Dust models are now capable of reproducing more realistic patterns of dust distributions due to an improved parameterization of land surface conditions. A recent field campaign has improved our understanding of the natural environment and emission processes of the most intense and persistent dust sources in the world, the Bodélé Depression in Chad. In situ measurements of dust properties during air craft observations in and down wind of source regions have led to new estimates of the radiative forcing effects which are crucial in predicting future climate change. With a focus on the North African desert regions, this paper provides a review of the understanding of dust source regions, the variability of dust emissions, climatic controls of dust entrainment and transport, the role of human impact on dust emission, and recent developments of global and regional dust models.

Occupational exposure to textile dust increases the risk of rheumatoid arthritis: results from a Malaysian population-based case–control study

PubMed Central

Too, Chun Lai; Muhamad, Nor Asiah; Ilar, Anna; Padyukov, Leonid; Alfredsson, Lars; Klareskog, Lars; Murad, Shahnaz; Bengtsson, Camilla

2016-01-01

Objectives Lung exposures including cigarette smoking and silica exposure are associated with the risk of rheumatoid arthritis (RA). We investigated the association between textile dust exposure and the risk of RA in the Malaysian population, with a focus on women who rarely smoke. Methods Data from the Malaysian Epidemiological Investigation of Rheumatoid Arthritis population-based case–control study involving 910 female early RA cases and 910 female age-matched controls were analysed. Self-reported information on ever/never occupationally exposed to textile dust was used to estimate the risk of developing anti-citrullinated protein antibody (ACPA)-positive and ACPA-negative RA. Interaction between textile dust and the human leucocyte antigen DR β-1 (HLA-DRB1) shared epitope (SE) was evaluated by calculating the attributable proportion due to interaction (AP), with 95% CI. Results Occupational exposure to textile dust was significantly associated with an increased risk of developing RA in the Malaysian female population (OR 2.8, 95% CI 1.6 to 5.2). The association between occupational exposure to textile dust and risk of RA was uniformly observed for the ACPA-positive RA (OR 2.5, 95% CI 1.3 to 4.8) and ACPA-negative RA (OR 3.5, 95% CI 1.7 to 7.0) subsets, respectively. We observed a significant interaction between exposure to occupational textile dust and HLA-DRB1 SE alleles regarding the risk of ACPA-positive RA (OR for double exposed: 39.1, 95% CI 5.1 to 297.5; AP: 0.8, 95% CI 0.5 to 1.2). Conclusions This is the first study demonstrating that textile dust exposure is associated with an increased risk for RA. In addition, a gene–environment interaction between HLA-DRB1 SE and textile dust exposure provides a high risk for ACPA-positive RA. PMID:26681695

Airway toxicity of house dust and its fungal composition.

PubMed

Piecková, Elena; Wilkins, Ken

2004-01-01

House dust is an important source of different toxic metabolites as well as allergens, including those of fungal origin, in the indoor environment. A bio-assay employing 1-day-old chick tracheas was used to characterize airway effects of 2-butanone and dimethylsulphoxide (Me2SO) extracts of 23 dust samples collected from water damaged (13) and control (10) Danish schools. Direct microscopical analysis of samples, followed by cultivation on dichloran 18 % glycerol agar at 25 degrees C for 10 days to establish their mycoflora, was performed. The in vitro ciliostatic potential of the chloroform-extractable endo- and exometabolites of 41 representative fungal isolates was determined. Nine dust extracts in 2-butanone (2 from damp rooms) or 10 (6) in Me(2)SO showed some ciliostatic activity in the 3-days' experiment. Fungal composition of dust from buildings with leakage was almost identical with that from undamaged houses, as well as the fungal colony counts from the damp schools and the control samples. Aspergillus spp. were prevalent in the samples - 31 or 40 % of all fungi, followed by Penicillium spp. and Cladosporium cladosporioides. Alternaria spp., Chaetomium spp., Mucor spp., Mycelia sterilia, Paecilomyces variotii, Rhizopus sp., Ulocladium sp. and yeasts were each isolated in less than 8 % of the fungal content. No Aspergillus flavus isolate (8 in total) was aflatoxigenic,em>in vitro. Alternaria spp., Aspergillus spp., Botrytis cinerea, Penicillium spp., C. cladosporioides, Chaetomium spp. and Ulocladium sp.; in total, 88 % of all fungi tested, produced ciliostatically active metabolites. These toxigenic strains were also present in 4 dust samples from controls and 5 dust samples from water damaged buildings. Extracts of these dust samples were also toxic in bioassay. There were bio-detectable concentrations (10-20 microg of extracts/ml of the organ culture medium) of toxic compounds in house dust. Contribution of fungal metabolites to its toxic effect should be studied further.

Effect of a rock dust amendment on disease severity of tomato bacterial wilt.

PubMed

Li, Jian-Gang; Dong, Yuan-Hua

2013-01-01

Nutrients are important for growth and development of plants and microbes, and they are also important factors in plant disease control. The objective of this study was to evaluate the effect of a rock dust used as a fertilizer in maintaining health of soil and tomato plants under greenhouse conditions. Four treatments-including M (commercial organic fertilizer), A (rock dust soil amendment), M + A (commercial organic fertilizer + rock dust soil amendment) and CK (blank control)--were examined for their effect on soil properties, soil enzymatic activity, plant growth and control efficacy against tomato bacterial wilt. Treatments A and M + A were significantly better than other treatments in changing soil pH, increasing it from acidic (pH 5.13) to nearly neutral (pH 6.81 and 6.70, respectively). Enzymatic activities in soil were notably influenced by the different treatments--particularly treatment M + A, which increased the activities of alkaline phosphatase, urease, catalase and sucrase to a greater extent in soil. There was no significant difference (P < 0.05) in the effects of treatments A and M + A on tomato plant height, stem diameter and biomass. The effect of the four treatments on the chlorophyll content and photosynthetic rate (in decreasing order) were M + A, A, M and CK. The replicate greenhouse experiments showed that the control efficacies of treatments M + A, A, and M against bacterial wilt were respectively 89.99, 81.11 and 8.89 % in first experiment and with the efficacies of 84.55, 74.36, and 13.49 % in the replicate; indicating that rock dust played a key role in the plant-soil interaction. The raised soil pH and Ca content were the key factors for the rock dust amendment controlling bacterial wilt under greenhouse conditions.

Effectiveness of interventions to reduce flour dust exposures in supermarket bakeries in South Africa.

PubMed

Baatjies, Roslynn; Meijster, Tim; Heederik, Dick; Sander, Ingrid; Jeebhay, Mohamed F

2014-12-01

A recent study of supermarket bakery workers in South Africa demonstrated that 25% of workers were sensitised to flour allergens and 13% had baker's asthma. Evidence on exposure reduction strategies using specifically designed interventions aimed at reducing the risk of baker's asthma is scarce. The aim of this study was to evaluate the effectiveness of different control measures to reduce airborne flour dust exposure using a randomised design. A group-randomised study design was used to assign 30 bakeries of a large supermarket chain store to two intervention groups and a control group, of which 15 bakeries were studied. Full-shift environmental personal samples were used to characterise exposure to flour dust and wheat and rye allergens levels pre-intervention (n=176) and post-intervention (n=208). The overall intervention effect revealed a 50% decrease in mean flour dust, wheat and rye allergen exposure. The reduction in exposure was highest for managers (67%) and bakers (47%), and lowest for counterhands (23%). For bakers, the greatest reduction in flour dust was associated with control measures such as the use of the mixer lid (67%), divider oil (63%) or focused training (54%). However, the greatest reduction (80%) was observed when using a combination of all control measures. A specially designed intervention strategy reduced both flour dust and allergen levels. Best results were observed when combining both engineering controls and training. Further studies will investigate the long-term health impact of these interventions on reducing the disease burden among this group of bakers. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Agglomeration of dust in convective clouds initialized by nuclear bursts

NASA Astrophysics Data System (ADS)

Bacon, D. P.; Sarma, R. A.

Convective clouds initialized by nuclear bursts are modeled using a two-dimensional axisymmetric cloud model. Dust transport through the atmosphere is studied using five different sizes ranging from 1 to 10,000 μm in diameter. Dust is transported in the model domain by advection and sedimentation. Water is allowed to condense onto dust particles in regions of supersaturation in the cloud. The agglomeration of dust particles resulting from the collision of different size dust particles is modeled. The evolution of the dust mass spectrum due to agglomeration is modeled using a numerical scheme which is mass conserving and has low implicit diffusion. Agglomeration moves mass from the small particles with very small fall velocity to the larger sizes which fall to the ground more readily. Results indicate that the dust fallout can be increased significantly due to this process. In preliminary runs using stable and unstable environmental soundings, at 30 min after detonation the total dust in the domain was 11 and 30%, respectively, less than a control case without agglomeration.

High exposure to respirable dust and quartz in a labour-intensive coal mine in Tanzania.

PubMed

Mamuya, Simon H D; Bråtveit, Magne; Mwaiselage, Julius; Mashalla, Yohana J S; Moen, Bente E

2006-03-01

Labour-intensive mines are numerous in several developing countries, but dust exposure in such mines has not been adequately characterized. The aim of this study was to identify and quantify the determinants of respirable dust and quartz exposure among underground coal mine workers in Tanzania. Personal respirable dust samples (n = 134) were collected from 90 underground workers in June-August 2003 and July-August 2004. The development team had higher exposure to respirable dust and quartz (geometric means 1.80 and 0.073 mg m(-3), respectively) than the mining team (0.47 and 0.013 mg m(-3)), the underground transport team (0.14 and 0.006 mg m(-3)) and the underground maintenance team (0.58 and 0.016 mg m(-3)). The percentages of samples above the threshold limit values (TLVs) of 0.9 mg m(-3) for respirable bituminous coal dust and 0.05 mg m(-3) for respirable quartz, respectively, were higher in the development team (55 and 47%) than in the mining team (20 and 9%). No sample for the underground transport team exceeded the TLV. Drilling in the development was the work task associated with the highest exposure to respirable dust and quartz (17.37 and 0.611 mg m(-3), respectively). Exposure models were constructed using multiple regression model analysis, with log-transformed data on either respirable dust or quartz as the dependent variable and tasks performed as the independent variables. The models for the development section showed that blasting and pneumatic drilling times were major determinants of respirable dust and quartz, explaining 45.2 and 40.7% of the variance, respectively. In the mining team, only blasting significantly determined respirable dust. Immediate actions for improvements are suggested to include implementing effective dust control together with improved training and education programmes for the workers. Dust and quartz in this underground mine should be controlled by giving priority to workers performing drilling and blasting in the development sections of the mine.

Peach leaf responses to soil and cement dust pollution.

PubMed

Maletsika, Persefoni A; Nanos, George D; Stavroulakis, George G

2015-10-01

Dust pollution can negatively affect plant productivity in hot, dry and with high irradiance areas during summer. Soil or cement dust were applied on peach trees growing in a Mediterranean area with the above climatic characteristics. Soil and cement dust accumulation onto the leaves decreased the photosynthetically active radiation (PAR) available to the leaves without causing any shade effect. Soil and mainly cement dust deposition onto the leaves decreased stomatal conductance, photosynthetic and transpiration rates, and water use efficiency due possibly to stomatal blockage and other leaf cellular effects. In early autumn, rain events removed soil dust and leaf functions partly recovered, while cement dust created a crust partially remaining onto the leaves and causing more permanent stress. Leaf characteristics were differentially affected by the two dusts studied due to their different hydraulic properties. Leaf total chlorophyll decreased and total phenol content increased with dust accumulation late in the summer compared to control leaves due to intense oxidative stress. The two dusts did not cause serious metal imbalances to the leaves, except of lower leaf K content.

Effect of desert dust exposure on allergic symptoms: A natural experiment in Japan.

PubMed

Kanatani, Kumiko T; Hamazaki, Kei; Inadera, Hidekuni; Sugimoto, Nobuo; Shimizu, Atsushi; Noma, Hisashi; Onishi, Kazunari; Takahashi, Yoshimitsu; Itazawa, Toshiko; Egawa, Miho; Sato, Keiko; Go, Tohshin; Ito, Isao; Kurozawa, Youichi; Konishi, Ikuo; Adachi, Yuichi; Nakayama, Takeo

2016-05-01

Desert dust originating from arid and semiarid areas is transported to widespread regions, including Japan. Desert dust particles exert adjuvant effects in animals. To examine whether desert dust enhances allergic symptoms in real-life settings and to explore its effect modifiers. We conducted an observational study of 3,327 pregnant women during spring and fall in October 2011 to May 2013 in 3 regions in Japan as an adjunct study of the Japan Environment & Children's Study. We acquired participants' daily symptom scores by sending a questionnaire to their mobile phones on high desert-dust days (>0.07/km) and on some randomly selected other days (control days) for each participant. Pregnant women had an increased risk of allergic symptoms on high desert-dust days (adjusted odds ratio [OR], 1.10; 95% CI, 1.04-1.18). The increased OR was mostly driven by those who showed positive IgE to Japanese cedar pollen when pollen simultaneously dispersed (adjusted OR, 1.25; 95% CI, 1.13-1.38), whereas no clear risk increase was observed in the absence of pollen or for participants with negative IgE to Japanese cedar pollen. The risk elevation was observed from low levels of desert dust in a dose-dependent manner even on control days. Ambient desert dust level was associated with an increased risk of allergic symptoms in pollen-sensitized pregnant women when pollen was present in the air. The risk increase was dose dependent and was observed from low levels of desert dust. These results support a hypothesis that ambient desert dust particles exert adjuvant effects in human in real-life settings. clinicaltrials.gov Identifier: UMIN000010826. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

A 2 MV Van de Graaff accelerator as a tool for planetary and impact physics research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mocker, Anna; Bugiel, Sebastian; Srama, Ralf

Investigating the dynamical and physical properties of cosmic dust can reveal a great deal of information about both the dust and its many sources. Over recent years, several spacecraft (e.g., Cassini, Stardust, Galileo, and Ulysses) have successfully characterised interstellar, interplanetary, and circumplanetary dust using a variety of techniques, including in situ analyses and sample return. Charge, mass, and velocity measurements of the dust are performed either directly (induced charge signals) or indirectly (mass and velocity from impact ionisation signals or crater morphology) and constrain the dynamical parameters of the dust grains. Dust compositional information may be obtained via either time-of-flightmore » mass spectrometry of the impact plasma or direct sample return. The accurate and reliable interpretation of collected spacecraft data requires a comprehensive programme of terrestrial instrument calibration. This process involves accelerating suitable solar system analogue dust particles to hypervelocity speeds in the laboratory, an activity performed at the Max Planck Institut fuer Kernphysik in Heidelberg, Germany. Here, a 2 MV Van de Graaff accelerator electrostatically accelerates charged micron and submicron-sized dust particles to speeds up to 80 km s{sup -1}. Recent advances in dust production and processing have allowed solar system analogue dust particles (silicates and other minerals) to be coated with a thin conductive shell, enabling them to be charged and accelerated. Refinements and upgrades to the beam line instrumentation and electronics now allow for the reliable selection of particles at velocities of 1-80 km s{sup -1} and with diameters of between 0.05 {mu}m and 5 {mu}m. This ability to select particles for subsequent impact studies based on their charges, masses, or velocities is provided by a particle selection unit (PSU). The PSU contains a field programmable gate array, capable of monitoring in real time the particles' speeds and charges, and is controlled remotely by a custom, platform independent, software package. The new control instrumentation and electronics, together with the wide range of accelerable particle types, allow the controlled investigation of hypervelocity impact phenomena across a hitherto unobtainable range of impact parameters.« less

A 2 MV Van de Graaff accelerator as a tool for planetary and impact physics research

NASA Astrophysics Data System (ADS)

Mocker, Anna; Bugiel, Sebastian; Auer, Siegfried; Baust, Günter; Colette, Andrew; Drake, Keith; Fiege, Katherina; Grün, Eberhard; Heckmann, Frieder; Helfert, Stefan; Hillier, Jonathan; Kempf, Sascha; Matt, Günter; Mellert, Tobias; Munsat, Tobin; Otto, Katharina; Postberg, Frank; Röser, Hans-Peter; Shu, Anthony; Sternovsky, Zoltán; Srama, Ralf

2011-09-01

Investigating the dynamical and physical properties of cosmic dust can reveal a great deal of information about both the dust and its many sources. Over recent years, several spacecraft (e.g., Cassini, Stardust, Galileo, and Ulysses) have successfully characterised interstellar, interplanetary, and circumplanetary dust using a variety of techniques, including in situ analyses and sample return. Charge, mass, and velocity measurements of the dust are performed either directly (induced charge signals) or indirectly (mass and velocity from impact ionisation signals or crater morphology) and constrain the dynamical parameters of the dust grains. Dust compositional information may be obtained via either time-of-flight mass spectrometry of the impact plasma or direct sample return. The accurate and reliable interpretation of collected spacecraft data requires a comprehensive programme of terrestrial instrument calibration. This process involves accelerating suitable solar system analogue dust particles to hypervelocity speeds in the laboratory, an activity performed at the Max Planck Institut für Kernphysik in Heidelberg, Germany. Here, a 2 MV Van de Graaff accelerator electrostatically accelerates charged micron and submicron-sized dust particles to speeds up to 80 km s-1. Recent advances in dust production and processing have allowed solar system analogue dust particles (silicates and other minerals) to be coated with a thin conductive shell, enabling them to be charged and accelerated. Refinements and upgrades to the beam line instrumentation and electronics now allow for the reliable selection of particles at velocities of 1-80 km s-1 and with diameters of between 0.05 μm and 5 μm. This ability to select particles for subsequent impact studies based on their charges, masses, or velocities is provided by a particle selection unit (PSU). The PSU contains a field programmable gate array, capable of monitoring in real time the particles' speeds and charges, and is controlled remotely by a custom, platform independent, software package. The new control instrumentation and electronics, together with the wide range of accelerable particle types, allow the controlled investigation of hypervelocity impact phenomena across a hitherto unobtainable range of impact parameters.

Dust Emissions from Undisturbed and Disturbed, Crusted Playa Surfaces: Cattle Trampling Effect

USDA-ARS?s Scientific Manuscript database

Dry playa lake beds can be a significant source of fine dust emissions during high wind events in arid and semiarid landscapes. The physical and chemical properties of the playa surface control the amount and properties of the dust emitted. In this study, we use a field wind tunnel to quantify the...

Structure Formation in Complex Plasma - Quantum Effects in Cryogenic Complex Plasmas

DTIC Science & Technology

2014-09-26

pipe at the flange attached to the inner Dewar bottle. The temperature of the gas in the glass tube is controlled by the cryogenic liquid , liquid ...dust particles. The supersonic flow was possible to make in a complex plasma since dust acoustic wave is characterized by a sound speed of a few cm...through the illumination of laser light on dust particles. The supersonic flow was possible to make in a complex plasma since dust acoustic wave is

Assessment of microbial contamination within working environments of different types of composting plants.

PubMed

Gutarowska, Beata; Skóra, Justyna; Stępień, Łukasz; Szponar, Bogumiła; Otlewska, Anna; Pielech-Przybylska, Katarzyna

2015-04-01

The objective of the study was to determine the degree of microbiological contamination, type of microflora, bioaerosol particle size distribution, and concentration of endotoxins in dust in different types of composting plants. In addition, this study provides a list of indicator microorganisms that pose a biological threat in composting facilities, based on their prevalence within the workplace, source of isolation, and health hazards. We undertook microbiological analysis of the air, work surfaces, and compost, and assessed the particle size distribution of bioaerosols using a six-stage Andersen sampler. Endotoxins were determined using gas chromatography-mass spectrometry (GC-MS). Microbial identification was undertaken both microscopically and using biochemical tests. The predominant bacterial and fungal species were identified using 16S rRNA and ITS1/2 analysis, respectively. The number of mesophilic microorganisms in composting plants amounted to 6.9×10(2)-2.5×10(4) CFU/m3 in the air, 2.9×10(2)-3.3×10(3) CFU/100 cm2 on surfaces, and 2.2×10(5)-2.4×10(7) CFU/g in compost. Qualitative analysis revealed 75 microbial strains in composting plants, with filamentous fungi being the largest group of microorganisms, accounting for as many as 38 isolates. The total amount of endotoxins was 0.0062-0.0140 nmol/mg of dust. The dust fraction with aerodynamic particle diameter of 0.65-1.1 μm accounted for 28-39% of bacterial aerosols and 4-13% of fungal aerosols. We propose the following strains as indicators of harmful biological agent contamination: Bacillus cereus, Aspergillus fumigatus, Cladosporium cladosporioides, C. herbarum, Mucor hiemalis, and Rhizopus oryzae for both types of composting plants, and Bacillus pumilus, Mucor fragilis, Penicillium svalbardense, and P. crustosum for green waste composting plants. The biological hazards posed within these plants are due to the presence of potentially pathogenic microorganisms and the inhalation of respirable bioaerosol. Depending on the type of microorganism, these hazards may be aggravated or reduced after cleaning procedures. This study assessed the microbial contamination in two categories of composting plants: (1) facilities producing substrates for industrial cultivation of button mushrooms, and (2) facilities for processing biodegradable waste. Both workplaces showed potentially pathogenic microorganisms, respirable bioaerosol, and endotoxin. These results are useful to determine the procedures to control harmful biological agents, and to disinfect workplaces in composting plants.

Evaluation of the nasal mucociliary transport rate by rhinoscintigraphy in marble workshop workers.

PubMed

Dostbil, Zeki; Polat, Cahit; Karakus, Askeri; Bakir, Salih; Yuce, Salim

2011-10-01

Marble workers are occupationally exposed to intense environmental marble dust in their workplace. We aimed to investigate the effect of occupational marble dust exposure on nasal mucociliary transport rate (NMTR). Seventeen marble workers and 18 healthy controls were studied. In all subjects, NMTRs were measured by (99m)Tc-MAA rhinoscintigraphy. NMTRs of workers and control groups were compared by statistically. Mean NMTR was found as 9 ± 1.8 mm/min in marble workers whereas mean NMTR of healthy controls was 9.6 ± 2.2 mm/min. There was no statistically significant difference between NMTRs of workers and control groups (p > 0.05). This study has shown that occupationally exposured marble dusts may not cause functional impairment on NMTR in marble workshop workers.

Design of equipment for lunar dust removal

NASA Technical Reports Server (NTRS)

Belden, Lacy; Cowan, Kevin; Kleespies, Hank; Ratliff, Ryan; Shah, Oniell; Shelburne, Kevin

1991-01-01

NASA has a long range goal of constructing a fully equipped, manned lunar base on the near side of the moon by the year 2015. During the Apollo Missions, lunar dust coated and fouled equipment surfaces and mechanisms exposed to the lunar environment. In addition, the atmosphere and internal surfaces of the lunar excursion module were contaminated by lunar dust which was brought in on articles passed through the airlock. Consequently, the need exists for device or appliance to remove lunar dust from surfaces of material objects used outside of the proposed lunar habitat. Additionally, several concepts were investigated for preventing the accumulation of lunar dust on mechanisms and finished surfaces. The character of the dust and the lunar environment present unique challenges for the removal of contamination from exposed surfaces. In addition to a study of lunar dust adhesion properties, the project examines the use of various energy domains for removing the dust from exposed surfaces. Also, prevention alternatives are examined for systems exposed to lunar dust. A concept utilizing a pressurized gas is presented for dust removal outside of an atmospherically controlled environment. The concept consists of a small astronaut/robotic compatible device which removes dust from contaminated surfaces by a small burst of gas.

Links between Patagonian Ice Sheet fluctuations and Antarctic dust variability during the last glacial period (MIS 4-2)

NASA Astrophysics Data System (ADS)

Kaiser, Jérôme; Lamy, Frank

2010-06-01

Antarctic and Greenland ice-core records reveal large fluctuations of dust input on both orbital and millennial time-scales with potential global climate implications. At least during glacial periods, the Antarctic dust fluctuations appear to be largely controlled by environmental changes in southern South America. We compare dust flux records from two Antarctic ice-cores to variations in the composition of the terrigenous supply at ODP Site 1233 located off southern Chile and known to record fluctuations in the extent of the northern part of the Patagonian ice-sheet (NPIS) during the last glacial period (Marine Isotope Stage, MIS, 4 to 2). Within age uncertainties, millennial-scale glacial advances (retreats) of the NPIS correlate to Antarctic dust maxima (minima). In turn, NPIS fluctuations were closely related to offshore sea surface temperature (SST) changes. This pattern suggests a causal link involving changes in temperature, in rock flour availability, in latitudinal extensions of the westerly winds and in foehn winds in the southern Pampas and Patagonia. We further suggest that the long-term trend of dust accumulation is partly linked to the sea-level related changes in the size if the Patagonian source area due to the particular morphology of the Argentine shelf. We suggest that sea-level drops at the beginning of MIS 4 and MIS 2 were important for long-term dust increases, while changes in the Patagonian dust source regions primarily control the early dust decrease during the MIS 4/3 transition and Termination 1.

Exposure to field vs. storage wheat dust: different consequences on respiratory symptoms and immune response among grain workers.

PubMed

Barrera, Coralie; Wild, Pascal; Dorribo, Victor; Savova-Bianchi, Dessislava; Laboissière, Audrey; Pralong, Jacques A; Danuser, Brigitta; Krief, Peggy; Millon, Laurence; Reboux, Gabriel; Niculita-Hirzel, Hélène

2018-05-26

The aim of this study was to understand the differential acute effects of two distinct wheat-related dusts, such as field or stored wheat dust handling, on workers' health and how those effects evolved at 6 month intervals. Exposure, work-related symptoms, changes in lung function, and blood samples of 81 workers handling wheat and 61 controls were collected during the high exposure season and 6 months after. Specific IgG, IgE, and precipitins against 12 fungi isolated from wheat dust were titrated by enzyme-linked immunosorbent assay, dissociation-enhanced lanthanide fluorescence immunoassay, and electrosyneresis. The level of fungi was determined in the workers' environment. Levels of exhaled fraction of nitrogen monoxide (F E NO) and total IgE were obtained. Exposure response associations were investigated by mixed logistic and linear regression models. The recent exposure to field wheat dust was associated with a higher prevalence for five of six self-reported airway symptoms and with a lower F E NO than those in the control population. Exposure to stored wheat dust was only associated with cough. No acute impact of exposure on respiratory function was observed. Exposure to field wheat dust led to workers' sensitization against the three field fungi Aureobasidum, Cryptococcus, and Phoma, although exposure to storage wheat dust was associated with tolerance. The level of Ig remained stable 6 months after exposure. The clinical picture of workers exposed to field or storage wheat dust differed. The systematic characterization of the aerosol microbial profile may help to understand the reasons for those differences.

Variable features on Mars - Preliminary Mariner 9 television results.

NASA Technical Reports Server (NTRS)

Sagan, C.; Veverka, J.; Fox, P.; Dubisch, R.; Lederberg, J.; Levinthal, E.; Quam, L.; Tucker, R.; Pollack, J. B.; Smith, B. A.

1972-01-01

Systematic Mariner 9 photography of a range of Martian surface features, observed with all three photometric angles approximately invariant, reveals three general categories of albedo variations: (1) an essentially uniform contrast enhancement due to the dissipation of the dust storm; (2) the appearance of splotches, irregular dark markings at least partially related to topography; and (3) the development of both bright and dark linear streaks, generally emanating from craters. Some splotches and streaks vary on characteristic timescales of about two weeks; they have characteristic dimensions of kilometers to tens of kilometers. The morphology and variability of streaks and splotches, and the resolution of at least one splotch into an extensive dune system, implicate windblown dust as the principal agent of Martian albedo differences and variability.

Permissible Exposure Level for Lunar Dusts: Gaps are Closing

NASA Technical Reports Server (NTRS)

James, John T.; Lam, Chiu-Wing; Scully Robert; Santana, Patricia; Cooper, Bonnie; McKay, David; Zeidler-Erdely, Patti C.; Castranova, Vincent

2010-01-01

Space faring nations plan to return human explorers to the moon within the next decade. Experience during the Apollo flights suggests that lunar dust will invariably get into the habitat where the finest portion (less than 5 micrometers) could be inhaled by the crew before it is cleared from the atmosphere. NASA is developing a database from which a 6-month, episodic exposure standard for lunar dust can be set. Three kinds of moon dust were prepared from a parent sample of Apollo 14 regolith #14003,96. Our goal was to prepare each type of dust sample with a mean diameter less than 2 m, which is suitable for instillation into the lungs of rats. The three samples were prepared as follows: separation from the parent sample using a fluidized bed, grinding using a jet mill grinder, or grinding with a ball-mill grinder. Grinding simulated restoration of surface activation of dust expected to occur at the surface of the moon on native lunar dust. We used two grinding methods because they seemed to produce different modes of activation. The effects of grinding were preserved by maintaining the dust in ultra-pure nitrogen until immediately before it was placed in suspension for administration to rats. The dust was suspended in physiological saline with 10% Survanta, a lung surfactant. Rats were given intratrachael instillations of the dust suspension at three doses. In addition to the three moon dusts (A, C and E), we instilled the same amount of a negative control (TiO2, B) and a highly-toxic, positive control (quartz, D). These additional mineral dusts were selected because they have well-established and very different permissible exposure levels (PELs). Our goal was to determine where lunar dusts fit between these extremes, and then estimate a PEL for each lunar dust. We evaluated many indices of toxicity to the lung. The figure shows the changes in lactate dehydrogenase (LDH), a marker of cell death, for the five dusts. Benchmark dose software (Version 2.1.2) from the Environmental Protection Agency was used to estimate the 10% effect levels (BMD(sub 10)) using five models. The best-fitting model was used to estimate the optimal BMD(sub 10) (table)

Lyman alpha radiation in external galaxies

NASA Technical Reports Server (NTRS)

Neufeld, David A.; Mckee, Christopher F.

1990-01-01

The Ly alpha line of atomic hydrogen is often a luminous component of the radiation emitted by distant galaxies. Except for those galaxies which have a substantial central source of non-stellar ionizing radiation, most of the Ly alpha radiation emitted by galaxies is generated within regions of the interstellar medium which are photoionized by starlight. Conversely, much of the energy radiated by photoionized regions is carried by the Ly alpha line. Only hot, massive stars are capable of ionizing hydrogen in the interstellar medium which surrounds them, and because such stars are necessarily short-lived, Ly alpha emission traces regions of active star formation. Researchers argue that the strength of the Ly alpha emission observed from external galaxies may be used to estimate quantitatively the dust content of the emitting region, while the Ly alpha line profile is sensitive to the presence of shock waves. Interstellar dust particles and shock waves are intimately associated with the process of star formation in two senses. First, both dust particles and shock waves owe their existence to stellar activity; second, they may both serve as agents which facilitate the formation of stars, shocks by triggering gravitational instabilities in the interstellar gas that they compress, and dust by shielding star-forming molecular clouds from the ionizing and dissociative effects of external UV radiation. By using Ly alpha observations as a probe of the dust content in diffuse gas at high redshift, we might hope to learn about the earliest epochs of star formation.

Pentoxifylline does not alter the response to inhaled grain dust.

PubMed

Jagielo, P J; Watt, J L; Quinn, T J; Knapp, H R; Schwartz, D A

1997-05-01

Pentoxifylline (PTX) has been shown to reduce sepsis-induced neutrophil sequestration in the lung and inhibit endotoxin-mediated release of tumor necrosis factor-alpha (TNF-alpha). Previously, we have shown that endotoxin appears to be the principal agent in grain dust causing airway inflammation and airflow obstruction following grain dust inhalation. To determine whether PTX affects the physiologic and inflammatory events following acute grain dust inhalation, 10 healthy, nonsmoking subjects with normal airway reactivity were treated with PTX or placebo (PL) followed by corn dust extract (CDE) inhalation (0.08 mL/kg), using a single-blinded, crossover design. Subjects received PTX (1,200 mg/d) or PL for 4 days prior to CDE inhalation and 400 mg PTX or PL on the exposure day. Both respiratory symptoms and declines in FEV1 and FVC occurred following CDE exposure in both groups, but there were no significant differences in the frequency of symptoms or percent declines from baseline in the FEV1 and FVC at any of the time points measured in the study. Elevations in peripheral blood leukocyte and neutrophil concentrations and BAL total cell, neutrophil, TNF-alpha, and interleukin-8 concentrations were measured 4 h following exposure to CDE in both the PTX- and PL-treated subjects, but no significant differences were found between treatment groups. These results suggest that pretreatment with PTX prior to inhalation of CDE, in the doses used in this study, does not alter the acute physiologic or inflammatory events following exposure to inhaled CDE.

Airborne Dust in Space Vehicles and Habitats

NASA Technical Reports Server (NTRS)

James, John

2006-01-01

Airborne dust, suspended inside a space vehicle or in future celestial habitats, can present a serious threat to crew health if it is not controlled. During the Apollo missions to the moon, lunar dust brought inside the capsule caused eye irritation and breathing difficulty to the crew when they launched from the moon and re-acquired "microgravity." During Shuttle flights reactive and toxic dusts such as lithium hydroxide have created a risk to crew health, and fine particles from combustion events can be especially worrisome. Under nominal spaceflight conditions, airborne dusts and particles tend to be larger than on earth because of the absence of gravity settling. Aboard the ISS, dusts are effectively managed by HEPA filters, although floating dust in newly-arrived modules can be a nuisance. Future missions to the moon and to Mars will present additional challenges because of the possibility that external dust will enter the breathing atmosphere of the habitat and reach the crew's respiratory system. Testing with simulated lunar and Martian dust has shown that these materials are toxic when placed into the lungs of test animals. Defining and evaluating the physical and chemical properties of Martian dusts through robotic missions will challenge our ability to prepare better dust simulants and to determine the risk to crew health from exposure to such dusts.

Dust trap formation in a non-self-sustained discharge with external gas ionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filippov, A. V., E-mail: fav@triniti.ru; Babichev, V. N.; Pal’, A. F.

2015-11-15

Results from numerical studies of a non-self-sustained gas discharge containing micrometer dust grains are presented. The non-self-sustained discharge (NSSD) was controlled by a stationary fast electron beam. The numerical model of an NSSD is based on the diffusion drift approximation for electrons and ions and self-consistently takes into account the influence of the dust component on the electron and ion densities. The dust component is described by the balance equation for the number of dust grains and the equation of motion for dust grains with allowance for the Stokes force, gravity force, and electric force in the cathode sheath. Themore » interaction between dust grains is described in the self-consistent field approximation. The height of dust grain levitation over the cathode is determined and compared with experimental results. It is established that, at a given gas ionization rate and given applied voltage, there is a critical dust grain size above which the levitation condition in the cathode sheath cannot be satisfied. Simulations performed for the dust component consisting of dust grains of two different sizes shows that such grains levitate at different heights, i.e., size separation of dust drains levitating in the cathode sheath of an NSSD takes place.« less

Determinants of dust exposure in tunnel construction work.

PubMed

Bakke, Berit; Stewart, Patricia; Eduard, Wijnand

2002-11-01

In tunnel construction work, dust is generated from rock drilling, rock bolting, grinding, scaling, and transport operations. Other important dust-generating activities are blasting rock and spraying wet concrete on tunnel walls for strength and finishing work. The aim of this study was to identify determinants of dust exposure in tunnel construction work and to propose control measures. Personal exposures to total dust, respirable dust, and alpha-quartz were measured among 209 construction workers who were divided into 8 job groups performing similar tasks: drill and blast workers, shaft drilling workers, tunnel boring machine workers, shotcreting operators, support workers, concrete workers, outdoor concrete workers, and electricians. Information on determinants was obtained from interviewing the workers, observation by the industrial hygienist responsible for the sampling, and the job site superintendent. Multivariate regression models were used to identify determinants associated with the dust exposures within the job groups. The geometric mean exposure to total dust, respirable dust, and alpha-quartz for all tunnel workers was 3.5 mg/m(3) (GSD = 2.6), 1.2 mg/m(3) (GSD = 2.4), and 0.035 mg/m(3) (GSD = 5.0), respectively. A total of 15 percent of the total dust measurements, 5 percent of the respirable dust, and 21 percent of the alpha-quartz exceeded the Norwegian OELs of 10 mg/m(3), 5 mg/m(3), and 0.1 mg/m(3), respectively. Job groups with highest geometric mean total dust exposure were shotcreting operators (6.8 mg/m(3)), tunnel boring machine workers (6.2 mg/m(3)), and shaft drilling workers (6.1 mg/m(3)). The lowest exposed groups to total dust were outdoor concrete workers (1.0 mg/m(3)), electricians (1.4 mg/m(3)), and support workers (1.9 mg/m(3)). Important determinants of exposure were job group, job site, certain tasks (e.g., drilling and scaling), the presence of a cab, and breakthrough of the tunnel. The use of ventilated, closed cabs appeared to be the single most important control measure for lowering exposures.

Characterizing Particle Size Distributions of Crystalline Silica in Gold Mine Dust

PubMed Central

Chubb, Lauren G.; Cauda, Emanuele G.

2017-01-01

Dust containing crystalline silica is common in mining environments in the U.S. and around the world. The exposure to respirable crystalline silica remains an important occupational issue and it can lead to the development of silicosis and other respiratory diseases. Little has been done with regard to the characterization of the crystalline silica content of specific particle sizes of mine-generated dust. Such characterization could improve monitoring techniques and control technologies for crystalline silica, decreasing worker exposure to silica and preventing future incidence of silicosis. Three gold mine dust samples were aerosolized in a laboratory chamber. Particle size-specific samples were collected for gravimetric analysis and for quantification of silica using the Microorifice Uniform Deposit Impactor (MOUDI). Dust size distributions were characterized via aerodynamic and scanning mobility particle sizers (APS, SMPS) and gravimetrically via the MOUDI. Silica size distributions were constructed using gravimetric data from the MOUDI and proportional silica content corresponding to each size range of particles collected by the MOUDI, as determined via X-ray diffraction and infrared spectroscopic quantification of silica. Results indicate that silica does not comprise a uniform proportion of total dust across all particle sizes and that the size distributions of a given dust and its silica component are similar but not equivalent. Additional research characterizing the silica content of dusts from a variety of mine types and other occupational environments is necessary in order to ascertain trends that could be beneficial in developing better monitoring and control strategies. PMID:28217139

Assessing exposure risk for dust storm events-associated lung function decrement in asthmatics and implications for control

NASA Astrophysics Data System (ADS)

Hsieh, Nan-Hung; Liao, Chung-Min

2013-04-01

Asian dust storms (ADS) events are seasonally-based meteorological phenomena that exacerbate chronic respiratory diseases. The purpose of this study was to assess human health risk from airborne dust exposure during ADS events in Taiwan. A probabilistic risk assessment framework was developed based on exposure and experimental data to quantify ADS events induced lung function decrement. The study reanalyzed experimental data from aerosol challenge in asthmatic individuals to construct the dose-response relationship between inhaled dust aerosol dose and decreasing percentage of forced expiratory volume in 1 s (%FEV1). An empirical lung deposition model was used to predict deposition fraction for size specific dust aerosols in pulmonary regions. The toxicokinetic and toxicodynamic models were used to simulate dust aerosols binding kinetics in lung airway in that %FEV1 change was also predicted. The mask respirators were applied to control the inhaled dose under dust aerosols exposure. Our results found that only 2% probability the mild ADS events were likely to cause %FEV1 decrement higher than 5%. There were 50% probability of decreasing %FEV1 exceeding 16.9, 18.9, and 7.1% in north, center, and south Taiwan under severe ADS events, respectively. Our result implicates that the use of activated carbon of mask respirators has the best efficacy for reducing inhaled dust aerosol dose, by which the %FEV1 decrement can be reduced up to less than 1%.

Domestic exposure to endotoxin and respiratory morbidity in former smokers with COPD

PubMed Central

Bose, S; Rivera-Mariani, F; Chen, R; Williams, D; Belli, A; Aloe, C; McCormack, MC; Breysse, PN; Hansel, NN

2016-01-01

Indoor air pollution has been linked to adverse COPD health, but specific causative agents have not yet been identified. We evaluated the role of indoor endotoxin exposure upon respiratory health in former smokers with COPD. Eighty-four adults with moderate to severe COPD were followed longitudinally and indoor air and dust samples collected at baseline, 3 and 6 months. Respiratory outcomes were repeatedly assessed at each time point. The associations between endotoxin exposure in air and settled dust and health outcomes were explored using generalizing estimating equations in multivariate models accounting for confounders. Dust endotoxin concentrations in the main living area were highest in spring and lowest in fall, while airborne endotoxins remained steady across seasons. Airborne and dust endotoxin concentrations were weakly correlated with one another (rs=+0.24, p = 0.005). Endotoxin concentrations were not significantly associated with respiratory symptoms, rescue medication use, quality of life, or severe exacerbations. In-vitro whole blood assays of the pro-inflammatory capacity of PM10 filters with and without endotoxin depletion demonstrated that the endotoxin component of indoor air pollution was not the primary trigger for IL-1β release Our findings support that endotoxin is not the major driver in the adverse effects of indoor PM upon COPD morbidity. PMID:26547489

The concentrations of phthalates in settled dust in Bulgarian homes in relation to building characteristic and cleaning habits in the family

NASA Astrophysics Data System (ADS)

Kolarik, Barbara; Bornehag, Carl-Gustaf; Naydenov, Kiril; Sundell, Jan; Stavova, Petra; Nielsen, Ole Faurskov

Phthalate esters are chemical compounds with a broad range of applications. Recently, we have shown that significantly higher dust concentration of di(2-ethylhexyl) phthalate (DEHP) was found in Bulgarian homes of children with asthma or allergies compared to healthy children. The concentration of DEHP was found to be significantly associated with wheezing in the last 12 months as reported by parents. The objective of the current study was to examine the associations between concentrations of phthalates in settled dust collected in Bulgarian homes and building characteristics and cleaning habits. Dust samples from the child's bedroom were collected in 177 homes and analysed for the content of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), butyl benzyl phthalate (BBzP), di- n-octyl phthalate (DnOP) and DEHP. Information on building characteristics and family habits were collected from parental reports in questionnaires and from inspectors' observations in the homes. Significantly higher concentrations of BBzP, DEHP and DnOP in indoor dust were found in homes where polishing agents were used, compared to homes where such products were not used. The highest concentrations of DEHP, BBzP and DnOP were found in homes with the combination of a low frequency of dusting and the use of polish. There was no difference in phthalate concentrations between inspector-observed balatum flooring (PVC or linoleum) and wood flooring as well as between PVC, as determined by Raman spectra, and wood flooring. However, in a sub-group of homes with no use of polish, the concentration of DEHP was higher in homes with inspector-observed balatum compared with wood flooring but the difference was not significant may be due to a too small sample size.

Respiratory disease associated with occupational inhalation to hop (Humulus lupulus) during harvest and processing.

PubMed

Reeb-Whitaker, Carolyn K; Bonauto, David K

2014-11-01

There is little published evidence for occupational respiratory disease caused by hop dust inhalation. In the United States, hops are commercially produced in the Pacific Northwest region. To describe occupational respiratory disease in hop workers. Washington State workers' compensation claims filed by hop workers for respiratory disease were systematically identified and reviewed. Incidence rates of respiratory disease in hop workers were compared with rates in field vegetable crop farm workers. Fifty-seven cases of respiratory disease associated with hop dust inhalation were reported from 1995 to 2011. Most cases (61%) were diagnosed by the attending health care practitioner as having work-related asthma. Seven percent of cases were diagnosed as chronic obstructive pulmonary disease, and the remaining cases were diagnosed as allergic respiratory disorders (eg, allergic rhinitis) or asthma-associated symptoms (eg, dyspnea). Cases were associated with hop harvesting, secondary hop processing, and indirect exposure. The incidence rate of respiratory disease in hop workers was 15 cases per 10,000 full-time workers, which was 30 times greater than the incidence rate for field vegetable crop workers. A strong temporal association between hop dust exposure and respiratory symptoms and a clear association between an increase in hop dust concentrations and the clinical onset of symptoms were apparent in 3 cases. Occupational exposure to hop dust is associated with respiratory disease. Respiratory disease rates were higher in hop workers than in a comparison group of agricultural workers. Additional research is needed before hop dust can be confirmed as a causative agent for occupational asthma. Copyright © 2014 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Doped hydrophobic silica nano- and micro-particles as novel agents for developing latent fingerprints.

PubMed

Theaker, Brenden J; Hudson, Katherine E; Rowell, Frederick J

2008-01-15

Novel hydrophobic silica based particles have been developed to visualise latent fingerprints. The composition of the particles has been designed to maximise both hydrophobic and ionic interactions between a variety of coloured and fluorescent reporter molecules and the silicate backbone within the particles. The resulting doped particles retain the incorporated dyes with high affinity. In addition, a variety of sub-particles have also been embedded to again produce coloured or magnetisable hydrophobic particles. The particles can be harvested as nanoparticles or microparticles. The former are applied to latent fingerprints as an aqueous suspension and the latter as a dusting agent using brushes or a magnetic wand. Examples of the prints produced using these agents are given. The resulting prints have good definition.

Changing sources of strontium to soils and ecosystems across the Hawaiian Islands

USGS Publications Warehouse

Chadwick, O.A.; Derry, L.A.; Bern, C.R.; Vitousek, P.M.

2009-01-01

Strontium isotope ratios assist ecosystem scientists in constraining the sources of alkaline earth elements, but their interpretation can be difficult because of complexities in mineral weathering and in the geographical and environmental controls on elemental additions and losses. Hawaii is a "natural laboratory" where a number of important biogeochemical variables have either limited ranges or vary in systematic ways, providing a unique opportunity to understand the impact of time, climate, and atmospheric inputs on the evolution of base cation sources to ecosystems. There are three major sources of strontium (Sr) to these ecosystems, each with distinct isotopic compositions: basalt lava, Asian dust, and rainfall. We present Sr isotope and concentration data on both bulk soil digests and NH4Ac extracts from soil profiles covering a wide range of environments and substrate ages. Bulk soil material from dry climates and/or young substrate ages with > 80????g g- 1 Sr retain basalt-like Sr isotopic signatures, whereas those with Sr concentrations < 80????g g- 1 can have isotope signatures that range from basalt-like values to the more radiogenic values associated with continental dust. Although both dust accumulation and lava weathering are time- and rainfall-dependent, the overall concentration of Sr drops with increasing leaching even as quartz and mica derived from continental dust sources increase to > 40% by mass. At elevated dust levels, lava-derived Sr is low and dust-derived Sr is the dominant control of 87Sr/86Sr in bulk soils; however, 87Sr/86Sr of NH4Ac-extractable Sr largely reflects atmospheric deposition of marine aerosol in these situations. Overall, whole-soil Sr isotope values are controlled by complex interactions between Sr provided by lava weathering but partially lost by leaching, and Sr provided by dust but held in more resistant minerals. The isotopic composition of NH4Ac-extractable Sr and of the biota is controlled by lava weathering and rainfall contribution of Sr with only minor contributions from radiogenic dust sources. ?? 2009 Elsevier B.V.

Associations between self-reported pest treatments and pesticide concentrations in carpet dust.

PubMed

Deziel, Nicole C; Colt, Joanne S; Kent, Erin E; Gunier, Robert B; Reynolds, Peggy; Booth, Benjamin; Metayer, Catherine; Ward, Mary H

2015-03-25

Recent meta-analyses demonstrate an association between self-reported residential pesticide use and childhood leukemia risk. Self-reports may suffer from recall bias and provide information only on broad pesticide categories. We compared parental self-reported home and garden pest treatments to pesticides measured in carpet dust. Parents of 277 children with leukemia and 306 controls in Northern and Central California (2001-2007) were asked about insect and weed treatments during the previous year. Carpet dust samples were analyzed for 47 pesticides. We present results for the 7 insecticides (carbaryl, propoxur, chlorpyrifos, diazinon, cyfluthrin, cypermethrin, permethrin), 5 herbicides (2,4-dichlorophenoxyacetic acid [2,4-D], chlorthal, dicamba, mecoprop, simazine), and 1 synergist (piperonyl butoxide) that were present in home and garden products during the study period and were detected in ≥25% of carpet dust samples. We constructed linear regression models for the relative change in pesticide concentrations associated with self-reported treatment of pest types in cases and controls separately and combined, adjusting for demographics, housing characteristics, and nearby agricultural pesticide applications. Several self-reported treatments were associated with pesticide concentrations in dust. For example, households with flea/tick treatments had 2.3 (95% Confidence Interval [CI]: 1.4, 3.7) times higher permethrin concentrations than households not reporting this treatment. Households reporting treatment for ants/cockroaches had 2.5 (95% CI: 1.5, 4.2) times higher cypermethrin levels than households not reporting this treatment. Weed treatment by a household member was associated with 1.9 (1.4, 2.6), 2.2 (1.6, 3.1), and 2.8 (2.1, 3.7) times higher dust concentrations of dicamba, mecoprop, and 2,4-D, respectively. Weed treatments by professional applicators were null/inversely associated with herbicide concentrations in dust. Associations were generally similar between cases and controls and were consistent with pesticide active ingredients in these products during the study time period. Consistency between self-reported pest treatments, concentrations in dust, and pesticides in products lends credibility to the exposure assessment methods and suggests that differential recall by case-control status is minimal.

In vitro assessment of genotoxic effects of electric arc furnace dust on human lymphocytes using the alkaline comet assay.

PubMed

Garaj-Vrhovac, Vera; Orescanin, Visnja; Ruk, Damir; Gajski, Goran

2009-02-15

In vitro genotoxic effects of leachates of electric arc furnace dust (EAFD) on human peripheral lymphocytes, assessed prior and following the treatment with a strong alkaline solution were investigated using the alkaline comet assay. Prior and following the treatment, lymphocytes were incubated with leachate of EAFD for 6 and 24 hours at 37 degrees C. Negative controls were also included. Mean values of the tail lengths established in the samples treated with the leachate stemming from the original dust for 6 and 24 hours, were 15.70 microm and 16.78 microm, respectively, as compared to 12.33 microm found in the control sample. Slight, but significant increase in the tail length was also found with the dust treated with a strong alkaline solution (13.37 microm and 13.60 microm). In case of high heavy metal concentrations (the extract of the original furnace dust), the incubation period was revealed to be of significance as well. The obtained results lead to the conclusion that alkaline comet assay could be used as a rapid, sensitive and low-cost tool when assessing genotoxicity of various waste materials, such as leachates of the electric arc furnace dust.

Respiratory effects among rubberwood furniture factory workers in Thailand.

PubMed

Sriproed, Salakjit; Osiri, Pramuk; Sujirarat, Dusit; Chantanakul, Suttinun; Harncharoen, Kitiphong; Ong-artborirak, Parichat; Woskie, Susan R

2013-01-01

Respiratory symptoms and pulmonary function were examined among 89 rubberwood furniture factory workers. Acute and chronic irritant symptoms were assessed, lung function was measured both pre- and post-shift and personal inhalable dust exposure determined. The only symptoms with a significant increase among high dust level-exposed workers (>1 mg/m(3)) were those related to nasal irritation. High dust level-exposed workers had a significant cross-shift decrease in forced expiratory volume in 1 second/forced vital capacity (FEV(1)/FVC) compared with low dust level-exposed workers and increases in inhalable dust concentration levels (mg/m(3)) were significantly associated with decreases in the peak expiratory flow (PEF) across the work shift. For percent predicted pulmonary function levels, a significant decrement in PEF was found for high versus low rubberwood dust level-exposed workers, after controlling for confounders. These findings suggest the need for an occupational standard for rubberwood dust in Thailand.

Airway responsiveness to methacholine, respiratory symptoms, and dust exposure levels in grain and flour mill workers in eastern France.

PubMed

Massin, N; Bohadana, A B; Wild, P; Kolopp-Sarda, M N; Toamain, J P

1995-06-01

Our goal was to assess the relation between dust exposure levels and the respiratory health status of workers in grain and flour mills in eastern France. We studied 118 male workers from 11 mills and 164 unexposed male controls. Dust concentration was measured by personal sampling methods. Outcome variables included respiratory symptoms, routine pulmonary function tests, and indices of airway responsiveness to methacholine. A great within- and between-area variability of inhalable dust concentration was found in all mills. A dose-response relationship was observed between dust exposure levels and chronic respiratory symptoms, suggesting that exposure to grain and flour dust may lead to chronic bronchitis. A significant relation was found between dust exposure and airway hyper-responsiveness; this finding is important since it has been hypothesized that the latter abnormality may lead to or be a predisposing factor in subsequent chronic, irreversible airflow obstruction.

[Effects of Loquat-Branch Dust Substitution on Ganoderma lucidum Cultivation in Its Main Active Components].

PubMed

Zhang, Ping; Chen, Feng; Lai, Teng-qiang; Jin, Ling-yun; Li, Ye

2015-12-01

To select the best Ganoderma lucidum cultivation medium of replacing sawdust into loquat-branch dust, in order to realize high output and high quality production of Ganoderma lucidum. Loquat-branch dust was added as substitution in Ganoderma lucidum cultivation, its effects on the biomass and the content of Ganoderma polysaccharides, triterpenoids and flavonoids were analyzed. By using loquat-branch dust in culture, Ganoderma lucidum grew well with normal fruiting body obtained and spores released. Compared with control group, the biological efficiency was increased by 11.34%, when the addition of the loquat-branch dust was 80%, while the amount of spore had little difference. When the addition of the loquat-branch dust was 90%, the content of Ganoderma polysaccharides and triterpenoids was increased by 32.29% and 30.58% respectively, while the efficiency of flavonoids had little difference. Using loquat-branch dust cultivation can improve the quality of Ganoderma lucidum. According to the comprehensive score, 80% loquat-branch dust is the most suitable cultivation medium.

Testing of a Plasmadynamic Hypervelocity Dust Accelerator

NASA Astrophysics Data System (ADS)

Ticos, Catalin M.; Wang, Zhehui; Dorf, Leonid A.; Wurden, G. A.

2006-10-01

A plasmadynamic accelerator for microparticles (or dust grains) has been designed, built and tested at Los Alamos National laboratory. The dust grains are expected to be accelerated to hypervelocities on the order of 1-30 km/s, depending on their size. The key components of the plasmadynamic accelerator are a coaxial plasma gun operated at 10 kV, a dust dispenser activated by a piezoelectric transducer, and power and remote-control systems. The coaxial plasma gun produces a high density (10^18 cm-3) and low temperature (˜ 1 eV) plasma in deuterium ejected by J x B forces, which provides drag on the dust particles in its path. Carbon dust particles will be used, with diameters from 1 to 50 μm. The plasma parameters produced in the coaxial gun are presented and their implication to dust acceleration is discussed. High speed dust will be injected in the National Spherical Torus Experiment to measure the pitch angle of magnetic field lines.

Regional and climatic controls on seasonal dust deposition in the southwestern U.S.

USGS Publications Warehouse

Reheis, M.C.; Urban, F.E.

2011-01-01

Vertical dust deposition rates (dust flux) are a complex response to the interaction of seasonal precipitation, wind, changes in plant cover and land use, dust source type, and local vs. distant dust emission in the southwestern U.S. Seasonal dust flux in the Mojave-southern Great Basin (MSGB) deserts, measured from 1999 to 2008, is similar in summer-fall and winter-spring, and antecedent precipitation tends to suppress dust flux in winter-spring. In contrast, dust flux in the eastern Colorado Plateau (ECP) region is much larger in summer-fall than in winter-spring, and twice as large as in the MSGB. ECP dust is related to wind speed, and in the winter-spring to antecedent moisture. Higher summer dust flux in the ECP is likely due to gustier winds and runoff during monsoonal storms when temperature is also higher. Source types in the MSGB and land use in the ECP have important effects on seasonal dust flux. In the MSGB, wet playas produce salt-rich dust during wetter seasons, whereas antecedent and current moisture suppress dust emission from alluvial and dry-playa sources during winter-spring. In the ECP under drought conditions, dust flux at a grazed-and-plowed site increased greatly, and also increased at three annualized, previously grazed sites. Dust fluxes remained relatively consistent at ungrazed and currently grazed sites that have maintained perennial vegetation cover. Under predicted scenarios of future climate change, these results suggest that an increase in summer storms may increase dust flux in both areas, but resultant effects will depend on source type, land use, and vegetation cover. ?? 2011.

Effect of Organic Dust Exposure on Pulmonary Functions in Workers of Vegetable Market with Special Reference to its Microbial Content.

PubMed

Goel, Arun; Omar, Balram Ji; Kathrotia, Rajesh; Patil, Prashant M; Mittal, Sunita

2018-01-01

Wholesale vegetable market is a rich source of generation of organic dust as loads of fruits and vegetables are loaded and unloaded here daily. Thus, regular workers are exposed to this organic dust for a considerable period of time depending on their work schedule. This study was planned to determine the microbial status of organic dust and to explore its association with pulmonary functions in the workers of wholesale vegetable market in Rishikesh. It was a cross-sectional exploratory/observational study. Thirty-five apparently healthy adult males were selected from vegetable market having no history of any chronic illness. Smokers and alcoholic were excluded from the study. The same number of age- and sex-matched controls with the same exclusion criteria were recruited from workers not working in the vegetable market and also not exposed to any other kinds of organic dust. Microbial culture of air in the vegetable market was done. It was compared with the microbial status of air in the working place of controls. Pulmonary functions of all the workers were performed with the help of digital spirometer (Helios 401). Bacterial and fungal concentration was found to be significantly higher in the air of vegetable market as compared to air in the workplace of controls (such as coagulase-negative staphylococci >25 colony-forming unit (CFU) at incubation temperature vs. 10-12 CFU at incubation temperature, significant growth of Mucor , Aspergillus niger , and Candida nonalbicans in vegetable market as compared to workplace of controls). Pulmonary function parameters (percentage forced expiratory volume in 1 st s (FEV 1 ), percentage predicted forced expiratory flow in mid-half of expiration, and FEV 1 ) of workers exposed to organic dust in vegetable market were also significantly lower ( P < 0.05). Exposure of organic dust is associated with compromised pulmonary functions and there is a need of formulation of safety guidelines.

Standoff detection of chemical and biological threats using laser-induced breakdown spectroscopy.

PubMed

Gottfried, Jennifer L; De Lucia, Frank C; Munson, Chase A; Miziolek, Andrzej W

2008-04-01

Laser-induced breakdown spectroscopy (LIBS) is a promising technique for real-time chemical and biological warfare agent detection in the field. We have demonstrated the detection and discrimination of the biological warfare agent surrogates Bacillus subtilis (BG) (2% false negatives, 0% false positives) and ovalbumin (0% false negatives, 1% false positives) at 20 meters using standoff laser-induced breakdown spectroscopy (ST-LIBS) and linear correlation. Unknown interferent samples (not included in the model), samples on different substrates, and mixtures of BG and Arizona road dust have been classified with reasonable success using partial least squares discriminant analysis (PLS-DA). A few of the samples tested such as the soot (not included in the model) and the 25% BG:75% dust mixture resulted in a significant number of false positives or false negatives, respectively. Our preliminary results indicate that while LIBS is able to discriminate biomaterials with similar elemental compositions at standoff distances based on differences in key intensity ratios, further work is needed to reduce the number of false positives/negatives by refining the PLS-DA model to include a sufficient range of material classes and carefully selecting a detection threshold. In addition, we have demonstrated that LIBS can distinguish five different organophosphate nerve agent simulants at 20 meters, despite their similar stoichiometric formulas. Finally, a combined PLS-DA model for chemical, biological, and explosives detection using a single ST-LIBS sensor has been developed in order to demonstrate the potential of standoff LIBS for universal hazardous materials detection.

Dust-concentration measurement based on Mie scattering of a laser beam

PubMed Central

Yu, Xiaoyu; Shi, Yunbo; Wang, Tian; Sun, Xu

2017-01-01

To realize automatic measurement of the concentration of dust particles in the air, a theory for dust concentration measurement was developed, and a system was designed to implement the dust concentration measurement method based on laser scattering. In the study, the principle of dust concentration detection using laser scattering is studied, and the detection basis of Mie scattering theory is determined. Through simulation, the influence of the incident laser wavelength, dust particle diameter, and refractive index of dust particles on the scattered light intensity distribution are obtained for determining the scattered light intensity curves of single suspended dust particles under different characteristic parameters. A genetic algorithm was used to study the inverse particle size distribution, and the reliability of the measurement system design is proven theoretically. The dust concentration detection system, which includes a laser system, computer circuitry, air flow system, and control system, was then implemented according to the parameters obtained from the theoretical analysis. The performance of the designed system was evaluated. Experimental results show that the system performance was stable and reliable, resulting in high-precision automatic dust concentration measurement with strong anti-interference ability. PMID:28767662

Evaluation of a Dust Control for a Small Slab-Riding Dowel Drill for Concrete Pavement

PubMed Central

Echt, Alan; Mead, Kenneth

2016-01-01

Purpose To assess the effectiveness of local exhaust ventilation to control respirable crystalline silica exposures to acceptable levels during concrete dowel drilling. Approach Personal breathing zone samples for respirable dust and crystalline silica were collected while laborers drilled holes 3.5 cm diameter by 36 cm deep in a concrete slab using a single-drill slab-riding dowel drill equipped with local exhaust ventilation. Data were collected on air flow, weather, and productivity. Results All respirable dust samples were below the 90 µg detection limit which, when combined with the largest sample volume, resulted in a minimum detectable concentration of 0.31 mg m−3. This occurred in a 32-min sample collected when 27 holes were drilled. Quartz was only detected in one air sample; 0.09 mg m−3 of quartz was found on an 8-min sample collected during a drill maintenance task. The minimum detectable concentration for quartz in personal air samples collected while drilling was performed was 0.02 mg m−3. The average number of holes drilled during each drilling sample was 23. Over the course of the 2-day study, air flow measured at the dust collector decreased from 2.2 to 1.7 m3 s−1. Conclusions The dust control performed well under the conditions of this test. The initial duct velocity with a clean filter was sufficient to prevent settling, but gradually fell below the recommended value to prevent dust from settling in the duct. The practice of raising the drill between each hole may have prevented the dust from settling in the duct. A slightly higher flow rate and an improved duct design would prevent settling without regard to the position of the drill. PMID:26826033

Evaluation of a Dust Control for a Small Slab-Riding Dowel Drill for Concrete Pavement.

PubMed

Echt, Alan; Mead, Kenneth

2016-05-01

To assess the effectiveness of local exhaust ventilation to control respirable crystalline silica exposures to acceptable levels during concrete dowel drilling. Personal breathing zone samples for respirable dust and crystalline silica were collected while laborers drilled holes 3.5 cm diameter by 36 cm deep in a concrete slab using a single-drill slab-riding dowel drill equipped with local exhaust ventilation. Data were collected on air flow, weather, and productivity. All respirable dust samples were below the 90 µg detection limit which, when combined with the largest sample volume, resulted in a minimum detectable concentration of 0.31 mg m(-3). This occurred in a 32-min sample collected when 27 holes were drilled. Quartz was only detected in one air sample; 0.09 mg m(-3) of quartz was found on an 8-min sample collected during a drill maintenance task. The minimum detectable concentration for quartz in personal air samples collected while drilling was performed was 0.02 mg m(-3). The average number of holes drilled during each drilling sample was 23. Over the course of the 2-day study, air flow measured at the dust collector decreased from 2.2 to 1.7 m(3) s(-1). The dust control performed well under the conditions of this test. The initial duct velocity with a clean filter was sufficient to prevent settling, but gradually fell below the recommended value to prevent dust from settling in the duct. The practice of raising the drill between each hole may have prevented the dust from settling in the duct. A slightly higher flow rate and an improved duct design would prevent settling without regard to the position of the drill. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2016.

A STUDY OF FISCHER 344 RATS EXPOSED TO SILICA DUST FOR SIX MONTHS AT CONCENTRATIONS OF 0, 2, 10 OR 20 MG / M3.

DOE Office of Scientific and Technical Information (OSTI.GOV)

KUTZMAN,R.S.

1984-02-01

The major objective of this study was to relate the results of a series of functional tests to the compositional and structural alterations in the rat lung induced by subchronic exposure to silica dust. Fischer-344 rats were exposed for 6 hours/day, 5 days/week for 6 months to either 0, 2, 10, or 20 mg SiO{sub 2}/m{sup 3}. The general appearance of the exposed rats was not different from that of the controls. Interestingly, female rats exposed to silica dust, at all tested concentrations, gained more weight than the controls. The lung weight and the lung-to-body weight ratio was greater inmore » the male rats exposed to the highest concentration of silica dust.« less

Instituting a filtration/pressurization system to reduce dust concentrations in a control room at a mineral processing plant

PubMed Central

Noll, J.; Cecala, A.; Hummer, J.

2016-01-01

The National Institute for Occupational Safety and Health has observed that many control rooms and operator compartments in the U.S. mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room that had no cleaning system for intake air, a filtration and pressurization system originally designed for enclosed cabs was modified and installed. This system was composed of two filtering units: one to filter outside air and one to filter and recirculate the air inside the control room. Eighty-seven percent of submicrometer particles were reduced by the system under static conditions. This means that greater than 87 percent of respirable dust particles should be reduced as the particle-size distribution of respirable dust particles is greater than that of submicrometer particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced, which is an important component of an effective system and minimizes the entry of particles, such as dust, into the room. The intake airflow was around 118 cfm, greater than the airflow suggested by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for acceptable indoor air quality. After one year, the loading of the filter caused the airflow to decrease to 80 cfm, which still produces acceptable indoor air quality. Due to the loading of the filters, the reduction efficiency for submicrometer particles under static conditions increased to 94 percent from 87 percent. PMID:26834293

Systematic on-site monitoring of compliance dust samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grayson, R.L.; Gandy, J.R.

1996-12-31

Maintaining compliance with U.S. respirable coal mine dust standards can be difficult on high-productivity longwall panels. Comprehensive and systematic analysis of compliance dust sample data, coupled with access to the U.S. Bureau of Mines (USBM) DUSTPRO, can yield important information for use in maintaining compliance. The objective of this study was to develop and apply a customized software for the collection, storage, modification, and analysis of respirable dust data while providing for flexible export of data and linking with the USBM`s expert advisory system on dust control. An executable, IBM-compatible software was created and customized for use by the personmore » in charge of collecting, submitting, analyzing, and monitoring respirable dust compliance samples. Both descriptive statistics and multiple regression analysis were incorporated. The software allows ASCH files to be exported and directly links with DUSTPRO. After development and validation of the software, longwall compliance data from two different mines was analyzed to evaluate the value of the software. Data included variables on respirable dust concentration, tons produced, the existence of roof/floor rock (dummy variable), and the sampling cycle (dummy variables). Because of confidentiality, specific data will not be presented, only the equations and ANOVA tables. The final regression models explained 83.8% and 61.1% of the variation in the data for the two panels. Important correlations among variables within sampling cycles showed the value of using dummy variables for sampling cycles. The software proved flexible and fast for its intended use. The insights obtained from use improved the systematic monitoring of respirable dust compliance data, especially for pinpointing the most effective dust control methods during specific sampling cycles.« less

Undisturbed dust as a metric of long-term indoor insecticide exposure: Residential DDT contamination from indoor residual spraying and its association with serum levels in the VHEMBE cohort.

PubMed

Gaspar, Fraser W; Chevrier, Jonathan; Bornman, Riana; Crause, Madelein; Obida, Muvhulawa; Barr, Dana Boyd; Bradman, Asa; Bouwman, Henk; Eskenazi, Brenda

2015-12-01

Although approximately 123 million people may be exposed to high levels of insecticides through the use of indoor residual spraying (IRS) for malaria control, few studies exist on indoor insecticide contamination due to IRS and its relationship with human exposure. In the present study, we developed a sampling method to collect undisturbed dust from 50 homes in Limpopo, South Africa, a region where dichlorodiphenyltrichloroethane (DDT) has been used in IRS programs to prevent malaria for ~70years. We quantified DDT and its degradation products, dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyldichloroethane (DDD) in dust samples to determine dust loading levels and compared these levels to paired serum concentrations of p,p'-DDT and p,p'-DDE in women residents. p,p'-DDT and p,p'-DDE had the highest detection frequencies in both dust (58% and 34% detection, respectively) and serum samples (98% and 100% detection, respectively). Significantly higher detection frequencies for o,p'-DDT, p,p'-DDE, and p,p'-DDD were observed in dust samples collected in buildings that had been previously sprayed for malaria control. We also observed a significant, positive association between dust loading and serum concentrations of p,p'-DDT and p,p'-DDE (Spearman's rho=0.68 and 0.54, respectively). Despite the low detection frequency in dust, our results indicate that undisturbed dust may be a good metric to quantify long-term home exposure to DDT-related compounds and that contamination of the home environment may be an important determinant/source of DDT and DDE exposure. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Electrostatic Environments of Mars and the Moon

NASA Technical Reports Server (NTRS)

Calle, Carlos I.

2011-01-01

The electrical activity present in the environment near the surfaces of Mars and the moon has very different origins and presents a challenge to manned and robotic planetary exploration missions. Mars is covered with a layer of dust that has been redistributed throughout the entire planet by global dust storms. Dust, levitated by these storms as well as by the frequent dust devils, is expected to be electrostatically charged due to the multiple grain collisions in the dust-laden atmosphere. Dust covering the surface of the moon is expected to be electrostatically charged due to the solar wind, cosmic rays, and the solar radiation itself through the photoelectric effect. Electrostatically charged dust has a large tendency to adhere to surfaces. NASA's Mars exploration rovers have shown that atmospheric dust falling on solar panels can decrease their efficiency to the point of rendering the rover unusable. And as the Apollo missions to the moon showed, lunar dust adhesion can hinder manned and unmanned lunar exploration activities. Taking advantage of the electrical activity on both planetary system bodies, dust removal technologies are now being developed that use electrostatic and dielectrophoretic forces to produce controlled dust motion. This paper presents a short review of the theoretical and semiempirical models that have been developed for the lunar and Martian electrical environments.

Reduction of airborne radioactive dust by means of a charged water spray.

PubMed

Bigu, J; Grenier, M G

1989-07-01

An electrostatic precipitator based on charged water spray technology has been used in an underground uranium mine to control long-lived radioactive dust and short-lived aerosol concentration in a mine gallery where dust from a rock breaking/ore transportation operation was discharged. Two main sampling stations were established: one upstream of the dust precipitator and one downstream. In addition, dust samplers were placed at different locations between the dust discharge and the end of the mine gallery. Long-lived radioactive dust was measured using cascade impactors and nylon cyclone dust samplers, and measurement of the radioactivity on the samples was carried out by conventional methods. Radon and thoron progeny were estimated using standard techniques. Experiments were conducted under a variety of airflow conditions. A maximum radioactive dust reduction of about 40% (approximately 20% caused by gravitational settling) at a ventilation rate of 0.61 m3/sec was obtained as a result of the combined action of water scrubbing and electrostatic precipitation by the charged water spray electrostatic precipitator. This represents the optimum efficiency attained within the range of ventilation rates investigated. The dust reduction efficiency of the charged water spray decreased with increasing ventilation rate, i.e., decreasing air residence time, and hence, reduced dust cloud/charged water droplets mixing time.

Urban dust in the Guanzhong basin of China, part II: A case study of urban dust pollution using the WRF-Dust model.

PubMed

Li, Nan; Long, Xin; Tie, Xuexi; Cao, Junji; Huang, Rujin; Zhang, Rong; Feng, Tian; Liu, Suixin; Li, Guohui

2016-01-15

We developed a regional dust dynamical model (WRF-Dust) to simulate surface dust concentrations in the Guanzhong (GZ) basin of China during two typical dust cases (19th Aug. and 26th Nov., 2013), and compared model results with the surface measurements at 17 urban and rural sites. The important improvement of the model is to employ multiple high-resolution (0.5-500 m) remote sensing data to construct dust sources. The new data include the geographic information of constructions, croplands, and barrens over the GZ basin in summer and winter of 2013. For the first time, detailed construction dust emissions have been introduced in a regional dust model in large cities of China. Our results show that by including the detailed dust sources, model performance at simulating dust pollutions in the GZ basin is significantly improved. For example, the simulated dust concentration average for the 17 sites increases from 28 μg m(-3) to 59 μg m(-3), closing to the measured concentration of 66 μg m(-3). In addition, the correlation coefficient (r) between the calculated and measured dust concentrations is also improved from 0.17 to 0.57, suggesting that our model better presents the spatial variation. Further analysis shows that urban construction activities are the crucial source in controlling urban dust pollutions. It should be considered by policy makers for mitigating particulate air pollution in many Chinese cities. Copyright © 2015 Elsevier B.V. All rights reserved.

Research of vibration controlling based on programmable logic controller for electrostatic precipitator

NASA Astrophysics Data System (ADS)

Zhang, Zisheng; Li, Yanhu; Li, Jiaojiao; Liu, Zhiqiang; Li, Qing

2013-03-01

In order to improve the reliability, stability and automation of electrostatic precipitator, circuits of vibration motor for ESP and vibration control ladder diagram program are investigated using Schneider PLC with high performance and programming software of Twidosoft. Operational results show that after adopting PLC, vibration motor can run automatically; compared with traditional control system of vibration based on single-chip microcomputer, it has higher reliability, better stability and higher dust removal rate, when dust emission concentrations <= 50 mg m-3, providing a new method for vibration controlling of ESP.

Transfer of termiticidal dust compounds and their effects on symbiotic protozoa of Reticulitermes flavipes (Kollar)

Treesearch

Frederick Green; Rachel A. Arango; Glenn R. Esenther

2008-01-01

Dusting of termites in situ has been used as a control measure for decades; however environmental awareness of the toxicity of certain compounds now limits their use (eg arsenical dusts). Our laboratory is in the process of suppressing an isolated colony of Reticulitermes flavipes (Kollar) from a small village of 250 homes in mid-central Wisconsin (Endeavor, WI)....

[Health survey of plant workers for an occupational exposure to ammonium perchlorate].

PubMed

Chen, Hong-xia; Shao, Yuan-peng; Wu, Feng-hong; Li, Yang-ping; Peng, Kai-liang

2013-01-01

To understand the occupational hazards of ammonium perchlorate dust on operating workers and to provide the basis preventive measures for protecting the workers' health. 36 workers exposed to ammonium perchlorate dust and 48 unexposed workers from one factory were selected as the exposure and control groups. Investigations on the general condition, sampling of dust in the workplaces and a special medical examination were conducted for two groups, including occupational history, clinical manifestations, blood routine test, hepatic and renal functions, indexes of thyroid hormone, spirometric test and chest X-ray. The total dust concentration of AP in the batch plant reached to 51.63 ± 43.27 mg/m(3), exceeding the U.S. Occupational Safety and Health Administration (OSHA) permission exposure limits. The systolic blood pressure in the exposure group was higher than that of the control group (146.14 ± 21.03 VS 134.67 ± 18.58), and the difference was statistically significant (P < 0.05). The detection rates of the cumulative total symptoms, short of breath and skin itch symptoms in the exposure group were significantly higher than those in the control group (86.11% VS 66.67%; 30.56% VS 12.50%) (P < 0.05), respectively. FT(3) level in the exposure group significantly lowered than the control group, and the difference was statistically significant (P < 0.01); The pulmonary function result showed that FEV1/FVC% in the exposure group was lower than that in the control group (106.50 ± 28.99 VS 111.70 ± 19.72), but the difference was not significant. X-ray examination revealed one case of pulmonary X-ray abnormalities in the exposure group, diagnosis of pneumoconiosis, and one case with about 1.0 × 1.0 small nodules detected on the left of lung door area in the control group. The systolic blood pressure of workers in the exposure group was significantly higher, which could not exclude related to the exposure to AP dust; The T(3) levels in the exposure workers were lower than those in the control group, which may due to AP exposure, suggesting that long-term chronic exposure to AP dust may affect thyroid function.

Silica exposure, silicosis, and lung cancer: a necropsy study.

PubMed Central

Hessel, P A; Sluis-Cremer, G K; Hnizdo, E

1990-01-01

Recent studies of the association between lung cancer and silicosis and silica dust have been inconclusive; some showing positive association and some showing none. The present study matched 231 cases of lung cancer with 318 controls by year of birth. Subjects were selected from the necropsy records of the National Centre for Occupational Health. Data on intensity and duration of exposure to silica dust were obtained from personnel records. Presence or absence of lung cancer and the presence and severity of silicosis of the parenchyma, pleura, and hilar glands were documented from necropsy reports. Smoking data were abstracted from records of routine examinations. No case-control differences were noted for any of the exposure indicators including cumulative dust exposure, total dusty shifts, weighted average intensity of exposure, total underground shifts, and shifts in high dust. Similarly, no association was found between lung cancer and the presence or severity of silicosis and any site. Stratified analyses showed neither significant nor suggestive trends when case-control comparisons for silicosis were examined by level of dust exposure or smoking. Reasons for disparity between these results and those of some other studies may include concomitant exposures to radon daughters, asbestos, diesel emissions, and cigarette smoking; idiosyncracies of the compensation process; and the possibility of a threshold in the relation(s). PMID:2155648

Managing Stormwater and Dust at Demolition Sites

EPA Pesticide Factsheets

Learn how to manage stormwater and dust at demolition sites, including developing a stormwater solution prevention plan, best practices for erosion, runoff and sediment control to reduce environmental impacts and comply with environmental regulations.

Generation rate and particle size distribution of wood dust by handheld sanding operation.

PubMed

Ojima, Jun

2016-11-29

The International Agency for Research on Cancer (IARC) and Japan Society for Occupational Health (JSOH) classified wood dust as a human carcinogen. Former studies have suggested that sanding with a portable sander is one of the processes that are liable to cause highest exposure to wood dust. However, the wood dust by sanding operation has not been investigated sufficiently. In this study, the generation rate and the particle size distribution of the wood dust produced by handheld sanding operation were observed by laboratory experiments. Beech and cypress were taken as typical hard and soft wood specimen respectively, and sanded with a portable sander. Three grades of sand paper (coarse, medium, fine) were attached to the sander in turn to be tested. The quantity of the wood dust produced by the sander was measured by weighing the specimen before and after the sanding and then the generation rate of the dust was calculated. Soft wood generated more dust than hard wood due to the difference in abrasion durability. A coarse sand paper produced more dust than a fine sand paper. The particles of less than 1 μm diameter were scarcely observed in the wood dust. When the specimens were sanded with a fine sand paper, the mass median aerodynamic diameters of beech dust and cypress dust were 9.0 μm and 9.8 μm, respectively. Respirable wood dust is able to be controlled by general ventilation with more than 0.7-4.2 m 3 /min ventilation rate.

Time-dependent modeling of dust injection in semi-detached ITER divertor plasma

NASA Astrophysics Data System (ADS)

Smirnov, Roman; Krasheninnikov, Sergei

2017-10-01

At present, it is generally understood that dust related issues will play important role in operation of the next step fusion devices, i.e. ITER, and in the development of future fusion reactors. Recent progress in research on dust in magnetic fusion devises has outlined several topics of particular concern: a) degradation of fusion plasma performance; b) impairment of in-vessel diagnostic instruments; and c) safety issues related to dust reactivity and tritium retention. In addition, observed dust events in fusion edge plasmas are highly irregular and require consideration of temporal evolution of both the dust and the fusion plasma. In order to address the dust-related fusion performance issues, we have coupled the dust transport code DUSTT and the edge plasma transport code UEDGE in time-dependent manner, allowing modeling of transient dust-induced phenomena in fusion edge plasmas. Using the coupled codes we simulate burst-like injection of tungsten dust into ITER divertor plasma in semi-detached regime, which is considered as preferable ITER divertor operational mode based on the plasma and heat load control restrictions. Analysis of transport of the dust and the dust-produced impurities, and of dynamics of the ITER divertor and edge plasma in response to the dust injection will be presented. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, under Award Number DE-FG02-06ER54852.

Examination of redirected continuous miner scrubber discharge configurations for exhaust face ventilation systems

PubMed Central

Organiscak, J.A.; Beck, T.W.

2015-01-01

The U.S. National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) has recently studied several redirected scrubber discharge configurations in its full-scale continuous miner gallery for both dust and gas control when using an exhaust face ventilation system. Dust and gas measurements around the continuous mining machine in the laboratory showed that the conventional scrubber discharge directed outby the face with a 12.2-m (40-ft) exhaust curtain setback appeared to be one of the better configurations for controlling dust and gas. Redirecting all the air toward the face equally up both sides of the machine increased the dust and gas concentrations around the machine. When all of the air was redirected toward the face on the off-curtain side of the machine, gas accumulations tended to be reduced at the face, at the expense of increased dust levels in the return and on the curtain side of the mining machine. A 6.1-m (20-ft) exhaust curtain setback without the scrubber operating resulted in the lowest dust levels around the continuous mining machine, but this configuration resulted in some of the highest levels of dust in the return and gas on the off-curtain side of the mining face. Two field studies showed some similarities to the laboratory findings, with elevated dust levels at the rear corners of the continuous miner when all of the scrubber exhaust was redirected toward the face either up the off-tubing side or equally up both sides of the mining machine. PMID:26251566

Physiological traits and antioxidant metabolism of leaves of tropical woody species challenged with cement dust.

PubMed

Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Lemos-Filho, José Pires de; Modolo, Luzia Valentina; Paiva, Elder Antonio Sousa

2017-10-01

Tropical woody species occurring in limestone outcrops are frequently exposed to particulate material from cement factories. The effects of 60-day cement dust exposure on physiological traits and enzymatic antioxidant system of young plant leaves of Guazuma ulmifolia Lam., Myracrodruon urundeuva Allemão and Trichilia hirta L. were investigated. Cement dust (2.5 or 5mgcm -2 ) was applied to the leaf surface or soil or both (leaf plus soil) and plants were maintained at greenhouse. Cement dust barely affected the mineral nutrient levels, except for iron whose content was decreased in leaves/leaflets of all species studied. The incident light was partly blocked in cement dust-treated leaves, regardless of the plant species, causing a decrease in the photosynthetic pigments in M. urundeuva. The chlorophyll b content, however, increased in G. ulmifolia and T. hirta leaves upon cement dust treatment. The potential quantum yield of photosystem II in challenged leaves of G. ulmifolia was 3.8% lower than that of control plants, while such trait remained unaffected in the leaves of the other species. No changes in leaf stomatal conductance and antioxidant enzymes activities were observed, except for M. urundeuva, which experienced a 31% increment in the superoxide dismutase activity upon 5mgcm -2 cement dust (leaf plus soil treatment), when compared with control plants. Overall, the mild changes caused by cement dust in the in physiological and biochemical traits of the species studied indicate that such species might be eligible for further studies of revegetation in fields impacted by cement factories. Copyright © 2017 Elsevier Inc. All rights reserved.

Laboratory Investigation of Space and Planetary Dust Grains

NASA Technical Reports Server (NTRS)

Spann, James

2005-01-01

Dust in space is ubiquitous and impacts diverse observed phenomena in various ways. Understanding the dominant mechanisms that control dust grain properties and its impact on surrounding environments is basic to improving our understanding observed processes at work in space. There is a substantial body of work on the theory and modeling of dust in space and dusty plasmas. To substantiate and validate theory and models, laboratory investigations and space borne observations have been conducted. Laboratory investigations are largely confined to an assembly of dust grains immersed in a plasma environment. Frequently the behaviors of these complex dusty plasmas in the laboratory have raised more questions than verified theories. Space borne observations have helped us characterize planetary environments. The complex behavior of dust grains in space indicates the need to understand the microphysics of individual grains immersed in a plasma or space environment.

Investigation of fugitive dust emissions from nepheline syenite mine tailings near Nephton, Ontario

NASA Astrophysics Data System (ADS)

Ogungbemide, Damilare Immanuel

A set of experiments was designed to investigate the factors--atmospheric and surficial--controlling fugitive dust emissions from the tailings ponds of UNIMIN Canada, a mining company that extracts and produces nepheline syenite (feldspar) at two adjacent sites (Nephton and Blue Mountain) located north of Havelock, Ontario. Using wind tunnel measurements, the combined influence of relative humidity and temperature (represented by the absolute matric potential, |psi|) on dust emission was quantified and modeled. About 300 experimental runs were conducted under various conditions of wind speed (4.5-6.25 ms -1), temperature (0-30°C) and relative humidity (10-70%). Generally, dust flux decreased as a logarithmic function of matric potential, with dust emission strongly suppressed for RH > 60% or |psi|<70 MPa. Field measurements also confirmed the role of relative humidity in suppressing dust emission. Irrigation, which is widely used by mines to control dust emissions, reduced ambient dust concentration at the study site only about 60% of the time, with the highest mitigation efficiencies (average of 90%) occurring when the total depth of water applied intermittently over a few hours was greater than 10 mm. In the absence of emergent vegetation, the terrestrial laser scanning (TLS) technique proved to be a promising method for detecting and estimating both spatial and temporal moisture content changes in the field environment, particularly for the very thin surface layer, which is the most important layer for dust emission. It is hoped that the results from this study will help mines to optimize their dust management programs for the range of climate and topographic conditions found at their sites, and also serve as a source of useful information and input data for atmospheric dispersion models, such as AERMOD and CALPUFF, whose accuracy depends on the quality of the input data such as the emission rate.

Laboratory Studies of the Optical Properties and Condensation Processes of Cosmic Dust Grains

NASA Technical Reports Server (NTRS)

Abbas, M. M.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; West, E.; Sheldon, R.; Witherow, W. K.; Gallagher, D. L.; Adrian, M. L.

2002-01-01

A laboratory facility for conducting a variety of experiments on single isolated dust particles of astrophysical interest levitated in an electrodynamics balance has been developed at NASA/Marshall Space Flight Center. The objective of the research is to employ this experimental technique for studies of the physical and optical properties of individual cosmic dust grains of 0.1-100 micron size in controlled pressure/temperatures environments simulating astrophysical conditions. The physical and optical properties of the analogs of interstellar and interplanetary dust grains of known composition and size distribution will be investigated by this facility. In particular, we will carry out three classes of experiments to study the micro-physics of cosmic dust grains. (1) Charge characteristics of micron size single dust grains to determine the photoelectric efficiencies, yields, and equilibrium potentials when exposed to UV radiation. (2) Infrared optical properties of dust particles (extinction coefficients and scattering phase functions) in the 1-30 micron region using infrared diode lasers and measuring the scattered radiation. (3) Condensation experiments to investigate the condensation of volatile gases on colder nucleated particles in dense interstellar clouds and lower planetary atmospheres. The condensation experiments will involve levitated nucleus dust grains of known composition and initial mass (or m/q ratio), cooled to a temperature and pressure (or scaled pressure) simulating the astrophysical conditions, and injection of a volatile gas at a higher temperature from a controlled port. The increase in the mass due to condensation on the particle will be monitored as a function of the dust particle temperature and the partial pressure of the injected volatile gas. The measured data will permit determination of the sticking coefficients of volatile gases and growth rates of dust particles of astrophysical interest. Some preliminary results based on measurements of photoelectric emission and radiation pressure on single isolated 0.2 to 6.6 micron size silica particles exposed to UV radiation at 120-200 nm and green laser light at 532 nm are presented.

House dust mites on skin, clothes, and bedding of atopic dermatitis patients.

PubMed

Teplitsky, Valery; Mumcuoglu, Kosta Y; Babai, Ilan; Dalal, Ilan; Cohen, Rifka; Tanay, Amir

2008-08-01

Atopic dermatitis is a common allergic condition in children, often associated with a positive skin reaction to house dust mite allergens. To determine the presence of house dust mites on the skin, clothes, and bedding of patients with atopic dermatitis. Nineteen patients with atopic dermatitis were examined during a 2-year period. Samples from affected and healthy skin surfaces were obtained with adhesive tape, and dust samples from bedding and clothes were collected with a vacuum cleaner at the start of the study and 3-6 weeks later, and examined for the presence of house dust mites. The findings were compared with those of 21 healthy controls. The most common mite species on skin were Dermatophagoides pteronyssinus and Dermatophagoides farinae, which were found in nine patients and three controls. The patient group showed a significantly larger percentage of samples with mites than did the control group (34.9% and 7.9%, respectively) (P < 0.001), and a significantly larger percentage of individuals with at least one positive sample (84.2% and 14.2%, respectively) (P < 0.0001). No correlation was found between the number of mites on the skin and clothes/bedding of patients, or between patients and controls with regard to the number of mites on the clothes and bedding. Patients with atopic dermatitis showed a higher prevalence of mites on their skin than did healthy individuals, which could be involved in allergic sensitization and disease exacerbation.

Air cleaning performance of a new environmentally controlled primary crusher operator booth.

PubMed

Organiscak, J A; Cecala, A B; Zimmer, J A; Holen, B; Baregi, J R

2016-02-01

The National Institute for Occupational Safety and Health (NIOSH) cooperated with 3M Company in the design and testing of a new environmentally controlled primary crusher operator booth at the company's Wausau granite quarry near Wausau, WI. This quarry had an older crusher booth without a central heating, ventilation and air conditioning (HVAC) system, and without an air filtration and pressurization system. A new replacement operator booth was designed and installed by 3M based on design considerations from past NIOSH research on enclosed cab filtration systems. NIOSH conducted pre-testing of the old booth and post-testing of the new booth to assess the new filtration and pressurization system's effectiveness in controlling airborne dusts and particulates. The booth's dust and particulate control effectiveness is described by its protection factor, expressed as a ratio of the outside to inside concentrations measured during testing. Results indicate that the old booth provided negligible airborne respirable dust protection and low particulate protection from the outside environment. The newly installed booth provided average respirable dust protection factors from 2 to 25 over five shifts of dust sampling with occasional worker ingress and egress from the booth, allowing some unfiltered contaminants to enter the enclosure. Shorter-term particle count testing outside and inside the booth under near-steady-state conditions, with no workers entering or exiting the booth, resulted in protection factors from 35 to 127 on 0.3- to 1.0-μm respirable size particulates under various HVAC airflow operating conditions.

Debilitating lung disease among surface coal miners with no underground mining tenure.

PubMed

Halldin, Cara N; Reed, William R; Joy, Gerald J; Colinet, Jay F; Rider, James P; Petsonk, Edward L; Abraham, Jerrold L; Wolfe, Anita L; Storey, Eileen; Laney, A Scott

2015-01-01

To characterize exposure histories and respiratory disease among surface coal miners identified with progressive massive fibrosis from a 2010 to 2011 pneumoconiosis survey. Job history, tenure, and radiograph interpretations were verified. Previous radiographs were reviewed when available. Telephone follow-up sought additional work and medical history information. Among eight miners who worked as drill operators or blasters for most of their tenure (median, 35.5 years), two reported poor dust control practices, working in visible dust clouds as recently as 2012. Chest radiographs progressed to progressive massive fibrosis in as few as 11 years. One miner's lung biopsy demonstrated fibrosis and interstitial accumulation of macrophages containing abundant silica, aluminum silicate, and titanium dust particles. Overexposure to respirable silica resulted in progressive massive fibrosis among current surface coal miners with no underground mining tenure. Inadequate dust control during drilling/blasting is likely an important etiologic factor.

Debilitating Lung Disease Among Surface Coal Miners With No Underground Mining Tenure

PubMed Central

Halldin, Cara N.; Reed, William R.; Joy, Gerald J.; Colinet, Jay F.; Rider, James P.; Petsonk, Edward L.; Abraham, Jerrold L.; Wolfe, Anita L.; Storey, Eileen; Laney, A. Scott

2015-01-01

Objective To characterize exposure histories and respiratory disease among surface coal miners identified with progressive massive fibrosis from a 2010 to 2011 pneumoconiosis survey. Methods Job history, tenure, and radiograph interpretations were verified. Previous radiographs were reviewed when available. Telephone follow-up sought additional work and medical history information. Results Among eight miners who worked as drill operators or blasters for most of their tenure (median, 35.5 years), two reported poor dust control practices, working in visible dust clouds as recently as 2012. Chest radiographs progressed to progressive massive fibrosis in as few as 11 years. One miner’s lung biopsy demonstrated fibrosis and interstitial accumulation of macrophages containing abundant silica, aluminum silicate, and titanium dust particles. Conclusions Overexposure to respirable silica resulted in progressive massive fibrosis among current surface coal miners with no underground mining tenure. Inadequate dust control during drilling/blasting is likely an important etiologic factor. PMID:25563541

Quantifying global dust devil occurrence from meteorological analyses

PubMed Central

Jemmett-Smith, Bradley C; Marsham, John H; Knippertz, Peter; Gilkeson, Carl A

2015-01-01

Dust devils and nonrotating dusty plumes are effective uplift mechanisms for fine particles, but their contribution to the global dust budget is uncertain. By applying known bulk thermodynamic criteria to European Centre for Medium-Range Weather Forecasts (ECMWF) operational analyses, we provide the first global hourly climatology of potential dust devil and dusty plume (PDDP) occurrence. In agreement with observations, activity is highest from late morning into the afternoon. Combining PDDP frequencies with dust source maps and typical emission values gives the best estimate of global contributions of 3.4% (uncertainty 0.9–31%), 1 order of magnitude lower than the only estimate previously published. Total global hours of dust uplift by dry convection are ∼0.002% of the dust-lifting winds resolved by ECMWF, consistent with dry convection making a small contribution to global uplift. Reducing uncertainty requires better knowledge of factors controlling PDDP occurrence, source regions, and dust fluxes induced by dry convection. Key Points Global potential dust devil occurrence quantified from meteorological analyses Climatology shows realistic diurnal cycle and geographical distribution Best estimate of global contribution of 3.4% is 10 times smaller than the previous estimate PMID:26681815

[Analysis and prevention of dust pollution caused by 5 common prosthetic materials].

PubMed

Yang, Xiang-Wen; Wei, Bin; Zhu, Cao-Yun; Qian, Liang; Li, Yi-Han

2017-10-01

To analyze and evaluate dust pollution in prosthodontic clinic and make proposal for reasonable protection. This study analyzed the particle size, element composition and dust concentration of 5 materials which were commonly used in dental restorations (veneering ceramics, cobalt-chromium alloy, photosensitive plastic, hard base resin, advanced artificial teeth) by using scanning electron microscopy (SEM), X-ray energy dispersive spectrometer（EDS） and dust concentration laser tester, in order to assess the effects of prosthodontic dust posed on medical staff health and put forward reasonable suggestions for prevention and control of dust pollution. The particle size of veneering ceramics, cobalt-chromium alloy, photosensitive plastic, hard base resin and advanced artificial teeth was (2.15±3.00), (33.78±24.33), (7.78±11.86), (31.16±44.35) and (28.45±39.21)μm, respectively. The time weighted average respirable dust concentration of veneering ceramics was 0.393 mg/m 2 which was beyond the scope of national security. Dust pollution is serious in prosthodontic clinic to which we should pay more attention and take appropriate prevention measures.

In-depth survey report: control technology for manual transfer of chemical powders at the B. F. Goodrich Company, Marietta, Ohio

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gressel, M.G.; Heitbrink, W.A.; McGlothlin, J.D.

1985-12-01

A field study was conducted in the B.F. Goodrich Industrial Plastics Division facility, Marietta, Ohio to evaluate sources of worker dust exposure at a ventilated booth used for the weigh out and transfer of powdered materials from large drums to small bags. The sources of dust exposure evaluated were: depth of scooping, clothing, worker anthropometry, work practices, biomechanics, and specific items in the job cycle. Dust exposure for workers wearing clean clothing was not significantly different from exposure for workers wearing dirty clothing. Depth of scooping from the drum significantly affected dust exposure. There appeared also to be a relationshipmore » between the size of the worker and dust exposure when scooping from the bottom of the drum. Work practices may also play a part. The authors conclude that, while the results showed abnormally high dust levels, all three workers studied wore respirable dust respirators during the experiment to protect them from these high levels. Air flow patterns at the booth suggest that the ventillation provided may even contributed to dust exposure.« less

Increased Levels of Markers of Microbial Exposure in Homes with Indoor Storage of Organic Household Waste

PubMed Central

Wouters, Inge M.; Douwes, Jeroen; Doekes, Gert; Thorne, Peter S.; Brunekreef, Bert; Heederik, Dick J. J.

2000-01-01

As part of environmental management policies in Europe, separate collection of organic household waste and nonorganic household waste has become increasingly common. As waste is often stored indoors, this policy might increase microbial exposure in the home environment. In this study we evaluated the association between indoor storage of organic waste and levels of microbial agents in house dust. The levels of bacterial endotoxins, mold β(1→3)-glucans, and fungal extracullar polysaccharides (EPS) of Aspergillus and Penicillium species were determined in house dust extracts as markers of microbial exposure. House dust samples were collected in 99 homes in The Netherlands selected on the basis of whether separated organic waste was present in the house. In homes in which separated organic waste was stored indoors for 1 week or more the levels of endotoxin, EPS, and glucan were 3.2-, 7.6-, and 4.6-fold higher, respectively (all P < 0.05), on both living room and kitchen floors than the levels in homes in which only nonorganic residual waste was stored indoors. Increased levels of endotoxin and EPS were observed, 2.6- and 2.1-fold (P < 0.1), respectively, when separated organic waste was stored indoors for 1 week or less, whereas storage of nonseparated waste indoors had no effect on microbial agent levels (P > 0.2). The presence of textile floor covering was another major determinant of microbial levels (P < 0.05). Our results indicate that increased microbial contaminant levels in homes are associated with indoor storage of separated organic waste. These increased levels might increase the risk of bioaerosol-related respiratory symptoms in susceptible people. PMID:10653727

Intensified dust storm activity and Valley fever infection in the southwestern United States

NASA Astrophysics Data System (ADS)

Tong, Daniel Q.; Wang, Julian X. L.; Gill, Thomas E.; Lei, Hang; Wang, Binyu

2017-05-01

Climate models have consistently projected a drying trend in the southwestern United States, aiding speculation of increasing dust storms in this region. Long-term climatology is essential to documenting the dust trend and its response to climate variability. We have reconstructed long-term dust climatology in the western United States, based on a comprehensive dust identification method and continuous aerosol observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. We report here direct evidence of rapid intensification of dust storm activity over American deserts in the past decades (1988-2011), in contrast to reported decreasing trends in Asia and Africa. The frequency of windblown dust storms has increased 240% from 1990s to 2000s. This dust trend is associated with large-scale variations of sea surface temperature in the Pacific Ocean, with the strongest correlation with the Pacific Decadal Oscillation. We further investigate the relationship between dust and Valley fever, a fast-rising infectious disease caused by inhaling soil-dwelling fungus (Coccidioides immitis and C. posadasii) in the southwestern United States. The frequency of dust storms is found to be correlated with Valley fever incidences, with a coefficient (r) comparable to or stronger than that with other factors believed to control the disease in two endemic centers (Maricopa and Pima County, Arizona).

Cytogenetic effects in workers occupationally exposed to tobacco dust.

PubMed

Umadevi, B; Swarna, M; Padmavathi, P; Jyothi, A; Reddy, P P

2003-03-03

Tobacco dust mainly contains nitrosamines, which are readily absorbed by the body tissues like skin, respiratory epithelium, and mucous membrane of mouth, nose and intestines. Exposure to tobacco dust is known to affect the respiratory tracts in humans. In the present study, cytogenetic effects of exposure to tobacco dust are evaluated in 154 male tobacco factory workers and 138 age and sex matched controls by analysing chromosomal aberrations in their peripheral blood lymphocytes. The workers were in the age group of 20-55 years and were employed in the tobacco processing factory for 1-32 years. Heparinised blood samples were collected from workers and control subjects and lymphocyte cultures were carried out by using standard technique. Slides were prepared and 150 metaphases were screened for each sample for various structural and numerical types of abnormalities. A statistically significant increase was observed in the frequencies of chromosomal aberrations in non-smoking and smoking exposed groups when compared to the respective controls. An increase in the frequencies of chromosomal aberrations was also observed with increase in years of service in the exposed subjects.

The Effect of Martian Dust on Radiator Performance

NASA Technical Reports Server (NTRS)

Hollingsworth, D. Keith; Witte, Larry C.; Hinke, Jaime; Hulbert, Kathryn

2004-01-01

Experiments were performed in which the effective emittance of three types of radiator Coatings was measured as Martian dust simulant was added to the radiator face. The apparatus consisted of multiple radiator coupons on which Carbondale Red Clay dust was deposited. The coupons were powered by electric heaters, using a guard-heating configuration to achieve the accuracy required for acceptable emittance calculations. The apparatus was containing in a vacuum chamber that featured a liquid-nitrogen cooled shroud that simulated the Martian sky temperature. Radiator temperatures ranged from 250 to 350 K with sky temperatures from 185 to 248 K. Results show that as dust was added to the radiator surfaces, the effective emittance of the high - emittance coatings decreased from near 0.9 to a value of about 0.5. A low-emittance control surface, polished aluminum, demonstrated a rise in effective emittance for thin dust layers, and then a decline as the dust layer thickened. This behavior is attributed to the conductive resistance caused by the dust layer.

Decay of Reactivity Induced by Simulated Solar Wind Implantation of a Forsteritic Olivine

NASA Technical Reports Server (NTRS)

Kuhlman, K.R.; Sridharan, K.; Garrison, D.H.; McKay, D.S.; Taylor, L.A.

2009-01-01

In returning humans to the Moon, the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) must address many problems faced by the original Apollo astronauts. Major among these is control of the fine dust (<20 microns) that makes up approx.20 wt% portion of the lunar surface. This ubiquitous, clinging, sharp, abrasive, glassy dust caused a plethora of problems with seals, abrasion, and coatings, in addition to possible health problems, including lunar dust hayfever. The lifetime of reactive sites on the surfaces of irradiated lunar dust grains is of interest to those studying human health because of the free radicals and toxic compounds that may be formed and may not passivate quickly when exposed to habitat/spacecraft air.

[Protecting Safety During Dust Fires and Dust Explosions - The Example of the Formosa Fun Coast Water Park Accident].

PubMed

Hsieh, Ming-Hong; Wu, Jia-Wun; Li, Ya-Cing; Tang, Jia-Suei; Hsieh, Chun-Chien

2016-02-01

This paper will explore the fire and explosion characteristics of cornstarch powder as well as strategies for protecting the safety of people who are involved a dust fire or dust explosion. We discuss the 5 elements of dust explosions and conduct tests to analyze the fire and explosion characteristics of differently colored powders (yellow, golden yellow, pink, purple, orange and green). The results show that, while all of the tested powders were difficult to ignite, low moisture content was associated with significantly greater risks of ignition and flame spread. We found the auto-ignition temperature (AIT) of air-borne cornstarch powder to be between 385°C and 405°C, with yellow-colored cornstarch powder showing the highest AIT and pink-colored cornstarch powder showing the lowest AIT. The volume resistivity of all powder samples was approximately 108 Ω.m, indicating that they were nonconductive. Lighters and cigarettes are effective ignition sources, as their lit temperatures are higher than the AIT of cornstarch powder. In order to better protect the safety of individuals at venues where cornstarch powder is released, explosion control measures such as explosion containment facilities, vents, and explosion suppression and isolation devices should be installed. Furthermore, employees that work at these venues should be better trained in explosion prevention and control measures. We hope this article is a reminder to the public to recognize the fire and explosion characteristics of flammable powders as well as the preventive and control measures for dust explosions.

Ceramic tiles with black pigment made from stainless steel plant dust: Physical properties and long-term leaching behavior of heavy metals.

PubMed

Zhu, Renbo; Ma, Guojun; Cai, Yongsheng; Chen, Yuxiang; Yang, Tong; Duan, Boyu; Xue, Zhengliang

2016-04-01

Stainless steel plant dust is a hazardous by-product of the stainless steelmaking industry. It contains large amounts of Fe, Cr, and Ni, and can be potentially recycled as a raw material of inorganic black pigment in the ceramic industry to reduce environmental contamination and produce value-added products. In this paper, ceramic tiles prepared with black pigment through recycling of stainless steel plant dust were characterized in terms of physical properties, such as bulk density, water absorption, apparent porosity, and volume shrinkage ratio, as well as the long-term leaching behavior of heavy metals (Cr, Ni, Pb, Cd, and Zn). The results show that good physical properties of ceramic tiles can be obtained with 8% pigments addition, sample preparation pressure of 25 MPa, and sintering at 1200 ºC for 30 min. The major controlling leaching mechanism for Cr and Pb from the ceramic tiles is initial surface wash-off, while the leaching behavior of Cd, Ni, and Zn from the stabilized product is mainly controlled by matrix diffusion. The reutilization process is safe and effective to immobilize the heavy metals in the stainless steel plant dust. Stainless steel plant dust is considered as a hazardous material, and it can be potentially recycled for black pigment preparation in the ceramic industry. This paper provides the characteristics of the ceramic tiles with black pigment through recycling stainless steel plant dust, and the long-term leaching behavior and controlling leaching mechanisms of heavy metals from the ceramic tile. The effectiveness of the treatment process is also evaluated.

Environmental factors controlling the seasonal variability in particle size distribution of modern Saharan dust deposited off Cape Blanc

NASA Astrophysics Data System (ADS)

Friese, Carmen A.; van der Does, Michèlle; Merkel, Ute; Iversen, Morten H.; Fischer, Gerhard; Stuut, Jan-Berend W.

2016-09-01

The particle sizes of Saharan dust in marine sediment core records have been used frequently as a proxy for trade-wind speed. However, there are still large uncertainties with respect to the seasonality of the particle sizes of deposited Saharan dust off northwestern Africa and the factors influencing this seasonality. We investigated a three-year time-series of grain-size data from two sediment-trap moorings off Cape Blanc, Mauritania and compared them to observed wind-speed and precipitation as well as satellite images. Our results indicate a clear seasonality in the grain-size distributions: during summer the modal grain sizes were generally larger and the sorting was generally less pronounced compared to the winter season. Gravitational settling was the major deposition process during winter. We conclude that the following two mechanisms control the modal grain size of the collected dust during summer: (1) wet deposition causes increased deposition fluxes resulting in coarser modal grain sizes and (2) the development of cold fronts favors the emission and transport of coarse particles off Cape Blanc. Individual dust-storm events throughout the year could be recognized in the traps as anomalously coarse-grained samples. During winter and spring, intense cyclonic dust-storm events in the dust-source region explained the enhanced emission and transport of a larger component of coarse particles off Cape Blanc. The outcome of our study provides important implications for climate modellers and paleo-climatologists.

Interactions Between Mineral Dust, Climate, and Ocean Ecosystems

NASA Technical Reports Server (NTRS)

Gasso, Santiago; Grassian, Vicki H.; Miller, Ron L.

2010-01-01

Over the past decade, technological improvements in the chemical and physical characterization of dust have provided insights into a number of phenomena that were previously unknown or poorly understood. In addition, models are now incorporating a wider range of physical processes, which will allow us to better quantify the climatic and ecological impacts of dust. For example, some models include the effect of dust on oceanic photosynthesis and thus on atmospheric CO 2 (Friedlingstein et al. 2006). The impact of long-range dust transport, with its multiple forcings and feedbacks, is a relatively new and complex area of research, where input from several disciplines is needed. So far, many of these effects have only been parameterized in models in very simple terms. For example, the representation of dust sources remains a major uncertainty in dust modeling and estimates of the global mass of airborne dust. This is a problem where Earth scientists could make an important contribution, by working with climate scientists to determine the type of environments in which easily erodible soil particles might have accumulated over time. Geologists could also help to identify the predominant mineralogical composition of dust sources, which is crucial for calculating the radiative and chemical effects of dust but is currently known for only a few regions. Understanding how climate and geological processes control source extent and characterizing the mineral content of airborne dust are two of the fascinating challenges in future dust research.

An index for estimating the potential metal pollution contribution to atmospheric particulate matter from road dust in Beijing.

PubMed

Zhao, Hongtao; Shao, Yaping; Yin, Chengqing; Jiang, Yan; Li, Xuyong

2016-04-15

The resuspension of road dust from street surfaces could be a big contributor to atmospheric particulate pollution in the rapid urbanization context in the world. However, to date what its potential contribution to the spatial pattern is little known. Here we developed an innovative index model called the road dust index (RI<105μm) and it combines source and transport factors for road dust particles <105μm in diameter. It could quantify and differentiate the impact of the spatial distribution of the potential risks posed by metals associated with road dust on atmospheric suspended particles. The factors were ranked and weighted based on road dust characteristics (the amounts, grain sizes, and mobilities of the road dust, and the concentrations and toxicities of metals in the road dust). We then applied the RI<105μm in the Beijing region to assess the spatial distribution of the potential risks posed by metals associated with road dust on atmospheric suspended particles. The results demonstrated that the road dust in urban areas has higher potential risk of metal to atmospheric particles than that in rural areas. The RI<105μm method offers a new and useful tool for assessing the potential risks posed by metals associated with road dust on atmospheric suspended particles and for controlling atmospheric particulate pollution caused by road dust emissions. Copyright © 2016 Elsevier B.V. All rights reserved.

Modeling the dust cycle from sand dunes to haboobs

NASA Astrophysics Data System (ADS)

Kallos, George; Patlakas, Platon; Bartsotas, Nikolaos; Spyrou, Christos; Qahtani, Jumaan Al; Alexiou, Ioannis; Bar, Ayman M.

2017-04-01

The dust cycle is a rather complicated mechanism depending on various factors. The most important factors affecting dust production is soil characteristics (soil composi-tion, physical and chemical properties, water content, temperature etc). The most known production mechanism at small scale is the saltation-bombardment. This mechanism is able to accurately predict uptake of dust particles up to about 10 μm. Larger dust particles are heavier and fall relatively fast due to the gravitational influ-ence. The other controlling factors of dust uptake and transport are wind speed (to be above a threshold) and turbulence. Weather conditions affecting dust produc-tion/transport/deposition are of multi-scale ranging from small surface inhomoge-neities to mesoscale and large-scale systems. While the typical dust transport mech-anism is related to wind conditions near the surface, larger scale systems play an important role on dust production. Such systems are associated with mesoscale phenomena typical of the specific regions. Usually they are associated with deep convection and strong downdrafts and are known as haboobs. Density currents are formed in the surface with strong winds and turbulence. Density currents can be considered as dust sources by themselves due to high productivity of dust. In this presentation we will discuss characteristics of the dust production mechanisms at multiscale over the Arabian Peninsula by utilizing the RAMS/ICLAMS multiscale model. A series of simulations at small-scale have been performed and mitigation actions will be explored.

Inactivation of dust mites, dust mite allergen, and mold from carpet.

PubMed

Ong, Kee-Hean; Lewis, Roger D; Dixit, Anupma; MacDonald, Maureen; Yang, Mingan; Qian, Zhengmin

2014-01-01

Carpet is known to be a reservoir for biological contaminants, such as dust mites, dust mite allergen, and mold, if it is not kept clean. The accumulation of these contaminants in carpet might trigger allergies or asthma symptoms in both children and adults. The purpose of this study is to compare methods for removal of dust mites, dust mite allergens, and mold from carpet. Carpets were artificially worn to simulate 1 to 2 years of wear in a four-person household. The worn carpets were inoculated together with a common indoor mold (Cladosporium species) and house dust mites and incubated for 6 weeks to allow time for dust mite growth on the carpet. The carpets were randomly assigned to one of the four treatment groups. Available treatment regimens for controlling carpet contaminants were evaluated through a literature review and experimentation. Four moderately low-hazard, nondestructive methods were selected as treatments: vacuuming, steam-vapor, Neem oil (a natural tree extract), and benzalkonium chloride (a quaternary ammonium compound). Steam vapor treatment demonstrated the greatest dust mite population reduction (p < 0.05) when compared to other methods. The two physical methods, steam vapor and vacuuming, have no statistically significant efficacy in inactivating dust mite allergens (p = 0.084), but have higher efficacy when compared to the chemical method on dust mite allergens (p = 0.002). There is no statistically significant difference in the efficacy for reducing mold in carpet (p > 0.05) for both physical and chemical methods. The steam-vapor treatment effectively killed dust mites and denatured dust mite allergen in the laboratory environment.

Ecological Restoration Programs Induced Amelioration of the Dust Pollution in North China Plain

NASA Astrophysics Data System (ADS)

Long, X.; Tie, X.; Li, G.; Junji, C.

2017-12-01

With Moderate Resolution Imaging Spectroradiometer (MODIS) land cover product (MCD12Q1), we quantitatively evaluate the ecological restoration programs (ERP) induced land cover change in China by calculating gridded the land use fraction (LUF). We clearly capture two obvious vegetation (grass and forest) protective barriers arise between the dust source region DSR and North China Plain NCP from 2011 to 2013. The WRF-DUST model is applied to investigate the impact of ERPs on dust pollution from 2 to 8 March 2016, corresponding to a national dust storm event over China. Despite some model biases, the WRF-DUST model reasonably reproduced the temporal variations of dust storm event, involving IOA of 0.96 and NMB of 2% for DSR, with IOA of 0.83 and NMB of -15% for downwind area of NCP. Generally, the WRF-DUST model well capture the spatial variations and evolutions of dust storm events with episode-average [PMC] correlation coefficient (R) of 0.77, especially the dust storm outbreak and transport evolution, involving daily average [PMC] R of 0.9 and 0.73 on 4-5 March, respectively. It is found that the ERPs generally reduce the dust pollution in NCP, especially for BTH, involving upper dust pollution control benefits of -15.3% (-21.0 μg m-3) for BTH, and -6.2% (-9.3 μg m-3) for NCP. We are the first to conduct model sensitivity studies to quantitatively evaluate the impacts of the ERPs on the dust pollution in NCP. And our narrative is independently based on first-hand sources, whereas government statistics.

Generation rate and particle size distribution of wood dust by handheld sanding operation

PubMed Central

Ojima, Jun

2016-01-01

Objectives: The International Agency for Research on Cancer (IARC) and Japan Society for Occupational Health (JSOH) classified wood dust as a human carcinogen. Former studies have suggested that sanding with a portable sander is one of the processes that are liable to cause highest exposure to wood dust. However, the wood dust by sanding operation has not been investigated sufficiently. In this study, the generation rate and the particle size distribution of the wood dust produced by handheld sanding operation were observed by laboratory experiments. Methods: Beech and cypress were taken as typical hard and soft wood specimen respectively, and sanded with a portable sander. Three grades of sand paper (coarse, medium, fine) were attached to the sander in turn to be tested. The quantity of the wood dust produced by the sander was measured by weighing the specimen before and after the sanding and then the generation rate of the dust was calculated. Results: Soft wood generated more dust than hard wood due to the difference in abrasion durability. A coarse sand paper produced more dust than a fine sand paper. The particles of less than 1 μm diameter were scarcely observed in the wood dust. When the specimens were sanded with a fine sand paper, the mass median aerodynamic diameters of beech dust and cypress dust were 9.0 μm and 9.8 μm, respectively. Conclusions: Respirable wood dust is able to be controlled by general ventilation with more than 0.7-4.2 m3/min ventilation rate. PMID:27725491

Laboratory Studies on the Charging of Dust Grains in a Plasma

NASA Astrophysics Data System (ADS)

Xu, Wenjun

1993-01-01

The charging of dust grains by the surrounding plasma is studied in a dusty plasma device (DPD) (Xu, W., B. Song, R. L. Merlino, and N. D'Angelo, Rev. Sci. Instrum., 63, 5266, 1992). The dusty plasma device consists of a rotating-drum dust dispersal device used in conjunction with an existing Q-machine, to produce extended, steady state, magnetized plasma columns. The dust density in the dust chamber is controlled by the drum rotation speed. The device is capable of generating a dusty plasma in which as much as about 90% of the negative charge is attached to the dust grains of 1-10mu m size. Measurements of the dust parameter eta, the percentage of negative charge on free electrons in the dusty plasma, are presented. The dust parameter eta is found to depend on the rotational speed of the dust chamber, plasma density and the type and size of different dust. The dust parameter eta is calculated from a pair of Langmuir curves taken with and without dust under the same conditions. The operation of the dust chamber as described above has been confirmed by the agreement between the measurements of eta and the direct mechanical measurements consisting of weighing dust samples collected within the rotation dust chamber, at different rotation rates. By varying the ratio d/lambda_ {rm D} between the intergrain distance and the plasma Debye length, the effects predicted by Goertz and Ip (Goertz, C. K., and W-H. Ip, Geophys. Res. Lett., 11, 349, 1984), and subsequently reanalyzed in a more general fashion by Whipple et al. (Whipple, E. C., T. G. Northrop, and D. A. Mendis, J. Geophys. Rev., 90, 7405, 1985), as "isolated" dust grains become "closely packed" grains, have been demonstrated experimentally (Xu, W., N. D'Angelo, and R. L. Merlino, J. Geophys. Rev., 98, 7843, 1993). Similar results are presented and compared for two types of dust, kaolin and Al_2O _3, which have been studied in the experiment.

Identification of potential hazards associated with new residential construction.

PubMed

Methner, M M

2000-02-01

There were several advantages and limitations of this observational study. The most important advantage of this study was the opportunity to observe residential construction workers performing their jobs. By observing work practices, valuable information was gathered about specific trades and their potential exposure to various chemical and physical agents. This information will be useful in guiding subsequent exposure assessments. Probably the greatest limitation of this study was the lack of participation by homebuilders. Ideally, observations of construction processes would have been more objective if the study included the participation of more than one homebuilder. Aside from one worker who was observed to wear safety glasses, leather gloves, and a dust mask, virtually no personal protective equipment (PPE) was observed onsite. Often small contractors do not have the financial resources necessary to procure the appropriate PPE and issue these items to the workers. Based on hazard prevalence, professional judgement, and the degree of hazardous product use, potential exposures that warrant quantitative sampling efforts during Phase 2 of this study are: bulldozer/backhoe operators--noise, vibration, diesel exhaust; concrete workers--naphtha, mineral spirits, Portland cement; asphalt workers--petroleum hydrocarbons, asphalt, mineral spirits; plumbers--methylethyl ketone, acetone, tetrahydrofuran, cyclohexanone; drywall finishers--total and respirable dust, hexane, acetone; painters--ethylene glycol, VOCs; masons--dust (during the preparation of mortar); floor preparation technicians--total and respirable dust; and ceramic tile installers--toluene, naphtha, silica (from grout powder).

Domestic exposure to endotoxin and respiratory morbidity in former smokers with COPD.

PubMed

Bose, S; Rivera-Mariani, F; Chen, R; Williams, D; Belli, A; Aloe, C; McCormack, M C; Breysse, P N; Hansel, N N

2016-10-01

Indoor air pollution has been linked to adverse chronic obstructive pulmonary disease (COPD) health, but specific causative agents have not yet been identified. We evaluated the role of indoor endotoxin exposure upon respiratory health in former smokers with COPD. Eighty-four adults with moderate to severe COPD were followed longitudinally and indoor air and dust samples collected at baseline, 3 and 6 months. Respiratory outcomes were repeatedly assessed at each time point. The associations between endotoxin exposure in air and settled dust and health outcomes were explored using generalizing estimating equations in multivariate models accounting for confounders. Dust endotoxin concentrations in the main living area were highest in spring and lowest in fall, while airborne endotoxins remained steady across seasons. Airborne and dust endotoxin concentrations were weakly correlated with one another (rs  = +0.24, P = 0.005). Endotoxin concentrations were not significantly associated with respiratory symptoms, rescue medication use, quality of life, or severe exacerbations. In vitro whole-blood assays of the pro-inflammatory capacity of PM10 filters with and without endotoxin depletion demonstrated that the endotoxin component of indoor air pollution was not the primary trigger for interleukin-1β release. Our findings support that endotoxin is not the major driver in the adverse effects of indoor PM upon COPD morbidity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Re-analysis of occupational hazards in foundry].

PubMed

Zhang, Min; Qi, Cheng; Chen, Wei-Hong; Lu, Yang; Du, Xie-Yi; Li, Wen-Jie; Meng, Chuan-San

2010-04-01

To analyze systematically the characteristics of occupational hazards in the foundry, and provide precise data for epidemiology studies and control of occupational hazards in the foundry. Data of airborne dust, chemical occupational hazards and physical occupational agents in environment in the foundry from 1978 to 2008 were dynamically collected. Mean concentration and intensity (geometric mean) of occupational hazards were calculated by job in different years. Main occupational hazards in the foundry were silica, metal fume, noise and heat stress. Silica existed in all of main jobs. The mean concentration of silica before 1986 was an extremely high level of 8.6 mg/m(3), and then remarkably dropped after 1986, with the level of 2.4 mg/m(3) from 1986 to 1989, 2.7 mg/m(3) from 1990 to 2002 and 2.7 mg/m(3) from 2003 to 2008. The trend of silica concentrations by job was consistent with that in general. Silica concentrations among jobs were significantly different, with highest level in melting (4.4 mg/m(3)), followed by cast shakeout and finishing (3.4 mg/m(3)), pouring (3.4 mg/m(3)), sand preparation (2.4 mg/m(3)), moulding (2.1 mg/m(3)) and core-making (1.7 mg/m(3)). Concentration of respirable dust in pouring was highest (2.76 mg/m(3)), followed by cast shakeout and finishing (1.14 mg/m(3)). Mean concentration of asbestos dust in melting was a relative high level of 2.0 mg/m(3). In core-making and sand preparation, there existed emission production of adhesive, with mean concentrations as followed, ammonia (5.84 mg/m(3)), formaldehyde (0.60 mg/m(3)), phenol (1.73 mg/m(3)) and phenol formaldehyde resin (1.3 mg/m(3)) also existed. Benzene and its homologues existed in cast shakeout and finishing, and the level of benzene, toluene, xylene was 0.2 mg/m(3), 0.1 mg/m(3) and 1.3 mg/m(3), respectively. In pouring and melting, there existed chemical occupational hazards, including benzo(a) pyrene, metal fume (lead, cadmium, manganese, nickel, chromium) and gas(hydrogen sulfide, phosphine, sulfur dioxide, carbon monoxide). Mean concentration of benzo(a) pyrene was a low level of 1.80 x 10(-4) microg/m(3). Physical occupational agents in the foundry were noise, heat stress and vibration. Intensity of heat stress was high in melting, pouring and cast shakeout and finishing, with the level of 30 degrees C, 29 degrees C and 26 degrees C, respectively. Noise was high in cast shakeout and finishing and core-making, with the level of 93.1 dB(A) and 89.5 dB(A), respectively. Vibration existed in core-making and cast shakeout and finishing. Compulsory postures included long standing, seating and bowing. Occupational hazards in environment of the foundry are diversified and their concentrations exceed permissible exposure limits stipulated by the national occupational hygienic standards. High-concentrations of dust, metal fume, low-concentrations of variety of chemicals, high-intensity of noise and vibration, heat stress, and harmful compulsory posture, and so on all co-exist in the foundry. Control and protective measures should be strengthened.

Tracing geogenic and anthropogenic sources in urban dusts: Insights from lead isotopes

NASA Astrophysics Data System (ADS)

Del Rio-Salas, R.; Ruiz, J.; De la O-Villanueva, M.; Valencia-Moreno, M.; Moreno-Rodríguez, V.; Gómez-Alvarez, A.; Grijalva, T.; Mendivil, H.; Paz-Moreno, F.; Meza-Figueroa, D.

2012-12-01

Tracing the source of metals in the environment is critical to understanding their pollution level and fate. Geologic materials are an important source of airborne particulate matter, but the contribution of contaminated soil to concentrations of Pb in airborne dust is not yet widely documented. To examine the potential significance of this mechanism, surface soil samples were collected, as well as wind-transported dust trapped at 1 and 2 m height at seven different locations including residential, industrial, high-traffic and rural sites. Samples of dust deposited on roofs from 24 schools were also obtained and analyzed for Pb isotope ratios. Spatial distribution of Pb of airborne and sedimented dust suggests a process dominated by re-suspension/sedimentation, which was controlled by erosion, traffic and topography of the urban area. Anthropogenic lead input in the city grades outward the urban zone toward geogenic values. Our results shows that Pb-isotopic signatures of leaded gasoline are imprinted in dust sedimented on roofs. Considering that leaded-gasoline has not been in use in Mexico since two decades ago, this signature shows not only a Pb-legacy in soil, but also a re-suspension process affecting air column below 3 m in height. The combination of the 207Pb/206Pb data of the surrounding rocks and urban dust, reveal three well-defined zones with remarkable anthropogenic influence, which correspond to the oldest urban sectors. This work highlights the importance of spatial characterization of metals in particles suspended below a height of 3 m of the airborne column, a fact that should be considered to identify exposure paths to humans and the potential risks. Lead isotope signatures allowed the identification of geogenic and anthropogenic emission sources for dust, a matter that deserves consideration in the efforts to control airborne metal emissions.

Surfactant-aided coal dust suppression: A review of evaluation methods and influencing factors.

PubMed

Xu, Guang; Chen, Yinping; Eksteen, Jacques; Xu, Jialin

2018-10-15

There is an increasing trend in the occurrence of coal worker's pneumoconiosis even in developed countries such as the US and Australia who have believed such an issue have been well controlled in the past. Water spray is one of the most commonly applied methods for underground coal mines dust control, and research have shown the dust suppression efficiency can be greatly improved by adding surfactants. However, the literature appears to show inconsistent results that do not provide the coal mining industry with a clearly effective solution. The breakthrough in this field relies on the achievements in prior work, but an up-to-date critical review was not found. By critically reviewing prior studies, this paper highlights the advances in the surfactant-aided coal dust suppression technology. Firstly, the surfactant chemical structure, surfactant type and mechanism of surfactant adsorption were explained. Secondly, the commonly used surfactant efficiency evaluation methods were described. This is important for producing comparable and reproducible results. After that, key aspects of the influencing factors were discussed, which are essential for developing effective and robust dust suppression products. In the discussion on the challenges and further research directions, we suggest more focus should be on the dynamic interaction between the coal particle and water droplet in wind tunnels or well controlled onsite conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

[The characteristics of type I, III collagen and LN in pulmonary fibrosis induced by uranium ore dust in rats].

PubMed

Hu, Ying-chun; Luo, Zhen-hua; Yuan, Xing-jiang; Yang, Li-ping; Wang, Shou-feng; Li, Guang-yue; He, Xing-peng

2011-02-01

To explore the characteristics of LN and type I, III collagen in pulmonary fibrosis induced by uranium ore dust in rats. 60 adult Wistar rats were divided randomly into two groups, control group (30 rats) and uranium ore dust group (30 rats). Non-exposed intratracheal instillation method was used. Uranium ore dust group was exposed 20 mg/ml uranium ore dust suspension 1ml per rat, meanwhile control group was exposed normal saline 1ml per rat. Post-exposed the 7, 14, 21, 30 and 60 d, 6 rats in each group were killed randomly, lung tissue were collected. The pathological changes in lung tissue were observed by microscope using HE staining, the collagen I and III in lungs were observed by polarizing microscope using Biebrich scarlet staining. The expression of LN protein in lung tissue was observed by immunohistochemistry-SP. During lung fibrosis, a large amount of the proliferated I and III collagen in lungs were observed. Post-exposure to uranium ore dust, the characteristics in proliferated collagen in lungs were type I collagen deposited in lung interstitium mainly in the early stage. The area percentage of collagen I and III was increased significantly at 7, 14, 21, 30 and 60d in the experimental group as compared with that in the control group (P < 0.05 or P < 0.01). The over expression of LN in the lung tissue were observed. The expression of LN was distributed in the lung tissue as thickening of the linear or cluster. The integral optical density of LN was increased significantly at 21, 30 and 60 d in the experimental group as compared with that in the control group (P < 0.05 or P < 0.01). After exposure to uranium ore dust, the characteristics in proliferated collagen in lungs are the type of I collagen deposited in lung interstitium mainly in the early stage, while the type of III collagen increase significantly at the later period. The overexpression of LN exists in the process of pulmonary fibrosis. It suggests that LN has a role effect in the process of pulmonary fibrosis.

Waste streams in a typical crewed space habitat: An update

NASA Technical Reports Server (NTRS)

Golub, M. A.; Wydeven, T.

1992-01-01

A compilation of generation rates and chemical compositions of potential waste streams in a typical crewed space habitat, reported in a prior NASA Technical Memorandum and a related journal article, was updated. This report augments that compilation by the inclusion of the following new data: those data uncovered since completion of the prior report; those obtained from Soviet literature relevant to life support issues; and those for various minor human body wastes not presented previously (saliva, flatus, hair, finger- and toenails, dried skin and skin secretions, tears, and semen), but included here for purposes of completeness. These waste streams complement those discussed previously: toilet waste (urine, feces, etc.), hygiene water (laundry, shower/handwash, dishwasher water and cleansing agents), trash, humidity condensate, perspiration and respiration water, trace contaminants, and dust generation. This report also reproduces the latest information on the environmental control and life support system design parameters for Space Station Freedom.

PRN 2001-X Draft: Spray and Dust Drift Label Statements for Pesticide Products

EPA Pesticide Factsheets

This Notice sets forth the U.S. Environmental Protection Agency's (EPA or Agency) draft guidance for labeling statements for controlling spray drift and dust drift from application sites and for implementing these statements for risk mitigation.

Hypersensitivity pneumonitis: a complex lung disease.

PubMed

Riario Sforza, Gian Galeazzo; Marinou, Androula

2017-01-01

Hypersensitivity pneumonitis (HP), also called extrinsic allergic alveolitis, is a respiratory syndrome involving the lung parenchyma and specifically the alveoli, terminal bronchioli, and alveolar interstitium, due to a delayed allergic reaction. Such reaction is secondary to a repeated and prolonged inhalation of different types of organic dusts or other substances to which the patient is sensitized and hyper responsive, primarily consisting of organic dusts of animal or vegetable origin, more rarely from chemicals. The prevalence of HP is difficult to evaluate because of uncertainties in detection and misdiagnosis and lacking of widely accepted diagnostic criteria, and varies considerably depending on disease definition, diagnostic methods, exposure modalities, geographical conditions, agricultural and industrial practices, and host risk factors. HP can be caused by multiple agents that are present in work places and in the home, such as microbes, animal and plant proteins, organic and inorganic chemicals. The number of environment, settings and causative agents is increasing over time. From the clinical point of view HP can be divided in acute/subacute and chronic, depending on the intensity and frequency of exposure to causative antigens. The mainstay in managing HP is the avoidance of the causative antigen, though the complete removal is not always possible due to the difficulties to identify the agent or because its avoidance may lead to major changes in life style or occupational settings. HP is a complex syndrome that needs urgently for more stringent and selective diagnostic criteria and validation, including wider panels of IgG, and a closer collaboration with occupational physicians, as part of a multidisciplinary expertise.

Meteorological aspects associated with dust storms in the Sistan region, southeastern Iran

NASA Astrophysics Data System (ADS)

Kaskaoutis, D. G.; Rashki, A.; Houssos, E. E.; Mofidi, A.; Goto, D.; Bartzokas, A.; Francois, P.; Legrand, M.

2015-07-01

Dust storms are considered natural hazards that seriously affect atmospheric conditions, ecosystems and human health. A key requirement for investigating the dust life cycle is the analysis of the meteorological (synoptic and dynamic) processes that control dust emission, uplift and transport. The present work focuses on examining the synoptic and dynamic meteorological conditions associated with dust-storms in the Sistan region, southeastern Iran during the summer season (June-September) of the years 2001-2012. The dust-storm days (total number of 356) are related to visibility records below 1 km at Zabol meteorological station, located near to the dust source. RegCM4 model simulations indicate that the intense northern Levar wind, the high surface heating and the valley-like characteristics of the region strongly affect the meteorological dynamics and the formation of a low-level jet that are strongly linked with dust exposures. The intra-annual evolution of the dust storms does not seem to be significantly associated with El-Nino Southern Oscillation, despite the fact that most of the dust-storms are related to positive values of Oceanic Nino Index. National Center for Environmental Prediction/National Center for Atmospheric Research reanalysis suggests that the dust storms are associated with low sea-level pressure conditions over the whole south Asia, while at 700 hPa level a trough of low geopotential heights over India along with a ridge over Arabia and central Iran is the common scenario. A significant finding is that the dust storms over Sistan are found to be associated with a pronounced increase of the anticyclone over the Caspian Sea, enhancing the west-to-east pressure gradient and, therefore, the blowing of Levar. Infrared Difference Dust Index values highlight the intensity of the Sistan dust storms, while the SPRINTARS model simulates the dust loading and concentration reasonably well, since the dust storms are usually associated with peaks in model simulations.

Air cleaning performance of a new environmentally controlled primary crusher operator booth

PubMed Central

Organiscak, J.A.; Cecala, A.B.; Zimmer, J.A.; Holen, B.; Baregi, J.R.

2016-01-01

The National Institute for Occupational Safety and Health (NIOSH) cooperated with 3M Company in the design and testing of a new environmentally controlled primary crusher operator booth at the company’s Wausau granite quarry near Wausau, WI. This quarry had an older crusher booth without a central heating, ventilation and air conditioning (HVAC) system, and without an air filtration and pressurization system. A new replacement operator booth was designed and installed by 3M based on design considerations from past NIOSH research on enclosed cab filtration systems. NIOSH conducted pre-testing of the old booth and post-testing of the new booth to assess the new filtration and pressurization system’s effectiveness in controlling airborne dusts and particulates. The booth’s dust and particulate control effectiveness is described by its protection factor, expressed as a ratio of the outside to inside concentrations measured during testing. Results indicate that the old booth provided negligible airborne respirable dust protection and low particulate protection from the outside environment. The newly installed booth provided average respirable dust protection factors from 2 to 25 over five shifts of dust sampling with occasional worker ingress and egress from the booth, allowing some unfiltered contaminants to enter the enclosure. Shorter-term particle count testing outside and inside the booth under near-steady-state conditions, with no workers entering or exiting the booth, resulted in protection factors from 35 to 127 on 0.3- to 1.0-μm respirable size particulates under various HVAC airflow operating conditions. PMID:26937052

Induction of chromosome aberrations in cultured human lymphocytes treated with sand dust storm fine particles (PM2.5).

PubMed

Wei, Aili; Meng, Ziqiang

2006-09-30

The clastogenic activity of airborne air fine particulate matter (PM2.5, particulates with an aerodynamic diameter < or =2.5 microm) has already been demonstrated. However little is known about the health risks associated with sand dust storm PM2.5 and its extract. In order to investigate the clastogenic activity of sand dust storm PM2.5 (include its organic and inorganic extract) on human lymphocytes, the normal PM2.5 and sand dust storm PM2.5 samples were collected in Wuwei city (Gansu Province) and Baotou city (Inner Mongolia), China. The chromosomal aberration (CA) test was employed and the cells were treated with 0, 33, 100, 300 microg ml(-1) sand dust storm or normal ambient air PM2.5 suspension (physiological saline as solvent control), or inorganic extract (0, 75, 150, 300 microg ml(-1), physiological saline as solvent control) or organic extract (0, 20, 40, 80 microg ml(-1), DMSO as solvent control) at the beginning of the cell culture. The results indicated that sand dust storm PM2.5 and its extract as well as normal samples can induce increase in CA frequency. With the increase of treatment concentrations the CA frequency increased and the mitotic index (MI) values declined in a dose-response manner. In the same concentrates, the CA frequency of normal ambient air PM2.5 and its extract were significant higher than those of sand dust storm PM2.5 (P<0.05 or 0.01) except the treatment of Wuwei sample at higher doses (100, 300 microg ml(-1)), the treatment of inorganic extract of PM2.5 at the highest dose (300 microg ml(-1)) and the treatment of organic extract of PM2.5 at the higher dose (40 and 80 microg ml(-1)) either in Baotou or in Wuwei (P>0.05). The toxicity of sand dust storm PM2.5 and its extract at high dose is very potent. CA frequency of normal PM2.5 (include its organic extract) from Baotou were higher than those of Wuwei especially in low and middle dose (P<0.05), but the treatment results of sand dust storm PM2.5 (include its all extract) was not significant different between the cities (P>0.05).

Sensitization of children in the Stockholm area to house dust mites.

PubMed

Nordvall, S L; Eriksson, M; Rylander, E; Schwartz, B

1988-09-01

Atopic sensitization of children in the Stockholm area to house dust mites (HDM) was investigated in a case-control study. Sixty children with and 60 without positive skin prick tests for HDM were matched for age and sex. HDM-sensitized children had previously more often lived in other areas known to be mite infested than the control children. Sensitization to mites was related to dampness in the homes, but no significant relationship was found to the type of residence, frequent visits to a summer house in the archipelago or parental smoking. Dust samples from mattresses of the children with the strongest positive reactions to mites in skin prick tests and the respective controls were subjected to an enzyme immunoassay, to measure the content of the major allergens of the Dermatophagoides (D.) species D. pterinyssinus, D. farinae and D. microceras. Mattress dust samples from the beds of HDM-sensitized children contained significantly higher HDM antigen concentrations than those from the beds of controls. Private houses contained significantly more HDM antigens than flats and 10 of 11 homes in which a dampness problem was recognized contained mite antigens. It is postulated that mite infestation is increasing in the area, energy-saving measures creating improved conditions for HDM survival.

Occupational exposure to wood dust and health effects on the respiratory system in a minor industrial estate in Bursa, Turkey.

PubMed

Osman, Erdinç; Pala, Kayihan

2009-01-01

The aim of this study was to estimate occupational exposure to wood dust in the furniture industry in a minor industrial estate in Bursa, Turkey. The study was conducted between October 2006 and May 2007. In this study, a total of 656 persons, 328 woodworkers and 328 controls were included. A questionnaire was used in the study. Physical examination and the pulmonary function tests (MIR-Spirobank G) of the workers were performed. A portable Aircheck 2000 pump was used to collect the specimens of wood dust from the workplaces. NIOSH Method 0500 was employed for the gravimetric measurements of dust. The average dust concentration at the workplace was 2.04+/-1.53 mg/m3. It was reported that 176 of workers (53.7%) had blocked nose while working, 141 (43.0%) had redness of the eyes, 135 (41.2%) had itching eyes and 78 (23.8%) had runny nose. No symptoms were observed in the control group while they were working at the workplace. The mean FEV1 and FVC values of woodworkers, among both smokers and non smokers, were significantly low, although the FEV1/FVC value was high (p < 0.05). An increase both in FEV1 and FVC values was detected among the woodworkers who had a working period less than 10 years and were exposed to wood dust at concentrations over 4 mg/m3 compared to the woodworkers who were exposed to wood dust at less than 4 mg/m3 (p < 0.05). As a result, in this study it was pointed out that the exposure to wood dust adversely influenced the workers respiratory functions. Besides, in this study a question associated with the healthy worker effect that can adversely influence health of workers exposed to wood dust at less than (4 mg/m3) is revealed.

Signaling Pathways Involved in Lunar Dust Induced Cytotoxicity

NASA Technical Reports Server (NTRS)

Zhang, Ye; Lam, Chiu-Wing; Scully, Robert R.; Williams, Kyle; Zalesak, Selina; Wu, Honglu; James, John T.

2014-01-01

The Moon's surface is covered by a layer of fine, reactive dust. Lunar dust contain about 1-2% of very fine dust (< 3 micron), that is respirable. The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to evaluate the toxicity of Apollo moon dust in rodents to assess the health risk of dust exposures to humans. One of the particular interests in the study is to evaluate dust-induced changes of the expression of fibrosis-related genes, and to identify specific signaling pathways involved in lunar dust-induced toxicity. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose-only inhalation chambers to concentrations of 0 (control air), 2.1, 6.1, 21, and 61 mg/m(exp 3) of lunar dust. Five rats per group were euthanized 1 day, 1 week, 1 month, and 3 months after the last inhalation exposure. The total RNAs were isolated from the blood or lung tissue after being lavaged, using the Qigen RNeasy kit. The Rat Fibrosis RT2 Profile PCR Array was used to profile the expression of 84 genes relevant to fibrosis. The genes with significant expression changes are identified and the gene expression data were further analyzed using IPA pathway analysis tool to determine the signaling pathways with significant changes.

Climate change and climate systems influence and control the atmospheric dispersion of desert dust: implications for human health

USGS Publications Warehouse

Griffin, Dale W.; Ragaini, Richard C.

2010-01-01

The global dispersion of desert dust through Earth’s atmosphere is greatly influenced by temperature. Temporal analyses of ice core data have demonstrated that enhanced dust dispersion occurs during glacial events. This is due to an increase in ice cover, which results in an increase in drier terrestrial cover. A shorter temporal analysis of dust dispersion data over the last 40 years has demonstrated an increase in dust transport. Climate systems or events such as the North Atlantic Oscillation, the Indian Ocean subtropical High, Pacific Decadal Oscillation, and El Nino-Sothern Oscillation are known to influence global short-term dust dispersion occurrence and transport routes. Anthropogenic influences on dust transport include deforestation, harmful use of topsoil for agriculture as observed during the American Dust Bowl period, and the creation of dry seas (Aral Sea) and lakes (Lake Owens in California and Lake Chad in North Africa) through the diversion of source waters (for irrigation and drinking water supplies). Constituents of desert dust both from source regions (pathogenic microorganisms, organic and inorganic toxins) and those scavenged through atmospheric transport (i.e., industrial and agricultural emissions) are known to directly impact human and ecosystem health. This presentation will present a review of global scale dust storms and how these events can be both a detriment and benefit to various organisms in downwind environments.

[SUVA (Swiss Accident Insurance Fund) and silicosis. Silicosis in Switzerland. Development of technological dust control].

PubMed

Bachofen, G

1983-01-01

In Switzerland the technical measures against quartz dust started in 1948 when wet drilling was compulsoryly introduced, initially in underground mining. The miners using the first wet drilling machines had serious problems with water, and only with the introduction of carriage drilling machines in 1963 did the method fully break through. Dust caused by blasting operations and by loading of the resultant material was limited by ventilation and sprinkling of water. In 1966 the first full-face cutting machines were used, and it was necessary to install a dust chamber behind the drill from which dust could be taken to a dust arrester. The problem of dust limitation when using boom cutters at sectional areas of more than 20 sq. meters without a pilot tunnel has not been resolved. Since 1970, dust in quarries and stone-cutter workshops has been successfully combated by the use of exhaust pumps in combination with filters. The use of quartz sand to clean metal pieces (sandblast) was forbidden in 1960. Today, materials of the same value, but quartz-free, are available. In foundries, dust production can be limited by continuous automation and installation of exhaust pumps in moulding units. For more than 30 years now the technical equipment has been available for successful prevention of quartz dust emissions. However, at some plants it is still difficult to persuade the personnel to use the protective equipment.

Long-Term Simulation of Dust Distribution with the GOCART Model: Correlation with the North Atlantic Oscillation

NASA Technical Reports Server (NTRS)

Ginoux, P.; Prospero, J.; Torres, O.; Chin, M.

2002-01-01

Global distribution of aeolian dust is simulated from 1981 to 1996 with the Goddard Ozone Chemistry Aerosol Radiation and Transport (GOCART) model. The results are assessed with in-situ measurements and the Total Ozone Mapping Spectrometer (TOMS) aerosol products. The annual budget over the different continents and oceans are analyzed. It is found that there is a maximum of 25% difference of global annual emission from the minimum in 1996 to the maximum in 1988. There is a downward trend of dust emission over Africa and East Asia, of 6 and 2 Tg/yr, respectively. The inter-annual variability of dust distribution is analyzed over the North Atlantic and Africa. It is found that in winter most of the North Atlantic and Africa dust loading is correlated with the North Atlantic Oscillation. The GOCART model indicates that a controlling factor of such correlation can be attributed to dust emission from the Sahel. The Bodele depression is the major dust source in winter and its inter-annual variability is highly correlated with the NAO. However, it is not possible to conclude without further analysis that the North Atlantic Oscillation is forcing the inter-annual variability of dust emission and in-turn dust concentration over the North Atlantic.

Dust exposure and pneumoconiosis in a South African pottery. 1. Study objectives and dust exposure.

PubMed Central

Rees, D; Cronje, R; du Toit, R S

1992-01-01

Dust exposure and pneumoconiosis were investigated in a South African pottery that manufactured wall tiles and bathroom fittings. This paper describes the objectives of the investigation and presents dust measurement data. x Ray diffraction showed that the clays used by the pottery had a high quartz content (range 58%-23%, mean 38%). Exposure to respirable dust was measured for 43 workers and was highest (6.6 mg/m3) in a bathroom fitting fettler. Quartz concentrations in excess of 0.1 mg/m3 were found in all sections of the manufacturing process from slip production to biscuit firing and sorting. The proportion of quartz in the respirable dust of these sections was 24% to 33%. This is higher than is usually reported in English potteries. Four hundred and six (80%) of the 509 workers employed at the pottery were potentially at risk of occupational lung disease. The finding of large numbers of pottery workers exposed to unacceptable dust concentrations is not surprising as poor dust control was found in all six wall tile and sanitary ware factories surveyed by the National Centre for Occupational Health between 1973 and 1989. Dust related occupational disease can be expected in potters for many years to come. PMID:1637705

Dust exposure and pneumoconiosis in a South African pottery. 1. Study objectives and dust exposure.

PubMed

Rees, D; Cronje, R; du Toit, R S

1992-07-01

Dust exposure and pneumoconiosis were investigated in a South African pottery that manufactured wall tiles and bathroom fittings. This paper describes the objectives of the investigation and presents dust measurement data. x Ray diffraction showed that the clays used by the pottery had a high quartz content (range 58%-23%, mean 38%). Exposure to respirable dust was measured for 43 workers and was highest (6.6 mg/m3) in a bathroom fitting fettler. Quartz concentrations in excess of 0.1 mg/m3 were found in all sections of the manufacturing process from slip production to biscuit firing and sorting. The proportion of quartz in the respirable dust of these sections was 24% to 33%. This is higher than is usually reported in English potteries. Four hundred and six (80%) of the 509 workers employed at the pottery were potentially at risk of occupational lung disease. The finding of large numbers of pottery workers exposed to unacceptable dust concentrations is not surprising as poor dust control was found in all six wall tile and sanitary ware factories surveyed by the National Centre for Occupational Health between 1973 and 1989. Dust related occupational disease can be expected in potters for many years to come.

Level and distribution of employee exposures to total and respirable wood dust in two Canadian sawmills.

PubMed

Teschke, K; Hertzman, C; Morrison, B

1994-03-01

Personal respirable (N = 230) and total (N = 237) dust measurements were made in two coastal British Columbia sawmills using a sampling strategy that randomly selected workers from all jobs in the mills over two seasons. Information about job title, department, season, weather conditions, location of the job relative to wood-cutting machines, and control measures also was collected at the time of sampling. Only 16 respirable wood dust samples were above the detection limit of 0.08 mg/m3; all 16 had levels < or = 0.20 mg/m3. Total wood dust concentrations were also low (36% less than the detection limit), with a mean of 0.51 mg/m3, and ranging from < 0.08 to 52 mg/m3. Measurements of exposure taken close to chippers, planers, and multiple saws had the highest total wood dust levels. Sawmill department and booth enclosures also were associated with wood dust concentrations, while local exhaust ventilation and weather conditions were not. Wood dust levels in this study were generally lower than in other studies of this industry, but most sawmill investigations report mean wood dust concentrations lower than those measured in the furniture and cabinetmaking industries, where concerns about wood dust exposures initially were raised.

A new dust source map of Central Asia derived from MODIS Terra/Aqua data using dust enhancement techniques

NASA Astrophysics Data System (ADS)

Nobakht, Mohamad; Shahgedanova, Maria; White, Kevin

2017-04-01

Central Asian deserts are a significant source of dust in the middle latitudes, where economic activity and health of millions of people are affected by dust storms. Detailed knowledge of sources of dust, controls over their activity, seasonality and atmospheric pathways are of crucial importance but to date, these data are limited. This paper presents a detailed database of sources of dust emissions in Central Asia, from western China to the Caspian Sea, obtained from the analysis of the Moderate Resolution Imaging Spectroradiometer (MODIS) data between 2003 and 2012. A dust enhancement algorithm was employed to obtain two composite images per day at 1 km resolution from MODIS Terra/Aqua acquisitions, from which dust point sources (DPS) were detected by visual analysis and recorded in a database together with meteorological variables at each DPS location. Spatial analysis of DPS has revealed several active source regions, including some which were not widely discussed in literature before (e.g. Northern Afghanistan sources, Betpak-Dala region in western Kazakhstan). Investigation of land surface characteristics and meteorological conditions at each source region revealed mechanisms for the formation of dust sources, including post-fire wind erosion (e.g. Lake Balkhash basin) and rapid desertification (e.g. the Aral Sea). Different seasonal patterns of dust emissions were observed as well as inter-annual trends. The most notable feature was an increase in dust activity in the Aral Kum.

High-latitude dust in the Earth system

USGS Publications Warehouse

Bullard, Joanna E; Baddock, Matthew; Bradwell, Tom; Crusius, John; Darlington, Eleanor; Gaiero, Diego; Gasso, Santiago; Gisladottir, Gudrun; Hodgkins, Richard; McCulloch, Robert; NcKenna Neuman, Cheryl; Mockford, Tom; Stewart, Helena; Thorsteinsson, Throstur

2016-01-01

Natural dust is often associated with hot, subtropical deserts, but significant dust events have been reported from cold, high latitudes. This review synthesizes current understanding of high-latitude (≥50°N and ≥40°S) dust source geography and dynamics and provides a prospectus for future research on the topic. Although the fundamental processes controlling aeolian dust emissions in high latitudes are essentially the same as in temperate regions, there are additional processes specific to or enhanced in cold regions. These include low temperatures, humidity, strong winds, permafrost and niveo-aeolian processes all of which can affect the efficiency of dust emission and distribution of sediments. Dust deposition at high latitudes can provide nutrients to the marine system, specifically by contributing iron to high-nutrient, low-chlorophyll oceans; it also affects ice albedo and melt rates. There have been no attempts to quantify systematically the expanse, characteristics, or dynamics of high-latitude dust sources. To address this, we identify and compare the main sources and drivers of dust emissions in the Northern (Alaska, Canada, Greenland, and Iceland) and Southern (Antarctica, New Zealand, and Patagonia) Hemispheres. The scarcity of year-round observations and limitations of satellite remote sensing data at high latitudes are discussed. It is estimated that under contemporary conditions high-latitude sources cover >500,000 km2 and contribute at least 80–100 Tg yr−1 of dust to the Earth system (~5% of the global dust budget); both are projected to increase under future climate change scenarios.

High Latitude Dust in the Earth System

NASA Technical Reports Server (NTRS)

Bullard, Joanna E.; Baddock, Matthew; Bradwell, Tom; Crusius, John; Darlington, Eleanor; Gaiero, Diego; Gasso, Santiago; Gisladottir, Gudrun; Hodgkins, Richard; McCulloch, Robert;

Khuzestan dust phenomenon: a content analysis of most widely circulated newspapers.

PubMed

Mojadam, Mehdi; Matlabi, Mohammad; Haji, Alireza; Cheraghi, Maria; Bitaraf, Saeid; Khafaie, Morteza Abdullatif

2018-06-01

Dust is an atmospheric phenomenon that causes adverse environmental effects. It is deemed to have harmful effects on health, economics, and climate. This study aimed to analyze the content published on the phenomenon of dust in the widely circulated newspapers in Iran. We investigated the content of all national and provincial newspapers that were published between July and August 2014. Data on the materials related to the dust phenomenon in the newspapers were categorized and coded. From a total of 510 newspaper issues, 143 articles were devoted to the dust phenomenon which 74.1% of them were published in provincial newspapers. Among the national newspapers, Hamshahri newspaper with 16 headlines and from the provincial newspapers; Karoon with 23 headlines published the highest number of articles on dust phenomenon. 45.5% of content on dust were printed on the first page of the newspapers. The most common approach to the type of content published in these newspapers was an interview. Moreover, we noticed that 28.7% of the content published in the newspapers was related to the health issue. The media plays an important role in the transmission of health information. Weaknesses in addressing the causes of dust occurrence and also in providing solutions for the dust control and prevention were noticeable in the content published in the newspaper. It seems necessary to take practical measures to disseminate relevant information to dust and also address the needs of the target audience community influenced by the dust phenomenon properly.

Interannual Variability of Dust and Ice in the Mars Atmosphere: Comparison of MRO Mars Climate Sounder Retrievals with MGS-TES Limb Sounding Retrievals

NASA Technical Reports Server (NTRS)

Shirley, J. H.; McConnochie, T. H.; Kleinbohl, A.; Schofield, J. T.; Kass, D.; Heavens, N. G.; Benson, J.; McCleese, D. J.

2011-01-01

Dust and ice play important roles in Martian atmospheric dynamics on all time scales. Dust loading in particular exerts an important control on atmospheric temperatures and thereby on the strength of the atmospheric circulation in any given year. We present the first comparisons of MGS-TES aerosol opacity profiles with MRO-MCS aerosol opacity profiles. While the differences in vertical resolution are significant (a factor of 2), we find good agreement at particular seasons between nightside zonal average dust opacity profiles from the two instruments. Derived water ice opacities are likewise similar but show greater variability.

An Electrostatic Precipitator System for the Martian Environment

NASA Technical Reports Server (NTRS)

Calle, C. I.; Mackey, P. J.; Hogue, M. D.; Johansen, M. R.; Phillips, J. R., III; Clements, J. S.

2012-01-01

Human exploration missions to Mars will require the development of technologies for the utilization of the planet's own resources for the production of commodities. However, the Martian atmosphere contains large amounts of dust. The extraction of commodities from this atmosphere requires prior removal of this dust. We report on our development of an electrostatic precipitator able to collect Martian simulated dust particles in atmospheric conditions approaching those of Mars. Extensive experiments with an initial prototype in a simulated Martian atmosphere showed efficiencies of 99%. The design of a second prototype with aerosolized Martian simulated dust in a flow-through is described. Keywords: Space applications, electrostatic precipitator, particle control, particle charging

Biological effects of desert dust in respiratory epithelial cells and a murine model.

PubMed

Ghio, Andrew J; Kummarapurugu, Suryanaren T; Tong, Haiyan; Soukup, Joleen M; Dailey, Lisa A; Boykin, Elizabeth; Ian Gilmour, M; Ingram, Peter; Roggli, Victor L; Goldstein, Harland L; Reynolds, Richard L

2014-04-01

As a result of the challenge of recent dust storms to public health, we tested the postulate that desert dust collected in the southwestern United States imparts a biological effect in respiratory epithelial cells and an animal model. Two samples of surface sediment were collected from separate dust sources in northeastern Arizona. Analysis of the PM20 fraction demonstrated that the majority of both dust samples were quartz and clay minerals (total SiO₂ of 52 and 57%). Using respiratory epithelial and monocytic cell lines, the two desert dusts increased oxidant generation, measured by Amplex Red fluorescence, along with carbon black (a control particle), silica, and NIST 1649 (an ambient air pollution particle). Cell oxidant generation was greatest following exposures to silica and the desert dusts. Similarly, changes in RNA for superoxide dismutase-1, heme oxygenase-1, and cyclooxygenase-2 were also greatest after silica and the desert dusts supporting an oxidative stress after cell exposure. Silica, desert dusts, and the ambient air pollution particle NIST 1649 demonstrated a capacity to activate the p38 and ERK1/2 pathways and release pro-inflammatory mediators. Mice, instilled with the same particles, showed the greatest lavage concentrations of pro-inflammatory mediators, neutrophils, and lung injury following silica and desert dusts. We conclude that, comparable to other particles, desert dusts have a capacity to (1) influence oxidative stress and release of pro-inflammatory mediators in respiratory epithelial cells and (2) provoke an inflammatory injury in the lower respiratory tract of an animal model. The biological effects of desert dusts approximated those of silica.

Biological effects of desert dust in respiratory epithelial cells and a murine model

USGS Publications Warehouse

Ghio, Andrew J.; Kummarapurugu, Suryanaren T.; Tong, Haiyan; Soukup, Joleen M.; Dailey, Lisa A.; Boykin, Elizabeth; Gilmour, M. Ian; Ingram, Peter; Roggli, Victor L.; Goldstein, Harland L.; Reynolds, Richard L.

2014-01-01

As a result of the challenge of recent dust storms to public health, we tested the postulate that desert dust collected in the southwestern United States imparts a biological effect in respiratory epithelial cells and an animal model. Two samples of surface sediment were collected from separate dust sources in northeastern Arizona. Analysis of the PM20 fraction demonstrated that the majority of both dust samples were quartz and clay minerals (total SiO2 of 52 and 57%). Using respiratory epithelial and monocytic cell lines, the two desert dusts increased oxidant generation, measured by Amplex Red fluorescence, along with carbon black (a control particle), silica, and NIST 1649 (an ambient air pollution particle). Cell oxidant generation was greatest following exposures to silica and the desert dusts. Similarly, changes in RNA for superoxide dismutase-1, heme oxygenase-1, and cyclooxygenase-2 were also greatest after silica and the desert dusts supporting an oxidative stress after cell exposure. Silica, desert dusts, and the ambient air pollution particle NIST 1649 demonstrated a capacity to activate the p38 and ERK1/2 pathways and release pro-inflammatory mediators. Mice, instilled with the same particles, showed the greatest lavage concentrations of pro-inflammatory mediators, neutrophils, and lung injury following silica and desert dusts. We conclude that, comparable to other particles, desert dusts have a capacity to (1) influence oxidative stress and release of pro-inflammatory mediators in respiratory epithelial cells and (2) provoke an inflammatory injury in the lower respiratory tract of an animal model. The biological effects of desert dusts approximated those of silica.

Characterization of dustfall in rural and urban sites during three dust storms in northern China, 2010

NASA Astrophysics Data System (ADS)

Lyu, Yanli; Qu, Zhiqiang; Liu, Lianyou; Guo, Lanlan; Yang, Yanyan; Hu, Xia; Xiong, Yiying; Zhang, Guoming; Zhao, Mengdi; Liang, Bo; Dai, Jiadong; Zuo, Xiyang; Jia, Qingpan; Zheng, Hao; Han, Xujiao; Zhao, Shoudong; Liu, Qi

2017-10-01

Dust transport and deposition processes are important for understanding the environmental risk of dust storms. This study investigated characteristics of dustfall at two rural sites and four urban sites from dust sources to downwind regions during three dust storms (DS1: March 19-22, DS2: April 24-26, DS3: May 7-10, 2010). Analysis of near-surface instantaneous maximum wind speed and prevailing wind direction revealed the dust storms bursted out from northwestern arid and semiarid regions to eastern China. Microaggregates, angular, subangular, columnar, subrounded, and spherical particles were identified by scanning electron microscope. Dust deposition flux (DDF) during the dust storms was significantly high at sites near sand deserts and sandy land. During DS2, DDF was 25.1, 9.9, 2.3, and 1.5 g m-2 in Jingbian, Shapotou, Lanzhou, and Beijing, respectively. The three dust storms contributed 7.3% of Beijing's annual dustfall in 2010, which suggests anthropogenic dust might contribute the majority of annual dustfall in urban areas. The mass medium diameter of dustfall during DS2 in Shapotou, Jingbian, Lanzhou, and Beijing was 26.1, 9.0, 16.4, and 15.5 μm, respectively. Urban dustfall contained more heavy metals, sulfur and arsenic than rural dustfall. Cadmium contamination was identified in all urban dust particles. Anthropogenic pollutants in combination with mineral dust might lead to complex environmental risk on local, regional, and global scales. China's environmental pollution control should integrate reductions in land desertification and multisource anthropogenic emissions within the context of climate change mitigation.

Relationship of inflammatory cell cytokines to disease severity in individuals with occupational inorganic dust exposure.

PubMed

Rom, W N

1991-01-01

The pneumoconioses due to chronic occupational exposure to asbestos, coal, or silica are characterized by an alveolar macrophage-dominated alveolitis with exaggerated spontaneous release of mediators: oxidants, chemotaxins for neutrophils, and fibroblast growth factors. Bronchoalveolar lavage was performed on 66 non-smoking inorganic dust-exposed individuals with a chest x-ray greater than or equal to 1/0 stratified by presence or absence of restrictive respiratory impairment, and 28 unexposed non-smoking controls. Both dust-exposed groups stratified by presence or not of impairment had increased numbers of total cells recovered by lavage compared to normals, and those with respiratory impairment (n = 40) had a significant increase in percent and number of neutrophils recovered. Similarly, only those with respiratory impairment had macrophages that spontaneously released significant amounts of the oxidants superoxide anion and hydrogen peroxide. There was a significant trend for the release of fibronectin by macrophages from controls to dust-exposed without impairment to those with impairment. Both dust-exposed groups also had increased release of alveolar macrophage-derived progression growth factor, but this was significantly less than macrophages from patients with idiopathic pulmonary fibrosis. Since occupational exposure was virtually identical in inorganic dust-exposed individuals with versus without respiratory impairment, the quantitative differences in the release of macrophage mediators may be due to factors in host susceptibility.

SEASON OF DELTAMETHRIN APPLICATION AFFECTS FLEA AND PLAGUE CONTROL IN WHITE-TAILED PRAIRIE DOG (CYNOMYS LEUCURUS) COLONIES, COLORADO, USA.

PubMed

Tripp, Daniel W; Streich, Sean P; Sack, Danielle A; Martin, Daniel J; Griffin, Karen A; Miller, Michael W

2016-07-01

In 2008 and 2009, we evaluated the duration of prophylactic deltamethrin treatments in white-tailed prairie dog ( Cynomys leucurus ) colonies and compared effects of autumn or spring dust application in suppressing flea numbers and plague. Plague occurred before and during our experiment. Overall, flea abundance tended to increase from May or June to September, but it was affected by deltamethrin treatment and plague dynamics. Success in trapping prairie dogs (animals caught/trap days) declined between June and September at all study sites. However, by September trap success on dusted sites (19%; 95% confidence interval [CI] 16-22%) was about 15-fold greater than on undusted control sites (1%; CI 0.3-4%; P≤0.0001). Applying deltamethrin dust as early as 12 mo prior seemed to afford some protection to prairie dogs. Our data showed that dusting even a portion of a prairie dog colony can prolong its persistence despite epizootic plague. Autumn dusting may offer advantages over spring in suppressing overwinter or early-spring flea activity, but timing should be adjusted to precede the annual decline in aboveground activity for hibernating prairie dog species. Large colony complexes or collections of occupied but fragmented habitat may benefit from dusting some sites in spring and others in autumn to maximize flea suppression in a portion of the complex or habitat year-round.

Lead in Chinese villager house dust: Geographical variation and influencing factors.

PubMed

Bi, Xiangyang; Liu, Jinling; Han, Zhixuan; Yang, Wenlin

2015-12-01

House dust has been recognized as an important contributor to Pb exposure of children. Here we conducted a comprehensive study to investigate geographical variation of Pb in Chinese villager house dust. The influences of outdoor soil Pb concentrations, dates of construction, house decoration materials, heating types, and site specific pollution on Pb concentrations in house dust were evaluated. The concentrations of Pb in 477 house dust samples collected from twenty eight areas throughout China varied from 12 to 2510 mg/kg, with a median concentration of 42 mg/kg. The median Pb concentrations in different geographical areas ranged from 16 (Zhangjiakou, Hebei) to 195 mg/kg (Loudi, Hunan). No correlations were found between the house dust Pb concentrations and the age of houses, as well as house decoration materials. Whereas outdoor soil, coal combustion, and site specific pollution may be potential Pb sources. Principal component analysis (PCA) confirmed that elemental compositions of the house dust were controlled by both anthropogenic and geogenic sources. Using scanning electron microscopy (SEM), the Pb bearing particles in the house dust were also studied. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of the predictions of two road dust emission models with the measurements of a mobile van

NASA Astrophysics Data System (ADS)

Kauhaniemi, M.; Stojiljkovic, A.; Pirjola, L.; Karppinen, A.; Härkönen, J.; Kupiainen, K.; Kangas, L.; Aarnio, M. A.; Omstedt, G.; Denby, B. R.; Kukkonen, J.

2014-02-01

The predictions of two road dust suspension emission models were compared with the on-site mobile measurements of suspension emission factors. Such a quantitative comparison has not previously been reported in the reviewed literature. The models used were the Nordic collaboration model NORTRIP (NOn-exhaust Road TRaffic Induced Particle emissions) and the Swedish-Finnish FORE model (Forecasting Of Road dust Emissions). These models describe particulate matter generated by the wear of road surface due to traction control methods and processes that control the suspension of road dust particles into the air. An experimental measurement campaign was conducted using a mobile laboratory called SNIFFER, along two selected road segments in central Helsinki in 2007 and 2008. The suspended PM10 concentration was measured behind the left rear tyre and the street background PM10 concentration in front of the van. Both models reproduced the measured seasonal variation of suspension emission factors fairly well during both years at both measurement sites. However, both models substantially under-predicted the measured emission values. The results indicate that road dust emission models can be directly compared with mobile measurements; however, more extensive and versatile measurement campaigns will be needed in the future.

Meteorological Situations Favouring the Development of Dust Plumes over Iceland

NASA Astrophysics Data System (ADS)

Schepanski, K.; Szodry, K.

2017-12-01

The knowledge on mineral dust emitted at high latitudes is limited, but its impact on the polar environments is divers. Within a warming climate, dust emitted from regions in cold climates is expected to increase due to the retreat of the ice sheet and increasing melting rates. Therefore, and for its extensive impacts on different aspects of the climate system, a better understanding of the atmospheric dust life-cycle at high latitudes/cold climates in general, and the spatio-temporal distribution of dust sources in particular, are essential. At high-latitudes, glacio-fluvial sediments as found on river flood plains e.g. supplied by glaciers are prone to wind erosion when dry and bare. In case of the occurrence of strong winds, sediments are blown out and dust plumes develop. As dust uplift is controlled by soil surface characteristics, the availability of suitable sediments, and atmospheric conditions, an interannual variability in dust source activity is expected. We investigated atmospheric circulation patterns that favour the development of dust plumes over Iceland, which presents a well-known dust source at high latitudes. Using the atmosphere model COSMO (COnsortium for Small-scale MOdeling), we analysed the wind speed distribution over the Iceland region for identified and documented dust cases. As one outcome of the study, the position of the Icelandic low, the anticyclones located over Northern Europe, and the resulting pressure gradients are of particular relevance. The interaction of the synoptic-scale winds with the Icelandic orography may locally enhance the wind speeds and thus foster local dust emission. Results from this study suggest that the atmospheric circulation determined by the pressure pattern is of particular relevance for the formation of dust plumes entering the North Atlantic.

Exhaled breath malondialdehyde, spirometric results and dust exposure assessment in ceramics production workers.

PubMed

Sakhvidi, Mohammad Javad Zare; Biabani Ardekani, Javad; Firoozichahak, Ali; Zavarreza, Javad; Hajaghazade, Mohammad; Mostaghaci, Mehrdad; Mehrparvar, Amirhooshang; Barkhordari, Abolfazl

2015-01-01

The study aimed at measuring exhaled breath malondialdehyde (EBC-MDA) in workers exposed to dust containing silica and at its comparison with the non-exposed control group. The cross sectional, case-control study (N = 50) was performed in a tile and ceramics production factory in Yazd, Iran. EBC-MDA was quantified in exhaled breath of the participants by a lab made breath sampler. Exposure intensity was measured according to the NIOSH 0600 method in selected homogeneous exposure groups. Additionally, spirometry test was conducted to investigate a correlation between EBC-MDA and spirometric findings in the exposed workers. There was no difference in the observed exposure intensities of silica containing dust in different units. However, "coating preparation" was the unit with the highest concentration of dust. Although, the level of EBC-MDA in the cases was slightly higher than in the controls, the difference was not statistically significant (U = 252, p = 0.464). A significant and positive correlation was found between dust exposure intensity in working units and the measured EBC-MDA of workers (r = 0.467, N = 25, p = 0.027). There were also no statistically significant differences among job categories in the exposed group for the values of FEV1% (F(3, 44) = 0.656, p = 0.584), FVC% (F(3, 44) = 1.417, p = 0.172), and FEV1/FVC% (F(3, 44) = 1.929, p = 0.139). The results showed a significant correlation between respirable dust exposure intensity and the level of EBC-MDA of the exposed subjects. However, our results did not show a significant correlation between lung function decreases and EBC-MDA. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Effects of exposure to grain dust in Polish farmers: work-related symptoms and immunologic response to microbial antigens associated with dust.

PubMed

Skórska, C; Mackiewicz, B; Dutkiewicz, J; Krysińska-Traczyk, E; Milanowski, J; Feltovich, H; Lange, J; Thorne, P

1998-01-01

Medical examinations were performed in a group of 76 Polish farmers heavily exposed to grain dust during harvesting and threshing, and in a group of 63 healthy urban dwellers not exposed to organic dusts (controls). The examinations included: interview concerning the occurrence of respiratory disorders and work-related symptoms, physical examination, lung function tests, and allergological tests comprising skin prick test with 4 microbial antigens associated with grain dust and agar-gel precipitation test with 12 microbial antigens. As many as 34 farmers (44.7%) reported the occurrence of work-related symptoms during harvesting and threshing. The most common was dry cough reported by 20 individuals (26.3%). Dyspnoea was reported by 15 farmers (19.7%), tiredness by 12 (15.7%), chest tightness by 8 (10.5%), plugging of nose and hoarseness by 5 each (6. 5%). No control subjects reported these work-related symptoms. The mean spirometric values in the examined group of farmers were within the normal range, but a significant post-shift decrease of these values was observed after work with grain. The farmers showed a frequency of the positive early skin reactions to environmental allergens in the range of 10.8 - 45.5%, and a frequency of positive precipitin reactions in range of 3.9 - 40.8%. The control group responded to the majority of allergens with a significantly lower frequency of positive results compared to the farmers. The obtained results showed a high response of grain farmers to inhalant microbial allergens and indicate a potential risk of occupational respiratory diseases (such as allergic alveolitis, asthma, Organic Dust Toxic Syndrome) among this population

A Coupled Ice-Atmosphere-Dust Model for a Neoproterozoic "Mudball Earth"

NASA Astrophysics Data System (ADS)

Goodman, J. C.; Strom, D.

2010-12-01

The Neoproterozoic "Snowball Earth" glaciations remain a subject of intense debate. While many have used field data to argue for either a totally or partially ice-covered Earth, fewer efforts have been made to establish the basic physical climate state and internal dynamics of these alternatives. Description of feedbacks is especially important: how does a globally ice-covered Earth reinforce itself as a stable climate system, and/or sow the seeds for its own destruction? In previous work, we investigated the flow properties of thick floating global ice sheets, and found that flow from pole to equator tends to eliminate regions of thin ice in the tropics. We briefly mentioned that ice flow and sublimation could lead to a "lag deposit" of dust on top of the tropical ice. The consequences of this were explored in detail by Dorian Abbott and others, who found that the accumulation of dust atop tropical ice causes a strong warming effect, which strongly promotes deglaciation of a Snowball climate. However, Abbott et al specified a dust layer ab initio in their GCM simulations, leaving aside the processes which produce it. Here, we present the results of our efforts to add dust processes to an earlier coupled atmosphere/ocean/ice model originally developed by David Pollard and Jim Kasting. Their model includes energy balance equations for the atmosphere and an ice mechanics model for glacial flow. To this we have added variables tracking the fraction of dust incorporated into snow and ice; the transport and accumulation of this dust through ice flow; the effects of dust on albedo and penetration of sunlight into the ice; restriction of evaporation from dust-covered surfaces; and density and buoyancy effects of dusty ice. Dust is added to the surface globally at a fixed rate, and is removed by meltwater runoff. We find that ice in tropical regions of net evaporation quickly develops a surface dust layer which drastically lowers its albedo. This dust layer develops rapidly (1000-10,000 years), and remains relatively thin (mm to cm). Its albedo effect is not strong enough to cause deglaciation on its own, but does warm the planet to near the melting point: modest amounts of CO2 are enough to cause total deglaciation. Our results show that the "mudball Earth" is a remarkably stable climate system. Drastic changes in forcing, such as varying the rate of dust accumulation by a factor of 100, have little effect on the climate, due to a strong feedback control. With summertime temperatures just below melting, adding more dust to lower the planetary albedo warms the Earth, causing summertime melting which washes away the additional dust, maintaining status quo. Dust layer thickness is controlled by a related hydrological feedback: if the dust becomes thick enough to prevent evaporation in the tropics, then less snow falls at midlatitudes. Thus, midlatitude snow cover becomes dustier and darker, warming the planet, which again melts some ice to eliminate excess dust. Future work with this model will consider the patchiness of thin dust cover on an ice surface, and will also look at the consequences of large instantaneous dust sources such as asteroid/comet impacts or large volcanic eruptions.

Laboratory study of hyper-elocity impact-driven chemical reactions and surface evolution in icy targets.

NASA Astrophysics Data System (ADS)

Ulibarri, Z.; Munsat, T.; Dee, R.; Horanyi, M.; James, D.; Kempf, S.; Nagle, M.; Sternovsky, Z.

2017-12-01

Although ice is prevalent in the solar system and the long-term evolution of many airless icy bodies is affected by hypervelocity micrometeoroid bombardment, there has been little experimental investigation into these impact phenomena, especially at the impact speeds encountered in space. For example, there is little direct information about how dust impacts alter the local chemistry, and dust impacts may be an important mechanism for creating complex organic molecules necessary for life. Laser ablation and light-gas gun experiments simulating dust impacts have successfully created amino acid precursors from base components in ice surfaces. Additionally, the Cassini mission revealed CO2 deposits in icy satellites of Saturn, which may have been created by dust impacts. With the creation of a cryogenically cooled ice target for the dust accelerator facility at the NASA SSERVI-funded Institute for Modeling Plasma, Atmospheres, and Cosmic Dust (IMPACT), it is now possible to study the effects of micrometeoroid impacts in a controlled environment under conditions and at energies typically encountered in nature. Complex ice-target mixtures are created with a flash-freezing target which allows for homogeneous mixtures to be frozen in place even with salt mixtures that otherwise would form inhomogeneous ice surfaces. Coupled with the distinctive capabilities of the IMPACT dust facility, highly valuable data concerning the evolution of icy bodies under hypervelocity bombardment and the genesis of complex organic chemistry on these icy bodies can be gathered in unique and tightly controlled experiments. Results from recent and ongoing investigations will be presented.

Indoor air pollution: Acute adverse health effects and host susceptibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zummo, S.M.; Karol, M.H.

1996-01-01

Increased awareness of the poor quality of indoor air compared with outdoor air has resulted in a significant amount of research on the adverse health effects and mechanisms of action of indoor air pollutants. Common indoor air agents are identified, along with resultant adverse health effects, mechanisms of action, and likely susceptible populations. Indoor air pollutants range from biological agents (such as dust mites) to chemical irritants (such as nitrogen dioxide, carbon monoxide, sulfur dioxide, formaldehyde, and isocyanates). These agents may exert their effects through allergic as well as nonallergic mechanisms. While the public does not generally perceive poor indoormore » air quality as a significant health risk, increasing reports of illness related to indoor air and an expanding base of knowledge on the health effects of indoor air pollution are likely to continue pushing the issue to the forefront.« less

An Evaluation of an Aftermarket Local Exhaust Ventilation Device for Suppressing Respirable Dust and Respirable Crystalline Silica Dust from Powered Saws

PubMed Central

Garcia, Alberto; Jones, Erica; Echt, Alan S.; Hall, Ronald M.

2015-01-01

The objective of this study was to quantify the respirable dust and respirable silica exposures of roofing workers using an electric powered circular saw with an aftermarket local exhaust ventilation attachment to cut concrete roofing tiles. The study was conducted to determine whether the local exhaust ventilation attachment was able to control respirable dust and respirable silica exposure below occupational exposure limits. Time-integrated filter samples and direct reading respirable dust concentrations were evaluated. The local exhaust ventilation consisted of a shroud attached to the cutting plane of the saw; the shroud was then connected to a small electric axial fan, which is intended to collect dust at the point of generation. All sampling was conducted with the control in use. Roofers are defined as those individuals who solely lay tiles. Cutters/roofers are defined as those workers who operate the powered saw to cut tiles and also lay tiles. Respirable dust from this evaluation ranged from 0.13 to 6.59 milligrams per cubic meter (mg/m3) with a geometric mean of 0.38 mg/m3 for roofers and from 0.45 to 3.82 mg/m3 with a geometric mean of 1.84 mg/m3 for cutters/roofers. Cutters/roofers usually handle areas close to crevices, edges, or tips of the roof whereas roofers handle areas where complete tiles can be placed. The respirable dust exposures for all cutters/roofers indicated concentrations exceeding the Occupational Safety and Health Administration’s (OSHA) permissible exposure limit (PEL) for respirable dust containing silica; it was also exceeded for some of the roofers. The respirable silica concentrations ranged from 0.04 to 0.15 mg/m3 with an average of 0.09 mg/m3 for roofers, and from 0.13 to 1.21 mg/m3 with an average of 0.48 mg/m3 for cutters/roofers. As with respirable dust, the respirable silica exposures to cutters/roofers were higher than the exposures for roofers. PMID:25148513

An evaluation of an aftermarket local exhaust ventilation device for suppressing respirable dust and respirable crystalline silica dust from powered saws.

PubMed

Garcia, Alberto; Jones, Erica; Echt, Alan S; Hall, Ronald M

2014-01-01

The objective of this study was to quantify the respirable dust and respirable silica exposures of roofing workers using an electric-powered circular saw with an aftermarket local exhaust ventilation attachment to cut concrete roofing tiles. The study was conducted to determine whether the local exhaust ventilation attachment was able to control respirable dust and respirable silica exposure below occupational exposure limits (OELs). Time-integrated filter samples and direct reading respirable dust concentrations were evaluated. The local exhaust ventilation consisted of a shroud attached to the cutting plane of the saw; the shroud was then connected to a small electric axial fan, which is intended to collect dust at the point of generation. All sampling was conducted with the control in use. Roofers are defined as those individuals who only lay tiles. Cutters/roofers are defined as those workers who operate the powered saw to cut tiles and also lay tiles. Respirable dust from this evaluation ranged from 0.13 to 6.59 milligrams per cubic meter (mg/m(3)) with a geometric mean of 0.38 mg/m(3) for roofers and from 0.45 to 3.82 mg/m(3) with a geometric mean of 1.84 mg/m(3) for cutters/roofers. Cutters/roofers usually handle areas close to crevices, edges, or tips of the roof whereas roofers handle areas where complete tiles can be placed. The respirable dust exposures for all cutters/roofers indicated concentrations exceeding the Occupational Safety and Health Administration's (OSHA) permissible exposure limit (PEL) for respirable dust containing silica; it was also exceeded for some of the roofers. The respirable silica concentrations ranged from 0.04 to 0.15 mg/m(3) with a geometric mean of 0.09 mg/m(3) for roofers, and from 0.13 to 1.21 mg/m(3) with a geometric mean of 0.48 mg/m(3) for cutters/roofers. As with respirable dust, the respirable silica exposures for cutters/roofers were higher than the exposures for roofers.

Investigations of Desert Dust and Smoke in the North Atlantic in Support of the TOMS Instrument

NASA Technical Reports Server (NTRS)

Toon, Owen B.

2005-01-01

During the initial period of the work we concentrated on Saharan dust storms and published a sequence of papers (Colarco et a1 2002,2003a,b, Toon, 2004). The U.S. Air Force liked the dust model so well that they appropriated it for operational dust storm forecasting (Barnum et al., 2004). The Air Force has used it for about 5 yrs in the Middle East where dust storms cause significant operational problems. The student working on this project, Peter Colarco, has graduated and is now a civil servant at Goddard where he continues to interact with the TOMS team. This work helped constrain the optical properties of dust at TOMS wavelengths, which is useful for climate simulations and for TOMS retrievals of dust properties such as optical depth. We also used TOMS data to constrain the sources of dust in Africa and the Middle East, to determine the actual paths taken by Saharan dust storms, to learn more about the mechanics of variations in the optical depths, and to learn more about the mechanisms controlling the altitudes of the dust. During the last two years we have been working on smoke from fires. Black carbon aerosols are one of the leading factors in radiative forcing. The US Climate Change Science Program calls this area out for specific study. It has been suggested by Jim Hansen, and Mark Jacobsen among others, that by controlling emissions of black carbon we might reduce greenhouse radiative forcing in a relatively painless manner. However, we need a greatly improved understanding of the amount of black carbon in the atmosphere, where it is located, where it comes from, how it is mixed with other particles, what its actual optical properties are, and how it evolves. In order to learn about these issues we are using a numerical model of smoke. We have applied this model to the SAFARI field program data, and used the TOMS satellite observations in that period (Sept. 2000). Our goal is to constrain source function estimates for black carbon, and smoke optical properties.

Bladder cancer and occupational exposure to leather.

PubMed Central

Marrett, L D; Hartge, P; Meigs, J W

1986-01-01

A large case-control study of bladder cancer (2982 cases; 5782 controls) included information about occupational exposure to leather. Occupational histories of exposed white study subjects were reviewed and 150 were determined to have had "true" on the job exposure to leather. The odds ratio estimate (OR) of bladder cancer associated with such exposure in white subjects (n = 8063) was 1.4 (95% confidence limits = 1.0, 1.9) after adjustment for sex, age, and cigarette smoking. The risk was highest in those first employed in a leather job before 1945, although no dose-response relation with duration of leather employment was found. Subjects employed in "dusty" leather jobs had a slightly higher risk than those with other types of leather jobs. Our results are consistent with reports of an increased risk of bladder cancer associated with exposure to leather. Although the agents responsible have not been identified, our findings of an increased risk associated with exposure in the earlier years of this century and in dusty jobs suggest that leather dusts may be important. PMID:3947575

Monitoring and reducing exposure of infants to pollutants in house dust.

PubMed

Roberts, John W; Wallace, Lance A; Camann, David E; Dickey, Philip; Gilbert, Steven G; Lewis, Robert G; Takaro, Tim K

2009-01-01

The health risks to babies from pollutants in house dust may be 100 times greater than for adults. The young ingest more dust and are up to ten times more vulnerable to such exposures. House dust is the main exposure source for infants to allergens, lead, and PBDEs, as well as a major source of exposure to pesticides, PAHs, Gram-negative bacteria, arsenic, cadmium, chromium, phthalates, phenols, and other EDCs, mutagens, and carcinogens. Median or upper percentile concentrations in house dust of lead and several pesticides and PAHs may exceed health-based standards in North America. Early contact with pollutants among the very young is associated with higher rates of chronic illness such as asthma, loss of intelligence, ADHD, and cancer in children and adults. The potential of infants, who live in areas with soil contaminated by automotive and industrial emissions, can be given more protection by improved home cleaning and hand washing. Babies who live in houses built before 1978 have a prospective need for protection against lead exposures; homes built before 1940 have even higher lead exposure risks. The concentration of pollutants in house dust may be 2-32 times higher than that found in the soil near a house. Reducing infant exposures, at this critical time in their development, may reduce lifetime health costs, improve early learning, and increase adult productivity. Some interventions show a very rapid payback. Two large studies provide evidence that home visits to reduce the exposure of children with poorly controlled asthma triggers may return more than 100% on investment in 1 yr in reduced health costs. The tools provided to families during home visits, designed to reduce dust exposures, included vacuum cleaners with dirt finders and HEPA filtration, allergy control bedding covers, high-quality door mats, and HEPA air filters. Infants receive their highest exposure to pollutants in dust at home, where they spend the most time, and where the family has the most mitigation control. Normal vacuum cleaning allows deep dust to build up in carpets where it can be brought to the surface and become airborne as a result of activity on the carpet. Vacuums with dirt finders allow families to use the three-spot test to monitor deep dust, which can reinforce good cleaning habits. Motivated families that receive home visits from trained outreach workers can monitor and reduce dust exposures by 90% or more in 1 wk. The cost of such visits is low considering the reduction of risks achieved. Improved home cleaning is one of the first results observed among families who receive home visits from MHEs and CHWs. We believe that proven intervention methods can reduce the exposure of infants to pollutants in house dust, while recognizing that much remains to be learned about improving the effectiveness of such methods.

Sorption of Organophosphorus Flame Retardants (OPFRs) on ...

EPA Pesticide Factsheets

Organophosphorus flame retardants (OPFRs) are widely used as additives in industrial and consumer products such as electrical and electronic products, furniture, plastics, textiles, and building/construction materials. Due to human exposure and potential health effects, OPFRs including tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP), and tris(1,3-dichloro-2-propyl) phosphate (TDCPP) are EPA Action Plan chemicals for chemical assessments under the Toxic Substances Control Act (TSCA). This work investigated the sorption of these three compounds from the air to settled Arizona Test Dust (ATD) and house dust (HD) in a dual small chamber system. The OPFR exposed dust was analyzed to determine the sorption concentration and sorption rate of OPFRs on the dust. The effect of the composition of the dust on OPFR sorption was evaluated. The results showed that ATD and HD have varied sorption capacity for OPFRs from air. This work explores the relationship between OPFR concentrations in settled dust and air. The data can be used to determine partitioning of OPFRs between the gas phase and settled dust indoors and to inform strategies to reduce exposure and risk.

Persistent Organic Pollutants in Dust From Older Homes: Learning From Lead

PubMed Central

Metayer, Catherine; Ward, Mary H.; Colt, Joanne S.; Gunier, Robert B.; Deziel, Nicole C.; Rappaport, Stephen M.; Buffler, Patricia A.

2014-01-01

Objectives. We aimed to (1) evaluate the relation between home age and concentrations of multiple chemical contaminants in settled dust and (2) discuss the feasibility of using lead hazard controls to reduce children’s exposure to persistent organic pollutants. Methods. As part of the California Childhood Leukemia Study, from 2001 to 2007, we used a high-volume small surface sampler and household vacuum cleaners to collect dust samples from 583 homes and analyzed the samples for 94 chemicals with gas chromatography–mass spectrometry and inductively coupled plasma mass spectrometry. We evaluated relations between chemical concentrations in dust and home age with Spearman rank correlation coefficients. Results. Dust concentrations of lead, polychlorinated biphenyls, organochlorine insecticides, and polycyclic aromatic hydrocarbons were correlated with home age (ρ > 0.2; P < .001), whereas concentrations of pyrethroid insecticides and polybrominated diphenyl ethers were not. Conclusions. Dust in older homes contains higher levels of multiple, persistent chemicals than does dust in newer homes. Further development of strategies to reduce chemical exposures for children living in older homes is warranted. PMID:24832145

The effectiveness of handheld ventilated sanders in reducing inhalable dust concentrations.

PubMed

Carlton, Gary N; Patel, Kalpesh B; Johnson, David L; Hall, Thomas A

2003-01-01

Ventilated sanders are commonly used during aircraft surface abrasion but there is limited data on their effectiveness in reducing worker exposures. This study compared two handheld ventilated sander brands, DCM and Dynabrade, in a laboratory glovebox. Both sanders collect particulates by drawing air through holes in the sanding pads; the dust subsequently passes into a vacuum collection system. Aluminum panels coated with aircraft epoxy primer and polyurethane paint were abraded and inhalable dust concentrations were measured inside the glovebox with IOM samplers. The results indicate that both sanders effectively control inhalable dust, with the DCM sander reducing mass concentrations by 93 percent, and the Dynabrade by 98 percent, when the ventilation system is used. The Dynabrade unit, however, was more aggressive and produced over four times as much dust per unit time as the DCM unit. In spite of this, the Dynabrade sander adequately collected this additional dust. Varying abrasive grit size did not significantly affect dust generation, although the differences between the grit sizes used (180 and 240 grit) were not great and may have influenced the results.

Gene Expression Profiling in Lung Tissues from Rat Exposed to Lunar Dust Particles

NASA Technical Reports Server (NTRS)

Zhang, Ye; Lam, Chiu-Wing; Zalesak, Selina M.; Kidane, Yared H.; Feiveson, Alan H.; Ploutz-Snyder, Robert; Scully, Robert R.; Williams, Kyle; Wu, Honglu; James, John T.

2014-01-01

The Moon's surface is covered by a layer of fine, reactive dust. Lunar dust contain about 1-2% of very fine dust (< 3 micron), that is respirable. The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to analyze the dynamics of global gene expression changes in lung tissues from rats exposed to lunar dust particles. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose-only inhalation chambers to concentrations of 0 (control air), 2.1, 6.8, 21, and 61 mg/m(exp 3) of lunar dust. Five rats per group were euthanized 1 day, and 3 months after the last inhalation exposure. The total RNAs were isolated from lung tissues after being lavaged. The Agilent Rat GE v3 microarray was used to profile global gene expression (44K). The genes with significant expression changes are identified and the gene expression data were further analyzed using various statistical tools.

A survey of spatially distributed exterior dust lead loadings in New York City

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caravanos, Jack; Weiss, Arlene L.; School of Medicine, New York University, NY 10016

This work documents ambient lead dust deposition values (lead loading) for the boroughs of New York City in 2003-2004. Currently, no regulatory standards exist for exterior concentrations of lead in settled dust. This is in contrast to the clearance and risk assessment standards that exist for interior residential dust. The reported potential for neurobehavioral toxicity and adverse cognitive development in children due to lead exposure prompts public health concerns about undocumented lead sources. Such sources may include settled dust of outdoor origin. Dust sampling throughout the five boroughs of NYC was done from the top horizontal portion of pedestrian trafficmore » control signals (PTCS) at selected street intersections along main thoroughfares. The data (n=214 samples) show that lead in dust varies within each borough with Brooklyn having the highest median concentration (730{mu}g/ft{sup 2}), followed in descending order by Staten Island (452{mu}g/ft{sup 2}), the Bronx (382{mu}g/ft{sup 2}), Queens (198{mu}g/ft{sup 2}) and finally, Manhattan (175{mu}g/ft{sup 2}). When compared to the HUD/EPA indoor lead in dust standard of 40{mu}g/ft{sup 2}, our data show that this value is exceeded in 86% of the samples taken. An effort was made to determine the source of the lead in the dust atop of the PTCS. The lead in the dust and the yellow signage paint (which contains lead) were compared using isotopic ratio analysis. Results showed that the lead-based paint chip samples from intact signage did not isotopically match the dust wipe samples taken from the same surface. We know that exterior dust containing lead contributes to interior dust lead loading. Therefore, settled leaded dust in the outdoor environment poses a risk for lead exposure to children living in urban areas, namely, areas with elevated childhood blood lead levels and background lead dust levels from a variety of unidentified sources.« less

Work-related symptoms and dose-response relationships for personal exposures and pulmonary function among woodworkers.

PubMed

Mandryk, J; Alwis, K U; Hocking, A D

1999-05-01

Four sawmills, a wood chipping mill, and five joineries in New South Wales, Australia, were studied for the effects of personal exposure to wood dust, endotoxins. (1-->3)-beta-D-glucans, Gram-negative bacteria, and fungi on lung function among woodworkers. Personal inhalable and respirable dust sampling was carried out. The lung function tests of workers were conducted before and after a workshift. The mean percentage cross-shift decrease in lung function was markedly high for woodworkers compared with the controls. Dose-response relationships among personal exposures and percentage cross-shift decrease in lung function and percentage predicted lung function were more pronounced among joinery workers compared with sawmill and chip mill workers. Woodworkers had markedly high prevalence of regular cough, phlegm, and chronic bronchitis compared with controls. Significant associations were found between percentage cross-shift decrease in FVC and regular phlegm and blocked nose among sawmill and chip mill workers. Both joinery workers and sawmill and chip mill workers showed significant relationships between percentage predicted lung function (FVC, FEV1, FEV1/FVC, FEF25-75%) and respiratory symptoms. Wood dust and biohazards associated with wood dust are potential health hazards and should be controlled.

40 CFR 745.90 - Renovator certification and dust sampling technician certification.

Code of Federal Regulations, 2014 CFR

2014-07-01

... AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN... certified renovator. (3) Individuals who have successfully completed an accredited lead-based paint... are currently certified as lead-based paint inspectors or risk assessors may act as certified dust...

40 CFR 745.90 - Renovator certification and dust sampling technician certification.

Code of Federal Regulations, 2013 CFR

2013-07-01

... AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN... certified renovator. (3) Individuals who have successfully completed an accredited lead-based paint... are currently certified as lead-based paint inspectors or risk assessors may act as certified dust...

40 CFR 745.90 - Renovator certification and dust sampling technician certification.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN... certified renovator. (3) Individuals who have successfully completed an accredited lead-based paint... are currently certified as lead-based paint inspectors or risk assessors may act as certified dust...

Dose response effect of cement dust on respiratory muscles competence in cement mill workers.

PubMed

Meo, Sultan A; Azeem, Muhammad A; Qureshi, Aijaz A; Ghori, G Moinudin; Al-Drees, Abdul Majeed; Feisal Subhan, Mirza Muhammad

2006-12-01

Electromyography (EMG) of respiratory muscles is a reliable method of assessing the ventilatory muscle function, but still its use has not been fully utilized to determine the occupational and environmental hazards on respiratory muscles. Therefore, EMG of intercostal muscles was performed to determine the dose response effect of cement dust on respiratory muscles competence. Matched cross-sectional study of EMG in 50 non-smoking cement mill workers with an age range of 20 - 60 years, who worked without the benefit of cement dust control ventilation or respiratory protective devices. EMG was performed by using surface electrodes and chart recorder. Significant reduction was observed in number of peaks (p < 0.0005), maximum peak amplitude (p < 0.0005), peak-to-peak amplitude (p < 0.0005) and duration of response (p < 0.0005) in cement mill workers compared to their matched control. Cement dust impairs the intercostal muscle competence and stratification of results shows a dose-effect of years of exposure in cement mill.

Effect of manual feeding on the level of farmer's exposure to airborne contaminants in the confinement nursery pig house.

PubMed

Kim, Ki-Youn; Ko, Han-Jong; Kim, Hyeon-Tae; Kim, Chi-Nyon; Kim, Yoon-Shin; Roh, Young-Man

2008-04-01

The objective of the study is to demonstrate an effect of manual feeding on the level of farmer's exposure to airborne contaminants in the confinement nursery pig house. The levels of all the airborne contaminants besides respirable dust, total airborne fungi and ammonia were significantly higher in the treated nursery pig house with feeding than the control nursery pig house without feeding. Although there is no significant difference in respirable dust and total airborne fungi between the treatment and the control, their concentrations in the treated nursery pig house were also higher than the control nursery pig house. The result that the level of ammonia in the treated nursery pig house is lower than the control nursery pig house would be reasoned by the mechanism of ammonia generation in the pig house and adsorption property of ammonia to dust particles. In conclusion, manual feeding by farmer increased the exposure level of airborne contaminants compared to no feeding activity.

Possible influence of dust on hurricane genesis

NASA Astrophysics Data System (ADS)

Bretl, Sebastian; Reutter, Philipp; Raible, Christoph C.; Ferrachat, Sylvaine; Lohmann, Ulrike

2014-05-01

Tropical Cyclones (TCs) belong to the most extreme events in nature. In the past decade, the possible impact of dust on Atlantic hurricanes receives growing interest. As mineral dust is able to absorb incoming solar radiation and therefore warm the surrounding air, the presence of dust can lead to a reduction of sea surface temperature (SST) and an increase in atmospheric stability. Furthermore, resulting baroclinic effects and the dry Saharan easterly jet lead to an enhanced vertical shear of the horizontal winds. SST, stability, moisture and vertical wind shear are known to potentially impact hurricane activity. But how Saharan dust influences these prerequisites for hurricane formation is not yet clear. Some dynamical mechanisms induced by the SAL might even strengthen hurricanes. An adequate framework for investigating the possible impact of dust on hurricanes is comparing high resolution simulations (~0.5°x0.5°, 31 vertical levels) with and without radiatively active dust aerosols. To accomplish this task, we are using the general circulation model ECHAM6 coupled to a modified version of the aerosol model HAM, ECHAM6-HAM-Dust. Instead of the five aerosol species HAM normally contains, the modified version takes only insoluble dust into account, but modifies the scavenging parameters in order to have a similar lifetime of dust as in the full ECHAM6-HAM. All remaining aerosols are prescribed. To evaluate the effects of dust on hurricanes, a TC detection and tracking method is applied on the results. ECHAM6-HAM-Dust was used in two configurations, one with radiatively active dust aerosols and one with dust being not radiatively active. For both set-ups, 10 Monte-Carlo simulations of the year 2005 were performed. A statistical method which identifies controlling parameters of hurricane genesis was applied on North Atlantic developing and non-developing disturbances in all simulations, comparing storms in the two sets of simulations. Hereby, dust can be assigned a more influencing role on TC genesis in the simulations with active dust. Despite dust is seeming to have a negative influence on TC genesis, the relative importance of dust compared to the sea surface temperature (SST) cannot be determined thoroughly. This is largely due to a similar pattern of SST and dust off the west coast of Africa, so that possible effects of dust and SST could hardly be separated.

COPD and occupational exposures: a case-control study.

PubMed

Weinmann, Sheila; Vollmer, William M; Breen, Victor; Heumann, Michael; Hnizdo, Eva; Villnave, Jacqueline; Doney, Brent; Graziani, Monica; McBurnie, Mary Ann; Buist, A Sonia

2008-05-01

Evidence demonstrates that occupational exposures are causally linked with chronic obstructive pulmonary disease (COPD). This case-control study evaluated the association between occupational exposures and prevalent COPD based on lifetime occupational history. Cases (n = 388) aged 45 years and older with COPD were compared with controls (n = 356), frequency matched on age, sex, and cigarette smoking history. Odds ratios for exposure to each of eight occupational hazard categories and three composite measures of exposure were computed using logistic regression. RESULTSOccupational exposures most strongly associated with COPD were diesel exhaust, irritant gases and vapors, mineral dust, and metal dust. The composite measures describing aggregate exposure to gases, vapors, solvents, or sensitizers (GVSS) and aggregate exposure to dust, GVSS, or diesel exhaust were also associated with COPD. In the small group of never-smokers, a similar pattern was evident. These population-based findings add to the literature linking occupational exposures to COPD.

Concentrations of Surface-Dust Metals in Native American Jewelry-Making Homes in Zuni Pueblo, New Mexico

PubMed Central

Gonzales, Melissa; Shah, Vallabh; Bobelu, Arlene; Qualls, Clifford; Natachu, Kathy; Bobelu, Jeanette; Jamon, Eunice; Neha, Donica; Paine, Susan; Zager, Philip

2013-01-01

This pilot study was conducted to identify the metals used by home-based Native American jewelry makers, to quantify the metals in dust samples taken from jewelers’ homes, and to compare these concentrations with background levels from control homes in which jewelry was not made. Participants were recruited from Zuni Pueblo, New Mexico. Surface dust samples were collected from the work and living areas of 20 jewelers’ homes, and from the living areas of 20 control homes. Silver, copper, tin, boron, nickel, zinc, lead, and cadmium were significantly higher in work areas than in living areas of jewelry-making homes (p≤ 0.02). Silver, copper, nickel, and antimony were significantly higher in living areas of jewelers’ homes compared with control homes (p ≤ 0.04). Ventilation measures did not effectively reduce metal concentrations in jewelers’ homes; concentrations in nonwork areas remained elevated. PMID:16201670

Effects of Heavy Metals from Soil and Dust Source on DNA Damage of the Leymus chinensis Leaves in Coal-Mining Area in Northwest China

PubMed Central

Li, Tianxin; Zhang, Minjie; Lu, Zhongming; Herman, Uwizeyimana; Mumbengegwi, Dzivaidzo; Crittenden, John

2016-01-01

Air and soil pollution from mining activities has been considered as a critical issue to the health of living organisms. However, few efforts have been made in distinguishing the main pathway of organism genetic damage by heavy metals related to mining activities. Therefore, we investigated the genetic damage of Leymus chinensis leaf cells, the air particulate matter (PM) contents, and concentrations of the main heavy metals (Pb, Cd, Cr, Hg) in soil and foliar dust samples collected from seven experiment points at the core mining area and one control point 20 kilometers away from the core mining area in Inner Mongolia in 2013. Comet assay was used to test the genetic damage of the Leymus chinensis leaf cells; the Tail DNA% and Tail Moment were used to characterize the genetic damage degree of the plant cells. The comet assay results showed that the cell genetic damage ratio was up to 77.0% in experiment points but was only 35.0% in control point. The control point also had the slight Tail DNA% and Tail Moment values than other experiment groups. The cell damage degree of the control group was 0.935 and experiment groups were 1.299–1.815. The geo-accumulation index and comperehensive pollution index(CPI) were used to characterize heavy metal pollution in foliar dust samples, and single factor pollution index and CPI were used to characterize the heavy metal pollution in soil samples. The CPIfoliar dust of control group was 0.36 and experiment groups were 1.45–2.57; the CPIsoil of control group was 0.04 and experiment groups were 0.07–0.12. The results of correlation analyze showed that Air Quality Index (AQI) -CPIfoliar dust(r = 0.955**)>Damage degree-CPIfoliar dust(r = 0.923**)>Damage degree-AQI(r = 0.908**)>Damage degree-CPIsoil (r = 0.824*). The present research proved that mining activity had a high level of positive correlation with organism genetic damage caused by heavy metals through comparing with the control point; soil and atmosphere were both the important action pathway for heavy metal induced genetic damage in mining area. Furthermore, heavy metal contents in foliar dust showed a higher positive correlation with genetic damage than when compared with soil. This means the heavy metal contents that L.chinensis absorbed through respiration from the atmosphere could make more serious genetic damage than when absorbed by root systems from soil in the mining area. This study can provide theoretical support for research on plant genetic damage mechanisms and exposure pathways induced by environmental pollution. PMID:27935969

Effects of Heavy Metals from Soil and Dust Source on DNA Damage of the Leymus chinensis Leaves in Coal-Mining Area in Northwest China.

PubMed

Li, Tianxin; Zhang, Minjie; Lu, Zhongming; Herman, Uwizeyimana; Mumbengegwi, Dzivaidzo; Crittenden, John

2016-01-01

Air and soil pollution from mining activities has been considered as a critical issue to the health of living organisms. However, few efforts have been made in distinguishing the main pathway of organism genetic damage by heavy metals related to mining activities. Therefore, we investigated the genetic damage of Leymus chinensis leaf cells, the air particulate matter (PM) contents, and concentrations of the main heavy metals (Pb, Cd, Cr, Hg) in soil and foliar dust samples collected from seven experiment points at the core mining area and one control point 20 kilometers away from the core mining area in Inner Mongolia in 2013. Comet assay was used to test the genetic damage of the Leymus chinensis leaf cells; the Tail DNA% and Tail Moment were used to characterize the genetic damage degree of the plant cells. The comet assay results showed that the cell genetic damage ratio was up to 77.0% in experiment points but was only 35.0% in control point. The control point also had the slight Tail DNA% and Tail Moment values than other experiment groups. The cell damage degree of the control group was 0.935 and experiment groups were 1.299-1.815. The geo-accumulation index and comperehensive pollution index(CPI) were used to characterize heavy metal pollution in foliar dust samples, and single factor pollution index and CPI were used to characterize the heavy metal pollution in soil samples. The CPIfoliar dust of control group was 0.36 and experiment groups were 1.45-2.57; the CPIsoil of control group was 0.04 and experiment groups were 0.07-0.12. The results of correlation analyze showed that Air Quality Index (AQI) -CPIfoliar dust(r = 0.955**)>Damage degree-CPIfoliar dust(r = 0.923**)>Damage degree-AQI(r = 0.908**)>Damage degree-CPIsoil (r = 0.824*). The present research proved that mining activity had a high level of positive correlation with organism genetic damage caused by heavy metals through comparing with the control point; soil and atmosphere were both the important action pathway for heavy metal induced genetic damage in mining area. Furthermore, heavy metal contents in foliar dust showed a higher positive correlation with genetic damage than when compared with soil. This means the heavy metal contents that L.chinensis absorbed through respiration from the atmosphere could make more serious genetic damage than when absorbed by root systems from soil in the mining area. This study can provide theoretical support for research on plant genetic damage mechanisms and exposure pathways induced by environmental pollution.

Millennial-scale variations in dustiness recorded in Mid-Atlantic sediments from 0 to 70 ka

NASA Astrophysics Data System (ADS)

Middleton, Jennifer L.; Mukhopadhyay, Sujoy; Langmuir, Charles H.; McManus, Jerry F.; Huybers, Peter J.

2018-01-01

Sedimentary records of dust deposition in the subtropical Atlantic provide important constraints on millennial- and orbital-scale variability in atmospheric circulation and North African aridity. Constant flux proxies, such as extraterrestrial helium-3, yield dust flux records that are independent of the biases caused by lateral sediment transport and limited resolution that may be associated with age-model-derived mass accumulation rates. However, Atlantic dust records constrained using constant flux proxies are sparsely distributed and generally limited to the past 20 ka. Here we extend the Atlantic record of North African dust deposition to 70 ka using extraterrestrial helium-3 and measurements of titanium, thorium, and terrigenous helium-4 in two sediment cores collected at 26°N and 29°N on the Mid-Atlantic Ridge and compare results to model estimates for dust deposition in the subtropical North Atlantic. Dust proxy fluxes between 26°N and 29°N are well correlated, despite variability in lateral sediment transport, and underscore the utility of extraterrestrial helium-3 for constraining millennial-scale variability in dust deposition. Similarities between Mid-Atlantic dust flux trends and those observed along the Northwest African margin corroborate previous interpretations of dust flux variability over the past 20 ka and suggest that long distance transport and depositional processes do not overly obscure the signal of North African dust emissions. The 70 ka Mid-Atlantic record reveals a slight increase in North African dustiness from Marine Isotope Stage 4 through the Last Glacial Maximum and a dramatic decrease in dustiness associated with the African Humid Period. On the millennial-scale, the new records exhibit brief dust maxima coincident with North Atlantic cold periods such as the Younger Dryas, and multiple Heinrich Stadials. The correlation between Mid-Atlantic dust fluxes and previous constraints on North African aridity is high. However, precipitation exerts less control on dust flux variability prior to the African Humid Period, when wind variability governs dust emissions from consistently dry dust source regions. Thus, the Mid-Atlantic dust record supports the hypothesis that both aridity and wind strength drive dust flux variability across changing climatic conditions.

ARC-2005-ACD05-0022-025

NASA Image and Video Library

2005-02-04

Ames Mars Wind Tunnel Facility N-245: NASA is simulating small martian 'dust devils' and wind in a laboraotry to determine how they may affect the landscape and environment of the red planet. Dust Devils on Mars are often a great deal biggger than those on Earth and can at times cover the whole planet. Martian winds & dust devils, big and little, collectively are a great force that is constantly changing the planet's environment. shown here: is the control room for the Mars W.T. with Eric Eddlemon

Cholinesterase activity in Japanese quail dusted with carbaryl

USGS Publications Warehouse

Hill, E.F.

1979-01-01

Japanese quail (Coturnix coturnix japonica) were dusted with 5% carbaryl to determine if this topical treatment would alter plasma and brain cholinesterase activities. Within 6 hours after dusting, plasma cholinesterase activity was depressed compared with controls, the depression averaging 20% for females and 27% for males. By 24 hours the cholinesterase activity of females had returned to normal, but the cholinesterase activity of males remained depressed. Brain cholinesterase activity was not affected by the treatment, and there were no overt toxic signs.

Mechanisms and causes of wear in tooth enamel: implications for hominin diets.

PubMed

Lucas, Peter W; Omar, Ridwaan; Al-Fadhalah, Khaled; Almusallam, Abdulwahab S; Henry, Amanda G; Michael, Shaji; Thai, Lidia Arockia; Watzke, Jörg; Strait, David S; Atkins, Anthony G

2013-03-06

The wear of teeth is a major factor limiting mammalian lifespans in the wild. One method of describing worn surfaces, dental microwear texture analysis, has proved powerful for reconstructing the diets of extinct vertebrates, but has yielded unexpected results in early hominins. In particular, although australopiths exhibit derived craniodental features interpreted as adaptations for eating hard foods, most do not exhibit microwear signals indicative of this diet. However, no experiments have yet demonstrated the fundamental mechanisms and causes of this wear. Here, we report nanowear experiments where individual dust particles, phytoliths and enamel chips were slid across a flat enamel surface. Microwear features produced were influenced strongly by interacting mechanical properties and particle geometry. Quartz dust was a rigid abrasive, capable of fracturing and removing enamel pieces. By contrast, phytoliths and enamel chips deformed during sliding, forming U-shaped grooves or flat troughs in enamel, without tissue loss. Other plant tissues seem too soft to mark enamel, acting as particle transporters. We conclude that dust has overwhelming importance as a wear agent and that dietary signals preserved in dental microwear are indirect. Nanowear studies should resolve controversies over adaptive trends in mammals like enamel thickening or hypsodonty that delay functional dental loss.

Pulmonary functions in tannery workers--a cross sectional study.

PubMed

Chandrasekaran, Vasanthi; Dilara, K; Padmavathi, R

2014-01-01

Tannery workers are at potential exposure to detrimental agents rendering them vulnerable to respiratory and dermal problems. Thus by performing pulmonary functions among leather tannery workers, we can decipher the effect of chromium and leather dust on lung functions and also the decline of respiratory functions with increasing years of exposure to leather dust. Pulmonary functions were assessed for 130 tannery workers and compared with the 130 unexposed office workers. Pulmonary function measurements namely FVC, FEV1, FEF25-75% and PEFR were measured using portable data logging Spirometer (KOKO Spirometer). The observed pulmonary functions of Tannery-workers in this study showed a reduction in FEV1, FVC, FEV1/FVC ratio, FEF25-75 and PEFR in relation to their predicted values and also compared to the unexposed. Smokers showed a decline in pulmonary functions compared to the non smokers because smoking acts as an additional risk factor in the development of respiratory illnesses. It is worthy to mention that the pulmonary function values correlate negatively with the duration of exposure to leather dust. So this study could provide base line information based upon which legal implementation of preventive measures could be undertaken.

The Effects of Lunar Dust on EVA Systems During the Apollo Missions

NASA Technical Reports Server (NTRS)

Gaier, James R.

2005-01-01

Mission documents from the six Apollo missions that landed on the lunar surface have been studied in order to catalog the effects of lunar dust on Extra-Vehicular Activity (EVA) systems, primarily the Apollo surface space suit. It was found that the effects could be sorted into nine categories: vision obscuration, false instrument readings, dust coating and contamination, loss of traction, clogging of mechanisms, abrasion, thermal control problems, seal failures, and inhalation and irritation. Although simple dust mitigation measures were sufficient to mitigate some of the problems (i.e., loss of traction) it was found that these measures were ineffective to mitigate many of the more serious problems (i.e., clogging, abrasion, diminished heat rejection). The severity of the dust problems were consistently underestimated by ground tests, indicating a need to develop better simulation facilities and procedures.

The Effects of Lunar Dust on EVA Systems During the Apollo Missions

NASA Technical Reports Server (NTRS)

Gaier, James R.

2007-01-01

Mission documents from the six Apollo missions that landed on the lunar surface have been studied in order to catalog the effects of lunar dust on Extra-Vehicular Activity (EVA) systems, primarily the Apollo surface space suit. It was found that the effects could be sorted into nine categories: vision obscuration, false instrument readings, dust coating and contamination, loss of traction, clogging of mechanisms, abrasion, thermal control problems, seal failures, and inhalation and irritation. Although simple dust mitigation measures were sufficient to mitigate some of the problems (i.e., loss of traction) it was found that these measures were ineffective to mitigate many of the more serious problems (i.e., clogging, abrasion, diminished heat rejection). The severity of the dust problems were consistently underestimated by ground tests, indicating a need to develop better simulation facilities and procedures.

Utilization of ultrasonic atomization for dust control in underground mining

NASA Astrophysics Data System (ADS)

Okawa, Hirokazu; Nishi, Kentaro; Kawamura, Youhei; Kato, Takahiro; Sugawara, Katsuyasu

2017-07-01

This study examined dust suppression using water particles generated by ultrasonic atomization (2.4 MHz) at low temperature (10 °C). Green tuff (4 µm), green tuff (6 µm), kaolin, and silica were used as dust samples. Even though ultrasonic atomization makes fine water particles, raising relative air humidity immediately was difficult at low temperature. However, remaining water particles that did not change to water vapor contributed to suppression of dust dispersion. Additionally, the effect of water vapor amount (absolute humidity) and water particles generated by ultrasonic atomization on the amount of dust dispersion was investigated using experimental data at temperatures of 10, 20, and 30 °C. Utilization of ultrasound atomization at low temperature has the advantages of low humidity increments in the working space and water particles remaining stable even with low relative air humidity.

Effects of occupational exposure to noise and dust on blood pressure in Chinese industrial workers.

PubMed

Lin, Jingfeng; Wang, Hufei; Yan, Fen; Tang, Kefu; Zhu, Huang; Weng, Zuquan; Wang, Kejian

2018-01-01

Along with the rapid development of economy and urbanization, noise and air pollution are becoming major occupational health hazards in the process of industrial production. In this study, we collected data from 7293 industrial workers in China. The association between occupational exposure of noise and dust and blood pressure was investigated. Controlling for demographic variables, including sex, age, and length of service, a stepwise regression model with backward elimination was constructed. The results showed that both noise and dust decreased the level of systolic blood pressure (p < 0.001). This finding prompted the manufacturing industry to reduce noise and dust hazards and protect the occupational health of workers. Prospective studies in different populations are still required to verify the net contribution of noise and dust to the decrease in blood pressure.

Hospital admissions for asthma and acute bronchitis in El Paso, Texas: do age, sex, and insurance status modify the effects of dust and low wind events?

PubMed

Grineski, Sara E; Staniswalis, Joan G; Bulathsinhala, Priyangi; Peng, Yanlei; Gill, Thomas E

2011-11-01

El Paso County (Texas) is prone to still air inversions and is one of the dust "hot spots" in North America. In this context, we examined the sub-lethal effects of airborne dust and low wind events on human respiratory health (i.e., asthma and acute bronchitis) between 2000 and 2003, when 110 dust and 157 low wind events occurred. Because environmental conditions may not affect everyone the same, we explored the effects of dust and low wind within three age groups (children, adults, and the elderly), testing for effect modifications by sex and insurance status, while controlling for weather and air pollutants. We used a case-crossover design using events matched with referent days on the same day-of-the-week, month, and year with conditional logistic regression to estimate the probability of hospital admission, while controlling for apparent temperature (lag 1), nitrogen dioxide, and particulate matter of 2.5μm or less. Children (aged 1-17) were 1.19 (95% confidence interval: 1.00-1.41) times more likely to be hospitalized for asthma three days after a low wind event, and 1.33 (95% CI: 1.01-1.75) times more likely to be hospitalized for acute bronchitis one day after a dust event than on a clear day. Girls were more sensitive to acute bronchitis hospitalizations after dust events (1.83, 95% CI: 1.09-3.08) than boys, but less sensitive than boys to acute bronchitis hospitalizations after low wind events (0.68, 95% CI: 0.46-1.00). We found general trends with regard to dust and low wind events being associated with increased odds of hospitalization for asthma and bronchitis amongst all ages and adults (aged 18-64). Adults covered by Medicaid and adults without health insurance had higher risks of hospitalization for asthma and acute bronchitis after both low wind and dust events. Results suggest that there were respiratory health effects associated with dust and low wind events in El Paso, with stronger impacts among children and poor adults. Girls and boys with acute bronchitis were differentially sensitive to dust and low wind events. Copyright © 2011 Elsevier Inc. All rights reserved.

Phthalate concentrations in house dust in relation to autism spectrum disorder and developmental delay in the CHildhood Autism Risks from Genetics and the Environment (CHARGE) study.

PubMed

Philippat, Claire; Bennett, Deborah H; Krakowiak, Paula; Rose, Melissa; Hwang, Hyun-Min; Hertz-Picciotto, Irva

2015-06-26

Phthalates are endocrine-disrupting chemicals that influence thyroid hormones and sex steroids, both critical for brain development. We studied phthalate concentrations in house dust in relation to the risks of developing autism spectrum disorder (ASD) or developmental delay (DD). Participants were a subset of children from the CHARGE (CHildhood Autism Risks from Genetics and the Environment) case-control study. ASD and DD cases were identified through the California Department of Developmental Services system or referrals; general population controls were randomly sampled from state birth files and frequency-matched on age, sex, and broad geographic region to ASD cases. All children (50 ASD, 27 DD, 68 typically developing (TD)) were assessed with Mullen Scales of Early Learning, Vineland Adaptive Behavior Scales (VABS) and Aberrant Behavior Checklist. We measured 5 phthalates in dust collected in the child's home using a high volume small surface sampler. None of the phthalates measured in dust was associated with ASD. After adjustment, we observed greater di(2-ethylhexyl) phthalate (DEHP) and butylbenzyl phthalate (BBzP) concentrations in indoor dust from homes of DD children: Odds ratios (OR) were 2.10 (95% confidence interval (CI); 1.10; 4.09) and 1.40 (95% CI; 0.97; 2.04) for a one-unit increase in the ln-transformed DEHP and BBzP concentrations, respectively. Among TD children, VABS communication, daily living, and adaptive composite standard scores were lower, in association with increased diethyl phthalate (DEP) concentrations in dust. Participants with higher dibutyl phthalate (DBP) concentrations in house dust also trended toward reduced performance on these subscales. Among ASD and DD boys, higher indoor dust concentrations of DEP and DBP were associated with greater hyperactivity-impulsivity and inattention. House dust levels of phthalates were not associated with ASD. The inability to distinguish past from recent exposures in house dust and the fact that house dust does not capture exposure from all sources, limit the interpretation of both positive and null findings and further work is needed. However, the associations observed for DEP and DBP with impairments in several adaptive functions and greater hyperactivity, along with evidence for increased risk of DD raise concerns that these chemicals may affect neurodevelopment in children.

Alpine lakes preserve mineral dust signatures: Implications for long-range mineral dust transport and Last Glacial Maximum (LGM) tornado frequency in the United States

NASA Astrophysics Data System (ADS)

Bhattacharya, A.; Lora, J. M.; Pollen, A.; Vollmer, T.; Thomas, M.; Leithold, E. L.; Mitchell, J.; Tripati, A.

2016-12-01

The net amount of mineral dust accumulation in arid and semi-arid regions might not be entirely sourced locally or even regionally; in fact, new evidence suggests that there could be significant contributions from distal sources. The contribution from the distal sources needs to be identified, and accounted for, in order to accurately understand the meteorological and climatologic factors, both regional and global, that control mineral dust accumulation in arid and semi-arid regions. Most importantly, if identified, the two components of mineral dust accumulation- fine fraction (typically <4 microns) and coarse fraction (typically >25 microns)- could provide critical information about regional as well as global climate. There are large-scale climatological controls on the finer fraction of mineral dust, while the coarser fraction is related to intense invents (i.e., the occurrence of cyclones). However, studies attempting to separate these two size fractions in terrestrial archives have been limited. Here we separate the two size fractions using grain size analysis, and use trace element analysis in each size fraction to identify contributing source regions. We apply this technique to well-dated cores collected from three lakes that are distributed across the western, southwestern and Great Plains in the United States: Pear Lake in the Sierra Nevada Mountains (CA), Senator Beck Lake in the San Juan Mountains (CO), and North Lake (WY). These lakes are uniquely situated to monitor dust fluxes; previous studies have demonstrated that sedimentation in these lakes are dominated by mineral dust accumulation; there is also evidence of remotely and locally sourced dust in these lakes, and of textural differences between the two types of dust fractions. We compare our results with previously published data on dust from loess deposits in the United States, and isotopic modeling (LMDZ). We find evidence that the finer-grain size fraction in alpine lake cores could be of remote origin; work is underway to quantify this contribution. Most importantly, we find that during the Last Glacial Maximum (LGM) the Great Plains may not have witnessed an increase in the incidence of tornado frequency. Acknowledgements: James Sigman, Jacob Ashford, Jason Neff and Amato Evan

Hospital admissions for asthma and acute bronchitis in El Paso, Texas: Do age, sex, and insurance status modify the effects of dust and low wind events?

PubMed Central

Staniswalis, Joan G.; Bulathsinhala, Priyangi; Peng, Yanlei; Gill, Thomas E.

2013-01-01

Background El Paso County (Texas) is prone to still air inversions and is one of the dust “hot spots” in North America. In this context, we examined the sub-lethal effects of airborne dust and low wind events on human respiratory health (i.e., asthma and acute bronchitis) between 2000 and 2003, when 110 dust and 157 low wind events occurred. Because environmental conditions may not affect everyone the same, we explored the effects of dust and low wind within three age groups (children, adults, and the elderly), testing for effect modifications by sex and insurance status, while controlling for weather and air pollutants. Methods We used a case-crossover design using events matched with referent days on the same day-of-the-week, month, and year with conditional logistic regression to estimate the probability of hospital admission, while controlling for apparent temperature (lag 1), nitrogen dioxide, and particulate matter of 2.5 micrometers or less. Results Children (aged 1–17) were 1.19 (95% confidence interval: 1.00–1.41) times more likely to be hospitalized for asthma three days after a low wind event, and 1.33 (95% CI: 1.01–1.75) times more likely to be hospitalized for acute bronchitis one day after a dust event than on a clear day. Girls were more sensitive to acute bronchitis hospitalizations after dust events (1.83, 95% CI: 1.09–3.08) than boys, but less sensitive than boys to acute bronchitis hospitalizations after low wind events (0.68, 95% CI: 0.46–1.00). We found general trends with regard to dust and low wind events being associated with increased odds of hospitalization for asthma and bronchitis amongst all ages and adults (aged 18–64). Adults covered by Medicaid and adults without health insurance had higher risks of hospitalization for asthma and acute bronchitis after both low wind and dust event Conclusions Results suggest that there were respiratory health effects associated with dust and low wind events in El Paso, with stronger impacts among children and poor adults. Girls and boys with acute bronchitis were differentially sensitive to dust and low wind events. PMID:21782162

Iron dissolution kinetics of mineral dust at low pH during simulated atmospheric processing

NASA Astrophysics Data System (ADS)

Shi, Z.; Bonneville, S.; Krom, M. D.; Carslaw, K. S.; Jickells, T. D.; Baker, A. R.; Benning, L. G.

2010-11-01

We investigated the iron (Fe) dissolution kinetics of African (Tibesti) and Asian (Beijing) dust samples at acidic pH with the aim of reproducing the low pH conditions in atmospheric aerosols. The Beijing dust and three size fractions of the Tibesti dust (<20 μm: PM20; <10 μm: PM10; and <2.5 μm: PM2.5) were dissolved at pH 1, 2 and/or 3 for up to 1000 h. In the first 10 min, all dust samples underwent an extremely fast Fe solubilisation. Subsequently, the Fe dissolution proceeded at a much slower rate before reaching a stable dissolution plateau. The time-dependant Fe dissolution datasets were best described by a model comprising three acid-extractable Fe pools each dissolving according to first-order kinetics. The dissolution rate constant k of each pool was independent of the source (Saharan or Asian) and the size (PM20, PM10 or PM2.5) of the dust but highly dependent on pH. The "fast" Fe pool had a k (25 h-1 at pH=1) of a similar magnitude to "dry" ferrihydrite nanoparticles and/or poorly crystalline Fe(III) oxyhydroxide, while the "intermediate" and "slow" Fe pools had k values respectively 50-60 times and 3000-4000 times smaller than the "fast" pool. The "slow" Fe pool was likely to consist of both crystalline Fe oxide phases (i.e., goethite and/or hematite) and Fe contained in the clay minerals. The initial mass of the "fast", "intermediate" and "slow" Fe pools represented respectively about 0.5-2%, 1-3% and 15-40% of the total Fe in the dust samples. Furthermore, we showed that in systems with low dust/liquid ratios, Fe can be dissolved from all three phases, whereas at high dust/liquid ratios (e.g., in aerosols), sufficient Fe is solubilised from the "fast" phase to dominate the Fe dissolved and to suppress the dissolution of Fe from the other Fe pools. These data demonstrated that dust/liquid ratio and pH are fundamental parameters controlling Fe dissolution kinetics in the dust. In order to reduce errors in atmospheric and climate models, these fundamental controlling factors need to be included.

Iron dissolution kinetics of mineral dust at low pH during simulated atmospheric processing

NASA Astrophysics Data System (ADS)

Shi, Z.; Bonneville, S.; Krom, M. D.; Carslaw, K. S.; Jickells, T. D.; Baker, A. R.; Benning, L. G.

2011-02-01

We investigated the iron (Fe) dissolution kinetics of African (Tibesti) and Asian (Beijing) dust samples at acidic pH with the aim of reproducing the low pH conditions in atmospheric aerosols. The Beijing dust and three size fractions of the Tibesti dust (<20 μm: PM20; <10 μm: PM10; and <2.5 μm: PM2.5) were dissolved at pH 1, 2 and/or 3 for up to 1000 h. In the first 10 min, all dust samples underwent an extremely fast Fe solubilisation. Subsequently, the Fe dissolution proceeded at a much slower rate before reaching a stable dissolution plateau. The time-dependant Fe dissolution datasets were best described by a model comprising three acid-extractable Fe pools each dissolving according to first-order kinetics. The dissolution rate constant k (h-1) of each pool was independent of the source (Saharan or Asian) and the size (PM20, PM10 or PM2.5) of the dust but highly dependent on pH. The "fast" Fe pool had a k (25 h-1 at pH = 1) of a similar magnitude to "dry" ferrihydrite nanoparticles and/or poorly crystalline Fe(III) oxyhydroxide, while the "intermediate" and "slow" Fe pools had k values respectively 50-60 times and 3000-4000 times smaller than the "fast" pool. The "slow" Fe pool was likely to consist of both crystalline Fe oxide phases (i.e., goethite and/or hematite) and Fe contained in the clay minerals. The initial mass of the "fast", "intermediate" and "slow" Fe pools represented respectively about 0.5-2%, 1-3% and 15-40% of the total Fe in the dust samples. Furthermore, we showed that in systems with low dust/liquid ratios, Fe can be dissolved from all three pools, whereas at high dust/liquid ratios (e.g., in aerosols), sufficient Fe may be solubilised from the "fast" phase to dominate the Fe dissolved and to suppress the dissolution of Fe from the other Fe pools. These data demonstrated that dust/liquid ratio and pH are fundamental parameters controlling Fe dissolution kinetics in the dust. In order to reduce errors in atmospheric and climate models, these fundamental controlling factors need to be included.

Active Dust Mitigation Technology for Thermal Radiators for Lunar Exploration

NASA Technical Reports Server (NTRS)

Calle, C. I.; Buhler, C. R.; Hogue, M. D.; Johansen, M. R.; Hopkins, J. W.; Holloway, N. M. H.; Connell, J. W.; Chen, A.; Irwin, S. A.; Case, S. O.;

Interaction force in a vertical dust chain inside a glass box.

PubMed

Kong, Jie; Qiao, Ke; Matthews, Lorin S; Hyde, Truell W

2014-07-01

Small number dust particle clusters can be used as probes for plasma diagnostics. The number of dust particles as well as cluster size and shape can be easily controlled employing a glass box placed within a Gaseous Electronics Conference (GEC) rf reference chamber to provide confinement of the dust. The plasma parameters inside this box and within the larger plasma chamber have not yet been adequately defined. Adjusting the rf power alters the plasma conditions causing structural changes of the cluster. This effect can be used to probe the relationship between the rf power and other plasma parameters. This experiment employs the sloshing and breathing modes of small cluster oscillations to examine the relationship between system rf power and the particle charge and plasma screening length inside the glass box. The experimental results provided indicate that both the screening length and dust charge decrease as rf power inside the box increases. The decrease in dust charge as power increases may indicate that ion trapping plays a significant role in the sheath.

Effects of Long-Term Dust Exposure on Human Respiratory System Health in Minqin County, China.

PubMed

Wang, Jinyu; Li, Sheng; Wang, Shigong; Shang, Kezheng

2015-01-01

The aim of this study was to assess the effects of long-term sand dust exposure on human respiratory health. Dust events break out frequently in Minqin County, northwest China, whereas Pingliang City, northwest China, is rarely influenced by dust events. Therefore, Minqin and Pingliang were selected as sand dust exposure region and control area, respectively. The incidence of respiratory system diseases and symptoms was determined through a structured respiratory health questionnaire (ATS-DLD-78-A) and personal interviews. The subjects comprised 728 farmers (Minqin, 424; Pingliang, 304) aged 40 years or older, who had nondocumented occupational history to industrial dust exposure. Prevalences (odds ratio [OR], 95% confidence interval [CI]) of chronic rhinitis, chronic bronchitis, and chronic cough increased 9.6% (3.141, 1.776-5.555), 7.5% (2.468, 1.421-4.286), and 10.2% (1.787, 1.246-2.563) in Minqin comparison with Pingliang, respectively, and the differences were significant (p <.01).

Longitudinal decline in lung function measurements among Saskatchewan grain workers.

PubMed

Pahwa, Punam; Senthilselvan, Ambikaipakan; McDuffie, Helen H; Dosman, James A

2003-04-01

To evaluate the relationship between the long term effects of grain dust and decline in lung function among grain elevator workers in Saskatchewan, studied over a 15-year period. The Grain Dust Medical Surveillance Program was started by Labour Canada in 1978 and longitudinally studied the respiratory health of Canadian grain elevator workers over a 15-year period (1978 to 1993). Data on respiratory symptoms and pulmonary function tests (forced expiratory volume in 1 s [FEV1], forced vital capacity [FVC]) were collected once every three years; each three-year interval was called a 'cycle'. Data from Saskatchewan were analyzed for this report. A transitional model using the generalized estimating equations approach was fitted using a SAS macro to predict the annual decline in FEV1 and FVC. Previous lung function, as one of the covariates in the transitional model, played an important role. Significant predictors of FEV1 were previous FEV1, base height, weight, years in the grain industry, current smoking status, cycle II, cycle III and cycle V. Significant predictors of FVC were previous FVC, base height, weight, years in the grain industry, cycle II, cycle III and cycle IV. The estimated annual decline in FEV1 and FVC increased according to length of time in the grain industry among nonsmoking, ex-smoking and smoking grain elevator workers. Lung function values improved after dust control, and yearly declines in FEV1 and FVC after dust control were smaller compared with yearly losses before dust control.

30 CFR 74.9 - Quality assurance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Quality assurance. 74.9 Section 74.9 Mineral... DUST SAMPLING DEVICES Requirements for Continuous Personal Dust Monitors § 74.9 Quality assurance. (a) General requirements. The applicant shall establish and maintain a quality control system that assures...

41 CFR 50-204.50 - Gases, vapors, fumes, dusts, and mists.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Contaminants for 1968” of the American Conference of Governmental Industrial Hygienists, except for the ANSI... this section, feasible administrative or engineering controls must first be determined and implemented... competent industrial hygienist or other technically qualified source. Table II—Mineral Dusts Substance Mppcf...

41 CFR 50-204.50 - Gases, vapors, fumes, dusts, and mists.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Contaminants for 1968” of the American Conference of Governmental Industrial Hygienists, except for the ANSI... this section, feasible administrative or engineering controls must first be determined and implemented... competent industrial hygienist or other technically qualified source. Table II—Mineral Dusts Substance Mppcf...

41 CFR 50-204.50 - Gases, vapors, fumes, dusts, and mists.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Contaminants for 1968” of the American Conference of Governmental Industrial Hygienists, except for the ANSI... this section, feasible administrative or engineering controls must first be determined and implemented... competent industrial hygienist or other technically qualified source. Table II—Mineral Dusts Substance Mppcf...

41 CFR 50-204.50 - Gases, vapors, fumes, dusts, and mists.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Contaminants for 1968” of the American Conference of Governmental Industrial Hygienists, except for the ANSI... this section, feasible administrative or engineering controls must first be determined and implemented... competent industrial hygienist or other technically qualified source. Table II—Mineral Dusts Substance Mppcf...

41 CFR 50-204.50 - Gases, vapors, fumes, dusts, and mists.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Contaminants for 1968” of the American Conference of Governmental Industrial Hygienists, except for the ANSI... this section, feasible administrative or engineering controls must first be determined and implemented... competent industrial hygienist or other technically qualified source. Table II—Mineral Dusts Substance Mppcf...

Work Tasks as Determinants of Grain Dust and Microbial Exposure in the Norwegian Grain and Compound Feed Industry.

PubMed

Straumfors, Anne; Heldal, Kari Kulvik; Wouters, Inge M; Eduard, Wijnand

2015-07-01

The grain and compound feed industry entails inevitable risks of exposure to grain dust and its microbial content. The objective of this study was therefore to investigate task-dependent exposure differences in order to create knowledge basis for awareness and exposure reducing measures in the Norwegian grain and compound feed industry. A total of 166 samples of airborne dust were collected by full-shift personal sampling during work in 20 grain elevators and compound feed mills during one autumn season and two winter seasons. The personal exposure to grain dust, endotoxins, β-1→3-glucans, bacteria, and fungal spores was quantified and used as individual outcomes in mixed models with worker nested in company as random effect and different departments and tasks as fixed effects. The exposure levels were highest in grain elevator departments. Exposure to endotoxins was particularly high. Tasks that represented the highest and lowest exposures varied depending on the bioaerosol component. The most important determinants for elevated dust exposure were cleaning and process controlling. Cleaning increased the dust exposure level by a factor of 2.44 of the reference, from 0.65 to 1.58mg m(-3), whereas process controlling increased the dust exposure level by a factor of 2.97, from 0.65 to 1.93mg m(-3). Process controlling was associated with significantly less grain dust exposure in compound feed mills and the combined grain elevators and compound feed mills, than in grain elevators. The exposure was reduced by a factor of 0.18 and 0.22, from 1.93 to 0.34mg m(-3) and to 0.42mg m(-3), respectively, compared with the grain elevators. Inspection/maintenance, cleaning, and grain rotation and emptying were determinants of higher exposure to both endotoxin and β-1→3-glucans. Seed winnowing was in addition a strong determinant for endotoxin, whereas mixing of animal feed implied higher β-1→3-glucan exposure. Cleaning was the only task that contributed significantly to higher exposure to bacteria and fungal spores. Cleaning in all companies and process controlling in grain elevators were the strongest determinants for overall exposure, whereas seed winnowing was a particular strong determinant of endotoxin exposure. Exposure reduction by technical intervention or personal protective equipment should therefore be considered at work places with identified high exposure tasks. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Using an Instrumented Drone to Sample Dust Devils

NASA Astrophysics Data System (ADS)

Jackson, Brian; Lorenz, Ralph; Davis, Karan; Lipple, Brock

2017-10-01

Dust devils are low-pressure, small (many to tens of meters) convective vortices powered by surface heating and rendered visible by lofted dust. Dust devils occur in arid climates on Earth, where they degrade air quality and pose a hazard to small aircraft. They also occur ubiquitously on Mars, where they may dominate the supply of atmospheric dust. Since dust contributes significantly to Mars’ atmospheric heat budget, dust devils probably play an important role in its climate. The dust-lifting capacity of a devil likely depends sensitively on its structure, particularly the wind and pressure profiles, but the exact dependencies are poorly constrained. Thus, the exact contribution to Mars’ atmosphere remains unresolved. Moreover, most previous studies of martian dust devils have relied on passive sampling of the profiles via meteorology packages on landed spacecraft, resulting in random encounter geometries which non-trivially skew the retrieved profiles. Analog studies of terrestrial devils have employed more active sampling (instrumented vehicles or manned aircraft) but have been limited to near-surface (few meters) or relatively high altitude (hundreds of meters) sampling. Unmanned aerial vehicles (UAVs) or drones, combined with miniature, digital instrumentation, promise a novel and uniquely powerful platform from which to sample dust devils via (relatively) controlled geometries at a wide variety of altitudes. In this presentation, we will describe a pilot study using an instrumented quadcopter on an active field site in southeastern Oregon, which (to our knowledge) has not previously been surveyed for dust devils. We will present preliminary results from the resulting encounters, including stereo image analysis and encounter footage collected onboard the drone.

The evaluation and quantification of respirable coal and silica dust concentrations: a task-based approach.

PubMed

Grové, T; Van Dyk, T; Franken, A; Du Plessis, J

2014-01-01

Silicosis and coal worker's pneumoconiosis are serious occupational respiratory diseases associated with the coal mining industry and the inhalation of respirable dusts containing crystalline silica. The purpose of this study (funded by the Mine Health and Safety Council of South Africa) was to evaluate the individual contributions of underground coal mining tasks to the respirable dust and respirable silica dust concentrations in an underground section by sampling the respirable dust concentrations at the intake and return of each task. The identified tasks were continuous miner (CM) cutting, construction, transfer of coal, tipping, and roof bolting. The respirable dust-generating hierarchy of the tasks from highest to lowest was: transfer of coal > CM right cutting > CM left cutting > CM face cutting > construction > roof bolting > tipping; and for respirable silica dust: CM left cutting > construction > transfer of coal > CM right cutting. Personal exposure levels were determined by sampling the exposures of workers performing tasks in the section. Respirable dust concentrations and low concentrations of respirable silica dust were found at the intake air side of the section, indicating that air entering the section is already contaminated. The hierarchy for personal respirable dust exposures was as follows, from highest to lowest: CM operator > cable handler > miner > roof bolt operator > shuttle car operator, and for respirable silica dust: shuttle car operator > CM operator > cable handler > roof bolt operator > miner. Dust control methods to lower exposures should include revision of the position of workers with regard to the task performed, positioning of the tasks with regard to the CM cutting, and proper use of the line curtains to direct ventilation appropriately. The correct use of respiratory protection should also be encouraged.

Laboratory Studies of Optical Characteristics and Condensation Processes of Cosmic Dust Particles

NASA Technical Reports Server (NTRS)

Spann, J. F., Jr.; Abbas, M. M.; Venturini, C. C.

2000-01-01

Information about the optical characteristics and physical processes involving cosmic dust particles is vital for interpretation of astronomical observations and an understanding of the formation and processing of dust in the evolutionary cycle of matter in the interstellar medium. Cosmic dust particles are formed in a variety of astrophysical environments such as in cool stellar outflows and circumstellar envelopes. Definitive knowledge of the nature, composition, and physical processes of cosmic dust grains, however, can only be inferred from astronomical observations through laboratory experiments on the analogs of hypothesized dust particles and with modeling calculations. Laboratory investigations of the nature, composition, and optical characteristics of cosmic dust particles are being, carried out at many institutions with a variety of experimental techniques. Despite a wealth of available data, however, many basic issues remain unresolved. An experimental facility based on suspension of dust particles in electrodynamic balance in a pressure/temperature controlled environment in a cavity has been operational at the NASA Marshall Space Flight Center, and is currently being employed for studies of dust particle charging mechanisms using electron beams and with UV radiation. In this paper, we discuss two general classes of experiments under planning stages that may be simultaneously carried out on this facility for cosmic dust investigations (i) Infrared optical characteristics (extinction coefficients and scattering phase functions) of the analogs of hypothesized of cosmic dust particles, such as natural and synthetic amorphous silicates with varying compositions, amorphous carbon grains, polycyclic aromatic hydrocarbons (PAHs), and icy core-mantle particles etc. The initial spectral range under consideration is 1-25 micrometers, to be extended to the far infrared region in the future (ii) Condensation of volatile gases on nucleus dust particles to be investigated for planetary and astrophysical environments.

Some Dust/Ocean Connections - Past, Present, and Future

NASA Astrophysics Data System (ADS)

Duce, R. A.

2015-12-01

Atmospheric dust has been the subject of communications for more than 3000 years, since the ancient Chinese book Chronicles Reported on Bamboo Shoots in 1150 BC. Similar reports of hwangsa and woo-tou in ancient Korean and kosa in ancient Japanese literature also indicated major Asian dust events in those areas. Western observers noted dust storms in India and Afghanistan in the early 1800s, while in the 1840s Darwin surmised that Sahara dust could be an important component of marine sedimentation in the North Atlantic. More recent interest has focused on the importance of dust as a source of the nutrients iron and phosphorus in the global ocean and the role of iron as a limiting nutrient in many areas of the surface ocean. While significant progress has been made in the past 25 years in identifying important dust/ocean connections, many issues remain. Included are the relative dearth of long-term measurements of atmospheric dust (and iron and phosphorus) over and deposition to the ocean, especially in the southern hemisphere; comparisons between modeled and measured deposition of dust to the ocean; and the solubility of iron and phosphorus (and thus their availability as nutrients) after the mineral matter enters the ocean. Addressing these problems will certainly help to provide more accurate estimates of the input of dust to the ocean and its impacts. However, future changes in dust emissions in a warmer world as well as changes in the acid/base environment that mineral dust experiences during its transport and deposition as a result of emission controls on atmospheric NOx and SO2 are two facors that may change the input of these nutrients to the ocean and their impacts in the coming years. These and other issues will be reviewed in this paper.

Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region

NASA Astrophysics Data System (ADS)

Iwata, Ayumi; Matsuki, Atsushi

2018-02-01

In order to better characterize ice nucleating (IN) aerosol particles in the atmosphere, we investigated the chemical composition, mixing state, and morphology of atmospheric aerosols that nucleate ice under conditions relevant for mixed-phase clouds. Five standard mineral dust samples (quartz, K-feldspar, Na-feldspar, Arizona test dust, and Asian dust source particles) were compared with actual aerosol particles collected from the west coast of Japan (the city of Kanazawa) during Asian dust events in February and April 2016. Following droplet activation by particles deposited on a hydrophobic Si (silicon) wafer substrate under supersaturated air, individual IN particles were located using an optical microscope by gradually cooling the temperature to -30 °C. For the aerosol samples, both the IN active particles and non-active particles were analyzed individually by atomic force microscopy (AFM), micro-Raman spectroscopy, and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Heterogeneous ice nucleation in all standard mineral dust samples tested in this study was observed at consistently higher temperatures (e.g., -22.2 to -24.2 °C with K-feldspar) than the homogeneous freezing temperature (-36.5 °C). Meanwhile, most of the IN active atmospheric particles formed ice below -28 °C, i.e., at lower temperatures than the standard mineral dust samples of pure components. The most abundant IN active particles above -30 °C were predominantly irregular solid particles that showed clay mineral characteristics (or mixtures of several mineral components). Other than clay, Ca-rich particles internally mixed with other components, such as sulfate, were also regarded as IN active particle types. Moreover, sea salt particles were predominantly found in the non-active fraction, and internal mixing with sea salt clearly acted as a significant inhibiting agent for the ice nucleation activity of mineral dust particles. Also, relatively pure or fresh calcite, Ca(NO3)2, and (NH4)2SO4 particles were more often found in the non-active fraction. In this study, we demonstrated the capability of the combined single droplet freezing method and thorough individual particle analysis to characterize the ice nucleation activity of atmospheric aerosols. We also found that dramatic changes in the particle mixing states during long-range transport had a complex effect on the ice nucleation activity of the host aerosol particles. A case study in the Asian dust outflow region highlighted the need to consider particle mixing states, which can dramatically influence ice nucleation activity.

The Impact of Meteoroid Streams on the Lunar Atmosphere and Dust Environment During the LADEE Mission

NASA Technical Reports Server (NTRS)

Stubbs, T. J.; Glenar, D. A.; Wang, Y.; Hermalyn, B.; Sarantos, M.; Colaprete, A.; Elphic, R. C.

2015-01-01

The scientific objectives of the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission are: (1) determine the composition of the lunar atmosphere, investigate processes controlling distribution and variability - sources, sinks, and surface interactions; and (2) characterize the lunar exospheric dust environment, measure spatial and temporal variability, and influences on the lunar atmosphere. Impacts on the lunar surface from meteoroid streams encountered by the Earth-Moon system are anticipated to result in enhancements in the both the lunar atmosphere and dust environment. Here we describe the annual meteoroid streams expected to be incident at the Moon during the LADEE mission, and their anticipated effects on the lunar environment.

Large Bright Ripples

NASA Technical Reports Server (NTRS)

2004-01-01

3 February 2004 Wind is the chief agent of change on Mars today. Wind blows dust and it can move coarser sediment such as sand and silt. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows bright ripples or small dunes on the floors of troughs northeast of Isidis Planitia near 31.1oN, 244.6oW. The picture covers an area 3 km (1.9 mi) wide; sunlight illuminates the scene from the lower left.

Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Siyu; Zhao, Chun; Qian, Yun

The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust massmore » balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.« less

Workplace exposures and oesophageal cancer

PubMed Central

Parent, M.; Siemiatycki, J.; Fritschi, L.

2000-01-01

OBJECTIVES—To describe the relation between oesophageal cancer and many occupational circumstances with data from a population based case-control study.
METHODS—Cases were 99 histologically confirmed incident cases of cancer of the oesophagus, 63 of which were squamous cell carcinomas. Various control groups were available; for the present analysis a group was used that comprised 533 population controls and 533 patients with other types of cancer. Detailed job histories were elicited from all subjects and were translated by a team of chemists and hygienists for evidence of exposure to 294 occupational agents. Based on preliminary results and a review of literature, a set of 35 occupational agents and 19 occupations and industry titles were selected for this analysis. Logistic regression analyses were adjusted for age, birthplace, education, respondent (self or proxy), smoking, alcohol, and β-carotene intake.
RESULTS—Sulphuric acid and carbon black showed the strongest evidence of an association with oesophageal cancer, particularly squamous cell carcinoma. Other substances showed excess risks, but the evidence was more equivocal—namely chrysotile asbestos, alumina, mineral spirits, toluene, synthetic adhesives, other paints and varnishes, iron compounds, and mild steel dust. There was considerable overlap in occupational exposure patterns and results for some of these substances may be mutually confounded. None of the occupations or industry titles showed a clear excess risk; the strongest hints were for warehouse workers, food services workers, and workers from the miscellaneous food industry.
CONCLUSIONS—The data provide some support for an association between oesophageal cancer and a handful of occupational exposures, particularly sulphuric acid and carbon black. Many of the associations found have never been examined before and warrant further investigation.


Keywords: oesophageal cancer; occupational exposures; occupations PMID:10769298

Dust Aerosol, Clouds, and the Atmospheric Optical Depth Record over 5 Mars Years of the Mars Exploration Rover Mission

NASA Technical Reports Server (NTRS)

Lemmon, Mark T.; Wolff, Michael J.; Bell, James F., III; Smith, Michael D.; Cantor, Bruce A.; Smith, Peter H.

2014-01-01

Dust aerosol plays a fundamental role in the behavior and evolution of the Martian atmosphere. The first five Mars years of Mars Exploration Rover data provide an unprecedented record of the dust load at two sites. This record is useful for characterization of the atmosphere at the sites and as ground truth for orbital observations. Atmospheric extinction optical depths have been derived from solar images after calibration and correction for time-varying dust that has accumulated on the camera windows. The record includes local, regional, and globally extensive dust storms. Comparison with contemporaneous thermal infrared data suggests significant variation in the size of the dust aerosols, with a 1 micrometer effective radius during northern summer and a 2 micrometer effective radius at the onset of a dust lifting event. The solar longitude (L (sub s)) 20-136 degrees period is also characterized by the presence of cirriform clouds at the Opportunity site, especially near LS = 50 and 115 degrees. In addition to water ice clouds, a water ice haze may also be present, and carbon dioxide clouds may be present early in the season. Variations in dust opacity are important to the energy balance of each site, and work with seasonal variations in insolation to control dust devil frequency at the Spirit site.

Two Key Parameters Controlling Particle Clumping Caused by Streaming Instability in the Dead-zone Dust Layer of a Protoplanetary Disk

NASA Astrophysics Data System (ADS)

Sekiya, Minoru; Onishi, Isamu K.

2018-06-01

The streaming instability and Kelvin–Helmholtz instability are considered the two major sources causing clumping of dust particles and turbulence in the dust layer of a protoplanetary disk as long as we consider the dead zone where the magnetorotational instability does not grow. Extensive numerical simulations have been carried out in order to elucidate the condition for the development of particle clumping caused by the streaming instability. In this paper, a set of two parameters suitable for classifying the numerical results is proposed. One is the Stokes number that has been employed in previous works and the other is the dust particle column density that is nondimensionalized using the gas density in the midplane, Keplerian angular velocity, and difference between the Keplerian and gaseous orbital velocities. The magnitude of dust clumping is a measure of the behavior of the dust layer. Using three-dimensional numerical simulations of dust particles and gas based on Athena code v. 4.2, it is confirmed that the magnitude of dust clumping for two disk models are similar if the corresponding sets of values of the two parameters are identical to each other, even if the values of the metallicity (i.e., the ratio of the columns density of the dust particles to that of the gas) are different.

A 16-year record of eolian dust in Southern Nevada and California, USA: Controls on dust generation and accumulation

USGS Publications Warehouse

Reheis, M.C.

2006-01-01

An ongoing project monitors modern dust accumulation in the arid southwestern United States to (1) determine the rate and composition of dust inputs to soils and (2) relate dust accumulation to weather patterns to help predict the effects of climate change on dust production and accumulation. The 16-year records of 35 dust-trap sites in the eastern Mojave Desert and southern Great Basin reveal how generation and accumulation of dust, including the silt-clay, carbonate, and soluble-salt fractions, is affected by the amount and seasonal distribution of rainfall and the behavior of different source types (alluvium, dry playas, and wet playas). Accumulation rates (fluxes) of the silt-clay fraction of dust, including carbonates, range from about 2-20 g/m2/yr. Average rates are higher in the southern part of the study area (south of latitude 36.5??N) and annually fluctuate over a larger range than rates in the northern part of the area. Sites throughout the study area show peaks in dust flux in the 1984-1985 sampling period and again in 1997-1999; northern sites also show increased flux in 1987-1988 and southern sites in 1989-1991. These peaks of dust flux correspond with both La Nina (dry) conditions and with strong El Nino (wet) periods. The accumulation rates of different components of mineral dusts fluctuate differently. For example, soluble-salt flux increases in 1987-1988, coincident with a moderate El Nino event, and increases very strongly in 1997-1999, overlapping with a strong El Nino event. Both of these high-rainfall winters were preceded and accompanied by strong summer rains. In contrast, little or no change in soluble-salt flux occurred during other periods of high winter rainfall but little summer rain, e.g. 1992-1995. The differences between northern vs. southern sites and between sites with playa dust sources vs. alluvial dust sources indicate that regional differences in the response of precipitation and vegetation growth to ENSO influence and differences in the response of source types control dust production and accumulation. A major factor is the hydrologic condition of surface sediments. The silt-clay and soluble-salt fluxes increased during the El Nino events of 1987-1988 and 1997-1998 at sites close to "wet" playas with shallow depths to groundwater (<10 m), consistent with the concept that active evaporative concentration of salts disrupts surface crusts and increases the susceptibility of surface sediment to deflation. The silt-clay flux also increased during drought periods (1989-1991, 1995-1997) at sites downwind of alluvial sources and "dry" playas with deeper groundwater (<10 m). These increases are probably related to the die-off of drought-stressed vegetation on alluvial sediments, and in some cases to local runoff events that deliver fresh sediment to playa margins and distal portions of alluvial fans. ?? 2006 Elsevier Ltd. All rights reserved.

Optical Extinction Measurements of Dust Density in the GMRO Regolith Test Bin

NASA Technical Reports Server (NTRS)

Lane, J.; Mantovani, J.; Mueller, R.; Nugent, M.; Nick, A.; Schuler, J.; Townsend, I.

2016-01-01

A regolith simulant test bin was constructed and completed in the Granular Mechanics and Regolith Operations (GMRO) Lab in 2013. This Planetary Regolith Test Bed (PRTB) is a 64 sq m x 1 m deep test bin, is housed in a climate-controlled facility, and contains 120 MT of lunar-regolith simulant, called Black Point-1 or BP-1, from Black Point, AZ. One of the current uses of the test bin is to study the effects of difficult lighting and dust conditions on Telerobotic Perception Systems to better assess and refine regolith operations for asteroid, Mars and polar lunar missions. Low illumination and low angle of incidence lighting pose significant problems to computer vision and human perception. Levitated dust on Asteroids interferes with imaging and degrades depth perception. Dust Storms on Mars pose a significant problem. Due to these factors, the likely performance of telerobotics is poorly understood for future missions. Current space telerobotic systems are only operated in bright lighting and dust-free conditions. This technology development testing will identify: (1) the impact of degraded lighting and environmental dust on computer vision and operator perception, (2) potential methods and procedures for mitigating these impacts, (3) requirements for telerobotic perception systems for asteroid capture, Mars dust storms and lunar regolith ISRU missions. In order to solve some of the Telerobotic Perception system problems, a plume erosion sensor (PES) was developed in the Lunar Regolith Simulant Bin (LRSB), containing 2 MT of JSC-1a lunar simulant. PES is simply a laser and digital camera with a white target. Two modes of operation have been investigated: (1) single laser spot - the brightness of the spot is dependent on the optical extinction due to dust and is thus an indirect measure of particle number density, and (2) side-scatter - the camera images the laser from the side, showing beam entrance into the dust cloud and the boundary between dust and void. Both methods must assume a mean particle size in order to extract a number density. The optical extinction measurement yields the product of the 2nd moment of the particle size distribution and the extinction efficiency Qe. For particle sizes in the range of interest (greater than 1 micrometer), Qe approximately equal to 2. Scaling up of the PES single laser and camera system is underway in the PRTB, where an array of lasers penetrate a con-trolled dust cloud, illuminating multiple targets. Using high speed HD GoPro video cameras, the evolution of the dust cloud and particle size density can be studied in detail.

Pulmonary risk of intraoral surface conditioning using crystalline silica.

PubMed

Mayer, Beate; Raithel, Hans; Weltle, Dieter; Niedermeier, Wilhelm

2003-01-01

This study evaluated the pulmonary risk caused by possible respirable dust of Al2O3 and SiO(x) resulting from chairside tribochemical sandblasting procedures in a dental office. Dust was collected using a trap near the working field, and quantitative morphologic determination and identification were performed with SEM and EDAX. Forty blasting processes (total time 20 minutes) were aimed at a dummy to obtain maximum pollution of the workplace. Respirable dust fraction was measured using personal air samplers with an 8-microm cellulose-nitrate filter and a volume flow rate of 2 L/min. Mass of the respirable dust fraction was determined, and respirable free crystalline silica was identified with the help of infrared spectroscopy. Blasting of metal or ceramic surfaces with tribochemical agents produces respirable and potentially harmful SiO(x) and Al2O3 particles with a diameter of less than 5 microm, showing a total concentration in the air of less than 0.3 mg/m3. With and without dental suction, the concentration of the respirable free crystalline silica was smaller than 0.02 mg/m3. Concern regarding the risk of chairside tribochemical methods and possible impairment of health of patients and dental staff is unfounded, even under extreme conditions or without protective measures, since the concentrations of SiO(x) found in the air of the workplace were far below the current threshold value of 0.15 mg/m3.

Large-Scale, Extratropical Weather Systems within Mars' Atmosphere

NASA Astrophysics Data System (ADS)

Hollingsworth, Jeffery L.

2013-04-01

During late autumn through early spring, extratropical regions on Mars exhibit profound mean zonal equator-to-pole thermal contrasts. The imposition of this strong meridional temperature variation supports intense eastward-traveling, synoptic weather systems (i.e., transient baroclinic/barotropic waves) within Mars' extratropical atmosphere. Such disturbances grow, mature and decay within the east-west varying seasonal-mean midlatitude jet stream (i.e., the polar vortex) on the planet. Near the surface, the weather disturbances indicated large-scale spiraling "comma"-shaped dust cloud structures and scimitar-shaped dust fronts, indicative of processes associated with cyclo-/fronto-genesis. The weather systems occur during specific seasons on Mars, and in both hemispheres. The northern hemisphere (NH) disturbances are significantly more intense than their counterparts in the southern hemisphere (SH). Further, the NH weather systems and accompanying frontal waves appear to have significant impacts on the transport of tracer fields (e.g., particularly dust and to some extent water species (vapor/ice) as well). And regarding dust, frontal waves appear to be key agents in the lifting, lofting, organization and transport of this particular atmospheric aerosol. In this paper, a brief background and supporting observations of Mars' extratropical weather systems is presented. This is followed by a short review of the theory and various modeling studies (i.e., ranging from highly simplified, mechanistic and full global circulation modeling investigations) which have been pursued. Finally, a discussion of outstanding issues and questions regarding the character and nature of Mars' extratropical traveling weather systems is offered.

Large-Scale Extratropical Weather Systems in Mars' Atmosphere

NASA Technical Reports Server (NTRS)

Hollingsworth, Jeffery L.

2013-01-01

During late autumn through early spring, extratropical regions on Mars exhibit profound mean zonal equator-to-pole thermal contrasts. The imposition of this strong meridional temperature variation supports intense eastward-traveling, synoptic weather systems (i.e., transient baroclinic/barotropic waves) within Mars' extratropical atmosphere. Such disturbances grow, mature and decay within the east-west varying seasonal-mean midlatitude jet stream (i.e., the polar vortex) on the planet. Near the surface, the weather disturbances indicated large-scale spiraling "comma"-shaped dust cloud structures and scimitar-shaped dust fronts, indicative of processes associated with cyclo-/fronto-genesis. The weather systems occur during specific seasons on Mars, and in both hemispheres. The northern hemisphere (NH) disturbances are significantly more intense than their counterparts in the southern hemisphere (SH). Further, the NH weather systems and accompanying frontal waves appear to have significant impacts on the transport of tracer fields (e.g., particularly dust and to some extent water species (vapor/ice) as well). And regarding dust, frontal waves appear to be key agents in the lifting, lofting, organization and transport of this particular atmospheric aerosol. In this paper, a brief background and supporting observations of Mars' extratropical weather systems is presented. This is followed by a short review of the theory and various modeling studies (i.e., ranging from highly simplified, mechanistic and full global circulation modeling investigations) which have been pursued. Finally, a discussion of outstanding issues and questions regarding the character and nature of Mars' extratropical traveling weather systems is offered.

A study of long-term trends in mineral dust aerosol distributions in Asia using a general circulation model

NASA Astrophysics Data System (ADS)

Mukai, Makiko; Nakajima, Teruyuki; Takemura, Toshihiko

2004-10-01

Dust events have been observed in Japan with high frequency since 2000. On the other hand, the frequency of dust storms is said to have decreased in the desert regions of China since about the middle of the 1970s. This study simulates dust storms and transportation of mineral dust aerosols in the east Asia region from 1981 to 2001 using an aerosol transport model, Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS), implemented in the Center for Climate System Research/National Institute for Environmental Studies atmospheric global circulation model, in order to investigate the main factors that control a dust event and its long-term variation. The model was forced to simulate a real atmospheric condition by a nudging technique using European Centre for Medium-Range Weather Forecasts reanalysis data on wind velocities, temperature, specific humidity, soil wetness, and snow depth. From a comparison between the long-term change in the dust emission and model parameters, it is found that the wind speed near the surface level had a significant influence on the dust emission, and snow is also an important factor in the early spring dust emission. The simulated results suggested that dust emissions from northeast China have a great impact on dust mass concentration in downwind regions, such as the cities of northeastern China, Korea, and Japan. When the frequency of dust events was high in Japan, a low-pressure system tended to develop over the northeast China region that caused strong winds. From 2000 to 2001 the simulated dust emission flux decreased in the Taklimakan desert and the northwestern part of China, while it increased in the Gobi desert and the northeastern part of China. Consequently, dust particles seem to be transported more from the latter region by prevailing westerlies in the springtime to downwind areas as actually observed. In spite of the similarity, however, there is still a large disagreement between observed and simulated dust frequencies and concentrations. A more realistic land surface and uplift mechanism of dust particles should be modeled to improve the model simulation. Desertification of the northeastern China region may be another reason for this disagreement.

Comparison of a direct-reading device to gravimetric methods for evaluating organic dust aerosols in an enclosed swine production environment.

PubMed

Taylor, C D; Reynolds, S J

2001-01-01

The production of livestock in enclosed facilities has become an accepted practice, driven by the need for increased efficiency. Exposure to organic dusts, containing various bioactive components, has been identified an important risk factor for the high rate of lung disease found among workers in these environments. Assessment of organic dust exposure requires technical skills and instrumentation not readily available to most agricultural enterprises. Development of a simple, cost-effective method for measuring organic dust levels would be useful in evaluating and controlling exposures in these environments. The objective of this study was to evaluate the usefulness of the direct reading MIE PDM-3 Miniram for estimating organic dust concentrations in enclosed swine production facilities. Responses from the MIE PDM-3 Miniram were compared to gravimetric methods for total and inhalable dust. Total dust determinations were conducted in accordance with the National Institute for Occupational Safety and Health (NIOSH) method 0500. Inhalable particulate mass (IPM) sampling was conducted using SKC brand IOM (Institute of Occupational Medicine) sampling cassettes, which meet the American Conference of Governmental Industrial Hygienists ACGIH criteria for inhalable dust sampling. This study design also allowed for the comparison of traditional total dust method to the IPM method, in collecting organic dusts in an agricultural setting. Fifteen sets of side-by-side samples (Miniram, total dust, and IPM) were collected over a period of six months in a swine confinement building. There were statistically significant differences in the results provided by the three sampling methods. Measurements for inhalable dust exceeded those for total dust in eleven of fifteen samples. The Miniram time-weighted average (TWA) response to the organic dust was always the lower of the three methods. A high degree of correlation was found among all three methods. The Miniram performed well under field conditions of varying temperature and humidity. The Miniram has the potential to predict the inhalable and total dust concentrations, assuming a correction factor for the organic dust being measured is applied.

Lunar Dust: Characterization and Mitigation

NASA Technical Reports Server (NTRS)

Hyatt. Mark J.; Feighery, John

2007-01-01

Lunar dust is a ubiquitous phenomenon which must be explicitly addressed during upcoming human lunar exploration missions. Near term plans to revisit the moon as a stepping stone for further exploration of Mars, and beyond, places a primary emphasis on characterization and mitigation of lunar dust. Comprised of regolith particles ranging in size from tens of nanometers to microns, lunar dust is a manifestation of the complex interaction of the lunar soil with multiple mechanical, electrical, and gravitational effects. The environmental and anthropogenic factors effecting the perturbation, transport, and deposition of lunar dust must be studied in order to mitigate it's potentially harmful effects on exploration systems. The same hold true for assessing the risk it may pose for toxicological health problems if inhaled. This paper presents the current perspective and implementation of dust knowledge management and integration, and mitigation technology development activities within NASA's Exploration Technology Development Program. This work is presented within the context of the Constellation Program's Integrated Lunar Dust Management Strategy. This work further outlines the scientific basis for lunar dust behavior, it's characteristics and potential effects, and surveys several potential strategies for its control and mitigation both for lunar surface operations and within the working volumes of a lunar outpost. The paper also presents a perspective on lessons learned from Apollo and forensics engineering studies of Apollo hardware.

Dust emission from wet and dry playas in the Mojave Desert, USA

USGS Publications Warehouse

Reynolds, R.L.; Yount, J.C.; Reheis, M.; Goldstein, H.; Chavez, P.; Fulton, R.; Whitney, J.; Fuller, C.; Forester, R.M.

2007-01-01

The interactions between playa hydrology and playa-surface sediments are important factors that control the type and amount of dust emitted from playas as a result of wind erosion. The production of evaporite minerals during evaporative loss of near-surface ground water results in both the creation and maintenance of several centimeters or more of loose sediment on and near the surfaces of wet playas. Observations that characterize the texture, mineralogic composition and hardness of playa surfaces at Franklin Lake, Soda Lake and West Cronese Lake playas in the Mojave Desert (California), along with imaging of dust emission using automated digital photography, indicate that these kinds of surface sediment are highly susceptible to dust emission. The surfaces of wet playas are dynamic - surface texture and sediment availability to wind erosion change rapidly, primarily in response to fluctuations in water-table depth, rainfall and rates of evaporation. In contrast, dry playas are characterized by ground water at depth. Consequently, dry playas commonly have hard surfaces that produce little or no dust if undisturbed except for transient silt and clay deposited on surfaces by wind and water. Although not the dominant type of global dust, salt-rich dusts from wet playas may be important with respect to radiative properties of dust plumes, atmospheric chemistry, windborne nutrients and human health.

The biology of talc.

PubMed Central

Hildick-Smith, G Y

1976-01-01

Data are presented on the effects on health of talc dusts from exposure in industry and use of talc-containing health products. The mineralogy of talc and the composition of cosmetic and industrial grade talc dusts are described. Studies in animals are reviewed, and epidemiological data are considered in relation to exposures that occur during industrial and consumer uses of talc dusts. Hamsters exposed to 8 mg/m3 of respirable cosmetic grade talc dust for up to 150 minutes a day for 300 consecutive days showed no difference in incidence or nature of pathological lesions from those observed in a group of untreated animals. A retrospective study of the causes of death of 227 talc mine millers exposed to cosmetic grade talc at the threshold limit value for talc (20 million parts per cubic foot) for an average of 15-8 years showed that the causes of death were no different from those in a control cohort not exposed to talc dust. The available data indicate that talc dust exposure in the modern mining of cosmetic grade talc does not appear to be injurious to health. The significantly lower dust exposure in the normal use of cosmetic grade talc dusts in talc-containing health and cosmetic products confirms that their use is not a hazard to health. PMID:793610

Mineral phases and metals in baghouse dust from secondary aluminum production

EPA Science Inventory

Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78...

ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS, AIRFLOW PRODUCTS AFP30

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the AFP30 air filter for dust and bioaerosol filtration manufactured by Airflow Products. The pressure drop across the filter was 62 Pa clean and 247 Pa dust loaded. The filtration effici...

TSCA Section 21 Petition Requesting EPA to Lower Lead Dust Hazard Standards and Modify the Definition of Lead-based Paint in its Regulations

EPA Pesticide Factsheets

This petition requests EPA to lower lead dust hazard standards and modify the definition of lead-based paint in its regulations promulgated under sections 401 and 403 of the Toxic Substances Control Act (TSCA).

Activation of human peroxisome-activated receptor-gamma ...

EPA Pesticide Factsheets

Obesity in children has become an epidemic and recent research suggests a possible contribution from exposure to environmental chemicals. Several chemicals, such as phthalates, brominated flame retardants, and perfluorinated chemicals, are common in house dust on floors where children play and are suspected obesogens. Obesogens can act via a mechanism that involves activation of peroxisome proliferator-activated receptor-gamma (PPARy). A previous study found that dust collected from children’s homes binds to PPARy. Here, we investigated the ability of house dust to activate PPARy in a transiently transfected cell assay. Dust samples were collected in 2012 from carpeted and hardwood floors in children’s homes using thimbles fitted into a vacuum cleaner hose (“TEO” samples), or from homes in an adult cohort NIEHS study. Dust was extracted with 50:50 hexane:acetone, sonicated, centrifuged, and the organic layer collected. This was repeated 2X. The extracts were filtered to remove particulates, dried with purified nitrogen, and reconstituted in DMS0 at 200 ug/ul. COS-1 cells were transfected for 24 hrs with a human PPARy vector containing a luciferase reporter, and exposed for 24 hrs to negative controls water or DMSO (0.1%), positive controls Troglitazone (3 uM in water) or Rosiglitazone (100 nM in DMSO), or dust extracts serially diluted in DMEM at 50, 100, and 200 ug/ml in 0.1% DMSO. Cells were lysed and luciferase activity was measured. Data were log-tra

Dust influx into the northern Indian Ocean over the last 1.5 Myr.

NASA Astrophysics Data System (ADS)

Kunkelová, Tereza; Kroon, Dick; Jung, Simon; de Leau, Erica S.; Odling, Nicholas; Spezzaferri, Silvia; Hayman, Stephanie; Alonso-Garcia, Montserrat; Wright, James D.; Alvarez Zarikian, Carlos; Betzler, Christian; Eberli, Gregor P.; Jovane, Luigi; Laya, Juan Carlos; Hui-Mee, Anna Ling; Reijmer, John; Reolid, Jesus; Sloss, Craig R.

2017-04-01

Over the last 2 Ma the Earth's climate has been profoundly affected by quasi-periodic changes in the Earth's orbit around the Sun. The Earth's climate reflects cooling and warming associated with this orbital forcing, such as periods of glaciation and warmer interglacials, variations in sea surface temperatures and changes in global wind patterns. During glacial periods, dust input into the oceans increased as a result of stronger surface winds and greater source area from increased desertification. At low latitudes, the seasonality of monsoonal wind direction controls dust transport into the ocean. This research identifies the main controls on dust influx into the northern Indian Ocean over the last 1.5 Ma by analyzing the first high resolution marine sediment record from the Maldives carbonate platform (IODP Expedition 359; Site U1467), an area strongly affected by the monsoon seasons. Here we present variations in the concentration of specific normalized elements, from X-ray fluorescence spectrometry, reflecting the chemistry of the dust particles and source areas. The new dust record will be compared to other records of climate change, mainly from the North Atlantic, to investigate the degree of coupling between driving forces in the Earth's climate in the northern hemisphere. The results of this study will aid our understanding of the monsoon system, low latitude desertification, and the degree of climate coupling, essential for predicting the response of the system to future anthropogenic climate change.

POLARIZATION MEASUREMENTS OF HOT DUST STARS AND THE LOCAL INTERSTELLAR MEDIUM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, J. P.; Cotton, D. V.; Bott, K.

2016-07-10

Debris discs are typically revealed through the presence of excess emission at infrared wavelengths. Most discs exhibit excess at mid- and far-infrared wavelengths, analogous to the solar system’s Asteroid and Edgeworth-Kuiper belts. Recently, stars with strong (∼1%) excess at near-infrared wavelengths were identified through interferometric measurements. Using the HIgh Precision Polarimetric Instrument, we examined a sub-sample of these hot dust stars (and appropriate controls) at parts-per-million sensitivity in SDSS g ′ (green) and r ′ (red) filters for evidence of scattered light. No detection of strongly polarized emission from the hot dust stars is seen. We, therefore, rule out scatteredmore » light from a normal debris disk as the origin of this emission. A wavelength-dependent contribution from multiple dust components for hot dust stars is inferred from the dispersion (the difference in polarization angle in red and green) of southern stars. Contributions of 17 ppm (green) and 30 ppm (red) are calculated, with strict 3- σ upper limits of 76 and 68 ppm, respectively. This suggests weak hot dust excesses consistent with thermal emission, although we cannot rule out contrived scenarios, e.g., dust in a spherical shell or face-on discs. We also report on the nature of the local interstellar medium (ISM), obtained as a byproduct of the control measurements. Highlights include the first measurements of the polarimetric color of the local ISM and the discovery of a southern sky region with a polarization per distance thrice the previous maximum. The data suggest that λ {sub max}, the wavelength of maximum polarization, is bluer than typical.« less

The Effect of Wood Aerosols and Bioaerosols on the Respiratory Systems of Wood Manufacturing Industry Workers in Golestan Province

PubMed Central

Badirdast, Phateme; Salehpour, Soussan; Ghadjari, Ali; Khodakarim, Soheila; Panahi, Davod; Fadaei, Moslem; Rahimi, Abolfazl

2017-01-01

Background: Occupational exposure to dust leads to acute and chronic respiratory diseases, occupational asthma, and depressed lung function. In the light of a lack of comprehensive studies on the exposure of Iranian workers to wood dusts, the objective of this study was to monitor the occupational exposure to wood dust and bioaerosol, and their correlation with the lung function parameters in chipboard manufacturing industry workers. Materials and Methods: A cross-sectional study was conducted on chipboard workers in Golestan Province; a total of 150 men (100 exposed cases and 50 controls) were assessed. Workers were monitored for inhalable wood dust and lung function parameters, i.e., FVC, FEV1, FEV1/FVC, and FEF25–75%. The workers’ exposure to bioaerosols was measured using a bacterial sampler; a total of 68 area samples were collected. The analysis was performed using the Mann-Whitney, Kruskal-Wallis, and regression statistical tests. Results: The geometric mean value and geometric standard deviation of inhalable wood dust for the exposed and control groups were 19 ± 2.00 mg/m3 and 0.008 ± 0.001 mg/m3, respectively. A statistically significant correlation was observed between the lung parameters and cumulative exposure to inhalable wood dust, whereas a statistically significant correlation was not observed between the lung parameters and bioaerosol exposure. However, the exposure of Iranian workers to bioaerosols was higher, compared to their foreign coworkers. Conclusion: Considering the high level of exposure among workers in this study along with their lung function results, long-term exposure to wood dust may be detrimental to the workers’ health and steps to limit their exposure should be considered seriously. PMID:28638425

[Evaluation of the fibrogenic effect of coke dust on the lungs and internal organs of experimental animals].

PubMed

Zyłka-Włoszczyk, M; Ociepiński, M; Szaflarska-Stojko, E

1991-01-01

Based on the data collected by the Provincial Regional Administration Unit for Control of Epidemics and Hygiene in Katowice, dust concentration at the MAKOSZOWY Coking Plant in Zabrze at 18 work-places exceeded the TLV's. The purpose of this study was to determine changes within the respiratory systems of experimental animals exposed to intratracheal administration of MAKOSZOWY Coking Plant dust, sampled at the charging larry 3-4 operating stand and at the battery roof. After pulverization the dusts contained 98.1% and 99.6% respirable particles, and 6.5% and 6.0% of SiO2, respectively, determined with the Polezhajev method. They also contained aluminum and iron compounds. Hydroxyproline content in the lungs of the animals following the intratracheal administration of 50 mg of the dusts investigated 3-6 months after the experiment was determined. Determination of Hypro contend within the animals' lungs was pursued with the Stegemann method as modified by Hurych and Chvapil. The biochemical investigation results obtained were statistically analyzed with the t-Student's Test. Single intratracheal administration of dust from the battery roof work stand of the MAKOSZOWY Coking Plant caused within 6 months a statistically significant increase in the lung Hydroxyproline level in experimental animals (t = 13.10). An almost triole Hypro increase with respect to the control group was observed. No analogy between lung Hypro level increase (12.833 mg) and histological change was noted. Such a significant lung Hydroxyproline level increase could have been due to the SiO2 content of dust (6%), as well as to the presence of iron compounds in it (4.98%).(ABSTRACT TRUNCATED AT 250 WORDS)

Should precipitation influence dust emission in global dust models?

NASA Astrophysics Data System (ADS)

Okin, Gregory

2016-04-01

Soil moisture modulates the threshold shear stress required to initiate aeolian transport and dust emission. Most of the theoretical and laboratory work that has confirmed the impact of soil moisture has appropriately acknowledged that it is the soil moisture of a surface layer a few grain diameters thick that truly controls threshold shear velocity. Global and regional models of dust emission include the effect of soil moisture on transport threshold, but most ignore the fact that only the moisture of the very topmost "active layer" matters. The soil moisture in the active layer can differ greatly from that integrated through the top 2, 5, 10, or 100 cm (surface layers used by various global models) because the top 2 mm of heavy texture soils dries within ~1/2 day while sandy soils dry within less than 2 hours. Thus, in drylands where dust emission occurs, it is likely that this top layer is drier than the underlying soil in the days and weeks after rain. This paper explores, globally, the time between rain events in relation to the time for the active layer to dry and the timing of high wind events. This analysis is carried out using the same coarse reanalyses used in global dust models and is intended to inform the soil moisture controls in these models. The results of this analysis indicate that the timing between events is, in almost all dust-producing areas, significantly longer than the drying time of the active layer, even when considering soil texture differences. Further, the analysis shows that the probability of a high wind event during the period after a rain where the surface is wet is small. Therefore, in coarse global models, there is little reason to include rain-derived soil moisture in the modeling scheme.

Interannual Variability in Global Dust Storm Initiation on Mars from a GCM with Orbit-Spin Coupling and Active Dust Lifting

NASA Astrophysics Data System (ADS)

Mischna, M.; Shirley, J. H.; Newman, C. E.

2016-12-01

To first order, the occurrence and interannual variability of global dust storms (GDS) on Mars is attributable to two factors: the annual cycle of solar insolation (which delineates a specific `dust storm season'), and the changing spatial distribution and availability of dust at the surface. Recent work has now found a remarkable correspondence between the occurrence of GDS on Mars and years in which the orbital angular momentum of Mars is increasing during the dust storm season. A previously undefined acceleration term `couples' this orbital motion to the rotational motion of the planet and atmosphere, and small but persistent atmospheric accelerations (so-called `coupling term accelerations,' or CTA) change the atmospheric circulation in such a way as to seemingly be favorable to storm development. This becomes a third factor, then, that may regulate the occurrence and variability of GDS. Our prior work with the MarsWRF general circulation model (GCM) was performed either with no atmospheric dust, or with simplified, prescribed dust distributions, and illustrated the dual roles of both insolation and CTA on GDS variability. Recent advances in the MarsWRF GCM dust prescription can now tackle the remaining unaddressed factor: the role of dust availability in controlling the initiation of GDS. Simulations with both infinite and finite global sources of dust have been performed. For a prescribed dust lifting threshold, surface dust is removed from the surface, preferentially from locations with larger surface stress values, transported in the atmosphere and deposited at a later time. Compared to simulations without CTA, those with CTA show more realism in the variability of timing and magnitude of atmospheric dustiness during the dust storm season. For infinite surface dust, the primary dust lifting (peak wind stress) regions are spatially restricted, and year-to-year changes are largely due to variations in the CTA at these few locations. By contrast, in simulations with finite surface dust, the peak stress regions are rapidly exhausted, leading to a far greater distribution of primary dust lifting regions; hence, variations in the CTA over a wider area contribute to the interannual variability of GDS. Results from our suite of simulations will be shown, vis-à-vis the historical record of GDS on Mars.

[Measurement of chemical agents in metallurgy field: electric steel plant].

PubMed

Cottica, D; Grignani, E; Ghitti, R; Festa, D; Apostoli, P

2012-01-01

The steel industry maintains its important position in the context of the Italian production involving thousands of workers. The iron and steel processes are divided into primary steel industry, production of intermediate minerals, and secondary steel, scrap from the production of semi-finished industrial and consumer sector (metal inserted into components and metal used for dissipative uses, primarily coatings) and industrial waste. The paper presents the results of environmental monitoring carried out in some electric steel plant for the measurement of airborne chemicals that characterize the occupational exposure of workers employed in particular area like electric oven, to treatment outside the furnace, continuous casting area. For the sampling of the pollutants were used both personal and in fixed positions samplers. The pollutants measured are those typical of steel processes inhalable dust, metals, respirable dust, crystalline silica, but also Polycyclic Aromatic Hydrocarbons (PAH), polychlorinated dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs).

Lung cancer in relation to exposure to silica dust, silicosis and uranium production in South African gold miners

PubMed Central

Hnizdo, E.; Murray, J.; Klempman, S.

1997-01-01

BACKGROUND: A nested case-control study for lung cancer was performed on a cohort of 2260 South African gold miners in whom an association between exposure to silica dust and risk of lung cancer was previously reported. The objective was to investigate an expanded set of risk factors and also cancer cell type. METHODS: The 78 cases of lung cancer found during the follow up period from 1970 to 1986 were matched with 386 controls. Risk of lung cancer was related to smoking, exposure to silica dust, incidence of silicosis, and uranium production and the uranium content of the mine ore. RESULTS: The risk of lung cancer was associated with tobacco smoking, cumulative dust exposure, duration of underground mining, and with silicosis. The best predictive model included pack years of cigarette consumption (adjusted relative risk (RR) = 1.0 for < 6.5 pack years, 3.5 (95% confidence interval (CI) 0.7 to 16.8) for 6.5-20 pack years, 5.7 (95% CI 1.3 to 25.8) for 21-30 pack years, and 13.2 (95% CI 3.1 to 56.2) for more than 30 pack years) and silicosis (RR = 2.45 (95% CI 1.2 to 5.2)). No association was found with uranium production. The lung tumour cell type distribution was 40.3% small cell carcinoma, 38.8% squamous cell, 16.4% adenocarcinoma, and 4.5% large cell carcinoma. Small and large cell cancer combined were associated with exposure to dust. CONCLUSIONS: The results cannot be interpreted definitively in terms of causal association. Possible interpretations are: (1) subjects with high dust exposure who develop silicosis are at increased risk of lung cancer; (2) high levels of exposure to silica dust on its own is important in the pathogenesis of lung cancer and silicosis is coincidental; and (3) high levels of silica dust exposure may be a surrogate for the exposure to radon daughters. 


 PMID:9093345

Development of active porous medium filters based on plasma textiles

NASA Astrophysics Data System (ADS)

Kuznetsov, Ivan A.; Saveliev, Alexei V.; Rasipuram, Srinivasan; Kuznetsov, Andrey V.; Brown, Alan; Jasper, Warren

2012-05-01

Inexpensive, flexible, washable, and durable materials that serve as antimicrobial filters and self-decontaminating fabrics are needed to provide active protection to people in areas regularly exposed to various biohazards, such as hospitals and bio research labs working with pathogens. Airlines and cruise lines need such material to combat the spread of infections. In households these materials can be used in HVAC filters to fight indoor pollution, which is especially dangerous to people suffering from asthma. Efficient filtering materials are also required in areas contaminated by other types of hazardous dust particulates, such as nuclear dust. The primary idea that guided the undertaken study is that a microplasma-generating structure can be embedded in a textile fabric to generate a plasma sheath ("plasma shield") that kills bacterial agents coming in contact with the fabric. The research resulted in the development of a plasma textile that can be used for producing new types of self-decontaminating garments, fabrics, and filter materials, capable of activating a plasma sheath that would filter, capture, and destroy any bacteriological agent deposited on its surface. This new material relies on the unique antimicrobial and catalytic properties of cold (room temperature) plasma that is benign to people and does not cause thermal damage to many polymer textiles, such as Nomex and polypropylene. The uniqueness of cold plasma as a disinfecting agent lies in the inability of bacteria to develop resistance to plasma exposure, as they can for antibiotics. Plasma textiles could thus be utilized for microbial destruction in active antimicrobial filters (for continuous decontamination and disinfection of large amounts of air) as well as in self-decontaminating surfaces and antibacterial barriers (for example, for creating local antiseptic or sterile environments around wounds and burns).

Development of active porous medium filters based on plasma textiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuznetsov, Ivan A.; Saveliev, Alexei V.; Rasipuram, Srinivasan

2012-05-15

Inexpensive, flexible, washable, and durable materials that serve as antimicrobial filters and self-decontaminating fabrics are needed to provide active protection to people in areas regularly exposed to various biohazards, such as hospitals and bio research labs working with pathogens. Airlines and cruise lines need such material to combat the spread of infections. In households these materials can be used in HVAC filters to fight indoor pollution, which is especially dangerous to people suffering from asthma. Efficient filtering materials are also required in areas contaminated by other types of hazardous dust particulates, such as nuclear dust. The primary idea that guidedmore » the undertaken study is that a microplasma-generating structure can be embedded in a textile fabric to generate a plasma sheath (''plasma shield'') that kills bacterial agents coming in contact with the fabric. The research resulted in the development of a plasma textile that can be used for producing new types of self-decontaminating garments, fabrics, and filter materials, capable of activating a plasma sheath that would filter, capture, and destroy any bacteriological agent deposited on its surface. This new material relies on the unique antimicrobial and catalytic properties of cold (room temperature) plasma that is benign to people and does not cause thermal damage to many polymer textiles, such as Nomex and polypropylene. The uniqueness of cold plasma as a disinfecting agent lies in the inability of bacteria to develop resistance to plasma exposure, as they can for antibiotics. Plasma textiles could thus be utilized for microbial destruction in active antimicrobial filters (for continuous decontamination and disinfection of large amounts of air) as well as in self-decontaminating surfaces and antibacterial barriers (for example, for creating local antiseptic or sterile environments around wounds and burns).« less

Feedback on Measured Dust Concentrations Reduces Exposure Levels Among Farmers.

PubMed

Basinas, Ioannis; Sigsgaard, Torben; Bønløkke, Jakob Hjort; Andersen, Nils Testrup; Omland, Øyvind; Kromhout, Hans; Schlünssen, Vivi

2016-08-01

The high burden of exposure to organic dust among livestock farmers warrants the establishment of effective preventive and exposure control strategies for these workers. The number of intervention studies exploring the effectiveness of exposure reduction strategies through the use of objective measurements has been limited. To examine whether dust exposure can be reduced by providing feedback to the farmers concerning measurements of the exposure to dust in their farm. The personal dust levels of farmers in 54 pig and 26 dairy cattle farms were evaluated in two measurement series performed approximately 6 months apart. Detailed information on work tasks and farm characteristics during the measurements were registered. Participating farms were randomized a priori to a control (n = 40) and an intervention group (n = 40). Shortly after the first visit, owners of intervention farms only received a letter with information on the measured dust concentrations in the farm together with some general advises on exposure reduction strategies (e.g. use of respirators during certain tasks). Relationships between measured dust concentrations and intervention status were quantified by means of linear mixed effect analysis with farm and worker id as random effects. Season, type of farming, and work tasks were treated as fixed effects. Changes in exposure over time were explored primarily at a farm level in models combined, as well as separate for pig and cattle farmers. After adjustment for fixed effects, an overall reduction of 23% in personal dust exposures was estimated as a result of the intervention (P = 0.02). Exposure reductions attributable to the intervention were similar across pig and cattle farmers, but statistically significant only for pig farmers. Intervention effects among pig farmers did not depend on the individuals' information status; but among cattle farmers a significant 48% reduction in exposure was found only among individuals that reported to have been informed. No systematic differences in changes over time considering the use of respiratory protection between the intervention and control groups were observed. The results of the present study suggest reductions between 20 and 30% in personal exposure to inhalable dust to be feasible through simple information provided to the farm owners regarding actual levels of exposure together with instructions on basic measures of prevention. The exact reasons for these effects are unclear, but likely they involve changes in behavior and working practices among intervention farmers. © The Author 2016. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Use of dust storm observations on satellite images to identify areas vulnerable to severe wind erosion

USGS Publications Warehouse

Breed, C.S.; McCauley, J.F.

1986-01-01

Blowing dust is symptomatic of severe wind erosion and deterioration of soils in areas undergoing dessication and/or devegetation. Dust plumes on satellite images can commonly be traced to sources in marginally arable semiarid areas where protective lag gravels or vegetation have been removed and soils are dry, as demonstrated for the Portales Valley, New Mexico. Images from Landsat and manned orbiters such as Skylab and the Space Shuttle are useful for illustrating the regional relations of airborne dust plumes to source areas. Geostationary satellites such as GOES are useful in tracking the time-histories of episodic dust storms. These events sometimes go unrecognized by weather observers and are the precursors of long-term land degradation trends. In areas where soil maps and meteorological data are inadequate, satellite images provide a means for identifying problem areas where measures are needed to control or mitigate wind erosion. ?? 1986 D. Reidel Publishing Company.

The Effect of Cement Dust Exposure on Haematological Parameters of Cement Factory workers in Nalagonda, Andhra Pradesh.

NASA Astrophysics Data System (ADS)

Guguloth, Mohan Rao.; Sambanaik, A.; srinivasnaik, L.; Mude, Jagadishnaik.

2012-10-01

This study was measured on haematological parameters in workers exposed to cement dust in order to test the the hypothesis and to identify a simple, readily available, cost effective screening test that could help in identifying the presence of disease, its severity, that Cement dust exposure may perturb these functions related to their workplace.Assesment of haematological parameters were performed in 100exposed workers occupationally exposed to cement dust and 50 matched unexposed controls with ages ranging from 20-35, 35-50, 50-65 years. The blood samples were taken from them and percentage of hemoglobin, Lymphocytes / monocytes count were analysed.The hemoglobin percentage of exposed workers were significantly lower(P<0.05).Lymphocytes/Monocytes counts of exposed workers was insignificant (P<0.05).These results suggest that long term occupational exposure to cement dust may perturb haemopoietic function.

Tempest in a glass tube: A helical vortex formation in a complex plasma

NASA Astrophysics Data System (ADS)

Saitou, Yoshifumi; Ishihara, Osamu; Ishihara

2014-12-01

A collective behavior of dust particles in a complex plasma with a magnetic field (up to 4 kG) is investigated. Dust particles form a dust disk which is rotating in a horizontal plane pushed by ions rotating with the E × B drift as a trigger force. The thickness of the disk is determined by controlling the experimental conditions. The disk rotates in a horizontal plane and forms a two-dimensional thin structure when the pressure pAr is relatively high. The dust particles are ejected from near the disk center and form a rotation in the vertical plane and, hence, forms a helical vortex when the disk is thick for relatively low pAr . The reason the dust disk has the different thickness is due to the neutral pressure. Under a higher (lower) neutral gas pressure, the disk becomes two (three) dimensional due to the influence of the neutral drag force.

Fine metal dust particles on the wall probes from JET-ILW

NASA Astrophysics Data System (ADS)

Fortuna-Zaleśna, E.; Grzonka, J.; Moon, Sunwoo; Rubel, M.; Petersson, P.; Widdowson, A.; Contributors, JET

2017-12-01

Collection and ex situ studies of dust generated in controlled fusion devices during plasma operation are regularly carried out after experimental campaigns. Herewith results of the dust survey performed in JET after the second phase of operation with the metal ITER-like wall (2013-2014) are presented. For the first-time-ever particles deposited on silicon plates acting as dust collectors installed in the inner and outer divertor have been examined. The emphasis is on analysing metal particles (Be and W) with the aim to determine their composition, size and surface topography. The most important is the identification of beryllium dust in the form of droplets (both splashes and spherical particles), flakes of co-deposits and small fragments of Be tiles. Tungsten and nickel rich (from Inconel) particles are also identified. Nitrogen from plasma edge cooling has been detected in all types of particles. They are categorized and the origin of various constituents is discussed.

Construction and implementation of a novel dust dropper for the PPPL Dusty Plasma Experiment

NASA Astrophysics Data System (ADS)

Tinguely, Roy; Dominguez, Arturo; Carpe, Andrew; Zwicker, Andrew

2013-10-01

The applications of dusty plasma research are far-reaching, from understanding astrophysical systems to studying plasma-wall interactions in magnetically confined plasma experiments. Unfortunately, dusty plasma environments can be difficult to control and replicate in laboratory settings. This poster details the construction, vacuum operation, and initial results of a multifaceted dust dropper, which is being implemented in the PPPL Dusty Plasma Experiment and is expected to improve the reproducibility and characterization of dust cloud formation. The cylindrical plastic shaker comprises four pairings of electromagnets and neodymium magnets, with eight stabilizing springs. The amplitude and frequency of a pulsed current determine the dust dispersal rate, while a biased metallic mesh regulates the area of dispersion and size and charge of dropped particles. Preliminary testing shows that, for 44 micron silica dust, steady dispersal rates as fast as 0.2 mg/s (approximately 1700 particles/s) can be achieved.

Physicochemical Characteristics of Dust Particles in HVOF Spraying and Occupational Hazards: Case Study in a Chinese Company

NASA Astrophysics Data System (ADS)

Huang, Haihong; Li, Haijun; Li, Xinyu

2016-06-01

Dust particles generated in thermal spray process can cause serious health problems to the workers. Dust particles generated in high velocity oxy-fuel (HVOF) spraying WC-Co coatings were characterized in terms of mass concentrations, particle size distribution, micro morphologies, and composition. Results show that the highest instantaneous exposure concentration of dust particles in the investigated thermal spray workshop is 140 mg/m3 and the time-weighted average concentration is 34.2 mg/m3, which are approximately 8 and 4 times higher than the occupational exposure limits in China, respectively. The large dust particles above 10 μm in size present a unique morphology of polygonal or irregular block of crushed powder, and smaller dust particles mainly exist in the form of irregular or flocculent agglomerates. Some heavy metals, such as chromium, cobalt, and nickel, are also found in the air of the workshop and their concentrations are higher than the limits. Potential occupational hazards of the dust particles in the thermal spray process are further analyzed based on their characteristics and the workers' exposure to the nanoparticles is assessed using a control banding tool.

Mite fauna and fungal flora in house dust from homes of asthmatic children.

PubMed

Ishii, A; Takaoka, M; Ichinoe, M; Kabasawa, Y; Ouchi, T

1979-12-01

Mite fauna and fungal flora in the house dust from homes of asthmatic children with positive and negative skin test to house dust allergen and non-asthmatic controls were examined. There was no conspicuous difference in mite species distribution among the three groups. Pyroglyphid mites dominate the mite fauna in house dust more than half of which being Dermatophagoides: D. pteronyssinus and D. farinae. There was no statistically significant difference in numbers between the two species and either species could dominate depending on the conditions of the individual houses. The average number of acarina in 0.5 g of fine dust did not differ statistically among the three groups; however, mite number per square meter floor differed between patients with positive skin test and negative skin test. The results suggest that house-cleaning might influence the possible sensitization of children. The genetic distribution of mould fungi in house dust was largely similar to that of airborne fungi. The average number of fungal colonies detected in 0.5 g of dust did not differ statistically among the three groups. Wallemia with its minute spores may cause sensitization but has so far been insufficiently investigated.

Modeling Respiratory Toxicity of Authentic Lunar Dust

NASA Technical Reports Server (NTRS)

Santana, Patricia A.; James, John T.; Lam, Chiu-Wing

2010-01-01

The lunar expeditions of the Apollo operations from the 60 s and early 70 s have generated awareness about lunar dust exposures and their implication towards future lunar explorations. Critical analyses on the reports from the Apollo crew members suggest that lunar dust is a mild respiratory and ocular irritant. Currently, NASA s space toxicology group is functioning with the Lunar Airborne Dust Toxicity Assessment Group (LADTAG) and the National Institute for Occupational Safety and Health (NIOSH) to investigate and examine toxic effects to the respiratory system of rats in order to establish permissible exposure levels (PELs) for human exposure to lunar dust. In collaboration with the space toxicology group, LADTAG and NIOSH the goal of the present research is to analyze dose-response curves from rat exposures seven and twenty-eight days after intrapharyngeal instillations, and model the response using BenchMark Dose Software (BMDS) from the Environmental Protection Agency (EPA). Via this analysis, the relative toxicities of three types of Apollo 14 lunar dust samples and two control dust samples, titanium dioxide (TiO2) and quartz will be determined. This will be executed for several toxicity endpoints such as cell counts and biochemical markers in bronchoaveolar lavage fluid (BALF) harvested from the rats.

The mass-loss return from evolved stars to the Large Magellanic Cloud. V. The GRAMS carbon-star model grid

NASA Astrophysics Data System (ADS)

Srinivasan, S.; Sargent, B. A.; Meixner, M.

2011-08-01

Context. Outflows from asymptotic giant branch (AGB) and red supergiant (RSG) stars inject dust into the interstellar medium. The total rate of dust return provides an important constraint to galactic chemical evolution models. However, this requires detailed radiative transfer (RT) modeling of individual stars, which becomes impractical for large data sets. An alternative approach is to select the best-fit spectral energy distribution (SED) from a grid of dust shell models, allowing for a faster determination of the luminosities and mass-loss rates for entire samples. Aims: We have developed the Grid of RSG and AGB ModelS (GRAMS) to measure the mass-loss return from evolved stars. The models span the range of stellar, dust shell and grain properties relevant to evolved stars. The GRAMS model database will be made available to the scientific community. In this paper we present the carbon-rich AGB model grid and compare our results with photometry and spectra of Large Magellanic Cloud (LMC) carbon stars from the SAGE (Surveying the Agents of Galaxy Evolution) and SAGE-Spec programs. Methods: We generate models for spherically symmetric dust shells using the 2Dust code, with hydrostatic models for the central stars. The model photospheres have effective temperatures between 2600 and 4000 K and luminosities from ~2000 L⊙ to ~40 000 L⊙. Assuming a constant expansion velocity, we explore five values of the inner radius Rin of the dust shell (1.5, 3, 4.5, 7 and 12 Rstar). We fix the outer radius at 1000 Rin. Based on the results from our previous study, we use amorphous carbon dust mixed with 10% silicon carbide by mass. The grain size distribution follows a power-law and an exponential falloff at large sizes. The models span twenty-six values of 11.3 μm optical depth, ranging from 0.001 to 4. For each model, 2Dust calculates the output SED from 0.2 to 200 μm. Results: Over 12 000 models have dust temperatures below 1800 K. For these, we derive synthetic photometry in optical, near-infrared and mid-infrared filters for comparison with available data. We find good agreement with magnitudes and colors observed for LMC carbon-rich and extreme AGB star candidates from the SAGE survey, as well as spectroscopically confirmed carbon stars from the SAGE-Spec study. Our models reproduce the IRAC colors of most of the extreme AGB star candidates, consistent with the expectation that a majority of these enshrouded stars have carbon-rich dust. Finally, we fit the SEDs of some well-studied carbon stars and compare the resulting luminosities and mass-loss rates with those from previous studies. The model grid is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/532/A54

A New Method Using Single-Particle Mass Spectrometry Data to Distinguish Mineral Dust and Biological Aerosols

NASA Astrophysics Data System (ADS)

Al-Mashat, H.; Kristensen, L.; Sultana, C. M.; Prather, K. A.

2016-12-01

The ability to distinguish types of particles present within a cloud is important for determining accurate inputs to climate models. The chemical composition of particles within cloud liquid droplets and ice crystals can have a significant impact on the timing, location, and amount of precipitation that falls. Precipitation efficiency is increased by the presence of ice crystals in clouds, and both mineral dust and biological aerosols have been shown to be effective ice nucleating particles (INPs) in the atmosphere. A current challenge in aerosol science is distinguishing mineral dust and biological material in the analysis of real-time, ambient, single-particle mass spectral data. Single-particle mass spectrometers are capable of measuring the size-resolved chemical composition of individual atmospheric particles. However, there is no consistent analytical method for distinguishing dust and biological aerosols. Sampling and characterization of control samples (i.e. of known identity) of mineral dust and bacteria were performed by the Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) as part of the Fifth Ice Nucleation (FIN01) Workshop at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) facility in Karlsruhe, Germany. Using data collected by the ATOFMS of control samples, a new metric has been developed to classify single particles as dust or biological independent of spectral cluster analysis. This method, involving the use of a ratio of mass spectral peak areas for organic nitrogen and silicates, is easily reproducible and does not rely on extensive knowledge of particle chemistry or the ionization characteristics of mass spectrometers. This represents a step toward rapidly distinguishing particle types responsible for ice nucleation activity during real-time sampling in clouds. The ability to distinguish types of particles present within a cloud is important for determining accurate inputs to climate models. The chemical composition of particles within cloud liquid droplets and ice crystals can have a significant impact on the timing, location, and amount of precipitation that falls. Precipitation efficiency is increased by the presence of ice crystals in clouds, and both mineral dust and biological aerosols have been shown to be effective ice nucleating particles (INPs) in the atmosphere. A current challenge in aerosol science is distinguishing mineral dust and biological material in the analysis of real-time, ambient, single-particle mass spectral data. Single-particle mass spectrometers are capable of measuring the size-resolved chemical composition of individual atmospheric particles. However, there is no consistent analytical method for distinguishing dust and biological aerosols. Sampling and characterization of control samples (i.e. of known identity) of mineral dust and bacteria were performed by the Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) as part of the Fifth Ice Nucleation (FIN01) Workshop at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) facility in Karlsruhe, Germany. Using data collected by the ATOFMS of control samples, a new metric has been developed to classify single particles as dust or biological independent of spectral cluster analysis. This method, involving the use of a ratio of mass spectral peak areas for organic nitrogen and silicates, is easily reproducible and does not rely on extensive knowledge of particle chemistry or the ionization characteristics of mass spectrometers. This represents a step toward rapidly distinguishing particle types responsible for ice nucleation activity during real-time sampling in clouds.

Transformation of arsenic-rich copper smelter flue dust in contrasting soils: A 2-year field experiment.

PubMed

Jarošíková, Alice; Ettler, Vojtěch; Mihaljevič, Martin; Penížek, Vít; Matoušek, Tomáš; Culka, Adam; Drahota, Petr

2018-06-01

Dust emissions from copper smelters processing arsenic-bearing ores represent a risk to soil environments due to the high levels of As and other inorganic contaminants. Using an in situ experiment in four different forest and grassland soils (pH 3.2-8.0) we studied the transformation of As-rich (>50 wt% As) copper smelter dust over 24 months. Double polyamide bags with 1 g of flue dust were buried at different depths in soil pits and in 6-month intervals; then those bags, surrounding soil columns, and soil pore waters were collected and analysed. Dust dissolution was relatively fast during the first 6 months (5-34%), and mass losses attained 52% after 24 months. The key driving forces affecting dust dissolution were not only pH, but also the water percolation/retention in individual soils. Primary arsenolite (As 2 O 3 ) dissolution was responsible for high As release from the dust (to 72%) and substantial increase of As in the soil (to a 56 × increase; to 1500 mg kg -1 ). Despite high arsenolite solubility, this phase persisted in the dust after 2 years of exposure. Mineralogical investigation indicated that mimetite [Pb 5 (AsO 4 ) 3 (Cl,OH)], unidentified complex Ca-Pb-Fe-Zn arsenates, and Fe oxyhydroxides partly controlled the mobility of As and other metal(loid)s. Compared to As, other less abundant contaminants (Bi, Cu, Pb, Sb, Zn) were released into the soil to a lesser extent (8-40% of total). The relatively high mobility of As in the soil can be seen from decreases of bulk As concentrations after spring snowmelt, high water-extractable fractions with up to ∼50% of As(III) in extracts, and high As concentrations in soil pore waters. Results indicate that efficient controls of emissions from copper smelters and flue dust disposal sites are needed to prevent extensive contamination of nearby soils by persistent As. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Growth Response of Two Diatom Species to Atmospheric Dust from the Last Glacial Maximum.

PubMed

Conway, Tim M; Hoffmann, Linn J; Breitbarth, Eike; Strzepek, Robert F; Wolff, Eric W

2016-01-01

Relief of iron (Fe) limitation in the surface Southern Ocean has been suggested as one driver of the regular glacial-interglacial cycles in atmospheric carbon dioxide (CO2). The proposed cause is enhanced deposition of Fe-bearing atmospheric dust to the oceans during glacial intervals, with consequent effects on export production and the carbon cycle. However, understanding the role of enhanced atmospheric Fe supply in biogeochemical cycles is limited by knowledge of the fluxes and 'bioavailability' of atmospheric Fe during glacial intervals. Here, we assess the effect of Fe fertilization by dust, dry-extracted from the Last Glacial Maximum portion of the EPICA Dome C Antarctic ice core, on the Antarctic diatom species Eucampia antarctica and Proboscia inermis. Both species showed strong but differing reactions to dust addition. E. antarctica increased cell number (3880 vs. 786 cells mL-1), chlorophyll a (51 vs. 3.9 μg mL-1) and particulate organic carbon (POC; 1.68 vs. 0.28 μg mL-1) production in response to dust compared to controls. P. inermis did not increase cell number in response to dust, but chlorophyll a and POC per cell both strongly increased compared to controls (39 vs. 15 and 2.13 vs. 0.95 ng cell-1 respectively). The net result of both responses was a greater production of POC and chlorophyll a, as well as decreased Si:C and Si:N incorporation ratios within cells. However, E, antarctica decreased silicate uptake for the same nitrate and carbon uptake, while P. inermis increased carbon and nitrate uptake for the same silicate uptake. This suggests that nutrient utilization changes in response to Fe addition could be driven by different underlying mechanisms between different diatom species. Enhanced supply of atmospheric dust to the surface ocean during glacial intervals could therefore have driven nutrient-utilization changes which could permit greater carbon fixation for lower silica utilization. Additionally, both species responded more strongly to lower amounts of direct Fe chloride addition than they did to dust, suggesting that not all the Fe released from dust was in a bioavailable form available for uptake by diatoms.

The Growth Response of Two Diatom Species to Atmospheric Dust from the Last Glacial Maximum

PubMed Central

Hoffmann, Linn J.; Breitbarth, Eike; Strzepek, Robert F.; Wolff, Eric W.

2016-01-01

Relief of iron (Fe) limitation in the surface Southern Ocean has been suggested as one driver of the regular glacial-interglacial cycles in atmospheric carbon dioxide (CO2). The proposed cause is enhanced deposition of Fe-bearing atmospheric dust to the oceans during glacial intervals, with consequent effects on export production and the carbon cycle. However, understanding the role of enhanced atmospheric Fe supply in biogeochemical cycles is limited by knowledge of the fluxes and ‘bioavailability’ of atmospheric Fe during glacial intervals. Here, we assess the effect of Fe fertilization by dust, dry-extracted from the Last Glacial Maximum portion of the EPICA Dome C Antarctic ice core, on the Antarctic diatom species Eucampia antarctica and Proboscia inermis. Both species showed strong but differing reactions to dust addition. E. antarctica increased cell number (3880 vs. 786 cells mL-1), chlorophyll a (51 vs. 3.9 μg mL-1) and particulate organic carbon (POC; 1.68 vs. 0.28 μg mL-1) production in response to dust compared to controls. P. inermis did not increase cell number in response to dust, but chlorophyll a and POC per cell both strongly increased compared to controls (39 vs. 15 and 2.13 vs. 0.95 ng cell-1 respectively). The net result of both responses was a greater production of POC and chlorophyll a, as well as decreased Si:C and Si:N incorporation ratios within cells. However, E, antarctica decreased silicate uptake for the same nitrate and carbon uptake, while P. inermis increased carbon and nitrate uptake for the same silicate uptake. This suggests that nutrient utilization changes in response to Fe addition could be driven by different underlying mechanisms between different diatom species. Enhanced supply of atmospheric dust to the surface ocean during glacial intervals could therefore have driven nutrient-utilization changes which could permit greater carbon fixation for lower silica utilization. Additionally, both species responded more strongly to lower amounts of direct Fe chloride addition than they did to dust, suggesting that not all the Fe released from dust was in a bioavailable form available for uptake by diatoms. PMID:27384948

Hygroscopicity of mineral dust particles: Roles of chemical mixing state and hygroscopic conversion timescale

NASA Astrophysics Data System (ADS)

Sullivan, R. C.; Moore, M. J.; Petters, M. D.; Laskin, A.; Roberts, G. C.; Kreidenweis, S. M.; Prather, K. A.

2009-05-01

Our laboratory investigations of mineral dust particle hygroscopicity are motivated by field observations of the atmospheric processing of dust. During ACE-Asia we observed sulphate and nitrate to be strongly segregated from each other in individual aged Asian dust particles. CCN activation curves of pure calcium minerals as proxies for fresh (calcium carbonate) and aged (calcium sulphate, nitrate, chloride) dust indicate that this mixing state would cause a large fraction of aged dust particles to remain poor warm cloud nucleation potential, contrary to previous assumptions. The enrichment of oxalic acid in calcium-rich dust particles could have similar effects due to the formation of insoluble calcium oxalate. Soluble calcium nitrate and chloride reaction products are hygroscopic and will transform mineral dust into excellent CCN. Generating insoluble mineral particles wet by atomization produced particles with much higher hygroscopicity then when resuspended dry. The atomized particles are likely composed of dissolved residuals and do not properly reflect the chemistry of dry mineral powders. Aerosol flow tube experiments were employed to study the conversion of calcium carbonate into calcium nitrate via heterogeneous reaction with nitric acid, with simultaneous measurements of the reacted particles' chemistry and hygroscopicity. The timescale for this hygroscopic conversion was found to occur on the order of a few hours under tropospheric conditions. This implies that the conversion of non-hygroscopic calcite- containing dust into hygroscopic particles will be controlled by the availability of nitric acid, and not by the atmospheric residence time. Results from recent investigations of the effect of secondary coatings on the ice nucleation properties of dust particles will also be presented. The cloud formation potential of aged dust particles depends on both the quantity and form of the secondary species that have reacted or mixed with the dust. These results have important implications for the treatment of mineral dust particles in global chemistry and climate models.

Dust sources and atmospheric circulation in concert controlling Saharan dust emission and transport towards the Western Mediterranean Basin

NASA Astrophysics Data System (ADS)

Schepanski, Kerstin; Mallet, Marc; Heinold, Bernd; Ulrich, Max

2017-04-01

Dust transported from north African source regions towards Europe is a ubiquitous phenomenon in the Mediterranean region, a geographic region that is in part densely populated. Besides its impacts on the atmospheric radiation budget, dust suspended in the atmosphere results in reduced air quality, which is generally sensed as a reduction in quality of life. Furthermore, the exposure to dust aerosols enhances the prevalence of respiratory diseases, which reduces the general human wellbeing, and ultimately results in an increased loss of working hours due to illness and hospitalization rates. Characteristics of the atmospheric dust life cycle that determine dust transport will be presented with focus on the ChArMEx special observation period in June and July 2013 using the atmosphere-dust model COSMO-MUSCAT (COSMO: Consortium for Small-scale MOdeling; MUSCAT: MUltiScale Chemistry Aerosol Transport Model). Modes of atmospheric circulation were identified from empirical orthogonal function (EOF) analysis of the geopotential height at 850 hPa for summer 2013 and compared to EOFs calculated from 1979-2015 ERA-Interim reanalysis. Generally, two different phases were identified. They are related to the eastward propagation of the subtropical ridge into the Mediterranean basin, the position of the Saharan heat low, and the predominant Iberian heat low. The relation of these centres of action illustrates a dipole pattern for enhanced (reduced) dust emission fluxes, stronger (weaker) meridional dust transport, and consequent increase (decrease) atmospheric dust concentrations and deposition fluxes. In concert, the results from this study aim at illustrating the relevance of knowing the dust source locations in concert with the atmospheric circulation. Ultimately, this study addresses the question of what is finally transported towards the Mediterranean basin and Europe from which source regions - and fostered by which atmospheric circulation pattern. Outcomes from this study contribute to the understanding of varying atmospheric mineral dust contributions to the aerosol burden affecting populated areas around Europe.

The cytotoxic and genetoxic effects of dust and soil samples from E-waste recycling area on L02 cells.

PubMed

Wang, Liulin; Hou, Meiling; An, Jing; Zhong, Yufang; Wang, Xuetong; Wang, Yangjun; Wu, Minghong; Bi, Xinhui; Sheng, Guoying; Fu, Jiamo

2011-10-01

Electrical and electronic waste (E-waste) has now become the fastest growing solid waste around the world. Primitive recycling operations for E-waste have resulted in severe contamination of toxic metals and organic chemicals in the related areas. In this study, six dust and soil samples collected from E-waste recycling workshops and open-burning sites in Longtang were analyzed to investigate their cytotoxicity and genotoxicity on L02 cells. These six samples were: dust No. 1 collected at the gate of the workshop; dust No. 2 collected from air conditioning compressor dismantling site; dust No. 3 collected from where some motors, wires, and aluminium products since the 1980s were dismantled; soil No. 1 collected at the circuit board acid washing site; soil No. 2 collected from a wire open-burning site; soil No. 3 collected near a fiber open-burning site. At the same time, two control soil samples were collected from farmlands approximately 8 km away from the dismantling workshops. The results showed that all of these samples could inhibit cell proliferation and cause cell membrane lesion, among which dust No. 3 and soil No. 2 had the strongest toxicity. Moreover, the comet assay showed that the dust No. 3 had the most significant capability to cause DNA single-strand beaks (SSB), while the road dust (dust No. 1) collected at the gate of the workshop, a relatively farer site, showed the slightest capability to induce DNA SSB. The intracellular reactive oxygen species (ROS) detection showed that ROS level was elevated with the increase of dust and soil samples concentration. Dust No. 3 and soil No. 2 had the highest ROS level, followed by dust No. 2 and 1, soil No. 3 and 1. All of the above results indicated that polluted soil and dust from the E-waste area had cytotoxicity and genotoxicity on L02 cells, the mechanism might involve the increased ROS level and consequent DNA SSB.

Laboratory investigation of dust impacts on antennas in space

NASA Astrophysics Data System (ADS)

Drake, K.; Gruen, E.; Malaspina, D.; Sternovsky, Z.

2013-12-01

We are performing calibration measurements in our laboratory using a dust accelerator to understand the mechanisms how dust impact generated plasma clouds couple into electric field antennas on spacecraft. The S/WAVES electric field instruments on board the twin STEREO spacecraft observed short duration (milliseconds), large amplitude (> 15 mV) voltage spikes associated with the impact of high velocity dust particles on the spacecraft [St. Cyr et al., 2009, MeyerVernet et al, 2009a, Zaslavsky et al., 2012]. These sharp spikes have been attributed to plasma clouds generated by the impact ionization of high velocity dust particles. The high count rate has lead to the interpretation that S/WAVES is detecting nanometer sized dust particles (nano-dust) generated in the inner solar system and accelerated to close to solar wind velocities before impacting the spacecraft at 1 AU. The S/WAVES nano-dust interpretation is currently based on an incomplete understanding of the charge generated from relevant materials and the coupling mechanism between the plasma cloud and the electric field instrument. Calibration measurements are performed at the dust accelerator facility at the University of Colorado to investigate the effect of various impact parameters on the signals measured by the electric field instrument. The dust accelerator facility allows experimental control over target materials, size (micron to sub-micron), and velocity (1-60 km/s) of impacting dust particles, geometry of the impact, the ';spacecraft' potential, and the presence or absence of photoelectrons, allowing each coupling factor to be isolated and quantified. As the first step in this effort, we measure the impact charge generation for materials relevant for the STEREO spacecraft.

Mesoscale behavior study of collector aggregations in a wet dust scrubber.

PubMed

Li, Xiaochuan; Wu, Xiang; Hu, Haibin; Jiang, Shuguang; Wei, Tao; Wang, Dongxue

2018-01-01

In order to address the bottleneck problem of low fine-particle removal efficiency of self-excited dust scrubbers, this paper is focused on the influence of the intermittent gas-liquid two-phase flow on the mesoscale behavior of collector aggregations. The latter is investigated by the application of high-speed dynamic image technology to the self-excited dust scrubber experimental setup. The real-time-scale monitoring of the dust removal process is provided to clarify its operating mechanism at the mesoscale level. The results obtained show that particulate capturing in self-excited dust scrubber is provided by liquid droplets, liquid films/curtains, bubbles, and their aggregations. Complex spatial and temporal structures are intrinsic to each kind of collector morphology, and these are considered as the major factors controlling the dust removal mechanism of self-excited dust scrubbers. For the specific parameters of gas-liquid two-phase flow under study, the evolution patterns of particular collectors reflect the intrinsic, intermittent, and complex characteristics of the temporal structure. The intermittent initiation of the collector and the air hole formation-collapse cyclic processes provide time and space for the fine dust to escape from being trapped by the collectors. The above mesoscale experimental data provide more insight into the factors reducing the dust removal efficiency of self-excited dust scrubbers. This paper focuses on the reconsideration of the capturer aggregations of self-excited dust scrubbers from the mesoscale. Complex structures in time and space scales exist in each kind of capturer morphology. With changes of operating parameters, the morphology and spatial distributions of capturers diversely change. The change of the capturer over time presents remarkable, intermittent, and complex characteristics of the temporal structure.

Role of Surface Wind and Vegetation Cover in Multi-decadal Variations of Dust Emission in the Sahara and Sahel

NASA Technical Reports Server (NTRS)

Kim, Dong; Chin, Mian; Remer, Lorraine A.; Diehl, Thomas L.; Bian, Huisheng; Yu, Hongbin; Brown, Molly E.; Stockwell, William R.

2016-01-01

North Africa, the world's largest dust source, is non-uniform, consisting of a permanently arid region (Sahara), a semi-arid region (Sahel), and a relatively moist vegetated region (Savanna), each with very different rainfall patterns and surface conditions. This study aims to better understand the controlling factors that determine the variation of dust emission in North Africa over a 27-year period from 1982 to 2008, using observational data and model simulations. The results show that the model-derived Saharan dust emission is only correlated with the 10-m winds (W10m) obtained from reanalysis data, but the model-derived Sahel dust emission is correlated with both W10m and the Normalized Difference Vegetation Index (NDVI) that is obtained from satellite. While the Saharan dust accounts for 82 of the continental North Africa dust emission (1340-1570 Tg year(exp -1) in the 27-year average, the Sahel accounts for 17 with a larger seasonal and inter-annual variation (230-380 Tg year(exp -1), contributing about a quarter of the transatlantic dust transported to the northern part of South America. The decreasing dust emission trend over the 27-year period is highly correlated with W10m over the Sahara (R equals 0.92). Over the Sahel, the dust emission is correlated with W10m (R 0.69) but is also anti-correlated with the trend of NDVI (R equals 0.65). W10m is decreasing over both the Sahara and the Sahel between 1982 and 2008, and the trends are correlated (R equals 0.53), suggesting that Saharan Sahelian surface winds are a coupled system, driving the inter-annual variation of dust emission.

Reducing risk of house dust mite and cockroach allergen exposure in inner-city children with asthma.

PubMed

Kuster, P A

1996-01-01

Asthma prevalence among disadvantaged and minority children is disproportionately higher in inner-city populations. Environmental allergen exposure, particularly that of house dust mites and cockroaches, is known to contribute to asthma exacerbations in children. Environmental control of these particular triggers is a necessary component of asthma education and should be incorporated into the teaching plan for these children. The costs surrounding environmental control may not be within the means of many families living in urban, inner-city environments; therefore nurses should offer families creative ideas and cost effective suggestions for controlling environmental triggers.

Lunar Dust Mitigation Technology Development

NASA Technical Reports Server (NTRS)

Hyatt, Mark J.; Deluane, Paul B.

2008-01-01

NASA s plans for implementing the Vision for Space Exploration include returning to the moon as a stepping stone for further exploration of Mars, and beyond. Dust on the lunar surface has a ubiquitous presence which must be explicitly addressed during upcoming human lunar exploration missions. While the operational challenges attributable to dust during the Apollo missions did not prove critical, the comparatively long duration of impending missions presents a different challenge. Near term plans to revisit the moon places a primary emphasis on characterization and mitigation of lunar dust. Comprised of regolith particles ranging in size from tens of nanometers to microns, lunar dust is a manifestation of the complex interaction of the lunar soil with multiple mechanical, electrical, and gravitational effects. The environmental and anthropogenic factors effecting the perturbation, transport, and deposition of lunar dust must be studied in order to mitigate it s potentially harmful effects on exploration systems. This paper presents the current perspective and implementation of dust knowledge management and integration, and mitigation technology development activities within NASA s Exploration Technology Development Program. This work is presented within the context of the Constellation Program s Integrated Lunar Dust Management Strategy. The Lunar Dust Mitigation Technology Development project has been implemented within the ETDP. Project scope and plans will be presented, along with a a perspective on lessons learned from Apollo and forensics engineering studies of Apollo hardware. This paper further outlines the scientific basis for lunar dust behavior, it s characteristics and potential effects, and surveys several potential strategies for its control and mitigation both for lunar surface operations and within the working volumes of a lunar outpost.

Sensitivity of WRF-chem predictions to dust source function specification in West Asia

NASA Astrophysics Data System (ADS)

Nabavi, Seyed Omid; Haimberger, Leopold; Samimi, Cyrus

2017-02-01

Dust storms tend to form in sparsely populated areas covered by only few observations. Dust source maps, known as source functions, are used in dust models to allocate a certain potential of dust release to each place. Recent research showed that the well known Ginoux source function (GSF), currently used in Weather Research and Forecasting Model coupled with Chemistry (WRF-chem), exhibits large errors over some regions in West Asia, particularly near the IRAQ/Syrian border. This study aims to improve the specification of this critical part of dust forecasts. A new source function based on multi-year analysis of satellite observations, called West Asia source function (WASF), is therefore proposed to raise the quality of WRF-chem predictions in the region. WASF has been implemented in three dust schemes of WRF-chem. Remotely sensed and ground-based observations have been used to verify the horizontal and vertical extent and location of simulated dust clouds. Results indicate that WRF-chem performance is significantly improved in many areas after the implementation of WASF. The modified runs (long term simulations over the summers 2008-2012, using nudging) have yielded an average increase of Spearman correlation between observed and forecast aerosol optical thickness by 12-16 percent points compared to control runs with standard source functions. They even outperform MACC and DREAM dust simulations over many dust source regions. However, the quality of the forecasts decreased with distance from sources, probably due to deficiencies in the transport and deposition characteristics of the forecast model in these areas.

The Electrostatic Environments of the Moon and Mars: Implications for Human Missions

NASA Technical Reports Server (NTRS)

Calle, Carlos I.; Mackey, Paul J.; Johansen, Michael R.; Hogue, Michael D.; Phillips, James; Cox, Rachel E.

2016-01-01

Lacking a substantial atmosphere, the moon is exposed to the full spectrum of solar radiation as well as to cosmic rays. Electrostatically, the moon is a charged body in a plasma. A Debye sheet meters high on the dayside of the moon and kilometers high on the night side envelops the moon. This sheet isolates the lunar surface from high energy particles coming from the sun. The electrostatic environment on Mars is controlled by its ever present atmospheric dust. Dust devils and dust storms tribocharge this dust. Theoretical studies predict that lightning and/or glow discharges should be present on Mars, but none have been directly observed. Experiments are planned to shed light on this issue.