Promoting early exposure monitoring for respirable crystalline silica: Taking the laboratory to the mine site

PubMed Central

Cauda, Emanuele; Miller, Arthur; Drake, Pamela

2017-01-01

The exposure to respirable crystalline silica (RCS) in the mining industry is a recognized occupational hazard. The assessment and monitoring of the exposure to RCS is limited by two main factors: (1) variability of the silica percent in the mining dust and (2) lengthy off-site laboratory analysis of collected samples. The monitoring of respirable dust via traditional or real-time techniques is not adequate. A solution for on-site quantification of RCS in dust samples is being investigated by the Office of Mine Safety and Health Research, a division of the National Institute for Occupational Safety and Health. The use of portable Fourier transform infrared analyzers in conjunction with a direct-on-filter analysis approach is proposed. The progress made so far, the necessary steps in progress, and the application of the monitoring solution to a small data set is presented. When developed, the solution will allow operators to estimate RCS immediately after sampling, resulting in timelier monitoring of RCS for self-assessment of compliance at the end of the shift, more effective engineering monitoring, and better evaluation of control technologies. PMID:26558490

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.

MicroMED: a dust particle counter for the characterization of airborne dust close to the surface of Mars

NASA Astrophysics Data System (ADS)

Cozzolino, Fabio; Esposito, Francesca; Molfese, Cesare; Cortecchia, Fausto; Saggin, Bortolino; D'amato, Francesco

2015-04-01

Monitoring of airborne dust is very important in planetary climatology. Indeed, dust absorbs and scatter solar and thermal radiation, severely affecting atmospheric thermal structure, balance and dynamics (in terms of circulations). Wind-driven blowing of sand and dust is also responsible for shaping planetary surfaces through the formation of sand dunes and ripples, the erosion of rocks, and the creation and transport of soil particles. Dust is permanently present in the atmosphere of Mars and its amount varies with seasons. During regional or global dust storms, more than 80% of the incoming sunlight is absorbed by dust causing an intense atmospheric heating. Airborne dust is therefore a crucial climate component on Mars which impacts atmospheric circulations at all scales. Main dust parameters influencing the atmosphere heating are size distribution, abundance, albedo, single scattering phase function, imaginary part of the index of refraction. Moreover, major improvements of Mars climate models require, in addition to the standard meteorological parameters, quantitative information about dust lifting, transport and removal mechanisms. In this context, two major quantities need to be measured for the dust source to be understood: surface flux and granulometry. While many observations have constrained the size distribution of the dust haze seen from the orbit, it is still not known what the primary airborne dust (e.g. the recently lifted dust) is made of, size-wise. MicroMED has been designed to fill this gap. It will measure the abundance and size distribution of dust, not in the atmospheric column, but close to the surface, where dust is lifted, so to be able to monitor dust injection into the atmosphere. This has never been performed in Mars and other planets exploration. MicroMED is an Optical Particle Counter, analyzing light scattered from single dust particles to measure their size and abundance. A proper fluid-dynamic system, including a pump and a sampling head, allows the sampling of Martian atmosphere with embedded dust. The captured dust grains are detected by an Optical System and then ejected into the atmosphere. MicroMED is a miniaturization of the instrument MEDUSA, developed for the Humboldt payload of the ExoMars mission. An Elegant Breadboard has been developed and tested and successfully demonstrates the instrument performances. The design and performance test results will be discussed.

Monitoring An Intensive Dust Event over Northern China Using Multi-satellite Observation

NASA Astrophysics Data System (ADS)

She, L.; Xue, Y.; Guang, J.; Mei, L.; Che, Y.; Fan, C.; Xie, Y.

2017-12-01

The deserts in western/northern China are one of the major mineral dust source regions of the world. Large amount of dust are emitted and blown east and southeast, especially in spring. An intensive dust event occurred over Northern China during May 3 - 8, 2017. The dust storms came from deserts in China and Mongolia. Due to the long-distance transport, more than ten provinces were affected by this dust event, several provinces occurred strong dust storm. In this study, multi-satellite data were employed to analyse the spatial-temporal evolution and dynamic transport behaviour of the dust plume, especially the geostationary satellite data - Himawari8 Advanced Himawari Imager (AHI) data. AHI data was used to estimate hourly Aerosol Optical Depth (AOD) to monitoring the aerosol distribution as well as the dust plume movements, as the dust storms often characterized by high AOD. A simple dust index was also calculated based on AHI VIS and TIR data to estimate the dust intensity. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data and the Ozone Monitoring Instrument (OMI) Aerosol Index were used as additional data sources to monitor the dust vertical distribution and provide independent information of dust presence. MODIS aerosol product and AERONET aerosol measurements were compared with the AHI retrieved AODs, the comparisons show a good agreement. The dust index was compared with the ground measurements as well as the corresponding RGB image. Simulations from HYSPLIT back-trajectory analysis shows similar temporal variation with the calculated AOD and dust index of the dust plume. Those comparisons with other satellite products and ground measurements suggested both the calculated AOD and dust index well depicted the dust events compared.

Quantitative detection of mass concentration of sand-dust storms via wind-profiling radar and analysis of Z- M relationship

NASA Astrophysics Data System (ADS)

Wang, Minzhong; Ming, Hu; Ruan, Zheng; Gao, Lianhui; Yang, Di

2018-02-01

With the aim to achieve quantitative monitoring of sand-dust storms in real time, wind-profiling radar is applied to monitor and study the process of four sand-dust storms in the Tazhong area of the Taklimakan Desert. Through evaluation and analysis of the spatial-temporal distribution of reflectivity factor, it is found that reflectivity factor ranges from 2 to 18 dBz under sand-dust storm weather. Using echo power spectrum of radar vertical beams, sand-dust particle spectrum and sand-dust mass concentration at the altitude of 600 ˜ 1500 m are retrieved. This study shows that sand-dust mass concentration reaches 700 μg/m3 under blowing sand weather, 2000 μg/m3 under sand-dust storm weather, and 400 μg/m3 under floating dust weather. The following equations are established to represent the relationship between the reflectivity factor and sand-dust mass concentration: Z = 20713.5 M 0.995 under floating dust weather, Z = 22988.3 M 1.006 under blowing sand weather, and Z = 24584.2 M 1.013 under sand-dust storm weather. The retrieval results from this paper are almost consistent with previous monitoring results achieved by former researchers; thus, it is implied that wind-profiling radar can be used as a new reference device to quantitatively monitor sand-dust storms.

Monitoring pulsating giant stars in M33: star formation history and chemical enrichment

NASA Astrophysics Data System (ADS)

Javadi, A.; van Loon, J. Th

2017-06-01

We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). A new method has been developed by us to use pulsating giant stars to reconstruct the star formation history of galaxies over cosmological time as well as using them to map the dust production across their host galaxies. In first Instance the central square kiloparsec of M33 was monitored and long period variable stars (LPVs) were identified. We give evidence of two epochs of a star formation rate enhanced by a factor of a few. These stars are also important dust factories, we measure their dust production rates from a combination of our data with Spitzer Space Telescope mid-IR photometry. Then the monitoring survey was expanded to cover a much larger part of M33 including spiral arms. Here we present our methodology and describe results for the central square kiloparsec of M33 [1-4] and disc of M33 [5-8].

Development of Laser Scanner for Full Cross-Sectional Deformation Monitoring of Underground Gateroads

PubMed Central

Yang, Qianlong; Zhang, Zhenyu; Liu, Xiaoqian; Ma, Shuqi

2017-01-01

The deformation of underground gateroads tends to be asymmetric and complex. Traditional instrumentation fails to accurately and conveniently monitor the full cross-sectional deformation of underground gateroads. Here, a full cross-sectional laser scanner was developed, together with a visualization software package. The developed system used a polar coordinate measuring method and the full cross-sectional measurement was shown by 360° rotation of a laser sensor driven by an electrical motor. Later on, the potential impact of gateroad wall flatness, roughness, and geometrical profile, as well as coal dust environment on the performance of the developed laser scanner will be evaluated. The study shows that high-level flatness is favorable in the application of the developed full cross-sectional deformation monitoring system. For a smooth surface of gateroad, the sensor cannot receive reflected light when the incidence angle of laser beam is large, causing data loss. Conversely, the roughness surface shows its nature as the diffuse reflection light can be received by the sensor. With regards to coal dust in the measurement environment, fine particles of floating coal dust in the air can lead to the loss of measurement data to some extent, due to scattering of the laser beam. PMID:28590449

Climate Change Implications and Use of Early Warning Systems for Global Dust Storms

NASA Astrophysics Data System (ADS)

Harriman, L.

2014-12-01

Increased changes in land cover and global climate have led to increased frequency and/or intensity of dust storms in some regions of the world. Early detection and warning of dust storms, in conjunction with effective and widespread information broadcasts, will be essential to the prevention and mitigation of future risks and impacts to people and the environment. Since frequency and intensity of dust storms can vary from region to region, there is a demonstrated need for more research to be conducted over longer periods of time to analyze trends of dust storm events [1]. Dust storms impact their origin area, but also land, water and people a great distance away from where dust finally settles [2, 3]. These transboundary movements and accompanying impacts further warrant the need for global collaboration to help predict the onset, duration and path of a dust storm. Early warning systems can help communicate when a dust storm is occurring, the projected intensity of the dust storm and its anticipated physical impact over a particular geographic area. Development of regional dust storm models, such as CUACE/Dust for East Asia, and monitoring networks, like the Sand and Dust Storm Warning Network operated by the World Meteorological Organization, and the use of remote sensing and satellite imagery derived products [4], including MODIS, are currently being incorporated into early warning and monitoring initiatives. However, to increase future certainty of impacts of dust storms on vulnerable populations and ecosystems, more research is needed to analyze the influences of human activities, seasonal variations and long-term climatic patterns on dust storm generation, movement and impact. Sources: [1] Goudie, A.S. (2009), Dust storms: recent developments, J Environ. Manage., 90. [2] Lee, H., and Liu, C. (2004), Coping with dust storm events: information, impacts, and policymaking in Taiwan, TAO, 15(5). [3] Marx, S.K., McGowan, H.A., and Balz, K.S. (2009), Long-range dust transport from eastern Australia: a proxy for Holocene aridity and ENSO-type climate variability, Earth Planet Sci. Lett., 282. [4] Kimura, R. (2012), Factors contributing to dust storms in source regions producing the yellow-sand phenomena observed in Japan from 1993 to 2002, J. Arid Environ. 80

'Nuisance Dust' - a Case for Recalibration?

NASA Astrophysics Data System (ADS)

Datson, Hugh; Marker, Brian

2013-04-01

This paper considers the case for a review and recalibration of limit values and acceptability criteria for 'nuisance dust', a widely encountered but poorly defined and regulated aspect of particulate matter pollution. Specific dust fractions such as PM10 and asbestiforms are well characterised and have limit values enshrined in legislation. National, and international, limit values for acceptable concentrations of PM10 and other fractions of particulate matter have been defined and agreed. In the United Kingdom (UK), these apply to both public and workplace exposures. By contrast, there is no standard definition or universal criteria against which acceptable levels for 'nuisance dust' can be assessed. This has implications for land-use planning and resource utilisation. Without meaningful limit values, inappropriate development might take place too near to residential dwellings or land containing economically important mineral resources may be effectively sterilised. Furthermore, the expression 'nuisance dust' is unhelpful in that 'nuisance' has a specific meaning in environmental law whilst 'nuisance dust' is often taken to mean 'generally visible particulate matter'. As such, it is associated with the social and broader environmental impacts of particulate matter. PM10 concentrations are usually expressed as a mass concentration over time. These can be determined using a range of techniques. While results from different instruments are generally comparable, data obtained from alternative methods for measuring 'nuisance dust' are rarely interchangeable. In the UK, many of the methods typically used are derived from approaches developed under the HMIP (Her Majesty's Inspectorate of Pollution) regime in the 1960s onwards. Typical methods for 'nuisance dust' sampling focus on measurement of dust mass (from the weight of dust collected in an open container over time) or dust soiling (from loss of reflectance and or obscuration of a surface discoloured by dust over time). 'Custom and practice' acceptance criteria for dust samples obtained by mass or soiling techniques have been developed and are widely applied even though they were not necessarily calibrated thoroughly and have not been reviewed recently. Furthermore, as sampling techniques have evolved, criteria developed for one method have been adapted for another. Criteria and limit values have sometimes been based on an insufficient knowledge of sampler characteristics. Ideally, limit values should be calibrated for the locality to take differences in dust density and visibility into account. Work is needed on the definition of criteria and limit values, and sampling practices for coarse dust fractions, followed by discussion of good practices for securing effective monitoring that is proportionate and fit for purpose. With social changes and the evolution of environmental controls since the 1960s, the public perception of 'nuisance dust' has changed and needs to be addressed by reviewing existing thresholds in relation to the range of monitoring devices currently in use.

Dust measurements in tokamaks (invited).

PubMed

Rudakov, D L; Yu, J H; Boedo, J A; Hollmann, E M; Krasheninnikov, S I; Moyer, R A; Muller, S H; Pigarov, A Yu; Rosenberg, M; Smirnov, R D; West, W P; Boivin, R L; Bray, B D; Brooks, N H; Hyatt, A W; Wong, C P C; Roquemore, A L; Skinner, C H; Solomon, W M; Ratynskaia, S; Fenstermacher, M E; Groth, M; Lasnier, C J; McLean, A G; Stangeby, P C

2008-10-01

Dust production and accumulation present potential safety and operational issues for the ITER. Dust diagnostics can be divided into two groups: diagnostics of dust on surfaces and diagnostics of dust in plasma. Diagnostics from both groups are employed in contemporary tokamaks; new diagnostics suitable for ITER are also being developed and tested. Dust accumulation in ITER is likely to occur in hidden areas, e.g., between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In the DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering is able to resolve particles between 0.16 and 1.6 microm in diameter; using these data the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in two-dimension with a single camera or three-dimension using multiple cameras, but determination of particle size is challenging. In order to calibrate diagnostics and benchmark dust dynamics modeling, precharacterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase in carbon line (CI, CII, C(2) dimer) and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.

Can dust emission mechanisms be determined from field measurements?

NASA Astrophysics Data System (ADS)

Klose, Martina; Webb, Nicholas; Gill, Thomas E.; Van Pelt, Scott; Okin, Gregory

2017-04-01

Field observations are needed to develop and test theories on dust emission for use in dust modeling systems. The dust emission mechanism (aerodynamic entrainment, saltation bombardment, aggregate disintegration) as well as the amount and particle-size distribution of emitted dust may vary under sediment supply- and transport-limited conditions. This variability, which is caused by heterogeneity of the surface and the atmosphere, cannot be fully captured in either field measurements or models. However, uncertainty in dust emission modeling can be reduced through more detailed observational data on the dust emission mechanism itself. To date, most measurements do not provide enough information to allow for a determination of the mechanisms leading to dust emission and often focus on a small variety of soil and atmospheric settings. Additionally, data sets are often not directly comparable due to different measurement setups. As a consequence, the calibration of dust emission schemes has so far relied on a selective set of observations, which leads to an idealization of the emission process in models and thus affects dust budget estimates. Here, we will present results of a study which aims to decipher the dust emission mechanism from field measurements as an input for future model development. Detailed field measurements are conducted, which allow for a comparison of dust emission for different surface and atmospheric conditions. Measurements include monitoring of the surface, loose erodible material, transported sediment, and meteorological data, and are conducted in different environmental settings in the southwestern United States. Based on the field measurements, a method is developed to differentiate between the different dust emission mechanisms.

Optical method for continuous monitoring of dust deposition in mine's entry / Optyczna metoda ciągłego pomiaru intensywności osiadania pyłu węglowego w wyrobisku górniczym

NASA Astrophysics Data System (ADS)

2012-12-01

The paper presents factors determining dust explosion hazards occurring in underground hard coal mines. The authors described the mechanism of transport and deposition of dust in mines entries and previous research on this topic. The paper presents a method of determination of depositing dust distribution during mining and presents the way to use it to assess coal dust explosion risk. The presented method of calculating the intensity of coal dust deposition is based on continuous monitoring of coal dust concentrations with use of optical sensors. Mathematical model of the distribution of the average coal dust concentration was created. Presented method allows to calculate the intensity of coal dust deposition in a continuous manner. Additionally, the authors presented the PŁ-2 stationary optical dust sampler, used in the study, connected to the monitoring system in the mine. The article features the results of studies conducted in the return air courses of the active longwalls, and the results of calculations of dust deposition intensity carried out with the use of the presented method.

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

Rudakov, D. L.; Yu, J. H.; Boedo, J. A.

Dust production and accumulation present potential safety and operational issues for the ITER. Dust diagnostics can be divided into two groups: diagnostics of dust on surfaces and diagnostics of dust in plasma. Diagnostics from both groups are employed in contemporary tokamaks; new diagnostics suitable for ITER are also being developed and tested. Dust accumulation in ITER is likely to occur in hidden areas, e.g., between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In the DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers,more » visible imaging, and spectroscopy. Laser scattering is able to resolve particles between 0.16 and 1.6 {mu}m in diameter; using these data the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in two-dimension with a single camera or three-dimension using multiple cameras, but determination of particle size is challenging. In order to calibrate diagnostics and benchmark dust dynamics modeling, precharacterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase in carbon line (CI, CII, C{sub 2} dimer) and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.« less

Quantifying Anthropogenic Dust Emissions

NASA Astrophysics Data System (ADS)

Webb, Nicholas P.; Pierre, Caroline

2018-02-01

Anthropogenic land use and land cover change, including local environmental disturbances, moderate rates of wind-driven soil erosion and dust emission. These human-dust cycle interactions impact ecosystems and agricultural production, air quality, human health, biogeochemical cycles, and climate. While the impacts of land use activities and land management on aeolian processes can be profound, the interactions are often complex and assessments of anthropogenic dust loads at all scales remain highly uncertain. Here, we critically review the drivers of anthropogenic dust emission and current evaluation approaches. We then identify and describe opportunities to: (1) develop new conceptual frameworks and interdisciplinary approaches that draw on ecological state-and-transition models to improve the accuracy and relevance of assessments of anthropogenic dust emissions; (2) improve model fidelity and capacity for change detection to quantify anthropogenic impacts on aeolian processes; and (3) enhance field research and monitoring networks to support dust model applications to evaluate the impacts of disturbance processes on local to global-scale wind erosion and dust emissions.

Fugitive Dust Emissions: Development of a Real-time Monitor

DTIC Science & Technology

2011-10-01

the mechanical disturbance of soils which injects particles into the air. Common sources of FD include vehicles driving on unpaved roads...agricultural tilling, and heavy construction operations. For these sources the dust-generation process is caused by two basic physical phenomena...visibility, source apportionment , etc. The PM10 standard set by the U.S. Environmental Protection Agency in 1987 is an example of size-selective

Remote sensing of aerosols by synergy of caliop and modis

NASA Astrophysics Data System (ADS)

Kudo, Rei; Nishizawa, Tomoaki; Higurashi, Akiko; Oikawa, Eiji

2018-04-01

For the monitoring of the global 3-D distribution of aerosol components, we developed the method to retrieve the vertical profiles of water-soluble, light absorbing carbonaceous, dust, and sea salt particles by the synergy of CALIOP and MODIS data. The aerosol product from the synergistic method is expected to be better than the individual products of CALIOP and MODIS. We applied the method to the biomass-burning event in Africa and the dust event in West Asia. The reasonable results were obtained; the much amount of the water-soluble and light absorbing carbonaceous particles were estimated in the biomass-burning event, and the dust particles were estimated in the dust event.

Use of Satellite and Ground-based Digital Images to Detect and Monitor Dust Storms in the Mojave Desert

NASA Astrophysics Data System (ADS)

Chavez, P. S.; MacKinnon, D. J.; Reynolds, R. L.; Velasco, M. G.

2002-12-01

Wind-induced dust emission from sources in the southwestern United States is not a major contributor to global dust flux, but it is important on a regional and national scale because of its effects on air quality, human health and safety, as well as ecosystem dynamics. Integrated remotely sensed satellite, airborne, and ground-based image data have strong potential to detect and monitor active dust storms and map areas vulnerable to wind erosion in the Southwest. Since 1999, high temporal resolution digital images collected by satellite and a ground-based, automated digital camera station have been used to detect, monitor, and analyze the location, size, frequency, duration, and transport patterns of large dust storms in the central Mojave Desert. One of the biggest dust storms of this past decade occurred on April 15, 2002, when at least several million metric tons of dust were emitted from the central Mojave Desert alone. During this storm, geostationary satellite (GOES) images documented the arrival of two very large dust plumes into the Las Vegas Valley, NV, one from a valley about 40 km to the west and the other from a heavily used area about 170 km to the southwest. Large, rapid increases in levels of PM10 (particulate matter less than 10 micrometers) in the Las Vegas area corresponded with the arrival of these plumes, with PM10 values increasing from a range of approximately 100 to 250 micrograms/m3 to 1,100 to 1,500 micrograms/m3 within 30 minutes. Satellite imaging systems currently available cannot detect and monitor dust storms of the size typically generated in the Southwest on an operational basis or be used to produce models for emission-rate predictions. The satellite imaging system on GOES is the only one available having adequate temporal resolution to detect and monitor active dust storms on a routine basis; however, it can only detect very large dust storms because its spatial and spectral resolutions are very low. A satellite imaging system with three to five spectral bands (with adjustable gain settings) and approximately 100 m spatial and 15 to 20 minutes temporal resolutions is needed to effectively monitor southwestern dust storms and events. Such a system would also be useful in other arid regions.

Project 57 Air Monitoring Report: October 1, 2013, through December 31, 2014

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

Mizell, Steve A.; Nikolich, George; McCurdy, Greg

On April 24, 1957, the Atomic Energy Commission (AEC, now the Department of Energy [DOE]) conducted the Project 57 safety experiment in western Emigrant Valley north east of the Nevada National Security Site (NNSS, formerly the Nevada Test Site) on lands withdrawn by the Department of Defense (DoD) for the Nevada Test and Training Range (NTTR). The test was undertaken to develop (1) a means of estimating plutonium distribution resulting from a nonnuclear detonation; (2) biomedical evaluation techniques for use in plutonium-laden environments; (3) methods of surface decontamination; and (4) instruments and field procedures for prompt estimation of alpha contaminationmore » (Shreve, 1958). Although the test did not result in the fission of nuclear materials, it did disseminate plutonium across the land surface. Following the experiment, the AEC fenced the contaminated area and returned control of the surrounding land to the DoD. Various radiological surveys have been performed in the area and in 2007, the DOE expanded the demarked contamination area by posting signs 200 to 400 feet (60 to 120 meters) outside of the original fence. Plutonium in soil is thought to attach preferentially to smaller particles. Therefore, redistribution of soil particulates by wind (dust) is the mechanism most likely to transport plutonium beyond the boundary of the Project 57 contamination area. In 2011, DRI installed two instrumentation towers to measure radiological, meteorological, and dust conditions. The monitoring activity was implemented to determine if radionuclide contamination was detectable in samples of airborne dust and characterize meteorological and environmental parameters that influence dust transport. Collected data also permits comparison of radiological conditions at the Project 57 monitoring stations to conditions observed at Community Environmental Monitoring Program (CEMP) stations around the NTTR. Biweekly samples of airborne particulates are submitted for laboratory assessment of gross alpha and gross beta radioactivity and for determination of gamma-emitting radionuclides. Annual average gross alpha values at the Project 57 monitoring stations are in the same range as the highest two values reported for the CEMP stations surrounding the NTTR. Annual average gross beta values at the Project 57 monitoring stations are slightly higher than the lowest value reported for the CEMP stations surrounding the NTTR. Gamma spectroscopy analyses on samples collected from the Project 57 stations identified only naturally occurring radionuclides. No manmade radionuclides were detected. Thermoluminescent dosimeters (TLDs) indicated that the average annual radioactivity dose at the monitoring stations is higher than the dose determined at surrounding CEMP stations but approximately half of the estimated national average dose received by the general public as a result of exposure to natural sources. The TLDs at the Project 57 monitoring stations are exposed to both natural sources (terrestrial and cosmic) and radioactive releases from the Project 57 contamination area. These comparisons show that the gross alpha, gross beta, and gamma spectroscopy levels at the Project 57 monitoring stations are similar to levels observed at the CEMP stations but that the average annual dose rate is higher than at the CEMP stations. Winds in excess of approximately 15 mph begin to generate dust movement by saltation (migration of sand at the ground surface) or direct suspension in the air. Saltated sand, PM10 (inhalable) dust, and PM2.5 (fine particulate dust) exhibit an approximately exponential increase with increasing wind speed. The greatest concentrations of dust occur for winds exceeding 20 mph. During the reporting period, winds in excess of 20 mph occurred approximately 1.6 percent of the time. Preliminary assessment of individual wind events suggests that dust generation is highly variable likely because of the influence of other meteorological and environmental parameters. Although winds sufficient to generate significant amounts of dust occur at the Project 57 site, they are infrequent and of short duration. Additionally, the potential for wind transport of dust is dependent on other parameters whose influence have not yet been assessed.« less

Ground level and Lidar monitoring of volcanic dust and dust from Patagonia

NASA Astrophysics Data System (ADS)

Otero, L. A.; Losno, R.; Salvador, J. O.; Journet, E.; Qu, Z.; Triquet, S.; Monna, F.; Balkanski, Y.; Bulnes, D.; Ristori, P. R.; Quel, E. J.

2013-05-01

A combined approach including ground level aerosol sampling, lidar and sunphotometer measurements is used to monitor suspended particles in the atmosphere at several sites in Patagonia. Motivated by the Puyehue volcanic eruption in June 2011 two aerosol monitoring stations with several passive and active instruments were installed in Bariloche and Comodoro Rivadavia. The main goal which is to monitor ground lifted and transported ashes and dust involving danger to civil aviation, is achieved by measuring continuously aerosol concentration at ground level and aerosol vertical distribution using lidar. In addition, starting from December 2011, continuous series of weekly accumulated aerosol concentrations at Rio Gallegos are being measured to study the impact of Patagonian dust over the open ocean on phytoplankton primary productivity and CO2 removal. These measurements are going to be coupled with LIDAR monitoring and a dust optical response models to test if aerosol extrapolation can be done from the ground to the top of the layer. Laboratory chemical analysis of the aerosols will include elemental composition, solubilisation kinetic and mineralogical determination. Expected deliverables for this study is the estimation of the amount of dust exported from Patagonia towards the South Atlantic, its chemical properties, including bioavailability simulation, from model and comparison to experimental measurements.

Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites

PubMed Central

Alvarado, Miguel; Gonzalez, Felipe; Fletcher, Andrew; Doshi, Ashray

2015-01-01

Blasting is an integral part of large-scale open cut mining that often occurs in close proximity to population centers and often results in the emission of particulate material and gases potentially hazardous to health. Current air quality monitoring methods rely on limited numbers of fixed sampling locations to validate a complex fluid environment and collect sufficient data to confirm model effectiveness. This paper describes the development of a methodology to address the need of a more precise approach that is capable of characterizing blasting plumes in near-real time. The integration of the system required the modification and integration of an opto-electrical dust sensor, SHARP GP2Y10, into a small fixed-wing and multi-rotor copter, resulting in the collection of data streamed during flight. The paper also describes the calibration of the optical sensor with an industry grade dust-monitoring device, Dusttrak 8520, demonstrating a high correlation between them, with correlation coefficients (R2) greater than 0.9. The laboratory and field tests demonstrate the feasibility of coupling the sensor with the UAVs. However, further work must be done in the areas of sensor selection and calibration as well as flight planning. PMID:26274959

Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites.

PubMed

Alvarado, Miguel; Gonzalez, Felipe; Fletcher, Andrew; Doshi, Ashray

2015-08-12

Blasting is an integral part of large-scale open cut mining that often occurs in close proximity to population centers and often results in the emission of particulate material and gases potentially hazardous to health. Current air quality monitoring methods rely on limited numbers of fixed sampling locations to validate a complex fluid environment and collect sufficient data to confirm model effectiveness. This paper describes the development of a methodology to address the need of a more precise approach that is capable of characterizing blasting plumes in near-real time. The integration of the system required the modification and integration of an opto-electrical dust sensor, SHARP GP2Y10, into a small fixed-wing and multi-rotor copter, resulting in the collection of data streamed during flight. The paper also describes the calibration of the optical sensor with an industry grade dust-monitoring device, Dusttrak 8520, demonstrating a high correlation between them, with correlation coefficients (R(2)) greater than 0.9. The laboratory and field tests demonstrate the feasibility of coupling the sensor with the UAVs. However, further work must be done in the areas of sensor selection and calibration as well as flight planning.

75 FR 69617 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-15

... 1219-AB64 Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust... hearings on the proposed rule addressing Lowering Miners' Exposure to Respirable Coal Mine Dust, Including... miners' exposure to respirable coal mine dust by revising the Agency's existing standards on miners...

76 FR 2617 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-14

... 1219-AB64 Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust... comment period on the proposed rule addressing Lowering Miners' Exposure to Respirable Coal Mine Dust...), MSHA published a proposed rule, Lowering Miners' Exposure to Respirable Coal Mine Dust, Including...

Dust devil signatures in infrasound records of the International Monitoring System

NASA Astrophysics Data System (ADS)

Lorenz, Ralph D.; Christie, Douglas

2015-03-01

We explore whether dust devils have a recognizable signature in infrasound array records, since several Comprehensive Nuclear-Test-Ban Treaty verification stations conducting continuous measurements with microbarometers are in desert areas which see dust devils. The passage of dust devils (and other boundary layer vortices, whether dust laden or not) causes a local temporary drop in pressure: the high-pass time domain filtering in microbarometers results in a "heartbeat" signature, which we observe at the Warramunga station in Australia. We also observe a ~50 min pseudoperiodicity in the occurrence of these signatures and some higher-frequency infrasound. Dust devils do not significantly degrade the treaty verification capability. The pipe arrays for spatial averaging used in infrasound monitoring degrade the detection efficiency of small devils, but the long observation time may allow a useful census of large vortices, and thus, the high-sensitivity infrasonic array data from the monitoring network can be useful in studying columnar vortices in the lower atmosphere.

Applying Dust-on-Snow Research to Colorado Water Management

NASA Astrophysics Data System (ADS)

Landry, C. C.; Painter, T. H.; Barrett, A. P.

2008-12-01

Snowmelt runoff from seasonal snowpacks in Western mountains provides a high proportion of regional water supplies and represents a critical resource subject to complex management imperatives at all levels of local, state, and federal government. Recent research performed in the San Juan Mountains of Southwest Colorado has revealed that deposition of desert dust from the Colorado Plateau onto Colorado mountain snowpacks is playing a hitherto underestimated forcing role in snowmelt timing and intensity. In spring 2006, embedded dust layers forced a 4-5 week advance in complete snowpack ablation at the Senator Beck Basin Study Area, near Red Mountain Pass, and professional water managers throughout Colorado were surprised by an early and compressed snowmelt runoff. Presentations of our preliminary findings during the summer of 2006 at local water district meetings and at a statewide forum resonated with Colorado water managers and resulted in direct stakeholder engagement in the ongoing research program during the subsequent winter. In spring 2007 the research team issued periodic Dust Alerts describing dust-on-snow conditions extant within the study area, as well as anecdotal reports of conditions elsewhere in the state, and discussed the snowmelt ramifications of those dust conditions in the coming 7-15 days, given mid-range NWS weather forecasts. Another round of presentations at district and state-wide stakeholder meetings in summer 2007 resulted in additional districts and agencies engaging in the program and expanding the dust-on-snow monitoring and Dust Alert analysis efforts in spring 2008 to additional sites distributed throughout the state. The original research project is ongoing and the team is now developing a Colorado Dust-on-Snow Program, CODOS, designed to serve all stakeholders in Colorado snowmelt with increasingly intensive monitoring and analysis of snowmelt forcing by dust, and with ongoing research regarding dust-driven mountain snowmelt processes. In this instance, basic science preceded stakeholder engagement and, through active outreach, a consequential, stakeholder-supported program implementing operational application of the research is emerging.

Ensemble classification for identifying neighbourhood sources of fugitive dust and associations with observed PM10

NASA Astrophysics Data System (ADS)

Khuluse-Makhanya, Sibusisiwe; Stein, Alfred; Breytenbach, André; Gxumisa, Athi; Dudeni-Tlhone, Nontembeko; Debba, Pravesh

2017-10-01

In urban areas the deterioration of air quality as a result of fugitive dust receives less attention than the more prominent traffic and industrial emissions. We assessed whether fugitive dust emission sources in the neighbourhood of an air quality monitor are predictors of ambient PM10 concentrations on days characterized by strong local winds. An ensemble maximum likelihood method is developed for land cover mapping in the vicinity of an air quality station using SPOT 6 multi-spectral images. The ensemble maximum likelihood classifier is developed through multiple training iterations for improved accuracy of the bare soil class. Five primary land cover classes are considered, namely built-up areas, vegetation, bare soil, water and 'mixed bare soil' which denotes areas where soil is mixed with either vegetation or synthetic materials. Preliminary validation of the ensemble classifier for the bare soil class results in an accuracy range of 65-98%. Final validation of all classes results in an overall accuracy of 78%. Next, cluster analysis and a varying intercepts regression model are used to assess the statistical association between land cover, a fugitive dust emissions proxy and observed PM10. We found that land cover patterns in the neighbourhood of an air quality station are significant predictors of observed average PM10 concentrations on days when wind speeds are conducive for dust emissions. This study concludes that in the absence of an emissions inventory for ambient particulate matter, PM10 emitted from dust reservoirs can be statistically accounted for by land cover characteristics. This supports the use of land cover data for improved prediction of PM10 at locations without air quality monitoring stations.

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.

Emerging ecological datasets with application for modeling North American dust emissions

NASA Astrophysics Data System (ADS)

McCord, S.; Stauffer, N. G.; Garman, S.; Webb, N.

2017-12-01

In 2011 the US Bureau of Land Management (BLM) established the Assessment, Inventory and Monitoring (AIM) program to monitor the condition of BLM land and to provide data to support evidence-based management of multi-use public lands. The monitoring program shares core data collection methods with the Natural Resources Conservation Service's (NRCS) National Resources Inventory (NRI), implemented on private lands nationally. Combined, the two programs have sampled >30,000 locations since 2003 to provide vegetation composition, vegetation canopy height, the size distribution of inter-canopy gaps, soil texture and crusting information on rangelands and pasture lands across North America. The BLM implements AIM on more than 247.3 million acres of land across the western US, encompassing major dust source regions of the Chihuahuan, Sonoran, Mojave and Great Basin deserts, the Colorado Plateau, and potential high-latitude dust sources in Alaska. The AIM data are publicly available and can be used to support modeling of land surface and boundary-layer processes, including dust emission. While understanding US dust source regions and emission processes has been of national interest since the 1930s Dust Bowl, most attention has been directed to the croplands of the Great Plains and emission hot spots like Owens Lake, California. The magnitude, spatial extent and temporal dynamics of dust emissions from western dust source areas remain highly uncertain. Here, we use ensemble modeling with empirical and physically-based dust emission schemes applied to AIM monitoring data to assess regional-scale patterns of aeolian sediment mass fluxes and dust emissions. The analysis enables connections to be made between dust emission rates at source and other indicators of ecosystem function at the landscape scale. Emerging ecological datasets like AIM provide new opportunities to evaluate aeolian sediment transport responses to land surface conditions, potential interactions with disturbances (e.g., fire) and ecological change (e.g., invasive species), and the impacts of anthropogenic land use and land cover change.

Combined Dust Detection Algorithm by Using MODIS Infrared Channels over East Asia

NASA Technical Reports Server (NTRS)

Park, Sang Seo; Kim, Jhoon; Lee, Jaehwa; Lee, Sukjo; Kim, Jeong Soo; Chang, Lim Seok; Ou, Steve

2014-01-01

A new dust detection algorithm is developed by combining the results of multiple dust detectionmethods using IR channels onboard the MODerate resolution Imaging Spectroradiometer (MODIS). Brightness Temperature Difference (BTD) between two wavelength channels has been used widely in previous dust detection methods. However, BTDmethods have limitations in identifying the offset values of the BTDto discriminate clear-sky areas. The current algorithm overcomes the disadvantages of previous dust detection methods by considering the Brightness Temperature Ratio (BTR) values of the dual wavelength channels with 30-day composite, the optical properties of the dust particles, the variability of surface properties, and the cloud contamination. Therefore, the current algorithm shows improvements in detecting the dust loaded region over land during daytime. Finally, the confidence index of the current dust algorithm is shown in 10 × 10 pixels of the MODIS observations. From January to June, 2006, the results of the current algorithm are within 64 to 81% of those found using the fine mode fraction (FMF) and aerosol index (AI) from the MODIS and Ozone Monitoring Instrument (OMI). The agreement between the results of the current algorithm and the OMI AI over the non-polluted land also ranges from 60 to 67% to avoid errors due to the anthropogenic aerosol. In addition, the developed algorithm shows statistically significant results at four AErosol RObotic NETwork (AERONET) sites in East Asia.

MEDUSA (Martian Environmental DUst Systematic Analyser) for the monitoring of the Martian atmospheric dust and water vapour

NASA Astrophysics Data System (ADS)

Colangeli, L.; Battaglia, R.; della Corte, V.; Esposito, F.; Ferrini, G.; Mazzotta Epifani, E.; Palomba, E.; Palumbo, P.; Panizza, A.; Rotundi, A.

2004-03-01

The knowledge of Martian airborne dust properties and about mechanisms of dust settling/raising to/from the surface are important to determine climate and surface evolution on Mars. Water is an important tracer of climatic changes on long time-scales and is strictly related to the presence of life forms. The study in situ of dust and water vapour properties and evolution in Martian atmosphere is useful to trace back the planet climate, also in function of life form development. This investigation is also appropriate in preparation to future manned exploration of the planet (in relation to hazardous conditions). In this work we discuss the concept of the MEDUSA (Martian Environmental Dust Analyser) experiment that is designed to provide data on grain size and mass distribution, number density, velocity and scattering properties and on water vapour concentration. The instrument is a multisensor system based on optical and impact detection of grains, coupled with cumulative deposition sensors.

Dust emission at Franklin Lake Playa, Mojave Desert (USA): Response to meteorological and hydrologic changes 2005-2008

USGS Publications Warehouse

Reynolds, Richard L.; Bogle, Rian; Vogel, John; Goldstein, Harland L.; Yount, James

2009-01-01

Playa type, size, and setting; playa hydrology; and surface-sediment characteristics are important controls on the type and amount of atmospheric dust emitted from playas. Soft, evaporite-rich sediment develops on the surfaces of some Mojave Desert (USA) playas (wet playas), where the water table is shallow (< 4 m). These areas are sources of atmospheric dust because of continuous or episodic replenishment of wind-erodible salts and disruption of the ground surface during salt formation by evaporation of ground water. Dust emission at Franklin Lake playa was monitored between March 2005 and April 2008. The dust record, based on day-time remote digital camera images captured during high wind, and compared with a nearby precipitation record, shows that aridity suppresses dust emission. High frequency of dust generation appears to be associated with relatively wet periods, identified as either heavy precipitation events or sustained regional precipitation over a few months. Several factors may act separately or in combination to account for this relation. Dust emission may respond rapidly to heavy precipitation when the dissolution of hard, wind-resistant evaporite mineral crusts is followed by the development of soft surfaces with thin, newly formed crusts that are vulnerable to wind erosion and (or) the production of loose aggregates of evaporite minerals that are quickly removed by even moderate winds. Dust loading may also increase when relatively high regional precipitation leads to decreasing depth to the water table, thereby increasing rates of vapor discharge, development of evaporite minerals, and temporary softening of playa surfaces. The seasonality of wind strength was not a major factor in dust-storm frequency at the playa. The lack of major dust emissions related to flood-derived sediment at Franklin Lake playa contrasts with some dry-lake systems elsewhere that may produce large amounts of dust from flood sediments. Flood sediments do not commonly accumulate on the surface of Franklin Lake playa because through-going drainage prevents frequent inundation and deposition of widespread flood sediment.

The footprints of Saharan Air Layer and lightning on the formation of tropical depressions over the eastern Atlantic Ocean

NASA Astrophysics Data System (ADS)

Centeno Delgado, Diana C.

In this study, the results of an observational analysis and a numerical analysis on the role of the Saharan Air Layer during tropical cyclogenesis (TC-genesis) are described. The observational analysis investigates the interaction of dust particles and lightning during the genesis stage of two developed cases (Hurricanes Helene 2006 and Julia 2010). The Weather Research and Forecasting (WRF) and WRF-Chemistry models were used to include and monitor the aerosols and chemical processes that affect TC-genesis. The numerical modeling involved two developed cases (Hurricanes Helene 2006 and Julia 2010) and two non-developed cases (Non-Developed 2011 and Non-Developed 2012). The Aerosol Optical Depth (AOD) and lightning analysis for Hurricane Helene 2006 demonstrated the time-lag connection through their positive contribution to TC-genesis. The observational analyses supported the fact that both systems developed under either strong or weak dust conditions. From the two cases, the location of strong versus weak dust outbreaks in association with lightning was essential interactions that impacted TC-genesis. Furthermore, including dust particles, chemical processes, and aerosol feedback in the simulations with WRF-CHEM provides results closer to observations than regular WRF. The model advantageously shows the location of the dust particles inside of the tropical system. Overall, the results from this study suggest that the SAL is not a determining factor that affects the formation of tropical cyclones.

Surface acoustic wave dust deposition monitor

DOEpatents

Fasching, G.E.; Smith, N.S. Jr.

1988-02-12

A system is disclosed for using the attenuation of surface acoustic waves to monitor real time dust deposition rates on surfaces. The system includes a signal generator, a tone-burst generator/amplifier connected to a transmitting transducer for converting electrical signals into acoustic waves. These waves are transmitted through a path defining means adjacent to a layer of dust and then, in turn, transmitted to a receiving transducer for changing the attenuated acoustic wave to electrical signals. The signals representing the attenuated acoustic waves may be amplified and used in a means for analyzing the output signals to produce an output indicative of the dust deposition rates and/or values of dust in the layer. 8 figs.

Dust exposure during small-scale mining in Tanzania: a pilot study.

PubMed

Bratveit, Magne; Moen, Bente E; Mashalla, Yohana J S; Maalim, Hatua

2003-04-01

Small-scale mining in developing countries is generally labour-intensive and carried out with low levels of mechanization. In the Mererani area in the northern part of Tanzania, there are about 15000 underground miners who are constantly subjected to a poor working environment. Gemstones are found at depths down to 500 m. The objectives of this pilot study were to monitor the exposure to dust during work processes, which are typical of small-scale mining in developing countries, and to make a rough estimation of whether there is a risk of chronic pulmonary diseases for the workers. Personal sampling of respirable dust (n = 15) and 'total' dust (n = 5) was carried out during three consecutive days in one mine, which had a total of 50 workers in two shifts. Sampling started immediately before the miners entered the shaft, and lasted until they reappeared at the mine entrance after 5-8 h. The median crystalline silica content and the combustible content of the respirable dust samples were 14.2 and 5.5%, respectively. When drilling, blasting and shovelling were carried out, the exposure measurements showed high median levels of respirable dust (15.5 mg/m(3)), respirable crystalline silica (2.4 mg/m(3)), respirable combustible dust (1.5 mg/m(3)) and 'total' dust (28.4 mg/m(3)). When only shovelling and loading of sacks took place, the median exposures to respirable dust and respirable crystalline silica were 4.3 and 1.1 mg/m(3). This study shows that the exposure to respirable crystalline silica was high during underground small-scale mining. In the absence of personal protective equipment, the miners in the Mererani area are presumably at a high risk of developing chronic silicosis.

Systematic characterization of structural, dynamical and electrical properties of dust devils and implications for dust lifting processes

NASA Astrophysics Data System (ADS)

Franzese, Gabriele; Esposito, Francesca; Lorenz, Ralph D.; Popa, Ciprian; Silvestro, Simone; Deniskina, Natalia; Cozzolino, Fabio

2017-04-01

Dust devils are convective vortices able to lift sand and dust grains from the soil surface, even in conditions of low wind speed environment. They have been observed not only on Earth but also on other planets of the solar system; in particular, they are largely studied on Mars. Indeed, the contribution of the dust devils to the Martian climate is a highly debated question. In order to investigate this topic, it is important to understand the nature of the dust lifting mechanism by the vortex and characterize the induced electric field. As part of the development process of DREAMS, the meteorological station on board the Schiapparelli lander of the ExoMars 2016 mission, and of the Dust complex package of the ExoMars 2020 mission, we performed various field campaigns in the Sahara desert (Tafilalt region, Morocco). We deployed a fully equipped meteorological station and, during the 2014 summer, we observed three months of dust devils activity, collecting almost six hundreds events. For each dust devil, we monitored the horizontal wind speed and direction, the vertical wind speed, the pressure drop due to the vortex core, the temperature, the induced electric field and the concentration of dust lifted. This data set is unique in literature and represents up to now the most comprehensive one available for the dusty convective vortices. Here we will present the analysis of the Moroccan data with particular emphasis on the study of the atmospheric electric field variations due to the passage of the vortices. The distribution of the vortex parameters (wind speed and direction, pressure, E-field and dust lifted) are showed and compared, when possible, to the ones observed by the Martian surveys. The connection between the E-field and the other parameters will be presented. In the terrestrial environment, the development of the convective vortices is restricted by the presence of the vegetation and of the urban areas, hence dust devils can impact the climate only on local scale. Instead, on Mars the presence of the dust devils has been confirmed at almost every latitude and altitude and it has been indicated as the possible main source of suspended dust outside the storm seasons. Hence, the study of the dust devils becomes of great importance in order to understand the atmospheric dust loading and the global climate of the planet. In addition, the dust lifting phenomena are probably one of the main source of atmospheric electrification on Mars and the measurement and study of the Martian boundary layer electric field is one of the main objectives of the future Martian space missions, such as ExoMars 2020. Indeed, this mission will accommodate "Dust Complex", a suite of sensors that will monitor lifted dust and atmospheric electric field on the surface of Mars. For these reasons, the present work represents a useful tool for the understanding of the dust lifting phenomena and their electrification both on Earth and on Mars.

Detecting and tracking dust outbreaks by using high temporal resolution satellite data

NASA Astrophysics Data System (ADS)

Sannazzaro, Filomena; Marchese, Francesco; Filizzola, Carolina; Tramutoli, Valerio; Pergola, Nicola; Mazzeo, Giuseppe; Paciello, Rossana

2013-04-01

A dust storm is a meteorological phenomenon generated by the action of wind, mainly in arid and semi-arid regions of the planet, particularly at subtropical latitudes. Dust outbreaks, of which frequency increases from year to year concurrently with climate change and reduction of moisture in the soil, may strongly impact on human activity as well as on environment and climate. Efficient early warning systems are then required to monitor them and to mitigate their effects. Satellite remote sensing thanks to a global coverage, to a high frequency of observation and low costs of data represents an important tool for studying and monitoring dust outbreaks. Several techniques have been then proposed to detect and monitor these phenomena from space, analyzing signal in different bands of the electromagnetic spectrum. In particular, methods based on the reverse absorption behaviour of silicate particles in comparison with ice crystals and water droplets, at 11 and 12 micron wavelengths, have been largely employed for detecting dust, although some important issues both in terms of reliability and sensitivity still remain. In this work, an optimized configuration of an innovative algorithm for dust detection, based on the largely accepted Robust Satellite Techniques (RST) multi-temporal approach, is then presented. This optimized algorithm configuration is tested here on Spinning Enhanced Visible and Infrared Imager (SEVIRI) data, analyzing some important dust events affecting Mediterranean basin in recent years. Results of this study, assessed on the basis of independent satellite-based aerosol products, generated by using the Total Ozone Mapping Spectrometer (TOMS), the Ozone Monitoring Instrument (OMI), and the Moderate Resolution Imaging Spectroradiometer (MODIS) data, show that when the spectral resolution of SEVIRI is properly exploited dust and meteorological clouds may be better discriminated. These results encourage further experimentations of the proposed algorithm in view of a possible future implementation in operational monitoring systems.

78 FR 25308 - Proposed Collection; Comment Request; Coal Mine Dust Sampling Devices

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-30

...; Coal Mine Dust Sampling Devices AGENCY: Mine Safety and Health Administration, Labor. ACTION: 60-Day.... Background Continuous Personal Dust Monitors (CPDMs) determine the concentration of respirable dust in coal mines. CPDMs must be designed and constructed for coal miners to wear and operate without impeding their...

Monitoring non-thermal plasma processes for nanoparticle synthesis

NASA Astrophysics Data System (ADS)

Mangolini, Lorenzo

2017-09-01

Process characterization tools have played a crucial role in the investigation of dusty plasmas. The presence of dust in certain non-thermal plasma processes was first detected by laser light scattering measurements. Techniques like laser induced particle explosive evaporation and ion mass spectrometry have provided the experimental evidence necessary for the development of the theory of particle nucleation in silane-containing non-thermal plasmas. This review provides first a summary of these early efforts, and then discusses recent investigations using in situ characterization techniques to understand the interaction between nanoparticles and plasmas. The advancement of such monitoring techniques is necessary to fully develop the potential of non-thermal plasmas as unique materials synthesis and processing platforms. At the same time, the strong coupling between materials and plasma properties suggest that it is also necessary to advance techniques for the measurement of plasma properties while in presence of dust. Recent progress in this area will be discussed.

Lunar Dust and Lunar Simulant Activation and Monitoring

NASA Technical Reports Server (NTRS)

Wallace, W. T.; Hammond, D. K.; Jeevarajan, A. S.

2008-01-01

Prior to returning to the moon, understanding the effects of lunar dust on both human physiology and mechanical equipment is a pressing concern, as problems related to lunar dust during the Apollo missions have been well documented (J.R. Gaier, The Effects of Lunar Dust on EVA Systems During the Apollo Missions. 2005, NASA-Glenn Research Center. p. 65). While efforts were made to remove the dust before reentering the lunar module, via brushing of the suits or vacuuming, a significant amount of dust was returned to the spacecraft, causing various problems. For instance, astronaut Harrison Schmitt complained of hay fever effects caused by the dust, and the abrasive nature of the material was found to cause problems with various joints and seals of the spacecraft and suits. It is clear that, in order to avoid potential health and performance problems while on the lunar surface, the reactive properties of lunar dust must be quenched. It is likely that soil on the lunar surface is in an activated form, i.e. capable of producing oxygen-based radicals in a humidified air environment, due to constant exposure to meteorite impacts, UV radiation, and elements of the solar wind. An activated silica surface serves as a good example. An oxygen-based radical species arises from the breaking of Si-OSi bonds. This system is comparable to that expected for the lunar dust system due to the large amounts of agglutinic glass and silicate vapor deposits present in lunar soil. Unfortunately, exposure to the Earth s atmosphere has passivated the active species on lunar dust, leading to efforts to reactivate the dust in order to understand the true effects that will be experienced by astronauts and equipment on the moon. Electron spin resonance (ESR) spectroscopy is commonly used for the study of radical species, and has been used previously to study silicon- and oxygen-based radicals, as well as the hydroxyl radicals produced by these species in solution (V. Vallyathan, et al., Am. Rev. Respir. Dis. 138 (1988) 1213-1219). The size and cost of these instruments makes them unattractive for the monitoring of lunar dust activity. A more suitable technique is based on the change in fluorescence of a molecule upon reaction with a hydroxyl radical (or other radical species). Fluorescence instruments are much less costly and bulky than ESR spectrometers, and small fluorescence sensors for space missions have already been developed (F. Gao, et al., J. Biomed. Opt. 10 (2005) 054005). For the current fluorescence studies, the terephthalate molecule has been chosen for monitoring the production of hydroxyl radicals in solution. As shown in Scheme 1, the reaction between the non-fluorescent terephthalate molecule and a hydroxyl radical produces the highly-fluorescent 2-hydroxyterephthalate molecule.

Corneal permeability for cement dust: prognosis for occupational safety

NASA Astrophysics Data System (ADS)

Kalmykov, R. V.; Popova, D. V.; Kamenskikh, T. G.; Genina, E. A.; Tuchin, V. V.; Bashkatov, A. N.

2018-02-01

The high dust content in air of a working zone causes prevalence of pathologies of the anterior segment of the eye of workers of cement production. Therefore, studying of features of cement dust impact on structure of a cornea and development of ways of eye protection from this influence is relevant. In this work experimental studies were carried out with twenty eyes of ten rabbits. OCTtomography was used to monitor the light attenuation coefficient of the cornea in vitro during the permeability of cement dust and/or keratoprotector (Systein Ultra). The permeability coefficients of the cornea for water, cement dust and keratoprotector were measured. A computer model allowing one to analyze the diffusion of these substances in the eye cornea was developed. It was shown that 1) the cement dust falling on the eye cornea caused pronounced dehydration of the tissue (thickness decreasing) and led to the increase of the attenuation coefficient, which could affect the deterioration of the eyesight of workers in the conditions of cement production; 2) the application of the keratoprotector to the eye cornea when exposed by cement dust, slowed significantly the dehydration process and did not cause the increase of the attenuation coefficient that characterized the stabilization of visual functions. At this, the keratoprotector itself did not cause dehydration and led to the decrease of the attenuation coefficient, which could allow it to be used for a long time in the order to protect the organ of vision from the negative effects of cement dust.

Evaluation of atmospheric dust prediction models using ground-based observations

NASA Astrophysics Data System (ADS)

Terradellas, Enric; María Baldasano, José; Cuevas, Emilio; Basart, Sara; Huneeus, Nicolás; Camino, Carlos; Dundar, Cinhan; Benincasa, Francesco

2013-04-01

An important step in numerical prediction of mineral dust is the model evaluation aimed to assess its performance to forecast the atmospheric dust content and to lead to new directions in model development and improvement. The first problem to address the evaluation is the scarcity of ground-based routine observations intended for dust monitoring. An alternative option would be the use of satellite products. They have the advantage of a large spatial coverage and a regular availability. However, they do have numerous drawbacks that make the quantitative retrievals of aerosol-related variables difficult and imprecise. This work presents the use of different ground-based observing systems for the evaluation of dust models in the Regional Center for Northern Africa, Middle East and Europe of the World Meteorological Organization (WMO) Sand and Dust Storm Warning Advisory and Assessment System (SDS-WAS). The dust optical depth at 550 nm forecast by different models is regularly compared with the AERONET measurements of Aerosol Optical Depth (AOD) for 40 selected stations. Photometric measurements are a powerful tool for remote sensing of the atmosphere allowing retrieval of aerosol properties, such as AOD. This variable integrates the contribution of different aerosol types, but may be complemented with spectral information that enables hypotheses about the nature of the particles. Comparison is restricted to cases with low Ångström exponent values in order to ensure that coarse mineral dust is the dominant aerosol type. Additionally to column dust load, it is important to evaluate dust surface concentration and dust vertical profiles. Air quality monitoring stations are the main source of data for the evaluation of surface concentration. However they are concentrated in populated and industrialized areas around the Mediterranean. In the present contribution, results of different models are compared with observations of PM10 from the Turkish air quality network for April 2011, when several dust episodes where recorded. In regions devoid of air quality stations (as Saharan and Arabian deserts), model forecasts are regularly evaluated for 38 dust-prone sites through the use of an empirical relationship between visibility data (obtained from meteorological reports) and dust surface concentration. Finally, active remote sensing with lidar or ceilometers is the only way to inquire about the dust vertical distribution. Analysis of selected cases comparing model forecasts and lidar observations at Santa Cruz de Tenerife (Canary Islands) yields promising results regarding the identification of the dust plume thickness. From the results of this pilot trial, the convenience of a regular evaluation will be assessed.

Enhancing weak transient signals in SEVIRI false colour imagery: application to dust source detection in southern Africa

NASA Astrophysics Data System (ADS)

Murray, Jon E.; Brindley, Helen E.; Bryant, Robert G.; Russell, Jacqui E.; Jenkins, Katherine F.

2013-04-01

Understanding the processes governing the availability and entrainment of mineral dust into the atmosphere requires dust sources to be identified and the evolution of dust events to be monitored. To achieve this aim a wide range of approaches have been developed utilising observations from a variety of different satellite sensors. Global maps of source regions and their relative strengths have been derived from instruments in low Earth orbit (e.g. Total Ozone Monitoring Spectrometer (TOMS) (Prospero et al., 2002), MODerate resolution Imaging Spectrometer (MODIS) (Ginoux et al., 2012)). Instruments such as MODIS can also be used to improve precise source location (Baddock et al., 2009) but the information available is restricted to the satellite overpass times which may not be coincident with active dust emission from the source. Hence, at a regional scale, some of the more successful approaches used to characterise the activity of different sources use high temporal resolution data available from instruments in geostationary orbit. For example, the widely used red-green-blue (RGB) dust scheme developed by Lensky and Rosenfeld (2008) (hereafter LR2008) makes use of observations from selected thermal channels of the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) in a false colour rendering scheme in which dust appears pink. This scheme has provided the basis for numerous studies of north African dust sources and factors governing their activation (e.g. Schepanski et al., 2007, 2009, 2012). However, the LR2008 imagery can fail to identify dust events due to the effects of atmospheric moisture, variations in dust layer height and optical properties, and surface conditions (Brindley et al., 2012). Here we introduce a new method designed to circumvent some of these issues and enhance the signature of dust events using observations from SEVIRI. The approach involves the derivation of a composite clear-sky signal for selected channels on an individual time-step and pixel basis. These composite signals are subtracted from each observation in the relevant channels to enhance weak transient signals associated with low levels of dust emission. Different channel combinations are then rendered in false colour imagery to better identify dust source locations and activity. We have applied this new clear-sky difference (CSD) algorithm over three key source regions in southern Africa: the Makgadikgadi Basin, Etosha Pan, and the Namibian and western South African coast. Case studies indicate that advantages associated with the CSD approach include an improved ability to detect dust and distinguish multiple sources, the observation of source activation earlier in the diurnal cycle, and an improved ability to pinpoint dust source locations. These advantages are confirmed by a survey of four-years of data, comparing the results obtained using the CSD technique with those derived from LR2008 dust imagery. On average the new algorithm more than doubles the number of dust events identified, with the greatest improvement for the Makgadigkadi Basin and coastal regions. We anticipate exploiting this new activation record derived using the CSD approach to better understand the surface and meteorological conditions controlling dust uplift and subsequent atmospheric transport.

Martian Dust Cycle

NASA Astrophysics Data System (ADS)

Cantor, B. A.; James, P. B.

The Mars Observer Camera (MOC), aboard Mars Global Surveyor (MGS), has completed approximately 3 consecutive Martian years of global monitoring, since entering its mapping orbit on March 9, 1999. MOC observations have shown the important role that dust devils and dust storms play in the Martian dust cycle on time scales ranging from semi-diurnally to interannually. These dust events have been observed across much of the planet from the depths of Hellas basin to the summit of Arsia Mons and range in size from10s of meters across (dust devils) to planet encircling (global dust veils). Though dust devils occur throughout most of the Martian year, each hemisphere has a "dust devil season" that generally follows the subsolar latitude and appears to be repeatable from year-to-year. An exception is NW Amazonis, which has frequent, large dust devils throughout northern spring and summer. MOC observations show no evidence that dust devils cause or lead to dust storms, however, observations do suggest that dust storms can initiate dust devil activity. Dust devils also might play a role in maintaining the low background dust opacity of the Martian atmosphere. Dust storms occur almost daily with few exceptions, with 1000s occurring each year in the present Martian environment, dispelling the notion of a "Classical Dust Storm Season". However, there does appear to be an annual dust storm cycle, with storms developing in specific locations during certain seasons and that some individual storm events are repeatable from year-to-year. The majority of storms develop near the receding seasonal polar cap edge or along the corresponding polar hood boundaries in their respective hemispheres, but they also occur in the northern plains, the windward side of the large shield volcanoes, and in low laying regions such as Hellas, Argyre, and Chryse. The rarest of dust events are the "Great Storms" or "Global Events", of which only 6 (4 "planet encircling" and 2 "global") have been observed to date. With MOC we have observed that global dust events are not individual storms but are composed of a number of local and regional storms (sources) and that they do not signify climatic changes, but are only short-term perturbations to the general interannually repeatable Martian dust storm cycle.

Lunar Dust and Lunar Simulant Activation, Monitoring, Solution and Cellular Toxicity Properties

NASA Technical Reports Server (NTRS)

Wallace, William; Jeevarajan, A. S.

2009-01-01

During the Apollo missions, many undesirable situations were encountered that must be mitigated prior to returning humans to the moon. Lunar dust (that part of the lunar regolith less than 20 microns in diameter) was found to produce several problems with mechanical equipment and could have conceivably produced harmful physiological effects for the astronauts. For instance, the abrasive nature of the dust was found to cause malfunctions of various joints and seals of the spacecraft and suits. Additionally, though efforts were made to exclude lunar dust from the cabin of the lunar module, a significant amount of material nonetheless found its way inside. With the loss of gravity correlated with ascent from the lunar surface, much of the finer fraction of this dust began to float and was inhaled by the astronauts. The short visits tothe Moon during Apollo lessened exposure to the dust, but the plan for future lunar stays of up to six months demands that methods be developed to minimize the risk of dust inhalation. The guidelines for what constitutes "safe" exposure will guide the development of engineering controls aimed at preventing the presence of dust in the lunar habitat. This work has shown the effects of grinding on the activation level of lunar dust, the changes in dissolution properties of lunar simulant, and the production of cytokines by cellular systems. Grinding of lunar dust leads to the production of radicals in solution and increased dissolution of lunar simulant in buffers of different pH. Additionally, ground lunar simulant has been shown to promote the production of IL-6 and IL-8, pro-inflammatory cytokines, by alveolar epithelial cells. These results provide evidence of the need for further studies on these materials prior to returning to the lunar surface.

Instrument study of the Lunar Dust eXplorer (LDX) for a lunar lander mission

NASA Astrophysics Data System (ADS)

Li, Yanwei; Srama, Ralf; Henkel, Hartmut; Sternovsky, Zoltan; Kempf, Sascha; Wu, Yiyong; Grün, Eberhard

2014-11-01

One of the highest-priority issues for a future human or robotic lunar exploration is the lunar dust. This problem should be studied in depth in order to develop an environment model for a future lunar exploration. A future ESA lunar lander mission requires the measurement of dust transport phenomena above the lunar surface. Here, we describe an instrument design concept to measure slow and fast moving charged lunar dust which is based on the principle of charge induction. LDX has a low mass and measures the speed and trajectory of individual dust particles with sizes below one micrometer. Furthermore, LDX has an impact ionization target to monitor the interplanetary dust background. The sensor consists of three planes of segmented grid electrodes and each electrode is connected to an individual charge sensitive amplifier. Numerical signals were computed using the Coulomb software package. The LDX sensitive area is approximately 400 cm2. Our simulations reveal trajectory uncertainties of better than 2° with an absolute position accuracy of better than 2 mm.

The effects of transported Asian dust on the composition and concentration of ambient fungi in Taiwan

NASA Astrophysics Data System (ADS)

Chao, H. Jasmine; Chan, Chang-Chuan; Rao, Carol Y.; Lee, Chung-Te; Chuang, Ying-Chih; Chiu, Yueh-Hsiu; Hsu, Hsiao-Hsien; Wu, Yi-Hua

2012-03-01

This study was conducted to evaluate the effects of transported Asian dust and other environmental parameters on the levels and compositions of ambient fungi in the atmosphere of northern Taiwan. We monitored Asian dust events in Taipei County, Taiwan from January 2003 to June 2004. We used duplicate Burkard portable air samplers to collect ambient fungi before, during, and after dust events. Six transported Asian dust events were monitored during the study period. Elevated concentrations of Aspergillus ( A. niger, specifically), Coelomycetes, Rhinocladiella, Sporothrix and Verticillium were noted ( p < 0.05) during Asian dust periods. Botryosporium and Trichothecium were only recovered during dust event days. Multiple regression analysis showed that fungal levels were positively associated with temperature, wind speed, rainfall, non-methane hydrocarbons and particulates with aerodynamic diameters ≤10 μm (PM10), and negatively correlated with relative humidity and ozone. Our results demonstrated that Asian dust events affected ambient fungal concentrations and compositions in northern Taiwan. Ambient fungi also had complex dynamics with air pollutants and meteorological factors. Future studies should explore the health impacts of ambient fungi during Asian dust events, adjusting for the synergistic/antagonistic effects of weather and air pollutants.

An automatic collector to monitor insoluble atmospheric deposition: application for mineral dust deposition

NASA Astrophysics Data System (ADS)

Laurent, B.; Losno, R.; Chevaillier, S.; Vincent, J.; Roullet, P.; Bon Nguyen, E.; Ouboulmane, N.; Triquet, S.; Fornier, M.; Raimbault, P.; Bergametti, G.

2015-07-01

Deposition is one of the key terms of the mineral dust cycle. However, dust deposition remains poorly constrained in transport models simulating the atmospheric dust cycle. This is mainly due to the limited number of relevant deposition measurements. This paper aims to present an automatic collector (CARAGA), specially developed to sample the total (dry and wet) atmospheric deposition of insoluble dust in remote areas. The autonomy of the CARAGA can range from 25 days to almost 1 year depending on the programmed sampling frequency (from 1 day to 2 weeks respectively). This collector is used to sample atmospheric deposition of Saharan dust on the Frioul islands in the Gulf of Lions in the Western Mediterranean. To quantify the mineral dust mass in deposition samples, a weighing and ignition protocol is applied. Almost 2 years of continuous deposition measurements performed on a weekly sampling basis on Frioul Island are presented and discussed with air mass trajectories and satellite observations of dust. Insoluble mineral deposition measured on Frioul Island was 2.45 g m-2 for February to December 2011 and 3.16 g m-2 for January to October 2012. Nine major mineral deposition events, measured during periods with significant MODIS aerosol optical depths, were associated with air masses coming from the southern Mediterranean Basin and North Africa.

Dust-Tolerant Intelligent Electrical Connection System

NASA Technical Reports Server (NTRS)

Lewis, Mark; Dokos, Adam; Perotti, Jose; Calle, Carlos; Mueller, Robert; Bastin, Gary; Carlson, Jeffrey; Townsend, Ivan, III; Immer, Chirstopher; Medelius, Pedro

2012-01-01

Faults in wiring systems are a serious concern for the aerospace and aeronautic (commercial, military, and civilian) industries. Circuit failures and vehicle accidents have occurred and have been attributed to faulty wiring created by open and/or short circuits. Often, such circuit failures occur due to vibration during vehicle launch or operation. Therefore, developing non-intrusive fault-tolerant techniques is necessary to detect circuit faults and automatically route signals through alternate recovery paths while the vehicle or lunar surface systems equipment is in operation. Electrical connector concepts combining dust mitigation strategies and cable diagnostic technologies have significant application for lunar and Martian surface systems, as well as for dusty terrestrial applications. The dust-tolerant intelligent electrical connection system has several novel concepts and unique features. It combines intelligent cable diagnostics (health monitoring) and automatic circuit routing capabilities into a dust-tolerant electrical umbilical. It retrofits a clamshell protective dust cover to an existing connector for reduced gravity operation, and features a universal connector housing with three styles of dust protection: inverted cap, rotating cap, and clamshell. It uses a self-healing membrane as a dust barrier for electrical connectors where required, while also combining lotus leaf technology for applications where a dust-resistant coating providing low surface tension is needed to mitigate Van der Waals forces, thereby disallowing dust particle adhesion to connector surfaces. It also permits using a ruggedized iris mechanism with an embedded electrodynamic dust shield as a dust barrier for electrical connectors where required.

Understanding the Activation and Solution Properties of Lunar Dust for Future Lunar Habitation

NASA Technical Reports Server (NTRS)

Wallace, William T.; Jeevarajan, Antony S.

2009-01-01

The decision to return humans to the moon by 2020 makes it imperative to understand the effects of lunar dust on human and mechanical systems.( Bush 2004; Gaier 2005; Mendell 2005) During the Apollo missions, dust was found to cause numerous problems for various instruments and systems. Additionally, the dust may have caused health issues for some of the astronauts.(Gaier 2005; Rowe 2007) It is necessary, therefore, for studies to be carried out in a variety of disciplines in order to mitigate the effects of the dust as completely as possible. Due to the lack of an atmosphere, there is nothing to protect the lunar soil from ultraviolet radiation, solar wind, and meteorite impacts. These processes could all serve to "activate" the soil, or produce reactive surface species. In order to understand the possible toxic effects of the reactive dust, it is necessary to "reactivate" the dust, as samples returned during the Apollo missions were exposed to the atmosphere of the Earth. We have used grinding and exposure to UV radiation in order to mimic some of the processes occurring on the lunar surface. To monitor the reactivity of the dust, we have measured the ability of the dust to produce hydroxyl radicals in solution. These radicals have been measured using a novel fluorescent technique developed in our laboratory,(Wallace et al. 2008) as well as using electron paramagnetic resonance (EPR).

Morphology and Dynamics of Jets of Comet 67P Churyumov-Gerasimenko: Early Phase Development

NASA Astrophysics Data System (ADS)

Lin, Zhong-Yi; Ip, Wing-Huen; Lai, Ian-Lin; Lee, Jui-Chi; Pajola, Maurizio; Lara, Luisa; Gutierrez, Pedro; Rodrigo, Rafael; Bodewits, Dennis; A'Hearn, Mike; Vincent, Jean-Baptiste; Agarwal, Jessica; Keller, Uwe; Mottola, Stefano; Bertini, Ivano; Lowry, Stephen; Rozek, Agata; Liao, Ying; Rosetta Osiris Coi Team

2015-04-01

The scientific camera, OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System), onboard the Rosetta spacecraft comprises a Narrow Angle Camera (NAC) for nucleus surface and dust studies and a Wide Angle Camera (WAC) for the wide field of dust and gas coma investigations. The dynamical behavior of jets in the dust coma continuously monitored by using dust filters from the arrival at the comet (August 2014) throughout the mapping phase (Oct. 2014) is described here. The analysis will cover the study of the time variability of jets, the source regions of these jets, the excess brightness of jets relative to the averaged coma brightness, and the brightness distribution of dust jets along the projected distance. The jets detected between August and September originated mostly from the neck region (Hapi). Morphological changes appeared over a time scale of several days in September. The brightness slope of the dust jets is much steeper than the background coma. This might be related to the sublimation or fragmentation of the emitted dust grains. Inter-comparison with results from other experiments will be necessary to understand the difference between the dust emitted from Hapi and those from the head and the body of the nucleus surface. The physical properties of the Hapi jets will be compared to dust jets (and their source regions) to emerge as comet 67P moves around the perihelion.

A parameterization of dust emission (PM10) fluxes of dust events observed at Naiman in Inner Mongolia using the monitored tower data

NASA Astrophysics Data System (ADS)

Park, Soon-Ung; Ju, Jae-Won; Lee, In-Hye; Joo, Seung Jin

2016-09-01

The optimal regression equations for the dust emission flux parameterized with the friction velocity (u*) only, the friction velocity with the threshold friction velocity (u*t) and the friction velocity together with the flux Richardson number (Rf) in the dust source region are derived using the sonic anemometer measured momentum and kinematic heat fluxes at 8 m height and the two-level (3 m and 15 m height) measured PM10 concentrations from a 20-m monitoring tower located at Naiman in the Asian dust source region in China for the period from March 2013 to November 2014. The analysis period is divided into three sub-periods based on the Normalized Difference Vegetation Index (NDVI) to eliminate the effect of vegetation on the dust emission flux. The dust event is identified as a peak half hourly mean dust concentration (PM10) at 3 m height exceeding the sub-period mean dust concentration plus one standard deviation of the sub-period. The total of 317 dust events is identified with the highest number of dust event of 18.8 times a month in summer. The optimal regression equations of the dust emission flux (Fc) for dust events parameterized with u* and Rf are found to simulate quite well the dust emission flux estimated by the observed data at the site for all periods especially for the unstable stratification, suggesting the potential usefulness of these equations parameterized by u* with Rf rather than those by u* only and u* together with u*t for the estimation of the dust emission flux in the Asian dust source region.

The return periods and risk assessment of severe dust storms in Inner Mongolia with consideration of the main contributing factors.

PubMed

Liu, Xueqin; Li, Ning; Xie, Wei; Wu, Jidong; Zhang, Peng; Ji, Zhonghui

2012-09-01

This study presents a methodology for return period analysis and risk assessment of severe dust storm disaster. Meteorological observation data, soil moisture data, and remote sensing data from 30 meteorological stations in Inner Mongolia (western China) from 1985 to 2006 were used for the study. A composite index of severe dust storm disaster (Index I (SDS)) based on the influence mechanisms of the main contributing factors was developed by using the analytic hierarchy process and the weighted comprehensive method, and the hazard risk curves (i.e., the transcendental probability curves of I (SDS)) for the 30 stations were established using the parameter estimation method. We then analyzed the risk of the occurrence of severe dust storm under different scenarios of 5-, 10-, 20-, and 50-year return periods. The results show that the risk decreased from west to east across Inner Mongolia, and there are four severe dust storm occurrence peak value centers, including Guaizihu, Jilantai, Hailisu, and Zhurihe-Erenhot. The severity of dust storms in seven places will be intolerable in the 50-year return period scenario and in three places in the 20-year return period scenario. These results indicate that these locations should concentrate forces on disaster prevention, monitoring, and early warning. The I (SDS) was developed as an easily understandable tool useful for the assessment and comparison of the relative risk of severe dust storm disasters in different areas. The risk assessment was specifically intended to support local and national government agencies in their management of severe dust storm disasters in their efforts to (1) make resource allocation decisions, (2) make high-level planning decisions, and (3) raise public awareness of severe dust storm risk.

Proceedings from the Workshop on Research Needs for Assessment and Management of Non-Point Air Emissions from Department of Defense Activities held in Research Triangle Park, North Carolina on 19-21 February 2008

DTIC Science & Technology

2008-10-01

Chow, J.C. (2006). Feasibility of soil dust source apportionment by the pyrolysis-gas chromatography/mass spectrometry method. J. Air Waste Manage...receptor-oriented source apportionment models. • Develop monitoring methods to determine source and fence line amounts of fugitive dust emissions for...offsite impact, including evaluation with receptor- oriented source apportionment models 76 8.8.1 Background 76 8.8.2 Significance 77 8.8.3

The Electric Environment of Martian Dust Devils

NASA Astrophysics Data System (ADS)

Barth, E. L.; Farrell, W. M.; Rafkin, S. C.

2017-12-01

While Martian dust devils have been monitored through decades of observations, we have yet to study their possible electrical effects from in situ instrumentation. However, evidence for the existence of active electrodynamic processes on Mars is provided by laboratory studies of analog material and field campaigns of dust devils on Earth. We have enabled our Mars regional scale atmospheric model (MRAMS) to estimate an upper limit on electric fields generated through dust devil circulations by including charged particles as defined from the Macroscopic Triboelectric Simulation (MTS) code. MRAMS is used to investigate the complex physics of regional, mesoscale, and microscale atmospheric phenomena on Mars; it is a 3-D, nonhydrostatic model, which permits the simulation of atmospheric flows with large vertical accelerations, such as dust devils. MTS is a 3-D particle code which quantifies charging associated with swirling, mixing dust grains; grains of pre-defined sizes and compositions are placed in a simulation box and allowed to move under the influence of winds and gravity. Our MRAMS grid cell size makes our results most applicable to dust devils of a few hundred meters in diameter. We have run a number of simulations to understand the sensitivity of the electric field strength to the particle size and abundance and the amount of charge on each dust grain. We find that Efields can indeed develop in Martian dust convective features via dust grain filtration effects. The overall value of these E-fields is strongly dependent upon dust grain size, dust load, and lifting efficiency, and field strengths can range from 100s of mV/m to 10s of kV/m.

Mars Spark Source Prototype Developed

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.; Lindamood, Glenn R.; VanderWal, Randall L.; Weiland, Karen J.

2000-01-01

The Mars Spark Source Prototype (MSSP) hardware was developed as part of a proof of concept system for the detection of trace metals such as lead, cadmium, and arsenic in Martian dusts and soils. A spark discharge produces plasma from a soil sample, and detectors measure the optical emission from metals in the plasma to identify and quantify them. Trace metal measurements are vital in assessing whether or not the Martian environment will be toxic to human explorers. The current method of x-ray fluorescence can yield concentrations of major species only. Other instruments are incompatible with the volume, weight, and power constraints for a Mars mission. The new instrument will be developed primarily for use in the Martian environment, but it would be adaptable for terrestrial use in environmental monitoring. The NASA Glenn Research Center at Lewis Field initiated the development of the MSSP as part of Glenn's Director's Discretionary Fund project for the Spark Analysis Detection of Trace Metal Species in Martian Dusts and Soils. The objective of this project is to develop and demonstrate a compact, sensitive optical instrument for the detection of trace hazardous metals in Martian dusts and soils.

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.

A new approach to developing a fugitive road dust emission inventory and emission trend from 2006 to 2010 in the beijing metropolitan area, china.

PubMed

Fan, Shoubin; Tian, Gang; Cheng, Shuiyuan; Qin, Jianping

2013-07-01

The USEPA emission factor (AP-42) of fugitive road dust (FRD) is widely used in establishing emission inventories. However, road silt loading sampling for AP-42 is expensive, time consuming, and dangerous. Therefore, a new method for establishing emission inventories based on road dust-fall (DF) monitors is described. Between January 2006 and December 2010, DF was monitored at 40 sites (80 samples), and background dust fall (DF) was monitored at 14 sites in the Beijing metropolitan area. Also during this period, 58 samples of road silt loadings were taken and used in the AP-42 emission factor equation to calculate FRD with particulate matter ≤10 μm in diameter [FRD(PM)] emission from the roads. Simultaneous measurement of FRD(PM) emissions calculated by AP-42 and ΔDF (i.e., the difference between the DF and DF) measured using gauges showed that the FRD(PM) emission for road dust was proportional to the ΔDF ( = 0.92). The FRD(PM) emission (kg km × 30 d) was calculated using the monitored ΔDF (t km × 30 d) by the formulation FRD(PM) = 278.3 × ΔDF - 1151.2. The ΔDF showed a general decline from 2006 to 2010. In particular, there was a sharp decline in August, September, and October 2008 due to strict dust controls enforced during the 2008 Olympic Games. Although there was a small increase in ΔDF after the Games, by the end of 2010 values were still lower than those before the Games. Using the 2006 ΔDF value as a benchmark, ΔDF values declined by 24.7, 33.0, 38.3, and 31.4% in 2007, 2008, 2009, and 2010, respectively. Based on using AP-42 calculations from silt loading and traffic information in 2007, the FRD(PM) emission distribution in the Beijing metropolitan area was mapped, and there were 2.05 × 10 tons of FRD(PM) emitted in 2007. The FRD(PM) from 2006 to 2010 was calculated by the ΔDF values. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Development of Mercury dust monitor (MDM) using piezo-electric sensor on boad BepiColombo spacecraft

NASA Astrophysics Data System (ADS)

Nogami, K.; Mercury Dust Team

BepiColombo spacecraft K.Nogami(1), S.Sasaki(2), T.Miyachi(3), H.Ohashi(4), M.Fujii(5), H.Shibata(6), T.Iwai(7), A.Fujiwara(8), H.Yano(8), S.Minami(9), S.Takechi(9), T.Ohnishi(9), R.Srama(10) and E.Grün(10) (1) Dokkyo Medical Univ., Japan, (2) National Astronomical Observatory of Japan, Japan, (3) Waseda Univ., Japan, (4) Tokyo Univ. Marine Science and Technology, Japan, (5) FAM Science Co. Ltd., Japan, (6) Kyoto Univ., Japan, (7) Univ. of Tokyo, Japan, (8) ISAS, JAXA, Japan, (9) Osaka City University, Japan, (10) Max Planck Institute for Nuclear Physics, Germany (nogami@dokkyomed.ac.jp / +81-282-87-2116 ) BepiColombo" project is the first large-sized Europe-Japan joint mission to provide the best understanding of Mercury to date. It consists of two individual orbiters: the Mercury Planetary Orbiter (MPO), that will map the planet, and the Mercury Magnetospheric Orbiter (MMO), that will investigate its magnetosphere. It will be launched in 2013. We will have a chance to put the dust monitor (MDM) on the MMO. This project is intended to reveal the dust environment near Mercury. The scientific interests are to investigate the flux and the variations of interplanetary meteoroid complex inside 1 AU. The Mercury dust monitor is a light-weight, heat resistant (˜300°C) piezoelectric ceramic (PZT) which will be installed on the side panel of the BepiColombo MMO spacecraft. Solar radiation near Mercury is ten times greater than near Earth, but the PZT sensor will endure this severe condition. The momentum, crude incoming direction and impact velocity of the cosmic dusts, with masses > 10-15 g are derived from the impact signal from the monitor. This dust monitor is composed of 4 flat PZT plate, 5cm x 5cm and 1mm thick each, and total sensitive area is almost 100 cm2 . The impact signals are processed by a digital circuit with about several 10 MHz A/D converters. From the rise time of the signals, we can know rough speed of the impact particles and also can separate the real impact signals from the noises. The weight of this PZT monitor is about 0.2 kg, and the weight of this circuit, include box and connector is about 0.4 kg and nominal power is less than 3W. Total weight of MDM system will be less than 0.6 kg. The calibration experiments of this system are made using Van de Graaff microparticle accelerators at HIT, Univ. of Tokyo in Japan ( silver or carbon particles, max speed ˜ 10 km/s ), and at MPI-K in Germany ( carbon, iron and silver particles, max speed ˜ 70 km/s ).

75 FR 64411 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-19

...The Mine Safety and Health Administration (MSHA) proposes to lower miners' exposure to respirable coal mine dust by revising the Agency's existing standards on miners' occupational exposure to respirable coal mine dust. The major provisions of the proposal would lower the existing exposure limit; provide for full-shift sampling; redefine the term ``normal production shift; '' and add reexamination and decertification requirements for persons certified to sample, and maintain and calibrate sampling devices. In addition, the proposed rule would provide for single shift compliance sampling under the mine operator and MSHA's inspector sampling programs, and would establish sampling requirements for use of the Continuous Personal Dust Monitor (CPDM) and expanded requirements for medical surveillance. The proposed rule would significantly improve health protections for this Nation's coal miners by reducing their occupational exposure to respirable coal mine dust and lowering the risk that they will suffer material impairment of health or functional capacity over their working lives.

Jovian dust streams: A monitor of Io's volcanic plume activity

USGS Publications Warehouse

Kruger, H.; Geissler, P.; Horanyi, M.; Graps, A.L.; Kempf, S.; Srama, R.; Moragas-Klostermeyer, G.; Moissl, R.; Johnson, T.V.; Grun, E.

2003-01-01

Streams of high speed dust particles originate from Jupiter's moon Io. After release from Io, the particles collect electric charges in the Io plasma torus, gain energy from the co-rotating electric field of Jupiter's magnetosphere, and leave the Jovian system into interplanetary space with escape speeds over 200 km s-1. The Galileo spacecraft has continuously monitored the dust streams during 34 revolutions about Jupiter between 1996 and 2002. The observed dust fluxes exhibit large orbit-to-orbit variability due to systematic and stochastic changes. After removal of the systematic variations, the total dust emission rate of Io has been calculated. It varies between 10-3 and 10 kg s-1, and is typically in the range of 0.1 to 1 kg s-1. We compare the dust emission rate with other markers of volcanic activity on Io like large-area surface changes caused by volcanic deposits and sightings of volcanic plumes. Copyright 2003 by the American Geophysical Union.

In situ observations of dust particles in Martian dust belts using a large-sensitive-area dust sensor

NASA Astrophysics Data System (ADS)

Kobayashi, Masanori; Krüger, Harald; Senshu, Hiroki; Wada, Koji; Okudaira, Osamu; Sasaki, Sho; Kimura, Hiroshi

2018-07-01

In order to determine whether Martian dust belts (ring or torus) actually exist and, if so, to determine the characteristics of the dust, we propose a Circum-Martian Dust Monitor (CMDM) to be deployed on the Martian Moons Exploration (MMX) project, in which JAXA plans to launch the spacecraft in 2024, investigate Phobos and Deimos, and return samples back to Earth. The CMDM is a newly developed instrument that is an impact dust detector. It weighs only 650 g and has a sensor aperture area of ∼1 m2, according to the conceptual design study. Detectable velocities (v) range from 0.5 km/s to more than 70 km/s, which will cover all possible dust particles: circummartian (low v), interplanetary (mid v), and interstellar (high v) particles. The measurable mass ranges from 1.3 × 10-9 g to 7.8 × 10-7 g at v = 0.5 km/s. Since the MMX spacecraft will take a quasi-circular, prograde orbit around Mars, the CMDM will be able to investigate particles from Phobos and Deimos with relative velocities lower than 1 km/s. Therefore, the CMDM will be able to determine whether or not a confined dust ring exists along Phobos' orbit and whether an extended dust torus exists along Deimos' orbit. It may also be able to clarify whether or not any such ring or torus are self-sustained.

An evaluation of the GCA respirable dust monitor 101-1.

PubMed

Marple, V A; Rubow, K L

1978-01-01

The GCA RDM 101-1 has been evaluated using aerosols of coal, Arizona road dust, silica, potash, and rock (copper ore) particles. The effects of the dust mass concentration, particle size distribution, and dust material on the instrument response were investigated. The instrument was found to measure the mass concentrations of respirable dust aerosols up to about 16 mg/m3 for coal and rock dust and about 20 mg/m3 for silica, potash, and Arizona road dust, providing there is not appreciable mass in the size range below approximateley 0.7 micrometer aerodynamic diameter.

The summer 2012 Saharan dust season in the western Mediterranean with focus on the intense event of late June during the Pre-ChArMEx campaign

NASA Astrophysics Data System (ADS)

Dulac, François; Nicolas, José B.; Sciare, Jean; Mallet, Marc; Léon, Jean-François; Pont, Véronique; Sicard, Michaël; Renard, Jean-Baptiste; Nabat, Pierre; El Amraoui, Laaziz; Jaumouillé, Elodie; Roberts, Greg; Attié, Jean-Luc; Somot, Samuel; Laurent, Benoît; Losno, Rémi; Vincent, Julie; Formenti, Paola; Bergametti, Gilles; Ravetta, François

2013-04-01

Saharan dust is an usual aerosol over the Mediterranean basin that contributes to the high average aerosol load during summer in the western Mediterranean marine environment. Satellite monitoring shows that dust events were numerous during summer 2012. Even though most of the transport of dust particles occurs in altitude, as shown by surface lidars and airborne data, dust events significantly impact surface PM10 concentrations even in urban traffic type of air quality monitoring stations, and background stations are needed to assess the contribution of desert dust. During the pre-ChArMEx field campaign and associated field campaigns TRAQA and VESSAER in the north-western Mediterranean, a large scale African dust event occurred in late June-early July with optical depth levels in the visible up to 0.5-0.7 rather unusual in that area according to long time remote sensing AERONET or satellite series. We have performed measurements in the dust plume for several days with a particularly large variety of both ground-based and airborne (from sounding balloons, an aircraft and an ultra-light aircraft) remote sensing and in situ instruments. In addition to satellite aerosol products including MSG/SEVIRI, which provides the spatial distribution of the aerosol optical depth over the basin up to 4 times per hour, POLDER and CALIOP, this yields a complete set of unusual quantitative constraints for model simulations of this event, combining data on aerosol optical depth, vertical distribution, particle size distribution, chemical, optical and microphysical properties. We shall provide an overview of the data set that includes original measurements of the vertical profile of the aerosol size distribution with a new small balloon borne OPC called LOAC (Light Optical Aerosol Counter) showing large dust particles (up to 30 µm in diameter) within a thick dust layer between 1 and 5 km above south-eastern France, and original network measurement of weekly dust deposition with a new autonomous deposition sampler called CARAGA (Collecteur Automatique de Retombées Atmosphériques à Grande Autonomie). We shall also present preliminary comparisons of observations with a set of 3D RCM and transport model simulations of dust transport with ALADIN, Meso NH, RegCM, CHIMERE and MOCAGE, and first estimates of the regional and local dust direct SW and LW radiative forcing. Acknowledgements are addressed to CNES for balloon operation, to SAFIRE for ATR42 aircraft operation, to ICARE for satellite products, and to OMP/SEDOO for the ChArMEx data portal. LOAC development has been funded by ANR and CARAGA development by UDDP7. The main sponsors of the campaign were ADEME and INSU for Pre-ChArMEx/TRAQA and EUFAR for VESSAER. Authors are also especially grateful to a long list of scientists who provided technical assistance in this work and to CORSiCA project coordination, INRA and Qualitair Corse for logistic support.

The Fogging Method with Variable of Nozle Diameter as the Mitigation Alternative for Spreading the Dust of Cement

NASA Astrophysics Data System (ADS)

Purwanta, J.; Marnoto, T.; Setyono, P.; Ramelan, A. H.

2018-03-01

The cement plant impacts on the lives of people around the factory site, one of them on the air quality, especially dust. Cement plant has made various efforts to mitigate dust generated, but the reality on the ground is still a lot of dust flying around either of the cement factory chimneys and transportation. The purpose of this study was to find the optimum condition of nozle diameter from the cement dust catcher, for mitigation the dust spread to around the cement plant. This study uses research methods such as collecting secondary data which includes data intensity rainfall, the average long rains, wind speed and direction as well as data quality monitoring dust around PT. Semen Gresik (Persero) Tbk. Tuban plant. To determine the wind direction propensity models, use a soft Windrose file. To determine the impact on the spread of dust into the environment using secondary data monitoring air quality. Results of the study is that the mitigation of dust around the cement plant is influenced by natural factors, namely the tendency of wind direction, rainfall and rainy days, and the rate of dust emission from the chimney. I try for operate the cement dust catcher with variable of nozle diameter. Finally, I find the optimum condition of nozle diameter for cement dust catcher is 1.40 mm, with line equation is y = 149.09.e 1.6237.x and error 5%. In that condition, nozle can make the fog with a good quality and it can catch the cement dust well.

The Fox Guarding the Chicken Coop: Monitoring Exposure to Respirable Coal Mine Dust, 1969–2000

PubMed Central

Weeks, James L.

2003-01-01

Following passage of the Coal Mine Health and Safety Act of 1969, underground coal mine operators were required to take air samples in order to monitor compliance with the exposure limit for respirable dust, a task essential for the prevention of pneumoconiosis among coal workers. Miners objected, claiming that having the mine operators perform this task was like “having the fox guard the chicken coop.” This article is a historical narrative of mining industry corruption and of efforts to reform the program of monitoring exposure to coal mine dust. Several important themes common to the practice of occupational health are illustrated; most prominently, that employers should not be expected to regulate themselves. PMID:12893602

The MAGO experiment for dust environment monitoring on the Martian surface

NASA Astrophysics Data System (ADS)

Palumbo, P.; Battaglia, R.; Brucato, J. R.; Colangeli, L.; della Corte, V.; Esposito, F.; Ferrini, G.; Mazzotta Epifani, E.; Mennella, V.; Palomba, E.; Panizza, A.; Rotundi, A.

2004-01-01

Among the main directions identified for future Martian exploration, the study of the properties of dust dispersed in the atmosphere, its cycle and the impact on climate are considered of primary relevance. Dust storms, dust devils and the dust ``cycle'' have been identified and studied by past remote and in situ experiments, but little quantitative information is available on these processes, so far. The airborne dust contributes to the determination of the dynamic and thermodynamic evolution of the atmosphere, including the large-scale circulation processes and its impact on the climate of Mars. Moreover, aeolian erosion, redistribution of dust on the surface and weathering processes are mostly known only qualitatively. In order to improve our knowledge of the airborne dust evolution and other atmospheric processes, it is mandatory to measure the amount, mass-size distribution and dynamical properties of solid particles in the Martian atmosphere as a function of time. In this context, there is clearly a need for the implementation of experiments dedicated to study directly atmospheric dust. The Martian atmospheric grain observer (MAGO) experiment is aimed at providing direct quantitative measurements of mass and size distributions of dust particles, a goal that has never been fully achieved so far. The instrument design combines three types of sensors to monitor in situ the dust mass flux (micro balance system, MBS) and single grain properties (grain detection system, GDS+impact sensor, IS). Technical solutions and science capabilities are discussed in this paper.

Characterizing dust aerosols in the atmospheric boundary layer over the deserts in Northwest China: monitoring network and field observation

NASA Astrophysics Data System (ADS)

He, Q.; Matimin, A.; Yang, X.

2016-12-01

TheTaklimakan, Gurbantunggut and BadainJaran Deserts with the total area of 43.8×104 km2 in Northwest China are the major dust emission sources in Central Asia. Understanding Central Asian dust emissions and the interaction with the atmospheric boundary layer has an important implication for regional and global climate and environment changes. In order to explore these scientific issues, a monitoring network of 63 sites was established over the vast deserts (Taklimakan Desert, Gurbantunggut Desert and Badain Jaran Desert) in Northwest China for the comprehensive measurements of dust aerosol emission, transport and deposition as well as the atmospheric boundary layer including the meteorological parameters of boundary layer, surface radiation, surface heat fluxes, soil parameters, dust aerosol properties, water vapor profiles, and dust emission. Based on the monitoring network, the field experiments have been conducted to characterize dust aerosols and the atmospheric boundary layer over the deserts. The experiment observation indicated that depth of the convective boundary layer can reach 5000m on summer afternoons. In desert regions, the diurnal mean net radiation was effected significantly by dust weather, and sensible heat was much greater than latent heat accounting about 40-50% in the heat balance of desert. The surface soil and dust size distributions of Northwest China Deserts were obtained through widely collecting samples, results showed that the dominant dust particle size was PM100within 80m height, on average accounting for 60-80% of the samples, with 0.9-2.5% for PM0-2.5, 3.5-7.0% for PM0-10 and 5.0-14.0% for PM0-20. The time dust emission of Taklimakan Desert, Gurbantunggut Desert and Badain Jaran Desert accounted for 0.48%, 7.3%×10-5and 1.9% of the total time within a year, and the threshold friction velocity for dust emission were 0.22-1.06m/s, 0.29-1.5m/s and 0.21-0.59m/s, respectively.

ENVIRONMENTAL TECHNOLOGY REPORT - LEAD DUST WIPE MEASUREMENT TECHNOLOGY MONITORING TECHNOLOGIES INTERNATIONAL, PDV 5000 TRACE ELEMENT ANALYZER

EPA Science Inventory

ETV works in partnership with recognized standards and testing organizations and stakeholder groups consisting of regulators, buyers, and vendor organizations, with the full participation of individual technology developers. The program evaluates the performance of innovative

Estimating Children's Soil/Dust Ingestion Rates through ...

EPA Pesticide Factsheets

Background: Soil/dust ingestion rates are important variables in assessing children’s health risks in contaminated environments. Current estimates are based largely on soil tracer methodology, which is limited by analytical uncertainty, small sample size, and short study duration. Objectives: The objective was to estimate site-specific soil/dust ingestion rates through reevaluation of the lead absorption dose–response relationship using new bioavailability data from the Bunker Hill Mining and Metallurgical Complex Superfund Site (BHSS) in Idaho, USA. Methods: The U.S. Environmental Protection Agency (EPA) in vitro bioavailability methodology was applied to archived BHSS soil and dust samples. Using age-specific biokinetic slope factors, we related bioavailable lead from these sources to children’s blood lead levels (BLLs) monitored during cleanup from 1988 through 2002. Quantitative regression analyses and exposure assessment guidance were used to develop candidate soil/dust source partition scenarios estimating lead intake, allowing estimation of age-specific soil/dust ingestion rates. These ingestion rate and bioavailability estimates were simultaneously applied to the U.S. EPA Integrated Exposure Uptake Biokinetic Model for Lead in Children to determine those combinations best approximating observed BLLs. Results: Absolute soil and house dust bioavailability averaged 33% (SD ± 4%) and 28% (SD ± 6%), respectively. Estimated BHSS age-specific soil/du

Development of a Multianalyte Enzyme-Linked Immunosorbent Assay for Permethrin and Aroclors and Its Implementation for Analysis of Soil/Sediment and House Dust ExtractsExtracts

EPA Science Inventory

Development of a multianalyte enzyme-linked immunosorbent assay (ELISA) for detection of permethrin and aroclors 1248 or 1254, and implementation of the assay for analysis of soil/sediment samples are described. The feasibility of using the multianalyte ELISA to monitor aroclors ...

Exposures to thoracic particulate matter, endotoxin, and glucan during post-Hurricane Katrina restoration work, New Orleans 2005-2012.

PubMed

Rando, Roy J; Kwon, Cheol-Woong; Lefante, John J

2014-01-01

In the aftermath of Hurricane Katrina, which devastated the city of New Orleans in August 2005, restoration workers were at risk for respiratory illness from exposure to airborne particles and microbial agents. In support of an epidemiologic investigation of this risk, an exposure assessment for restoration work activities (demolition, trash & debris management, landscape restoration, sewer/waterline repair, and mold remediation) was performed from 2005 to 2012. For 2005 and 2006, Occupational Safety and Health Administration (OSHA) data (n = 730) for personal and area monitoring of total and respirable dust exposures of restoration workers were accessed and analyzed. The most significant exposures were for demolition work, with average respirable dust exposures in 2005 above the action level of 2.5 mg/m(3) and 17.6% of exposures exceeding the permissible exposure limit (PEL) (5 mg/m(3)). Additional personal and area monitoring for thoracic particulate matter was performed from 2007 to 2012 (n = 774) and samples were assayed for endotoxin and (1→3, 1→6)-β-D-glucan (n = 202). In order to integrate the OSHA data with the later monitoring data, three independent predictive models were developed to convert total and respirable dust measures into the equivalent thoracic dust. The three models were not statistically different and the modeling results were in good agreement with an overall coefficient of variation of 16% for the thoracic dust means across work activities estimated by each of the three models. Overall, thoracic dust exposure levels decreased by about an order of magnitude within the first year after Katrina and then more gradually declined and stabilized through 2012. Estimated average exposures to endotoxin and microbial glucan in 2005 were as high as 256 EU/m(3) and 118 μg/m(3), respectively, and likewise were seen to decrease dramatically and stabilize after 2005. The results of this exposure assessment support previously published reports of respiratory illness including sinusitis, toxic pneumonitis, and Katrina Cough among restoration workers in the years immediately after the hurricane.

Time-course monitoring of urban bioaerosol bacterial communities and its use in microbial hazard identification during Asian Dust events in Seoul, Korea

NASA Astrophysics Data System (ADS)

Park, J.

2015-12-01

The microbial communities transported by Asian dust events have attracted much attention as bioaerosols because the transported airborne microbes may strongly influence the downwind ecosystems and potentially human health in East Asia. Bioaerosol study has received relatively little attention and their characterization and risk assessments remain poorly developed. We used high throughput 16S rRNA gene targeted pyrosequencing and real-time quantitative PCR (qPCR) to monitor airborne bacterial communities and assess their potential risk. We monitored microbial communities in bioaerosol in Seoul between 2011 and 2013 using high volume air samplers. Six samples were collected during Asian dust (AD) events and the other 34 samples were urban air collected during non-Asian dust (non-AD) events. According to the qPCR result, the gene copy numbers of 16S rRNA genes were significantly higher during the AD events (P < 0.05) and their abundances were positively correlated with PM10 concentrations and bacterial diversities. The most abundant bacterial members (genus level) in the AD samples were Bacillus, Neisseria and E.coli/Shigella. To identify pathogenic populations, multilocus sequence typing (MLST) and virulence tests were applied using culture methods. 16S rRNA gene sequences of several pathogens were detected and their relative abundances appeared to have increased with increased concentrations of PM10. About 1% of Bacillus isolates were identified as known pathogenic B. cereus, confirming their presence in Asian dust samples. The qPCR detection of bceT gene, which codes for an enterotoxin in B. cereus group, was significantly increased in the AD dust samples over the non-AD samples. The following MLST assessment and virulence test of cultivated Bacillus isolates showed that B. cereus, B. licheniformis and B. mycoides were identified as pathogenic bacteria, and these pathogenic bacteria were usually more abundant during AD events. To assess the possible associations of identified pathogens on the hospital stroke admissions of residents in Seoul, we identified sixteen bioaerosol episodes using Poisson regression and calculated relative risk. The findings are useful in building a database for bacterial pathogens in AD events.

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.

Using Indium Tin Oxide To Mitigate Dust on Viewing Ports

NASA Technical Reports Server (NTRS)

2008-01-01

NASA plans to use a number of onboard viewing ports to measure lunar regolith in situ and to monitor robotic and human activities on the lunar or Martian surface. Because of the size and abundance of dust particles on these bodies, the potential for dust to occlude viewing ports and windows is high enough to threaten system lifetime and reliability, especially when activities rely on relaying video to either a habitat module or controllers on Earth. This project uses a technology being developed by KSC's Electrostatics and Surface Physics Laboratory to remove dust from windowlike surfaces. The technology applies an alternating electric potential to interlaced electrodes. In this application, we use indium tin oxide (ITO) to create various electrode patterns in order to determine the most reliable pattern for dust removal. This technology has application to systems where optical clarity is important. Specifically, this project considers the in situ resource utilization (ISRU) application of a viewing port for Raman spectroscopy, where the electrode pattern on glass would be coated with a scratch-resistant sapphire film (Al2O3).

Application of wind-profiling radar data to the analysis of dust weather in the Taklimakan Desert.

PubMed

Wang, Minzhong; Wei, Wenshou; Ruan, Zheng; He, Qing; Ge, Runsheng

2013-06-01

The Urumqi Institute of Desert Meteorology of the China Meteorological Administration carried out an atmospheric scientific experiment to detect dust weather using a wind-profiling radar in the hinterland of the Taklimakan Desert in April 2010. Based on the wind-profiling data obtained from this experiment, this paper seeks to (a) analyze the characteristics of the horizontal wind field and vertical velocity of a breaking dust weather in a desert hinterland; (b) calculate and give the radar echo intensity and vertical distribution of a dust storm, blowing sand, and floating dust weather; and (c) discuss the atmosphere dust counts/concentration derived from the wind-profiling radar data. Studies show that: (a) A wind-profiling radar is an upper-air atmospheric remote sensing system that effectively detects and monitors dust. It captures the beginning and ending of a dust weather process as well as monitors the sand and dust being transported in the air in terms of height, thickness, and vertical intensity. (b) The echo intensity of a blowing sand and dust storm weather episode in Taklimakan is about -1~10 dBZ while that of floating dust -1~-15 dBZ, indicating that the dust echo intensity is significantly weaker than that of precipitation but stronger than that of clear air. (c) The vertical shear of horizontal wind and the maintenance of low-level east wind are usually dynamic factors causing a dust weather process in Taklimakan. The moment that the low-level horizontal wind field finds a shear over time, it often coincides with the onset of a sand blowing and dust storm weather process. (d) When a blowing sand or dust storm weather event occurs, the atmospheric vertical velocity tends to be of upward motion. This vertical upward movement of the atmosphere supported with a fast horizontal wind and a dry underlying surface carries dust particles from the ground up to the air to form blown sand or a dust storm.

The Generation Rate of Respirable Dust from Cutting Fiber Cement Siding Using Different Tools

PubMed Central

Qi, Chaolong; Echt, Alan; Gressel, Michael G

2017-01-01

This article describes the evaluation of the generation rate of respirable dust (GAPS, defined as the mass of respirable dust generated per unit linear length cut) from cutting fiber cement siding using different tools in a laboratory testing system. We used an aerodynamic particle sizer spectrometer (APS) to continuously monitor the real-time size distributions of the dust throughout cutting tests when using a variety of tools, and calculated the generation rate of respirable dust for each testing condition using the size distribution data. The test result verifies that power shears provided an almost dust-free operation with a GAPS of 0.006 gram meter−1 (g m−1) at the testing condition. For the same power saws, the cuts using saw blades with more teeth generated more respirable dusts. Using the same blade for all four miter saws tested in this study, a positive linear correlation was found between the saws’ blade rotating speed and its dust generation rate. In addition, a circular saw running at the highest blade rotating speed of 9068 RPM generated the greatest amount of dust. All the miter saws generated less dust in the ‘chopping mode’ than in the ‘chopping and sliding’ mode. For the tested saws, GAPS consistently decreased with the increases of the saw cutting feed rate and the number of board in the stack. All the test results point out that fewer cutting interactions between the saw blade’s teeth and the siding board for a unit linear length of cut tend to result in a lower generation rate of respirable dust. These results may help guide optimal operation in practice and future tool development aimed at minimizing dust generation while producing a satisfactory cut. PMID:28395343

The Generation Rate of Respirable Dust from Cutting Fiber Cement Siding Using Different Tools.

PubMed

Qi, Chaolong; Echt, Alan; Gressel, Michael G

2017-03-01

This article describes the evaluation of the generation rate of respirable dust (GAPS, defined as the mass of respirable dust generated per unit linear length cut) from cutting fiber cement siding using different tools in a laboratory testing system. We used an aerodynamic particle sizer spectrometer (APS) to continuously monitor the real-time size distributions of the dust throughout cutting tests when using a variety of tools, and calculated the generation rate of respirable dust for each testing condition using the size distribution data. The test result verifies that power shears provided an almost dust-free operation with a GAPS of 0.006 g m-1 at the testing condition. For the same power saws, the cuts using saw blades with more teeth generated more respirable dusts. Using the same blade for all four miter saws tested in this study, a positive linear correlation was found between the saws' blade rotating speed and its dust generation rate. In addition, a circular saw running at the highest blade rotating speed of 9068 rpm generated the greatest amount of dust. All the miter saws generated less dust in the 'chopping mode' than in the 'chopping and sliding' mode. For the tested saws, GAPS consistently decreased with the increases of the saw cutting feed rate and the number of board in the stack. All the test results point out that fewer cutting interactions between the saw blade's teeth and the siding board for a unit linear length of cut tend to result in a lower generation rate of respirable dust. These results may help guide optimal operation in practice and future tool development aimed at minimizing dust generation while producing a satisfactory cut. Published by Oxford University Press on behalf of The British Occupational Hygiene Society 2017.

Comparison of Respirable Mass Concentrations Measured by a Personal Dust Monitor and a Personal DataRAM to Gravimetric Measurements.

PubMed

Halterman, Andrew; Sousan, Sinan; Peters, Thomas M

2017-12-15

In 2016, the Mine Safety and Health Administration required the use of continuous monitors to measure respirable dust in mines and better protect miner health. The Personal Dust Monitor, PDM3700, has met stringent performance criteria for this purpose. In a laboratory study, respirable mass concentrations measured with the PDM3700 and a photometer (personal DataRam, pDR-1500) were compared to those measured gravimetrically for five aerosols of varying refractive index and density (diesel exhaust fume, welding fume, coal dust, Arizona road dust (ARD), and salt [NaCl] aerosol) at target concentrations of 0.38, 0.75, and 1.5 mg m-3. For all aerosols except coal dust, strong, near-one-to-one, linear relationships were observed between mass concentrations measured with the PDM3700 and gravimetrically (diesel fume, slope = 0.99, R2 = 0.99; ARD, slope = 0.98, R2 = 0.99; and NaCl, slope = 0.95, R2 = 0.99). The slope deviated substantially from unity for coal dust (slope = 0.55; R2 = 0.99). Linear relationships were also observed between mass concentrations measured with the pDR-1500 and gravimetrically, but one-to-one behavior was not exhibited (diesel fume, slope = 0.23, R2 = 0.76; coal dust, slope = 0.54, R2 = 0.99; ARD, slope = 0.61, R2 = 0.99; NaCl, slope = 1.14, R2 = 0.98). Unlike the pDR-1500, mass concentrations measured with the PDM3700 appear independent of refractive index and density, suggesting that it could have applications in a variety of occupational settings. © The Author(s) 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Mimicking Martian dust: An in-vacuum dust deposition system for testing the ultraviolet sensors on the Curiosity rover.

PubMed

Sobrado, J M; Martín-Soler, J; Martín-Gago, J A

2015-10-01

We have designed and developed an in-vacuum dust deposition system specifically conceived to simulate and study the effect of accumulation of Martian dust on the electronic instruments of scientific planetary exploration missions. We have used this device to characterize the dust effect on the UV sensor of the Rover Environmental Monitoring Station in the Mars science Laboratory mission of NASA in similar conditions to those found on Mars surface. The UV sensor includes six photodiodes for measuring the radiation in all UV wavelengths (direct incidence and reflected); it is placed on the body of Curiosity rover and it is severely affected by the dust deposited on it. Our experimental setup can help to estimate the duration of reliable reading of this instrument during operation. We have used an analogous of the Martian dust in chemical composition (magnetic species), color, and density, which has been characterized by X-ray spectroscopy. To ensure a Brownian motion of the dust during its fall and a homogeneous coverage on the instrumentation, the operating conditions of the vacuum vessel, determined by partial pressures and temperature, have to be modified to account for the different gravities of Mars with respect to Earth. We propose that our designed device and operational protocol can be of interest to test optoelectronic instrumentation affected by the opacity of dust, as can be the degradation of UV photodiodes in planetary exploration.

Mimicking Martian dust: An in-vacuum dust deposition system for testing the ultraviolet sensors on the Curiosity rover

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

Sobrado, J. M., E-mail: sobradovj@inta.es; Martín-Soler, J.; Martín-Gago, J. A.

We have designed and developed an in-vacuum dust deposition system specifically conceived to simulate and study the effect of accumulation of Martian dust on the electronic instruments of scientific planetary exploration missions. We have used this device to characterize the dust effect on the UV sensor of the Rover Environmental Monitoring Station in the Mars science Laboratory mission of NASA in similar conditions to those found on Mars surface. The UV sensor includes six photodiodes for measuring the radiation in all UV wavelengths (direct incidence and reflected); it is placed on the body of Curiosity rover and it is severelymore » affected by the dust deposited on it. Our experimental setup can help to estimate the duration of reliable reading of this instrument during operation. We have used an analogous of the Martian dust in chemical composition (magnetic species), color, and density, which has been characterized by X-ray spectroscopy. To ensure a Brownian motion of the dust during its fall and a homogeneous coverage on the instrumentation, the operating conditions of the vacuum vessel, determined by partial pressures and temperature, have to be modified to account for the different gravities of Mars with respect to Earth. We propose that our designed device and operational protocol can be of interest to test optoelectronic instrumentation affected by the opacity of dust, as can be the degradation of UV photodiodes in planetary exploration.« less

The Lunar Environment: Determining the Health Effects of Exposure to Moon Dusts

NASA Technical Reports Server (NTRS)

Khan-Mayberry, Noreen

2007-01-01

The Earth s moon presents a hostile environment in which to live and work. There is no atmosphere to protect its surface from the ravages of solar wind and micrometeorite impacts. As a result, the moon s surface is covered with a thin layer of fine, charged, reactive dust capable of entering habitats and vehicle compartments, where it can result in crewmember health problems. During the Apollo missions, lunar dusts were introduced into the crew vehicle, resulting in direct exposure and occasional reports of respiratory, dermal and ocular irritation. In order to study the toxicological effects of lunar dust, NASA formed the Lunar Airborne Dust Toxicity Advisory Group (LADTAG). This interdisciplinary group is comprised of leading experts in space toxicology, lunar geology, space medicine and biomedical research. LADTAG has demonstrated that lunar soil contains several types of reactive dusts, including an extremely fine respirable component. These dusts have highly reactive surfaces in the lunar environment; the grains contain surface coatings which are generated by vapor phases formed by hypervelocity impact of micrometeorites. This unique class of dusts has surface properties that are unlike any Earth based analog. These distinctive properties are why lunar dusts are of great toxicological interest. Understanding how these reactive components behave "biochemically" in a moisture-rich pulmonary environment will aid in determining how toxic these particles are to humans. The data obtained from toxicological examination of lunar dusts will determine the human risk criteria for lunar dust exposure and produce a lunar health standard. LADTAG s analysis of lunar dusts and lunar dust simulants will include detailed lunar particle characterizations, determining the properties of particle activation, reactivation of lunar dust, the process of dust passivation and discerning the pathology of lunar dust exposure via inhalation, intratracheal instillation, cell culture exposure, dermal exposure and ocular exposure. The resulting health standard will be time-based and will vary by the duration and type of exposure. It may also be necessary to set multiple standards for different types of lunar dust, as well as for dust in its activated form vs. aged & passivated dust. This standard, set to protect the health of our robust astronaut crews, will not only impact NASA medical operations, but engineering designs as well. The data from our multidisciplinary research are vital in developing remediation devices and environmental monitors. Ultimately, the engineering and safety groups will design and develop countermeasures for space vehicles, suits, rovers and habitats that will be sustained within the limits of the health standard.

Dust Impact Monitor (SESAME-DIM) on-board Rosetta/Philae: Aerogel as comet analog material

NASA Astrophysics Data System (ADS)

Flandes, Alberto; Albin, Thomas; Arnold, Walter; Fischer, Hans-Herbert; Hirn, Attila; Loose, Alexander; Mewes, Cornelia; Podolak, Morris; Seidensticker, Klaus J.; Volkert, Cynthia; Krüger, Harald

2018-03-01

On 12 November 2014, during the descent of the Rosetta lander Philae to the surface of comet 67P/Churyumov-Gerasimenko the Dust Impact Monitor (DIM) on board Philae recorded an impact of a cometary dust impact of a cometary dust particle at 2.4 km from the comet surface (5 km from the nucleus' barycentre). In this work, we report further experiments that support the identification of this particle. We use aerogel as a comet analog material to characterise the properties of this particle. Our experiments show that this particle has a radius of 0.9 mm, a low density of 0.25 g/cm3 and a high porosity close to 90%. The particle likely moved at near 4 m/s with respect to the comet.

76 FR 12648 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-08

... be appropriate to use on a short-term basis. 13. The proposed rule addresses (1) which occupations... for respirable coal mine dust, provide for full- shift sampling, redefine the term ``normal production... respect to their availability. If shorter or longer timeframes are recommended, please provide the...

Industrial hygiene monitoring needs for the coal conversion and oil shale industries. Study group report

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

White, Otto; Morris, Samuel; Cessario, Thomas R.

1979-11-01

Conclusions of a study group organized to assess the need for research and development of instrumentation for monitoring occupational exposures in the coal conversion and oil shale industries are reported. Research and development requirements for assessing potentially hazardous exposures are reviewed. Hazardous substances are classified in the following four categories: those which are immediately hazardous to life and health; high risk, but not immediately hazardous; moderate risk and not immediately hazardous; and short-term, nonroutine high hazards. Specific research recommendations are made in the following areas: personal monitors for gases; nitrogen compounds; aerosols; metals; fibers and dust; surface contamination; skin contamination;more » analytical development; industrial hygiene surveys;research; and, bioassays. (JGB)« less

Lunar Dust and Lunar Simulant Activation, Monitoring, Solution and Cellular Toxicity Properties

NASA Technical Reports Server (NTRS)

Jeevarajan, A.S.; Wallace, W.T.

2009-01-01

During the Apollo missions, many undesirable situations were encountered that must be mitigated prior to returning humans to the moon. Lunar dust (that part of the lunar regolith less than 20 m in diameter) was found to produce several problems with astronaut s suits and helmets, mechanical seals and equipment, and could have conceivably produced harmful physiological effects for the astronauts. For instance, the abrasive nature of the dust was found to cause malfunctions of various joints and seals of the spacecraft and suits. Additionally, though efforts were made to exclude lunar dust from the cabin of the lunar module, a significant amount of material nonetheless found its way inside. With the loss of gravity correlated with ascent of the lunar module from the lunar surface to rendezvous with the command module, much of the major portions of the contaminating soil and dust began to float, irritating the astronaut s eyes and being inhaled into their lungs. Our goal has been to understand some of the properties of lunar dust that could lead to possible hazards for humans. Due to the lack of an atmosphere, there is nothing to protect the lunar soil from ultraviolet radiation, solar wind, and meteorite impacts. These processes could all serve to activate the soil, or produce reactive surface species. In order to understand the possible toxic effects of the reactive dust, it is necessary to reactivate the dust, as samples returned during the Apollo missions were exposed to the atmosphere of the Earth. We have used grinding and UV exposure to mimic some of the processes occurring on the Moon. The level of activation has been monitored using two methods: fluorescence spectroscopy and electron paramagnetic resonance spectroscopy (EPR). These techniques allow the monitoring of hydroxyl radical production in solution. We have found that grinding of lunar dust produces 2-3 times the concentration of hydroxyl radicals as lunar simulant and 10 times that of quartz. Exposure of the lunar dust to UV radiation under vacuum was also found to lead to hydroxyl radical production. After grinding, we have also monitored loss of reactivity of the dusts by exposing them to conditions of known humidity and temperature. From these tests, it was found that the reactivity half-life of lunar simulant is approximately 3 hours, while that of quartz is approximately 2 hours. Placing lunar dust in solution could lead to effects on mechanical and physiological systems, as well as other biological systems. For instance, while it is known that lunar dust is highly abrasive and caused a variety of problems with suits and equipment during Apollo, it is unknown as to how these properties might be affected in the presence of water or other liquids. It is possible that the dust may release minerals (e.g., metallic nanophase Fe) into solution that could speed corrosion or rust. Also, as lunar dust produces hydroxyl radicals (and possibly other reactive oxygen species) in solution, these radicals could also lead to the breakdown of suit or habitat materials. In the body (i.e., in lung solution), the effects could be two-fold. First, if the lunar dust dissolves, it may release an excess of elements (such as zero-valence metallic Fe) that are necessary for bodily functions but only in certain concentration ranges. For lunar dust, the presence of nanophase iron being released into the body is a concern. Secondly, the hydroxyl radicals or other reactive oxygen species produced by the dust in solution could conceivably interact with cells, leading to various problems. We have studied the dissolution of both ground and unground lunar simulant in buffer solutions of different pH. The concentration of a number of species was determined using mass spectrometry. These studies showed that lowering the pH of the solution causes a dramatic increase in the amount of each element released into solution and that grinding also produces higher concentrations. Finally, we have perfmed initial tests aimed at understanding the effects of lunar simulant on cellular systems. Alveolar epithelial cells were cultured and exposed to different concentrations of dust suspended in cell culture media. After predetermined amounts of time, the media was removed and the concentrations of important inflammatory cytokines (IL6, IL8, and TNF-alpha ) were measured. The results of these tests are being used to develop the correct protocols for tests to be performed using lunar dust samples.

Analysis of water ice and water ice/soil mixtures using laser-induced breakdown spectroscopy: application to Mars polar exploration.

PubMed

Arp, Zane A; Cremers, David A; Wiens, Roger C; Wayne, David M; Sallé, Béatrice; Maurice, Sylvestre

2004-08-01

Recently, laser-induced breakdown spectroscopy (LIBS) has been developed for the elemental analysis of geological samples for application to space exploration. There is also interest in using the technique for the analysis of water ice and ice/dust mixtures located at the Mars polar regions. The application is a compact instrument for a lander or rover to the Martian poles to interrogate stratified layers of ice and dusts that contain a record of past geologic history, believed to date back several million years. Here we present results of a study of the use of LIBS for the analysis of water ice and ice/dust mixtures in situ and at short stand-off distances (< 6.5 m) using experimental parameters appropriate for a compact instrument. Characteristics of LIBS spectra of water ice, ice/soil mixtures, element detection limits, and the ability to ablate through ice samples to monitor subsurface dust deposits are discussed.

Martian Dust Storm on May 18, 2008

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Click on image for animation

This false-color polar map was generated from images obtained by the Mars Reconnaissance Orbiter's Mars Color Imager (MARCI) on May 18, 2008. It shows a large local dust storm that researchers were monitoring to see if it would affect weather conditions at NASA's Phoenix spacecraft's landing site on landing day, May 25, 2008. The landing site is labeled and marked with the yellow dot.

The dust storm, indicated with yellow arrows in the close-up view, is the sinuous, light-colored feature to the left of the white northern polar cap at the center of the map.

This dust storm was too early and too far away to affect the lander.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

A thorough analysis of a severe dust storm in the Arabian Peninsula using WRF-CHEM, satellite imagery, and ground observations

NASA Astrophysics Data System (ADS)

Karagulian, F.; Ghebreyesus, D. T.; Weston, M.; Krishnan, V.; Temimi, M.; Al Hammadi, F.; Al Abdooli, A.

2017-12-01

A strong dust event occurred over the Arabian Peninsula from 1 to 3 April 2015. The event impacted the United Arab Emirates (UAE) on 2 April 2015 in the form of a dust storm. The origin and synopsis of the event is investigated in this study together with its impact on Air Quality in the UAE. The Weather Research Forecasting model coupled with chemistry (WRF-Chem) was run for the dates of the dust event. Outputs of the model were assessed against ground measurements of Particulate Matter (PM10) from monitoring stations in the United Arab Emirates (UAE), meteorological data, and the Aerosol Optical Depth from the new 1 km Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm for MODIS Terra and Aqua at 0.55 mm. Data from the geo-stationary satellite MSG SEVIRI was used to track the extent and the trajectory of the dust event across the Arabian Peninsula. This was supported by HYSPLIT back trajectory analysis simulated on hourly basis. The modeled results favorably agreed with ground observations of meteorological parameters at several monitoring stations in the UAE. On 2 and 3 April 2015, measurements and WRF-Chem simulations over the UAE showed northwest wind blowing within the range of 11-14 m s-1. Average surface temperature decreased from 33 to 26 ºC and the average radiance dropped by 50% during the peak time of the dust event with consequent reduction of the observed visibility down to 200 m in some UAE's cities. At local level, comparisons between modeled and estimated PM10 concentrations from monitoring stations and satellite data were somewhat biased by the saturated values recorded during the peak time of the dust event on 2 April 2015 with modeled lower limit average PM10 concentrations of 432 mg/m3 that were 25% lower than the ones from monitoring stations. On regional scale, the WRF-Chem model was able to estimate an upper limit values of PM10 concentrations during the dust event.

Lunar Dust Monitor for the orbiter of the next Japanese lunar mission SELENE2

NASA Astrophysics Data System (ADS)

Hirai, Takayuki; Sasaki, Sho; Ohashi, Hideo; Kobayashi, Masanori; Fujii, Masayuki; Shibata, Hiromi; Iwai, Takeo; Nogami, Ken-Ichi; Kimura, Hiroshi; Nakamura, Maki

2010-05-01

The next Japanese lunar mission SELENE2, after a successful mission Kaguya (a project named SELENE), is planned to launch in mid 2010 and to consists of a lander, a rover, and an orbiter, as a transmitting satellite to the earth [1]. A dust particle detector is proposed to be onboard the orbiter that is planned to be in operation for one year or more. Dust particles around the Moon include interplanetary dust, beta-meteoroids, interstellar dust, and possibly lunar dust that originate from the subsurface materials of the Moon. It is considered that several tens of thousands of tons of dust particles per year fall onto the Moon and supply materials to its surface layer. "Inflow" and "outflow" dust particles are very important for understanding material compositions of lunar surface. In past missions, dust detectors onboard the Hiten and Nozomi (Hiten-MDC and Nozomi-MDC) measured the flues of dust particles in the lunar orbit [2, 3]. These observations by Hiten- and Nozomi-MDCs created a small dataset of statistics of dust particles excluding earth-orbiting dust once in a week, because the dust detectors had small sensitive areas, 0.01 m2 and 0.014 m^2, respectively. The Lunar Dust EXperiment (LDEX) is designed to map a spatial and temporal variability of the dust size and density distributions in the lunar environment and will be onboard LADEE, which will be launched in 2012 [4]. LDEX will observe the lunar environment for 90 days in a nominal case or for a maximum of 9 months. It has a sensor area of 0.01 m2 at 50 km altitude. For a quantitative study of circumlunar dust, we propose a dust monitoring device with a large aperture size and a large sensor area, called the lunar dust monitor (LDM). The LDM is an impact ionization detector with dimensions 25 cm × 25 cm × 30 cm, and it has a large target (gold-plated Al) of 400 cm^2, to which a high voltage of +500 V is applied. The LDM also has two meshed grids parallel to the target. The grids are 90% transparent: the inner grid is 2 cm apart from the target and the outer grid is 15 cm from the target. We can deduce the mass and velocity information of the impacted dust particle from the recorded signal waveforms generated by the impacts of dust particles. Dust particles around the Moon are classified based on their origins: interstellar dust, interplanetary dust, beta meteoroids, and possibly dust that originated on the Moon. They can be inferred from their kinematic properties: the velocities and the arrival directions. If the proportion of dust components around the Moon is determined by observation, we can increase our knowledge of the contribution of inflow and outflow dust particles to lunar surface materials. References: [1] Matsumoto, K. et al., Joint Annual Meeting of LEAG-ICEUM-SRR (2008) LPI Contribution No.1446, 86. [2] Iglseder H. et al., Adv. Space Res. 17 (1996) 177-182. [3] Sasaki S., et al., Adv. Space Res., 39 (2007), 485-488. [4] Horanyi, M. et al., (2009) LPSC 40th, Abstract #1741.

The Dust at Altitude Recovery Technology (DART) System was Developed to Recover Plant, Human, and Animal Pathogens in Asian and African Dust Storms over North America

NASA Astrophysics Data System (ADS)

Schuerger, A. C.; Tench, B.; Nehr, A.; Emmons, T.; Valbuena, F.; Palaia, J.; Sugars, C.

2014-12-01

Dust emanates year-round from Africa and Asia and impacts air quality in North America. Asian dust plumes deliver up to 64 million tonnes of dust over the NW of the USA, and African dust storms deliver over 50 million tonnes of dust over Florida each year. Several recent studies have demonstrated that human and plant pathogens from Asian [1] African [2] aerosols can be transported to N. America in naturally occurring dust storms. What is unknown is whether these 'presumptive pathogens' impact human, plant, or animal health in the USA. In order to initiate a long-term monitoring program of pathogens in Asian and African dust plumes, we have developed a dust collection system called DART (Dust at Altitude Recovery Technology) (figure). The DART dust sampler can be mounted on a F104 Starfighter jet (figure) and a T6 Texan propeller driven airplane (not shown), and was test flown over FL in Dec. 2013 on the F104 and on the T6 in the summer of 2014. The DART system utilizes a high-volume pump to pass air through 6 separate filtration units where both aerosols and microbial cells are captured. The filtration systems exhibit flow rates from 25-142 L/min depending on the pore size and brand of filters used. Flow rates are directly correlated to increased air speed, and are inversely correlated to increased altitude. Filtration units can be turned on and off individually as required for specific science flight objectives. The DART dust sampler has performed nominally up to 7600 m, 0.92 Mach, and 3.5 +G's. During initial test flights in Dec. 2013, 5 of 8 genera of fungi recovered from the lower atmosphere over FL contained plant pathogens including species in the genera: Acremonium, Aspergillus, Cladosporium, Curvularia, and Fusarium. Numbers of recovered fungi, but not bacteria, increased significantly when 5 or 10 µm filters were used in the DART system compared to filter pore sizes ≤ 1.2 µm. Future sampling programs for both Asian and African dust events will be discussed. References: [1] Smith, D. J., et al., 2012. Microbial Ecology 64,973-985. [2] Griffin, D. W. 2007, Clinical Microbiology Reviews 20, 459-477.

Enhancing wind erosion monitoring and assessment for U.S. rangelands

USGS Publications Warehouse

Webb, Nicholas P.; Van Zee, Justin W.; Karl, Jason W.; Herrick, Jeffrey E.; Courtright, Ericha M.; Billings, Benjamin J.; Boyd, Robert C.; Chappell, Adrian; Duniway, Michael C.; Derner, Justin D.; Hand, Jenny L.; Kachergis, Emily; McCord, Sarah E.; Newingham, Beth A.; Pierson, Frederick B.; Steiner, Jean L.; Tatarko, John; Tedela, Negussie H.; Toledo, David; Van Pelt, R. Scott

2017-01-01

On the GroundWind erosion is a major resource concern for rangeland managers because it can impact soil health, ecosystem structure and function, hydrologic processes, agricultural production, and air quality.Despite its significance, little is known about which landscapes are eroding, by how much, and when.The National Wind Erosion Research Network was established in 2014 to develop tools for monitoring and assessing wind erosion and dust emissions across the United States.The Network, currently consisting of 13 sites, creates opportunities to enhance existing rangeland soil, vegetation, and air quality monitoring programs.Decision-support tools developed by the Network will improve the prediction and management of wind erosion across rangeland ecosystems.

Field Measurements and Modeling of Dust Transport and Deposition on a Hawaiian Volcano

NASA Astrophysics Data System (ADS)

Douglas, M.; Stock, J. D.; Cerovski-Darriau, C.; Bishaw, K.; Bedford, D.

2017-12-01

The western slopes of Hawaii's Mauna Kea volcano are mantled by fine-grained soils that record volcanic airfall and eolian deposition. Where exposed, strong winds transport this sediment across west Hawaii, affecting tourism and local communities by decreasing air and water quality. Operations on US Army's Ke'amuku Maneuver Area (KMA) have the potential to increase dust flux from these deposits. To understand regional dust transport and composition, the USGS established 18 ground monitoring sites and sampling locations surrounding KMA. For over three years, each station measured vertical and horizontal dust flux while co-located anemometers measured wind speed and direction. We use these datasets to develop a model for dust supply and transport to assess whether KMA is a net dust sink or source. We find that horizontal dust flux rates are most highly correlated with entrainment threshold wind speeds of 8 m/s. Using a dust model that partitions measured horizontal dust flux into inward- and outward-directed components, we predict that KMA is currently a net dust sink. Geochemical analysis of dust samples illustrates that organics and pedogenic carbonate make up to 70% of their mass. Measured vertical dust deposition rates of 0.005 mm/m2/yr are similar to deposition rates of 0.004 mm/m2/yr predicted from the divergence of dust across KMA's boundary. These rates are low compared to pre-historic rates of 0.2-0.3 mm/yr estimated from radiocarbon dating of buried soils. Therefore, KMA's soils record persistent deposition both over past millennia and at present at rates that imply infrequent, large dust storms. Such events led to soil-mantled topography in an otherwise rocky Pleistocene volcanic landscape. A substantial portion of fine-grained soils in other leeward Hawaiian Island landscapes may have formed from similar eolian deposition, and not direct weathering of parent rock.

A smart dust biosensor powered by kinesin motors.

PubMed

Fischer, Thorsten; Agarwal, Ashutosh; Hess, Henry

2009-03-01

Biosensors can be miniaturized by either injecting smaller volumes into micro- and nanofluidic devices or immersing increasingly sophisticated particles known as 'smart dust' into the sample. The term 'smart dust' originally referred to cubic-millimetre wireless semiconducting sensor devices that could invisibly monitor the environment in buildings and public spaces, but later it also came to include functional micrometre-sized porous silicon particles used to monitor yet smaller environments. The principal challenge in designing smart dust biosensors is integrating transport functions with energy supply into the device. Here, we report a hybrid microdevice that is powered by ATP and relies on antibody-functionalized microtubules and kinesin motors to transport the target analyte into a detection region. The transport step replaces the wash step in traditional double-antibody sandwich assays. Owing to their small size and autonomous function, we envision that large numbers of such smart dust biosensors could be inserted into organisms or distributed into the environment for remote sensing.

Air Quality Monitoring and Forecasting Applications of Suomi NPP VIIRS Aerosol Products

NASA Astrophysics Data System (ADS)

Kondragunta, Shobha

The Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument was launched on October 28, 2011. It provides Aerosol Optical Thickness (AOT) at two different spatial resolutions: a pixel level (~750 m at nadir) product called the Intermediate Product (IP) and an aggregated (~6 km at nadir) product called the Environmental Data Record (EDR), and a Suspended Matter (SM) EDR that provides aerosol type (dust, smoke, sea salt, and volcanic ash) information. An extensive validation of VIIRS best quality aerosol products with ground based L1.5 Aerosol Robotic NETwork (AERONET) data shows that the AOT EDR product has an accuracy/precision of -0.01/0.11 and 0.01/0.08 over land and ocean respectively. Globally, VIIRS mean AOT EDR (0.20) is similar to Aqua MODIS (0.16) with some important regional and seasonal differences. The accuracy of the SM product, however, is found to be very low (20 percent) when compared to Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) and AERONET. Several algorithm updates which include a better approach to retrieve surface reflectance have been developed for AOT retrieval. For dust aerosol type retrieval, a new approach that takes advantage of spectral dependence of Rayleigh scattering, surface reflectance, dust absorption in the deep blue (412 nm), blue (440 nm), and mid-IR (2.2 um) has been developed that detects dust with an accuracy of ~80 percent. For smoke plume identification, a source apportionment algorithm that combines fire hot spots with AOT imagery has been developed that provides smoke plume extent with an accuracy of ~70 percent. The VIIRS aerosol products will provide continuity to the current operational use of aerosol products from Aqua and Terra MODIS. These include aerosol data assimilation in Naval Research Laboratory (NRL) global aerosol model, verification of National Weather Service (NWS) dust and smoke forecasts, exceptional events monitoring by different states, air quality warnings by Environmental Protection Agency (EPA). This talk will provide an overview of VIIRS algorithms, aerosol product validation, and examples of various applications with a discussion on the relevance of product accuracy.

Dust Flux Monitor Instrument for the Stardust mission to comet Wild 2

NASA Astrophysics Data System (ADS)

Tuzzolino, A. J.; Economou, T. E.; McKibben, R. B.; Simpson, J. A.; McDonnell, J. A. M.; Burchell, M. J.; Vaughan, B. A. M.; Tsou, P.; Hanner, M. S.; Clark, B. C.; Brownlee, D. E.

2003-10-01

The Dust Flux Monitor Instrument (DFMI) is part of the Stardust instrument payload. The prime goal of the DFMI is to measure the particle flux, intensity profile, and mass distribution during passage through the coma of comet Wild 2 in January 2004. This information is valuable for assessment of spacecraft risk and health and also for interpretation of the laboratory analysis of dust captured by the Aerogel dust collectors and returned to Earth. At the encounter speed of 6.1 km/s, the DFMI measurements will extend over the particle mass range of 8 decades, from 10-11 to >10-3 g. A secondary science goal is to measure the particle flux and mass distribution during the ~7 year interplanetary portions of the mission, where, in addition to measurements of the background interplanetary dust over the radial range 0.98 AU to 2.7 AU, multiple opportunities exist for possible detection by the DFMI of interplanetary meteor-stream particles and interstellar dust. The DFMI consists of two different dust detector systems: a polyvinylidene fluoride (PVDF) Dust Sensor Unit (SU), which measures particles with mass <~10-4 g, and a Dual Acoustic Sensor System (DASS), which utilizes two quartz piezoelectric accelerometers mounted on the first two layers of the spacecraft Whipple dust shield to measure the flux of particles with mass >10-4 g. The large Whipple shield structures provide the large effective sensitive area required for detection of the expected low flux of high-mass particles.

Optical Embedded Dust Sensor for Engine Protection and Early Warning on M1 Abrams/Ground Combat Vehicles

DTIC Science & Technology

2012-04-11

warning of seal leakage or deterioration of air filters, thereby reducing engine damage and improving vehicle operational readiness. To be effective , the...for a comprehensive early warning and health management solution. To address the need for an effective dust detector for the AGT1500 engine and M1...an optical dust sensor for real-time continuous monitoring, and its effectiveness in quantitatively measuring dust penetration in the AGT1500 engine

Airborne Dust Monitoring Activities at the National Environmental Satellite, Data and Information Service

NASA Astrophysics Data System (ADS)

Stephens, G.; McNamara, D.; Taylor, J.

2002-12-01

Wind blown dust can be a hazard to transportation, industrial, and military operations, and much work has been devoted to its analysis and prediction from a meteorological viewpoint. The detection and forecasting of dust outbreaks in near real time is difficult, particularly in remote desert areas with sparse observation networks. The Regional Haze Regulation, passed by Congress in 1999, mandates a reduction in man made inputs to haze in 156 Class I areas (national parks and wilderness areas). Studies have demonstrated that satellite data can be useful in detection and tracking of dust storms. Environmental satellites offer frequent coverage of large geographic areas. The National Environmental Satellite, Data, and Information Service (NESDIS) of the U.S. National Oceanic and Atmospheric Administration (NOAA) operates a system of polar orbiting and geostationary environmental satellites, which sense data in two visible and three infrared channels. Promising results in the detection of airborne dust have been obtained using multispectral techniques to combine information from two or more channels to detect subtle spectral differences. One technique, using a ratio of two thermal channels, detects the presence of airborne dust, and discriminates it from both underlying ground and meteorological clouds. In addition, NESDIS accesses and is investigating for operational use data from several other satellites. The Total Ozone Mapping Spectrometer on board NASA's Earth Probe mission provides an aerosol index product which can detect dust and smoke, and the Moderate Resolution Imaging Spectroradiometer on NASA's Terra and Aqua satellites provide several channels which can detect aerosols in multispectral channel combinations. NESDIS, in cooperation with NOAA's Air Resources Laboratory, produces a daily smoke transport forecast, combining satellite derived smoke source points with a mathematical transport prediction model; such a scheme could be applied to other aerosol particles such as dust. Techniques effective for the monitoring of airborne dust are used operationally by NESDIS and the National Centers for Environmental Prediction at the Washington Volcanic Ash Advisory Center, which monitors the presence of airborne volcanic ash, optically similar to airborne dust.

Original monitoring of desert dust in African air masses transported over the Mediterranean Sea by quasi-Lagrangian drifting balloons and sounding balloons during the summer 2013 ChArMEx field campaign

NASA Astrophysics Data System (ADS)

Dulac, F.; Renard, J. B.; Durand, P.; Denjean, C.; Bourgeois, Q.; Vignelles, D.; Jeannot, M.; Mallet, M.; Verdier, N.

2017-12-01

This study focuses on in situ balloon-borne measurements of mineral dust from summer regional field campaigns in the western Mediterranean basin performed in the framework of ChArMEx (the Chemistry and Aerosol Mediterranean Experiment; see special issue https://www.atmos-chem-phys.net/special_issue334.html). Due to long-range transport from Africa, the lower troposphere over this regional sea is subject to high levels of desert dust with a maximum during the long dry and sunny Mediterranean summer season. Based on developments of boundary-layer pressurized balloons (BLPBs) and of a dedicated optical particle counter named LOAC (Light Optical Aerosol Counter/sizer), we were able to perform original quasi-Lagrangian monitoring of desert dust aerosols over the sea. The strategy combined classical sounding balloons and drifting BLPBs to document both the vertical distribution and long-range transport. A total of 27 LOAC flights were successfully conducted from Minorca Isl. (Spain) or Levant Isl. (France), during 4 Saharan dust transport events, including 10 flights with BLPBs at drifting altitudes between 2.0 and 3.3 km above sea level. The longest flight exceeded 700 km and lasted more than 25 h. Numerous tests and validations of LOAC measurements were performed to qualify the instrument, including comparisons with concurrent airborne measurements, sounding balloons, and remote sensing measurements with an AERONET sun-photometer, and a ground-based and the CALIOP lidar systems. Aerosol optical depths in the balloon vicinity did not exceed about 0.4 but the presence of turbid dust layers was confirmed thanks to dual scattering angle measurements by LOAC allowing the identification of dust particles. LOAC data could generally be fitted by a 3-mode lognormal distribution at roughly 0.2, 4 and 30 µm in modal diameter. Up to about 10-4 dust particles larger than 40 µm per cm3 are reported and no significant evolution of the size distribution was observed during the flights. The presence of such a coarse mode several days after dust emission is unexpected due to gravitational sedimentation. An indirect evidence of the presence of charged particles has been derived from the LOAC measurements and we speculate that electrical forces might counteract gravitational settling of the coarse particles.

Operational prediction of air quality for the United States: applications of satellite observations

NASA Astrophysics Data System (ADS)

Stajner, Ivanka; Lee, Pius; Tong, Daniel; Pan, Li; McQueen, Jeff; Huang, Jianping; Huang, Ho-Chun; Draxler, Roland; Kondragunta, Shobha; Upadhayay, Sikchya

2015-04-01

Operational predictions of ozone and wildfire smoke over United States (U.S.) and predictions of airborne dust over the contiguous 48 states are provided by NOAA at http://airquality.weather.gov/. North American Mesoscale (NAM) weather predictions with inventory based emissions estimates from the U.S. Environmental Protection Agency (EPA) and chemical processes within the Community Multiscale Air Quality (CMAQ) model are combined together to produce ozone predictions. Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model is used to predict wildfire smoke and dust storm predictions. Routine verification of ozone predictions relies on AIRNow compilation of observations from surface monitors. Retrievals of smoke column integrals from GOES satellites and dust column integrals from MODIS satellite instruments are used for verification of smoke and dust predictions. Recent updates of NOAA's operational air quality predictions have focused on mobile emissions using the projections of mobile sources for 2012. Since emission inventories are complex and take years to assemble and evaluate causing a lag of information, we recently began combing inventory information with projections of mobile sources. In order to evaluate this emission update, these changes in projected NOx emissions from 2005-2012 were compared with observed changes in Ozone Monitoring Instrument (OMI) NO2 observations and NOx measured by surface monitors over large U.S. cities over the same period. Comparisons indicate that projected decreases in NOx emissions from 2005 to 2012 are similar, but not as strong as the decreases in the observed NOx concentrations and in OMI NO2 retrievals. Nevertheless, the use of projected mobile NOx emissions in the predictions reduced biases in predicted NOx concentrations, with the largest improvement in the urban areas. Ozone biases are reduced as well, with the largest improvement seen in rural areas. Recent testing of PM2.5 predictions is relying on emissions inventories augmented by real time sources from wildfires and dust storms. The evaluation of these test predictions relies on surface monitor data, but efforts are in progress to include comparisons with satellite observed aerosol optical depth (AOD) products. Testing of PM2.5 predictions continues to exhibit seasonal biases: overprediction in the winter and underprediction in the summer. The current efforts focus on bias correction and development of linkages with global atmospheric composition predictions.

Web technologies for rapid assessment of pollution of the atmosphere of the industrial city

NASA Astrophysics Data System (ADS)

Shaparev, N.; Tokarev, A.; Yakubailik, O.; Soldatov, A.

2018-05-01

The functionality, architectural features, the user interface of the geoinformation web-system of environmental monitoring of Krasnoyarsk is discussed. This system is created in service-oriented architecture. Data collection from the automated stations to monitor the state of atmospheric air has been implemented. An original device to measure the level of contamination of the atmosphere by fine dust PM2.5 has developed. Assessment of the level of air pollution is based on the quality index AQI atmosphere.

Identification of dust outbreaks on infrared MSG-SEVIRI data by using a Robust Satellite Technique (RST)

NASA Astrophysics Data System (ADS)

Sannazzaro, Filomena; Filizzola, Carolina; Marchese, Francesco; Corrado, Rosita; Paciello, Rossana; Mazzeo, Giuseppe; Pergola, Nicola; Tramutoli, Valerio

2014-01-01

Dust storms are meteorological phenomena of great interest for scientific community because of their potential impact on climate changes, for the risk that may pose to human health and due to other issues as desertification processes and reduction of the agricultural production. Satellite remote sensing, thanks to global coverage, high frequency of observation and low cost data, may highly contribute in monitoring these phenomena, provided that proper detection methods are used. In this work, the known Robust Satellite Techniques (RST) multitemporal approach, used for studying and monitoring several natural/environmental hazards, is tested on some important dust events affecting Mediterranean region in May 2004 and Arabian Peninsula in February 2008. To perform this study, data provided by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) have been processed, comparing the generated dust maps to some independent satellite-based aerosol products. Outcomes of this work show that the RST technique can be profitably used for detecting dust outbreaks from space, providing information also about areas characterized by a different probability of dust presence. They encourage further improvements of this technique in view of its possible implementation in the framework of operational warning systems.

A Characterization of the Hot Infrared Background: The Infrared Cirrus, Zodiacal Dust Bands, and Solar System Dust Trails

DTIC Science & Technology

1991-04-01

AD-A239 132 PL -TR-91-2065 A CHARACTERIZATION OF THE HOT INFRARED BACKGROUND: THE INFRARED CIRRUS, ZODIACAL DUST BANDS, AND SOLAR SYSTEM DUST TRAILS F...addressee is no longer employed by your organization, please notify OL-AA PL /IMA, Hanscom AFB, MA 01731. This will assist us in maintaining a current...DECLASSIFICATION /DOWNGRADING SCHEDULE Distribution unlimited 4 PERFORMING ORGANIZATION REPORT NUMBER(S) S MONITORING ORGANIZATION REPORT NUMBER(S) PL -TR-91-2065 6a

Thermal tides in the dusty martian atmosphere: a verification of theory.

PubMed

Zurek, R W; Leovy, C B

1981-07-24

Major features of the daily surface pressure oscillations observed by the Viking landers during the two great dust storms on Mars in 1977 can be explained in terms of the classical atmospheric tidal theory developed for the earth's atmosphere. The most dramatic exception is the virtual disappearance of only the diurnal tide at Viking Lander 1 just before the second storm. This disappearance is attributed to destructive interference between the usually westward-traveling tide and an eastward-traveling diurnal Kelvin mode generated by orographically induced differential heating. The continuing Viking Lander 1 pressure measurements can be used with the model to monitor future great dust storms.

Development, application, and results of routine monitoring of Marek's disease virus in broiler house dust using real-time quantitative PCR.

PubMed

Walkden-Brown, Stephen W; Islam, A F Aminul; Groves, Peter J; Rubite, Ambrosio; Sharpe, Sue M; Burgess, Susan K

2013-06-01

Results are presented from four studies between 2002 and 2011 into the feasibility of routinely monitoring Marek's disease virus serotype 1 (MDV-1) in broiler house dust using real-time quantitative PCR (qPCR) measurement. Study 1 on two farms showed that detection of MDV-1 occurred earlier on average in dust samples tested using qPCR than standard PCR and in spleen samples from five birds per shed assayed for MDV-1 by qPCR or standard PCR. DNA quality following extraction from dust had no effect on detection of MDV-1. Study 2 demonstrated that herpesvirus of turkeys (HVT) and MDV serotype 2 (MDV-2) in addition to MDV-1 could be readily amplified from commercial farm dust samples, often in mixtures. MDV-2 was detected in 11 of 20 samples despite the absence of vaccination with this serotype. Study 3 investigated the reproducibility and sensitivity of the qPCR test and the presence of inhibitors in the samples. Samples extracted and amplified in triplicate showed a high level of reproducibility except at very low levels of virus near the limit of detection. Mixing of samples prior to extraction provided results consistent with the proportions in the mixture. Tests for inhibition showed that if the template contained DNA in the range 0.5-20 ng/microl no inhibition of the reaction was detectable. The sensitivity of the tests in terms of viral copy number (VCN) per milligram of dust was calculated to be in the range 24-600 VCN/mg for MDV-1, 48-1200 VCN/mg for MDV-2, and 182-4560 VCN/mg for HVT. In study 4 the results of 1976 commercial tests carried out for one company were analyzed. Overall 23.1% of samples were positive for MDV-1, 26.1% in unvaccinated and 16.4% in vaccinated chickens. There was marked regional and temporal variation in the proportion of positive samples and the MDV-1 load. The tests were useful in formulating Marek's disease vaccination strategies. The number of samples submitted has increased recently, as has the incidence of positive samples. These studies provide strong evidence that detection and quantitation of MDV-1, HVT, and MDV-2 in poultry house dust using qPCR is robust, sensitive, reproducible, and meaningful, both biologically and commercially. Tactical vaccination based on monitoring of MDV-1 rather than routine vaccination may reduce selection pressure for increased virulence in MDV-1.

The Distribution of Interplanetary Dust Near 1-AU: An MMS Perspective

NASA Astrophysics Data System (ADS)

Adrian, M. L.; St Cyr, O. C.; Wilson, L. B., III; Schiff, C.; Sacks, L. W.; Chai, D. J.; Queen, S. Z.; Sedlak, J. E.

2017-12-01

The distribution of dust in the ecliptic plane in the vicinity of 1-AU has been inferred from impacts on the four Magnetospheric Multiscale (MMS) mission spacecraft as detected by the Acceleration Measurement System (AMS) during periods when no other spacecraft activities are in progress. Consisting of four identically instrumented spacecraft, with an inter-spacecraft separation ranging from 10-km to 400-km, the MMS constellation forms a dust "detector" with approximately four-times the collection area of any previous dust monitoring framework. Here we introduce the MMS-AMS and the inferred dust impact observations, provide a preliminary comparison of the MMS distribution of dust impacts to previously reported interplanetary dust distributions — namely those of the STEREO mission — and report on our initial comparison of the MMS distribution of dust impacts with known meteor showers.

Reducing uncertainty in dust monitoring to detect aeolian sediment transport responses to land cover change

NASA Astrophysics Data System (ADS)

Webb, N.; Chappell, A.; Van Zee, J.; Toledo, D.; Duniway, M.; Billings, B.; Tedela, N.

2017-12-01

Anthropogenic land use and land cover change (LULCC) influence global rates of wind erosion and dust emission, yet our understanding of the magnitude of the responses remains poor. Field measurements and monitoring provide essential data to resolve aeolian sediment transport patterns and assess the impacts of human land use and management intensity. Data collected in the field are also required for dust model calibration and testing, as models have become the primary tool for assessing LULCC-dust cycle interactions. However, there is considerable uncertainty in estimates of dust emission due to the spatial variability of sediment transport. Field sampling designs are currently rudimentary and considerable opportunities are available to reduce the uncertainty. Establishing the minimum detectable change is critical for measuring spatial and temporal patterns of sediment transport, detecting potential impacts of LULCC and land management, and for quantifying the uncertainty of dust model estimates. Here, we evaluate the effectiveness of common sampling designs (e.g., simple random sampling, systematic sampling) used to measure and monitor aeolian sediment transport rates. Using data from the US National Wind Erosion Research Network across diverse rangeland and cropland cover types, we demonstrate how only large changes in sediment mass flux (of the order 200% to 800%) can be detected when small sample sizes are used, crude sampling designs are implemented, or when the spatial variation is large. We then show how statistical rigour and the straightforward application of a sampling design can reduce the uncertainty and detect change in sediment transport over time and between land use and land cover types.

Silica dust exposure: Effect of filter size to compliance determination

NASA Astrophysics Data System (ADS)

Amran, Suhaily; Latif, Mohd Talib; Khan, Md Firoz; Leman, Abdul Mutalib; Goh, Eric; Jaafar, Shoffian Amin

2016-11-01

Monitoring of respirable dust was performed using a set of integrated sampling system consisting of sampling pump attached with filter media and separating device such as cyclone or special cassette. Based on selected method, filter sizes are either 25 mm or 37 mm poly vinyl chloride (PVC) filter. The aim of this study was to compare performance of two types of filter during personal respirable dust sampling for silica dust under field condition. The comparison strategy focused on the final compliance judgment based on both dataset. Eight hour parallel sampling of personal respirable dust exposure was performed among 30 crusher operators at six quarries. Each crusher operator was attached with parallel set of integrated sampling train containing either 25 mm or 37 mm PVC filter. Each set consisted of standard flow SKC sampler, attached with SKC GS3 cyclone and 2 pieces cassette loaded with 5.0 µm of PVC filter. Samples were analyzed by gravimetric technique. Personal respirable dust exposure between the two types of filters indicated significant positive correlation (p < 0.05) with moderate relationship (r2 = 0.6431). Personal exposure based on 25 mm PVC filter indicated 0.1% non-compliance to overall data while 37 mm PVC filter indicated similar findings at 0.4 %. Both data showed similar arithmetic mean(AM) and geometric mean(GM). In overall we concluded that personal respirable dust exposure either based on 25mm or 37mm PVC filter will give similar compliance determination. Both filters are reliable to be used in respirable dust monitoring for silica dust related exposure.

Dust storm from Syria- a potential new aerosol source in the E. Mediterranean- A ceilometer and synoptic study

NASA Astrophysics Data System (ADS)

Alpert, Pinhas; Egert, Smadar; Uzan, Leenes

2017-04-01

On 7 Sep 2015 an unprecedented huge dust plume approached the SE Mediterranean basin from the northeast- Syria region. According to the Israeli meteorological service it is the first time in 75 years of measurements, that a dust storm reaches Israel early September, lasts several days and dust concentrations reach values 100 times the normal (1700µg/m3). Dust storms are normally monitored in the east Mediterranean using satellites and surface PM data. Obviously, these cannot show the vertical evolution of the dust including penetration, sinking and cleaning since vertical profiles are not available. High-resolution, micro Lidar Ceilometer network is gradually established in Israel. A few instruments of this network were already operational during the dust storm. The most crucial vertical information, monitored by these Ceilometers with 10m resolution vertically, every 16s, is analyzed. The difference in the cloud-layers allow the investigation of the high altitude of 1000m dust penetration, its sinking into the complex structured 250-500m mixed layer and the gradual 3D cleaning. This finding contradicts the conventional understanding that cleaning is due to gradual descent and shows not only the vertical fluctuation during the entire event but also the vertical rise to 2000m at the end of the event. The vertical information showed that the actual event period duration was 7 days, compared to only 90 hours based on traditional detectors. Is it a new dust source in the E. Mediterranean-long and short term trends?

A Methodology to Monitor Airborne PM10 Dust Particles Using a Small Unmanned Aerial Vehicle

PubMed Central

Alvarado, Miguel; Gonzalez, Felipe; Erskine, Peter; Cliff, David; Heuff, Darlene

2017-01-01

Throughout the process of coal extraction from surface mines, gases and particles are emitted in the form of fugitive emissions by activities such as hauling, blasting and transportation. As these emissions are diffuse in nature, estimations based upon emission factors and dispersion/advection equations need to be measured directly from the atmosphere. This paper expands upon previous research undertaken to develop a relative methodology to monitor PM10 dust particles produced by mining activities making use of small unmanned aerial vehicles (UAVs). A module sensor using a laser particle counter (OPC-N2 from Alphasense, Great Notley, Essex, UK) was tested. An aerodynamic flow experiment was undertaken to determine the position and length of a sampling probe of the sensing module. Flight tests were conducted in order to demonstrate that the sensor provided data which could be used to calculate the emission rate of a source. Emission rates are a critical variable for further predictive dispersion estimates. First, data collected by the airborne module was verified using a 5.0 m tower in which a TSI DRX 8533 (reference dust monitoring device, TSI, Shoreview, MN, USA) and a duplicate of the module sensor were installed. Second, concentration values collected by the monitoring module attached to the UAV (airborne module) obtaining a percentage error of 1.1%. Finally, emission rates from the source were calculated, with airborne data, obtaining errors as low as 1.2%. These errors are low and indicate that the readings collected with the airborne module are comparable to the TSI DRX and could be used to obtain specific emission factors from fugitive emissions for industrial activities. PMID:28216557

Atmospheric Pressure Patterns Before and During Dust Storm

NASA Image and Video Library

2012-11-27

This graph compares a typical daily pattern of changing atmospheric pressure blue with the pattern during a regional dust storm hundreds of miles away red. The data are by the Rover Environmental Monitoring Station REMS on NASA Curiosity rover.

High-resolution real-time optical studies of radiological air sample filtration processes in an environmental continuous air monitor

NASA Astrophysics Data System (ADS)

Rodgers, John C.; Wasiolek, Piotr T.; Schery, Stephen D.; Alcantara, Raul E.

1999-01-01

The need for a continuous air monitor capable of quick and accurate measurements of airborne radioactivity in close proximity to the work environment during waste management, site restoration, and D&D operations led to the Los Alamos National Laboratory development of an environmental continuous air monitor (ECAM). Monitoring the hostile work environment of waste recovery, for example, presents unique challenges for detector design for detectors previously used for the clean room conditions of the typical plutonium laboratory. The environmental and atmospheric conditions (dust, high wind, etc.) influence aerosol particle penetration into the ECAM sampling head as well as the build-up of deposits on the ECAM filter.

Dust Storm Monitoring Using Satellite Observatory and Numerical Modeling Analysis

NASA Astrophysics Data System (ADS)

Taghavi, Farahnaz

In recent years, the frequency of dust pollution events in the Iran Southwest are increased which caused huge damage and imposed a negative impacts on air quality, airport traffic and people daily life in local areas. Dust storms in this area usually start with the formation of a low-pressure center over the Arabian Peninsula. The main objectives of this study is to asses and monitor the movement of aerosols and pollutions from origin source to local areas using satellite imagery and numerical modeling analysis. Observational analyses from NCEP such as synoptic data (Uwind,Vwind,Vorticity and Divergence Fields), upper air radiosonde, measured visibility distributions, land cover data are also used in model comparisons to show differences in occurrence of dust events. The evolution and dynamics of this phenomena are studied on the based a method to modify the initial state of NWP output using discrepancies between dynamic fields and WV imagery in a grid. Results show that satellite images offers a means to control the behavior of numeric models and also the model using land cover data improving the wind-blown dust modeling.

Case Report: Lung Disease in World Trade Center Responders Exposed to Dust and Smoke: Carbon Nanotubes Found in the Lungs of World Trade Center Patients and Dust Samples

PubMed Central

Wu, Maoxin; Gordon, Ronald E.; Herbert, Robin; Padilla, Maria; Moline, Jacqueline; Mendelson, David; Litle, Virginia; Travis, William D.; Gil, Joan

2010-01-01

Context After the collapse of the World Trade Center (WTC) on 11 September 2001, a dense cloud of dust containing high levels of airborne pollutants covered Manhattan and parts of Brooklyn, New York. Between 60,000 and 70,000 responders were exposed. Many reported adverse health effects. Case presentation In this report we describe clinical, pathologic, and mineralogic findings in seven previously healthy responders who were exposed to WTC dust on either 11 September or 12 September 2001, who developed severe respiratory impairment or unexplained radiologic findings and underwent video-assisted thoracoscopic surgical lung biopsy procedures at Mount Sinai Medical Center. WTC dust samples were also examined. We found that three of the seven responders had severe or moderate restrictive disease clinically. Histopathology showed interstitial lung disease consistent with small airways disease, bronchiolocentric parenchymal disease, and nonnecrotizing granulomatous condition. Tissue mineralogic analyses showed variable amounts of sheets of aluminum and magnesium silicates, chrysotile asbestos, calcium phosphate, and calcium sulfate. Small shards of glass containing mostly silica and magnesium were also found. Carbon nanotubes (CNT) of various sizes and lengths were noted. CNT were also identified in four of seven WTC dust samples. Discussion These findings confirm the previously reported association between WTC dust exposure and bronchiolar and interstitial lung disease. Long-term monitoring of responders will be needed to elucidate the full extent of this problem. The finding of CNT in both WTC dust and lung tissues is unexpected and requires further study. PMID:20368128

Electrical Charging Hazards Originating from the Surface (ECHOS): Understanding the Martian Electro-Meteorological Environment

NASA Technical Reports Server (NTRS)

Farrell, W. M.; Desch, M. D.; Marshall, J. R.; Delory, G. T.; Kolecki, J. C.; Hillard, G. B.; Kaiser, M. L.; Haberle, R. M.; Zent, A. P.; Luhmann, J. G.

2000-01-01

In 1999, the NASA/Human Exploration and Development of Space (HEDS) enterprise selected a number of payloads to fly to the Martian surface in an 03 opportunity (prior to the MPL loss). Part of a proposed experiment, ECHOS, was selected to specifically understand the electrical charging hazards from tribocharged dust in the ambient atmosphere, in dust devils, and in larger storms. It is expected that Martian dust storms become tribocharged much like terrestrial dust devils which can possess almost a million elementary charges per cubic centimeter. The ECHOS package features a set of instruments for measuring electric effects: a radio to detect AC electric fields radiating from discharges in the storm,a DC electric field system for sensing electrostatic fields from concentrations of charged dust grains, and a lander electrometer chain for determining the induced potential on its body and MAV (Mars Ascent Vehicle) during the passages of a charged dust storm. Given that electricity is a systemic process originating from wind-blown dust, we also proposed to correlate the electrical measurements with fundamental fluid/meteorological observations, including wind velocity and vorticity, temperature, and pressure. Triboelectricity will also affect local chemistry, and chemical-sensing devices were also considered a feature of the package. The primary HEDS objectives of the ECHOS sensing suite is to discover and monitor the natural electrical hazards associated with dust devils and storms, and determine their enviro-effectiveness on human systems. However, ECHOS also has a strong footprint in the overarching science objectives of the Mars Surveyor Program.

WMO SDS-WAS NAMEE Regional Center: Towards continuous evaluation of dust models in Northern Africa

NASA Astrophysics Data System (ADS)

Basart, Sara; García-Castillo, Gerardo; Cuevas, Emilio; Terradellas, Enric

2016-04-01

One of the most important activities of the Regional Center for Northern Africa, Middle East and Europe of the World Meteorological Organization's Sand and Dust Storm Warning Advisory and Assessment System (WMO SDS-WAS, http://sds-was.aemet.es) is the dust model intercomparison and forecast evaluation, which is deemed an indispensable service to the users and an invaluable tool to assess model skills. Currently, the Regional Center collects daily dust forecasts from models run by nine partners (BSC, ECMWF, NASA, NCEP, SEEVCCC, EMA, CNR-ISAC, NOA and UK Met Office). A multi-model ensemble has also been set up in an effort to provide added-value products to the users. The first problem to address the dust model evaluation is the scarcity of suitable routine observations near the Sahara, the world's largest source of mineral dust. The present contribution presents preliminary results of dust model evaluation using new observational datasets. The current routine evaluation of dust predictions is focused on total-column dust optical depth (DOD) and uses remote-sensing retrievals from sun-photometric (AERONET) and satellite (MODIS) measurements. However, most users of dust forecasts are interested in the concentration near the surface (in the air we breathe) rather than in the total column content. Therefore, evaluation of the predicted surface concentration is also necessary. In this context, the initiative of the African Monsoon Interdisciplinary Analysis (AMMA) International Program to establish permanent measuring stations in the Sahel is extremely important. Tapered Element Oscillating Microbalance (TEOM) monitors continuously record PM10 in M'Bour (Senegal); Cinzana (Mali) and Banizoumbou (Niger). This surface model evaluation is complemented with the PM10 observation from the Air Quality Control and Monitoring Network (AQCMN) of the Canary Islands (Spain). The region, located in the sub-tropical Eastern Atlantic (roughly 100 km west of the Moroccan coast), is frequently affected by intrusions of Saharan dust. Regional Node are evaluated during two years (2013-2014) with observations recorded in the Sahelian region and Canary Islands. Additionally, since the data sets of weather records have an excellent spatial and temporal coverage, observations of horizontal visibility included in meteorological reports are used as an alternative way to monitor dust events in near-real-time (NRT). Recently, a new visibility product that includes more than 1,500 METAR stations has implemented in the SDS-WAS NAMEE Regional Center. The present contribution also will demonstrate how the visibility can complement the information provided by other observing systems (air quality monitoring stations, sun photometers, vertical profilers or satellite products) and numerical simulations presenting its application in tracking several dust episodes. Otherwise, the vertical distribution of aerosol also influences the radiative effect at the top of the atmosphere, especially when aerosols have strong absorption of shortwave radiation. The free troposphere contribution to aerosol optical depth (AOD) and the altitude of lofted layers are provided thanks to the vertical profiling capability of the lidar/ceilomenter technique. Currently, a lidar located in Dakar (Senegal) and a ceilometer in Santa Cruz de Tenerife (Canary Islands, Spain) provide near-real-time (NRT) vertical profiles of aerosols, which are compared with those simulated by models.

Development of a dust deposition forecast model for a mine tailings impoundment

NASA Astrophysics Data System (ADS)

Stovern, Michael

Wind erosion, transport and deposition of particulate matter can have significant impacts on the environment. It is observed that about 40% of the global land area and 30% of the earth's population lives in semiarid environments which are especially susceptible to wind erosion and airborne transport of contaminants. With the increased desertification caused by land use changes, anthropogenic activities and projected climate change impacts windblown dust will likely become more significant. An important anthropogenic source of windblown dust in this region is associated with mining operations including tailings impoundments. Tailings are especially susceptible to erosion due to their fine grain composition, lack of vegetative coverage and high height compared to the surrounding topography. This study is focused on emissions, dispersion and deposition of windblown dust from the Iron King mine tailings in Dewey-Humboldt, Arizona, a Superfund site. The tailings impoundment is heavily contaminated with lead and arsenic and is located directly adjacent to the town of Dewey-Humboldt. The study includes in situ field measurements, computational fluid dynamic modeling and the development of a windblown dust deposition forecasting model that predicts deposition patterns of dust originating from the tailings impoundment. Two instrumented eddy flux towers were setup on the tailings impoundment to monitor the aeolian and meteorological conditions. The in situ observations were used in conjunction with a computational fluid dynamic (CFD) model to simulate the transport of windblown dust from the mine tailings to the surrounding region. The CFD model simulations include gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport was used to track the trajectories of larger particles and to monitor their deposition locations. The CFD simulations were used to estimate deposition of tailings dust and identify topographic mechanisms that influence deposition. Simulation results indicated that particles preferentially deposit in regions of topographic upslope. In addition, turbulent wind fields enhanced deposition in the wake region downwind of the tailings. This study also describes a deposition forecasting model (DFM) that can be used to forecast the transport and deposition of windblown dust originating from a mine tailings impoundment. The DFM uses in situ observations from the tailings and theoretical simulations of aerosol transport to parameterize the model. The model was verified through the use of inverted-disc deposition samplers. The deposition forecasting model was initialized using data from an operational Weather Research and Forecasting (WRF) model and the forecast deposition patterns were compared to the inverted-disc samples through gravimetric, chemical composition and lead isotopic analysis. The DFM was verified over several month-long observing periods by comparing transects of arsenic and lead tracers measured by the samplers to the DFM PM27 forecast. Results from the sampling periods indicated that the DFM was able to accurately capture the regional deposition patterns of the tailings dust up to 1 km. Lead isotopes were used for source apportionment and showed spatial patterns consistent with the DFM and the observed weather conditions. By providing reasonably accurate estimates of contaminant deposition rates, the DFM can improve the assessment of human health impacts caused by windblown dust from the Iron King tailings impoundment.

Desert Dust Properties, Modelling, and Monitoring

NASA Technical Reports Server (NTRS)

Kaskaoutis, Dimitris G.; Kahn, Ralph A.; Gupta, Pawan; Jayaraman, Achuthan; Bartzokas, Aristides

2013-01-01

This paper is just the three-page introduction to a Special Issue of Advances in Meteorology focusing on desert dust. It provides a paragraph each on 13 accepted papers, most relating to the used of satellite data to assess attributes or distribution of airborne desert dust. As guest Associate Editors of this issue, we organized the papers into a systematic whole, beginning with large-scale transport and seasonal behavior, then to regional dust transport, transport history, and climate impacts, first in the Mediterranean region, then India and central Asia, and finally focusing on transport model assessment and the use of lidar as a technique to constrain dust spatial-temporal distribution.

Asian dust events of April 1998

USGS Publications Warehouse

Husar, R.B.; Tratt, D.M.; Schichtel, B.A.; Falke, S.R.; Li, F.; Jaffe, D.; Gasso, S.; Gill, T.; Laulainen, N.S.; Lu, F.; Reheis, M.C.; Chun, Y.; Westphal, D.; Holben, B.N.; Gueymard, C.; McKendry, I.; Kuring, N.; Feldman, G.C.; McClain, C.; Frouin, R.J.; Merrill, J.; DuBois, D.; Vignola, F.; Murayama, T.; Nickovic, S.; Wilson, W.E.; Sassen, K.; Sugimoto, N.; Malm, W.C.

2001-01-01

On April 15 and 19, 1998, two intense dust storms were generated over the Gobi desert by springtime low-pressure systems descending from the northwest. The windblown dust was detected and its evolution followed by its yellow color on SeaWiFS satellite images, routine surface-based monitoring, and through serendipitous observations. The April 15 dust cloud was recirculating, and it was removed by a precipitating weather system over east Asia. The April 19 dust cloud crossed the Pacific Ocean in 5 days, subsided to the surface along the mountain ranges between British Columbia and California, and impacted severely the optical and the concentration environments of the region. In east Asia the dust clouds increased the albedo over the cloudless ocean and land by up to 10-20%, but it reduced the near-UV cloud reflectance, causing a yellow coloration of all surfaces. The yellow colored backscattering by the dust eludes a plausible explanation using simple Mie theory with constant refractive index. Over the West Coast the dust layer has increased the spectrally uniform optical depth to about 0.4, reduced the direct solar radiation by 30-40%, doubled the diffuse radiation, and caused a whitish discoloration of the blue sky. On April 29 the average excess surface-level dust aerosol concentration over the valleys of the West Coast was about 20-50 ??g/m3 with local peaks >100 ??g/m3. The dust mass mean diameter was 2-3 ??m, and the dust chemical fingerprints were evident throughout the West Coast and extended to Minnesota. The April 1998 dust event has impacted the surface aerosol concentration 2-4 times more than any other dust event since 1988. The dust events were observed and interpreted by an ad hoc international web-based virtual community. It would be useful to set up a community-supported web-based infrastructure to monitor the global aerosol pattern for such extreme aerosol events, to alert and to inform the interested communities, and to facilitate collaborative analysis for improved air quality and disaster management. Copyright 2001 by the American Geophysical Union.

Calipso recordings and monitoring dust storms over the open seas in south of the iran plateau

NASA Astrophysics Data System (ADS)

Khalesifard, Hamid R.; Bayat, Farizeh

2018-04-01

Open seas in the south of the Iran plateau are under the influence of heavy dust storms which are originating either from the Tigris and Euphrates basin, the Arabian Peninsula or Hamoun lake. We have used the recordings of the CALIPSO satellite to investigate the seasonal variations as well as the origins of the dust storms over the region. CALIPSO data set shows dust activities are frequent during May to September in the interested region and the Hamoun lake has considerable impacts on it.

Fiber-coupled LED gas sensor and its application to online monitoring of ecoefficient dielectric insulation gases in high-voltage circuit breakers.

PubMed

Kramer, Axel; Over, Daniel; Stoller, Patrick; Paul, Thomas A

2017-05-20

Novel dielectric insulation gases used as alternatives to sulfur hexafluoride in gas-insulated switchgear (GIS) include several mixtures containing fluorinated organic compounds. We developed a fiber-optic analyzer enabling concentration measurement of fluoroketones used in medium- and high-voltage switchgear applications by ABB, with concurrent compensation of disturbing effects caused by dust and dirt. The sensor enables measurements in GIS and even in operating high-voltage circuit breakers. The online availability of concentration readings of fluoroketones is important for development tests, but can also be applied for monitoring or diagnostics of field installations.

African dust contribution to mean ambient PM10 across the Mediterranean Basin: A quantitative approach to investigate spatial and seasonal patterns

NASA Astrophysics Data System (ADS)

Querol, X.; Pandolfi, M.; Pey, J.; Alastuey, A.; Cusack, M.; Pérez, N.; Amato, F.; Moreno, T.; Viana, M.; Mihalopoulos, N.

2009-04-01

The aim of the present study is quantifying African dust contributions to mean PM10 levels recorded across the Mediterranean basin (2001-2008, 1995-2008 in one case) and evidencing spatial variations and seasonal trends. To this end the same methodology has been applied to a number of data sets on PM levels recorded in aerosol research monitoring sites (Montseny-EUSAAR, Spain, Finokalia-EUSAAR, Greece) and from a number of regional background (RB) monitoring sites from the Co-operative Program for Monitoring and Evaluation of the Long-Range Transmission of Air pollutants in Europe (EMEP) and regional air quality monitoring networks available from Airbase-EEA data set. Around 20 data series spread across the whole Mediterranean and bordering regions have been selected and analyzed in the present study. Once the PM data were obtained the days under the influence of African dust outbreaks were identified (using HYSPLIT, DREAM-BSC, SKIRON and NAAPS tools) for each receptor site. Subsequently, a method (Escudero et al., 2007) based on the statistical data treatment of time series of PM levels, without a need of chemical analysis, was used for the quantification of the daily African PM load during dust outbreaks at each site. Finally, PM speciation data available at MSY and FKL were used to differentiate the local/regional from the African mineral contributions across the Mediterranean Basin. Results show a clear W to E and N to S increasing gradients, both on annual PM levels and annual African dust load. In the Eastern Mediterranean the episodes are more intense and are relatively frequent in spring and summer period. However in the western side of the basin, African dust outbreaks are more frequent in summer and winter. In the N, NW and NE sides of the basin 1-2 µgPM10/m3 of mean annual dust contribution was quantified, whereas in the S, SE, SW this annual contribution ranges from 6 to 10 µgPM10/m3. The number of exceedances of the PM10 daily limit value attributable to the African dust contributions was also evaluated fro the whole Mediterranean. Comparison of the African dust annual load with PM10 speciation allowed quantifying regional dust contributions. Thus, in urban areas we are able to discriminate the contribution of African, regional, urban and road dust. References Escudero M. et al., (2007). Atmos. Environ., 41, 5516- 5524. Acknowledgements This study was supported by the Ministry of Science and Innovation (CGL2005-03428-C04-03/CLI, CGL2007-62505/CLI, GRACCIE- CSD2007-00067), the European Union (6th framework CIRCE IP, 036961, EUSAAR RII3-CT-2006-026140). Finally, we would like to express our gratitude to Airbase-EEA for allowing free access to ambient PM levels recorded at a large number of sites in Europe.

Dust emission: small-scale processes with global consequences

USGS Publications Warehouse

Okin, Gregory S.; Bullard, Joanna E.; Reynolds, Richard L.; Ballantine, John-Andrew C.; Schepanski, Kerstin; Todd, Martin C.; Belnap, Jayne; Baddock, Matthew C.; Gill, Thomas E.; Miller, Mark E.

2011-01-01

Desert dust, both modern and ancient, is a critical component of the Earth system. Atmospheric dust has important effects on climate by changing the atmospheric radiation budget, while deposited dust influences biogeochemical cycles in the oceans and on land. Dust deposited on snow and ice decreases its albedo, allowing more light to be trapped at the surface, thus increasing the rate of melt and influencing energy budgets and river discharge. In the human realm, dust contributes to the transport of allergens and pathogens and when inhaled can cause or aggravate respiratory diseases. Dust storms also represent a significant hazard to road and air travel. Because it affects so many Earth processes, dust is studied from a variety of perspectives and at multiple scales, with various disciplines examining emissions for different purposes using disparate strategies. Thus, the range of objectives in studying dust, as well as experimental approaches and results, has not yet been systematically integrated. Key research questions surrounding the production and sources of dust could benefit from improved collaboration among different research communities. These questions involve the origins of dust, factors that influence dust production and emission, and methods through which dust can be monitored.

Dust: Small-scale processes with global consequences

USGS Publications Warehouse

Okin, G.S.; Bullard, J.E.; Reynolds, R.L.; Ballantine, J.-A.C.; Schepanski, K.; Todd, M.C.; Belnap, J.; Baddock, M.C.; Gill, T.E.; Miller, M.E.

2011-01-01

Desert dust, both modern and ancient, is a critical component of the Earth system. Atmospheric dust has important effects on climate by changing the atmospheric radiation budget, while deposited dust influences biogeochemical cycles in the oceans and on land. Dust deposited on snow and ice decreases its albedo, allowing more light to be trapped at the surface, thus increasing the rate of melt and influencing energy budgets and river discharge. In the human realm, dust contributes to the transport of allergens and pathogens and when inhaled can cause or aggravate respiratory diseases. Dust storms also represent a significant hazard to road and air travel. Because it affects so many Earth processes, dust is studied from a variety of perspectives and at multiple scales, with various disciplines examining emissions for different purposes using disparate strategies. Thus, the range of objectives in studying dust, as well as experimental approaches and results, has not yet been systematically integrated. Key research questions surrounding the production and sources of dust could benefit from improved collaboration among different research communities. These questions involve the origins of dust, factors that influence dust production and emission, and methods through which dust can be monitored. ?? Author(s) 2011.

Simulated Pitot tube designed to detect blockage by ice, volcanic dust, sand, insects and to clear it: phase 1

NASA Astrophysics Data System (ADS)

Jackson, David A.

2014-05-01

A simulated coaxial Pitot tube has been developed using fibre optic sensors combined with actuators to monitor and maintain its correct operation under different environmental conditions. Experiments are reported showing that the dynamic and static tubes can be cleared of ice. It is also demonstrated that the dynamic tube can be cleared of dust and sand which is not the case for the static tube in the coaxial configuration. An approach is proposed to overcome this problem involving a conventional configuration where the static tube is operated independently orthogonal to the dynamic tube with a second set of sensors and actuators.

Assessment of respirable dust and its free silica contents in different Indian coalmines.

PubMed

Mukherjee, Ashit K; Bhattacharya, Sanat K; Saiyed, Habibullah N

2005-04-01

Assessment of respirable dust, personal exposures of miners and free silica contents in dust were undertaken to find out the associated risk of coal workers' pneumoconiosis in 9 coal mines of Eastern India during 1988-91. Mine Research Establishment (MRE), 113A Gravimetric Dust Sampler (GDS) and personal samplers (AFC 123), Cassella, London, approved by Director General of Mines Safety (DGMS) were used respectively for monitoring of mine air dust and personal exposures of miners. Fourier Transform Infra-red (FTIR) Spectroscopy determined free silica in respirable dusts. Thermal Conditions like Wet Bulb Globe Temperature (WBGT) index, humidity and wind velocity were also recorded during monitoring. The dust levels in the face return air of both, Board & Pillar (B&P) and Long Wall (LW) mining were found above the permissible level recommended by DGMS, Govt. of India. The drilling, blasting and loading are the major dusty operations in B&P method. Exposures of driller and loader were varied between, 0.81-9.48 mg/m3 and 0.05-9.84 mg/m3 respectively in B&P mining, whereas exposures of DOSCO loader, Shearer operator and Power Support Face Worker were varied between 2.65-9.11 mg/m3, 0.22-10.00 mg/m3 and 0.12-9.32 mg/m3 respectively in LW mining. In open cast mining, compressor and driller operators are the major exposed groups. The percentage silica in respirable dusts found below 5% in all most all the workers except among query loaders and drillers of open cast mines.

Lunar Airborne Dust Toxicity Hazard Assessments (Invited)

NASA Astrophysics Data System (ADS)

Cooper, B. L.; McKay, D. S.; Taylor, L. A.; Wallace, W. T.; James, J.; Riofrio, L.; Gonzalez, C. P.

2009-12-01

The Lunar Airborne Dust Toxicity Assessment Group (LADTAG) is developing data to set the permissible limits for human exposure to lunar dust. This standard will guide the design of airlocks and ports for EVA, as well as the requirements for filtering and monitoring the atmosphere in habitable vehicles, rovers and other modules. LADTAG’s recommendation for permissible exposure limits will be delivered to the Constellation Program in late 2010. The current worst-case exposure limit of 0.05 mg/m3, estimated by LADTAG in 2006, reflects the concern that lunar dust may be as toxic as quartz dust. Freshly-ground quartz is known to be more toxic than un-ground quartz dust. Our research has shown that the surfaces of lunar soil grains can be more readily activated by grinding than quartz. Activation was measured by the amount of free radicals generated—activated simulants generate Reactive Oxygen Species (ROS) i.e., production of hydroxyl free radicals. Of the various influences in the lunar environment, micrometeorite bombardment probably creates the most long-lasting reactivity on the surfaces of grains, although solar wind impingement and short-wavelength UV radiation also contribute. The comminution process creates fractured surfaces with unsatisfied bonds. When these grains are inhaled and carried into the lungs, they will react with lung surfactant and cells, potentially causing tissue damage and disease. Tests on lunar simulants have shown that dissolution and leaching of metals can occur when the grains are exposed to water—the primary component of lung fluid. However, simulants may behave differently than actual lunar soils. Rodent toxicity testing will be done using the respirable fraction of actual lunar soils (particles with physical size of less than 2.5 micrometers). We are currently separating the fine material from the coarser material that comprises >95% of the mass of each soil sample. Dry sieving is not practical in this size range, so a new system was developed for this task. The dust separation system includes a fluidized bed, an elutriation flask, and a cyclone. The product dust is collected on a membrane filter with 0.45 micrometer pore size. Collection and separation efficiencies, and particle size distribution measurements of the material retained in the various components are tracked as development and tests proceed. Calculations show that respirable-sized particles, if released in a habitat, would remain suspended in the air for extended periods of time. Without active dust control, most of this fine dust would end up in the crew’s lungs. Dust exposure standards, similar to those established for quartz on Earth, will determine the design, mass, power, and cost of dust control systems incorporated into lunar habitats and pressurized rovers.

75 FR 73995 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-30

... http://www.msha.gov/REGS/FEDREG/PROPOSED/2010PROP/2010-25249.pdf . The proposed rule would revise the.../PROPOSED/2010PROP/2010-25249.pdf . The following error in the preamble to the proposed rule is corrected to...

Studying the Fading Infrared Evolution of SN 1978K

NASA Astrophysics Data System (ADS)

Smith, Ian

2018-05-01

SN 1978K in the nearby barred spiral galaxy NGC 1313 is a remarkable Type IIn supernova that remains bright at X-ray through radio wavelengths 40 years after its explosion. Our long-term program of multi-wavelength observations is probing the dense medium that was ejected by the progenitor star, possibly a Luminous Blue Variable. Only SN 1978K was detected in a search for warm dust in supernovae in the transitional phase (age 10-100 years). Thus SN 1978K is a prime target for studying whether supernovae such as this are important contributors to the Universal dust budget and how the dust reacts to the strong and varying UV and X-ray emissions. Our analysis of the previous Spitzer observations shows a rapid fading of the warm dust emission. Here we request one Spitzer observation at 3.6 and 4.5 microns to continue to monitor the infrared evolution. This will serve as a bridge to future monitoring with JWST.

Estimating Children's Soil/Dust Ingestion Rates through Retrospective Analyses of Blood Lead Biomonitoring from the Bunker Hill Superfund Site in Idaho.

PubMed

von Lindern, Ian; Spalinger, Susan; Stifelman, Marc L; Stanek, Lindsay Wichers; Bartrem, Casey

2016-09-01

Soil/dust ingestion rates are important variables in assessing children's health risks in contaminated environments. Current estimates are based largely on soil tracer methodology, which is limited by analytical uncertainty, small sample size, and short study duration. The objective was to estimate site-specific soil/dust ingestion rates through reevaluation of the lead absorption dose-response relationship using new bioavailability data from the Bunker Hill Mining and Metallurgical Complex Superfund Site (BHSS) in Idaho, USA. The U.S. Environmental Protection Agency (EPA) in vitro bioavailability methodology was applied to archived BHSS soil and dust samples. Using age-specific biokinetic slope factors, we related bioavailable lead from these sources to children's blood lead levels (BLLs) monitored during cleanup from 1988 through 2002. Quantitative regression analyses and exposure assessment guidance were used to develop candidate soil/dust source partition scenarios estimating lead intake, allowing estimation of age-specific soil/dust ingestion rates. These ingestion rate and bioavailability estimates were simultaneously applied to the U.S. EPA Integrated Exposure Uptake Biokinetic Model for Lead in Children to determine those combinations best approximating observed BLLs. Absolute soil and house dust bioavailability averaged 33% (SD ± 4%) and 28% (SD ± 6%), respectively. Estimated BHSS age-specific soil/dust ingestion rates are 86-94 mg/day for 6-month- to 2-year-old children and 51-67 mg/day for 2- to 9-year-old children. Soil/dust ingestion rate estimates for 1- to 9-year-old children at the BHSS are lower than those commonly used in human health risk assessment. A substantial component of children's exposure comes from sources beyond the immediate home environment. von Lindern I, Spalinger S, Stifelman ML, Stanek LW, Bartrem C. 2016. Estimating children's soil/dust ingestion rates through retrospective analyses of blood lead biomonitoring from the Bunker Hill Superfund Site in Idaho. Environ Health Perspect 124:1462-1470; http://dx.doi.org/10.1289/ehp.1510144.

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.

Cycles of selected elements in the frame of Globalization and Global Change in the environment of Tenerife (Canary Islands, Spain)

NASA Astrophysics Data System (ADS)

Heidak, Markus O.; Glasmacher, Ulrich A.; Schöler, Heinfried; Trieloff, Mario; Kober, Bernd

2010-05-01

The Laurel Forest is an important and sensitive ecosystem with particular element cycling mechanisms. On Tenerife the distribution is straitened to some parts in the north, north-west and northeast. The NE trade wind ensures a permanently humid climate in the north. Major urban and industrial development is centred on Tenerife, and as a touristy hotspot the Island is exposed to heavy air traffic. Furthermore, the short distance to the African coastline and, therefore, to the Sahara, contribute a regular influence of African Dust emissions. In summary, Laurel Forest is exposed to different climatic conditions, variations in lithology and soils, and aerosols caused by local anthropogenic emissions, Saharan dust, and sea spray. The present study aims to understand geogenic and anthropogenic element transports of K, P, N, and organic components between soils and Laurel Forest. In addition, the element contribution from the aerosols such as the Sahara dust has to be quantified to understand the rock - soil - vegetation coupling system. The Sahara dust as one of the important aerosols has been studied by various researchers (Bustos et al., 1998; Rodrıguez, 1999; Torres et al., 2001; Viana et al., 2002). Viana et al.,(2002) quantified the impacts of African dust outbreaks for Tenerife and Gran Canaria, after the interpretation of the PM10 (thoracis particulate matter) from nineteen air quality monitoring stations. Three types of African dust contributions were identified and characterized (winter, summer and autumn-winter dust outbreaks). Collected samples with and without African dust influence proved that: (a) for the intensive winter African dust outbreaks (daily PM10 levels up to 191 mg/m3) at least 76% of the bulk PM10 levels may be attributable to dust load, whereas the anthropogenic input accounts for only 3-14% and (b) SiO2, Al2O3, Ca, K, Fe, Ti, V, Mn and Ba concentrations are excellent tracers of African origin (Viana et al., 2002).

Atmospheric imaging results from the Mars Exploration Rovers

NASA Astrophysics Data System (ADS)

Lemmon, M.; Athena Science Team

The Athena science payload of the Spirit and Opportunity Mars Exploration Rovers contains instruments capable of measuring radiometric properties of the Martian atmosphere in the visible and the thermal infrared. Remote sensing instruments include Pancam, a color panoramic camera covering 0.4-1.0 microns, and Mini-TES, a thermal infrared spectrometer covering 5-29 microns. Results from atmospheric imaging by Pancam will be covered here. Visible and near-infrared aerosol opacity is monitored by direct solar imaging. Early results show dust opacity near 1 when both rovers landed. Both Spirit and Opportunity have seen dust opacity fall with time, somewhat faster at Spirit's Gusev crater landing site. Diurnal variations are also being monitored at both sites. There is no direct probe of the dust's vertical distribution, but images of the Sun near the horizon and of the twilight will provide constraints on the dust distribution. Dust optical properties and a cross-section weighted aerosol size will be estimated from Pancam images of the sky at varying geometries and times of day. A series of sky imaging sequences has been run with varying illumination geometry. The observations are similar to those reported for Mars Pathfinder.

Transport of Alaskan Dust into the Gulf of Alaska and Comparison with Similar High-Latitude Dust Environments

NASA Technical Reports Server (NTRS)

Crusium, John; Levy, Rob; Wang, Jun; Campbell, Rob; Schroth, Andrew W.

2012-01-01

Transport of Alaskan dust into the Gulf of Alaska and comparison with similar high-latitude dust environments. An airborne flux of the micronutrient iron, derived from dust originating from coastal regions may be an important contributor of iron to the Gulf of Alaska's (GoA) oligotrophic waters. Dust blowing off glacier termini and dry riverbeds is a recurring phenomenon in Alaska, usually occurring in the autumn. Since previous studies assumed that dust originating in the deserts of Asia was the largest source of . airborne iron to the GoA, the budget of aeolian deposition of iron needs to be reassessed. Since late 20 I 0, our group has been monitoring dust activity using satellites over the Copper River Delta (CRD) where the most vigorous dust plumes have been observed. Since 2011, sample aerosol concentration and their composition are being collected at Middleton Island (100km off shore of CRD). This presentation will show a summary of the ongoing dust observations and compare with other similar environments (Patagonia, Iceland) by showing case studies. Common features will be highlighted

Dust storms and their impact on ocean and human health: dust in Earth's atmosphere

USGS Publications Warehouse

Griffin, Dale W.; Kellog, Christina A.

2004-01-01

Satellite imagery has greatly influenced our understanding of dust activity on a global scale. A number of different satellites such as NASA's Earth-Probe Total Ozone Mapping Spectrometer (TOMS) and Se-viewing Field-of-view Sensor (SeaWiFS) acquire daily global-scale data used to produce imagery for monitoring dust storm formation and movement. This global-scale imagery has documented the frequent transmission of dust storm-derived soils through Earth's atmosphere and the magnitude of many of these events. While various research projects have been undertaken to understand this normal planetary process, little has been done to address its impact on ocean and human health. This review will address the ability of dust storms to influence marine microbial population densities and transport of soil-associated toxins and pathogenic microorganisms to marine environments. The implications of dust on ocean and human health in this emerging scientific field will be discussed.

Temperature and Humidity Calibration of a Low-Cost Wireless Dust Sensor for Real-Time Monitoring.

PubMed

Hojaiji, Hannaneh; Kalantarian, Haik; Bui, Alex A T; King, Christine E; Sarrafzadeh, Majid

2017-03-01

This paper introduces the design, calibration, and validation of a low-cost portable sensor for the real-time measurement of dust particles within the environment. The proposed design consists of low hardware cost and calibration based on temperature and humidity sensing to achieve accurate processing of airborne dust density. Using commercial particulate matter sensors, a highly accurate air quality monitoring sensor was designed and calibrated using real world variations in humidity and temperature for indoor and outdoor applications. Furthermore, to provide a low-cost secure solution for real-time data transfer and monitoring, an onboard Bluetooth module with AES data encryption protocol was implemented. The wireless sensor was tested against a Dylos DC1100 Pro Air Quality Monitor, as well as an Alphasense OPC-N2 optical air quality monitoring sensor for accuracy. The sensor was also tested for reliability by comparing the sensor to an exact copy of itself under indoor and outdoor conditions. It was found that accurate measurements under real-world humid and temperature varying and dynamically changing conditions were achievable using the proposed sensor when compared to the commercially available sensors. In addition to accurate and reliable sensing, this sensor was designed to be wearable and perform real-time data collection and transmission, making it easy to collect and analyze data for air quality monitoring and real-time feedback in remote health monitoring applications. Thus, the proposed device achieves high quality measurements at lower-cost solutions than commercially available wireless sensors for air quality.

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...

Study on the alternative mitigation of cement dust spread by capturing the dust with fogging method

NASA Astrophysics Data System (ADS)

Purwanta, Jaka; Marnoto, Tjukup; Setyono, Prabang; Handono Ramelan, Ari

2017-12-01

The existence of a cement plant impact the lives of people around the factory site. For example the air quality, which is polluted by dust. Cement plant has made various efforts to mitigate the generated dust, but there are still alot of dust fly inground either from the cement factory chimneys or transportation. The purpose of this study was to conduct a review of alternative mitigation of the spread of dust around the cement plant. This study uses research methods such as collecting secondary data which includes data of rain density, the average rains duration, wind speed and direction as well as data of dust intensity quality around PT. Semen Gresik (Persero) Tbk.Tuban plant. A soft Wind rose file is used To determine the wind direction propensity models. The impact on the spread of dust into the environment is determined using secondary data monitoring air quality. Results of the study is that the mitigation of dust around the cement plant is influenced by natural factors, such as the tendency of wind direction, rain fall and rainy days, and the rate of dust emission from the chimney. The alternative means proposed is an environmental friendly fogging dust catcher.

Monitoring Comet 67P/C-G Micrometer Dust Flux: GIADA onboard Rosetta.

NASA Astrophysics Data System (ADS)

Della Corte, Vincenzo; Rotundi, Alessandra; Ivanovski, Stavro; Accolla, Mario; Ferrari, Marco; Sordini, Roberto; Lucarelli, Francesca; Zakharov, Vladimir; Fulle, Marco; Mazzotta Epifani, Elena; López-Moreno, José J.; Rodríguez, Julio; Colangeli, Luigi; Palumbo, Pasquale; Bussoletti, Ezio; Crifo, Jean-Francois; Esposito, Francesca; Green, Simon F.; Grün, Eberhard; Lamy, Philippe L.

2015-04-01

(21)ESA-ESAC, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spagna The MicroBalance System (MBS) is one of the three measurement subsystems of GIADA, the Grain Impact Analyzer and Dust Accumulator on board the Rosetta/ESA spacecraft (S/C). It consists of five Quartz Crystal Microbalances (QCMs) in roughly orthogonal directions providing the cumulative dust flux of grains smaller than 10 microns. The MBS is continuously monitoring comet 67P/CG since the beginning of May 2014. During the first 4 months of measurements, before the insertion of the S/C in the bound orbit phase, there were no evidences of dust accumulation on the QCMs. Starting from the beginning of October, three out of five QCMs measured an increase of the deposited dust. The measured fluxes show, as expected, a strong anisotropy. In particular, the dust flux appears to be much higher from the Sun direction with respect to the comet direction. Acknowledgment: GIADA was built by a consortum led by the Univ. Napoli "Parthenope" & INAF- Oss. Astr. Capodimonte, in collaboration with the Inst. de Astrofisica de Andalucia, Selex-ES, FI and SENER. GIADA is presently managed & operated by Ist. di Astrofisica e Planetologia Spaziali-INAF, IT. GIADA was funded and managed by the Agenzia Spaziale Italiana, IT, with the support of the Spanish Ministry of Education and Science MEC, ES. GIADA was developed from a PI proposal from the University of Kent; sci. & tech. contribution were provided by CISAS, IT, Lab. d'Astr. Spat., FR, and Institutions from UK, IT, FR, DE and USA. We thank the RSGS/ESAC, RMOC/ESOC & Rosetta Project/ESTEC for their out-standing work. Science support provided was by NASA through the US Rosetta Project managed by the Jet Propulsion Laboratory/ California Institute of Technology. GIADA calibrated data will be available through ESA's PSA web site (www.rssd.esa.int/index.php? project=PSA&page=in dex). We would like to thank Angioletta Coradini for her contribution as a GIADA Co-I.

Using albedo to reform wind erosion modelling, mapping and monitoring

USDA-ARS?s Scientific Manuscript database

Dust emission models are used to assess the impacts of dust on radiative forcing in the atmosphere, cloud formation, nutrient fertilisation and human health. We describe a need in aeolian research to adequately represent the spatial variability and particularly the area average of the key aerodynami...

Using shadow to reformulate wind erosion modelling, mapping and monitoring

USDA-ARS?s Scientific Manuscript database

Wind erosion and dust emission models are required to assess the impacts of dust in the Earth system. We describe a need in aeolian research to adequately represent the spatial variability and particularly the area average of the key aerodynamic properties which influence these models and our unders...

30 CFR 27.40 - Test to determine resistance to dust.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Test to determine resistance to dust. 27.40 Section 27.40 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS METHANE-MONITORING SYSTEMS Test Requirements § 27.40 Test to...

Dust formation in Nova Oph 2017 (TCP J17394608-2457555)

NASA Astrophysics Data System (ADS)

Joshi, Vishal; Banerjee, D. P. K.; Srivastava, Mudit

2017-06-01

Ongoing NIR observations of Nova Oph 2017 indicate the possible onset of dust formation in Nova Oph 2017. Monitoring in the JHKs bands shows a steady rise in the J-K color from around 1.4 on 5 June 2017 to 2.0 on 13 June 2017.

Quantitative detection of settled coal dust over green canopy

NASA Astrophysics Data System (ADS)

Brook, Anna; Sahar, Nir

2017-04-01

The main task of environmental and geoscience applications are efficient and accurate quantitative classification of earth surfaces and spatial phenomena. In the past decade, there has been a significant interest in employing spectral unmixing in order to retrieve accurate quantitative information latent in in situ data. Recently, the ground-truth and laboratory measured spectral signatures promoted by advanced algorithms are proposed as a new path toward solving the unmixing problem in semi-supervised fashion. This study presents a practical implementation of field spectroscopy as a quantitative tool to detect settled coal dust over green canopy in free/open environment. Coal dust is a fine powdered form of coal, which is created by the crushing, grinding, and pulverizing of coal. Since the inelastic nature of coal, coal dust can be created during transportation, or by mechanically handling coal. Coal dust, categorized at silt-clay particle size, of particular concern due to heavy metals (lead, mercury, nickel, tin, cadmium, mercury, antimony, arsenic, isotopes of thorium and strontium) which are toxic also at low concentrations. This hazard exposes risk on both environment and public health. It has been identified by medical scientist around the world as causing a range of diseases and health problems, mainly heart and respiratory diseases like asthma and lung cancer. It is due to the fact that the fine invisible coal dust particles (less than 2.5 microns) long lodge in the lungs and are not naturally expelled, so long-term exposure increases the risk of health problems. Numerus studies reported that data to conduct study of geographic distribution of the very fine coal dust (smaller than PM 2.5) and related health impacts from coal exports, is not being collected. Sediment dust load in an indoor environment can be spectrally assessed using reflectance spectroscopy (Chudnovsky and Ben-Dor, 2009). Small amounts of particulate pollution that may carry a signature of a forthcoming environmental hazard are of key interest when considering the effects of pollution. According to the most basic distribution dynamics, dust consists of suspended particulate matter in a fine state of subdivision that are raised and carried by wind. In this context, it is increasingly important to first, understand the distribution dynamics of pollutants, and subsequently develop dedicated tools and measures to control and monitor pollutants in the free environment. The earliest effect of settled polluted dust particles is not always reflected through poor conditions of vegetation or soils, or any visible damages. In most of the cases, it has a quite long accumulation process that graduates from a polluted condition to long-term environmental and health related hazard. Although conducted experiments with pollutant analog powders under controlled conditions have tended to con- firm the findings from field studies (Brook, 2014; Brook and Ben-Dor 2016; Brook, 2016), a major criticism of all these experiments is their short duration. The resulting conclusion is that it is difficult, if not impossible, to determine the implications of long-term exposure to realistic concentrations of pollutants from such short-term studies. In general, the task of unmixing is to decompose the reflectance spectrum into a set of endmembers or principal combined spectra and their corresponding abundances (Bioucas-Dias et al., 2012). This study suggests that the sensitivity of sparse unmixing techniques provides an ideal approach to extract and identify coal dust settled over/upon green vegetation canopy using in situ spectral data collected by portable spectrometer. The optimal NMF algorithms, such as ALS and LPG, are assumed to be the simplest methods that achieve the minimum error. The suggested practical approach includes the following stages: 1. In situ spectral measurements, 2. Near-real-time spectral data analysis, 3. Estimated concentration of coal dust reported as mg/sq m. The stage 2 is completed by calculating: 1. Unmixing between the green canopy and the settle dust extraction only coal dust fraction, 2. Converting spectral feature of coal dust to concentration via PLSR spectral model. The spectral model was trained and validated PLSR model developed at laboratory using spectra across MIR (FTIR reflectance spectra) and NIR regions and XRD analysis. The obtained RMSE was satisfying for both spectral regions. Thus, it was concluded that field spectroscopy can be used for this purpose, and it can provide fully quantitative measures of settle coal dust. Nowadays this approach (both spectrometer and algorithm) has been accepted as a practical operational tool for environmental monitoring near power station Orot Rabin in Hadera and will be used by the Sharon-Carmel Districts Municipal Association for Environmental Protection, Israel as a regulatory tool. In summary, this work shows that coal dust can be assessed using in situ spectroscopy, making it a potentially powerful tool for environmental studies. References Chudnovsky, A., & Ben-Dor, E. (2009). Reflectance spectroscopy as a tool for settled dust monitoring in office environment. International Journal of Environment and Waste Management, 4(1), 32-49. Brook, A. (2014). Quantitative Detection of Settled dust over Green Canopy using Sparse Unmixing of Airborne Hyperspectral Data. IEEE-Whispers 6th Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing, 2014, Switzerland, 4-8. Brook, A. and Ben-Dor, E. (2016). Quantitative detection of settled dust over Green Canopy using sparse unmixing of airborne hyperspectral data. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 9(2), pp.884-897. Brook, A. (2016). Quantitative Detection and Long-Term Monitoring of Settle Dust Using Semisupervised Learning for Spectral Data. Water, Air, & Soil Pollution, 227(3), pp.1-9. Bioucas-Dias, J.M., Plaza, A., Dobigeon, N., Parente, M., Du, Q., Gader, P. and Chanussot, J. (2012). Hyperspectral unmixing overview: Geometrical, statistical, and sparse regression-based approaches. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 5(2), pp.354-379. Keshava, N., Mustard, J. (2002). Spectral unmixing. IEEE Signal Process. Mag., 19(1), 44-57. Bioucas-Dias et al. (2012). Hyperspectral unmixing overview: Geometrical, statistical, and sparse regression-based approaches, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 5(2), 354 -379.

Air Quality Monitoring: Risk-Based Choices

NASA Technical Reports Server (NTRS)

James, John T.

2009-01-01

Air monitoring is secondary to rigid control of risks to air quality. Air quality monitoring requires us to target the credible residual risks. Constraints on monitoring devices are severe. Must transition from archival to real-time, on-board monitoring. Must provide data to crew in a way that they can interpret findings. Dust management and monitoring may be a major concern for exploration class missions.

Dusty Donuts: Modeling the Reverberation Response of the Circumnuclear Dusty Torus Emission in AGN

NASA Astrophysics Data System (ADS)

Almeyda, Triana R.

The obscuring circumnuclear torus of dusty molecular gas is one of the major components of AGN (active galactic nuclei), yet its size, composition, and structure are not well understood. These properties can be studied by analyzing the temporal variations of the infrared (IR) dust emission from the torus in response to variations in the AGN continuum luminosity; a technique known as reverberation mapping. In a recent international campaign 12 AGN were monitored using the Spitzer Space Telescope and several ground-based telescopes, providing a unique set of well-sampled mid-IR and optical light curves which are required in order to determine the approximate sizes of the tori in these AGN. To help extract structural information contained in the data a computer model, TORMAC, has been developed that simulates the reverberation response of the clumpy torus emission. Given an input optical light curve, the code computes the emission of a 3D ensemble of dust clouds as a function of time at selected IR wavelengths, taking into account light travel delays. A large library of torus reverberation response simulations has been constructed, to investigate the effects of various geometrical and structural properties such as inclination, cloud distribution, disk half-opening angle, and radial depth. The effects of dust cloud orientation, cloud optical depth, anisotropy of the illuminating AGN radiation field, dust cloud shadowing, and cloud occultation are also explored in detail. TORMAC was also used to generate synthetic IR light curves for the Seyfert 1 galaxy, NGC 6418, using the observed optical light curve as the input, to investigate how the torus and dust cloud properties incorporated in the code affect the results obtained from reverberation mapping. This dissertation presents the most comprehensive investigation to date showing that radiative transfer effects within the torus and anisotropic illumination of the torus can strongly influence the torus IR response at different wavelengths, and should be accounted for when interpreting reverberation mapping data. TORMAC provides a powerful modeling tool that can generate simulated IR light curves for direct comparison to observations. As many types of astronomical sources are both variable and embedded in, or surrounded, by dust, TORMAC also has applications for dust reverberation studies well beyond the AGN observed in the Spitzer monitoring campaign.

Dust Storm Covers Opportunity

NASA Image and Video Library

2018-06-10

This global map of Mars shows a growing dust storm as of June 6, 2018. The map was produced by the Mars Color Imager (MARCI) camera on NASA's Mars Reconnaissance Orbiter spacecraft. The blue dot shows the approximate location of Opportunity. The storm was first detected on June 1. The MARCI camera has been used to monitor the storm ever since. Full dust storms like this one are not surprising, but are infrequent. They can crop up suddenly but last weeks, even months. During southern summer, sunlight warms dust particles, lifting them higher into the atmosphere and creating more wind. That wind kicks up yet more dust, creating a feedback loop that NASA scientists still seek to understand. https://photojournal.jpl.nasa.gov/catalog/PIA22329

Martian Dust Devils: 2 Mars Years of MGS MOC Observations

NASA Astrophysics Data System (ADS)

Cantor, B. A.; Edgett, K. S.

2002-12-01

Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide and narrow angle images have captured more than 1000 active dust devils over 2 Mars years. In the most recent Mars year, we repeatedly imaged (and are continuing to image) several areas to monitor dust devil occurrence. Some Mars dust devils are as small as a few to 10s of meters across, others are 100s of meters across and over 6 km high. Each Martian hemisphere has a "dust devil season" that generally follows the subsolar latitude. An exception is NW Amazonis, which has frequent, large dust devils throughout northern spring and summer (probably every afternoon; observations are acquired 2-3 times a week). The Amazonis and other MOC observations show no evidence that dust devils cause, lead to, or have a systematic relationship with dust storms. However, dust devils sometimes do occur near small, localized storms; and one specific relation occurred during the onset of the global dust events of 2001: slightly elevated levels of atmospheric dust (an optically thin cloud) triggered a very short period of dust devil activity in NW Amazonis in early northern autumn. The redistribution of dust by the 2001 global events may have also affected subsequent spring and summer dust devil activity in Hellas, where considerably fewer dust devils occurred in 2001-2002 than 1999-2000. In SW Syria, frequent, large dust devils occurred after the 2001 global events and persisted through southern summer. While dust devils have no specific relation to dust storms, they might play a role in the seasonal "wave of darkening" at middle and high latitudes by removing or disrupting thin veneers of dust. Dust devils have been observed to create thin, filamentary streaks. Some streaks are darker than their surroundings, while others are lighter. Some dust devils do not create streaks. At mid-latitudes, surfaces darken in spring as 100s of crisscrossing streaks form on widely-varied terrain. Some rare streaks exhibit cycloidal patterns similar to those created on Earth by tornadoes with multiple sub-vortices. The streaks occur at nearly all latitudes and elevations, from north polar dunes to the south polar layered terrain, from the summit of Olympus Mons to the floor of Hellas. During "dust devil season" at a given latitude, tremendous changes in streak patterns occur in periods as short as 1 month. These observations, along with repeated imaging in NW Amazonis and SW Syria, provide some idea of the frequency of dust devils. Uncertain is whether dust devils are responsible for all thin, filamentary streaks: while active vortices have been seen creating the plethora of streaks at southern mid-latitudes, none have been observed on the northern plains, despite observation of similar streak patterns. Perhaps northern plains dust devils occur at a different time of day relative to the MGS 1400 LT orbit, or perhaps dust devils did not form them. We monitored removal of dust from surfaces after the 2001 global dust events in several locations. Of particular interest was western Syrtis Major, which had brightened considerably after the 2001 storms. We observed this area for several months while very little change occurred. Finally, in January 2002, the surface was swept clean of most of its 2001 veneer of dust in a period of about 1 week. Dust devils played no role in this process; instead, regional surface winds were responsible.

Correction: Alvarado, M., et al. Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites. Sensors 2015, 15, 19667-19687.

PubMed

Alvarado, Miguel; Gonzalez, Felipe; Fletcher, Andrew; Doshi, Ashray

2016-07-05

The author wishes to change Figure 1 and Figure 3 from his paper published in Sensors [1], doi:10.3390/s150819667, website: http://www.mdpi.com/1424-8220/15/8/19667 for Figures 1 and 2 presented in this 'Correction'.[...].

Integrating Windblown Dust Forecasts with Public Safety and Health Systems

NASA Astrophysics Data System (ADS)

Sprigg, W. A.

2014-12-01

Experiments in real-time prediction of desert dust emissions and downstream plume concentrations (~ 3.5 km near-surface spatial resolution) succeed to the point of challenging public safety and public health services to beta test a dust storm warning and advisory system in lowering risks of highway and airline accidents and illnesses such as asthma and valley fever. Key beta test components are: high-resolution models of dust emission, entrainment and diffusion, integrated with synoptic weather observations and forecasts; satellite-based detection and monitoring of soil properties on the ground and elevated above; high space and time resolution for health surveillance and transportation advisories.

The Dust Storm Index (DSI): A method for monitoring broadscale wind erosion using meteorological records

NASA Astrophysics Data System (ADS)

O'Loingsigh, T.; McTainsh, G. H.; Tews, E. K.; Strong, C. L.; Leys, J. F.; Shinkfield, P.; Tapper, N. J.

2014-03-01

Wind erosion of soils is a natural process that has shaped the semi-arid and arid landscapes for millennia. This paper describes the Dust Storm Index (DSI); a methodology for monitoring wind erosion using Australian Bureau of Meteorology (ABM) meteorological observational data since the mid-1960s (long-term), at continental scale. While the 46 year length of the DSI record is its greatest strength from a wind erosion monitoring perspective, there are a number of technical challenges to its use because when the World Meteorological Organisation (WMO) recording protocols were established the use of the data for wind erosion monitoring was never intended. Data recording and storage protocols are examined, including the effects of changes to the definition of how observers should interpret and record dust events. A method is described for selecting the 180 long-term ABM stations used in this study and the limitations of variable observation frequencies between stations are in part resolved. The rationale behind the DSI equation is explained and the examples of temporal and spatial data visualisation products presented include; a long term national wind erosion record (1965-2011), continental DSI maps, and maps of the erosion event types that are factored into the DSI equation. The DSI is tested against dust concentration data and found to provide an accurate representation of wind erosion activity. As the ABM observational records used here were collected according to WMO protocols, the DSI methodology could be used in all countries with WMO-compatible meteorological observation and recording systems.

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...

VLTI monitoring of the dust formation event of the Nova V1280 Scorpii

NASA Astrophysics Data System (ADS)

Chesneau, O.; Banerjee, D. P. K.; Millour, F.; Nardetto, N.; Sacuto, S.; Spang, A.; Wittkowski, M.; Ashok, N. M.; Das, R. K.; Hummel, C.; Kraus, S.; Lagadec, E.; Morel, S.; Petr-Gotzens, M.; Rantakyro, F.; Schöller, M.

2008-08-01

Context: We present the first high spatial-resolution monitoring of the dust-forming nova V1280 Sco, performed with the Very Large Telescope Interferometer (VLTI). Aims: These observations promise to improve the distance determination of such events and constrain the mechanisms leading to very efficient dust formation under the harsh physical conditions encountered in novae ejecta. Methods: Spectra and visibilities were regularly acquired between the onset of dust formation, 23 days after discovery (or 11 days after maximum), and day 145, using the beam-combiner instruments AMBER (near-IR) and MIDI (mid-IR). These interferometric observations were complemented by near-infrared data from the 1.2 m Mt. Abu Infrared Observatory, India. The observations are initially interpreted in terms of simple uniform models; however more complex models, probably involving a second shell, are required to explain data acquired following t=110 d after outburst. This behavior is in accordance with the light curve of V1280 Sco, which exhibits a secondary peak at about t=106 d, followed by a new, steep decline, suggesting a new dust-forming event. Spherical dust shell models generated with the DUSTY code are used to investigate the parameters of the main dust shell. Results: Using uniform disk models, these observations allow us to determine an apparent linear expansion rate for the dust shell of 0.35 ± 0.03 mas day-1 and the approximate ejection time of the matter in which dust formed of t_ejec = 10.5 ± 7 d, i.e. close to the maximum brightness. This information, combined with the expansion velocity of 500 ± 100 km s-1, implies a distance estimate of 1.6 ± 0.4 kpc. The sparse uv coverage does not enable deviations from spherical symmetry to be clearly discerned. The dust envelope parameters were determined. The dust mass generated was typically 2-8 × 10-9 M_⊙ day-1, with a probable peak in production at about 20 days after the detection of dust and another peak shortly after t=110 d, when the amount of dust in the shell was estimated as 2.2 × 10-7 M_⊙. Considering that the dust-forming event lasted at least 200-250 d, the mass of the ejected material is likely to have exceeded 10-4 M_⊙. The conditions for the formation of multiple shells of dust are also discussed. Based on observations made with the Very Large Telescope Interferometer at Paranal Observatory under programs 278.D-5053, 279.D-5014 and 079.D-0415.

East Asian dust storm in May 2017: observations, modelling and its influence on Asia-Pacific region

USDA-ARS?s Scientific Manuscript database

A severe dust storm event originated from the Gobi Desert in Central and East Asia during 2-7 May, 2017. Based on moderate resolution imaging spectroradiometer (MODIS) satellite products, hourly environmental monitoring measurements from 367 Chinese cities and more than 2000 East Asian meteorologica...

Multiband infrared inversion for low-concentration methane monitoring in a confined dust-polluted atmosphere.

PubMed

Wang, Wenzheng; Wang, Yanming; Song, Wujun; Li, Xueqin

2017-03-20

A multiband infrared diagnostic (MBID) method for methane emission monitoring in limited underground environments was presented considering the strong optical background of gas/solid attenuation. Based on spatial distribution of aerosols and complex refractive index of dust particles, forward calculations were carried out with/without methane to obtain the spectral transmittance through the participating atmosphere in a mine roadway. Considering the concurrent attenuation and absorption behavior of dust and gases, four infrared wavebands were selected to retrieve the methane concentration combined with a stochastic particle swarm optimization (SPSO) algorithm. Inversion results prove that the presented MBID method is robust and effective in identifying methane at concentrations of 0.1% or even lower with inversed relative error within 10%. Further analyses illustrate that the four selected wavebands are indispensable, and the MBID method is still valid with transmission signal disturbance in a conventional dust-polluted atmosphere under mechanized mining condition. However, the effective detection distance should be limited within 50 m to ensure inversed relative error less than 5% at 1% methane concentration.

Mid-infrared Flux Variability in an Awakening AGN

NASA Astrophysics Data System (ADS)

Yeh, Sherry

We propose FORCAST spectroscopic observations between 8 um to 40 um near the nucleus of NGC 660. NGC 660 underwent an AGN outburst 6 years ago, which is an ideal case for studying AGN astrophysics in a rather quiecent system. However, this rare event has not yet been monitored. Our immidiate goal is to verify the MIR spectroscipic variabilitiy in NGC 660, and to study the AGN effects on dust destruction and ISM. We will compare the FORCAST spectra with the Spitzer IRS spectra (taken before the AGN outburst), including dust continuum, PAH emission, and high- and low-ionization emission lines. FORCAST's slit width is a close match to the IRS slit width, allowing a direct comparison of the spectra between FORCAST and IRS. Our single-slit Subaru COMICS spectrum taken after the outburst shows significantly weakened PAH emission and dust continuum, suggesting dust destruction. However, it is difficult to draw robust intepretations due to systematic uncertainties in the Subaru data. If dust destruction is confirmed in the post-outburst FORCAST observaitons, we will evaluate the energy budget using the MIR line ratio diagnostics, with archival X-ray and radio data. We will then propose cadence observations of MGC 660's nucleus to monitor the MIR flux variability, and employ the reverberation mapping technique to study NGC 660's AGN.

Restoration and Reexamination of Apollo Lunar Dust Detector Data from Original Telemetry Files

NASA Technical Reports Server (NTRS)

McBride, M. J.; Williams, David R.; Hills, H. Kent

2012-01-01

We are recovering the original telemetry (Figure I) from the Apollo Dust, Thermal, Radiation Environment Monitor (DTREM) experiment, more commonly known as the Dust Detector, and producing full time resolution (54 second) data sets for release through the Planetary Data System (PDS). The primary objective of the experiment was to evaluate the effect of dust deposition, temperature, and radiation damage on solar cells on the lunar surface. The monitor was a small box consisting of three solar cells and thermistors mounted on the ALSEP (Apollo Lunar Surface Experiments Package) central station. The Dust Detector was carried on Apollo's 11, 12, 14 and 15. The Apollo 11 DTREM was powered by solar cells and only operated for a few months as planned. The Apollo 12, 14, and 15 detectors operated for 5 to 7 years, returning data every 54 seconds, consisting of voltage outputs from the three solar cells and temperatures measured by the three thermistors. The telemetry was received at ground stations and held on the Apollo Housekeeping (known as "Word 33") tapes. made available to the National Space Science Data Center (NSSDC) by Yosio Nakamura (University of Texas Institute for Geophysics). We have converted selected parts of the telemetry into uncalibrated and calibrated output voltages and temperatures.

Pinwheels in the sky, with dust: 3D modelling of the Wolf-Rayet 98a environment

NASA Astrophysics Data System (ADS)

Hendrix, Tom; Keppens, Rony; van Marle, Allard Jan; Camps, Peter; Baes, Maarten; Meliani, Zakaria

2016-08-01

The Wolf-Rayet 98a (WR 98a) system is a prime target for interferometric surveys, since its identification as a `rotating pinwheel nebulae', where infrared images display a spiral dust lane revolving with a 1.4 yr periodicity. WR 98a hosts a WC9+OB star, and the presence of dust is puzzling given the extreme luminosities of Wolf-Rayet stars. We present 3D hydrodynamic models for WR 98a, where dust creation and redistribution are self-consistently incorporated. Our grid-adaptive simulations resolve details in the wind collision region at scales below one percent of the orbital separation (˜4 au), while simulating up to 1300 au. We cover several orbital periods under conditions where the gas component alone behaves adiabatic, or is subject to effective radiative cooling. In the adiabatic case, mixing between stellar winds is effective in a well-defined spiral pattern, where optimal conditions for dust creation are met. When radiative cooling is incorporated, the interaction gets dominated by thermal instabilities along the wind collision region, and dust concentrates in clumps and filaments in a volume-filling fashion, so WR 98a must obey close to adiabatic evolutions to demonstrate the rotating pinwheel structure. We mimic Keck, ALMA or future E-ELT observations and confront photometric long-term monitoring. We predict an asymmetry in the dust distribution between leading and trailing edge of the spiral, show that ALMA and E-ELT would be able to detect fine-structure in the spiral indicative of Kelvin-Helmholtz development, and confirm the variation in photometry due to the orientation. Historic Keck images are reproduced, but their resolution is insufficient to detect the details we predict.

Characterization of dust activity from Martian Year (MY) 27 to MY 32 observed by the Planetary Fourier Spectrometer aboard the Mars Express spacecraft

NASA Astrophysics Data System (ADS)

Wolkenberg, Paulina; Giuranna, Marco; Aoki, Shohei; Scaccabarozzi, Diego; Saggin, Bortolino; Formisano, Vittorio

2016-04-01

More than 2,500,000 spectra have been collected by the Planetary Fourier Spectrometer aboard Mars Express spacecraft after 12 years of activity. The data span more than six Martian years, from MY26, Ls = 331°, to MY 33, Ls = 78°. This huge dataset has been used to build a new database of atmospheric parameters, including atmospheric and surface temperatures, and dust and water ice opacity. Dust aerosols suspended in the atmosphere affect its thermal structure and are a major driver of the circulation. They are always present in the Martian atmosphere, but the amount varies greatly depending on location and season. We analyze dust opacities at 1075 cm-1 retrieved from the PFS long-wavelength channel spectra to characterize the dust activity on Mars for the relevant period. The dust storm season (Ls= 185° - 310°) is monitored for each Martian year. All dust observations show a seasonal pattern, which is ruled by the occurrence of regional and/or global dust storms. Regional dust storms are observed every year, while a planet encircling dust storm occurred in MY 28, when the highest values of dust opacity are also observed (~ 2.45). We characterize the spatial and temporal evolution of these regional and global dust events and investigate the effect of dust on surface and atmospheric temperatures.

30 CFR 57.5002 - Exposure monitoring.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Exposure monitoring. 57.5002 Section 57.5002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... monitoring. Dust, gas, mist, and fume surveys shall be conducted as frequently as necessary to determine the...

Global Monitoring of Martian Surface Albedo Changes from Orbital Observations

NASA Astrophysics Data System (ADS)

Geissler, P.; Enga, M.; Mukherjee, P.

2013-12-01

Martian surface changes were first observed from orbit during the Mariner 9 and Viking Orbiter missions. They were found to be caused by eolian processes, produced by deposition of dust during regional and global dust storms and subsequent darkening of the surface through erosion and transportation of dust and sand. The albedo changes accumulated in the 20 years between Viking and Mars Global Surveyor were sufficient to alter the global circulation of winds and the climate of Mars according to model calculations (Fenton et al., Nature 2007), but little was known about the timing or frequency of the changes. Since 1999, we have had the benefit of continuous monitoring by a series of orbiting spacecraft that continues today with Mars Reconnaissance Orbiter, Mars Odyssey, and Mars Express. Daily synoptic observations enable us to determine whether the surface albedo changes are gradual or episodic in nature and to record the seasons that the changes take place. High resolution images of surface morphology and atmospheric phenomena help identify the physical mechanisms responsible for the changes. From these data, we hope to learn the combinations of atmospheric conditions and sediment properties that produce surface changes on Mars and possibly predict when they will take place in the future. Martian surface changes are particularly conspicuous in low albedo terrain, where even a thin layer of bright dust brightens the surface drastically. Equatorial dark areas are repeatedly coated and recoated by dust, which is later shed from the surface by a variety of mechanisms. An example is Syrtis Major, suddenly buried in bright dust by the global dust storm of 2001. Persistent easterly winds blew much of the dust cover away over the course of the next Martian year, but episodic changes continue today, particularly during southern summer when regional dust storms are rife. Another such region is Solis Planum, south of the Valles Marineris, where changes take place relentlessly in all seasons as bright dust and dark sand battle to dominate the landscape. Elsewhere, gradual processes steadily shift albedo boundaries between bright and dark terrain. Dark terrain near the Spirit rover landing site is gradually spreading to the north, driven by seasonal southerly winds. A bright fringe of newly deposited dust appears ahead of the moving boundary, populated by wind streaks and dust avalanches. Dark terrain at higher latitudes gradually creeps towards the equator by the dust cleaning action of dust devils, for example at Nilosytis (43°N, 85°E). Much less obvious is the deposition and erosion of dust on already bright, dust-covered terrain. Changes in the distribution of fresh dust take place frequently in the region surrounding the Tharsis Montes. Dust in this high altitude zone is constantly on the move as faint dark streaks mark the removal of recently deposited dust that is only slightly brighter than the dust already settled on the surface. Dramatic deposition of dust onto dusty terrain took place at much lower elevations in northwestern Amazonis between 2002 and 2005. Since then, the dust has been energetically eroded by towering dust devils that cluster here each summer.

Lidar Measurements for Desert Dust Characterization: An Overview

NASA Technical Reports Server (NTRS)

Mona, L.; Liu, Z.; Mueller, D.; Omar, A.; Papayannis, A.; Pappalardo, G.; Sugimoto, N.; Vaughan, M.

2012-01-01

We provide an overview of light detection and ranging (lidar) capability for describing and characterizing desert dust. This paper summarizes lidar techniques, observations, and fallouts of desert dust lidar measurements. The main objective is to provide the scientific community, including non-practitioners of lidar observations with a reference paper on dust lidar measurements. In particular, it will fill the current gap of communication between research-oriented lidar community and potential desert dust data users, such as air quality monitoring agencies and aviation advisory centers. The current capability of the different lidar techniques for the characterization of aerosol in general and desert dust in particular is presented. Technical aspects and required assumptions of these techniques are discussed, providing readers with the pros and cons of each technique. Information about desert dust collected up to date using lidar techniques is reviewed. Lidar techniques for aerosol characterization have a maturity level appropriate for addressing air quality and transportation issues, as demonstrated by some first results reported in this paper

Interannual variability of planet-encircling dust storms on Mars

NASA Technical Reports Server (NTRS)

Zurek, Richard W.; Martin, Leonard J.

1993-01-01

A recent review of earth-based telescopic observations of Mars together with Viking orbiter and lander data are employed to estimate the frequency of occurrence of planet-encircling dust storms over the past century and to test whether the period spanned by the Mariner 9 and Viking missions to Mars is representative of the decades prior to 1950. Both spacecraft and earth-based observations suggest that planet-encircling dust storms on Mars occur during a 'dust storm season' in southern spring and summer. Viking data show that planet-encircling dust storms could have occurred in the past on Mars without being detected from earth during years in which Mars was far from earth during the dust storm season. Planet-encircling storms were absent during the dust storm seasons monitored during several favorable oppositions prior to 1956 and after 1986. The change of a planet-encircling dust storm occurring in any arbitrary Mars year is estimated to be approximately one in three, if this occurrence is random from year to year and yet restricted seasonally to southern spring and summer.

Adapting MODIS Dust Mask Algorithm to Suomi NPP VIIRS for Air Quality Applications

NASA Astrophysics Data System (ADS)

Ciren, P.; Liu, H.; Kondragunta, S.; Laszlo, I.

2012-12-01

Despite pollution reduction control strategies enforced by the Environmental Protection Agency (EPA), large regions of the United States are often under exceptional events such as biomass burning and dust outbreaks that lead to non-attainment of particulate matter standards. This has warranted the National Weather Service (NWS) to provide smoke and dust forecast guidance to the general public. The monitoring and forecasting of dust outbreaks relies on satellite data. Currently, Aqua/MODIS (MODerate resolution Imaging Spectrometer) and Terra/MODIS provide measurements needed to derive dust mask and Aerosol Optical Thickness (AOT) products. The newly launched Suomi NPP VIIRS (Visible/Infrared Imaging Radiometer Suite) instrument has a Suspended Matter (SM) product that indicates the presence of dust, smoke, volcanic ash, sea salt, and unknown aerosol types in a given pixel. The algorithm to identify dust is different over land and ocean but for both, the information comes from AOT retrieval algorithm. Over land, the selection of dust aerosol model in the AOT retrieval algorithm indicates the presence of dust and over ocean a fine mode fraction smaller than 20% indicates dust. Preliminary comparisons of VIIRS SM to CALIPSO Vertical Feature Mask (VFM) aerosol type product indicate that the Probability of Detection (POD) is at ~10% and the product is not mature for operational use. As an alternate approach, NESDIS dust mask algorithm developed for NWS dust forecast verification that uses MODIS deep blue, visible, and mid-IR channels using spectral differencing techniques and spatial variability tests was applied to VIIRS radiances. This algorithm relies on the spectral contrast of dust absorption at 412 and 440 nm and an increase in reflectivity at 2.13 μm when dust is present in the atmosphere compared to a clear sky. To avoid detecting bright desert surface as airborne dust, the algorithm uses the reflectances at 1.24 μm and 2.25 μm to flag bright pixels. The algorithm flags pixels that fall into the glint region so sun glint is not picked up as dust. The algorithm also has a spatial variability test that uses reflectances at 0.86 μm to screen for clouds over water. Analysis of one granule for a known dust event on May 2, 2012 shows that the agreement between VIIRS and MODIS is 82% and VIIRS and CALIPSO is 71%. The probability of detection for VIIRS when compared to MODIS and CALIPSO is 53% and 45% respectively whereas the false alarm ratio for VIIRS when compared to MODIS and CALIPSO is 20% and 37% respectively. The algorithm details, results from the test cases, and the use of the dust flag product in NWS applications will be presented.

Emerging ecological datasets with application for modeling North American dust emissions

USDA-ARS?s Scientific Manuscript database

In 2011 the US Bureau of Land Management (BLM) established the Assessment, Inventory and Monitoring (AIM) program to monitor the condition of BLM land and to provide data to support evidence-based management of multi-use public lands. The monitoring program shares core data collection methods with t...

Limb clouds and dust on Mars from images obtained by the Visual Monitoring Camera (VMC) onboard Mars Express

NASA Astrophysics Data System (ADS)

Sánchez-Lavega, A.; Chen-Chen, H.; Ordoñez-Etxeberria, I.; Hueso, R.; del Río-Gaztelurrutia, T.; Garro, A.; Cardesín-Moinelo, A.; Titov, D.; Wood, S.

2018-01-01

The Visual Monitoring Camera (VMC) onboard the Mars Express (MEx) spacecraft is a simple camera aimed to monitor the release of the Beagle-2 lander on Mars Express and later used for public outreach. Here, we employ VMC as a scientific instrument to study and characterize high altitude aerosols events (dust and condensates) observed at the Martian limb. More than 21,000 images taken between 2007 and 2016 have been examined to detect and characterize elevated layers of dust in the limb, dust storms and clouds. We report a total of 18 events for which we give their main properties (areographic location, maximum altitude, limb projected size, Martian solar longitude and local time of occurrence). The top altitudes of these phenomena ranged from 40 to 85 km and their horizontal extent at the limb ranged from 120 to 2000 km. They mostly occurred at Equatorial and Tropical latitudes (between ∼30°N and 30°S) at morning and afternoon local times in the southern fall and northern winter seasons. None of them are related to the orographic clouds that typically form around volcanoes. Three of these events have been studied in detail using simultaneous images taken by the MARCI instrument onboard Mars Reconnaissance Orbiter (MRO) and studying the properties of the atmosphere using the predictions from the Mars Climate Database (MCD) General Circulation Model. This has allowed us to determine the three-dimensional structure and nature of these events, with one of them being a regional dust storm and the two others water ice clouds. Analyses based on MCD and/or MARCI images for the other cases studied indicate that the rest of the events correspond most probably to water ice clouds.

Preliminary Results from the STARDUST Encounter with Wild 2 Comet obtained by the Dust Flux Monitor Instrument

NASA Astrophysics Data System (ADS)

Economou, T. E.; Tuzzolino, A. J.; Green, S. F.

On January 2nd, 2004, the Stardust spacecraft successfully encountered the Wild 2 comet. The Dust Flux Monitor Instrument (DFMI) provided quantitative measurements of dust particle fluxes and particle mass distribution throughout the entire flythrough. The DFMI consists of two different dust detector systems --- a polyvinylidene fluoride (PVDF) dust sensor unit (SU), which measures particles in the 10-11 to 10-4 mass, and a dual acoustic sensor system (DASS), which utilizes two piezoelectric accelerometers mounted on the first two layers of the spacecraft Whipple dust shield to measure the flux ofparticles with mass larger than 10-4 g. The DFMI on the stardust mission was designed, built and tested at the University of Chicago. The Open University provided the calibration and will perform the analysis of the data from the acoustic sensors. The DFMI instrument was turned on 15 minutes before the estimated closest approach. It started to detect the first dust particles just a few minutes before the closest approach with both types of the sensors in the instrument. As the S/C was departing the comet several more dust particle streams were encountered some 2-12 minutes after the closest approach. The time distribution of dust particles detected by DFMI is not uniform and they seem to come in closely spaced swarms of particles separated by many seconds with no events. The source of these particles is believed to be several of the jet streams that were observed in many of the images obtained by the navigation camera on the STARDUST spacecraft. Data flux rates and dust particle mass distribution are currently being evaluated and will be presented at the meeting. The instrument detected thousands of small particles and a few of them were large enough to even penetrate the first layer of the Whipple bumper shield. From the DFMI data it has been estimated that more than several thousands particles larger than 20 μ in diameter have been collected in the aerogel collector that will returned back to Earth in January 2006.

Impact and monitoring of dust storms in Taklimakan desert

NASA Astrophysics Data System (ADS)

Feng, G. G.; Li, X.; Zheng, Z.

2012-12-01

The Taklimakan is China's largest, driest, and warmest desert in total area of 338000km^2 with perimeter of 436 km, it is also known as one of the world's largest shifting-sand deserts. Fully 85 percent of the total area consists of mobile, crescent-shaped sand dunes and are virtually devoid of vegetation. The abundant sand provides material for frequent intense dust storms. The Taklimakan desert fills the expansive Tarim Basin between the Kunlun Mountains and the Tibet Plateau to the south and the Tian Shan Mountains to the north. The Tarim River flows across the basin from west-to-east. In these places, the oases created by fresh surface water support agriculture. Studies outside Xinjiang indicated that 80% dust source of storms was from farmland. Dust storms in the Tarim Basin occur for 20 to 59 days, mainly in spring every year. However, little effort was taken to investigate soil wind erosion and dust emission around the desert. Quantitative understanding of individual dust events in the arid Taklimakan desert, for example, the dust emission rates and the long-range transport, are still incomplete. Therefore, the dust events were observed through routine satellite sensors, lidar instruments, airborne samplers, and surface-based aerosol monitors. Soil wind erosion and suspended particulates emission of four major dust storms from the desert and the typical oasis farmlands at the north rim of the desert were measured using creep sampler, BSNE and TSP at eight heights in 2012. In addition, Aqua satellite AOD data, the NAAPS Global Aeosol model, the CALIPSO satellite products, EPA's AirNow AQI of PM2.5 and HYSPLIT Back Trajectory model were applied to analyze dust transport across the Pacific. Four significant dust storms were observed at the north rim of Taklimakan desert in the spring, 2012. During those events, predominant wind direction ranged from 296 to 334°, wind speed over 7 m/s at 2 m lasted for 471-1074 min, gust wind speed ranged from 11-18m/s. It was determined that the horizontal dust flux was 0.6 to 4.3 kg/m. Dust clouds are formed when the friction from high surface wind speeds (>6 m/s) lifts loose dust particles into the atmospheric boundary layer or above. Analysis shows that a dust storm in the Taklimakan desert on April 23th produced a huge atmospheric dust cloud, it was transported across the Pacific Ocean to reach the West Coast of North America 12 days later, corresponding to 6 m/s average transport speed. The observations in the Pacific Coast indicated that aerosol concentrations were elevated which resulted in Air Quality Index (AQI) to the yellow moderate category.

Estimating Children’s Soil/Dust Ingestion Rates through Retrospective Analyses of Blood Lead Biomonitoring from the Bunker Hill Superfund Site in Idaho

PubMed Central

von Lindern, Ian; Spalinger, Susan; Stifelman, Marc L.; Stanek, Lindsay Wichers; Bartrem, Casey

2016-01-01

Background: Soil/dust ingestion rates are important variables in assessing children’s health risks in contaminated environments. Current estimates are based largely on soil tracer methodology, which is limited by analytical uncertainty, small sample size, and short study duration. Objectives: The objective was to estimate site-specific soil/dust ingestion rates through reevaluation of the lead absorption dose–response relationship using new bioavailability data from the Bunker Hill Mining and Metallurgical Complex Superfund Site (BHSS) in Idaho, USA. Methods: The U.S. Environmental Protection Agency (EPA) in vitro bioavailability methodology was applied to archived BHSS soil and dust samples. Using age-specific biokinetic slope factors, we related bioavailable lead from these sources to children’s blood lead levels (BLLs) monitored during cleanup from 1988 through 2002. Quantitative regression analyses and exposure assessment guidance were used to develop candidate soil/dust source partition scenarios estimating lead intake, allowing estimation of age-specific soil/dust ingestion rates. These ingestion rate and bioavailability estimates were simultaneously applied to the U.S. EPA Integrated Exposure Uptake Biokinetic Model for Lead in Children to determine those combinations best approximating observed BLLs. Results: Absolute soil and house dust bioavailability averaged 33% (SD ± 4%) and 28% (SD ± 6%), respectively. Estimated BHSS age-specific soil/dust ingestion rates are 86–94 mg/day for 6-month- to 2-year-old children and 51–67 mg/day for 2- to 9-year-old children. Conclusions: Soil/dust ingestion rate estimates for 1- to 9-year-old children at the BHSS are lower than those commonly used in human health risk assessment. A substantial component of children’s exposure comes from sources beyond the immediate home environment. Citation: von Lindern I, Spalinger S, Stifelman ML, Stanek LW, Bartrem C. 2016. Estimating children’s soil/dust ingestion rates through retrospective analyses of blood lead biomonitoring from the Bunker Hill Superfund Site in Idaho. Environ Health Perspect 124:1462–1470; http://dx.doi.org/10.1289/ehp.1510144 PMID:26745545

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

76 FR 30878 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-27

... Eastern Daylight Saving Time on June 20, 2011. ADDRESSES: Comments must be identified with ``RIN 1219-AB64... commenters additional time to review and comment on the proposed rule. DATES: The comment period for the... providing additional time for interested parties to submit comments. MSHA is extending the comment period...

Endotoxins in cotton: washing effects and size distribution

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

Olenchock, S.A.; Mull, J.C.; Jones, W.G.

1983-01-01

Endotoxin contamination was measured in washed and unwashed cottons from three distinct growing areas, California, Mississippi, and Texas. The data show differences in endotoxin contamination based upon the geographic source of the cotton. It is also shown that washing bulk cotton before the carding process results in lower endotoxin in the cotton dust. Washing conditions can affect the endotoxin levels, and all size fractions of the airborne dust contain quantifiable endotoxin contamination. Endotoxin analyses provide a simple and reliable method for monitoring the cleanliness of cotton or airborne cotton dusts.

First-Time Analysis of Completely Restored DTREM Instrument Data from Apollo 14 and 15

NASA Technical Reports Server (NTRS)

McBride, Marie J.; Williams, David R.; Hills, H. Kent; Turner, Niescja

2013-01-01

The Dust, Thermal and Radiation Engineering Measurement (DTREM) packages (figure 1) mounted on the central stations of the Apollo 11, 12, 14, and 15 ALSEPs (Apollo Lunar Surface Experiments Packages) measured the outputs of exposed solar cells and thermistors over time. The goal of the experiment, also commonly known as the dust detector, was to study the long-term effects of dust, radiation, and temperature at the lunar surface on solar cells. The monitors returned data for up to almost 8 years from the lunar surface.

Slope Streaks on a Dusty Planet

NASA Image and Video Library

2015-05-06

Mars is a dusty place and in some locations thick blankets of its characteristically red dust can slowly settle out of the atmosphere and accumulate on slopes. This dust is also a lot brighter than the dust-free terrain on Mars; so, if you scrape off the dust, you'll see a darker surface underneath. This particular image shows one of these dusty areas. The dark streaks on the slopes are locations where the dust has slumped downhill revealing a less dusty surface underneath. In some cases, these slope streaks might be triggered by Marsquakes or nearby meteorite impacts. Scientists think they form quickly: more like an avalanche than dust slowly creeping downhill. Look more closely and you'll notice that some streaks are darker than others. Dust is settling out of the atmosphere all the time and these dark streaks get slowly buried by fresh dust so that they fade back into their brighter redder surroundings. It's not certain how long this fading takes to happen, but it's probably close to a few decades. Dust is an important player in the weather and climate on Mars. Images like this are used to monitor slow changes in these streaks over time to better understand how much dust is settling on the surface. http://photojournal.jpl.nasa.gov/catalog/PIA19456

The effect of air dust pollution on semen quality and sperm parameters among infertile men in west of Iran.

PubMed

Najafpour, Ali; Aghaz, Faranak; Roshankhah, Shiva; Bakhtiari, Mitra

2018-06-26

Pollutants during haze and Asian dust storms are transported out of the Asian continent, affecting the regional climate and the hydrological and biogeochemical cycles. Nonetheless, no specific studies evaluated the dust particles influence on semen quality in a specific geographical area. In this article, we investigated the effect of dust particles on semen quality and sperm parameters among infertile men. A descriptive-analytic study was conducted among 850 infertile men between 2011 and 2015 years. Semen quality was assessed according to the WHO 2010 guidelines, including sperm concentration, progressive motility, and morphology. Four-year average dust particle concentrations were estimated at each participant's address using the Air Pollution Monitoring Station affiliated with the Department of Environment of Kermanshah city were gathered. Dust particle levels were highest in the summer months, in Kermanshah province. Our results show that, dust pollution was found to be significantly negatively correlated with sperm morphology and sperm concentration before and after lab-processing, but sperm progressive motility is low sensitive to dust particles. Our findings showed that exposures to dust particle may influence sperm quantity in infertile men, consistent with the knowledge that sperm morphology and concentration are the most sensitive parameters of dust pollution.

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).

Empirical Model for Evaluating PM10 Concentration Caused by River Dust Episodes

PubMed Central

Lin, Chao-Yuan; Chiang, Mon-Ling; Lin, Cheng-Yu

2016-01-01

Around the estuary of the Zhuo-Shui River in Taiwan, the waters recede during the winter, causing an increase in bare land area and exposing a large amount of fine earth and sand particles that were deposited on the riverbed. Observations at the site revealed that when northeastern monsoons blow over bare land without vegetation or water cover, the fine particles are readily lifted by the wind, forming river dust, which greatly endangers the health of nearby residents. Therefore, determining which factors affect river dust and constructing a model to predict river dust concentration are extremely important in the research and development of a prototype warning system for areas at risk of river dust emissions. In this study, the region around the estuary of the Zhuo-Shui River (from the Zi-Qiang Bridge to the Xi-Bin Bridge) was selected as the research area. Data from a nearby air quality monitoring station were used to screen for days with river dust episodes. The relationships between PM10 concentration and meteorological factors or bare land area were analyzed at different temporal scales to explore the factors that affect river dust emissions. Study results showed that no single factor alone had adequate power to explain daily average or daily maximum PM10 concentration. Stepwise regression analysis of multiple factors showed that the model could not effectively predict daily average PM10 concentration, but daily maximum PM10 concentration could be predicted by a combination of wind velocity, temperature, and bare land area; the coefficient of determination for this model was 0.67. It was inferred that river dust episodes are caused by the combined effect of multiple factors. In addition, research data also showed a time lag effect between meteorological factors and hourly PM10 concentration. This characteristic was applied to the construction of a prediction model, and can be used in an early warning system for local residents. PMID:27271642

Empirical Model for Evaluating PM10 Concentration Caused by River Dust Episodes.

PubMed

Lin, Chao-Yuan; Chiang, Mon-Ling; Lin, Cheng-Yu

2016-06-02

Around the estuary of the Zhuo-Shui River in Taiwan, the waters recede during the winter, causing an increase in bare land area and exposing a large amount of fine earth and sand particles that were deposited on the riverbed. Observations at the site revealed that when northeastern monsoons blow over bare land without vegetation or water cover, the fine particles are readily lifted by the wind, forming river dust, which greatly endangers the health of nearby residents. Therefore, determining which factors affect river dust and constructing a model to predict river dust concentration are extremely important in the research and development of a prototype warning system for areas at risk of river dust emissions. In this study, the region around the estuary of the Zhuo-Shui River (from the Zi-Qiang Bridge to the Xi-Bin Bridge) was selected as the research area. Data from a nearby air quality monitoring station were used to screen for days with river dust episodes. The relationships between PM10 concentration and meteorological factors or bare land area were analyzed at different temporal scales to explore the factors that affect river dust emissions. Study results showed that no single factor alone had adequate power to explain daily average or daily maximum PM10 concentration. Stepwise regression analysis of multiple factors showed that the model could not effectively predict daily average PM10 concentration, but daily maximum PM10 concentration could be predicted by a combination of wind velocity, temperature, and bare land area; the coefficient of determination for this model was 0.67. It was inferred that river dust episodes are caused by the combined effect of multiple factors. In addition, research data also showed a time lag effect between meteorological factors and hourly PM10 concentration. This characteristic was applied to the construction of a prediction model, and can be used in an early warning system for local residents.

Coma dust environment observed by GIADA during the Perihelion of 67P/Churyumov-Gerasimenko.

NASA Astrophysics Data System (ADS)

Rotundi, A.; Della Corte, V.; Fulle, M.; Ferrari, M.; Ivanovski, S. L.; Sordini, R.; Mazzotta Epifani, E.; Palumbo, P.; Colangeli, L.; Lopez-Moreno, J. J.; Rodriguez, J.; Zakharov, V.; Bussoletti, E.; Crifo, J. F.; Esposito, F.; Green, S.; Gruen, E.; Lamy, P. L.; McDonnell, T.; Mennella, V.; Molina, A.; Moreno, F.; Ortiz, J. L.; Palomba, E.; Perrin, J. M.; Rodrigo, R.; Weissman, P. R.; Zarnecki, J.; Cosi, M.; Giovane, F.; Gustafson, B.; Herranz, M.; Jeronimo, J. M.; Leese, M.; Lopez-Jimenez, A.; Morales, R.

2015-12-01

GIADA (Grain Impact Analyzer and Dust Accumulator) is an in-situ instrument mounted onboard Rosetta monitoring the dust environment of comet 67P/Churyumov-Gerasimenko. GIADA is composed of 3 sub-systems: 1) the Grain Detection System, based on particle detection through light scattering; 2) the Impact Sensor, giving momentum measurement; 3) the Micro-Balances System, constituted of 5 quartz crystal microbalances, giving cumulative deposited dust. The combination of the measurements performed by these 3 subsystems provides: the number, the mass, the momentum and the speed distribution of dust particles emitted from the comet nucleus. We will present the coma dust environment as observed by GIADA during the perihelion phase of the Rosetta space mission. Despite the large distance from the nucleus, more than 200 km, GIADA was able to detect temporal and spatial variation of dust density distribution. Specific high dust spatial density sectors of the coma have been identified and their evolution during the perihelion phase was studied. Acknowledgements. GIADA was built by a consortium led by the Univ. Napoli "Parthenope" & INAF- Oss. Astr. Capodimonte, IT, in collaboration with the Inst. de Astrofisica de Andalucia, ES, Selex-ES s.p.a. and SENER. GIADA is presently managed & operated by Ist. di Astrofisica e Planetologia Spaziali-INAF, IT. GIADA was funded and managed by the Agenzia Spaziale Italiana, IT, with a support of the Spanish Ministry of Education and Science MEC, ES. GIADA was developped from a PI proposal supported by the University of Kent; sci. & tech. contribution given by CISAS, IT, Lab. d'Astr. Spat., FR, and Institutions from UK, IT, FR, DE and USA. We thank the RSGS/ESAC, RMOC/ESOC & Rosetta Project/ESTEC for their outstanding work. Science support provided by NASA through the US Rosetta Project managed by JPL/California Institute of Technology. GIADA calibrated data will be available through the ESA's PSA web site.

High Proportions of Sub-micron Particulate Matter in Icelandic Dust Storms in 2015

NASA Astrophysics Data System (ADS)

Dagsson Waldhauserova, Pavla; Arnalds, Olafur; Olafsson, Haraldur; Magnusdottir, Agnes

2017-04-01

Iceland is extremely active dust region and desert areas of over 44,000 km2 acknowledge Iceland as the largest Arctic and European desert. Frequent dust events, up to 135 dust days annually, transport dust particles far distances towards the Arctic and Europe. Satellite MODIS pictures have revealed dust plumes exceeding 1,000 km. The annual dust deposition was calculated as 40.1 million tons yr-1. Two dust storms were measured in transverse horizontal profile about 90 km far from different dust sources in southwestern Iceland in the summer of 2015. Aerosol monitor DustTrak DRX 8533EP was used to measure PM mass concentrations corresponding to PM1, PM2.5, PM4, PM10 and the total PM15 at several places within the dust plume. Images from camera network operated by the Icelandic Road and Coastal Administration were used to estimate the visibility and spatial extent of measured dust events. A numerical simulation of surface winds was carried out with the numerical model HIRLAM with horizontal resolution of 5 km and used to calculate the total dust flux from the sources. The in situ measurements inside the dust plumes showed that aeolian dust can be very fine. The study highlights that suspended volcanic dust in Iceland causes air pollution with extremely high PM1 concentrations comparable to the polluted urban stations in Europe or Asia rather than reported dust event observations from around the world. The PM1/PM2.5 ratios are generally low during dust storms outside of Iceland, much lower than > 0.9 and PM1/PM10 ratios of 0.34-0.63 found in our study. It shows that Icelandic volcanic dust consists of higher proportion of submicron particles compared to crustal dust. The submicron particles are predicted to travel long distances. Moreover, such submicron particles pose considerable health risk because of high potential for entering the lungs. Icelandic volcanic glass has often fine pipe-vesicular structures known from asbestos and high content of heavy metals. Previous in situ measurements at the dust source in 2013 revealed extremely high number concentrations of submicron particles, specifically in the size range 0.3-0.337 μm. The PM2.5/PM10 ratios of mass concentrations seem to be lower at the dust sources that in some distance from the sources as measured in 2015. Common dust storms in Iceland are of several hundred thousand tons of magnitude from relatively well defined main dust sources. Numerical simulations were used calculate the total dust flux from the sources as 180,000 - 280,000 tons in this study. The mean PM1 (PM10) concentrations inside of the dust plumes varied from 97 to 241 µg m-3 (PM10 = 158 to 583 µg m-3). The extent of moderate dust events was calculated as 2.450 km2 to 4.220 km2 of the land area suggesting the regional scale of the events. Dust plumes reported here passed the most densely inhabited areas of Iceland, health risk warnings for the general public were, however, not issued. The data provided stresses the need for such warning system and is an important step towards its development.

Sorption of Organophosphorus Flame-Retardants on Settled ...

EPA Pesticide Factsheets

Dust is an important sink for indoor air pollutants, such as organophosphorus flame-retardants (OPFRs) that are used as additives in industrial and consumer products including electrical and electronic products, furniture, plastics, textile, and building/construction materials. This research investigated the sorption of OPFRs, tris(2-chloroethyl) phosphate (TCEP), tris(1-chlor-2-propyl) phosphate (TCPP), and tris(1,3-dichloro-2-propyl) phosphate (TDCPP) on settled Arizona Test Dust (ATD) using a dual small chamber system. During the test, seven free film release paper dust trays covered with ATD were placed in the sink test chamber. Constant gas phase OPFRs from the source chamber were dosed into the test chamber. The dust evenly spread on each dust tray was removed from the test chamber at different exposure times to determine the amount of OPFRs absorbed by the dust. The ATD has been characterized for a nominal particle size and surface area. The mass of dust on each of seven dust trays was weighed before the dust was placed inside the sink chamber. OPFRs concentrations at the inlet and faceplate of the test chamber were monitored by collecting polyurethane foam (PUF) samples. The OPFR exposed dust and PUF samples were extracted by 1:1 ethyl acetate/methylene chloride and analyzed on GC/MS. The data were used to calculate the OPFR sorption concentration on the dust through dust/air partition. Settled dust can adsorb OPFR from air. The sorption concentration wa

Estimating historical respirable crystalline silica exposures for Chinese pottery workers and iron/copper, tin, and tungsten miners.

PubMed

Zhuang, Z; Hearl, F J; Odencrantz, J; Chen, W; Chen, B T; Chen, J Q; McCawley, M A; Gao, P; Soderholm, S C

2001-11-01

Collaborative studies of Chinese workers, using over four decades of dust monitoring data, are being conducted by the National Institute for Occupational Safety and Health (NIOSH) and Tongji Medical University in China. The goal of these projects is to establish exposure-response relationships for the development of diseases such as silicosis or lung cancer in cohorts of pottery and mine workers. It is necessary to convert Chinese dust measurements to respirable silica measurements in order to make results from the Chinese data comparable to other results in the literature. This article describes the development of conversion factors and estimates of historical respirable crystalline silica exposure for Chinese workers. Ambient total dust concentrations (n>17000) and crystalline silica concentrations (n=347) in bulk dust were first gathered from historical industrial hygiene records. Analysis of the silica content in historical bulk samples revealed no trend from 1950 up to the present. During 1988-1989, side-by-side airborne dust samples (n=143 pairs) were collected using nylon cyclones and traditional Chinese samplers in 20 metal mines and nine pottery factories in China. These data were used to establish conversion factors between respirable crystalline silica concentrations and Chinese total dust concentrations. Based on the analysis of the available evidence, conversion factors derived from the 1988-1989 sampling campaign are assumed to apply to other time periods in this paper. The conversion factors were estimated to be 0.0143 for iron/copper, 0.0355 for pottery factories, 0.0429 for tin mines, and 0.0861 for tungsten mines. Conversion factors for individual facilities within each industry were also calculated. Analysis of variance revealed that mean conversion factors are significantly different among facilities within the iron/copper industry and within the pottery industry. The relative merits of using facility-specific conversion factors, industry-wide conversion factors, or a weighted average of the two are discussed. The exposure matrix of the historical Chinese total dust concentrations was multiplied by these conversion factors to obtain an exposure matrix of historical respirable crystalline silica concentrations.

Field and laboratory comparison of PM10 instruments in high winds

NASA Astrophysics Data System (ADS)

Sharratt, Brenton; Pi, Huawei

2018-06-01

Instruments capable of measuring PM10 (particulate matter ≤10 μm in aerodynamic diameter) concentrations may vary in performance as a result of different technologies utilized in measuring PM10. Therefore, the performance of five instruments capable of measuring PM10 concentrations above eroding soil surfaces was tested during high wind events at field sites in the Columbia Plateau and inside a wind tunnel. Comparisons among the Big Spring Number Eight (BSNE) sampler, DustTrak monitor, E-sampler, High-Volume sampler, and Tapered Element Oscillating Microbalance (TEOM) monitor were made at field sites during nine wind erosion events and inside a wind tunnel at two wind speeds (7 and 12 m s-1) and two ambient PM10 concentrations (2 and 50 mg m-3). PM10 concentrations were similar for the High-Volume sampler and TEOM monitor as well as for the BSNE samplers and DustTrak monitors but higher for the High-Volume sampler and TEOM monitor than the E-sampler during field erosion events. Based upon wind tunnel experiments, the TEOM monitor measured the highest PM10 concentration while the DustTrak monitor typically measured the lowest PM10 concentration as compared with other instruments. In addition, PM10 concentration appeared to lower for all instruments at a wind speed of 12 as compared with 7 m s-1 inside the wind tunnel. Differences in the performance of instruments in measuring PM10 concentration poses risks in comparing PM10 concentration among different instrument types or using multiple instrument types to jointly measure concentrations in the field or laboratory or even the same instrument type subject to different wind speeds.

Impact of Aerosol Dust on xMAP Multiplex Detection of Different Class Pathogens

PubMed Central

Kleymenov, Denis A.; Gushchin, Vladimir A.; Gintsburg, Alexander L.; Tkachuk, Artem P.

2017-01-01

Environmental or city-scale bioaerosol surveillance can provide additional value for biodefense and public health. Efficient bioaerosol monitoring should rely on multiplex systems capable of detecting a wide range of biologically hazardous components potentially present in air (bacteria, viruses, toxins and allergens). xMAP technology from LuminexTM allows multiplex bead-based detection of antigens or nucleic acids, but its use for simultaneous detection of different classes of pathogens (bacteria, virus, toxin) is questionable. Another problem is the detection of pathogens in complex matrices, e.g., in the presence of dust. In the this research, we developed the model xMAP multiplex test-system aiRDeTeX 1.0, which enables detection of influenza A virus, Adenovirus type 6 Salmonella typhimurium, and cholera toxin B subunit representing RNA virus, DNA virus, gram-negative bacteria and toxin respectively as model organisms of biologically hazardous components potentially present in or spreadable through the air. We have extensively studied the effect of matrix solution (PBS, distilled water), environmental dust and ultrasound treatment for monoplex and multiplex detection efficiency of individual targets. All targets were efficiently detectable in PBS and in the presence of dust. Ultrasound does not improve the detection except for bacterial LPS. PMID:29238328

Wet Dust Deposition Across Texas, USA

NASA Astrophysics Data System (ADS)

Collins, J. D., Jr.; Ponette-González, A.; Gill, T. E.; Glass, G. A.; Weathers, K. C.

2016-12-01

Atmospheric dust deposition is of critical importance in terrestrial biogeochemical cycles, supplying essential limiting nutrients, such as calcium and phosphorus as well as pollutants, such as lead, to ecosystems. Dust particles are delivered to terrestrial ecosystems directly as dry deposition or in precipitation (wet deposition) as a result of rainout (particles incorporated into cloud droplets) and washout (particles that collide with raindrops as they fall). Compared to dry deposition, wet dust deposition (dissolved + particulate) is a poorly understood yet potentially significant pathway for dust input, especially in humid regions. We quantified wet dust deposition to two National Atmospheric Deposition Monitoring (NADP) sites across Texas-one in west (Guadalupe Mountains) and one in east (near Houston) Texas-with contrasting climate/dust regimes and land cover. We focused on 2012 during one of the most severe droughts in Texas since 1895. Dust event days (DEDs) were identified using meteorological data for stations within 150 km of the NADP sites where wet deposition was sampled weekly. DEDs were defined using the following criteria: visibility <10 km, <30% relative humidity, and wind speed >50 km, supplemented with other Saharan dust incursion and dust observations. A total of 34 DEDs (20 sample weeks) were identified for the west and 5 DEDs (4 sample weeks) for the east Texas sites. Bulk elemental composition of washout particles is analyzed using Particle Induced X-ray Emission (PIXE) spectroscopy and X-ray Fluorescence (XRF) spectroscopy. Using these data, we will examine differences in the chemical composition of rainwater and aerosol particles filtered from rain samples for dust versus non-dust event days at each study site. Deposition fluxes for dust and non-dust event weeks are also compared. Quantifying the magnitude of wet dust deposition is necessary to improve evaluation of dust impacts on biogeochemical cycles.

Dust from mineral extraction: regulation of emissions in England

NASA Astrophysics Data System (ADS)

Marker, Brian

2013-04-01

The United Kingdom, which includes England, has fairly high levels of rainfall but sporadic droughts occur especially in the east. Mineral working gives rise to dust. Concerns about dust soiling are major source of public objections to new minerals extraction operations. Dust emissions from mineral workings are a significant cause of public concern in the United Kingdom and are recognised as sources of health concerns and nuisance. Emissions are controlled through a number of complementary sets of regulations that are generally well observed by the industry and well enforced by the relevant public authorities. comprehensive system of regulation, based on European and national law, to deal with all aspects of these operations including pollution control, planning, occupational health and safety and statutory nuisances. Most minerals applications are subject to EIA which forms that basis for planning and environmental conditions and monitoring of operations. There are limit values on PM10 and PM2.5 in air, and for potentially harmful elements (PHEs) in soils and water, derived from European regulations but, as yet, no limit values for PHEs (other than radioactive materials) in air. Stakeholder engagement is encouraged so that members of the public can express concerns during minerals operations and operators can quickly deal with these. While some effects inevitably remain, the levels of dust emissions are kept low through good site design and management, proper use of machinery which is equipped to minimise emissions, and good training of the workforce. Operational sites are required to have dust monitoring equipment located outside the site boundary so that any emerging problems can be detected and addressed quickly.

An Evaluation of Sharp Cut Cyclones for Sampling Diesel Particulate Matter Aerosol in the Presence of Respirable Dust

PubMed Central

Cauda, Emanuele; Sheehan, Maura; Gussman, Robert; Kenny, Lee; Volkwein, Jon

2015-01-01

Two prototype cyclones were the subjects of a comparative research campaign with a diesel particulate matter sampler (DPMS) that consists of a respirable cyclone combined with a downstream impactor. The DPMS is currently used in mining environments to separate dust from the diesel particulate matter and to avoid interferences in the analysis of integrated samples and direct-reading monitoring in occupational environments. The sampling characteristics of all three devices were compared using ammonium fluorescein, diesel, and coal dust aerosols. With solid spherical test aerosols at low particle loadings, the aerodynamic size-selection characteristics of all three devices were found to be similar, with 50% penetration efficiencies (d50) close to the design value of 0.8 µm, as required by the US Mine Safety and Health Administration for monitoring occupational exposure to diesel particulate matter in US mining operations. The prototype cyclones were shown to have ‘sharp cut’ size-selection characteristics that equaled or exceeded the sharpness of the DPMS. The penetration of diesel aerosols was optimal for all three samplers, while the results of the tests with coal dust induced the exclusion of one of the prototypes from subsequent testing. The sampling characteristics of the remaining prototype sharp cut cyclone (SCC) and the DPMS were tested with different loading of coal dust. While the characteristics of the SCC remained constant, the deposited respirable coal dust particles altered the size-selection performance of the currently used sampler. This study demonstrates that the SCC performed better overall than the DPMS. PMID:25060240

Influence of Desert Dust Intrusions on Ground-based and Satellite Derived Ultraviolet Irradiance in Southeastern Spain

NASA Technical Reports Server (NTRS)

Krotkov, Nickolay A.; Anton, Manuel; Valenzuela, Antonio; Roman, Roberto; Lyamani, Hassan; Arola, Antti; Olmo, Francisco J.; Alados-Arboledas

2012-01-01

The desert dust aerosols strongly affect propagation of solar radiation through the atmosphere, reducing surface irradiance available for photochemistry and photosynthesis. This paper evaluates effects of desert dust on surface UV erythemal irradiance (UVER), as measured by a ground-based broadband UV radiometer and retrieved from the satellite Ozone Monitoring Instrument (OMI) at Granada (southern Spain) from January 2006 to December 2010. The dust effects are characterized by the transmittance ra tio of the measured UVER to the corresponding modeled clear sky value. The transmittance has an exponential dependency on aerosol optical depth (AOD), with minimum values of approximately 0.6 (attenuation of approximately 40%). The OMI UVER algorithm does not account for UV aerosol absorption, which results in overestimation of the ground-based UVER especially during dust episodes with a mean relative difference up to 40%. The application of aerosol absorption post-correction method reduces OMI bias up to approximately 13%. The results highlight great effect of desert dust on the surface UV irradiance in regions like southern Spain, where dust intrusions from Sahara region are very frequent.

Transparent self-cleaning dust shield

DOEpatents

Mazumder, Malay K.; Sims, Robert A.; Wilson, James D.

2005-06-28

A transparent electromagnetic shield to protect solar panels and the like from dust deposition. The shield is a panel of clear non-conducting (dielectric) material with embedded parallel electrodes. The panel is coated with a semiconducting film. Desirably the electrodes are transparent. The electrodes are connected to a single-phase AC signal or to a multi-phase AC signal that produces a travelling electromagnetic wave. The electromagnetic field produced by the electrodes lifts dust particles away from the shield and repels charged particles. Deposited dust particles are removed when the electrodes are activated, regardless of the resistivity of the dust. Electrostatic charges on the panel are discharged by the semiconducting film. When used in conjunction with photovoltaic cells, the power for the device may be obtained from the cells themselves. For other surfaces, such as windshields, optical windows and the like, the power must be derived from an external source. One embodiment of the invention employs monitoring and detection devices to determine when the level of obscuration of the screen by dust has reached a threshold level requiring activation of the dust removal feature.

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.

Artificial stone dust-induced functional and inflammatory abnormalities in exposed workers monitored quantitatively by biometrics.

PubMed

Ophir, Noa; Shai, Amir Bar; Alkalay, Yifat; Israeli, Shani; Korenstein, Rafi; Kramer, Mordechai R; Fireman, Elizabeth

2016-01-01

The manufacture of kitchen and bath countertops in Israel is based mainly on artificial stone that contains 93% silica as natural quartz, and ∼3500 workers are involved in cutting and processing it. Artificial stone produces high concentrations of silica dust. Exposure to crystalline silica may cause silicosis, an irreversible lung disease. Our aim was to screen exposed workers by quantitative biometric monitoring of functional and inflammatory parameters. 68 exposed artificial stone workers were compared to 48 nonexposed individuals (controls). Exposed workers filled in questionnaires, and all participants underwent pulmonary function tests and induced sputum analyses. Silica was quantitated by a Niton XL3 X-ray fluorescence spectrometer. Pulmonary function test results of exposed workers were significantly lower and induced sputa showed significantly higher neutrophilic inflammation compared to controls; both processes were slowed down by the use of protective measures in the workplace. Particle size distribution in induced sputum samples of exposed workers was similar to that of artificial stone dust, which contained aluminium, zirconium and titanium in addition to silica. In conclusion, the quantitation of biometric parameters is useful for monitoring workers exposed to artificial stone in order to avoid deterioration over time.

Weather and Climate on the Reliability of Enviromagnetic Studies of Tree Leaves in Air Pollution Monitoring

NASA Astrophysics Data System (ADS)

Rey, D.; Rodríguez-Germade, I.; Mohamed Falcon, K. J.; Rubio, B.; Garcia, A.

2014-12-01

Monthly monitoring of the magnetic properties of Platanus hispanica tree leaves to assess atmospheric pollution in Madrid (Spain) and its suburban town of Pozuelo de Alarcon showed anthropogenic time-related klf enhancement of tree leaves. We established a significant correlation between metal concentration (leaching) in the leaves with Klf and IRM1T. This relationship was not as high as those found in other studies carried out on airborne dust, sediments and soils. Further analyses pointed out that local humidity played a dual roll, controlling availability of airborne lithogenic dust and the incorporation of trace metals in the leaf tissue, modulating the magnetic enhancement. Further to these findings, the comparison between cities of different climatic regimes showed that air humidity is the major factor controlling the interaction of the atmosphere and tree leaves, thus their magnetic properties. The relative influence of pollutants, lithogenic dust and biological effects depends not only on local meteorology but also on climate. Their influence should be most seriously considered to design methodological approaches that are appropriate to the environmental characteristics of each study area, if the magnetic properties of tree leaves are intended as an atmospheric pollution-monitoring tool.

GIADA onboard Rosetta characterising comet 67/PChuryumov-Gerasimenko dust environment inbound to and outbound from perihelion.

NASA Astrophysics Data System (ADS)

Della Corte, Vincenzo; Rotundi, Alessandra; Fulle, Marco

2016-07-01

GIADA (Grain Impact Analyzer and Dust Accumulator) is an in-situ instrument onboard Rosetta monitoring the dust environment of comet 67P/Churyumov-Gerasimenko. GIADA is composed of 3 sub-systems: 1) the Grain Detection System, based on particle detection through light scattering; 2) the Impact Sensor, measuring particle momentum; 3) the Micro-Balances System, constituted of 5 quartz crystal microbalances, providing cumulated dust from different directions. From the combination of the measurements performed by the three subsystems we retrieve: the number, the mass, the momentum, the speed of individual dust particles and the cumulative dust flux emitted from the comet nucleus. We will present the coma dust environment as observed by GIADA during the pre-landing and escort phases of the Rosetta space mission. GIADA was able to detect temporal and spatial variation of dust density distribution and to disentangle different types of impacting dust particles. Specific high dust spatial density sectors of the coma have been identified and their evolution with respect to the heliocentric distance was studied. From August 2014 to December 2015, i.e. inbound, at and outbound perihelion, Rosetta performed different trajectories around the nucleus and flybys with different close approach distances, different coordinates of the sub-spacecraft point and different observing geometry (phase angle), allowed GIADA to characterize the dust environment within the 67P/C-G coma and its temporal variation. Acknowledgements. GIADA was built by a consortium led by the Univ. Napoli "Parthenope" & INAF- Oss. Astr. Capodimonte, IT, in collaboration with the Inst. de Astrofisica de Andalucia, ES, Selex-ES s.p.a. and SENER. GIADA is presently managed & operated by Ist. di Astrofisica e Planetologia Spaziali-INAF, IT. GIADA was funded and managed by the Agenzia Spaziale Italiana, IT, with a support of the Spanish Ministry of Education and Science MEC, ES. GIADA was developed from a PI proposal supported by the University of Kent; sci. & tech. contribution given by CISAS, IT, Lab. d'Astr. Spat., FR, and Institutions from UK, IT, FR, DE and USA. We thank the RSGS/ESAC, RMOC/ESOC & Rosetta Project/ESTEC for their outstanding work. Science support provided by NASA through the US Rosetta Project managed by JPL/California Institute of Technology. GIADA calibrated data will be available through the ESA's PSA web site.

MEDUSA: The ExoMars experiment for in-situ monitoring of dust and water vapour

NASA Astrophysics Data System (ADS)

Colangeli, L.; Lopez-Moreno, J. J.; Nørnberg, P.; Della Corte, V.; Esposito, F.; Mazzotta Epifani, E.; Merrison, J.; Molfese, C.; Palumbo, P.; Rodriguez-Gomez, J. F.; Rotundi, A.; Visconti, G.; Zarnecki, J. C.; The International Medusa Team

2009-07-01

Dust and water vapour are fundamental components of the Martian atmosphere. 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. Here dust and water vapour have (and have had) strong influence. Of major scientific interest is the quantity and physical, chemical and electrical properties of dust and the abundance of water vapour dispersed in the atmosphere and their exchange with the surface. Moreover, in view of the exploration of the planet with automated systems and in the future by manned missions, it is of primary importance to analyse the hazards linked to these environmental factors. The Martian Environmental Dust Systematic Analyser (MEDUSA) experiment, included in the scientific payload of the ESA ExoMars mission, accommodates a complement of sensors, based on optical detection and cumulative mass deposition, that aims to study dust and water vapour in the lower Martian atmosphere. The goals are to study, for the first time, in-situ and quantitatively, physical properties of the airborne dust, including the cumulative dust mass flux, the dust deposition rate, the physical and electrification properties, the size distribution of sampled particles and the atmospheric water vapour abundance versus time.

Relating Optical Properties of Dusts to their Mineralogical and Physical Interrelationships

NASA Astrophysics Data System (ADS)

Engelbrecht, J. P.; Moosmuller, H.; Jayanty, R. K. M.; Casuccio, G.; Pincock, S. L.

2015-12-01

The purpose of the project was to provide information on the mineralogical, chemical and physical interrelationships of re-suspended mineral dust samples collected as grab samples from global dust sources. Surface soil samples were collected from about 65 desert sites, including the southwestern USA (12), Mali (3), Chad (3), Morocco (1), Canary Islands (8), Cape Verde (1), Djibouti (1), Afghanistan (3), Iraq (6), Kuwait (5), Qatar (1), UAE (1), Serbia (3), China (5), Namibia (3), Botswana (4), Australia (3), and Chile (1). The < 38 μm sieved fraction of each sample was re-suspended in an entrainment chamber, from which the airborne mineral dust could be monitored, sampled and analyzed. Instruments integrated into the entrainment facility included two PM10 and two PM2.5 filter samplers, a beta attenuation gauge for the continuous measurement of PM10 and PM2.5particulate mass fractions, an aerodynamic particle size (APS) analyzer, and a three wavelength (405, 532, 781nm) photoacoustic resonator with integrating reciprocal nephelometer for monitoring absorption and scattering coefficients during the dust re-suspension process. Filter sample media included Teflon® membrane and quartz fiber filters for chemical analysis (71 species), and Nuclepore® filters for individual particle analysis by Scanning Electron Microscopy (SEM). The < 38 μm sieved fractions were also analyzed by X-ray diffraction for their mineral content while the > 38 μm, < 125 μm soil fractions were mineralogically characterized by optical microscopy. We will be presenting results on the optical measurements, also showing the relationship between single scattering albedo (SSA) at three different wavelengths, and chemical as well as mineralogical content and interdependencies of the entrained dust samples. Examples showing the relationships between the single scattering albedos of airborne dusts, and iron (Fe) in hematite, goethite, and clay minerals (montmorillonite, illite, palygorskite), will be discussed. Our goal is to establish a database of the optical, mineralogical, and chemical properties of dust samples collected at multiple global dust sources. These data can be for applications in climate modeling, remote sensing, visibility, health (medical geology), ocean fertilization, and damage to equipment.

Dust Aerosol Particle Size at the Mars Science Laboratory Landing Site

NASA Astrophysics Data System (ADS)

Vicente-Retortillo, Alvaro; Martínez, Germán; Renno, Nilton; Lemmon, Mark; de la Torre-Juárez, Manuel

2017-04-01

We have developed a new methodology to retrieve dust aerosol particle size from Mars Science Laboratory (MSL) observations [1]. We use photodiode output currents measured by the Rover Environmental Monitoring Station (REMS) UV sensor (UVS), ancillary data records (ADR) containing the geometry of the rover and the Sun, and values of the atmospheric opacity retrieved from Mastcam measurements. In particular, we analyze REMS UVS measurements when the Sun is blocked by the masthead and the mast of the rover since the behavior of the output currents during these shadow events depends on the dust phase function, which depends on particle size. The retrieved dust effective radii show a significant seasonal variability, ranging from 0.6 μm during the low opacity season (Ls = 60° - 140°) to 2 μm during the high opacity season (Ls = 180° - 360°). The relationship between atmospheric opacity and dust particle size indicates that dust-lifting events originate at various distances from Gale Crater. The external origin of high dust content events is consistent with the strong and persistent northerly and northwesterly winds at Gale Crater during the perihelion season centered around Ls = 270° [2]. From an interannual perspective, the general behavior of the particle size evolution in MY 31-32 is similar to that in MY 32-33, although some differences are noted. During the low opacity season (Ls = 60° - 140°), the retrieved dust effective radii in MY 33 are significantly lower than in MY 32. A larger contribution of water ice clouds to the total atmospheric opacity during the aphelion season of MY 33 can partially explain such a departure. Differences during the perihelion season are caused by interannual variability of enhanced opacity events. The determination of dust aerosol particle size is important to improve the accuracy of models in simulating the UV environment at the surface [3] and in predicting heating rates, which affect the atmospheric thermal and dynamical fields, and aerosol atmospheric transport, including gravitational settling rates. References: [1] Vicente-Retortillo, A. et al., GRL, submitted. [2] Rafkin, S. et al. (2016), Icarus, 280, 114-138. [3] Webster, C.R., et al. (2016), AGU Fall Meeting.

Classification of Dust Days by Satellite Remotely Sensed Aerosol Products

NASA Technical Reports Server (NTRS)

Sorek-Hammer, M.; Cohen, A.; Levy, Robert C.; Ziv, B.; Broday, D. M.

2013-01-01

Considerable progress in satellite remote sensing (SRS) of dust particles has been seen in the last decade. From an environmental health perspective, such an event detection, after linking it to ground particulate matter (PM) concentrations, can proxy acute exposure to respirable particles of certain properties (i.e. size, composition, and toxicity). Being affected considerably by atmospheric dust, previous studies in the Eastern Mediterranean, and in Israel in particular, have focused on mechanistic and synoptic prediction, classification, and characterization of dust events. In particular, a scheme for identifying dust days (DD) in Israel based on ground PM10 (particulate matter of size smaller than 10 nm) measurements has been suggested, which has been validated by compositional analysis. This scheme requires information regarding ground PM10 levels, which is naturally limited in places with sparse ground-monitoring coverage. In such cases, SRS may be an efficient and cost-effective alternative to ground measurements. This work demonstrates a new model for identifying DD and non-DD (NDD) over Israel based on an integration of aerosol products from different satellite platforms (Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI)). Analysis of ground-monitoring data from 2007 to 2008 in southern Israel revealed 67 DD, with more than 88 percent occurring during winter and spring. A Classification and Regression Tree (CART) model that was applied to a database containing ground monitoring (the dependent variable) and SRS aerosol product (the independent variables) records revealed an optimal set of binary variables for the identification of DD. These variables are combinations of the following primary variables: the calendar month, ground-level relative humidity (RH), the aerosol optical depth (AOD) from MODIS, and the aerosol absorbing index (AAI) from OMI. A logistic regression that uses these variables, coded as binary variables, demonstrated 93.2 percent correct classifications of DD and NDD. Evaluation of the combined CART-logistic regression scheme in an adjacent geographical region (Gush Dan) demonstrated good results. Using SRS aerosol products for DD and NDD, identification may enable us to distinguish between health, ecological, and environmental effects that result from exposure to these distinct particle populations.

A multiyear dust devil vortex survey using an automated search of pressure time series

NASA Astrophysics Data System (ADS)

Jackson, Brian; Lorenz, Ralph

2015-03-01

Dust devils occur in arid climates on the Earth and ubiquitously on Mars, where they likely dominate the supply of atmospheric dust and influence climate. Martian dust devils have been studied with a combination of orbiting and landed spacecraft, while most studies of terrestrial dust devils have involved manned monitoring of field sites, which can be costly both in time and personnel. As an alternative approach, we describe a multiyear in situ survey of terrestrial dust devils using pressure loggers deployed at El Dorado Playa in Nevada, USA, a site known for dust devil activity. Analogous to previous surveys for Martian dust devils, we conduct a posthoc analysis of the barometric data to search for putative dust devil pressure dips using a new automated detection algorithm. We investigate the completeness and false positive rates of our new algorithm and conduct several statistically robust analyses of the resulting population of dips. We also investigate possible seasonal, annual, and spatial variability of the putative dust devil dips, possible correlations with precipitation, and the influence of sample size on the derived population statistics. Our results suggest that large numbers of dips (>1000) collected over multiple seasons are probably required for accurate assessment of the underlying dust devil population. Correlating long-term barometric time series with other data streams (e.g., solar flux measurements from photovoltaic cells) can uniquely elucidate the natures and origins of dust devils, and accurately assessing their influence requires consideration of the full distribution of dust devil properties, rather than average values.

The Tranisiting Dust of Boyajian's Star

NASA Astrophysics Data System (ADS)

Bodman, Eva; Ellis, Tyler G.; Boyajian, Tabetha S.; Wright, Jason

2018-06-01

From May to October of 2017, Boyajian's Star displayed four days-long dips in observed flux, which are referred to as “Elsie,” “Celeste,” “Skara Brae,” and “Angkor” (Boyajian et al. 2018). This Elsie family dip event was monitored with the Las Cumbres Observatory in three bands, B, r', and i'. Looking at each dip individually, we analyze the multi-band photometry for wavelength dependency in dip depth to constrain properties of the transiting material. We find that all of the dips show non-grey extinction and are consistent with optically thin dust. Interpreting the dips as transiting dust clouds, we constrain the properties of the dust grains and find that the average grain radius is <1 micron, assuming silicate composition. This wavelength dependency and grain size is inconsistent with observed properties of the long-term “secular” dimming (Meng et al. 2017), suggesting that the dust causing the dips is from a separate population.

PREFACE: WMO/GEO Expert Meeting On An International Sand And Dust Storm Warning System

NASA Astrophysics Data System (ADS)

Pérez, C.; Baldasano, J. M.

2009-03-01

This volume of IOP Conference Series: Earth and Environmental Science presents a selection of papers that were given at the WMO/GEO Expert Meeting on an International Sand and Dust Storm Warning System hosted by the Barcelona Supercomputing Center - Centro Nacional de Supercomputación in Barcelona (Spain) on 7-9 November 2007 (http://www.bsc.es/wmo). A sand and dust storm (SDS) is a meteorological phenomenon common in arid and semi-arid regions and arises when a gust front passes or when the wind force exceeds the threshold value where loose sand and dust are removed from the dry surface. After aeolian uptake, SDS reduce visibility to a few meters in and near source regions, and dust plumes are transported over distances as long as thousands of kilometres. Aeolian dust is unique among aerosol phenomena: (1) with the possible exception of sea-salt aerosol, it is globally the most abundant of all aerosol species, (2) it appears as the dominating component of atmospheric aerosol over large areas of the Earth, (3) it represents a serious hazard for life, health, property, environment and economy (occasionally reaching the grade of disaster or catastrophic event) and (4) its influence, impacts, complex interactions and feedbacks within the Earth System span a wide range of spatial and temporal scales. From a political and societal point of view, the concern for SDS and the need for international cooperation were reflected after a survey conducted in 2005 by the World Meteorological Organization (WMO) in which more than forty WMO Member countries expressed their interest for creating or improving capacities for SDS warning advisory and assessment. In this context, recent major advances in research - including, for example, the development and implementation of advanced observing systems, the theoretical understanding of the mechanisms responsible for sand and dust storm generation and the development of global and regional dust models - represent the basis for developing applications focusing on societal benefit and risk reduction. However, at present there are interdisciplinary research challenges to overwhelm current uncertainties in order to reach full potential. Furthermore, the community of practice for SDS observations, forecasts and analyses is mainly scientifically based and rather disconnected from potential users. This requires the development of interfaces with operational communities at international and national levels, strongly focusing on the needs of people and factors at risk. The WMO has taken the lead with international partners to develop and implement a Sand and Dust Storm Warning Advisory and Assessment System (SDS-WAS). The history of the WMO SDS-WAS development is as follows. On 12-14 September 2004, an International Symposium on Sand and Dust Storms was held in Beijing at the China Meteorological Agency followed by a WMO Experts Workshop on Sand and Dust Storms. The recommendations of that workshop led to a proposal to create a WMO Sand and Dust Storm Project coordinated jointly with the Global Atmosphere Watch (GAW). This was approved by the steering body of the World Weather Research Programme (WWRP) in 2005. Responding to a WMO survey conducted in 2005, more than forty WMO Member countries expressed interest in participating in activities to improve capacities for more reliable sand and dust storm monitoring, forecasting and assessment. On 31 October to 1 November 2006 in Shanghai, the steering committee of the Sand and Dust Storm Project proposed the development and implementation of a Sand and Dust Storm Warning, Advisory and Assessment System (SDS-WAS). The WMO Secretariat in Geneva formed an ad-hoc Internal Group on SDS-WAS consisting of scientific officers representing WMO research, observations, operational prediction, service delivery and applications programmes such as aviation and agriculture. In May 2007, the 14th WMO Congress endorsed the launching of the SDS-WAS. It also welcomed the strong support of Spain to host a regional centre for the European/African/Middle East node of SDS-WAS and to play a lead role in implementation. In August 2007, the Korean Meteorological Administration hosted the 2nd International Workshop on Sand and Dust Storms highlighting Korean SDS-WAS activities as well as those of Asian regional partners. From 7-9 November 2007, Spain hosted the WMO/GEO Expert Meeting on SDS-WAS at the Barcelona Supercomputing Center. This consultation meeting brought 100 international experts together from research, observation, forecasting and user countries especially in Africa and the Middle East to discuss the way forward in SDS-WAS implementation. The general objective of the WMO/GEO Expert Meeting on an International Sand and Dust Storm Warning System was to discuss and recommend actions needed to develop a global routine SDS-WAS based on integrating numerical SDS prediction and observing systems, and on establishing effective cooperation between data producers and user communities in order to provide SDS-WAS products capable of contributing to the reduction of risks from SDS. The specific objectives were: to identify, present and suggest future real-time observations for forecast verification and dust surveillance: satellite, ground-based remote sensing (passive and active) and in-situ monitoring to present ongoing forecasting activities to discuss and identify user needs: health, air quality, air transport operations, ocean, and others to identify and discuss dust research issues relevant for operational forecast applications to present the concept of SDS-WAS and Regional Centers The meeting was organised around invited presentations and discussions on observations, modelling and users of the SDS-WAS. C Pérez and J M Baldasano Editors INTERNATIONAL STEERING COMMITTEE José María Baldasano (Chairman) - Barcelona Supercomputing Center, Spain Emilio Cuevas - Instituto Nacional de Meteorología, Spain Leonard A Barrie - World Meteorological Organisation, Switzerland Young J Kim - Gwangju Institute of Science and Technology, Korea Menas Kafatos - George Mason University, USA Xiaoye Zhang - Chinese Meteorology Administration, China Slobodan Nickovic - World Meteorological Organisation, Switzerland Carlos Pérez - Barcelona Supercomputing Center, Spain William A Sprigg - University of Arizona, USA Stéphane Alfaro - Université de Paris Val de Marne, France Ina Tegen - Leibniz Institute for Tropospheric Research, Germany Mohamed Mahmoud Eissa - Under-secretary of State for Researches, Egypt Sunling Gong - Environment Canada, Canada Emily Firth - GEO Secretariat, Switzerland LOCAL ORGANISING COMMITTEE José María Baldasano - Barcelona Supercomputing Center, Spain Carlos Pérez - Barcelona Supercomputing Center, Spain Renata Giménez - Barcelona Supercomputing Center, Spain Emilio Cuevas - Instituto Nacional de Meteorología, Spain Slobodan Nickovic - World Meteorological Organisation, Switzerland J M Marcos - Instituto Nacional de Meteorología, Spain Manuel Palomares - Instituto Nacional de Meteorología, Spain Xavier Querol - Consejo Superior de Investigaciones Científicas, Spain Conference photograph

Improving Decision-Making Activities for Meningitis and Malaria

NASA Astrophysics Data System (ADS)

Ceccato, P.; Trzaska, S.; Perez, C.; Kalashnikova, O. V.; del Corral, J.; Cousin, R.; Blumenthal, M. B.; Connor, S.; Thomson, M. C.

2012-12-01

Public health professionals are increasingly concerned about the potential impact that climate variability and change can have on infectious disease. The International Research Institute for Climate and Society (IRI) is developing new products to increase the public health community's capacity to understand, use, and demand the appropriate climate data and climate information to mitigate the public health impacts of climate on infectious disease, in particular Meningitis and Malaria. In this paper we present the new and improved products that have been developed for monitoring dust, temperature, rainfall and vectorial capacity model for monitoring and forecasting risks of Meningitis and Malaria epidemics. We also present how the products have been integrated into a knowledge system (IRI Data Library Map room, SERVIR) to support the use of climate and environmental information in climate-sensitive health decision-making.

40 CFR 464.36 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 0.0257 0.00838 Oil and Grease (for alternate monitoring) 1.43 0.476 (2) Applicable to plants that... Oil and Grease (for alternate monitoring) 1.43 0.476 (c) Dust Collection Scrubber Operations. (1... TTO 2.04 0.664 Oil and Grease (for alternate monitoring) 22.5 7.51 (2) Applicable to plants that are...

40 CFR 464.36 - Pretreatment standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 0.0257 0.00838 Oil and Grease (for alternate monitoring) 1.43 0.476 (2) Applicable to plants that... Oil and Grease (for alternate monitoring) 1.43 0.476 (c) Dust Collection Scrubber Operations. (1... TTO 2.04 0.664 Oil and Grease (for alternate monitoring) 22.5 7.51 (2) Applicable to plants that are...

A Multi-Year Dust Devil Vortex Survey Using an Automated Search of Pressure Time-Series

NASA Astrophysics Data System (ADS)

Jackson, Brian K.; Lorenz, Ralph

2014-11-01

Dust devils occur in arid climates on the Earth and ubiquitously on Mars, where they likely dominate the supply of atmospheric dust and influence climate. Martian dust devils have been studied with a combination of orbiting and landed spacecraft, while most studies of terrestrial dust devils have involved manned monitoring of field sites, which can be costly both in time and personnel. As an alternative approach, we describe a multi-year in-situ survey of terrestrial dust devils using pressure loggers deployed at El Dorado Playa in Nevada, USA, a site known for dust devil activity. Analogous to previous surveys for Martian dust devils, we conduct a post-hoc analysis of the barometric data to search for putative dust devil pressure dips using a new automated detection algorithm. We investigate the completeness and false positive rates of our new algorithm and conduct several statistically robust analyses of the resulting population of dips. We also investigate seasonal, annual, and spatial variability of the putative dust devil dips, possible correlations with precipitation, and the influence of sample size on the derived population statistics. Our results suggest that large numbers of dips (> 1,000) collected over multiple seasons are probably required for accurate assessment of the underlying dust devil population. Correlating long-term barometric time-series with other data streams (e.g., solar flux measurements from photovoltaic cells) can uniquely elucidate the natures and origins of dust devils, and accurately assessing their influence requires consideration of the full distribution of dust devil properties, rather than average values. For example, our results suggest the dust flux from the average terrestrial devil is nearly 1,000 times smaller than the (more representative) population-weighted average flux. If applicable to Martian dust devils, such corrections may help resolve purported discrepancies between the dust fluxes estimated from dust devil studies and those required to maintain the atmospheric dust concentration.

Continuing Long Term Optical and Infrared Reverberation Mapping of 17 Sloan Digital Sky Survey Quasars

NASA Astrophysics Data System (ADS)

Gorjian, Varoujan; Barth, Aaron; Brandt, Niel; Dawson, Kyle; Green, Paul; Ho, Luis; Horne, Keith; Jiang, Linhua; McGreer, Ian; Schneider, Donald; Shen, Yue; Tao, Charling

2018-05-01

Previous Spitzer reverberation monitoring projects searching for UV/optical light absorbed and re-emitted in the IR by dust have been limited to low luminosity active galactic nuclei (AGN) that could potentially show reverberation within a single cycle ( 1 year). Cycle 11-12's two year baseline allowed for the reverberation mapping of 17 high-luminosity quasars from the Sloan Digital Sky Survey Reverberation Mapping project. We continued this monitoring in Cycle 13 and now propose to extend this program in Cycle 14. By combining ground-based monitoring from Pan-STARRS, CFHT, and Steward Observatory telescopes with Spitzer data we have for the first time detected dust reverberation in quasars. By continuing observations with this unqiue combination of resources we should detect reverberation in more objects and reduce the uncertainties for the remaining sources.

The Use of OMPS Near Real Time Products in Volcanic Cloud Risk Mitigation and Smoke/Dust Air Quality Assessments

NASA Astrophysics Data System (ADS)

Seftor, C. J.; Krotkov, N. A.; McPeters, R. D.; Li, J. Y.; Durbin, P. B.

2015-12-01

Near real time (NRT) SO2 and aerosol index (AI) imagery from Aura's Ozone Monitoring Instrument (OMI) has proven invaluable in mitigating the risk posed to air traffic by SO2 and ash clouds from volcanic eruptions. The OMI products, generated as part of NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE) NRT system and available through LANCE and both NOAA's NESDIS and ESA's Support to Aviation Control Service (SACS) portals, are used to monitor the current location of volcanic clouds and to provide input into Volcanic Ash (VA) advisory forecasts. NRT products have recently been developed using data from the Ozone Mapping and Profiler Suite onboard the Suomi NPP platform; they are currently being made available through the SACS portal and will shortly be incorporated into the LANCE NRT system. We will show examples of the use of OMPS NRT SO2 and AI imagery to monitor recent volcanic eruption events. We will also demonstrate the usefulness of OMPS AI imagery to detect and track dust storms and smoke from fires, and how this information can be used to forecast their impact on air quality in areas far removed from their source. Finally, we will show SO2 and AI imagery generated from our OMPS Direct Broadcast data to highlight the capability of our real time system.

Observations from the High Resolution Imaging Science Experiment (HiRISE): Martian dust devils in Gusev and Russell craters

NASA Astrophysics Data System (ADS)

Verba, Circe A.; Geissler, Paul E.; Titus, Timothy N.; Waller, Devin

2010-09-01

Two areas targeted for repeated imaging by detailed High Resolution Imaging Science Experiment (HiRISE) observations allow us to examine morphological differences and monitor seasonal variations of Martian dust devil tracks at two quite different locations. Russell crater (53.3°S, 12.9°E) is regularly imaged to study seasonal processes including deposition and sublimation of CO2 frost. Gusev crater (14.6°S, 175.4°E) has been frequently imaged in support of the Mars Exploration Rover mission. Gusev crater provides the first opportunity to compare “ground truth” orbital observations of dust devil tracks to surface observations of active dust plumes. Orbital observations show that dust devil tracks are rare, forming at a rate <1/110 that of the occurrence of active dust plumes estimated from Spirit's surface observations. Furthermore, the tracks observed from orbit are wider than typical plume diameters observed by Spirit. We conclude that the tracks in Gusev are primarily formed by rare, large dust devils. Smaller dust devils fail to leave tracks that are visible from orbit, perhaps because of limited surface excavation depths. Russell crater displays more frequent, smaller sinuous tracks than Gusev. This may be due to the thin dust cover in Russell, allowing smaller dust devils to penetrate through the bright dust layer and leave conspicuous tracks. The start of the dust devil season and peak activity are delayed in Russell in comparison to Gusev, likely because of its more southerly location. Dust devils in both sites travel in directions consistent with general circulation model (GCM)-predicted winds, confirming a laboratory-derived approach to determining dust devil travel directions based on track morphology.

The thermal infrared radiance properties of dust aerosol over ocean

NASA Astrophysics Data System (ADS)

Hao, Zengzhou; Pan, Delu; Tu, Qianguang; Gong, Fang; Chen, Jianyu

2015-10-01

Asian dust storms, which can long-range transport to ocean, often occur on spring. The present of Asian dust aerosols over ocean makes some difficult for other studies, such as cloud detection, and also take some advantage for ocean, such as take nutrition into the ocean by dry or wet deposition. Therefore, it is important to study the dust aerosol and retrieve the properties of dust from satellite observations that is mainly from the thermal infrared radiance. In this paper, the thermal infrared radiance properties of dust aerosol over ocean are analyzed from MODIS and MTSAT2 observations and Streamer model simulations. By analyzing some line samples and a series of dust aerosol region, it shows that the dust aerosol brightness temperature at 12μm (BT12) is always greater than BT11 and BT8.5, and BT8.5 is general greater than BT11. The brightness temperature different between 11μm and 12μm (BTD11-12) increases with the dust intensity. And the BTD11-12 will become positive when the atmospheric relative humidity is greater than 70%. The BTD11-12 increases gradually with the surface temperature while the effect on BTD11-12 of dust layer temperature is not evident. Those are caused by the transmission of the dust aerosol is different at the two thermal infrared channels. During daytime, dust infrared brightness temperature at mid-infrared bands should reduce the visual radiance, which takes about 25K or less. In general, BT3.7 is greater than BT11 for dust aerosol. Those results are helpful to monitor or retrieve dust aerosol physical properties over ocean from satellite.

Modeling and observations of dust aerosols during the North American Monsoon

NASA Astrophysics Data System (ADS)

Arellano, A. F.; Raman, A.; Brost, J.; Sorooshian, A.

2016-12-01

Intense dust storms during North American Monsoon (NAM) pose a significant threat to local/regional air quality, economy, and public health. Convection-driven storms (or haboobs) in Arizona and in the southwest US have been given far less attention compared to those in Africa and Middle East. Blowing dusts from these haboobs typically lasts for 3-6 hours and accumulate more than 1000 µg m-3 of PM10 in the atmosphere. However, it is not clear whether haboobs are increasing in intensity and/or frequency in Arizona. Here, we address two science questions: 1) Do haboobs impact the observed trends in aerosol abundance in the NAM region?, 2) What are our current capabilities and limitations in understanding, monitoring, and assessing haboobs and their impacts? For 1), we calculated the trends of enhancements in aerosol optical depth (AOD) from Terra MODIS over dust hotspots in the NAM alley and and surrounding region (dust cluster). Both show similar decreasing trends before the monsoon. However, during the monsoon, a decreasing trend in AOD is more prominent in the dust cluster than in NAM alley. We attribute this to an apparent modulation of dust in the NAM alley by haboobs. Despite increase in rainfall during this period, we infer that the increase in dust sources in the NAM alley obscures the decreasing AOD trend. For 2), we conducted simulations simulations of these haboobs using WRF-Chem with GOCART AFWA scheme at convective resolving scales ( 1 km). Our case study for the 5 July 2011 haboob indicate that the downbursts occurred near Tucson and generated diverging high intensity winds, resulting to cold pools propagating towards Phoenix. We find that WRF-Chem captures the timing of the haboob but severely underestimates the magnitude of dust concentrations that reached as high as 2000 µg m-3 at USEPA Phoenix stations. The impact of the haboob was seen as far as 350 km northwest of Phoenix at an altitude of 2-4 km on 6 July. We find two major limitations in our simulations: 1) lack of dynamic high resolution land cover for prescribing dust sources, and 2) lack of observing system capability especially high temporal resolution, remotely-sensed measurements for monitoring and assessment. Future geostationary missions together with synergistic use of current and future expansion of in-situ measurements can improve these limitations.

[Mathematic analysis of risk factors influence on occupational respiratory diseases development].

PubMed

Budkar', L N; Bugaeva, I V; Obukhova, T Iu; Tereshina, L G; Karpova, E A; Shmonina, O G

2010-01-01

Analysis covered 1348 case histories of workers exposed to industrial dust in Urals region. The analysis applied mathematical processing of survival theory and correlation analysis. The authors studied influence of various factors: dust concentration, connective tissue dysplasia, smoking habits--on duration for diseases caused by dust to appear. Findings are that occupational diseases develop reliably faster with higher ambient dust concentrations and with connective tissue dysplasia syndrome. Smoking habits do not alter duration of pneumoconiosis development, but reliably increases development of occupational dust bronchitis.

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

NASA Technical Reports Server (NTRS)

Abbas, Mian M.; Craven, Paul D.; Spann, James F.; Tankosic, Dragana; Six, N. Frank (Technical Monitor)

2002-01-01

A laboratory facility for levitating single isolated dust particles in an electrodynamics balance has been developing at NASA/Marshall Space Flight Center for conducting a variety of experimental, of astrophysical interest. The objective of this research is to employ this innovative experimental technique for studies of the physical and optical properties of the analogs of cosmic grains of 0.2-10 micron size in a chamber with controlled pressure/temperatures simulating astrophysical environments. In particular, we will carry out three classes of experiments to investigate the microphysics of the analogs of interstellar and interplanetary 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. These measurements will provide the much-needed photoelectric emission data relating to individual particles as opposed to that for the bulk materials available so far. (2) Infrared optical properties of dust particles obtained by irradiating the particles with radiation from tunable infrared diode lasers and measuring the scattered radiation. Specifically, the complex refractive indices, the extinction coefficients, the scattering phase functions, and the polarization properties of single dust grains of interest in interstellar environments, in the 1-25 micron spectral region will be determined. (3) Condensation experiments to investigate the deposition of volatile gases on colder nucleated particles in dense interstellar clouds and lower planetary atmospheres. The increase in the mass or m/q ratio 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 wild permit determination of the sticking efficiencies of volatile gases of astrophysical interest. Preliminary results based on photoelectric emission experiments on 0.2-6.6 micron size silica particles exposed to UV radiation in the 120-200 nm spectral region will be presented.

On large-scale transport of dust storms and anthropogenic dust-falls over east Asia observed in central Korea in 2009

NASA Astrophysics Data System (ADS)

Chung, Y. S.; Kim, Hak-Sung; Chun, Youngsin

2014-05-01

Dust air pollution has been routinely monitored in central Korea for the last two decades. In 2009, there were eight typical episodes of significant dust loadings in the air: four were caused by dust storms from deserts in Mongolia and Northern China, while the remaining were typical cases of anthropogenic air pollution masses arriving from the Yellow Sea and East China. These natural dust loadings occurred with cool northwesterly airflows in the forward side of an intense anticyclone coming from Mongolia and Siberia. The mean concentrations of the four natural dustfall cases for TSP, PM10 and PM2.5 were 632, 480 and 100 μg m-3, respectively. In contrast, the anthropogenic dust-pollution episodes occurred with the warm westerly and southwesterly airflows in the rear side of an anticyclone. This produced a favorable atmospheric and chemical condition for the build-up of anthropogenic dust air pollution in the Yellow Sea. The mean concentrations of the four anthropogenic dust loadings for TSP, PM10 and PM2.5 were 224, 187 and 137 μg m-3, respectively. The contents of fine dust loadings of PM2.5 were comparatively high in the cases of anthropogenic air pollution. High atmospheric concentrations of fine particles in the atmosphere cause poor visibility and constitute a health hazard. Satellite observations clearly showed the movement of dust-pollution masses from Mongolia and Northern China and from the Yellow Sea and East China that caused these dust pollution episodes in Korea.

[Status of lead exposure and its impact on health of workers in an accumulator factory].

PubMed

Liang, Jiabin; Zhang, Jian; Guo, Xiaojing; Mai, Jianping; Wang, Zhi; Liu, Yimin

2014-02-01

To identify the occupational hazard factors in an accumulator factory, to analyze the status of internal and external lead exposure and evaluate the impact of lead exposure on the health of workers in the accumulator industry, and to provide a theoretical basis for improved lead exposure criteria and technical support for the control of lead contamination in the accumulator industry. An on-site investigation was carried out to monitor and evaluate the lead fume and dust in the workplaces of an accumulator factory, and occupational health examination was performed in all workers. The occupational hazard safeguards in the accumulator factory were unadvanced. The contamination of lead fume and dust was serious. The abnormal rate of blood lead was up to 79.80%, and many workers developed anemia and mild peripheral nerve disease. Lead contamination is serious in the accumulator factory, leading to poor health of workers. It is essential to take effective control measures, improve the working environment, provide occupational health education, increase workers' self-protection awareness, and periodically conduct occupational hazard monitoring and health surveillance. The government must reinforce occupational health supervision of such enterprises.

Identification of Dust Source Regions at High-Resolution and Dynamics of Dust Source Mask over Southwest United States Using Remote Sensing Data

NASA Astrophysics Data System (ADS)

Sprigg, W. A.; Sahoo, S.; Prasad, A. K.; Venkatesh, A. S.; Vukovic, A.; Nickovic, S.

2015-12-01

Identification and evaluation of sources of aeolian mineral dust is a critical task in the simulation of dust. Recently, time series of space based multi-sensor satellite images have been used to identify and monitor changes in the land surface characteristics. Modeling of windblown dust requires precise delineation of mineral dust source and its strength that varies over a region as well as seasonal and inter-annual variability due to changes in land use and land cover. Southwest USA is one of the major dust emission prone zone in North American continent where dust is generated from low lying dried-up areas with bare ground surface and they may be scattered or appear as point sources on high resolution satellite images. In the current research, various satellite derived variables have been integrated to produce a high-resolution dust source mask, at grid size of 250 m, using data such as digital elevation model, surface reflectance, vegetation cover, land cover class, and surface wetness. Previous dust source models have been adopted to produce a multi-parameter dust source mask using data from satellites such as Terra (Moderate Resolution Imaging Spectroradiometer - MODIS), and Landsat. The dust source mask model captures the topographically low regions with bare soil surface, dried-up river plains, and lakes which form important source of dust in southwest USA. The study region is also one of the hottest regions of USA where surface dryness, land use (agricultural use), and vegetation cover changes significantly leading to major changes in the areal coverage of potential dust source regions. A dynamic high resolution dust source mask have been produced to address intra-annual change in the aerial extent of bare dry surfaces. Time series of satellite derived data have been used to create dynamic dust source masks. A new dust source mask at 16 day interval allows enhanced detection of potential dust source regions that can be employed in the dust emission and transport pathways models for better estimation of emission of dust during dust storms, particulate air pollution, public health risk assessment tools and decision support systems.

Wood dust particle and mass concentrations and filtration efficiency in sanding of wood materials.

PubMed

Welling, Irma; Lehtimäki, Matti; Rautio, Sari; Lähde, Tero; Enbom, Seppo; Hynynen, Pasi; Hämeri, Kaarle

2009-02-01

The importance of fine particles has become apparent as the knowledge of their effects on health has increased. Fine particle concentrations have been published for outside air, plasma arc cutting, welding, and grinding, but little data exists for the woodworking industry. Sanding was evaluated as the producer of the woodworking industry's finest particles, and was selected as the target study. The number of dust particles in different particle size classes and the mass concentrations were measured in the following environments: workplace air during sanding in plywood production and in the inlet and return air; in the dust emission chamber; and in filter testing. The numbers of fine particles were low, less than 10(4) particles/cm(3) (10(7) particles/L). They were much lower than typical number concentrations near 10(6) particles/cm(3) measured in plasma arc cutting, grinding, and welding. Ultrafine particles in the size class less than 100 nm were found during sanding of MDF (medium density fiberboard) sheets. When the cleaned air is returned to the working areas, the dust content in extraction systems must be monitored continuously. One way to monitor the dust content in the return air is to use an after-filter and measure pressure drop across the filter to indicate leaks in the air-cleaning system. The best after-filtration materials provided a clear increase in pressure drop across the filter in the loading of the filter. The best after-filtration materials proved to be quite effective also for fine particles. The best mass removal efficiencies for fine particles around 0.3 mum were over 80% for some filter materials loaded with sanding wood dust.

PM2.5 Source Apportionment: Reconciling Receptor Models for U.S. Nonurban and Urban Long-Term Networks.

PubMed

Chen, L-W Antony; Watson, John G; Chow, Judith C; DuBois, Dave W; Herschberger, Lisa

2011-11-01

Chemical mass balance (CMB) and trajectory receptor models were applied to speciated particulate matter with aerodynamic diameter ≤2.5 μm (PM 2.5 ) measurements from Speciation Trends Network (STN; part of the Chemical Speciation Network [CSN]) and Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring network across the state of Minnesota as part of the Minnesota PM 2.5 Source Apportionment Study (MPSAS). CMB equations were solved by the Unmix, positive matrix factorization (PMF), and effective variance (EV) methods, giving collective source contribution and uncertainty estimates. Geological source profiles developed from local dust materials were either incorporated into the EV-CMB model or used to verify factors derived from Unmix and PMF. Common sources include soil dust, calcium (Ca)-rich dust, diesel and gasoline vehicle exhausts, biomass burning, secondary sulfate, and secondary nitrate. Secondary sulfate and nitrate aerosols dominate PM 2.5 mass (50-69%). Mobile sources outweigh area sources at urban sites, and vice versa at rural sites due to traffic emissions. Gasoline and diesel contributions can be separated using data from the STN, despite significant uncertainties. Major differences between MPSAS and earlier studies on similar environments appear to be the type and magnitude of stationary sources, but these sources are generally minor (<7%) in this and other studies. Ensemble back-trajectory analysis shows that the lower Midwestern states are the predominant source region for secondary ammoniated sulfate in Minnesota. It also suggests substantial contributions of biomass burning and soil dust from out-of-state on occasions, although a quantitative separation of local and regional contributions was not achieved in the current study. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of the Air & Waste Management Association for a summary of input data, Unmix and PMF factor profiles, and additional maps. [Box: see text].

Evaluation of Diffuse Reflection Infrared Spectrometry for End-of-Shift Measurement of α-quartz in Coal Dust Samples

PubMed Central

Miller, Arthur L.; Murphy, Nathaniel C.; Bayman, Sean J.; Briggs, Zachary P.; Kilpatrick, Andrew D.; Quinn, Courtney A.; Wadas, Mackenzie R.; Cauda, Emanuele G.; Griffiths, Peter R.

2015-01-01

The inhalation of toxic substances is a major threat to the health of miners, and dust containing respirable crystalline silica (α-quartz) is of particular concern, due to the recent rise in cases of coal workers’ pneumoconiosis and silicosis in some U.S. mining regions. Currently, there is no field-portable instrument that can measure airborne α-quartz and give miners timely feedback on their exposure. The U.S. National Institute for Occupational Safety and Health (NIOSH) is therefore conducting studies to investigate technologies capable of end-of-shift or real-time measurement of airborne quartz. The present study focuses on the potential application of Fourier transform infrared (FT-IR) spectrometry conducted in the diffuse reflection (DR) mode as a technique for measuring α-quartz in respirable mine dust. A DR accessory was used to analyze lab-generated respirable samples of Min-U-Sil 5 (which contains more than 90% α-quartz) and coal dust, at mass loadings in the ranges of 100–600 μg and 600–5300 μg, respectively. The dust samples were deposited onto three different types of filters, borosilicate fiberglass, nylon, and polyvinyl chloride (PVC). The reflectance, R, was calculated by the ratio of a blank filter and a filter with deposited mine dust. Results suggest that for coal and pure quartz dusts deposited on 37 mm PVC filters, measurements of −log R correlate linearly with known amounts of quartz on filters, with R2 values of approximately 0.99 and 0.94, respectively, for samples loaded up to ~4000 μg. Additional tests were conducted to measure quartz in coal dusts deposited onto the borosilicate fiberglass and nylon filter media used in the NIOSH-developed Personal Dust Monitor (PDM). The nylon filter was shown to be amenable to DR analysis, but quantification of quartz is more accurate when the filter is “free,” as opposed to being mounted in the PDM filter holder. The borosilicate fiberglass filters were shown to produce excessive interference, making quartz quantification impossible. It was concluded that, while the DR/FT-IR method is potentially useful for on-filter measurement of quartz in dust samples, the use of PVC filters produced the most accurate results. PMID:25636081

Evaluation of Diffuse Reflection Infrared Spectrometry for End-of-Shift Measurement of α-quartz in Coal Dust Samples.

PubMed

Miller, Arthur L; Murphy, Nathaniel C; Bayman, Sean J; Briggs, Zachary P; Kilpatrick, Andrew D; Quinn, Courtney A; Wadas, Mackenzie R; Cauda, Emanuele G; Griffiths, Peter R

2015-01-01

The inhalation of toxic substances is a major threat to the health of miners, and dust containing respirable crystalline silica (α-quartz) is of particular concern, due to the recent rise in cases of coal workers' pneumoconiosis and silicosis in some U.S. mining regions. Currently, there is no field-portable instrument that can measure airborne α-quartz and give miners timely feedback on their exposure. The U.S. National Institute for Occupational Safety and Health (NIOSH) is therefore conducting studies to investigate technologies capable of end-of-shift or real-time measurement of airborne quartz. The present study focuses on the potential application of Fourier transform infrared (FT-IR) spectrometry conducted in the diffuse reflection (DR) mode as a technique for measuring α-quartz in respirable mine dust. A DR accessory was used to analyze lab-generated respirable samples of Min-U-Sil 5 (which contains more than 90% α-quartz) and coal dust, at mass loadings in the ranges of 100-600 μg and 600-5300 μg, respectively. The dust samples were deposited onto three different types of filters, borosilicate fiberglass, nylon, and polyvinyl chloride (PVC). The reflectance, R, was calculated by the ratio of a blank filter and a filter with deposited mine dust. Results suggest that for coal and pure quartz dusts deposited on 37 mm PVC filters, measurements of -log R correlate linearly with known amounts of quartz on filters, with R(2) values of approximately 0.99 and 0.94, respectively, for samples loaded up to ∼4000 μg. Additional tests were conducted to measure quartz in coal dusts deposited onto the borosilicate fiberglass and nylon filter media used in the NIOSH-developed Personal Dust Monitor (PDM). The nylon filter was shown to be amenable to DR analysis, but quantification of quartz is more accurate when the filter is "free," as opposed to being mounted in the PDM filter holder. The borosilicate fiberglass filters were shown to produce excessive interference, making quartz quantification impossible. It was concluded that, while the DR/FT-IR method is potentially useful for on-filter measurement of quartz in dust samples, the use of PVC filters produced the most accurate results.

Groundbased monitoring of Martian atmospheric opacity

NASA Technical Reports Server (NTRS)

Herkenhoff, K. E.; Martin, L. J.

1993-01-01

The amount of dust in the Martian atmosphere is variable in both space and time. The presence of aerosols in the Mars atmosphere complicates quantitative analysis of Martian surface properties. We have developed a model for Mars surface and atmospheric scattering based on equations in Hillier et al (1991). This formulation was chosen for its speed of computation and because it accounts for the spherical geometry of atmospheric scattering at high mission angles, i.e., near the planetary limb.

Stardust Sample Collection at Wild 2 and Its Preliminary Examination

NASA Technical Reports Server (NTRS)

Tsou, P.; Brownlee, D. E.; Hoerz, F.; Newburn, R. L.; Sandford, S. A.; Sekanina, Z.; Zolensky, M. E.

2004-01-01

The primary objective of STARDUST is to collect coma samples from 81P/Wild 2. This was made on January 2, 2004. Before the encounter three significant model predictions existed for the number and size of samples to be captured. Three investigations during the Wild 2 encounter (Dust Flux Monitor, Comet and Interstellar Dust Analyzer and Dynamic Science) made in situ measurements of the dust. Spectacular images were captured of the Wild 2 nucleus and dust jets. This abstract compares the model predictions with the in situ measurements and Wild 2 images and assesses the likely samples to be returned for analysis on January 15, 2006. To give some lead time for sample analysts to prepare for the analyses of the returned samples, the organization of the Preliminary Examination is presented.

Do we detect interplanetary dust with Faraday cups?

NASA Astrophysics Data System (ADS)

Kočiščák, S.; Pavlů, J.; Šafránková, J.; Němeček, Z.; Přech, L.

2018-07-01

Transient clouds of a plasma generated by hypervelocity dust particles impacting onto the spacecraft were observed in-situ by many experiments over the last 20 years. The reported observations analyze sensitive measurements of plasma waves that are transmitted to the Earth with a sufficient time resolution. The detection is based on a fact that hypervelocity impacts generate plumes of the ionized gas expanding into a space. The present paper analyzes five years of the operation of the Bright Monitor of the Solar Wind (BMSW) onboard the Spektr-R spacecraft with a motivation to demonstrate that such type of the instruments is capable to observe the dust impacts into its detectors. The results of analysis are compared with Wind electric field measurements used for a detection of hypervelocity dust impacts.

Increasing cardiopulmonary emergency visits by long-range transported Asian dust storms in Taiwan.

PubMed

Chan, Chang-Chuan; Chuang, Kai-Jen; Chen, Wen-Jone; Chang, Wei-Tien; Lee, Chung-Te; Peng, Chi-Ming

2008-03-01

This study aims to explore whether Asian dust storms can affect health after 4000 km long-range transport from their origins to downwind areas. Asian dust storms reaching Taipei, Taiwan are tracked by satellite images and confirmed by backward trajectory analysis and ground air pollution monitoring between 1995 and 2002. Our outcome variables include emergency visits for ischaemic heart diseases (ICD-9-CM 410-411, 414), cerebrovascular diseases (ICD-9-CM 430-437), and chronic obstructive pulmonary diseases (COPD) (ICD-9-CM 493, 496) from the National Taiwan University Hospital (NTUH). We use simple paired t-test and Poisson regression models to compare difference in emergency visits, air pollution levels and meteorological conditions for the pairs of Asian dust events and pre-dust periods. There were 39 high dust events with PM(10) greater than 90 microg/m(3) and another 46 low dust events with PM(10) less than 90 microg/m(3). Compared to their pre-dust periods, PM(10) concentrations are significantly increased by 77 microg/m(3) per event for the high dust events. Asian dust storms increase cardiopulmonary emergency visits during storm-affecting periods in Taipei when ambient PM(10) concentrations are above 90 microg/m(3). Compared to their pre-dust periods, emergency visits for ischaemic heart diseases, cerebrovascular diseases, and COPD during high dust events are increased by 0.7 case (35%), 0.7 case (20%), and 0.9 case (20%) per event, respectively, by paired t-tests. By comparing the model-predicted to the observed emergency visits, we find emergency visits for cardiovascular diseases (ICD-9-CM 410-411, 414, 430-437) were significantly increased by 2.9 cases (67%) per event for the 39 high Asian dust events.

Dust deposition effects on growth and physiology of the endangered Astragalus jaegerianus (Fabaceae)

USGS Publications Warehouse

Wijayratne, Upekala C.; Scoles-Sciulla, Sara J.; Defalco, Lesley A.

2009-01-01

Human expansion into the Mojave Desert is a significant threat to rare desert plants. While immediate habitat loss is often the greatest concern, rare plants situated near areas where soil surfaces experience frequent disturbance may be indirectly impacted when fine particulate dust accumulates on leaf surfaces. Remaining populations of the federally listed Astragalus jaegerianus (Lane Mountain milkvetch) occur on land open to expanding military activities and on adjacent public land with increasing recreational use. This study was initiated to determine whether dust accumulation could decrease the vigor and fitness of A. jaegerianus through reduced growth. Beginning in early May 2004, plants located on Bureau of Land Management (BLM) land were dusted bimonthly at canopy-level dust concentrations ranging from 0 to 32 g/m2, and physiology and growth were monitored until late June when plants senesced. The maximum experimental dust level simulates dust concentrations of Mojave Desert perennials neighboring military activities at a nearby army training center. Average shoot growth declined with increasing dust accumulation, but seasonal net photosynthesis increased. Further investigation of plants grown in a greenhouse supported similar trends. This pattern of greater net photosynthesis with increasing dust accumulation may be explained by higher leaf temperatures of dusted individuals. Ambient dust deposition measured in traps near field plants (May 2004–July 2004) ranged from 0.04–0.17 g/m2/ d, which was well below the lowest level of dust on experimental plants (3.95 g/m2/d). With this low level of ambient deposition, we expect that A. jaegerianus plants in this population were not greatly affected by the dust they receive at the level of recreational use during the study.

a Comparison of Empirical and Inteligent Methods for Dust Detection Using Modis Satellite Data

NASA Astrophysics Data System (ADS)

Shahrisvand, M.; Akhoondzadeh, M.

2013-09-01

Nowadays, dust storm in one of the most important natural hazards which is considered as a national concern in scientific communities. This paper considers the capabilities of some classical and intelligent methods for dust detection from satellite imagery around the Middle East region. In the study of dust detection, MODIS images have been a good candidate due to their suitable spectral and temporal resolution. In this study, physical-based and intelligent methods including decision tree, ANN (Artificial Neural Network) and SVM (Support Vector Machine) have been applied to detect dust storms. Among the mentioned approaches, in this paper, SVM method has been implemented for the first time in domain of dust detection studies. Finally, AOD (Aerosol Optical Depth) images, which are one the referenced standard products of OMI (Ozone Monitoring Instrument) sensor, have been used to assess the accuracy of all the implemented methods. Since the SVM method can distinguish dust storm over lands and oceans simultaneously, therefore the accuracy of SVM method is achieved better than the other applied approaches. As a conclusion, this paper shows that SVM can be a powerful tool for production of dust images with remarkable accuracy in comparison with AOT (Aerosol Optical Thickness) product of NASA.

Monitoring Indoor Exposure to Organophosphate Flame Retardants: Hand Wipes and House Dust

PubMed Central

Hoffman, Kate; Garantziotis, Stavros; Birnbaum, Linda S.

2014-01-01

Background: Organophosphate flame retardants (PFRs) are becoming popular replacements for the phased-out polybrominated diphenyl ether (PBDE) mixtures, and they are now commonly detected in indoor environments. However, little is known about human exposure to PFRs because they cannot be easily measured in blood or serum. Objectives: To investigate relationships between the home environment and internal exposure, we assessed associations between two PFRs, tris(1,3-dichloropropyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP), in paired hand wipe and dust samples and concentrations of their metabolites in urine samples (n = 53). We also assessed short-term variation in urinary metabolite concentrations (n = 11 participants; n = 49 samples). Methods: Adult volunteers in North Carolina, USA, completed questionnaires and provided urine, hand wipe, and household dust samples. PFRs and PBDEs were measured in hand wipes and dust, and bis(1,3-dichloropropyl) phosphate (BDCIPP) and diphenyl phosphate (DPHP), metabolites of TDCIPP and TPHP, were measured in urine. Results: TDCIPP and TPHP were detected frequently in hand wipes and dust (> 86.8%), with geometric mean concentrations exceeding those of PBDEs. Unlike PBDEs, dust TDCIPP and TPHP levels were not associated with hand wipes. However, hand wipe levels were associated with urinary metabolites. Participants with the highest hand wipe TPHP mass, for instance, had DPHP levels 2.42 times those of participants with the lowest levels (95% CI: 1.23, 4.77). Women had higher levels of DPHP, but not BDCIPP. BDCIPP and DPHP concentrations were moderately to strongly reliable over 5 consecutive days (intraclass correlation coefficients of 0.81 and 0.51, respectively). Conclusions: PFR exposures are widespread, and hand-to-mouth contact or dermal absorption may be important pathways of exposure. Citation: Hoffman K, Garantziotis S, Birnbaum LS, Stapleton HM. 2015. Monitoring indoor exposure to organophosphate flame retardants: hand wipes and house dust. Environ Health Perspect 123:160–165; http://dx.doi.org/10.1289/ehp.1408669 PMID:25343780

40 CFR 464.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

....0308 0.01 Oil and grease (for alternate monitoring) 0.259 0.0864 (d) Dust Collection Scrubber...) 0.343 0.129 Total Phenols 0.258 0.09 TTO 0.613 0.2 Oil and grease (for alternate monitoring) 9.01 3...) 12.6 4.74 TTO 18.1 5.91 Oil and grease (for alternate monitoring) 330 110 (g) Melting Furnace...

40 CFR 464.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

....0308 0.01 Oil and grease (for alternate monitoring) 0.259 0.0864 (d) Dust Collection Scrubber...) 0.343 0.129 Total Phenols 0.258 0.09 TTO 0.613 0.2 Oil and grease (for alternate monitoring) 9.01 3...) 12.6 4.74 TTO 18.1 5.91 Oil and grease (for alternate monitoring) 330 110 (g) Melting Furnace...

40 CFR 464.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

....0308 0.01 Oil and grease (for alternate monitoring) 0.259 0.0864 (d) Dust Collection Scrubber...) 0.343 0.129 Total Phenols 0.258 0.09 TTO 0.613 0.2 Oil and grease (for alternate monitoring) 9.01 3...) 12.6 4.74 TTO 18.1 5.91 Oil and grease (for alternate monitoring) 330 110 (g) Melting Furnace...

40 CFR 464.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

....0308 0.01 Oil and grease (for alternate monitoring) 0.259 0.0864 (d) Dust Collection Scrubber...) 0.343 0.129 Total Phenols 0.258 0.09 TTO 0.613 0.2 Oil and grease (for alternate monitoring) 9.01 3...) 12.6 4.74 TTO 18.1 5.91 Oil and grease (for alternate monitoring) 330 110 (g) Melting Furnace...

Looking for Dust-Scattering Light Echoes

NASA Astrophysics Data System (ADS)

Mills, Brianna; Heinz, Sebastian; Corrales, Lia

2018-01-01

Galactic X-ray transient sources such as neutron stars or black holes sometimes undergo an outburst in X-rays. Ring structures have been observed around three such sources, produced by the X-ray photons being scattered by interstellar dust grains along our line of sight. These dust-scattering light echoes have proven to be a useful tool for measuring and constraining Galactic distances, mapping the dust structure of the Milky Way, and determining the dust composition in the clouds producing the echo. Detectable light echoes require a sufficient quantity of dust along our line of sight, as well as bright, short-lived Galactic X-ray flares. Using data from the Monitor of All-Sky X-ray Image (MAXI) on-board the International Space Station, we ran a peak finding algorithm in Python to look for characteristic flare events. Each flare was characterized by its fluence, the integrated flux of the flare over time. We measured the distribution of flare fluences to show how many observably bright flares were recorded by MAXI. This work provides a parent set for dust echo searches in archival X-ray data and will inform observing strategies with current and future X-ray missions such as Athena and Lynx.

Determination of crystalline silica in respirable dust upon occupational exposure for Egyptian workers

PubMed Central

MOHAMED, Sabrein H.; EL-ANSARY, Aida L.; EL-AZIZ, Eman M. Abd

2017-01-01

Crystalline free silica is considered as a lung carcinogen and the occupational exposure to its dust is a health hazard to workers employed in industries that involve ores of mineral dust. In Egypt, thousands of people work under conditions of silica dust exposure exceeding the occupational exposure limit, as a result the monitoring of this occupational exposure to crystalline silica dust is required by government legislation. The assessment of the later is a multi-phase process, depend on workplace measurements, quantitative analyses of samples, and comparison of results with the permissible limits. This study aims to investigate occupational exposure to crystalline silica dust at 22 factories in Egypt with different industrial activities like stone cutting, glass making, ceramic, and sand blasting. Dust samples were collected from work sites at the breathing zone using a personal sampling pump and a size-selective cyclone and analyzed using FTIR. The sampling period was 60–120 min. The results show that the exposure at each of the industrial sectors is very much higher than the current national and international limits, and that lead to a great risk of lung cancer and mortality to workers. PMID:29199263

Dust remobilization tests in DIII-D divertor

NASA Astrophysics Data System (ADS)

Bykov, I.; Rudakov, D.; Moyer, R.; Ratynskaia, S.; Tolias, P.; Deangeli, M.; McLean, A.; Bystrov, K.

2015-11-01

Accumulation of dust on hot surfaces is a safety concern for ITER operation. We studied the life cycle of pre-deposited dust under ITER-relevant conditions by exposing W samples with W, C and Al (surrogate for Be) dust at the outer strike point (OSP) in a few ELMy H-mode discharges using DiMES. The maxima in the dust ejection rate correspond to ELM crashes under both attached and detached OSP conditions, as confirmed by a fast camera monitoring DiMES. SEM mapping of dust before and after exposures shows that >95 % of C and <5 % of metal dust gets remobilized in a few shots. In discharges with detached OSP, remaining Al particles melt and fuse together, forming larger spherical grains. At elevated heat flux with attached OSP, they melt, destruct and fuse with W substrate, which is not thermally affected. In this mode W grains partly melt and adjacent particles can weld together, forming larger asymmetric agglomerates with increased adhesion to the surface. We show that these results are consistent with recent observations from Pilot-PSI. Work supported by the US DOE under DE-FC02-04ER54698, DE-FG02-07ER54917 and DE-AC52-07NA27344.

Optical Dust Characterization in Manned Mars Analogue Research Stations

NASA Technical Reports Server (NTRS)

Bos, B. J.; Krebs, Carolyn (Technical Monitor)

2003-01-01

Martian dust has been identified as a potentially serious hazard to any manned Mars landing mission. NASA and other organizations realize this risk and continue to support Martian dust research through the Matador project led by researchers at the University of Arizona. The Mars Society can contribute to this work by beginning a regimen of monitoring and measuring dust properties at its Mars analogue research stations. These research facilities offer the unique opportunity to study the transport and distribution of dust particles within a crewed habitat supporting active geologic exploration. Information regarding the amount, location and size of dust particles that may accumulate in a Mars habitat will be required to design a real Mars habitat and habitat equipment. Beginning such an effort does not require a large outlay of equipment and can be accomplished using crewmembers experienced with station operations. Various optical techniques, such as dark-field illumination, coupled with image processing algorithms enable the collection of dust grain relative size and frequency information. Such approaches can be applied in several different zones within the research stations to evaluate the various dust reduction and isolation procedures implemented during a particular crew rotation. As the stations simulation fidelity increases, the applicability of such data to a functional Mars lander will increase. This presentation describes the optical equipment and procedures for measuring dust properties in Mars analogue research stations that can be implemented during the next field season.

Dust storms and the risk of asthma admissions to hospitals in Kuwait.

PubMed

Thalib, Lukman; Al-Taiar, Abdullah

2012-09-01

Arid areas in the Arabian Peninsula are one of the largest sources of global dust, yet there is no data on the impact of this on human health. This study aimed to investigate the impact of dust storms on hospital admissions due to asthma and all respiratory diseases over a period of 5 years in Kuwait. A population-based retrospective time series study of daily emergency asthma admissions and admissions due to respiratory causes in public hospitals in Kuwait was analyzed in relation to dust storm events. Dust storm days were defined as the mean daily PM(10)>200 μg/m(3) based on measurements obtained from all six monitoring sites in the country. During the five-year study period, 569 (33.6%) days had dust storm events and they were significantly associated with an increased risk of same-day asthma and respiratory admission, adjusted relative risk of 1.07 (95% CI: 1.02-1.12) and 1.06 (95% CI: 1.04-1.08), respectively. This was particularly evident among children. Dust storms have a significant impact on respiratory and asthma admissions. Evidence is more convincing and robust compared to that from other geographical settings which highlights the importance of public health measures to protect people's health during dust storms and reduce the burden on health services due to dust events. Copyright © 2012 Elsevier B.V. All rights reserved.

Emissions from vehicles, tailpipe and vehicle re-entrained road dust

NASA Astrophysics Data System (ADS)

Zhu, Dongzi

Emissions from transportation are some of the largest sources of urban air pollution. Transportation emissions originate from both the engine-through combustion processes and non-tailpipe re-suspended road dust emissions induced by vehicle travel on unpaved and paved roads. Gaseous and particulate emissions from transportation sources have negative impacts on human health, visibility and may influence the global radiation balance. Fugitive dust emissions originating from vehicle travel on paved and unpaved roads constitute a significant fraction of the PM10 in many areas of the western US impacting their attainment status of National Ambient Air Quality Standards. The research used three novel instrument platforms developed at the Desert Research Institute. The In-Plume Emissions Test Stand (IPETS) was designed to provide characterization of exhaust emissions from in-use individual vehicles or engines by analyzing air as close as 1 m from the exhaust port. Real-world emission factors can be quantified by in-plume measurements and provide more realistic measures for emission inventories, source modeling, and receptor modeling than certification measurements. The Testing Re-entrained Aerosol Kinetic Emissions from Roads (TRAKER) provides an effective alternate approach to the EPA AP-42 road dust emissions estimation techniques by sampling 1000s of km of roads versus isolated 3 m sections. The Portable Deposition Monitoring Platform (PDMP incorporates PM and meteorological instruments to characterize the downwind change in particle concentrations to define depositional losses in different environments. The research outcome provides important knowledge for understanding diesel engine emissions, road dust emissions and aerosol deposition process near road sources.

Fugitive dust emissions from paved road travel in the Lake Tahoe basin.

PubMed

Zhu, Dongzi; Kuhns, Hampden D; Brown, Scott; Gillies, John A; Etyemezian, Vicken; Gertler, Alan W

2009-10-01

The clarity of water in Lake Tahoe has declined substantially over the past 40 yr. Causes of the degradation include nitrogen and phosphorous fertilization of the lake waters and increasing amounts of inorganic fine sediment that can scatter light. Atmospheric deposition is a major source of fine sediment. A year-round monitoring study of road dust emissions around the lake was completed in 2007 using the Testing Re-entrained Aerosol Kinetic Emissions from Roads (TRAKER) system developed at the Desert Research Institute (DRI). Results of this study found that, compared with the summer season, road dust emissions increased by a factor of 5 in winter, on average, and about a factor of 10 when traction control material was applied to the roads after snow events. For winter and summer, road dust emission factors (grams coarse particulate matter [PM10] per vehicle kilometer traveled [g/vkt]) showed a decreasing trend with the travel speed of the road. The highest emission factors were observed on very low traffic volume roads on the west side of the lake. These roads were composed of either a 3/8-in. gravel material or had degraded asphalt. The principle factors influencing road dust emissions in the basin are season, vehicle speed (or road type), road condition, road grade, and proximity to other high-emitting roads. Combined with a traffic volume model, an analysis of the total emissions from the road sections surveyed indicated that urban areas (in particular South Lake Tahoe) had the highest emitting roads in the basin.

Associations of phthalate concentrations in floor dust and multi-surface dust with the interior materials in Japanese dwellings.

PubMed

Ait Bamai, Yu; Araki, Atsuko; Kawai, Toshio; Tsuboi, Tazuru; Saito, Ikue; Yoshioka, Eiji; Kanazawa, Ayako; Tajima, Shuji; Shi, Cong; Tamakoshi, Akiko; Kishi, Reiko

2014-01-15

Phthalates are widely used as plasticizers in numerous products. However, there has been some concern about the various effects they may have on human health. Thus, household phthalate levels are an important public health issue. While many studies have assessed phthalate levels in house dust, the association of these levels with building characteristics has scarcely been examined. The present study investigated phthalate levels in house dust samples collected from the living areas of homes, and examined associations between these phthalate levels and the interior materials. Dust was collected from two portions of the living area: floor dust from the entire floor surface, and multi-surface dust from objects more than 35 cm above the floor. The levels of seven phthalates were measured using gas chromatography/mass spectrometry in selective ion monitoring mode. Phthalate levels were higher in multi-surface dust than in floor dust. Among floor dust samples, those from dwellings with compressed wooden flooring had significantly higher levels of di-iso-butyl phthalate compared to those with other floor materials, while polyvinyl chloride (PVC) flooring was associated with higher di-2-ethylhexyl phthalate (DEHP) levels. Among multi-surface dust samples, higher levels of DEHP and di-iso-nonyl phthalate (DINP) were found in samples from homes with PVC wallpaper than without. The number of PVC interior materials was significantly positively correlated with the levels of DEHP and DINP in multi-surface dust. The phthalate levels in multi-surface dust were associated with the interior surface materials, and those in floor dust were directly related to the flooring materials. Our findings show that when using house dust as an exposure assessment, it is very important to note where the samples were collected from. The present report provides useful information about the association between phthalates and dust inside dwellings, which will assist with establishing public health provisions. © 2013. Published by Elsevier B.V. All rights reserved.

A multidisciplinary approach to trace Asian dust storms from source to sink

NASA Astrophysics Data System (ADS)

Yan, Yan; Sun, Youbin; Ma, Long; Long, Xin

2015-03-01

Tracing the source of dust storm (DS) in mega-cities of northern China currently suffers ambiguities from different approaches including source-sink proxy comparison, air mass back trajectory modeling, and satellite image monitoring. By integrating advantages of all three methods, we present a multidisciplinary approach to trace the provenance of dust fall in Xi'an during the spring season (March to May) of 2012. We collected daily dust fall to calculate dust flux variation, and detected eight DS events with remarkable high flux values based on meteorological comparison and extreme detection algorithm. By combining MODIS images and accompanying real-time air mass back trajectories, we attribute four of them as natural DS events and the other four as anthropogenic DS events, suggesting the importance of natural and anthropogenic processes in supplying long-range transported dust. The primary sources of these DS events were constrained to three possible areas, including the northern Chinese deserts, Taklimakan desert, and Gurbantunggut desert. Proxy comparisons based upon the quartz crystallinity index and oxygen isotope further confirmed the source-to-sink linkage between the natural DS events in Xi'an and the dust emissions from the northern Chinese deserts. The integration of geochemical and meteorological tracing approaches favors the dominant contribution of short-distance transportation of modern dust fall on the Chinese Loess Plateau. Our study shows that the multidisciplinary approach could permit a better source identification of modern dust and should be applied properly for tracing the provenance fluctuations of geological dust deposits.

Swift heavy ion irradiation of interstellar dust analogues. Small carbonaceous species released by cosmic rays

NASA Astrophysics Data System (ADS)

Dartois, E.; Chabot, M.; Pino, T.; Béroff, K.; Godard, M.; Severin, D.; Bender, M.; Trautmann, C.

2017-03-01

Context. Interstellar dust grain particles are immersed in vacuum ultraviolet (VUV) and cosmic ray radiation environments influencing their physicochemical composition. Owing to the energetic ionizing interactions, carbonaceous dust particles release fragments that have direct impact on the gas phase chemistry. Aims: The exposure of carbonaceous dust analogues to cosmic rays is simulated in the laboratory by irradiating films of hydrogenated amorphous carbon interstellar analogues with energetic ions. New species formed and released into the gas phase are explored. Methods: Thin carbonaceous interstellar dust analogues were irradiated with gold (950 MeV), xenon (630 MeV), and carbon (43 MeV) ions at the GSI UNILAC accelerator. The evolution of the dust analogues is monitored in situ as a function of fluence at 40, 100, and 300 K. Effects on the solid phase are studied by means of infrared spectroscopy complemented by simultaneously recording mass spectrometry of species released into the gas phase. Results: Specific species produced and released under the ion beam are analyzed. Cross sections derived from ion-solid interaction processes are implemented in an astrophysical context.

Issues related to dust aerosols in the magnesite industry. I. Chamber exposure.

PubMed

Reichrtová, E; Takác, L

1992-01-01

The present paper is an overview of the experimental research into the effects of flue magnesite dust in the magnesite industry in which the raw material (magnesite) is processed into refractory magnesite clinker. The issues related to dust are divided into two problem areas: a) dust aerosol arising in the process of ore mining and consisting largely of magnesite (MgCO3) and b) dust aerosol originating during ore baking in rotatory furnaces and made up mostly of MgO. Thus, larger groups of people become exposed to these aerosols as a result of solid particles escaping into the atmosphere than in the case of occupational exposure. Experimental research carried out on laboratory animals after chamber exposure provided findings on the deposition, retention and elimination of magnesite dust, on impaired balance between magnesium and calcium leading to damage of biological membranes, on how the immune profile or reproduction and embryogenesis is impacted as well as on the possible interaction with sodium salicylate as a result of an impaired acid base balance. These findings are followed up by evidence produced in the course of biological monitoring (Part II).

Mechanics of aeolian processes: Soil erosion and dust production

NASA Technical Reports Server (NTRS)

Mehrabadi, M. M.

1989-01-01

Aeolian (wind) processes occur as a result of atmosphere/land-surface system interactions. A thorough understanding of these processes and their physical/mechanical characterization on a global scale is essential to monitoring global change and, hence, is imperative to the fundamental goal of the Earth observing system (Eos) program. Soil erosion and dust production by wind are of consequence mainly in arid and semi arid regions which cover 36 percent of the Earth's land surface. Some recent models of dust production due to wind erosion of agricultural soils and the mechanics of wind erosion in deserts are reviewed and the difficulties of modeling the aeolian transport are discussed.

Clinically important respiratory effects of dust exposure and smoking in British coal miners

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

Marine, W.M.; Gurr, D.; Jacobsen, M.

A unique data set of 3380 British coal miners has been reanalyzed with major focus on nonpneumoconiotic respiratory conditions. The aim was to assess the independent contribution of smoking and exposure to respirable dust to clinically significant measures of respiratory dysfunction. Exposure to coal-mine dust was monitored over a 10-yr period. Medical surveys provided estimates of prior dust exposure and recorded respiratory symptoms. Each man's FEV1 was compared with the level predicted for his age and height by an internally derived prediction equation for FEV1. Four respiratory indices were considered at the end of the 10-yr period: FEV1 less thanmore » 80%, chronic bronchitis, chronic bronchitis with FEV1 less than 80%, and FEV1 less than 65%. Results were uniformly incorporated into logistic regression equations for each condition. The equations include coefficients for age, dust, and when indicated, an interaction term for age and dust. Dust-related increases in prevalence of each of the 4 conditions were statistically significant and were similar for smokers and nonsmokers at the mean age (47 yr). There was no evidence that smoking potentiates the effect of exposure to dust. Estimates of prevalences at the mean age of all 4 measures of respiratory dysfunction were greater in smokers. At intermediate and high dust exposure the prevalence of the 4 conditions in nonsmokers approached the prevalence in smokers at hypothetically zero dust exposure. Both smoking and dust exposure can cause clinically important respiratory dysfunction and their separate contributions to obstructive airway disease in coal miners appear to be additive.« less

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.

Development and Validation of a Collocated Exposure Monitoring Methodology using Portable Air Monitors

NASA Astrophysics Data System (ADS)

Li, Z.; Che, W.; Frey, H. C.; Lau, A. K. H.

2016-12-01

Portable air monitors are currently being developed and used to enable a move towards exposure monitoring as opposed to fixed site monitoring. Reliable methods are needed regarding capturing spatial and temporal variability in exposure concentration to obtain credible data from which to develop efficient exposure mitigation measures. However, there are few studies that quantify the validity and repeatability of the collected data. The objective of this study is to present and evaluate a collocated exposure monitoring (CEM) methodology including the calibration of portable air monitors against stationary reference equipment, side-by-side comparison of portable air monitors, personal or microenvironmental exposure monitoring and the processing and interpretation of the collected data. The CEM methodology was evaluated based on application to portable monitors TSI DustTrak II Aerosol Monitor 8530 for fine particulate matter (PM2.5) and TSI Q-Trak model 7575 with probe model 982 for CO, CO2, temperature and relative humidity. Taking a school sampling campaign in Hong Kong in January and June, 2015 as an example, the calibrated side-by-side measured 1 Hz PM2.5 concentrations showed good consistency between two sets of portable air monitors. Confidence in side-by-side comparison, PM2.5 concentrations of which most of the time were within 2 percent, enabled robust inference regarding differences when the monitors measured in classroom and pedestrian during school hour. The proposed CEM methodology can be widely applied in sampling campaigns with the objective of simultaneously characterizing pollutant concentrations in two or more locations or microenvironments. The further application of the CEM methodology to transportation exposure will be presented and discussed.

Dust Propagation and Radiation In the Presence of a Low-level Jet in Central China on March 17, 2010

NASA Astrophysics Data System (ADS)

McDowell, B. K.; Chen, S. H.

2014-12-01

Suspended dust in the air can directly change the energy budget in the atmosphere and at the surface through scattering and absorption of radiation. Thus, dust can potentially modify the development of weather systems. To explore the dust-radiation effects on weather systems, a dust model was developed based on the Weather Research and Forecasting (WRF) model. The calculations of dust processes in the WRF dust model include emission, advection, boundary layer mixing, cumulus mixing, dust-radiation interaction, wet scavenging, and sedimentation. Due to a high vertical spatial resolution near the surface a time splitting method was applied to the calculation of dust sedimentation to relax the numerical time step. The "Hexi Corridor" is the historical name given to a string of oases along the northern slope of the Tibetan Plateau that formed a relatively easy transportation route between eastern China and central Asia. As trade developed over the centuries, this route became known as the Silk Road. This corridor also marks the transition from the relatively flat Gobi desert area in northern China to the elevated mountains of the Tibetan Plateau. These mountains present a southern barrier to the paths of dust storms that develop during spring outbreaks of the Mongolian Cyclone. In March of 2010, a series of dust storms developed in the Gobi Desert north of the Hexi Corridor that transported massive amounts of dust eastward to central and northeastern China, Korea and Japan. On March 17 during this event, a low-level jet developed along the northern perimeter of the Plateau, in alignment with upper level winds and the Hexi Corridor. Over the course of the day, a well-defined short-duration dust plume was emitted in the southern Gobi desert area and was transported over 1300 km in a southeast direction, over the Loess Plateau and into the Gansu Province. In this study, the interactions of synoptic conditions with regional topography that led to the development of the low-level jet are evaluated. A dust model based on the Weather Research and Forecasting Model V3.2.1 is used to investigate the interaction of dust and radiation on air temperatures in and around the plume, dust emission and transport, and the resulting regional radiative forcing in the presence of the low-level jet.

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

KSC-2013-3904

NASA Image and Video Library

2013-11-07

CAPE CANAVERAL, Fla. -- Dust particle experiments are conducted for Electrodynamic Dust Shield for Dust Mitigation project in the Electrostatics and Surface Physics Laboratory in the SwampWorks at NASA's Kennedy Space Center in Florida. The technology works by creating an electric field that propagates out like the ripples on a pond. This could prevent dust accumulation on spacesuits, thermal radiators, solar panels, optical instruments and view ports for future lunar and Mars exploration activities. Electrodynamic dust shield, or EDS, technology is based on concepts originally developed by NASA as early as 1967 and later by the University of Tokyo. In 2003, NASA, in collaboration with the University of Arkansas at Little Rock, started development of the EDS for dust particle removal from solar panels to be used on future missions to the moon, an asteroid or Mars. A flight experiment to expose the dust shields to the space environment currently is under development. For more information, visit: http://www.nasa.gov/content/scientists-developing-ways-to-mitigate-dust-problem-for-explorers/ Photo credit: NASA/Dan Casper

Defense Coastal/Estuarine Research Program (DCERP) Baseline Monitoring Plan

DTIC Science & Technology

2007-09-19

climatological stress (e.g., temperature, drought) and shorter-term air pollutant stress (oxidants and metals ). Heavy metals of fine PM have been...speciation of the fine and coarse PM fractions will allow distinction between different PM sources such as wind blown soil dust, including dust...emitting 12% of the total PM2.5 mass (U.S. EPA, 2004b). Source apportionment modeling of PM2.5 mass concentrations from 24 Speciation Defense Coastal

Fiber-coupled THz spectroscopy for monitoring polymeric compounding processes

NASA Astrophysics Data System (ADS)

Vieweg, N.; Krumbholz, N.; Hasek, T.; Wilk, R.; Bartels, V.; Keseberg, C.; Pethukhov, V.; Mikulics, M.; Wetenkamp, L.; Koch, M.

2007-06-01

We present a compact, robust, and transportable fiber-coupled THz system for inline monitoring of polymeric compounding processes in an industrial environment. The system is built on a 90cm x 90cm large shock absorbing optical bench. A sealed metal box protects the system against dust and mechanical disturbances. A closed loop controller unit is used to ensure optimum coupling of the laser beam into the fiber. In order to build efficient and stable fiber-coupled antennas we glue the fibers directly onto photoconductive switches. Thus, the antenna performance is very stable and it is secured from dust or misalignment by vibrations. We discuss fabrication details and antenna performance. First spectroscopic data obtained with this system is presented.

Brominated and phosphate flame retardants (FRs) in indoor dust from different microenvironments: Implications for human exposure via dust ingestion and dermal contact.

PubMed

Zheng, Xiaobo; Qiao, Lin; Covaci, Adrian; Sun, Runxia; Guo, Huiying; Zheng, Jing; Luo, Xiaojun; Xie, Qilai; Mai, Bixian

2017-10-01

Indoor dust has been widely used to monitor flame retardants (FRs) in indoor environment, but most studies only focused on floor dust. In the present study, FRs were examined in indoor dust from different locations. Dust from air conditioner (AC) filters, beddings, floor, and windows in bedrooms, and dust from AC filters, printer table surface, computer table surface, floor, and windows in offices were collected, respectively. Polybrominated diphenyl ether congener 209 (BDE 209) and decabromodiphenyl ethane (DBDPE) were the most abundant brominated flame retardants (BFRs), and tris(chloroisopropyl) phosphate (TCIPP), tris(1,3-dichloroisopropyl) phosphate (TDCIPP), and triphenyl phosphate (TPHP) were the most abundant phosphate flame retardants (PFRs). In bedrooms, the AC filter dust had the highest median levels of BDE 209 (536 ng/g) and DBDPE (2720 ng/g), while bed dust had the highest median levels of ΣPFRs (2750 ng/g) among dust samples. In offices, printer table dust had higher median levels of BDE 209 (1330 ng/g), DBDPE (8470 ng/g), and ΣPFRs (11,000 ng/g) than those in other dust samples. The high dust ingestion values of BDE 209, DBDPE, and individual PFR were 0.28, 1.20, and <0.01-0.32 ng/kg bw/day and 7.37, 31.2, and <0.01-4.54 ng/kg bw/day for BDE 209, DBDPE, and individual PFR for adults and toddlers, respectively. The high dermal exposure values of individual PFR during sleeping were <0.01-0.23 and <0.01-0.36 ng/kg bw/day for adults and toddlers, respectively. More human exposure pathways other than dust ingestion should be considered, such as the dermal contact with beddings and furniture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial and temporal variability in desert dust and anthropogenic pollution in Iraq, 1997-2010.

PubMed

Chudnovsky, A Alexandra; Koutrakis, Petros; Kostinski, Alex; Proctor, Susan P; Garshick, Eric

2017-01-01

Satellite imaging has emerged as a method for monitoring regional air pollution and detecting areas of high dust concentrations. Unlike ground observations, continuous data monitoring is available with global coverage of terrestrial and atmospheric components. In this study we test the utility of different sources of satellite data to assess air pollution concentrations in Iraq. SeaWiFS and MODIS Deep Blue (DB) aerosol optical depth (AOD) products were evaluated and used to characterize the spatial and temporal pollution levels from the late 1990s through 2010. The AOD and Ångström exponent (an indicator of particle size, since smaller Ångström exponent values reflect a source that includes larger particles) were correlated on 50 × 50 km spatial resolution. Generally, AOD and Ångström exponent were inversely correlated, suggesting a significant contribution of coarse particles from dust storms to AOD maxima. Although the majority of grid cells exhibited this trend, a weaker relationship in other locations suggested an additional contribution of fine particles from anthropogenic sources. Tropospheric NO 2 densities from the OMI satellite were elevated over cities, also consistent with a contribution from anthropogenic sources. Our analysis demonstrates the use of satellite imaging data to estimate relative pollution levels and source contributions in areas of the world where direct measurements are not available. The authors demonstrated how satellite data can be used to characterize exposures to dust and to anthropogenic pollution for future health related studies. This approach is of a great potential to investigate the associations between subject-specific exposures to different pollution sources and their health effects in inaccessible regions and areas where ground monitoring is unavailable.

Spatial and temporal variability in desert dust and anthropogenic pollution in Iraq, 1997–2010

PubMed Central

Chudnovsky, A. Alexandra; Koutrakis, Petros; Kostinski, Alex; Proctor, Susan P.; Garshick, Eric

2016-01-01

Satellite imaging has emerged as a method for monitoring regional air pollution and detecting areas of high dust concentrations. Unlike ground observations, continuous data monitoring is available with global coverage of terrestrial and atmospheric components. In this study we test the utility of different sources of satellite data to assess air pollution concentrations in Iraq. SeaWiFS and MODIS Deep Blue (DB) aerosol optical depth (AOD) products were evaluated and used to characterize the spatial and temporal pollution levels from the late 1990s through 2010. The AOD and Ångström exponent (an indicator of particle size, since smaller Ångström exponent values reflect a source that includes larger particles) were correlated on 50 × 50 km spatial resolution. Generally, AOD and Ångström exponent were inversely correlated, suggesting a significant contribution of coarse particles from dust storms to AOD maxima. Although the majority of grid cells exhibited this trend, a weaker relationship in other locations suggested an additional contribution of fine particles from anthropogenic sources. Tropospheric NO2 densities from the OMI satellite were elevated over cities, also consistent with a contribution from anthropogenic sources. Our analysis demonstrates the use of satellite imaging data to estimate relative pollution levels and source contributions in areas of the world where direct measurements are not available. Implications The authors demonstrated how satellite data can be used to characterize exposures to dust and to anthropogenic pollution for future health related studies. This approach is of a great potential to investigate the associations between subject-specific exposures to different pollution sources and their health effects in inaccessible regions and areas where ground monitoring is unavailable. PMID:28001122

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

NASA Astrophysics Data System (ADS)

Zobeck, T. M.; Baddock, M. C.; van Pelt, R.; Fredrickson, E. L.

2009-12-01

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 dust emissions from a bare, fine-textured playa surface located in the Chihuahua Desert at the Jornada Experimental Range, near Las Cruces, New Mexico, USA. We tested natural, undisturbed crusted surfaces and surfaces that had been subjected to two levels of domestic animal disturbance. The animal disturbance was provided by trampling produced from one and ten passes along the length of the wind tunnel by a 630 kg Angus-Hereford cross cow. The trampling broke the durable crust and created loose erodible material. Each treatment (natural crust, one pass, and ten passes) was replicated three times. A push-type wind tunnel with a 6 m long, 0.5 m wide, and 1 m high test section was used to generate dust emissions under controlled conditions. Clean medium sand was dropped onto the playa surface to act as an abrader material. The tunnel wind speed was equivalent to 15 m/s at a height of 2 m over a smooth soil surface. The tunnel was initially run for ten minutes, with no abrader added. A second 30 minute run was subsequently sampled as abrader was added to the wind stream. Dust and saltating material were collected using an isokinetic slot sampler at the end of the tunnel. Total airborne dust was collected on two 25 cm x 20 cm glass fiber filters (GFF) and measured using a GRIMM particle monitor every 6 sec throughout each test run. Disturbance by trampling generated increased saltating material and airborne dust. The amount of saltating material measured during the initial (no abrader added) run was approximately 70% greater and 5.8 times the amount of saltating material measured on the one pass and ten pass plots, respectively, compared with that observed on the undisturbed plots. The total amount of dust measured during the initial (no abrader added) run on GFF for the one pass and ten pass plots was almost twice and three times, respectively, that observed on the undisturbed plots. The ten pass treatment generated about 75% more PM10 dust, as measured by the GRIMM particle monitor, than the undisturbed plots during the 30 minute abrader run.

Dust fallout in Kuwait city: deposition and characterization.

PubMed

Al-Awadhi, Jasem M; Alshuaibi, Arafat A

2013-09-01

Dust fallouts in Kuwait city was monitored on monthly basis during the period from March 2011 to February 2012 at 10 locations. The results of this study reveal that: (1) monthly dust deposition rates ranged from 0.002 to 0.32 kg/m(2) with average deposition rate of 0.053 kg/m(2) and annual average deposition rate of 0.59 kg/m(2), ranking the first out of 56 dust deposition rates observed throughout the world; (2) on average, about 55.9% of the settled dust have fine to very fine sand fraction sizes, while silt and clay comprise an average of 37.4 and 1.4% of the total sample, respectively; (3) the concentrations for Zn and Mo out of 15 other elements analyzed from the dust were up to 11 times higher than their soil background values in Kuwait, while Pb and Ni were about seven times higher; (4) Mo, Ni, Pb and Zn show maximum enrichment relative to the upper continental crustal component (Mn); (5) Sr, Zr and Zn show highest concretions among all collected samples; and (6) quartz and calcite were the dominant minerals in the dust samples. The distribution of the heavy metals in dust seems to be controlled mainly by the land uses and the volume of traffic emissions. Copyright © 2013 Elsevier B.V. All rights reserved.

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.

Martian Magnets Under the Microscope

NASA Technical Reports Server (NTRS)

2004-01-01

NASA's Mars Exploration Rover Spirit acquired this microscopic imager view of its capture magnet on sol 92 (April 6, 2004). Both Spirit and the Mars Exploration Rover Opportunity are equipped with a number of magnets. The capture magnet, as seen here, has a stronger charge than its sidekick, the filter magnet. The lower-powered filter magnet captures only the most magnetic airborne dust with the strongest charges, while the capture magnet picks up all magnetic airborne dust.

The magnets' primary purpose is to collect the martian magnetic dust so that scientists can analyze it with the rovers' Moessbauer spectrometers. While there is plenty of dust on the surface of Mars, it is difficult to confirm where it came from, and when it was last airborne. Because scientists are interested in learning about the properties of the dust in the atmosphere, they devised this dust-collection experiment.

The capture magnet is about 4.5 centimeters (1.8 inches) in diameter and is constructed with a central cylinder and three rings, each with alternating orientations of magnetization. Scientists have been monitoring the continual accumulation of dust since the beginning of the mission with panoramic camera and microscopic imager images. They had to wait until enough dust accumulated before they could get a Moessbauer spectrometer analysis. The results of that analysis, performed on sol 92, have not been sent back to Earth yet.

Definition of yearly emission factor of dust and greenhouse gases through continuous measurements in swine husbandry

NASA Astrophysics Data System (ADS)

Costa, Annamaria; Guarino, Marcella

The object of this study was to develop an accurate estimation method to evaluate the contribution of the various compartments of swine husbandry to dust and GHG (greenhouse gases, CO 2, CH 4 and N 2O) emission into the atmosphere during one year of observation. A weaning, a gestation, a farrowing and a fattening room in an intensive pig house were observed in three different periods (Autumn-Winter, Springtime and Summer, monitoring at least 60% of each period (20% at the beginning, in the middle and at the end) of each cycle). During monitoring, live weight, average live weight gain, number of animals and its variation, type of feed and feeding time were taken into account to evaluate their influence on PM 10, or the fraction of suspended particulate matter with an aerodynamic diameter less than or equal to 10 μm [Emission Inventory Guidebook, 2007. B1100 Particle Emissions from Animal Husbandry Activities. Available from: (accessed October 2008)] and to define GHG emission. The selected piggery had a ventilation control system using a free running impeller to monitor continuously real-time environmental and management parameters with an accuracy of 5%. PM 10 concentration was monitored by a sampler (Haz Dust EPAM 5000), either continuously or through traditional gravimetric technique, and the mean value of dust amount collected on the membranes was utilized as a correction factor to be applied to continuously collected data. PM 10 concentration amount incoming from inlets was removed from PM 10 emission calculation, to estimate the real contribution of pig house dust pollution into atmosphere. Mean yearly emission factor of PM 10 was measured in 2 g d -1 LU -1 for the weaning room, 0.09 g d -1 LU -1 for the farrowing room, 2.59 g d -1 LU -1 for the fattening room and 1.23 g d -1 LU -1 for the gestation room. The highest PM 10 concentration and emission per LU was recorded in the fattening compartment while the lowest value was recorded in the farrowing room. CO 2, CH 4 and N 2O concentrations were continuously measured in the exhaust ducts using an infrared photoacoustic detector IPD (Brüel & Kjaer, Multi-gas Monitor Type 1302, Multipoint Sampler and Doser Type 1303) sampling data every 15 min, for the 60% of the cycles. Yearly emission factor for CO 2 was measured in 5997 g d -1 LU -1 for the weaning room, 1278 g d -1 LU -1 for the farrowing room, 13,636 g d -1 LU -1 for the fattening room and 8851 g d -1 LU -1 for the gestation room. Yearly emission factor for CH 4 was measured in 24.57 g d -1 LU -1 for the weaning room, 4.68 g d -1 LU -1 for the farrowing room, 189.82 g d -1 LU -1 for the fattening room and 132.12 g d -1 LU -1 for the gestation room. Yearly emission factor for N 2O was measured in 3.62 g d -1 LU -1 for the weaning room, 0.66 g d -1 LU -1 for the farrowing room, 3.26 g d -1 LU -1 for the fattening room and 2.72 g d -1 LU -1 for the gestation room.

A System Based on the Internet of Things for Real-Time Particle Monitoring in Buildings

PubMed Central

Roque Ferreira, Cristina; Pitarma, Rui

2018-01-01

Occupational health can be strongly influenced by the indoor environment as people spend 90% of their time indoors. Although indoor air quality (IAQ) is not typically monitored, IAQ parameters could be in many instances very different from those defined as healthy values. Particulate matter (PM), a complex mixture of solid and liquid particles of organic and inorganic substances suspended in the air, is considered the pollutant that affects more people. The most health-damaging particles are the ≤PM10 (diameter of 10 microns or less), which can penetrate and lodge deep inside the lungs, contributing to the risk of developing cardiovascular and respiratory diseases, as well as of lung cancer. This paper presents an Internet of Things (IoT) system for real-time PM monitoring named iDust. This system is based on a WEMOS D1 mini microcontroller and a PMS5003 PM sensor that incorporates scattering principle to measure the value of particles suspended in the air (PM10, PM2.5, and PM1.0). Through a Web dashboard for data visualization and remote notifications, the building manager can plan interventions for enhanced IAQ and ambient assisted living (AAL). Compared to other solutions the iDust is based on open-source technologies, providing a total Wi-Fi system, with several advantages such as its modularity, scalability, low cost, and easy installation. The results obtained are very promising, representing a meaningful tool on the contribution to IAQ and occupational health. PMID:29690534

A System Based on the Internet of Things for Real-Time Particle Monitoring in Buildings.

PubMed

Marques, Gonçalo; Roque Ferreira, Cristina; Pitarma, Rui

2018-04-21

Occupational health can be strongly influenced by the indoor environment as people spend 90% of their time indoors. Although indoor air quality (IAQ) is not typically monitored, IAQ parameters could be in many instances very different from those defined as healthy values. Particulate matter (PM), a complex mixture of solid and liquid particles of organic and inorganic substances suspended in the air, is considered the pollutant that affects more people. The most health-damaging particles are the ≤PM 10 (diameter of 10 microns or less), which can penetrate and lodge deep inside the lungs, contributing to the risk of developing cardiovascular and respiratory diseases, as well as of lung cancer. This paper presents an Internet of Things (IoT) system for real-time PM monitoring named iDust. This system is based on a WEMOS D1 mini microcontroller and a PMS5003 PM sensor that incorporates scattering principle to measure the value of particles suspended in the air (PM 10 , PM 2.5 , and PM 1.0 ). Through a Web dashboard for data visualization and remote notifications, the building manager can plan interventions for enhanced IAQ and ambient assisted living (AAL). Compared to other solutions the iDust is based on open-source technologies, providing a total Wi-Fi system, with several advantages such as its modularity, scalability, low cost, and easy installation. The results obtained are very promising, representing a meaningful tool on the contribution to IAQ and occupational health.

KSC-2013-3902

NASA Image and Video Library

2013-11-07

CAPE CANAVERAL, Fla. -- Dr. Carlos Calle, senior research scientist on the Electrodynamic Dust Shield for Dust Mitigation project, works with dust fabricated for use in his experiments in the Electrostatics and Surface Physics Laboratory in the SwampWorks at NASA's Kennedy Space Center in Florida. The fabricated material is designed to mimic the dust on the lunar surface. The technology works by creating an electric field that propagates out like the ripples on a pond. This could prevent dust accumulation on spacesuits, thermal radiators, solar panels, optical instruments and view ports for future lunar and Mars exploration activities. Electrodynamic dust shield, or EDS, technology is based on concepts originally developed by NASA as early as 1967 and later by the University of Tokyo. In 2003, NASA, in collaboration with the University of Arkansas at Little Rock, started development of the EDS for dust particle removal from solar panels to be used on future missions to the moon, an asteroid or Mars. A flight experiment to expose the dust shields to the space environment currently is under development. For more information, visit: http://www.nasa.gov/content/scientists-developing-ways-to-mitigate-dust-problem-for-explorers/ Photo credit: NASA/Dan Casper

KSC-2013-3900

NASA Image and Video Library

2013-11-07

CAPE CANAVERAL, Fla. -- Dr. Carlos Calle, senior research scientist on the Electrodynamic Dust Shield for Dust Mitigation project, manages the Electrostatics and Surface Physics Laboratory in the SwampWorks at NASA's Kennedy Space Center in Florida. Electrodynamic dust shield, or EDS, technology is based on concepts originally developed by NASA as early as 1967 and later by the University of Tokyo. In 2003, NASA, in collaboration with the University of Arkansas at Little Rock, started development of the EDS for dust particle removal from solar panels to be used on future missions to the moon, an asteroid or Mars. A flight experiment to expose the dust shields to the space environment currently is under development. For more information, visit: http://www.nasa.gov/content/scientists-developing-ways-to-mitigate-dust-problem-for-explorers/ Photo credit: NASA/Dan Casper

40 CFR 63.1651 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... continuously monitor relative particulate matter loadings. Capture system means the equipment (including hoods... due to wind or mechanical inducement such as vehicle traffic. Fugitive dust sources include plant...

40 CFR 63.1651 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... continuously monitor relative particulate matter loadings. Capture system means the equipment (including hoods... due to wind or mechanical inducement such as vehicle traffic. Fugitive dust sources include plant...

40 CFR 63.1651 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... continuously monitor relative particulate matter loadings. Capture system means the equipment (including hoods... due to wind or mechanical inducement such as vehicle traffic. Fugitive dust sources include plant...

Legal immigrants: invasion of alien microbial communities during winter occurring desert dust storms.

PubMed

Weil, Tobias; De Filippo, Carlotta; Albanese, Davide; Donati, Claudio; Pindo, Massimo; Pavarini, Lorenzo; Carotenuto, Federico; Pasqui, Massimiliano; Poto, Luisa; Gabrieli, Jacopo; Barbante, Carlo; Sattler, Birgit; Cavalieri, Duccio; Miglietta, Franco

2017-03-10

A critical aspect regarding the global dispersion of pathogenic microorganisms is associated with atmospheric movement of soil particles. Especially, desert dust storms can transport alien microorganisms over continental scales and can deposit them in sensitive sink habitats. In winter 2014, the largest ever recorded Saharan dust event in Italy was efficiently deposited on the Dolomite Alps and was sealed between dust-free snow. This provided us the unique opportunity to overcome difficulties in separating dust associated from "domestic" microbes and thus, to determine with high precision microorganisms transported exclusively by desert dust. Our metagenomic analysis revealed that sandstorms can move not only fractions but rather large parts of entire microbial communities far away from their area of origin and that this microbiota contains several of the most stress-resistant organisms on Earth, including highly destructive fungal and bacterial pathogens. In particular, we provide first evidence that winter-occurring dust depositions can favor a rapid microbial contamination of sensitive sink habitats after snowmelt. Airborne microbial depositions accompanying extreme meteorological events represent a realistic threat for ecosystem and public health. Therefore, monitoring the spread and persistence of storm-travelling alien microbes is a priority while considering future trajectories of climatic anomalies as well as anthropogenically driven changes in land use in the source regions.

Comparison, association, and risk assessment of phthalates in floor dust at different indoor environments in Delaware, USA.

PubMed

Bi, Xiaolong; Yuan, Shoujun; Pan, Xiaojun; Winstead, Cherese; Wang, Qiquan

2015-01-01

This study aimed to compare and assess phthalate contamination in various indoor environments. In this study, 44 floor dust samples from different indoor environments in Delaware, USA were collected and analyzed for 14 phthalates using gas chromatography-mass spectrometry. Phthalates were detected in all dust samples with the total concentration ranging from 84 to 7117 mg kg(-1). DEHP (di-2-ethylhexyl phthalate), BzBP (benzylbutyl phthalate), DBP (dibutyl phthalate), and DiBP (di-isobutyl phthalate) were both the most frequently and abundantly detected phthalates. The average concentration of total phthalates in dust from offices, student dorms, gyms, stores, and daycare centers was found to be significantly or insignificantly (P = 0.05) higher than that in dust from houses and apartments. Plastic flooring materials and the application of floor care chemical products were positively associated with total phthalate concentration in floor dust. Toxicological risk assessment indicated that an investigated daycare center in this study was the only indoor environment that may cause the intake amount of DEHP of infants, toddlers, and children via dust ingestion to exceed the reference dose established by the U.S. Environmental Protection Agency (USEPA). Regular monitoring on phthalate contamination in sensitive indoor environments is recommended.

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.

Characterization and Modeling of Dust Emissions from an Instrumented Mine Tailings Site

NASA Astrophysics Data System (ADS)

Betterton, E. A.; Stovern, M.; Saez, A.; Csavina, J. L.; Felix Villar, O. I.; Field, J. P.; Rine, K. P.; Russell, M. R.; Saliba, P.

2012-12-01

Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of contaminants from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. We report on the chemical characterization of atmospheric dust and aerosol sampled near the mine tailings. Instrumented eddy flux towers were also setup on the mine tailings to give both spatial and temporal dust observations. The eddy flux towers have multiple DUSTTRAK monitors as well as weather stations. These in situ observations allow us to assess spatial distribution of suspended particulate. Using the DUSTTRAK flux tower observations at 10-second resolution in conjunction with a computational fluid dynamics model, we have been able to model dust transport from the mine tailings to downwind areas. In order to improve the accuracy of the dust transport simulations both regional topographical features and local weather patterns have been incorporated into the model simulations.

Young Stellar Variability of GM Cephei by Circumstellar Dust Clumps

NASA Astrophysics Data System (ADS)

Huang, Po-Chieh; Chen, Wen-Ping; Hu, Chia-Ling; Burkhonov, Otabek; Ehgamberdiev, Shuhrat; Liu, Jinzhong; Naito, Hiroyuki; Pakstiene, Erika; Qvam, Jan Kare Trandem; Rätz, Stefanie; Semkov, Evgeni

2018-04-01

UX Orionis stars are a sub-type of Herbig Ae/be or T Tauri stars exhibiting sporadic extinction of stellar light due to circumstellar dust obscuration. GM Cep is such an UX Orionis star in the young (∼ 4 Myr) open cluster Trumpler 37 at ∼ 900 pc, showing a prominent infrared access, H-alpha emission, and flare activity. Our multi-color photometric monitoring from 2009 to 2016 showed (i) sporadic brightening on a time scale of days due to young stellar accretion, (ii) cyclic, but not strictly periodical, occultation events, each lasting for a couple months, with a probable recurrence time of about two years, (iii) normal dust reddening as the star became redder when dimmer, (iv) the unusual "blueing" phenomena near the brightness minima, during which the star appeared bluer when dimmer, and (v) a noticeable polarization, from 3 to 9 percent in g', r', and i' -bands. The occultation events may be caused by dust clumps, signifying the density inhomogeneity in a young stellar disk from grain coagulation to planetesimal formation. The level of polarization was anti-correlated with the brightness in the bright state, when the dust clump backscattered stellar light. We discussed two potential hypotheses: orbiting dust clumps versus dust clumps along a spiral arm structure.

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.

Experimental Study of Lunar Dust Transportation due to Electrostatic Forces and Micro-meteorite Impacts

NASA Astrophysics Data System (ADS)

Orger, N. C.; Toyoda, K.; Cho, M.

2017-12-01

Lunar dust particles can be transported via several physical mechanisms above the surface, and the electrostatic dust lofting was suspected to be the responsible mechanism for the high-altitude lunar horizon glow above the terminator region. Most of the recent studies have shown that contact forces acting on the dust grains of sub-micrometer and micrometer sizes are much larger than the electrostatic forces resulting from the ambient plasma conditions; however, the electrostatic forces are strong enough to accelerate the lunar dust grains to high altitudes once the dust particles are separated from the surface by an initial mechanism. In this study our purpose is to investigate if the dust particles can be transported under the electrostatic forces after they are released from the surface by the micrometeorite impacts. It is expected to be the most of the dust grains will be launched from the elastic deformation regions, and the contact forces will be canceled after they are moved tens of nanometers. For the experiments, silica particles are used in a cavity with 2 cm diameter and 5 mm depth on the graphite plates. First, the dust particles are baked under an infrared lamp to release the absorbed atmospheric particles in the vacuum chamber. Second, the electron beam source emits electrons with 100 - 200 eV energies, and a Faraday cup measures the electron current in the vacuum chamber. Third, a laser beam is used to simulate micro-meteorite impacts, and the results are monitored with a high speed camera mostly focusing on the elastic deformation region. Therefore, this study investigates how the impacts modify the dust transportation as an initial mechanism for electrostatic dust lofting to high altitudes.

The Cassini Cosmic Dust Analyser CDA - A 10 year exploration of Saturn's dust environment

NASA Astrophysics Data System (ADS)

Srama, Ralf

2014-05-01

The interplanetary space probe Cassini/Huygens reached Saturn in July 2004 after seven years of cruise phase. Since then, the German-lead Cosmic Dust Analyser (CDA) was operated continuously for 10 years in orbit around Saturn. The first discovery of CDA related to Saturn was the measurement of nanometer sized dust particles ejected by its magnetosphere to interplanetary space with speeds higher than 100 km/s. Their origin and composition was analysed and an their dynamical studies showed a strong link to the conditions of the solar wind plasma flow. A recent surprising result was, that stream particles stem from the interior of Enceladus. Since 2004 CDA measured millions of dust impacts characterizing the dust environment of Saturn. The instrument showed strong evidence for ice geysers located at the south pole of Saturn's moon Enceladus in 2005. Later, a detailed compositional analysis of the salt-rich water ice grains in Saturn's E ring system lead to the discovery of liquid water below the crust connected to an ocean at depth feeding the icy jets. CDA was even capable to derive a spatially resolved compositional profile of the plume during close Enceladus flybys. A determination of the dust-magnetosphere interaction and the discovery of the extended E ring (at least twice as large as previously known) allowed the definition of a dynamical dust model of Saturns E ring describing the observed properties. Cassini performed shadow crossings in the ring plane and dust grain charges were measured in shadow regions delivering important data for dust-plasma interaction studies. In the last years, dedicated measurement campaigns were executed by CDA to monitor the flux of interplanetary and interstellar dust particles reaching Saturn.

Upgrade and Operation of the DNA Dust Erosion Test Facility

DTIC Science & Technology

1990-11-01

Robert G. Oeding PDA Engineering 2975 Redhill Avenue Costa Mesa, CA 92626 November 1990 ,)TICI-i -LECTE NOV 2 7,19W Techical ReportD CONTRACT No. DNA...Engineering 2975 Redhill Avenue Costa Mesa, CA 92626 PDA-TR-1385-03-01 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING

KSC-2013-3905

NASA Image and Video Library

2013-11-07

CAPE CANAVERAL, Fla. -- Dr. Carlos Calle, senior research scientist on the Electrodynamic Dust Shield for Dust Mitigation project, demonstrates a dust particle experiment in the Electrostatics and Surface Physics Laboratory in the SwampWorks at NASA's Kennedy Space Center in Florida. The technology works by creating an electric field that propagates out like the ripples on a pond. This could prevent dust accumulation on spacesuits, thermal radiators, solar panels, optical instruments and view ports for future lunar and Mars exploration activities. Electrodynamic dust shield, or EDS, technology is based on concepts originally developed by NASA as early as 1967 and later by the University of Tokyo. In 2003, NASA, in collaboration with the University of Arkansas at Little Rock, started development of the EDS for dust particle removal from solar panels to be used on future missions to the moon, an asteroid or Mars. A flight experiment to expose the dust shields to the space environment currently is under development. For more information, visit: http://www.nasa.gov/content/scientists-developing-ways-to-mitigate-dust-problem-for-explorers/ Photo credit: NASA/Dan Casper

KSC-2013-3903

NASA Image and Video Library

2013-11-07

CAPE CANAVERAL, Fla. -- Dr. Carlos Calle, senior research scientist on the Electrodynamic Dust Shield for Dust Mitigation project, demonstrates a dust particle experiment in the Electrostatics and Surface Physics Laboratory in the SwampWorks at NASA's Kennedy Space Center in Florida. The technology works by creating an electric field that propagates out like the ripples on a pond. This could prevent dust accumulation on spacesuits, thermal radiators, solar panels, optical instruments and view ports for future lunar and Mars exploration activities. Electrodynamic dust shield, or EDS, technology is based on concepts originally developed by NASA as early as 1967 and later by the University of Tokyo. In 2003, NASA, in collaboration with the University of Arkansas at Little Rock, started development of the EDS for dust particle removal from solar panels to be used on future missions to the moon, an asteroid or Mars. A flight experiment to expose the dust shields to the space environment currently is under development. For more information, visit: http://www.nasa.gov/content/scientists-developing-ways-to-mitigate-dust-problem-for-explorers/ Photo credit: NASA/Dan Casper

Near Real Time website for IASI observations of atmospheric anomalies

NASA Astrophysics Data System (ADS)

Hayer, Catherine; Grainger, Don; Marsh, Kevin; Carboni, Elisa; Ventress, Lucy; Smith, Andrew

2014-05-01

Rapid analysis of satellite observations of the state of the atmosphere and the contaminant levels within it can be used for pollution monitoring, forest fire detection and volcanic activity monitoring. There are numerous operational satellite instruments for which this is possible. The IASI instruments, currently flying on board the MetOp-A and MetOp-B satellite platforms, are used to produce Near Real Time (NRT) data using analysis algorithms developed by Oxford University. The data is then displayed on a website within 3 hours of measurement. This allows for the semi-continuous monitoring of the state of the atmosphere over most of the globe, both in daylight and at night. Global coverage is achieved 4 times per day, which is a significant advantage over most of the alternatives, either geostationary, giving limited spatial coverage, or UV instruments which are only able to observe during the daylight side of the orbit. The website includes flags for atmospheric contaminants detectable by IASI, including dust, biomass burning-derived species and volcanic ash and SO2. In the near future, the website will be developed to also include a quantitative estimate of the mass loading of SO2 contained within any volcanic cloud. Emissions of volcanic products, such as ash and SO2, are useful indicators of a change in the activity level of a volcano. Since many volcanoes are only monitored by remote sensing methods, such as satellite instruments, this can be the only such indicator available. These emissions are also dangerous to passing aircraft, causing damage to external surfaces of the plane and to the engines, sometimes leading to failure. Evacuation of regions surrounding volcanoes, and cessation or diversion of air traffic around actively erupting volcanoes is costly and highly disruptive but is sometimes required. Up to date information is of critical importance as to when to make these sensitive decisions. An archive of data will be available to allow for easy comparison with previous related events, such as large dust storms, forest fires or volcanic eruptions over the whole of the IASI lifetime. The website is being developed in conjunction with the Centre for Environmental Data Archival (CEDA).

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.

Diesel bus emissions measured in a tunnel study.

PubMed

Jamriska, Milan; Morawska, Lidia; Thomas, Steven; He, Congrong

2004-12-15

The emission factors of a bus fleet consisting of approximately 300 diesel-powered buses were measured in a tunnel study under well-controlled conditions during a 2-d monitoring campaign in Brisbane. Particle number and mass concentration levels of submicrometer particles and PM2.5 were monitored by SMPS and DustTrak instruments at the tunnel's entrance and exit, respectively. Correlation between DustTrak and TEOM response to diesel emissions was assessed, and the DustTrak results were recalculated into TEOM equivalent data. The mean value of the number and mass emission factors was (3.11+/-2.41) x 10(14) particles km(-1) for submicrometer particles and 583+/-451 mg km(-1) for PM2.5 (DustTrak), respectively. TEOM PM2.5 equivalent emission factor was 267+/-207 mg km(-1). The results are in good agreement with the emission factors determined from steady-state dynamometer testing of 12 buses from the same Brisbane City bus fleet. The results indicate that when carefully designed, both approaches, the dynamometer and on-road studies, can provide comparable results, applicable for the assessment of the effect of traffic emissions on airborne particle pollution. A brief overview of emission factors determined from other on-road and dynamometer studies reported in the literature as well as with the regulatory values used for the vehicle emission inventory assessment is presented and compared with the results obtained in this study.

STUDY ON A STEP-ADVANCED FILTER MONITOR FOR CONTINUOUS RADON PROGENY MEASUREMENT.

PubMed

Zhang, Lei; Yang, Jinmin; Guo, Qiuju

2017-04-01

Traditional fixed-filter radon progeny monitors are usually clogged with the loading of dust and cannot be used for radon progeny continuous measurement for long period. To solve this problem, a step-advanced filter (SAF) monitor for radon progeny measurement was developed. This monitor automatically roll and stop the filter at each interview. Radon progeny is collected on a 'fresh' filter at a flowrate of 3 L/min. At the same time, alpha and beta particles emitted from filter are recorded by a PIPS detector. A newly developed alpha-beta spectrum method was used for radon progeny concentration calculation. The 218Po, 214Pb and 214Bi concentrations as well as equilibrium equivalent concentration (EEC) could be worked out at the same time. The lower level limit detection of this monitor is 0.48 Bq m-3 (EEC) for 1h interval. Comparison experiments were carried out in the radon chamber at the National Institute of Metrology of China. The measurement results of this SAF monitor are consistent with EQF3220 (SARAD GmbH, Germany), and the uncertainty is smaller. Due to its high sensitivity, the periodical variation of radon progeny concentration can be easily observed by this monitor. The SAF moniter is suitable for continuous measurement in both indoor and outdoor environments. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model

NASA Astrophysics Data System (ADS)

Stovern, Michael; Felix, Omar; Csavina, Janae; Rine, Kyle P.; Russell, MacKenzie R.; Jones, Robert M.; King, Matt; Betterton, Eric A.; Sáez, A. Eduardo

2014-09-01

Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of dust and aerosol from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. Using a computational fluid dynamics model, we model dust transport from the mine tailings to the surrounding region. The model includes gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport is used to track the trajectories of larger particles and to monitor their deposition locations. In order to improve the accuracy of the dust transport simulations, both regional topographical features and local weather patterns have been incorporated into the model simulations. Results show that local topography and wind velocity profiles are the major factors that control deposition.

Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model.

PubMed

Stovern, Michael; Felix, Omar; Csavina, Janae; Rine, Kyle P; Russell, MacKenzie R; Jones, Robert M; King, Matt; Betterton, Eric A; Sáez, A Eduardo

2014-09-01

Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of dust and aerosol from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. Using a computational fluid dynamics model, we model dust transport from the mine tailings to the surrounding region. The model includes gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport is used to track the trajectories of larger particles and to monitor their deposition locations. In order to improve the accuracy of the dust transport simulations, both regional topographical features and local weather patterns have been incorporated into the model simulations. Results show that local topography and wind velocity profiles are the major factors that control deposition.

An exterior and interior leaded dust deposition survey in New York City: results of a 2-year study.

PubMed

Caravanos, Jack; Weiss, Arlene L; Jaeger, Rudolph J

2006-02-01

Environmental concentrations of leaded dust were monitored by weekly sample collection of interior and exterior settled dust that had accumulated due to atmospheric deposition. The weekly deposition amounts were measured and the cumulative rates of lead in dust that deposited on a weekly basis over 2 year's time were determined. The sampling analysis revealed that the median values of leaded dust for the interior plate (adjacent to the open window), unsheltered exterior plate, and the sheltered exterior plate were 4.8, 14.2, and 32.3 microg/feet2/week, respectively. The data supports the existence of a continuous source of deposited leaded dust in interior and exterior locations within New York City. Additional data from a control plate (interior plate with the window closed) demonstrate that the source of the interior lead deposition was from exterior (environmental) sources. Because of the ubiquitous nature of lead in our environment and the toxic threat of lead to the cognitive health of children, this data provides a framework for the understanding of environmental exposure to lead and its potential for continuing accumulation within an urban environment.

Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model

PubMed Central

Stovern, Michael; Felix, Omar; Csavina, Janae; Rine, Kyle P.; Russell, MacKenzie R.; Jones, Robert M.; King, Matt; Betterton, Eric A.; Sáez, A. Eduardo

2014-01-01

Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of dust and aerosol from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. Using a computational fluid dynamics model, we model dust transport from the mine tailings to the surrounding region. The model includes gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport is used to track the trajectories of larger particles and to monitor their deposition locations. In order to improve the accuracy of the dust transport simulations, both regional topographical features and local weather patterns have been incorporated into the model simulations. Results show that local topography and wind velocity profiles are the major factors that control deposition. PMID:25621085

A Mid-IR Census of Dusty Supernovae From the Past Decade In Preparation for JWST

NASA Astrophysics Data System (ADS)

Fox, Ori; Andrews, Jennifer; Arendt, Rick; Clayton, Geoff; Dwek, Eli; Filippenko, Alex; Johansson, Joel; Kelly, Patrick; Krafton, Kelsie; Marston, Tony; Mauerhan, Jon; Szalai, Tamas; Van Dyk, Schuyler

2018-05-01

Over the past decade, our team has shown that a surprising number of different supernova (SN) subclasses have members that exhibit mid-infrared (mid-IR) emission from warm dust at late times (>100 days post-explosion). This work has used Spitzer 3.6 and 4.5 micron imaging to constrain the dust origin and heating mechanisms, but a number of questions still remain. How much dust can SNe IIP produce in their ejecta? What progenitor can produce such extreme mass-loss events required to form the large, dense, pre-existing dust shells observed in so many cases? Many of these SNe remain bright today, in some cases more than a decade after discovery. Continued mid-IR monitoring is necessary to answer these questions by measuring the full extent of either the newly formed dust mass or pre-existing dust shell. Furthermore, Spitzer observations of both old and new SNe will provide up to date flux estimates as we prepare for continued observations with JWST. This proposal will cap off nearly a decade of work and bridge the gap to the first few cycles of JWST.

Prediction of Aerosol Optical Depth in West Asia: Machine Learning Methods versus Numerical Models

NASA Astrophysics Data System (ADS)

Omid Nabavi, Seyed; Haimberger, Leopold; Abbasi, Reyhaneh; Samimi, Cyrus

2017-04-01

Dust-prone areas of West Asia are releasing increasingly large amounts of dust particles during warm months. Because of the lack of ground-based observations in the region, this phenomenon is mainly monitored through remotely sensed aerosol products. The recent development of mesoscale Numerical Models (NMs) has offered an unprecedented opportunity to predict dust emission, and, subsequently Aerosol Optical Depth (AOD), at finer spatial and temporal resolutions. Nevertheless, the significant uncertainties in input data and simulations of dust activation and transport limit the performance of numerical models in dust prediction. The presented study aims to evaluate if machine-learning algorithms (MLAs), which require much less computational expense, can yield the same or even better performance than NMs. Deep blue (DB) AOD, which is observed by satellites but also predicted by MLAs and NMs, is used for validation. We concentrate our evaluations on the over dry Iraq plains, known as the main origin of recently intensified dust storms in West Asia. Here we examine the performance of four MLAs including Linear regression Model (LM), Support Vector Machine (SVM), Artificial Neural Network (ANN), Multivariate Adaptive Regression Splines (MARS). The Weather Research and Forecasting model coupled to Chemistry (WRF-Chem) and the Dust REgional Atmosphere Model (DREAM) are included as NMs. The MACC aerosol re-analysis of European Centre for Medium-range Weather Forecast (ECMWF) is also included, although it has assimilated satellite-based AOD data. Using the Recursive Feature Elimination (RFE) method, nine environmental features including soil moisture and temperature, NDVI, dust source function, albedo, dust uplift potential, vertical velocity, precipitation and 9-month SPEI drought index are selected for dust (AOD) modeling by MLAs. During the feature selection process, we noticed that NDVI and SPEI are of the highest importance in MLAs predictions. The data set was divided into a training (2003-2010) and a testing (2011-2013) subset. The evaluation using the two subsets shows that ANN outperformed all other MLAs and NMs. Verified to monthly mean MODIS DB AOD, ANN yielded a Spearman correlation coefficient (SCC) of 0.74, whereas SCC of 0.71 was allotted to WRF-chem simulations, as the most successful NM. In terms of simulation accuracy, SVM and MARS have yielded the lowest bias (-0.001) and RMSE (0.16). DREAM showed the poorest performance with a SCC of 0.52, a bias of -0.17 and a RMSE of 0.29.

Case study of controlled recirculation at a Wyoming trona mine

PubMed Central

Pritchard, C.; Scott, D.; Frey, G.

2015-01-01

Controlled recirculation has been used in the metal/nonmetal mining industry for energy savings when heating and cooling air, in undersea mining and for increasing airflow to mining areas. For safe and effective use of controlled district recirculation, adequate airflow to dilute contaminants must exist prior to implementation, ventilation circuit parameters must be accurately quantified, ventilation network modeling must be up to date, emergency planning scenarios must be performed and effective monitoring and control systems must be installed and used. Safety and health issues that must be considered and may be improved through the use of controlled district recirculation include blasting fumes, dust, diesel emissions, radon and contaminants from mine fires. Controlled recirculation methods are expected to become more widely used as mines reach greater working depths, requiring that these health and safety issues be well understood. The U.S. National Institute for Occupational Safety and Health (NIOSH) conducted two controlled recirculation tests over three days at a Wyoming trona mine, utilizing an inline booster fan to improve airflow to a remote and difficult-to-ventilate development section. Test results were used to determine the effect that recirculation had on air qualities and quantities measured in that section and in other adjacent areas. Pre-test conditions, including ventilation quantities and pressures, were modeled using VnetPC. During each test, ventilation quantities and pressures were measured, as well as levels of total dust. Sulfur hexafluoride (SF6) tracer gas was used to simulate a mine contaminant to monitor recirculation wave cycles. Results showed good correlation between the model results and measured values for airflows, pressure differentials, tracer gas arrival times, mine gasses and dust levels. PMID:26251567

Effects of Large-Scale Solar Installations on Dust Mobilization and Air Quality

NASA Astrophysics Data System (ADS)

Pratt, J. T.; Singh, D.; Diffenbaugh, N. S.

2012-12-01

Large-scale solar projects are increasingly being developed worldwide and many of these installations are located in arid, desert regions. To examine the effects of these projects on regional dust mobilization and air quality, we analyze aerosol product data from NASA's Multi-angle Imaging Spectroradiometer (MISR) at annual and seasonal time intervals near fifteen photovoltaic and solar thermal stations ranging from 5-200 MW (12-4,942 acres) in size. The stations are distributed over eight different countries and were chosen based on size, location and installation date; most of the installations are large-scale, took place in desert climates and were installed between 2006 and 2010. We also consider air quality measurements of particulate matter between 2.5 and 10 micrometers (PM10) from the Environmental Protection Agency (EPA) monitoring sites near and downwind from the project installations in the U.S. We use monthly wind data from the NOAA's National Center for Atmospheric Prediction (NCEP) Global Reanalysis to select the stations downwind from the installations, and then perform statistical analysis on the data to identify any significant changes in these quantities. We find that fourteen of the fifteen regions have lower aerosol product after the start of the installations as well as all six PM10 monitoring stations showing lower particulate matter measurements after construction commenced. Results fail to show any statistically significant differences in aerosol optical index or PM10 measurements before and after the large-scale solar installations. However, many of the large installations are very recent, and there is insufficient data to fully understand the long-term effects on air quality. More data and higher resolution analysis is necessary to better understand the relationship between large-scale solar, dust and air quality.

Bakery flour dust exposure causes non-allergic inflammation and enhances allergic airway inflammation in mice

PubMed Central

Marraccini, Paolo; Brass, David M.; Hollingsworth, John W.; Maruoka, Shuichiro; Garantziotis, Stavros; Schwartz, David A.

2014-01-01

Background Baker’s asthma is one of the most commonly reported occupational lung diseases in countries where fresh bread is baked daily in large quantities, and is characterized by rhinitis, bronchial hyperresponsiveness, and reversible airflow obstruction. Epidemiological studies have identified pre-existing atopy as an important risk factor for developing baker’s asthma, yet the etiology and pathogenesis of baker’s asthma remain poorly understood. Objective We sought to develop a mouse model of baker’s asthma that could be used to characterize the development and progression of baker’s asthma. Methods We were unable to sensitize mice to bakery flour dust or flour dust extract. We assessed total inflammatory cells, cellular differential, total serum IgE and the pro-inflammatory cytokine response to oropharyngeally instilled bakery flour dust or flour dust extract by itself or in the context of OVA sensitization and challenge. Results Both bakery flour dust and flour dust extract consistently elicited a neutrophilic inflammation in a tlr4-independent manner; suggesting that endotoxin is not playing a role in the inflammatory response to flour dust. Moreover, bakery flour dust and dust extract significantly enhance the inflammatory response in OVA sensitized and challenged mice. Conclusions Bakery flour dust and flour dust extract are strongly pro-inflammatory and can cause non-allergic airway inflammation and can enhance allergen-mediated airway inflammation. PMID:18564331

Dust/Regolith for Surface Exploration

NASA Technical Reports Server (NTRS)

Peters, Benjamin

2017-01-01

System-wide dust protection is a key design driver for xEMUsurface operations, and development of dust proof mechanisms, bearings, materials, and coatings coupled with specific operations and surface architecture development is critical for success.

KSC-2013-3901

NASA Image and Video Library

2013-11-07

CAPE CANAVERAL, Fla. -- Dr. Carlos Calle, senior research scientist on the Electrodynamic Dust Shield for Dust Mitigation project, demonstrates equipment used in his experiments in the Electrostatics and Surface Physics Laboratory in the SwampWorks at NASA's Kennedy Space Center in Florida. Electrodynamic dust shield, or EDS, technology is based on concepts originally developed by NASA as early as 1967 and later by the University of Tokyo. In 2003, NASA, in collaboration with the University of Arkansas at Little Rock, started development of the EDS for dust particle removal from solar panels to be used on future missions to the moon, an asteroid or Mars. A flight experiment to expose the dust shields to the space environment currently is under development. For more information, visit: http://www.nasa.gov/content/scientists-developing-ways-to-mitigate-dust-problem-for-explorers/ Photo credit: NASA/Dan Casper

Source apportionment of airborne particulate matter using organic compounds as tracers

NASA Astrophysics Data System (ADS)

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

A chemical mass balance receptor model based on organic compounds has been developed that relates source contributions to airborne fine particle mass concentrations. Source contributions to the concentrations of specific organic compounds are revealed as well. The model is applied to four air quality monitoring sites in southern California using atmospheric organic compound concentration data and source test data collected specifically for the purpose of testing this model. The contributions of up to nine primary particle source types can be separately identified in ambient samples based on this method, and approximately 85% of the organic fine aerosol is assigned to primary sources on an annual average basis. The model provides information on source contributions to fine mass concentrations, fine organic aerosol concentrations and individual organic compound concentrations. The largest primary source contributors to fine particle mass concentrations in Los Angeles are found to include diesel engine exhaust, paved road dust, gasoline-powered vehicle exhaust, plus emissions from food cooking and wood smoke, with smaller contribution from tire dust, plant fragments, natural gas combustion aerosol, and cigarette smoke. Once these primary aerosol source contributions are added to the secondary sulfates, nitrates and organics present, virtually all of the annual average fine particle mass at Los Angeles area monitoring sites can be assigned to its source.

Source apportionment of airborne particulate matter using organic compounds as tracers

NASA Astrophysics Data System (ADS)

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

A chemical mass balance receptor model based on organic compounds has been developed that relates sours; contributions to airborne fine particle mass concentrations. Source contributions to the concentrations of specific organic compounds are revealed as well. The model is applied to four air quality monitoring sites in southern California using atmospheric organic compound concentration data and source test data collected specifically for the purpose of testing this model. The contributions of up to nine primary particle source types can be separately identified in ambient samples based on this method, and approximately 85% of the organic fine aerosol is assigned to primary sources on an annual average basis. The model provides information on source contributions to fine mass concentrations, fine organic aerosol concentrations and individual organic compound concentrations. The largest primary source contributors to fine particle mass concentrations in Los Angeles are found to include diesel engine exhaust, paved road dust, gasoline-powered vehicle exhaust, plus emissions from food cooking and wood smoke, with smaller contribution:; from tire dust, plant fragments, natural gas combustion aerosol, and cigarette smoke. Once these primary aerosol source contributions are added to the secondary sulfates, nitrates and organics present, virtually all of the annual average fine particle mass at Los Angeles area monitoring sites can be assigned to its source.

The Lunar Environment: Determining the Health Effects of Exposure to Moon Dusts

NASA Technical Reports Server (NTRS)

Khan-Mayberry, Noreen

2007-01-01

The moon's surface is covered with a thin layer of fine, charged, reactive dust capable of layer of fine, charged, reactive dust capable of capable of entering habitats and vehicle compartments, where it can result in crewmember health problems. NASA formed the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) to study the effects of exposure to Lunar Dust on human health. To date, no scientifically defensible toxicological studies have been performed on lunar dusts, specifically the determination of exposure limits and their affect on human health. The multi-center LADTAG (Lunar Airborne Dust Toxicology center LADTAG (Lunar Airborne Dust Toxicology Advisory Group) was formed in response to the Office of the Chief Health and Medical Office s (OCHMO) request to develop recommendations for defining risk (OCHMO) request to develop recommendations for defining risk defining risk criteria for human lunar dust exposure.

Mineralogical, Chemical, and Optical Interrelationships of Airborne Mineral Dusts

NASA Astrophysics Data System (ADS)

Engelbrecht, J. P.; Moosmuller, H.; Pincock, S. L.; Jayanty, R. K. M.; Casuccio, G.

2014-12-01

The purpose of the project was to provide information on the mineralogical, chemical and physical interrelationships of re-suspended mineral dust samples collected as grab samples from global dust sources. Surface soil samples were collected from about 65 desert sites, including the southwestern USA (12), Mali (3), Chad (3), Morocco (1), Canary Islands (8), Cape Verde (1), Djibouti (1), Afghanistan (3), Iraq (6), Kuwait (5), Qatar (1), UAE (1), Serbia (3), China (5), Namibia (3), Botswana (4), Australia (3), and Chile (1). The < 38 μm sieved fraction of each sample was re-suspended in an entrainment chamber, from which the airborne mineral dust could be monitored, sampled and analyzed. Instruments integrated into the entrainment facility included two PM10 and two PM2.5 filter samplers, a beta attenuation gauge for the continuous measurement of PM10 and PM2.5 particulate mass fractions, an aerodynamic particle size (APS) analyzer, and a three wavelength (405, 532, 781nm) photoacoustic resonator with integrating reciprocal nephelometer for monitoring absorption and scattering coefficients during the dust re-suspension process. Filter sample media included Teflon® membrane and quartz fiber filters for chemical analysis (71 species), and Nuclepore® filters for individual particle analysis by Scanning Electron Microscopy (SEM). The < 38 μm sieved fractions were also analyzed by X-ray diffraction for their mineral content while the > 38 μm, < 125 μm soil fractions were mineralogically characterized by optical microscopy. We will be presenting results on the optical measurements, also showing the relationship between single scattering albedo (SSA) at three different wavelengths, and chemical as well as mineralogical content and interdependencies of the entrained dust samples. Examples showing the relationships between the single scattering albedos of airborne dusts, and iron (Fe) in hematite, goethite, and clay minerals (montmorillonite, illite, palygorskite), will be discussed. Differences between the clay minerals in samples from Mali and those from other localities are demonstrated. We intend establishing a data base for applications in climate modeling, remote sensing, visibility, health (medical geology), ocean fertilization, and damage to equipment.

Long-term Monitoring of Comet 103P/Hartley 2

NASA Astrophysics Data System (ADS)

Lin, Z.-Y.; Lara, L. M.; Ip, W.-H.

2013-07-01

We report the spectrophotometric, photometric, and imaging monitoring results of comet 103P/Hartley 2 obtained at the Lulin (1 m), Calar Alto (2.2 m), and Beijing Astronomical (2.16 m) observatories from 2010 April to December. We found that a dust feature in the sunward direction was detected starting from the end of September until the beginning of December (our last observation from the Lulin and Calar Alto observatories). Two distinct sunward jet features in the processed images were observed on October 11 and after October 29 until November 2. In parallel, the CN images reveal two asymmetrical jet features which are nearly perpendicular to the Sun-nucleus direction, these asymmetrical features imply that the comet was in a nearly side-on view in late October and early November. In addition to the jet features, the average result of the C2-to-CN production rate ratio ranges from 0.7 to 1.5, consistent with 103P/Hartley 2 being of typical cometary chemistry. We found that the rh dependence for the dust production rate, Afρ (5000 km), is -3.75 ± 0.45 before perihelion and -3.44 ± 1.20 during the post-perihelion period. We detected higher dust reddening around the optocenter and decreased reddening along the sunward jet feature. We concluded that higher dust reddening could be associated with strong jet activity while lower dust reddening could be associated with the outburst or might imply changes in the optical properties. The average dust color did not appear to vary significantly as the comet passed through perihelion. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC), at Lulin Observatory operated by the Institute of Astronomy, National Central University in Taiwan, and at Xinglong Station inaugurated by the National Astronomical Observatory (BAO), Beijing.

Detecting and assessing Saharan dust contribution to PM10 loads: A pilot study within the EU-Life+10 project DIAPASON

NASA Astrophysics Data System (ADS)

Gobbi, Gian Paolo; Barnaba, Francesca; Bolignano, Andrea; Costabile, Francesca; Di Liberto, Luca; Dionisi, Davide; Drewnick, Frank; Lucarelli, Franco; Manigrasso, Maurizio; Nava, Silvia; Sauvage, Laurent; Sozzi, Roberto; Struckmeier, Caroline; Wille, Holger

2015-04-01

The EC LIFE+2010 DIAPASON Project (Desert dust Impact on Air quality through model-Predictions and Advanced Sensors ObservatioNs, www.diapason-life.eu) intends to contribute new methodologies to assess the role of aerosol advections of Saharan dust to the local PM loads recorded in Europe. To this goal, automated Polarization Lidar-Ceilometers (PLCs) were prototyped within DIAPASON to certify the presence of Saharan dust plumes and support evaluating their mass loadings in the lowermost atmosphere. The whole process also involves operational dust forecasts, as well as satellite and in-situ observations. Demonstration of the Project is implemented in the pilot region of Rome (Central Italy) where three networked DIAPASON PLCs started, in October 2013 a year-round, 24h/day monitoring of the altitude-resolved aerosol backscatter and depolarization profiles. Two intensive observational periods (IOPs) involving chemical analysis and detailed physical characterization of aerosol samples have also been carried out in this year-long campaign, namely in Fall 2013 and Spring 2014. These allowed for an extensive interpretation of the PLC observations, highlighting important synergies between the PLC and the in situ data. The presentation will address capabilities of the employed PLCs, observations agreement with model forecasts of dust advections, retrievals of aerosol properties and methodologies developed to detect Saharan advections and to evaluate the relevant mass contribution to PM10. This latter task is intended to provide suggestions on possible improvements to the current EC Guidelines (2011) on this matter. In fact, specific Guidelines are delivered by the European Commission to provide the Member States a common method to asses the Saharan dust contribution to the currently legislated PM-related Air Quality metrics. The DIAPASON experience shows that improvements can be proposed to make the current EC Methodology more robust and flexible. The methodology DIAPASON recommends has been designed and validated taking advantage of the PLC observations and highlights the benefits of the operational use of such systems in routine Air Quality applications. Concurrently, PLC activities are contributing to the COST Action "TOPROF", an European effort aiming at the setup and operational use of Lidar-Ceilometers networks for meteorological and safety purposes.

Can dust emission mechanisms be determined from field measurements?

USDA-ARS?s Scientific Manuscript database

Field observations are needed to develop and test theories on dust emission for use in dust modeling systems. The dust emission mechanism (aerodynamic entrainment, saltation bombardment, aggregate disintegration) as well as the amount and particle-size distribution of emitted dust may vary under sed...

Development of High-Resolution Dynamic Dust Source Function - A Case Study with a Strong Dust Storm in a Regional Model

NASA Technical Reports Server (NTRS)

Kim, Dongchul; Chin, Mian; Kemp, Eric M.; Tao, Zhining; Peters-Lidard, Christa D.; Ginoux, Paul

2017-01-01

A high-resolution dynamic dust source has been developed in the NASA Unified-Weather Research and Forecasting (NU-WRF) model to improve the existing coarse static dust source. In the new dust source map, topographic depression is in 1-km resolution and surface bareness is derived using the Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS). The new dust source better resolves the complex topographic distribution over the Western United States where its magnitude is higher than the existing, coarser resolution static source. A case study is conducted with an extreme dust storm that occurred in Phoenix, Arizona in 0203 UTC July 6, 2011. The NU-WRF model with the new high-resolution dynamic dust source is able to successfully capture the dust storm, which was not achieved with the old source identification. However the case study also reveals several challenges in reproducing the time evolution of the short-lived, extreme dust storm events.

Development of High-Resolution Dynamic Dust Source Function -A Case Study with a Strong Dust Storm in a Regional Model

PubMed Central

Kim, Dongchul; Chin, Mian; Kemp, Eric M.; Tao, Zhining; Peters-Lidard, Christa D.; Ginoux, Paul

2018-01-01

A high-resolution dynamic dust source has been developed in the NASA Unified-Weather Research and Forecasting (NU-WRF) model to improve the existing coarse static dust source. In the new dust source map, topographic depression is in 1-km resolution and surface bareness is derived using the Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS). The new dust source better resolves the complex topographic distribution over the Western United States where its magnitude is higher than the existing, coarser resolution static source. A case study is conducted with an extreme dust storm that occurred in Phoenix, Arizona in 02-03 UTC July 6, 2011. The NU-WRF model with the new high-resolution dynamic dust source is able to successfully capture the dust storm, which was not achieved with the old source identification. However the case study also reveals several challenges in reproducing the time evolution of the short-lived, extreme dust storm events. PMID:29632432

Development of High-Resolution Dynamic Dust Source Function -A Case Study with a Strong Dust Storm in a Regional Model.

PubMed

Kim, Dongchul; Chin, Mian; Kemp, Eric M; Tao, Zhining; Peters-Lidard, Christa D; Ginoux, Paul

2017-06-01

A high-resolution dynamic dust source has been developed in the NASA Unified-Weather Research and Forecasting (NU-WRF) model to improve the existing coarse static dust source. In the new dust source map, topographic depression is in 1-km resolution and surface bareness is derived using the Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS). The new dust source better resolves the complex topographic distribution over the Western United States where its magnitude is higher than the existing, coarser resolution static source. A case study is conducted with an extreme dust storm that occurred in Phoenix, Arizona in 02-03 UTC July 6, 2011. The NU-WRF model with the new high-resolution dynamic dust source is able to successfully capture the dust storm, which was not achieved with the old source identification. However the case study also reveals several challenges in reproducing the time evolution of the short-lived, extreme dust storm events.

[Influence of traffic restriction on road and construction fugitive dust].

PubMed

Tian, Gang; Li, Gang; Qin, Jian-Ping; Fan, Shou-Bin; Huang, Yu-Hu; Nie, Lei

2009-05-15

By monitoring the road and construction dust fall continuously during the "Good Luck Beijing" sport events, the reduction of road and construction dust fall caused by traffic restriction was studied. The contribution rate of road and construction dust to particulate matter of Beijing atmosphere environment, and the emission ratio of it to total local PM10 emission were analyzed. The results show that the traffic restriction reduces road and construction dust fall significantly. The dust fall average value of ring roads was 0.27 g x (m2 x d)(-1) in the "traffic restriction" period, and the values were 0.81 and 0.59 g x (m2 x d)(-1) 1 month and 7 days before. The dust fall average value of major arterial and minor arterial was 0.21 g x (m2 x d)(-1) in the "traffic restriction" period, and the values were 0.54 and 0.58 g x (m2 x d)(-1) 1 month and 7 days before. The roads emission reduced 60%-70% compared with before traffic restriction. The dust fall average values of civil architecture and utility architecture were 0.61 and 1.06 g x (m2 x d)(-1) in the "traffic restriction" period, and the values were 1.15 and 1.55 g x (m2 x d)(-1) 20 days before. The construction dust reduced 30%-47% compared with 20 days before traffic restriction. Road and construction dust emission are the main source of atmosphere particulate matter in Beijing, and its contribution to ambient PM10 concentration is 21%-36%. PM10 emitted from roads and constructions account for 42%-72% and 30%-51% of local emission while the local PM10 account for 50% and 70% of the total emission.

Space Shuttle Environmental Effects: The First 5 Flights

NASA Technical Reports Server (NTRS)

Potter, A. (Editor)

1983-01-01

Environmental effects associated with the first five Space Shuttle flights were monitored by the National Aeronautics and Space Administration (NASA) and the U.S. Air Force (USAF). Results and interpretations from this effort were reported at the December 1982 joint NASA-USAF conference. The conference proceedings are presented in this document. Most of the monitoring activity was focused on the launch cloud, emphasizing surface effects on the biota and air quality, model prediction of surface concentrations of HCl gas and Al2O3 dust, and airborne measurements of cloud composition. In general, assessments and predictions made in the April 1978 Final Environmental Impact Statement for the Space Shuttle Program were verified. Fallout of acidic mist and dust within 3 mi to 5 mi of the launch pad was the only unexpected effect of the launch. Atomization of deluge water in the Shuttle exhaust is considered to be the most probable cause of this effect. Sonic booms were monitored for several landings at Edwards Air Force Base, California; results agreed well with model predictions.

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.

Temporal and Spatial Variations in Fine and Coarse Particles in Seoul, Korea

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

Ghim, Young Sung

2015-01-01

Concentrations of fine (PM2.5) and coarse particles (PM10 -2.5), whose diameters are less 2.5 µm, and between 2.5 and 10 µm, respectively, at ambient air monitoring stations in Seoul between 2002 and 2008 were analyzed. Effects of Asian dust are mainly manifested as concentration spikes of PM10 - 2.5 but were considerable on PM2.5 levels in 2002 when Asian dust storms were the strongest. Excluding the effects of Asian dust, annual average PM2.5 showed a downward trend. Despite a similarity in year - to - year variations, PM10- 2.5, mostly affected by fugitive dust emissions, and CO and NO2, primarilymore » affected by motor vehicle emissions, did not show a decrease. PM2.5 along with CO and NO2 had the highest values during the morning rush hour. PM10 - 2.5 peak lagged about one hour behind that of PM2.5 because of fugitive dust emissions despite an increasing mixing height. On high PM2.5 days, PM2. 5 peaks occurred two hours later than usual as the effects of secondary formation became more important. A test for the spatial variabilities shows that PM10 - 2.5, which is known to be greatly influenced by local effects, is lower in its correlation coeffic ient and higher in its coefficient of divergence (COD, which serves as an indicator for spatial variability) than PM2.5, albeit that the difference between the two is small. The average COD of PM2.5 among monitoring stations was about 0.2 but was lowered t o 0.13 when considering high PM2.5 days only, which signifies that spatial uniformity increases significantly.« less

Health effects of World Trade Center (WTC) Dust: An unprecedented disaster with inadequate risk management

PubMed Central

Lippmann, Morton; Cohen, Mitchell D.; Chen, Lung-Chi

2015-01-01

The World Trade Center (WTC) twin towers in New York City collapsed on 9/11/2001, converting much of the buildings’ huge masses into dense dust clouds of particles that settled on the streets and within buildings throughout Lower Manhattan. About 80–90% of the settled WTC Dust, ranging in particle size from ~2.5 μm upward, was a highly alkaline mixture of crushed concrete, gypsum, and synthetic vitreous fibers (SVFs) that was readily resuspendable by physical disturbance and low-velocity air currents. High concentrations of coarse and supercoarse WTC Dust were inhaled and deposited in the conductive airways in the head and lungs, and subsequently swallowed, causing both physical and chemical irritation to the respiratory and gastroesophageal epithelia. There were both acute and chronic adverse health effects in rescue/recovery workers; cleanup workers; residents; and office workers, especially in those lacking effective personal respiratory protective equipment. The numerous health effects in these people were not those associated with the monitored PM2.5 toxicants, which were present at low concentrations, that is, asbestos fibers, transition and heavy metals, polyaromatic hydrocarbons or PAHs, and dioxins. Attention was never directed at the very high concentrations of the larger-sized and highly alkaline WTC Dust particles that, in retrospect, contained the more likely causal toxicants. Unfortunately, the initial focus of the air quality monitoring and guidance on exposure prevention programs on low-concentration components was never revised. Public agencies need to be better prepared to provide reliable guidance to the public on more appropriate means of exposure assessment, risk assessment, and preventive measures. PMID:26058443

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.

Electron Beam Analysis of Micrometeoroids Captured in Aerogel as Stardust Analogues

NASA Technical Reports Server (NTRS)

Graham, G. A.; Sheffield-Parker, J.; Bradley, P.; Kearsley, A. T.; Dai, Z. R.; Mayo, S. C.; Teslich, N.; Snead, C.; Westphal, A. J.; Ishii, H.

2005-01-01

In January 2004, NASA s Stardust spacecraft passed through the tail of Comet 81P/Wild-2. The on-board dust flux monitor instrument indicated that numerous micro- and nano-meter sized cometary dust particles were captured by the dedicated silica aerogel capture cell. The collected cometary particles will be returned to Earth in January 2006. Current Stardust analogues are: (i) Light-gas-gun accelerated individual mineral grains and carbonaceous meteoritic material in aerogels at the Stardust encounter velocity ca.approximately 6 kilometers per second. (ii) Aerogels exposed in low-Earth orbit (LEO) containing preserved cosmic dust grains. Studies of these impacts offer insight into the potential state of the captured cometary dust by Stardust and the suitability of various analytical techniques. A number of papers have discussed the application of sophisticated synchrotron analytical techniques to analyze Stardust particles. Yet much of the understanding gained on the composition and mineralogy of interplanetary dust particles (IDPs) has come from electron microscopy studies. Here we discuss the application of scanning electron microscopy (SEM) for Stardust during the preliminary phase of post-return investigations.

THE DUST ENVIRONMENT OF MAIN-BELT COMET P/2012 T1 (PANSTARRS)

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

Moreno, F.; Pozuelos, F.; Cabrera-Lavers, A.

2013-06-20

The Main-Belt Comet P/2012 T1 (PANSTARRS) has been imaged using the 10.4 m Gran Telescopio Canarias and the 4.2 m William Herschel Telescope at six epochs in the period from 2012 November to 2013 February, with the aim of monitoring its dust environment. The dust tails' brightness and morphology are best interpreted in terms of a model of sustained dust emission spanning four to six months. The total dust mass ejected is estimated at {approx}6-25 Multiplication-Sign 10{sup 6} kg. We assume a time-independent power-law size distribution function, with particles in the micrometer to centimeter size range. Based on the qualitymore » of the fits to the isophote fields, an anisotropic emission pattern is favored against an isotropic one, in which the particle ejection is concentrated toward high latitudes ({+-}45 Degree-Sign to {+-}90 Degree-Sign ) in a high-obliquity object (I = 80 Degree-Sign ). This seasonally driven ejection behavior, along with the modeled particle ejection velocities, are in remarkable agreement to those we found for P/2010 R2 (La Sagra).« less

Slope stability radar for monitoring mine walls

NASA Astrophysics Data System (ADS)

Reeves, Bryan; Noon, David A.; Stickley, Glen F.; Longstaff, Dennis

2001-11-01

Determining slope stability in a mining operation is an important task. This is especially true when the mine workings are close to a potentially unstable slope. A common technique to determine slope stability is to monitor the small precursory movements, which occur prior to collapse. The slope stability radar has been developed to remotely scan a rock slope to continuously monitor the spatial deformation of the face. Using differential radar interferometry, the system can detect deformation movements of a rough wall with sub-millimeter accuracy, and with high spatial and temporal resolution. The effects of atmospheric variations and spurious signals can be reduced via signal processing means. The advantage of radar over other monitoring techniques is that it provides full area coverage without the need for mounted reflectors or equipment on the wall. In addition, the radar waves adequately penetrate through rain, dust and smoke to give reliable measurements, twenty-four hours a day. The system has been trialed at three open-cut coal mines in Australia, which demonstrated the potential for real-time monitoring of slope stability during active mining operations.

Dust storm in Alaska

NASA Image and Video Library

2013-11-18

Dust storm in Alaska captured by Aqua/MODIS on Nov. 17, 2013 at 21:45 UTC. When glaciers grind against underlying bedrock, they produce a silty powder with grains finer than sand. Geologists call it “glacial flour” or “rock flour.” This iron- and feldspar-rich substance often finds its ways into rivers and lakes, coloring the water brown, grey, or aqua. When river or lake levels are low, the flour accumulates on drying riverbanks and deltas, leaving raw material for winds to lift into the air and create plumes of dust. Scientists are monitoring Arctic dust for a number of reasons. Dust storms can reduce visibility enough to disrupt air travel, and they can pose health hazards to people on the ground. Dust is also a key source of iron for phytoplankton in regional waters. Finally, there is the possibility that dust events are becoming more frequent and severe due to ongoing recession of glaciers in coastal Alaska. To read more about dust storm in this region go to: earthobservatory.nasa.gov/IOTD/view.php?id=79518 Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Simulation and analysis of synoptic scale dust storms over the Arabian Peninsula

NASA Astrophysics Data System (ADS)

Beegum, S. Naseema; Gherboudj, Imen; Chaouch, Naira; Temimi, Marouane; Ghedira, Hosni

2018-01-01

Dust storms are among the most severe environmental problems in arid and semi-arid regions of the world. The predictability of seven dust events, viz. D1: April 2-4, 2014; D2: February 23-24, 2015; D3: April 1-3, 2015; D4: March 26-28, 2016; D5: August 3-5, 2016; D6: March 13-14, 2017 and D7:March 19-21, 2017, are investigated over the Arabian Peninsula using a regionally adapted chemistry transport model CHIMERE coupled with the Weather Research and Forecast (WRF) model. The hourly forecast products of particulate matter concentrations (PM10) and aerosol optical depths (AOD) are compared against both satellite-based (MSG/SEVRI RGB dust, MODIS Deep Blue Aerosol Optical Depth: DB-AOD, Ozone Monitoring Instrument observed UV Aerosol Absorption Index: OMI-AI) and ground-based (AERONET AOD) remote sensing products. The spatial pattern and the time series of the simulations show good agreement with the observations in terms of the dust intensity as well as the spatiotemporal distribution. The causative mechanisms of these dust events are identified by the concurrent analyses of the meteorological data. From these seven storms, five are associated with synoptic scale meteorological processes, such as prefrontal storms (D1 and D7), postfrontal storms of short (D2), and long (D3) duration types, and a summer shamal storm (D6). However, the storms D4 and D6 are partly associated with mesoscale convective type dust episodes known as haboobs. The socio-economic impacts of the dust events have been assessed by estimating the horizontal visibility, air quality index (AQI), and the dust deposition flux (DDF) from the forecasted dust concentrations. During the extreme dust events, the horizontal visibility drops to near-zero values co-occurred withhazardous levels of AQI and extremely high dust deposition flux (250 μg cm- 2 day- 1).

10 years of Cassini/VIMS observations at Titan

NASA Astrophysics Data System (ADS)

Sotin, C.; Brown, R. H.; Baines, K. H.; Barnes, J.; Buratti, B. J.; Clark, R. N.; Jaumann, R.; LeMouelic, S.; Nicholson, P. D.; Rodriguez, S.; Soderblom, J.; Soderblom, L.; Stephan, K.

2014-04-01

The interplanetary space probe Cassini/Huygens reached Saturn in July 2004 after seven years of cruise phase. Today, the German-lead Cosmic Dust Analyser (CDA) is operated continuously for 10 years in orbit around Saturn. During the cruise phase CDA measured the interstellar dust flux at one AU distance from the Sun, the charge and composition of interplanetary dust grains and the composition of the Jovian nanodust streams. The first discovery of CDA related to Saturn was the measurement of nanometer sized dust particles ejected by its magnetosphere to interplanetary space with speeds higher than 100 km/s. Their origin and composition was analysed and an their dynamical studies showed a strong link to the conditions of the solar wind plasma flow. A recent surprising result was, that stream particles stem from the interior of Enceladus. Since 2004 CDA measured millions of dust impacts characterizing the dust environment of Saturn. The instrument showed strong evidence for ice geysers located at the south pole of Saturn's moon Enceladus in 2005. Later, a detailed compositional analysis of the salt-rich water ice grains in Saturn's E ring system lead to the discovery of liquid water below the icy crust connected to an ocean at depth feeding the icy jets. CDA was even capable to derive a spatially resolved compositional profile of the plume during close Enceladus flybys. A determination of the dust-magnetosphere interaction and the discovery of the extended E ring allowed the definition of a dynamical dust model of Saturn's E ring describing the observed properties. The measured dust density profiles in the dense E ring revealed geometric asymmetries. Cassini performed shadow crossings in the ring plane and dust grain charges were measured in shadow regions delivering important data for dust-plasma interaction studies. In the last years, dedicated measurement campaigns were executed by CDA to monitor the flux of interplanetary and interstellar dust particles reaching Saturn. Currently, the composition of interstellar grains and the meteoroid flux into the Saturnian system are in analysis.

Dust deposition and ambient PM10 concentration in northwest China: spatial and temporal variability

NASA Astrophysics Data System (ADS)

Zhang, Xiao-Xiao; Sharratt, Brenton; Chen, Xi; Wang, Zi-Fa; Liu, Lian-You; Guo, Yu-Hong; Li, Jie; Chen, Huan-Sheng; Yang, Wen-Yi

2017-02-01

Eolian dust transport and deposition are important geophysical processes which influence global bio-geochemical cycles. Currently, reliable deposition data are scarce in central and east Asia. Located at the boundary of central and east Asia, Xinjiang Province of northwestern China has long played a strategic role in cultural and economic trade between Asia and Europe. In this paper, we investigated the spatial distribution and temporal variation in dust deposition and ambient PM10 (particulate matter in aerodynamic diameter ≤ 10 µm) concentration from 2000 to 2013 in Xinjiang Province. This variation was assessed using environmental monitoring records from 14 stations in the province. Over the 14 years, annual average dust deposition across stations in the province ranged from 255.7 to 421.4 t km-2. Annual dust deposition was greater in southern Xinjiang (663.6 t km-2) than northern (147.8 t km-2) and eastern Xinjiang (194.9 t km-2). Annual average PM10 concentration across stations in the province varied from 100 to 196 µg m-3 and was 70, 115 and 239 µg m-3 in northern, eastern and southern Xinjiang, respectively. The highest annual dust deposition (1394.1 t km-2) and ambient PM10 concentration (352 µg m-3) were observed in Hotan, which is located in southern Xinjiang and at the southern boundary of the Taklamakan Desert. Dust deposition was more intense during the spring and summer than other seasons. PM10 was the main air pollutant that significantly influenced regional air quality. Annual average dust deposition increased logarithmically with ambient PM10 concentration (R2 ≥ 0.81). While the annual average dust storm frequency remained unchanged from 2000 to 2013, there was a positive relationship between dust storm days and dust deposition and PM10 concentration across stations. This study suggests that sand storms are a major factor affecting the temporal variability and spatial distribution of dust deposition in northwest China.

Dust in Rain During Drought: An Overlooked Pathway for Elemental Flux to Ecosystems

NASA Astrophysics Data System (ADS)

Ponette-González, A.; Collins, J. D., Jr.; Manuel, J. E.; Byers, T. A.; Glass, G. A.; Weathers, K. C.; Gill, T. E.

2017-12-01

Airborne dust has the potential to alter ecosystem productivity and biogeochemical cycles at local to global scales by enhancing atmospheric deposition of critical limiting nutrients and toxic pollutants. Suspended dust particles are delivered to ecosystems directly via dry deposition or in precipitation (wet deposition) by rainout and washout. Compared to dry deposition, dust removal by precipitation (dust-in-rain) is a seldom quantified yet potentially significant flux between the atmosphere and ecosystems. We quantified dust effects on the ionic and elemental composition of precipitation and on wet deposition rates at a National Atmospheric Deposition Program (NADP) monitoring site in west Texas during the extreme 2012 drought. Dust events were identified using meteorological data for stations within a 150-km radius buffer surrounding the NADP site. Data on the dissolved chemistry of weekly wet deposition samples and elemental analysis of the particulate fraction were analyzed. Calcium was the dominant dissolved ion in rainwater, comprising 61% of the total measured solute content during dust-in rain weeks. In the particulate fraction, Fe alone made up 81% of the elemental composition during dust-in-rain weeks. At this site, five dust-in-rain weeks delivered 19% of the annual water input (51 mm water). However, these weeks contributed 46-70% of the annual dissolved Ca2+, Mg2+, K+, Na+, PO43-, and Cl- flux and >55% of the particulate Fe, Ti, V, Ni, Rb, Ga, and Br flux. Sourcing analysis, conducted using an End-Member Mixing Algorithm (EMMA) on the particulate fraction identified Fe, Cu, Rb, and Sr end-members, representing 87% of the total elemental variance. In addition, EMMA showed that dust-in-rain weeks were more well mixed than other rainfall weeks. Preliminary findings for this west Texas site show that infrequent dust-in-rain events constitute an important but overlooked proportion of the elemental flux to ecosystems during severe drought.

Combustibility determination for cotton gin dust and almond huller dust

USDA-ARS?s Scientific Manuscript database

It has been documented that some dusts generated while processing agricultural products, such as grain and sugar (OSHA, 2009), can constitute combustible dust hazards. After a catastrophic dust explosion in a sugar refinery in 2008, OSHA initiated action to develop a mandatory standard to comprehen...

Size distribution of PM at Cape Verde - Santiago Island

NASA Astrophysics Data System (ADS)

Pio, C.; Nunes, T.; Cardoso, J.; Caseiro, A.; Cerqueira, M.; Custodio, D.; Freitas, M. C.; Almeida, S. M.

2012-04-01

The archipelago of Cape Verde is located on the eastern North Atlantic, about 500 km west of the African coast. Its geographical location, inside the main area of dust transport over tropical Atlantic and near the coast of Africa, is strongly affected by mineral dust from the Sahara and the Sahel regions. In the scope of the CVDust project a surface field station was implemented in the surroundings of Praia City, Santiago Island (14° 55' N e 23° 29' W, 98 m at sea level), where aerosol sampling throughout different samplers was performed during one year. To study the size distribution of aerosol, an optical dust monitor (Grimm 180), from 0.250 to 32 μm in 31 size channels, was running almost continuously from January 2011 to December 2011. The performance of Grimm 180 to quantify PM mass concentration in an area affected by the transport of Saharan dust particles was evaluated throughout the sampling period by comparison with PM10 mass concentrations obtained with the gravimetric reference method (PM10 TSI High-Volume, PM10 Partisol and PM10 TCR-Tecora). PM10 mass concentration estimated with the Grimm 180 dust monitor, an optical counter, showed a good correlation with the reference gravimetric method, with R2= 0.94 and a linear regression equation of PM10Grimm = 0.81PM10TCR- 5.34. The number and mass size distribution of PM at ground level together with meteorological and back trajectories were analyzed and compared for different conditions aiming at identifying different signatures related to sources and dust transport. January and February, the months when most Saharan dust events occurred, showed the highest concentrations, with PM10 daily average of 66.6±60.2 μg m-3 and 91.6±97.4 μg m-3, respectively. During these months PM1 and PM2.5 accounted for less than 11% and 47% of PM10 respectively, and the contribution of fine fractions (PM1 and PM2.5) to PM mass concentrations tended to increase for the other months. During Saharan dust events, the PM2.5 hourly average could reach mass concentrations higher than 200 μg m-3 whereas PM10 overpass 600 μg m-3. Acknowledgement: This work was funded by the Portuguese Science Foundation (FCT) through the project PTDD/AAC-CLI/100331/2008 and FCOMP-01-0124-FEDER-008646 (CV-Dust). J. Cardoso acknowledges the PhD grant SFRH-BD-6105-2009 from FCT.

The Martian Dust Devil Electron Avalanche: Laboratory Measurements of the E-Field Fortifying Effects of Dust-Electron Absorption

NASA Technical Reports Server (NTRS)

Farrell, W. M.; McLain, J. L.; Collier, M. R.; Keller, J. W.

2017-01-01

Analogous to terrestrial dust devils, charged dust in Mars dust devils should become vertically stratified in the convective features, creating large scale E-fields. This E-field in a Martian-like atmosphere has been shown to stimulate the development of a Townsend discharge (electron avalanche) that acts to dissipate charge in regions where charge build-up occurs. While the stratification of the charged dust is a source of the electrical energy, the uncharged particulates in the dust population may absorb a portion of these avalanching electrons, thereby inhibiting dissipation and leading to the development of anomalously large E-field values. We performed a laboratory study that does indeed show the presence of enhanced E-field strengths between an anode and cathode when dust-absorbing filaments (acting as particulates) are placed in the avalanching electron flow. Further, the E-field threshold condition to create an impulsive spark discharge increases to larger values as more filaments are placed between the anode and cathode. We conclude that the spatially separated charged dust creates the charge centers and E-fields in a dust devil, but the under-charged portion of the population acts to reduce Townsend electron dissipation currents, further fortifying the development of larger-than-expected E-fields.

Observation of a Dust Storm during 2015 Spring over Beijing, China

NASA Astrophysics Data System (ADS)

Lv, Y.; Li, D.; Li, Z.; Chen, X.; Xu, H.; Liu, Z.; Qie, L.; Zhang, Y.; Li, K.; Ma, Y.

2015-12-01

Dust events bring significant impacts on the regional environment, human health and even climate. There are four major dust explosion areas in the world, such as North America, Australia, Central Asia and Middle East. Located in the Central Asia, North China has a severe desertification because of deforestation and excessive population growth. Beijing is at the fork of three dust transmission paths in Chin, which makes it a dust-prone region for a long history especially in spring. Thanks to the improvement of the ecological environment in Mongolia, the number of dust weather in recent years reduced significantly than before. However, as the spring coming earlier for the relatively high temperature, a severe dust weather process happened suddenly on March 28, 2015 following with the long-term hazy weather, which up to the highest intensity in the nearly two years. A set of ground-based observations for this serious dust event were adopted in this paper. The ground-based remote sensing station is equipped with an automatic CIMEL lidar and an AERONET sun-photometer. Aerosol optical depth (AOD) and aerosol size distribution were measured by sun-photometer. AOD of dust reached 2.0 at 532nm, which was much larger than clear days. And there was an obvious trend that coarse mode increases more significantly and quickly than fine mode when a dust storm occurs. At the same time, data provided by the air quality monitoring and analysis platform of China shown that the PM10 concentration was larger than 1000μg/m3 and PM10 made important contribution to the high AQI. Lidar observation clearly shown the dust spread very tall (higher than 1km) when the dust storm occurrence. After the dust dissipating, the planetary boundary layer roughly from 0 to 3km, aerosol has a very widely vertical distribution. The AOD based on sun-photometer were taken as a constraint, 65 sr were retrieved and analyzed. And the extinction coefficients indicated that the dust had been dissipation near the ground, while some dissolved into the upper air (2-3km) after the dust passed over. Backward trajectory analysis showed those dust was originating from Mongolia (northwest of Beijing). According to the air quality index data, the dust transmission path could be Beijing-Tianjin-Hebei-Shandong-Jiangsu. And then it deposited at Taizhou in Jiangsu province.

Biomagnetic monitoring of heavy metals contamination in deposited atmospheric dust, a case study from Isfahan, Iran.

PubMed

Norouzi, Samira; Khademi, Hossein; Cano, Angel Faz; Acosta, Jose A

2016-05-15

Tree leaves are considered as one of the best biogenic dust collectors due to their ability to trap and retain particulate matter on their surfaces. In this study, the magnetic susceptibility (MS) and the concentration of selected heavy metals of plane tree (Platanus orientalis L.) leaves and deposited atmospheric dust, sampled by an indirect and a direct method, respectively, were determined to investigate the relationships between leaf magnetic parameters and the concentration of heavy metals in deposited atmospheric dust. The objective was to develop a biomagnetic method as an alternative to the common ones used for determining atmospheric heavy metal contaminations. Plane tree leaves were monthly sampled on the 19th of May to November, 2012 (T1-T7), for seven months from 21 different sites in the city of Isfahan, central Iran. Deposited atmospheric dust samples were also collected using flat glass surfaces from the same sites on the same dates, except for T1. MS (χlf, χhf) values in washed (WL) and unwashed leaves (UL) as well as Cu, Fe, Mn, Ni, Pb, and Zn concentrations in UL and deposited atmospheric dust samples were determined. The results showed that the MS content with a biogenic source was low with almost no significant change during the sampling period, while an increasing trend was observed in the MS content of UL samples due to the deposition of heavy metals and magnetic particles on leaf surfaces throughout the plant growth. The latter type of MS content could be reduced through washing off by rain. Most heavy metals examined, as well as the Tomlinson pollution load index (PLI) in UL, showed statistically significant correlations with MS values. The correlation between heavy metals content in atmospheric dust deposited on glass surfaces and leaf MS values was significant for Cu, Fe, Pb, and Zn. Moreover, the similarity observed between the spatial distribution maps of leaf MS and deposited atmospheric dust PLI provided convincing evidence regarding the suitability of the biomagnetic approach as a relatively rapid and inexpensive method for identifying highly polluted urban areas with selected heavy metals, especially those subjected to anthropogenic and other traffic related sources. Copyright © 2016 Elsevier Ltd. All rights reserved.

19th century London dust-yards: a case study in closed-loop resource efficiency.

PubMed

Velis, Costas A; Wilson, David C; Cheeseman, Christopher R

2009-04-01

The material recovery methods used by dust-yards in early 19th century London, England and the conditions that led to their development, success and decline are reported. The overall system developed in response to the market value of constituents of municipal waste, and particularly the high coal ash content of household 'dust'. The emergence of lucrative markets for 'soil' and 'breeze' products encouraged dust-contractors to recover effectively 100% of the residual wastes remaining after readily saleable items and materials had been removed by the thriving informal sector. Contracting dust collection to the private sector allowed parishes to keep the streets relatively clean, without the need to develop institutional capacity, and for a period this also generated useful income. The dust-yard system is, therefore, an early example of organised, municipal-wide solid waste management, and also of public-private sector participation. The dust-yard system had been working successfully for more than 50 years before the Public Health Acts of 1848 and 1875, and was thus important in facilitating a relatively smooth transition to an institutionalised, municipally-run solid waste management system in England. The dust-yards can be seen as early precursors of modern materials recycling facilities (MRFs) and mechanical-biological treatment (MBT) plants; however, it must be emphasised that dust-yards operated without any of the environmental and occupational health considerations that are indispensable today. In addition, there are analogies between dust-yards and informal sector recycling systems currently operating in many developing countries.

Increasing aeolian dust deposition to snowpacks in the Rocky Mountains inferred from snowpack, wet deposition, and aerosol chemistry

USGS Publications Warehouse

Clow, David W.; Williams, Mark W.; Schuster, Paul F.

2016-01-01

Mountain snowpacks are a vital natural resource for ∼1.5 billion people in the northern Hemisphere, helping to meet human and ecological demand for water in excess of that provided by summer rain. Springtime warming and aeolian dust deposition accelerate snowmelt, increasing the risk of water shortages during late summer, when demand is greatest. While climate networks provide data that can be used to evaluate the effect of warming on snowpack resources, there are no established regional networks for monitoring aeolian dust deposition to snow. In this study, we test the hypothesis that chemistry of snow, wet deposition, and aerosols can be used as a surrogate for dust deposition to snow. We then analyze spatial patterns and temporal trends in inferred springtime dust deposition to snow across the Rocky Mountains, USA, for 1993–2014. Geochemical evidence, including strong correlations (r2 ≥ 0.94) between Ca2+, alkalinity, and dust concentrations in snow deposited during dust events, indicate that carbonate minerals in dust impart a strong chemical signature that can be used to track dust deposition to snow. Spatial patterns in chemistry of snow, wet deposition, and aerosols indicate that dust deposition increases from north to south in the Rocky Mountains, and temporal trends indicate that winter/spring dust deposition increased by 81% in the southern Rockies during 1993–2014. Using a multivariate modeling approach, we determined that increases in dust deposition and decreases in springtime snowfall combined to accelerate snowmelt timing in the southern Rockies by approximately 7–18 days between 1993 and 2014. Previous studies have shown that aeolian dust emissions may have doubled globally during the 20th century, possibly due to drought and land-use change. Climate projections for increased aridity in the southwestern U.S., northern Africa, and other mid-latitude regions of the northern Hemisphere suggest that aeolian dust emissions may continue to increase, compounding the risk that climate warming poses to snowpack water resources in arid/semi-arid regions of the world.

Biogeochemical Impact of Long-Range Transported Dust over Northern South China Sea

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee; Wang, S. H.; Hsu, N. C.

2011-01-01

Transpacific transport and impact of Asian dust aerosols have been well documented (e.g., results from ACE-Asia and regional follow-on campaigns), but little is known about dust invasion to the South China Sea (SCS). On 19-21 March 2010, a fierce Asian dust storm affected large areas from the Gobi deserts to the West Pacific, including Taiwan and Hong Kong. As a pilot study of the 7-SEAS (Seven South East Asian Studies) in the northern SCS, detailed characteristics of long-range transported dust aerosols were first observed by a comprehensive set of ground-based instruments deployed at the Dongsha islands (20deg42'52" N, 116deg43'51" E). Aerosol measurements such as particle mass concentrations, size distribution, optical properties, hygroscopicity, and vertical profiles help illustrate the evolution of this dust outbreak. Our results indicate that these dust particles were mixed with anthropogenic and marine aerosols, and transported near the surface. Satellite assessment of biogeochemical impact of dust deposition into open oceans is hindered by our current inability in retrieving areal dust properties and ocean colors over an extensive period of time, particularly under the influence of cloudy conditions. In this paper, we analyze the changes of retrieved Chlorophyll-a (Chl-a) concentration over the northern SCS, considered as oligotophic waters in the spring, from long-term SeaWiFS measurements since 1997. Over the past decade, six long-range transported dust events are identified based on spatiotemporal evolutions of PM10 measurements from regional monitoring stations, with the aid of trajectory analysis. Multi-year composites of Chl-a imagery for dust event and non-dust background during March-April are applied to overcome insufficient retrievals of Chl-a due to cloudy environment. Due to anthropogenic modification within a shallow boundary layer off the densely populated and industrial southeast coast of China, the iron ion activation of deliquescent dust particles enhances the efficiency of fertilization for biological productivity. Compared to the West Pacific, the marine ecosystem in the northern SCS is much more susceptible to the biogeochemical impact of long-range transported Asian dust.

Using operational active remote sensing devices to detect Saharan dust advections and evaluate their contribution to the PM10 levels: The EU LIFE+ "DIAPASON" project

NASA Astrophysics Data System (ADS)

Gobbi, Gian Paolo; Wille, Holger; Sozzi, Roberto; Barnaba, Francesca; Costabile, Francesca; Angelini, Federico; Frey, Steffen; Bolignano, Andrea; Morelli, Matteo

2013-04-01

The contribution of Saharan-dust advections to both daily and annual PM average mass concentrations can be significant all over Southern Europe. The Directive 2008/50/EC allows subtraction of PM10 exceedances caused by natural contributions from the statistic used to determine air-quality levels in Europe. To this purpose, the Commission Staff Working Paper 6771/11 (EC, 2011) provides specific Guidelines on methods to quantify and subtract the contribution of these sources in the framework of the Air Quality Directive. For Saharan dust, the EC methodology is largely based on a thorough analysis performed over the Iberian Peninsula (Escudero et al, 2007), although revision of the current methodology is in progress. In line with the EC Guidelines, the DIAPASON project ("Desert-dust Impact on Air quality through model-Predictions and Advanced Sensors ObservatioNs"), funded under the EC LIFE+ program, has been formulated to provide a robust, user-oriented, and demonstrated method to assess the presence of desert dust and evaluate its contribution to PM10 levels at the monitoring sites. To this end, in addition to satellite-based data and model forecasts already included in the EC Guidelines, DIAPASON will take advantage, in both the Project implementation and demonstration phase, of innovative and affordable technologies (partly prototyped within the project itself), namely operational Polarization Lidar-Ceilometers (PLC) capable of detecting and profiling dust clouds from the ground up to 10 km altitude. The PLC prototypes have been already finalized during the initial phase of the Project. Three of them will be networked in relevant air quality monitoring stations located in the Rome metropolitan area (Italy) during the DIAPASON observational phase (one-year long field campaign) starting in March 2013. The Rome region was chosen as the DIAPASON pilot scale area since highly impacted by urban pollution and frequently affected by Saharan dust transport events. In fact, a preliminary assessment of the role of Saharan dust in this area, based on a four-year dataset (2001-2004) has shown average increases of PM10 levels of the order of 11.9 µg/m3 when Saharan dust presence is either predicted by models or observed by a depolarization lidar. Conversely, PM10 increases computed relying only on the Lidar detections (i.e., presence of dust layers actually observed) were of the order of 15.6 µg/m3. Both analyses indicate the annual average contribution of dust advections to the city PM10 mass concentrations to be of the order of 2.3 µg/m3 (Gobbi et al., 2013). These results confirm Saharan advections in the central Mediterranean as important modulators of PM10 loads and exceedances. After the demonstrative pilot scale study, the DIAPASON results will be spatially generalised to a wider area. The final DIAPASON methodology to detect/quantify the Saharan dust contribution to PM10 will be tailored for a national scale application, and easily transferable to other air-quality and meteorological agencies in Europe. In this work, preliminary results from the combined analysis of Saharan dust model predictions, PM10 data and lidar records performed within DIAPASON will be shown, with particular focus on the added-value provided by continuous polarization lidar data in integrating the present EC Methodology. - EC, Commission Staff Working Paper 6771/11 establishing guidelines for demonstration and subtraction of exceedances attributable to natural sources under the Directive 2008/50/EC on ambient air quality and cleaner air for Europe, European Commission, 2011. - Escudero, M., Querol, X., Pey, J., Alastuey, A., Pérez, N., Ferreira, F., Alonso, S., Rodríguez, S. and Cuevas, E., A methodology for the quantification of the net African dust load in air quality monitoring networks, Atmos. Envir., 41, 5516-5524, 2007. - Gobbi,G. P., F. Angelini, F. Barnaba, F. Costabile, J. M. Baldasano, S. Basart, R. Sozzi and A. Bolignano, Changes in Particulate Matter Physical Properties During Saharan Advections over Rome (Italy): A Four-Year Study, 2001-2004, Atmos. Chem. Phys., Discus., 2013.

Source Identification Of Airborne Antimony On The Basis Of The Field Monitoring And The Source Profiling

NASA Astrophysics Data System (ADS)

Iijima, A.; Sato, K.; Fujitani, Y.; Fujimori, E.; Tanabe, K.; Ohara, T.; Shimoda, M.; Kozawa, K.; Furuta, N.

2008-12-01

The results of the long-term monitoring of airborne particulate matter (APM) in Tokyo indicated that APM have been extremely enriched with antimony (Sb) compared to crustal composition. This observation suggests that the airborne Sb is distinctly derived from human activities. According to the material flow analysis, automotive brake abrasion dust and fly ash from waste incinerator were suspected as the significant Sb sources. To clarify the emission sources of the airborne Sb, elemental composition, particle size distribution, and morphological profiles of dust particles collected from two possible emission sources were characterized and compared to the field observation data. Brake abrasion dust samples were generated by using a brake dynamometer. During the abrasion test, particle size distribution was measured by an aerodynamic particle sizer spectrometer. Concurrently, size- classified dust particles were collected by an Andersen type air sampler. Fly ash samples were collected from several municipal waste incinerators, and the bulk ash samples were re-dispersed into an enclosed chamber. The measurement of particle size distribution and the collection of size-classified ash particles were conducted by the same methodologies as described previously. Field observations of APM were performed at a roadside site and a residential site by using an Andersen type air sampler. Chemical analyses of metallic elements were performed by an inductively coupled plasma atomic emission spectrometry and an inductively coupled plasma mass spectrometr. Morphological profiling of the individual particle was conducted by a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. High concentration of Sb was detected from both of two possible sources. Particularly, Sb concentrations in a brake abrasion dust were extremely high compared to that in an ambient APM, suggesting that airborne Sb observed at the roadside might have been largely derived from mechanical abrasion of automotive brake pads. The peak of the mass-based particle size distribution of brake abrasion dust was found in a diameter of 2-3 μm. From the morphological viewpoints, shape of brake abrasion dust particle was typically edge- shaped, and high concentrated Sb and sulfur were simultaneously detected in a brake abrasion dust particle because Sb2S3 is used as a solid lubricant for automotive brake pad. Indeed, at the roadside site, total concentration of airborne Sb was twice as much as that observed at residential site. Moreover, the most concentrated Sb was found in a diameter of 2.1-3.6 μm for the roadside APM. Furthermore, in the collected particles with this size range, we found a number of particles of which morphological profiles were similar to those of the brake abrasion dust. Consequently, an automotive brake abrasion dust is expected as the predominant source of airborne Sb in the roadside atmosphere.

Rain chemistry and cloud composition and microphysics in a Caribbean tropical montane cloud forest under the influence of African dust

NASA Astrophysics Data System (ADS)

Torres-Delgado, Elvis; Valle-Diaz, Carlos J.; Baumgardner, Darrel; McDowell, William H.; González, Grizelle; Mayol-Bracero, Olga L.

2015-04-01

It is known that huge amounts of mineral dust travels thousands of kilometers from the Sahara and Sahel regions in Africa over the Atlantic Ocean reaching the Caribbean, northern South America and southern North America; however, not much is understood about how the aging process that takes place during transport changes dust properties, and how the presence of this dust affects cloud's composition and microphysics. This African dust reaches the Caribbean region mostly in the summer time. In order to improve our understanding of the role of long-range transported African dust (LRTAD) in cloud formation processes in a tropical montane cloud forest (TMCF) in the Caribbean region we had field campaigns measuring dust physical and chemical properties in summer 2013, as part of the Puerto Rico African Dust and Cloud Study (PRADACS), and in summer 2014, as a part of the Luquillo Critical Zone Observatory (LCZO) and in collaboration with the Saharan Aerosol Long-Range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE). Measurements were performed at the TMCF of Pico del Este (PE, 1051 masl) and at the nature reserve of Cabezas de San Juan (CSJ, 60 masl). In both stations we monitored meteorological parameters (e.g., temperature, wind speed, wind direction). At CSJ, we measured light absorption and scattering at three wavelengths (467, 528 and 652 nm). At PE we collected cloud and rainwater and monitored cloud microphysical properties (e.g., liquid water content, droplet size distribution, droplet number concentration, effective diameter and median volume diameter). Data from aerosol models, satellites, and back-trajectories were used together with CSJ measurements to classify air masses and samples collected at PE in the presence or absence of dust. Soluble ions, insoluble trace metals, pH and conductivity were measured for cloud and rainwater. Preliminary results for summer 2013 showed that in the presence of LRTAD (1) the average conductivity of cloud water was almost twice (81.1 μS/cm) as that in the absence of LRTAD (47.7 μS/cm), (2) the average conductivity in rainwater was slightly higher (15.0 μS/cm vs 12.8 μS/cm), and (3) the average pH was slightly higher for both cloud and rainwater samples (average of 6.41 for cloud water and 6.37 for rainwater). Detailed results on the chemical composition (water-soluble ions, trace metals, total organic carbon and total nitrogen) of cloud and rainwater, cloud microphysics, and on how these properties are affected in the presence of dust events will be presented at the meeting.

THE ALLEN TELESCOPE ARRAY SEARCH FOR ELECTROSTATIC DISCHARGES ON MARS

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

Anderson, Marin M.; Siemion, Andrew P. V.; Bower, Geoffrey C.

The Allen Telescope Array was used to monitor Mars between 2010 March 9 and June 2, over a total of approximately 30 hr, for radio emission indicative of electrostatic discharge. The search was motivated by the report from Ruf et al. of the detection of non-thermal microwave radiation from Mars characterized by peaks in the power spectrum of the kurtosis, or kurtstrum, at 10 Hz, coinciding with a large dust storm event on 2006 June 8. For these observations, we developed a wideband signal processor at the Center for Astronomy Signal Processing and Electronics Research. This 1024 channel spectrometer calculatesmore » the accumulated power and power-squared, from which the spectral kurtosis is calculated post-observation. Variations in the kurtosis are indicative of non-Gaussianity in the signal, which can be used to detect variable cosmic signals as well as radio frequency interference (RFI). During the three-month period of observations, dust activity occurred on Mars in the form of small-scale dust storms; however, no signals indicating lightning discharge were detected. Frequent signals in the kurtstrum that contain spectral peaks with an approximate 10 Hz fundamental were seen at both 3.2 and 8.0 GHz, but were the result of narrowband RFI with harmonics spread over a broad frequency range.« less

LETS: Lunar Environments Test System

NASA Technical Reports Server (NTRS)

Vaughn, Jason A.; Schneider, Todd; Craven, Paul; Norwood, Joey

2008-01-01

The Environmental Effects Branch (EM50) at the Marshall Space Flight Center has developed a unique capability within the agency, namely the Lunar Environment Test System (LETS). LETS is a cryo-pumped vacuum chamber facility capable of high vacuum (10-7 Torr). LETS is a cylindrical chamber, 30 in. (0.8 m) diameter by 48 in. (1.2 m) long thermally controlled vacuum system. The chamber is equipped with a full array of radiation sources including vacuum ultraviolet, electron, and proton radiation. The unique feature of LETS is that it contains a large lunar simulant bed (18 in. x 40 in. x 6 in.) holding 75 kg of JSC-1a simulant while operating at a vacuum of 10-7 Torr. This facility allows three applications: 1) to study the charging, levitation and migration of dust particles, 2) to simulate the radiation environment on the lunar surface, and 3) to electrically charge the lunar simulant enhancing the attraction and adhesion of dust particles to test articles more closely simulating the lunar surface dust environment. LETS has numerous diagnostic instruments including TREK electrostatic probes, residual gas analyzer (RGA), temperature controlled quartz crystal microbalance (TQCM), and particle imaging velocimeter (PIV). Finally, LETS uses continuous Labview data acquisition for computer monitoring and system control.

Correlation between Asian Dust and Specific Radioactivities of Fission Products Included in Airborne Samples in Tokushima, Shikoku Island, Japan, Due to the Fukushima Nuclear Accident

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

Sakama, M., E-mail: minorusakama@tokushima-u.ac.jp; Nagano, Y.; Kitade, T.

2014-06-15

Radioactive fission product {sup 131}I released from the Fukushima Daiichi Nuclear Power Plants (FD-NPP) was first detected on March 23, 2011 in an airborne aerosol sample collected at Tokushima, Shikoku Island, located in western Japan. Two other radioactive fission products, {sup 134}Cs and {sup 137}Cs were also observed in a sample collected from April 2 to 4, 2011. The maximum specific radioactivities observed in this work were about 2.5 to 3.5 mBq×m{sup -3} in a airborne aerosol sample collected on April 6. During the course of the continuous monitoring, we also made our first observation of seasonal Asian Dust andmore » those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of {sup 134}Cs and {sup 137}Cs decreased drastically only during the period of Asian Dust. And also, it was found that this trend was very similar to the atmospheric elemental concentration (ng×m{sup -3}) variation of stable cesium ({sup 133}Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument.« less

Tonopah Test Range Air Monitoring: CY2015 Meteorological, Radiological, and Airborne Particulate Observations

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

Nikolich, George; Shadel, Craig; Chapman, Jenny

2016-09-01

In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). The operation resulted in radionuclide-contaminated soils at the Clean Slate I, II, and III sites. This report documents observations made during ongoing monitoring of radiological, meteorological, and dust conditions at stations installed adjacent to Clean Slate I and Clean Slate III, and at the TTR Sandia National Laboratories (SNL) Range Operations Control (ROC) center. The primary objective ofmore » the monitoring effort is to determine if winds blowing across the Clean Slate sites are transporting particles of radionuclide-contaminated soil beyond the physical and administrative boundaries of the sites. Radionuclide assessment of airborne particulates in 2015 found the gross alpha and gross beta values of dust collected from the filters at the monitoring stations are consistent with background conditions. The meteorological and particle monitoring indicate that conditions for wind-borne contaminant movement exist at the Clean Slate sites and that, although the transport of radionuclide-contaminated soil by suspension has not been detected, movement by saltation is occurring.« less

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

10 CFR 850.29 - Protective clothing and equipment.

Code of Federal Regulations, 2014 CFR

2014-01-01

...' eyes, including where: (1) Exposure monitoring has established that airborne concentrations of... containers that prevent the dispersion of beryllium dust and that are labeled in accordance with § 850.38 of...

10 CFR 850.29 - Protective clothing and equipment.

Code of Federal Regulations, 2012 CFR

2012-01-01

...' eyes, including where: (1) Exposure monitoring has established that airborne concentrations of... containers that prevent the dispersion of beryllium dust and that are labeled in accordance with § 850.38 of...

10 CFR 850.29 - Protective clothing and equipment.

Code of Federal Regulations, 2013 CFR

2013-01-01

...' eyes, including where: (1) Exposure monitoring has established that airborne concentrations of... containers that prevent the dispersion of beryllium dust and that are labeled in accordance with § 850.38 of...

Monitoring of mirror degradation of fluorescence detectors at the Pierre Auger Observatory due to dust sedimentation

NASA Astrophysics Data System (ADS)

Nozka, L.; Hiklova, H.; Horvath, P.; Hrabovsky, M.; Mandat, D.; Palatka, M.; Pech, M.; Ridky, J.; Schovanek, P.

2018-05-01

We present results of the monitoring method we have used to characterize the optical performance deterioration due to the dust of our mirror segments produced for fluorescence detectors used in astrophysics experiments. The method is based on the measurement of scatter profiles of reflected light. The scatter profiles and the reflectivity of the mirror segments sufficiently describe the performance of the mirrors from the perspective of reconstruction algorithms. The method is demonstrated on our mirror segments installed in frame of the Pierre Auger Observatory project. Although installed in air-conditioned buildings, both the dust sedimentation and the natural aging of the reflective layer deteriorate the optical throughput of the segments. In the paper, we summarized data from ten years of operation of the fluorescence detectors. During this time, we periodically measured in-situ scatter characteristics represented by the specular reflectivity and the reflectivity of the diffusion part at the wavelength of 670 nm of the segment surface (measured by means of the optical scatter technique as well). These measurements were extended with full Bidirectional Reflectance Distribution Functions (BRDF) profiles of selected segments made in the laboratory. Cleaning procedures are also discussed in the paper.

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.

Electrostatic Charging of Lunar Dust by UV Photoelectric Emissions and Solar Wind Electrons

NASA Technical Reports Server (NTRS)

Abbas, Mian M.; Tankosic, Dragana; Spann, James f.; LeClair, Andre C.; Dube, Michael J.

2008-01-01

The ubiquitous presence of dust in the lunar environment with its high adhesive characteristics has been recognized to be a major safety issue that must be addressed in view of its hazardous effects on robotic and human exploration of the Moon. The reported observations of a horizon glow and streamers at the lunar terminator during the Apollo missions are attributed to the sunlight scattered by the levitated lunar dust. The lunar surface and the dust grains are predominantly charged positively by the incident UV solar radiation on the dayside and negatively by the solar wind electrons on the night-side. The charged dust grains are levitated and transported over long distances by the established electric fields. A quantitative understanding of the lunar dust phenomena requires development of global dust distribution models, based on an accurate knowledge of lunar dust charging properties. Currently available data of lunar dust charging is based on bulk materials, although it is well recognized that measurements on individual dust grains are expected to be substantially different from the bulk measurements. In this paper we present laboratory measurements of charging properties of Apollo 11 & 17 dust grains by UV photoelectric emissions and by electron impact. These measurements indicate substantial differences of both qualitative and quantitative nature between dust charging properties of individual micron/submicron sized dust grains and of bulk materials. In addition, there are no viable theoretical models available as yet for calculation of dust charging properties of individual dust grains for both photoelectric emissions and electron impact. It is thus of paramount importance to conduct comprehensive measurements for charging properties of individual dust grains in order to develop realistic models of dust processes in the lunar atmosphere, and address the hazardous issues of dust on lunar robotic and human missions.

A Dust Devil Making a Streak and Climbing a Crater Wall

NASA Technical Reports Server (NTRS)

2002-01-01

MGS MOC Release No. MOC2-318, 8 August 2002 [figure removed for brevity, see original site] One of the key elements of the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) Extended Mission is to look for and monitor changes taking place on the planet over the course of a second--and, eventually, a third--martian year. MGS is now well into its second Mars year, which will draw to a close in December 2002. Among the changes the MOC has observed are streaks believed to be caused by the passage of dust devils. Thousands of MOC images show these streaks, dozens show that they change over time, but far fewer images have actually captured a dust devil in the act of creating a streak. At the center right of this image (above left) is a dust devil that, on May 21, 2002, was seen climbing the wall of a crater at 4.1oS, 9.5oW. This crater (above right) is in western Terra Meridiani. The dust devil was moving toward the northeast (upper right), leaving behind a dark trail where a thin coating of surficial dust was removed or disrupted as the dust devil advanced. Dust devils most commonly form after noon on days when the martian air is still (that is, when there isn't even a faint breeze). On such days, the ground is better able to heat up the air immediately above the surface. As the warmed near-surface air begins to rise, it also begins to spin, creating a vortex. The spinning column then moves across the surface and picks up loose dust (if any is present). The dust makes the vortex visible and gives it a tornado-like appearance. The dust devil in this image has a very short, dark shadow cast to the right of the bright column; this shadow is short because the sun was nearly overhead.

Infrared emission from tidal disruption events - probing the pc-scale dust content around galactic nuclei

NASA Astrophysics Data System (ADS)

Lu, Wenbin; Kumar, Pawan; Evans, Neal J.

2016-05-01

Recent UV-optical surveys have been successful in finding tidal disruption events (TDEs), in which a star is tidally disrupted by a supermassive black hole (BH). These TDEs release a huge amount of radiation energy Erad ˜ 1051-1052 erg into the circum-nuclear medium. If the medium is dusty, most of the radiation energy will be absorbed by dust grains within ˜1 pc from the BH and re-radiated in the infrared. We calculate the dust emission light curve from a 1D radiative transfer model, taking into account the time-dependent heating, cooling and sublimation of dust grains. We show that the dust emission peaks at 3-10 μm and has typical luminosities between 1042 and 1043 erg s-1 (with sky covering factor of dusty clouds ranging from 0.1 to 1). This is detectable by current generation of telescopes. In the near future, James Webb Space Telescope will be able to perform photometric and spectroscopic measurements, in which silicate or polycyclic aromatic hydrocarbon features may be found. Dust grains are non-spherical and may be aligned with the magnetic field, so the dust emission may be significantly polarized. Observations at rest-frame wavelength ≥ 2 μm have only been reported from two TDE candidates, SDSS J0952+2143 and SwiftJ1644+57. Although consistent with the dust emission from TDEs, the mid-infrared fluxes of the two events may be from other sources. Long-term monitoring is needed to draw a firm conclusion. We also point out two nearby TDE candidates (ASASSN-14ae and -14li) where the dust emission may be currently detectable. Detection of dust infrared emission from TDEs would provide information regarding the dust content and its distribution in the central pc of non-active galactic nuclei, which is hard to probe otherwise.

ACS Internal Flat Fields

NASA Astrophysics Data System (ADS)

Borncamp, David

2017-08-01

The stability of the CCD flat fields will be monitored using the calibration lamps. One set of observations for all the filters and another at a different epoch for a subset of filters will be taken during this cycle. High signal observations will be used to assess the stability of the pixel-to-pixel flat field structure and to monitor the position of the dust motes.

ACS Internal Flat Fields

NASA Astrophysics Data System (ADS)

Borncamp, David

2016-10-01

The stability of the CCD flat fields will be monitored using the calibration lamps. One set of observations for all the filters and another at a different epoch for a subset of filters will be taken during this cycle. High signal observations will be used to assess the stability of the pixel-to-pixel flat field structure and to monitor the position of the dust motes.

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.

Optical measures of dust velocities and direction during loss of vacuum accidents in confined environment and correlation between dust positions and properties with the resuspension degrees and the velocity modules

NASA Astrophysics Data System (ADS)

Andrea, Malizia; Rossi, Riccardo; Gaudio, Pasquale

2017-08-01

Dust explosions are dangerous events that still today represent a risk to all the industries that produce and/or handle combustible dust like the agro-alimentary, pharmaceutical and energy ones. When a dust cloud is dispersed in an oxidant gas, like air, it may reach the explosive concentration range. A model to predict the dust critical conditions, that can cause explosions, is a key factor for safety of operators and the security of the plants. The key point to predict this dust resuspension is to measure the velocity vectors of dust under the accidental conditions. In order to achieve this goal the authors have developed an experimental facility, STARDUST-U, which allow to obtain different conditions of temperature and pressurization rates characteristic of accidents in confined environment. The authors have developed also optical methods and software to analyse different dust resuspension phenomena under different conditions in confined environment. In this paper, the author will present how they measure the dust velocity vectors in different experimental conditions (and for different type of dusts) and how they have related the dust characteristics and positions inside STARDUST-U with the resuspension degree and the velocity values.

Mimicking Mars: a vacuum simulation chamber for testing environmental instrumentation for Mars exploration.

PubMed

Sobrado, J M; Martín-Soler, J; Martín-Gago, J A

2014-03-01

We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10(-6) mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.

Evaluation of Microbiological and Chemical Contaminants in Poultry Farms.

PubMed

Skóra, Justyna; Matusiak, Katarzyna; Wojewódzki, Piotr; Nowak, Adriana; Sulyok, Michael; Ligocka, Anna; Okrasa, Małgorzata; Hermann, Janusz; Gutarowska, Beata

2016-02-04

The aim of the study was to evaluate the microbiological and chemical contamination in settled dust at poultry farms. The scope of research included evaluating the contributions of the various granulometric fractions in settled dust samples, assessing microbial contamination using culture methods, concentrations of secondary metabolites in dust and their cytotoxicity against hepatocyte chicken cells by means of MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) tests. In addition, we also evaluated the concentration of selected volatile odorous compounds (VOCs) using gas chromatographic and spectrophotometric methods and airborne dust concentration in the air with DustTrak™ DRX Aerosol Monitor. Studies were carried out on chicken broilers and laying hens at 13 poultry farms, with numbers of birds ranging from 8000 to 42,000. The airborne total dust concentration at poultry farms averaged 1.44 mg/m³ with a high percentage of the PM10 fraction (particulate matter with a diameter less than 10 μm). Microorganism concentrations in the settled dust were: 3.2 × 10⁸ cfu/g for bacteria and 1.2 × 10⁶ cfu/g for fungi. Potential pathogens (Enterococcus spp., Escherichia coli, Salmonella spp., Aspergillus fumigatus, Paecilomyces variotii) were also found. Secondary metabolites included aurofusarin, deoxynivalenol, 15-hydroxyculmorin zearalenone, zearalenone-sulfate, infectopyron, and neochinulin A. However, the dust samples showed weak cytotoxicity towards chicken hepatocyte cells, which ranged between 9.2% and 29.7%. Among volatile odorous compounds ammonia, acrolein, methyloamine, acetic acid, acetoaldehyde and formaldehyde were detected in the air. In conclusion, settled dust can be a carrier of microorganisms, odours and secondary metabolites in poultry farms, which can be harmful to workers' health.

Evaluation of Microbiological and Chemical Contaminants in Poultry Farms

PubMed Central

Skóra, Justyna; Matusiak, Katarzyna; Wojewódzki, Piotr; Nowak, Adriana; Sulyok, Michael; Ligocka, Anna; Okrasa, Małgorzata; Hermann, Janusz; Gutarowska, Beata

2016-01-01

The aim of the study was to evaluate the microbiological and chemical contamination in settled dust at poultry farms. The scope of research included evaluating the contributions of the various granulometric fractions in settled dust samples, assessing microbial contamination using culture methods, concentrations of secondary metabolites in dust and their cytotoxicity against hepatocyte chicken cells by means of MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) tests. In addition, we also evaluated the concentration of selected volatile odorous compounds (VOCs) using gas chromatographic and spectrophotometric methods and airborne dust concentration in the air with DustTrak™ DRX Aerosol Monitor. Studies were carried out on chicken broilers and laying hens at 13 poultry farms, with numbers of birds ranging from 8000 to 42,000. The airborne total dust concentration at poultry farms averaged 1.44 mg/m3 with a high percentage of the PM10 fraction (particulate matter with a diameter less than 10 μm). Microorganism concentrations in the settled dust were: 3.2 × 109 cfu/g for bacteria and 1.2 × 106 cfu/g for fungi. Potential pathogens (Enterococcus spp., Escherichia coli, Salmonella spp., Aspergillus fumigatus, Paecilomyces variotii) were also found. Secondary metabolites included aurofusarin, deoxynivalenol, 15-hydroxyculmorin zearalenone, zearalenone-sulfate, infectopyron, and neochinulin A. However, the dust samples showed weak cytotoxicity towards chicken hepatocyte cells, which ranged between 9.2% and 29.7%. Among volatile odorous compounds ammonia, acrolein, methyloamine, acetic acid, acetoaldehyde and formaldehyde were detected in the air. In conclusion, settled dust can be a carrier of microorganisms, odours and secondary metabolites in poultry farms, which can be harmful to workers’ health. PMID:26861361

Properties of Arizona Dust Devils: a Martian Analog

NASA Astrophysics Data System (ADS)

Smith, P. H.; Renno, N.; MATADOR Team

2001-11-01

During the week of June 4-8, 2001, the MATADOR team instrumented a truck to study the properties of dust devils at a Martian analog site in Eloy, AZ. MATADOR consists of a group of instruments operated by a science team of about 20 members originally selected by the HEDS program for a 2003 lander mission to Mars. Currently deselected with the loss of the mission, the team has continued studying the optimum means for measuring dust devil properties. With an eye for remotely sensing and identifying potential hazards to humans and their equipment, MATADOR can eventually act as an early warning system much like tornedo and hurricane watches on the Earth. Key questions that the MATADOR group is addressing concern the ability of LIDAR (provided by Optech in Canada) to scan dust devils, the strength of electrical charging and the associated E-fields that are created, the oxidation of the local soil from ionized species, and the best ways to measure the quixotic meteorological properties that define dust devils. Dozens of dust devils were monitored during the field test both remotely and in situ, the results of our study will be presented in detail. One thing is clear though, dust devils maintain a tremendous charge separation such that E-fields approach the breakdown potential of the Earth's atmosphere. Equivalent dust devils on Mars would be 100 times larger than their small Earth cousins; despite the much reduced breakdown potential of the Martian atmosphere, charge separations are likely to occur on Mars. The discharging of these dust events would create electrical signals that can be studied remotely. We would like to thank NASA's HEDS division for their support of these investigations.

Highlights and discoveries of the Cosmic Dust Analyser (CDA) during its 15 years of exploration

NASA Astrophysics Data System (ADS)

Srama, R.; Moragas-Klostermeyer, G.; Kempf, S.; Postberg, F.; Albin, T.; Auer, S.; Altobelli, N.; Beckmann, U.; Bugiel, S.; Burton, M.; Economou, T.; Fliege, K.; Grande, M.; Gruen, E.; Guglielmino, M.; Hillier, J. K.; Schilling, A.; Schmidt, J.; Seiss, M.; Spahn, F.; Sterken, V.; Trieloff, M.

2014-04-01

The interplanetary space probe Cassini/Huygens reached Saturn in July 2004 after seven years of cruise phase. Today, the German-lead Cosmic Dust Analyser (CDA) is operated continuously for 10 years in orbit around Saturn. During the cruise phase CDA measured the interstellar dust flux at one AU distance from the Sun, the charge and composition of interplanetary dust grains and the composition of the Jovian nanodust streams. The first discovery of CDA related to Saturn was the measurement of nanometer sized dust particles ejected by its magnetosphere to interplanetary space with speeds higher than 100 km/s. Their origin and composition was analysed and an their dynamical studies showed a strong link to the conditions of the solar wind plasma flow. A recent surprising result was, that stream particles stem from the interior of Enceladus. Since 2004 CDA measured millions of dust impacts characterizing the dust environment of Saturn. The instrument showed strong evidence for ice geysers located at the south pole of Saturn's moon Enceladus in 2005. Later, a detailed compositional analysis of the salt-rich water ice grains in Saturn's E ring system lead to the discovery of liquid water below the icy crust connected to an ocean at depth feeding the icy jets. CDA was even capable to derive a spatially resolved compositional profile of the plume during close Enceladus flybys. A determination of the dust-magnetosphere interaction and the discovery of the extended E ring allowed the definition of a dynamical dust model of Saturn's E ring describing the observed properties. The measured dust density profiles in the dense E ring revealed geometric asymmetries. Cassini performed shadow crossings in the ring plane and dust grain charges were measured in shadow regions delivering important data for dust-plasma interaction studies. In the last years, dedicated measurement campaigns were executed by CDA to monitor the flux of interplanetary and interstellar dust particles reaching Saturn. Currently, the composition of interstellar grains and the meteoroid flux into the Saturnian system are in analysis.

Improving Air Pollution Modeling Over The Po Valley Using Saharan Dust Transport Forecasts

NASA Astrophysics Data System (ADS)

Kishcha, P.; Carnevale, C.; Finzi, G.; Pisoni, E.; Volta, M.; Nickovic, S.; Alpert, P.

2012-04-01

Our study shows that Saharan dust can contribute significantly to PM10 concentrations in the Po Valley. This dust contribution should be taken into account when estimating the exceedance of pollution limits. The DREAM dust model has been used for several years for producing operational dust forecasts at Tel-Aviv University, Israel. DREAM has been producing daily forecasts of 3-D distribution of dust concentrations over the Mediterranean region, Middle East, Europe, and over the Atlantic Ocean (http://wind.tau.ac.il/dust8/dust.html). In the current study, DREAM dust forecasts were used to give better model estimates of the contribution of Saharan dust to PM10 concentration over the Po Valley, in Northern Italy. This was carried out by the integration of daily Saharan dust forecasts into a mesoscale Transport Chemical Aerosol Model (TCAM). The Po Valley in Northern Italy is frequently affected by high PM10 concentrations, where both natural and anthropogenic sources play a significant role. Our study of TCAM and DREAM integration was carried out for the period May 15 - June 30, 2007, when four significant dust events were observed. The integrated TCAM-DREAM model performance was evaluated by comparing PM10 measurements with modeled PM10 concentrations. First, Saharan dust impact on TCAM performance was analyzed at eleven remote PM10 sites which had the lowest level of air pollution (PM10 ≤ 14 μg/m3) over the period under consideration. For those remote sites, the observed high PM10 concentrations during dust events stood prominently on the background of low PM10 concentrations. At the remote sites, such a strong deviation from the background level can not be attributed to anthropogenic aerosol emissions because of their distance from anthropogenic sources. The observed maxima in PM10 concentration during dust events is evidence of dust aerosol near the surface in Northern Italy. During all dust events under consideration, the integrated TCAM-DREAM model produced more accurate PM10 concentrations than the base TCAM model. Then, a comparison between modeled concentrations and PM10 measurements was carried out at 230 PM10 monitoring sites, distributed within the model domain. This model-vs.-measurement comparison showed that the integrated TCAM -DREAM model more accurately reproduced PM10 concentrations than the base TCAM model, both in term of correlation and mean error. Our results are of importance to countries which have to pay a penalty for exceeding the pollution limit. By extracting dust contribution from PM10 measurements, these countries could show lower rates of man-made pollution.

Understanding the impact of saharan dust aerosols on tropical cyclones

NASA Astrophysics Data System (ADS)

Naeger, Aaron

Genesis of Tropical Cyclones (TCs) in the main development region for Atlantic hurricanes is tied to convection initiated by African easterly waves (AEWs) during Northern hemisphere summer and fall seasons. The main development region is also impacted by dust aerosols transported from the Sahara. It has been hypothesized that dust aerosols can modulate the development of TCs through aerosol-radiation and aerosol-cloud interaction processes. In this study, we investigate the impact of dust aerosols on TC development using the Weather Research and Forecasting model coupled with chemistry (WRF-Chem). We first develop a technique to constrain the WRF-Chem model with a realistic three-dimensional spatial distribution of dust aerosols. The horizontal distribution of dust is specified using the Moderate Resolution Imaging Spectroradiometer (MODIS) derived aerosol products and output from the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. The vertical distribution of dust is constrained using the Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). We validate our technique through in situ aircraft measurements where both showed aerosol number concentrations from 20-30 cm-3 in the atmosphere for Saharan dust moving over the eastern Atlantic Ocean. Then, we use the satellite data constraint technique to nudge the WRF-Chem aerosol fields throughout the simulation of TC Florence developing over the eastern Atlantic Ocean during September 2006. Three different experiments are conducted where the aerosol-radiation and aerosol-cloud interaction processes are either activated or deactivated in the model while all other model options are identical between the experiments. By comparing the model experiment results, the impact of the aerosol interaction processes on TC development can be understood. The results indicate that dust aerosols can delay or prevent the development of a TC as the minimum sea level pressure of TC Florence was 13 hPa higher when the aerosols interactions were activated as opposed to deactivated in the model.

Electrodynamic Dust Shield for Surface Exploration Activities on the Moon and Mars

NASA Technical Reports Server (NTRS)

Calle, C. I.; Immer, C. D.; Clements, J. S.; Chen, A.; Buhler, C. R.; Lundeen, P.; Mantovani, J. G.; Starnes, J. W.; Michalenko, M.; Mazumder, M. K.

2006-01-01

The Apollo missions to the moon showed that lunar dust can hamper astronaut surface activities due to its ability to cling to most surfaces. NASA's Mars exploration landers and rovers have also shown that the problem is equally hard if not harder on Mars. In this paper, we report on our efforts to develop and electrodynamic dust shield to prevent the accumulation of dust on surfaces and to remove dust already adhering to those surfaces. The parent technology for the electrodynamic dust shield, developed in the 1970s, has been shown to lift and transport charged and uncharged particles using electrostatic and dielectrophoretic forces. This technology has never been applied for space applications on Mars or the moon due to electrostatic breakdown concerns. In this paper, we show that an appropriate design can prevent the electrostatic breakdown at the low Martian atmospheric pressures. We are also able to show that uncharged dust can be lifted and removed from surfaces under simulated Martian environmental conditions. This technology has many potential benefits for removing dust from visors, viewports and many other surfaces as well as from solar arrays. We have also been able to develop a version of the electrodynamic dust shield working under. hard vacuum conditions. This version should work well on the moon.

Trans-Pacific yellow sand transport observed in April 1998: A numerical simulation

NASA Astrophysics Data System (ADS)

Uno, Itsushi; Amano, Hiroyasu; Emori, Seita; Kinoshita, Kisei; Matsui, Ichiro; Sugimoto, Nobuo

2001-08-01

A yellow sand transport episode from the Asian continent to Japan and North America which occurred in April 1998 is simulated. A new on-line dust tracer model coupled with a regional-scale meteorological model is developed and applied to this dust storm episode. The results for two large dust events that started during April 14-15 and 19-20, 1998, have been analyzed and discussed. The first dust storm was trapped in a cutoff vortex developed over the China plain. A modeled 3-D structure of dust associated with this cutoff vortex agreed with an observed time-height cross section of dust concentration. Results show that the strong subsidence at the backside of the vortex restricted the dust layer below 3 km level. Model analysis revealed that the second dust event that started during April 19-20 over inland China was the origin of a dust episode reported over North America. The trans-Pacific dust transport simulation successfully showed the dust onset near the West Coast of North America. Elevation of the dust layer during the long-range transport was below 3 km. The model is extended to include the transport of an Asian origin anthropogenic tracer over the North Pacific Rim. Both the natural-origin mineral dust and the Asian-origin anthropogenic tracer are simultaneously transported even if their emission regions are different.

Mars Global Surveyor Thermal Emission Spectrometer (TES) Observations of Dust Opacity During Aerobraking and Science Phasing

NASA Technical Reports Server (NTRS)

Smith, Michael D.; Pearl, John C.; Conrath, Barney J.; Christensen, Philip R.

1999-01-01

The Mars Global Surveyor (MGS) arrived at Mars in September 1997 near Mars southern spring equinox and has now provided monitoring of conditions in the Mars atmosphere for more than half a Mars year. The large majority of the spectra taken by the Thermal Emission Spectrometer (TES) are in a nadir geometry (downward looking mode) where Mars is observed through the atmosphere. Most of these contain the distinct spectral signature of atmospheric dust. For these nadir-geometry spectra we retrieve column-integrated infrared aerosol (dust) opacities. TES observations during the aerobraking and science-phasing portions of the MGS mission cover the seasonal range L(sub s)=184 deg - 28 deg. Excellent spatial coverage was obtained in the southern hemisphere. Northern hemisphere coverage is generally limited to narrow strips taken during the periapsis pass but is still very valuable. At the beginning of the mission the 9-(micron)meter dust opacity at midsouthern latitudes was low (0.15-0.25). As the season advanced through southern spring and into summer, TES observed several regional dust storms (including the Noachis dust storm of November 1997) where peak 9-(micron)meter dust opacities approached or exceeded unity, as well as numerous smaller local storms. Both large and small dust storms exhibited significant changes in both spatial coverage and intensity over a timescale of a day. Throughout southern spring and summer the region at the edge of the retreating southern seasonal polar ice cap was observed to be consistently more dusty than other latitudes.

Characteristics of aerosol and meteorological parameters during major dust storm events (2005 - 2010) over Beijing, China

NASA Astrophysics Data System (ADS)

Zheng, Sheng; Cao, Chunxiang; Singh, Ramesh

Multi satellite sensors are capable in monitoring dust storm, its path and changes in atmospheric parameters. The present paper discusses aerosol optical properties and meteorological parameters during major dust storm events (2005-2010) over Beijing, China. The back trajectory model shows that the dust is transported from the Inner Mongolia and Mongolia to Beijing. High aerosol optical depth (AOD) and low Ångström exponent (AE) values are observed during dusty days, the average AOD (675 nm) and AE (440-870 nm) during dusty days are 2.33 and 0.06, respectively. The aerosol size distribution (ASD) in coarse mode shows a large increase in the volume during dusty days. The single scattering albedo (SSA) increases with higher wavelength on dusty days, and higher compared to non-dusty days, indicating the presence of high scattering particles due to dust storm events. Characteristics of particles during dusty and non-dusty days are also supported by the real and imaginary parts of refractive index (RI). High air pollution index (API) during dusty days represent poor air quality is a serious health hazard at the time of dust events. The CO volume mixing ratio (COVMR) from Atmospheric Infrared Sounder (AIRS) shows decrease on the ground on dusty days, while the relative humidity (RH) and H _{2}0 mass mixing ratio (H _{2}OMMR) enhance. In addition, due to the dust storm in 2005, enhanced level of water vapor (WV) using Moderate Resolution Imaging Spectroradiometer (MODIS) data is observed in and around Beijing over the dust storms track.

Asian Dust Storm Outbreaks: A Satellite-Surface Perspective

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee

2006-01-01

Airborne dusts from northern China contribute a significant part of the air quality problem and, to some extent, regional climatic impact in Asia during springtime. Asian dust typically originates in desert areas far from polluted urban regions. During the transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian dust is of special importance in regional-to-global climate issues (e.g., radiative forcing, hydrological cycle, and primary biological productivity in the mid-Pacific Ocean, etc.), as well as societal concerns (e.g., adverse health effects to humans). The Asian dust and air pollution aerosols can be detected by its colored appearance on current Earth observing satellites (e.g., MODIS, SeaWiFS, TOMS, etc.) and its evolution monitored by satellites and surface network (e.g. AERONET, SKY NET, MPLNET, etc.). Recently, many field campaigns (e.g., ACE-Asia-2001, TRACEP-2001, ADE-2002 & -2003, APEX-2001 & -2003, etc.) were designed and executed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentrations over eastern Asia and along the rim of the western Pacific. I will present an overview of the outbreak of Asian dust storms from space and surface observations and to address the climatic effects and societal impacts.

DART: Instrument Package Developed for Investigating Atmospheric Dust on Mars

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2001-01-01

Mars' dust-filled atmosphere could be a significant problem for photovoltaic array operation during long missions on the surface of Mars. Measurements made by Pathfinder showed a 0.3-percent loss of solar array performance per day due to dust obscuration. Thus, dust deposition is the limiting factor in the lifetime of solar arrays for Martian power systems, and developing design tools to mitigate this deposition is important for long missions.

Biomarkers of exposure to metal dust in exhaled breath condensate: methodology optimization.

PubMed

Félix, P M; Franco, C; Barreiros, M A; Batista, B; Bernardes, S; Garcia, S M; Almeida, A B; Almeida, S M; Wolterbeek, H Th; Pinheiro, T

2013-01-01

In occupational assessments where workers are exposed to metal dust, the liquid condensate of exhaled breath (EBC) may provide unique indication of pulmonary exposure. The main goal of this study was to demonstrate the quality of EBC to biological monitoring of human exposure. A pilot study was performed in a group of metal dust-exposed workers and a group of nonexposed individuals working in offices. Only metal dust-exposed workers were followed along the working week to determine the best time of collection. Metal analyses were performed with inductively coupled plasma mass spectrometry (ICP-MS). Analytical methodology was tested using an EBC sample pool for several occupationally exposed metals: potassium, chromium, manganese, copper, zinc, strontium, cadmium, antimony, and lead. Metal contents in EBC of exposed workers were higher than controls at the beginning of the shift and remained augmented throughout the working week. The results obtained support the establishment of EBC as an indicator of pulmonary exposure to metals.

Electrodynamic Dust Shields on the International Space Station: Exposure to the Space Environment

NASA Technical Reports Server (NTRS)

Calle, C. I.; Hogue, M. D.; Johansen, M. R.; Yim, H.; Delaune, P. B.; Clements, J. S.

2012-01-01

Electrodynamic Dust Shields (EDS) have been in development at NASA as a dust mitigation method for lunar and Martian missions. An active dust mitigation strategy. such as that provided by the EDS, that can remove dust from surfaces, is of crucial importance to the planetary exploration program. We report on the development of a night experiment to fully ex pose four EDS panels to the space environment. This flight experiment is part of the Materials International Space Station experiment X(MISSE-X). an external platform on the International Space Station that will expose materials to the space environment.

DustEM: Dust extinction and emission modelling

NASA Astrophysics Data System (ADS)

Compiègne, M.; Verstraete, L.; Jones, A.; Bernard, J.-P.; Boulanger, F.; Flagey, N.; Le Bourlot, J.; Paradis, D.; Ysard, N.

2013-07-01

DustEM computes the extinction and the emission of interstellar dust grains heated by photons. It is written in Fortran 95 and is jointly developed by IAS and CESR. The dust emission is calculated in the optically thin limit (no radiative transfer) and the default spectral range is 40 to 108 nm. The code is designed so dust properties can easily be changed and mixed and to allow for the inclusion of new grain physics.

Deducing dust emission mechanisms from field measurements

USDA-ARS?s Scientific Manuscript database

Field observations are needed to both develop and test theories on dust emission for use in global modeling systems. The mechanism of dust emission (aerodynamic entrainment, saltation bombardment, aggregate disintegration) and the amount and particle-size distribution of emitted dust may vary under ...

Evaluation of the SKC DPM cassette for monitoring diesel particulate matter in coal mines.

PubMed

Noll, James D; Birch, Eileen

2004-12-01

In a previous study, the efficacy of commercial and prototype impactors for sampling diesel particulate matter (DPM) in coal mines was investigated. Laboratory and field samples were collected on quartz-fiber filters and analyzed for organic and elemental carbon. Coal dust contributed a minimal amount of elemental carbon when commercial cascade impactors and prototype impactors, designed by the University of Minnesota (UMN) and the US Bureau of Mines (BOM), were used to collect submicrometer dust fractions. Other impactors were not as effective at excluding coal dust. The impactors evaluated in that study were either not commercially available or were multi-stage, expensive, and difficult to use for personal measurements. A commercial version of the BOM impactor, called the DPM Cassette, was recently introduced by SKC. Tests were conducted to evaluate the performance of the DPM Cassette for measuring diesel-source elemental carbon in the presence of coal dust. Bituminous coals from three mines in two different coal provinces were examined. The dust particle diameters were small and the coal dust contained a high percentage of carbon, thereby giving a worst-case condition for non-anthracite coal mines. Results for the DPM Cassette were essentially identical to those obtained by the BOM impactors in a previous study. At a respirable coal dust concentration of 5.46 mg m(-3), which is 3.8 times the regulatory limit, the DPM Cassette collected only 34 microg m(-3) of coal-source elemental carbon.

Regional prediction of carbon isotopes in soil carbonates for Asian dust source tracer

NASA Astrophysics Data System (ADS)

Chen, Bing; Cui, Xinjuan; Wang, Yaqiang

2016-10-01

Dust particles emitted from deserts and semi-arid lands in northern China cause particulate pollution that increases the burden of disease particularly for urban population in East Asia. The stable carbon isotopes (δ13C) of carbonates in soils and dust aerosols in northern China were investigated. We found that the δ13C of carbonates in surface soils in northern China showed clearly the negative correlation (R2 = 0.73) with Normalized Difference Vegetation Index (NDVI). Using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-derived NDVI, we predicted the regional distribution of δ13C of soil carbonates in deserts, sandy lands, and steppe areas. The predictions show the mean δ13C of -0.4 ± 0.7‰ in soil carbonates in Taklimakan Desert and Gobi Deserts, and the isotope values decrease to -3.3 ± 1.1‰ in sandy lands. The increase in vegetation coverage depletes 13C in soil carbonates, thus the steppe areas are predicted by the lowest δ13C levels (-8.1 ± 1.7‰). The measurements of atmospheric dust samples at eight sites showed that the Asian dust sources were well assigned by the 13C mapping in surface soils. Predicting 13C in large geographical areas with fine resolution offers a cost-effective tracer to monitor dust emissions from sandy lands and steppe areas which show an increasing role in Asian dust loading driven by climate change and human activities.

Overview on relative importance of house dust ingestion in human exposure to polybrominated diphenyl ethers (PBDEs): International comparison and Korea as a case.

PubMed

Kim, Seung-Kyu; Kim, Kyoung-Soo; Sang, Hee Hong

2016-11-15

Human exposure studies to polybrominated diphenyl ethers (PBDEs) have reached different results about the relative importance of diet intake and house dust ingestion. In the present study, concentrations of PBDEs in Korean house dust (n=15) from geographically different cities were measured, which were in agreement with a previous result, and compared with those for 22 countries of five continents collected from the most recent scientific literature. Compared with other exposure pathways, diet intake was the most important contributor to total PBDEs exposure of Korean adults (i.e., 71% of overall intake). On global comparison, total PBDE levels in house dust differed by two to three orders of magnitude among the countries investigated, with a significant relationship with gross domestic product (GDP). Whereas, dietary daily intakes exhibited a narrow difference within one order of magnitude worldwide and no relationship with GDP. Consequently, the relative importance of major two pathways depended on the contamination extent of PBDEs in house dust, which may be associated with the amount of PBDE products in use. In most countries except for UK and USA, the contribution of house dust ingestion was less important than diet intake in the current and are expected to much more mitigate in the future. However, how fast the effect of regulation will be reflected to house dust and human exposure is necessary to be monitored steadily. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of a Simultaneous Extraction and Cleanup Method for Pyrethroid Pesticides from Indoor House Dust Samples

EPA Science Inventory

An efficient and reliable analytical method was developed for the sensitive and selective quantification of pyrethroid pesticides (PYRs) in house dust samples. The method is based on selective pressurized liquid extraction (SPLE) of the dust-bound PYRs into dichloromethane (DCM) wi...

Pathways of Pb and Mn observed in a 5-year longitudinal investigation in young children and environmental measures from an urban setting.

PubMed

Gulson, Brian; Mizon, Karen; Taylor, Alan; Korsch, Michael; Davis, J Michael; Louie, Honway; Wu, Michael; Gomez, Laura; Antin, Luminita

2014-08-01

We monitored 108 children ≤5 years on a 6-month basis for up to 5 years in a major urban setting. Samples (n ∼ 7000) included blood, urine, handwipes (interior, and after exterior playing), 6-day duplicate diet, drinking water, interior house and day care dust-fall accumulation using petri dishes, exterior dust-fall accumulation, exterior dust sweepings, paint, soil and urban air. The geometric mean blood Pb (PbB) was 2.1 μg/dL and blood Mn (MnB) was 10.0 μg/L. Following a path modelling approach, mixed model analyses for a fully adjusted model showed the strongest associations for PbB were with interior house dust and soil; for MnB there were no significant associations with any predictors. Predictor variables only explained 9% of the variance for Pb and 0.7% for Mn. Relationships between environmental measures and PbB in children are not straightforward; soil and dust sweepings contribute only about 1/5th of the amounts to PbB found in other studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Probing Pre-Supernova Mass Loss With Circumstellar Dust Shells

NASA Astrophysics Data System (ADS)

Fox, Ori; Filippenko, Alex; Skrutskie, Mike; van Dyk, Schuyler; Kelly, Pat

2014-12-01

Late-time (>100 day) mid-infrared (mid-IR) observations of supernovae (SNe) offer a valuable probe of the progenitor system's mass-loss. Already, this technique has been demonstrated with the Type IIn subclass, which often have large, dusty, pre-existing shells formed in pre-SN eruptions. While other SN subclasses are thought of having relatively low density circumstellar environments, a growing number of objects in other subclasses now show evidence for significant pre-SN mass loss and similar mid-IR characteristics. Long after the SN radioactive tail fades, warm dust can stay bright at mid-IR wavelengths due to alternative heating mechanisms, such as shocks. Here we propose a SNAPSHOT survey of a well-studied and high-profile SN sample, extending over a range of subclasses, including both recent and historical events with evidence of a dense CSM and/or dust. This program will (a) discover new SNe with warm dust and (b) monitor the evolution of warm dust in previously detected SNe. Harnessing the success of our previous Spitzer programs, these observations will expand upon that work by probing the similarities in and differences between the subclasses' circumstellar environments, pre-SN mass-loss, and ultimately, the progenitors themselves.

New Medium for Isolation of Bacteria From Cement Kiln Dust with a Potential to Apply in Bio-Concrete

NASA Astrophysics Data System (ADS)

Alshalif, A. F.; Irwan, J. M.; Othman, N.; Al-Gheethi, A.

2018-04-01

The present study aimed to introduce a new isolation medium named kiln dust medium (KDM) for recovering of bacteria from cement kiln dust with high pH (>pH 11) without the need for nutrients additives. The cement kiln dust samples were collected from five different areas of Cement Industries of Malaysia Berhad (CIMA). The bacterial isolates were recovered on KDM by direct plating technique. The chemical components for all collected samples were identified using X-ray fluorescence (XRF). The primary identification for the bacterial isolates indicated that these bacteria belongs to Bacillus spp. Based on the morphological characteristics. The growth curve of the bacterial strains was monitored using the optical density (OD) with 650 nm wavelength, which in role confirmed that all isolated bacteria had the ability to grow successfully in the proposed medium. The ability of the bacterial strains to grow at high pH reflects their potential in the bio-concrete applications (aerated and non-aerated concrete). These findings indicated that the cement kiln dust samples from Cement Industries represent the most appropriate source for bacteria used in the bioconcrete.

Disentangling dust emission mechanisms – a field study

USDA-ARS?s Scientific Manuscript database

Field observations are needed to both develop and test theories on dust emission for use in global modeling systems. The dust emission mechanism (aerodynamic entrainment, saltation bombardment, aggregate disintegration) as well as the amount and particle-size distribution of emitted dust may vary un...

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.

Dusty disc-planet interaction with dust-free simulations

NASA Astrophysics Data System (ADS)

Chen, Jhih-Wei; Lin, Min-Kai

2018-05-01

Protoplanets may be born into dust-rich environments if planetesimals formed through streaming or gravitational instabilities, or if the protoplanetary disc is undergoing mass loss due to disc winds or photoevaporation. Motivated by this possibility, we explore the interaction between low mass planets and dusty protoplanetary discs with focus on disc-planet torques. We implement Lin & Youdin's newly developed, purely hydrodynamic model of dusty gas into the PLUTO code to simulate dusty protoplanetary discs with an embedded planet. We find that for imperfectly coupled dust and high metallicity, e.g. Stokes number 10-3 and dust-to-gas ratio Σd/Σg = 0.5, a `bubble' develops inside the planet's co-orbital region, which introduces unsteadiness in the flow. The resulting disc-planet torques sustain large amplitude oscillations that persists well beyond that in simulations with perfectly coupled dust or low dust-loading, where co-rotation torques are always damped. We show that the desaturation of the co-rotation torques by finite-sized particles is related to potential vorticity generation from the misalignment of dust and gas densities. We briefly discuss possible implications for the orbital evolution of protoplanets in dust-rich discs. We also demonstrate Lin & Youdin's dust-free framework reproduces previous results pertaining to dusty protoplanetary discs, including dust-trapping by pressure bumps, dust settling, and the streaming instability.

Investigating Sensitivity to Saharan Dust in Tropical Cyclone Formation Using Nasa's Adjoint Model

NASA Technical Reports Server (NTRS)

Holdaway, Daniel

2015-01-01

As tropical cyclones develop from easterly waves coming of the coast of Africa they interact with dust from the Sahara desert. There is a long standing debate over whether this dust inhibits or advances the developing storm and how much influence it has. Dust can surround the storm and absorb incoming solar radiation, cooling the air below. As a result an energy source for the system is potentially diminished, inhibiting growth of the storm. Alternatively dust may interact with clouds through micro-physical processes, for example by causing more moisture to condense, potentially increasing the strength. As a result of climate change, concentrations and amount of dust in the atmosphere will likely change. It it is important to properly understand its effect on tropical storm formation. The adjoint of an atmospheric general circulation model provides a very powerful tool for investigating sensitivity to initial conditions. The National Aeronautics and Space Administration (NASA) has recently developed an adjoint version of the Goddard Earth Observing System version 5 (GEOS-5) dynamical core, convection scheme, cloud model and radiation schemes. This is extended so that the interaction between dust and radiation is also accounted for in the adjoint model. This provides a framework for examining the sensitivity to dust in the initial conditions. Specifically the set up allows for an investigation into the extent to which dust affects cyclone strength through absorption of radiation. In this work we investigate the validity of using an adjoint model for examining sensitivity to dust in hurricane formation. We present sensitivity results for a number of systems that developed during the Atlantic hurricane season of 2006. During this period there was a significant outbreak of Saharan dust and it is has been argued that this outbreak was responsible for the relatively calm season. This period was also covered by an extensive observation campaign. It is shown that the adjoint can provide insight into the sensitivity and reveals a relatively low sensitivity to dust compared to, for example, the thermodynamic variables. However a secondary sensitivity though moisture is seen. If dust dries the air it can significantly reduce the cyclone intensity through the moisture.

Investigating sensitivity to Saharan dust in tropical cyclone formation using NASA's adjoint model

NASA Astrophysics Data System (ADS)

Holdaway, Daniel

2015-04-01

As tropical cyclones develop from easterly waves coming off the coast of Africa they interact with dust from the Sahara desert. There is a long standing debate over whether this dust inhibits or advances the developing storm and how much influence it has. Dust can surround the storm and absorb incoming solar radiation, cooling the air below. As a result an energy source for the system is potentially diminished, inhibiting growth of the storm. Alternatively dust may interact with clouds through micro-physical processes, for example by causing more moisture to condense, potentially increasing the strength. As a result of climate change, concentrations and amount of dust in the atmosphere will likely change. It it is important to properly understand its effect on tropical storm formation. The adjoint of an atmospheric general circulation model provides a very powerful tool for investigating sensitivity to initial conditions. The National Aeronautics and Space Administration (NASA) has recently developed an adjoint version of the Goddard Earth Observing System version 5 (GEOS-5) dynamical core, convection scheme, cloud model and radiation schemes. This is extended so that the interaction between dust and radiation is also accounted for in the adjoint model. This provides a framework for examining the sensitivity to dust in the initial conditions. Specifically the set up allows for an investigation into the extent to which dust affects cyclone strength through absorption of radiation. In this work we investigate the validity of using an adjoint model for examining sensitivity to dust in hurricane formation. We present sensitivity results for a number of systems that developed during the Atlantic hurricane season of 2006. During this period there was a significant outbreak of Saharan dust and it is has been argued that this outbreak was responsible for the relatively calm season. This period was also covered by an extensive observation campaign. It is shown that the adjoint can provide insight into the sensitivity and reveals a relatively low sensitivity to dust compared to, for example, the thermodynamic variables. However a secondary sensitivity though moisture is seen. If dust dries the air it can significantly reduce the cyclone intensity through the moisture.

Planetary Dust: Cross-Functional Considerations

NASA Technical Reports Server (NTRS)

Wagner, Sandra

2006-01-01

Apollo astronauts learned first hand how problems with dust impact lunar surface missions. After three days, lunar dust contaminating on EVA suit bearings led to such great difficulty in movement that another EVA would not have been possible. Dust clinging to EVA suits was transported into the Lunar Module. During the return trip to Earth, when microgravity was reestablished, the dust became airborne and floated through the cabin. Crews inhaled the dust and it irritated their eyes. Some mechanical systems aboard the spacecraft were damaged due to dust contamination. Study results obtained by Robotic Martian missions indicate that Martian surface soil is oxidative and reactive. Exposures to the reactive Martian dust will pose an even greater concern to the crew health and the integrity of the mechanical systems. As NASA embarks on planetary surface missions to support its Exploration Vision, the effects of these extraterrestrial dusts must be well understood and systems must be designed to operate reliably and protect the crew in the dusty environments of the Moon and Mars. The AIM Dust Assessment Team was tasked to identify systems that will be affected by the respective dust, how they will be affected, associated risks of dust exposure, requirements that will need to be developed, identified knowledge gaps, and recommended scientific measurements to obtain information needed to develop requirements, and design and manufacture the surface systems that will support crew habitation in the lunar and Martian outposts.

The Vertical Dust Profile over Gale Crater

NASA Astrophysics Data System (ADS)

Guzewich, S.; Newman, C. E.; Smith, M. D.; Moores, J.; Smith, C. L.; Moore, C.; Richardson, M. I.; Kass, D. M.; Kleinboehl, A.; Martin-Torres, F. J.; Zorzano, M. P.; Battalio, J. M.

2017-12-01

Regular joint observations of the atmosphere over Gale Crater from the orbiting Mars Reconnaissance Orbiter/Mars Climate Sounder (MCS) and Mars Science Laboratory (MSL) Curiosity rover allow us to create a coarse, but complete, vertical profile of dust mixing ratio from the surface to the upper atmosphere. We split the atmospheric column into three regions: the planetary boundary layer (PBL) within Gale Crater that is directly sampled by MSL (typically extending from the surface to 2-6 km in height), the region of atmosphere sampled by MCS profiles (typically 25-80 km above the surface), and the region of atmosphere between these two layers. Using atmospheric optical depth measurements from the Rover Environmental Monitoring System (REMS) ultraviolet photodiodes (in conjunction with MSL Mast Camera solar imaging), line-of-sight opacity measurements with the MSL Navigation Cameras (NavCam), and an estimate of the PBL depth from the MarsWRF general circulation model, we can directly calculate the dust mixing ratio within the Gale Crater PBL and then solve for the dust mixing ratio in the middle layer above Gale Crater but below the atmosphere sampled by MCS. Each atmospheric layer has a unique seasonal cycle of dust opacity, with Gale Crater's PBL reaching a maximum in dust mixing ratio near Ls = 270° and a minimum near Ls = 90°. The layer above Gale Crater, however, has a seasonal cycle that closely follows the global opacity cycle and reaches a maximum near Ls = 240° and exhibits a local minimum (associated with the "solsticial pauses") near Ls = 270°. Knowing the complete vertical profile also allows us to determine the frequency of high-altitude dust layers above Gale, and whether such layers truly exhibit the maximum dust mixing ratio within the entire vertical column. We find that 20% of MCS profiles contain an "absolute" high-altitude dust layer, i.e., one in which the dust mixing ratio within the high-altitude dust layer is the maximum dust mixing ratio in the vertical column of atmosphere over Gale Crater.

Dust Removal Technology Demonstration for a Lunar Habitat

NASA Technical Reports Server (NTRS)

Calle, C. I.; Chen, A.; Immer, C. D.; Csonka, M.; Hogue, M. D.; Snyder, S. J.; Rogriquez, M.; Margiotta, D. V.

2010-01-01

We have developed an Electrodynamic Dust Shield (EDS), an active dust mitigation technology with applications to solar panels, thermal radiators, optical systems, visors, seals and connectors. This active technology is capable of removing dust and granular material with diameters as large as several hundred microns. In this paper, we report on the development of three types of EDS systems for NASA's Habitat Demonstration Unit (HDU). A transparent EDS 20 cm in diameter with indium tin oxide electrodes on a 0.1 mm-thick polyethylene terephtalate (PET) film was constructed for viewport dust protection. Two opaque EDS systems with copper electrodes on 0.1 mm-thick Kapton were also built to demonstrate dust removal on the doors of the HDU. A lotus coating that minimizes dust adhesion was added to one of the last two EDS systems to demonstrate the effectiveness of the combined systems.

Temporal and spatial mapping of atmospheric dust opacity and surface albedo on Mars

NASA Technical Reports Server (NTRS)

Lee, S. W.; Clancy, R. T.; Gladstone, G. R.; Martin, T. Z.

1993-01-01

The Mariner 9 and Viking missions provided abundant evidence that eolian processes are active over much of the surface of Mars. Past studies have demonstrated that variations in regional albedo and wind streak patterns are indicative of sediment transport through a region, while thermal inertia data (derived from the Viking Infrared Thermal Mapper (IRTM) datasets) are indicative of the degree of surface mantling by dust deposits. We are making use of the method developed by T. Z. Martin to determine dust opacity from IRTM thermal observations. We have developed a radiative transfer model that allows corrections for the effects of atmospheric dust loading on observations of surface albedo to be made. This approach to determining 'dust-corrected surface albedo' incorporates the atmospheric dust opacity, the single-scattering albedo and particle phase function of atmospheric dust, the bidirectional reflectance of the surface, and accounts for variable lighting and viewing geometry.

Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Amato, F.; Karanasiou, A.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.

2012-08-01

Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban Environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter <2.5 μm) resolved Particle Induced X-ray Emission (PIXE) measurements. In the Marie Curie FP7-EU framework of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies), the unique approach used is the simultaneous PIXE measurements at two monitoring sites: urban background (UB) and a street canyon traffic road site (RS). Elements related to primary non exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (secondary sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non exhaust brake dust (Fe-Cu) - 7%), and three types industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%). The validity of the PMF solution of the PIXE data is supported by strong correlations with external single particle mass spectrometry measurements. Beside apportioning the aerosol sources, some important air quality related conclusions can be drawn about the PM2.5 fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2) by contrast, local industrial aerosol plumes associated with shipping oil combustion and smelters activities have a higher impact on the more ventilated UB site; (3) a unique source of Pb-Cl (associated with industrial combustion emissions) is found a to be the major (82%) source of Cl in the urban agglomerate; (4) PM2.5 traffic brake dust (Fe-Cu) is mainly primarily emitted and not resuspended, whereas PM2.5 urban crustal dust (Ca) is found mainly resuspended by both traffic vortex and sea breeze; (5) urban dust (Ca) is found the aerosol source most affected by land wetness, reduced by a factor of eight during rainy days and suggesting that wet roads may be a solution for reducing dust concentrations in road sites, far more effective than street sweeping activities.

Identifying Dust Sources by Positive Matrix Factorization (PMF)

NASA Astrophysics Data System (ADS)

Engelbrecht, Johann P.

2010-05-01

This presentation is on the source attribution by Positive Matrix Factorization (PMF) of aerosol samples collected in Iraq, a major source of mineral dust in the Middle East. Globally transported mineral dust from North Africa, the Middle East, China, and elsewhere are routinely being sampled at high elevation monitoring sites such as those on the Canary Islands and Hawaii, and many ambient monitoring sites worldwide. Chemical results of these filter samples reflect differences in sources impacting at each site, further complicated by the regional geomorphology and meteorology. Trace elements, isotopes, elemental ratios, and mineralogy are generally being used to pinpoint geological source regions of natural and anthropogenic dusts. A receptor site is seldom impacted by only one source at a time. Dust palls are continually being modified by added dust from soils across which they migrate, also by particle segregation in the dust plume, and precipitation of the coarser particles. The result is that dust is a mixture, with contributions from different sources, each with a different chemical and mineralogical signature. PMF is a non-negative factorization procedure that produces only positive factor scores and loadings, in contrast to classical factor analysis (FA) and Principal Components Analysis (PCA). PMF enables us to resolve factors (chemical signatures) for source types contributing to the ambient chemical data set, and also models the source-type contributions to individual ambient samples. The latter can often be related to specific source regions. PMF was applied separately to two ambient data sets collected in Iraq in 2006, the one on Teflon membrane filters and the other on quartz fiber. Each of the filter types were previously analyzed for different chemical species: Teflon membrane for elements, by XRF and ICP-MS, while quartz fiber filters were analyzed for ions and carbon. [Engelbrecht et al. 2009] A set of 392 Teflon filter samples analyzed for 25 elemental species was modeled by PMF. A five factor solution identified three soil factors, a silicate soil, limestone soil, and a gypsum soil, as well as a salt factor and an anthropogenic metal factor. Similarly, a set of 362 quartz filter samples analyzed for 10 selected chemical species was modeled by PMF. A five factor solution provided a limestone-gypsum soil, diesel combustion, secondary ammonium sulfate, salt and agricultural-burnpit combustion source type. Examples of time series plots of PMF factor contributions for each of six sampling sites (Balad, Baghdad, Tallil, Tikrit, Taji, and Al Asad) will be discussed. Engelbrecht , J. P., McDonald, E. V., Gillies, J. A., Jayanty, R. K. M., Casuccio, G., and Gertler, A. W., 2009, Characterizing mineral dusts and other aerosols from the Middle East - Part 1: Ambient sampling: Inhalation Toxicology, v. 21, p. 297-326.

Proof of concept demonstration of novel technologies for lunar spacesuit dust mitigation

NASA Astrophysics Data System (ADS)

Manyapu, Kavya K.; De Leon, Pablo; Peltz, Leora; Gaier, James R.; Waters, Deborah

2017-08-01

A recent report by NASA identified dust/particulate mitigation techniques as a highly relevant study for future long-term planetary exploration missions (NASA, 2015). The deleterious effects of lunar dust on spacesuits discovered during the Apollo missions has compelled NASA to identify dust mitigation as a critical path for potential future lunar, asteroid and Mars missions. The complexity of spacesuit design has however constrained integrating existing dust cleaning technologies, formerly demonstrated on rigid surfaces, into the spacesuit system. Accordingly, this research is investigating novel methods to integrate dust mitigation technologies for use on spacesuits. We examine utilizing a novel combination of active and passive technologies integrated into the spacesuit outerlayer to alleviate dust contamination. Leveraging two specific technologies, the Electrodynamics Dust Shield (EDS) active technology and Work Function Matching Coating (WFM) passive technology, developed by NASA for rigid surfaces, we apply new high performance materials such as the Carbon Nanotube (CNT) flexible fibers to develop a spacesuit-integrated dust cleaning system. Through experiments conducted using JSC-1A lunar dust simulant on coupons made of spacesuit outerlayer material, feasibility of integrating the proposed dust cleaning system and its performance were assessed. Results from these preliminary experiments show that the integrated dust cleaning system is capable of removing 80-95% of dust from the spacesuit material demonstrating proof of concept. This paper describes the techniques and results from the experiments. Future challenges of implementing the proposed approach into fight suits are identified.

Regional and transported aerosols during DRAGON-Japan experiment

NASA Astrophysics Data System (ADS)

Sano, I.; Holben, B. N.; Mukai, S.; Nakata, M.; Nakaguchi, Y.; Sugimoto, N.; Hatakeyama, S.; Nishizawa, T.; Takamura, T.; Takemura, T.; Yonemitsu, M.; Fujito, T.; Schafer, J.; Eck, T. F.; Sorokin, M.; Kenny, P.; Goto, M.; Hiraki, T.; Iguchi, N.; Kouzai, K.; KUJI, M.; Muramatsu, K.; Okada, Y.; Sadanaga, Y.; Tohno, S.; Toyazaki, Y.; Yamamoto, K.

2013-12-01

Aerosol properties over Japan have been monitored by AERONET sun / sky photometers since 2000. These measurements provides us with long term information of local aerosols, which are influenced by transported aerosols, such as Asian dusts or anthropogenic pollutants due to rapid increasing of energy consumption in Asian countries. A new aerosol monitoring experiment, Distributed Regional Aerosol Gridded Observation Networks (DRAGON) - Japan is operated in spring of 2012. The main instrument of DRAGON network is AERONET sun/sky radiometers. Some of them are sparsely set along the Japanese coast and some others make a dense network in Osaka, which is the second-largest city in Japan and famous for manufacturing town. Several 2ch NIES-LIDAR systems are also co-located with AERONET instrument to monitor Asian dusts throughout the campaign. The objects of Dragon-Japan are to characterize local aerosols as well as transported ones from the continent of China, and to acquire the detailed aerosol information for validating satellite data with high resolved spatial scale. This work presents the comprehensive results of aerosol properties with respect to regional- and/or transported- scale during DRAGON-Japan experiments.

An electrified dust storm over the Negev desert, Israel

NASA Astrophysics Data System (ADS)

Yair, Y.; Price, C. G.; Yaniv, R.; Katz, S.

2015-12-01

We report on atmospheric electrical measurements conducted at the Wise Observatory in Mitzpe-Ramon, Israel (30035'N, 34045'E) during a massive dust storm that occurred over the Eastern Mediterranean region on 10-11 February 2015. The event transported Saharan dust from Egypt and the Sinai Peninsula in advance of the warm front of a Cyprus low pressure system. Satellite images show the dust plume covering the Negev desert and Southern Israel and moving north. The concentrations of PM10 particles measured by the air-quality monitoring network of the Israeli Ministry of the Environment in Beer-Sheba reached values > 450 μg m-3 and AOT from the AERONET station in Sde-Boker was 1.5 on the 10th. The gradual intensification of the event reached peak values on February 11th of over 1200 μg m-3 and AOT of 1.8. This was the most severe dust event in a decade. Continuous measurements of the fair weather vertical electric field (Ez) and vertical current density (Jz) were conducted with 1 minute temporal resolution. Meteorological data was also recorded at the site. As the dust was advected over the observation site, we noted very large fluctuations in the electrical parameters. Since the onset of the dust storm, the Ez values changed between +1000 and +8000 V m-1 while the Jz fluctuated between -10 pA m2 and +20 pA m2, both on time-scales of a few minutes. These values are a significant departures from the mean fair-weather values measured at the site, which are -~200 V m-1 and ~2 pA m2. The disturbed episodes lasted for several hours on the 10th and 11th and coincided with local meteorological conditions related to the wind direction, which carried large amounts of dust particles. We interpret the rapid changes as caused by the transport of electrically charged dust. Calculation of the total electrical charge during the dust storm will be presented.

The variation of characteristics and formation mechanisms of aerosols in dust, haze, and clear days in Beijing

NASA Astrophysics Data System (ADS)

Wang, Ying; Zhuang, Guoshun; Sun, Yele; An, Zhisheng

A 4-year campaign from 2001 to 2004 monitoring PM 2.5 and TSP in the spring season in urban Beijing, China was performed to study the variation of characteristics and the different formation mechanisms of aerosols in dust, haze, and clear days. A total of 315 aerosol samples were collected and used in this study. The aerosols were more basic in dust days and more acidic in haze days. The ions presented in the order of SO42->Ca 2+≫ NO3->Cl -> NH4+>Na + in dust days, and of SO42-> NO3-> NH4+≫Cl ->Ca 2+>K + in haze days. Ions has been classified into three groups, "Na +, Mg 2+, Ca 2+", "K +, SO42-, Cl -", and " NO3-, NH4+", representing crust, pollution-crust, and pollution species, respectively. Crust and pollution ions were the main ion fractions in dust and haze days, respectively. The variation of Ca 2+/Al showed that the increase of dust in dust and haze days was from soil and construction, respectively. "CaCO 3, CaSO 4, and (NH 4) 2SO 4" and "(NH 4) 2SO 4, NH 4NO 3, and Ca(NO 3) 2" were the major species in dust and haze days, respectively. The formation of CaSO 4 on airborne soil particles and the formation of (NH 4) 2SO 4 and NH 4NO 3 were the predominant pathways of sulfate and nitrate formations in dust and haze days, respectively. Sulfate might be mainly formed through heterogeneous reactions in the aqueous surface layer on the pre-existing particles, while nitrate mainly through homogeneous gas-phase reactions in the spring season in Beijing. The formation of sulfate and nitrate was accelerated in dust and haze days.

The Impacts of Dust Storm Particles on Human Lung Cells - an Analysis at the Single Cell Level

NASA Astrophysics Data System (ADS)

Ardon-Dryer, K.; Mock, C.; Reyes, J.; Lahav, G.

2017-12-01

Aerosols particles (Natural and anthropogenic) are a key component of our atmosphere, their presence defines air quality levels and they can affect our health. Small particles penetrate into our lungs and this exposure can cause our lung cells to stress and in some cases leads to the death of the cells and to inflammation. During dust storm events there is an increase in particle concentration, many of them are breathable particles that can penetrate deep into our lungs. Exposure to dust particles can lead to respiratory problems, particularly for people with asthma. Therefore, during and after a dust storm event the number of people who are hospitalized with inflammation and respiratory problems increase. However, the exact mechanism that causes these health problems is still unclear. In this project, we are investigating the impacts that dust storm particles from different sources and of different concentrations (doses) have on human lung cells, performing a new and unique analysis at the single cell level. To accomplish this, each individual lung cell is continuously tracked after being exposed to dust particles. We monitor the behavior of the cell over time, identify the cells time of death and type of death (e.g. cell explosion). With this analysis, we can quantify cell death as a function of dust concertation (doses); to our surprise, an increase in cells death was not observed only as a function of an increase of dust concertation. In addition, we noticed that the way particles come in contact with cells, by sticking to or being engulfed by, and the interaction duration has an effect; cells that interact with dust particles for a longer period died earlier compared to cells with a shorter interaction period. These findings will help us to better understand the health related consequences of exposure to dust storm events and serve as a baseline for when evaluating other aerosol.

Synoptic conditions favouring the occurrence of dust transport from Africa toward Sardinia Island.

NASA Astrophysics Data System (ADS)

Canu, Annalisa; Pellizzaro, Grazia; Pintus, Gabriella; Duce, Pierpaolo

2016-04-01

Dust events that reach Italy have usually origin in the Sahara and Sahel regions (north-western part of Africa), which represent the dust sources nearest to Italy. In those regions the dust-lifting activity occurs in a remarkable way. Every dust event is different from the others; in fact dust transport and dust concentration in the air can vary remarkably depending on the synoptic situation. In Sardinia, dust events are more frequent in the May-November period, but they can also take place in the December-April period. The main aim of this work was to describe dust outbreaks in Sardinia and to identify the main meteorological scenarios that originate the transport of dust towards the central and western Mediterranean Basin. The evaluation of the geographical dispersion of Saharan dust was performed by using MODIS satellite data and Meteosat imagery combined with SKIRON forecasting model. The origin and the trajectory of the dust carried by winds towards Italy were inferred by the NOAA HYSPLIT model (Hybrid Single Particle Lagrangian Integrated Trajectory Model). In addition, PM10 (particulate matter with a diameter of less than 10 μm) and meteorological data registered by the ARPAS (Regional Environmental Protection Agency of Sardinia) monitoring stations were used to highlight the arrival of African air masses in Sardinia. The study was carried out during the 2014. A total of five events occurred during the year (two in spring and three in autumn) were analyzed. The origin of air masses loaded with dust from North Africa was confirmed by satellite imagery and 3-days air mass backward trajectories calculated by the NOAA HYSPLIT model. The analysis of the PM10 daily pattern registered at northern and southern Sardinia sites showed a rising of values during the dust event. The arrival of air masses from Africa caused the daily mean air temperature to rise whereas relative humidity values decreased. Finally, the results showed that all the event analyzed were characterized by a low-pressure system over the Iberian Peninsula that extended towards Morocco and by the associated high-pressure system over the North-East Africa (Algeria, Tunisia and Libya) and Sicily. This synoptic structure (low pressure over North-Western Africa) forced the dusty air masses towards the Mediterranean basin, favouring the transport of African air masses towards the Sardinia island.

The physics of wind-blown sand and dust.

PubMed

Kok, Jasper F; Parteli, Eric J R; Michaels, Timothy I; Karam, Diana Bou

2012-10-01

The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This paper presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

The physics of wind-blown sand and dust

NASA Astrophysics Data System (ADS)

Kok, Jasper F.; Parteli, Eric J. R.; Michaels, Timothy I.; Karam, Diana Bou

2012-10-01

The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This paper presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

Nighttime Infrared radiative cooling and opacity inferred by REMS Ground Temperature Sensor Measurements

NASA Astrophysics Data System (ADS)

Martín-Torres, Javier; Paz Zorzano, María; Pla-García, Jorge; Rafkin, Scot; Lepinette, Alain; Sebastián, Eduardo; Gómez-Elvira, Javier; REMS Team

2013-04-01

Due to the low density of the Martian atmosphere, the temperature of the surface is controlled primarily by solar heating, and infrared cooling to the atmosphere and space, rather than heat exchange with the atmosphere. In the absence of solar radiation the infrared (IR) cooling, and then the nighttime surface temperatures, are directly controlled by soil termal inertia and atmospheric optical thickness (τ) at infrared wavelengths. Under non-wind conditions, and assuming no processes involving latent heat changes in the surface, for a particular site where the rover stands the main parameter controlling the IR cooling will be τ. The minimal ground temperature values at a fixed position may thus be used to detect local variations in the total dust/aerosols/cloud tickness. The Ground Temperature Sensor (GTS) and Air Temperature Sensor (ATS) in the Rover Environmental Monitoring Station (REMS) on board the Mars Science Laboratory (MSL) Curiosity rover provides hourly ground and air temperature measurements respectively. During the first 100 sols of operation of the rover, within the area of low thermal inertia, the minimal nightime ground temperatures reached values between 180 K and 190 K. For this season the expected frost point temperature is 200 K. Variations of up to 10 K have been observed associated with dust loading at Gale at the onset of the dust season. We will use these measurements together with line-by-line radiative transfer simulations using the Full Transfer By Optimized LINe-by-line (FUTBOLIN) code [Martín-Torres and Mlynczak, 2005] to estimate the IR atmospheric opacity and then dust/cloud coverage over the rover during the course of the MSL mission. Monitoring the dust loading and IR nightime cooling evolution during the dust season will allow for a better understanding of the influence of the atmosphere on the ground temperature and provide ground truth to models and orbiter measurements. References Martín-Torres, F. J. and M. G. Mlynczak, Application of FUTBOLIN (FUll Transfer By Ordinary Line-by-Line) to the analysis of the solar system and extrasolar planetary atmospheres, Bulletin of the American Astronomical Society, Vol. 37, p.1566, 2005

Comparison between light scattering and gravimetric samplers for PM10 mass concentration in poultry and pig houses

NASA Astrophysics Data System (ADS)

Cambra-López, María; Winkel, Albert; Mosquera, Julio; Ogink, Nico W. M.; Aarnink, André J. A.

2015-06-01

The objective of this study was to compare co-located real-time light scattering devices and equivalent gravimetric samplers in poultry and pig houses for PM10 mass concentration, and to develop animal-specific calibration factors for light scattering samplers. These results will contribute to evaluate the comparability of different sampling instruments for PM10 concentrations. Paired DustTrak light scattering device (DustTrak aerosol monitor, TSI, U.S.) and PM10 gravimetric cyclone sampler were used for measuring PM10 mass concentrations during 24 h periods (from noon to noon) inside animal houses. Sampling was conducted in 32 animal houses in the Netherlands, including broilers, broiler breeders, layers in floor and in aviary system, turkeys, piglets, growing-finishing pigs in traditional and low emission housing with dry and liquid feed, and sows in individual and group housing. A total of 119 pairs of 24 h measurements (55 for poultry and 64 for pigs) were recorded and analyzed using linear regression analysis. Deviations between samplers were calculated and discussed. In poultry, cyclone sampler and DustTrak data fitted well to a linear regression, with a regression coefficient equal to 0.41, an intercept of 0.16 mg m-3 and a correlation coefficient of 0.91 (excluding turkeys). Results in turkeys showed a regression coefficient equal to 1.1 (P = 0.49), an intercept of 0.06 mg m-3 (P < 0.0001) and a correlation coefficient of 0.98. In pigs, we found a regression coefficient equal to 0.61, an intercept of 0.05 mg m-3 and a correlation coefficient of 0.84. Measured PM10 concentrations using DustTraks were clearly underestimated (approx. by a factor 2) in both poultry and pig housing systems compared with cyclone pre-separators. Absolute, relative, and random deviations increased with concentration. DustTrak light scattering devices should be self-calibrated to investigate PM10 mass concentrations accurately in animal houses. We recommend linear regression equations as animal-specific calibration factors for DustTraks instead of manufacturer calibration factors, especially in heavily dusty environments such as animal houses.

Monitoring Atmospheric Dust Opacity at High Latitudes on Mars by Imaging Spectroscopy

NASA Astrophysics Data System (ADS)

Doute, S.; Vincendon, M.; Langevin, Y.; Spiga, A.; Bibring, J.; OMEGA Team

2010-12-01

Micrometer sized mineral particles drifting over Mars surface greatly influence both solar and thermal radiative fluxes in the atmosphere, thus its energy balance and its global circulation. Furthermore any kind of remotely sensed data in the optical domain includes their strong, spatially varying, often annoying contributions. Monitoring the particles as well as identifying the sources and the sinks in relation with surface activity is of paramount importance. Since 2004 and 2006 respectively, the imaging spectrometers OMEGA@MEX and CRISM@MRO perform nadir-looking and EPF observations in the VIS and the NIR for the study of the surface and atmosphere alike. We propose an original method to retrieve the optical depth τ dust of the Martian dust over the targeted scenes at a reference wavelength of one micron. Our method works even if the underlying surface is completely made of minerals (low contrast between surface and atmospheric dust) while being observed at a fixed geometry. Nevertheless it provides the maximum of information when applied to spectra acquired over the same area at different emergence angles. The method is based on a parametrization of the radiative coupling between particles and gas that determines, with local altimetry and the meteorological situation, the absorption band depth of gaseous CO2. The coupling depends on (i) the acquisition geometry (ii) the type, abundance and vertical distribution of particles (iii) the surface albedo As. For each spectro-pixel of an image, comparison of band depths estimated on the one hand from the observed spectrum and on the other hand from a calculated transmission spectrum through the atmospheric gases alone, one can build a precious new observable that directly depends on τ dust. Combining the latter with the radiance factor in the continuum, we evaluate after LUT inversion τ dust and As. After validation on test images, we have applied the present method - associated with a complementary approach proposed by [1] - in order to map dust abundance at high southern latitudes from early to late spring of MY 27 and 28. For that purpose we use a time series of OMEGA images for global coverage associated with a limited number of more spatially focused CRISM observations to determine the scale height of dust vertical distribution. As a result, we obtain de-trended and extended maps that are corrected for changes of optical depth due to varying atmospheric height because of topography. They clearly show dust activity within and around the area covered by the CO2 seasonal deposits. Atmospheric mineral particles are clearly depleted above the latter compared to the surroundings, even if occasional incursions of dusty clouds can occur. We note sudden, strong and spatially localized enhancements of dust opacity that can be traced as they migrate before disappearance. [1] Vincendon et al. JGR 2008

Aeolian system dynamics derived from thermal infrared data

NASA Astrophysics Data System (ADS)

Scheidt, Stephen Paul

Thermal infrared (TIR) remote-sensing and field-based observations were used to study aeolian systems, specifically sand transport pathways, dust emission sources and Saharan atmospheric dust. A method was developed for generating seamless and radiometrically accurate mosaics of thermal infrared data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. Using a combination of high resolution thermal emission spectroscopy results of sand samples and mosaic satellite data, surface emissivity was derived to map surface composition, which led to improvement in the understanding of sand accumulation in the Gran Desierto of northern Sonora, Mexico. These methods were also used to map sand transport pathways in the Sahara Desert, where the interaction between sand saltation and dust emission sources was explored. The characteristics and dynamics of dust sources were studied at White Sands, NM and in the Sahara Desert. At White Sands, an application was developed for studying the response of dust sources to surface soil moisture based on the relationship between soil moisture, apparent thermal inertia and the erosion potential of dust sources. The dynamics of dust sources and the interaction with sand transport pathways were also studied, focusing on the Bodele Depression of Chad and large dust sources in Mali and Mauritania. A dust detection algorithm was developed using ASTER data, and the spectral emissivity of observed atmospheric dust was related to the dust source area in the Sahara. At the Atmospheric Observatory (IZO) in Tenerife, Spain where direct measurement of the Saharan Air Layer could be made, the cycle of dust events occurring in July 2009 were examined. From the observation tower at the IZO, measurements of emitted longwave atmospheric radiance in the TIR wavelength region were made using a Forward Looking Infrared Radiometer (FLIR) handheld camera. The use of the FLIR to study atmospheric dust from the Saharan is a new application. Supporting data from AERONET and other orbital data enabled study of net radiative forcing.

Remote sensing of desert dust aerosols over the Sahel : potential use for health impact studies

NASA Astrophysics Data System (ADS)

Deroubaix, A. D.; Martiny, N. M.; Chiapello, I. C.; Marticorena, B. M.

2012-04-01

Since the end of the 70's, remote sensing monitors the desert dust aerosols due to their absorption and scattering properties and allows to make long time series which are necessary for air quality or health impact studies. In the Sahel, a huge health problem is the Meningitis Meningococcal (MM) epidemics that occur during the dry season : the dust has been suspected to be crucial to understand their onsets and dynamics. The Aerosol absorption Index (AI) is a semi-quantitative index derived from TOMS and OMI observations in the UV available at a spatial resolution of 1° (1979-2005) and 0.25° (2005-today) respectively. The comparison of the OMI-AI and AERONET Aerosol Optical thickness (AOT) shows a good agreement at a daily time-step (correlation ~0.7). The comparison of the OMI-AI with the Particle Matter (PM) measurement of the Sahelian Dust Transect is lower (~0.4) at a daily time-step but it increases at a weekly time-step (~0.6). The OMI-AI reproduces the dust seasonal cycle over the Sahel and we conclude that the OMI-AI product at a 0.25° spatial resolution is suitable for health impact studies, especially at a weekly epidemiological time-step. Despite the AI is sensitive to the aerosol altitude, it provides a daily spatial information on dust. A preliminary investigation analysis of the link between weekly OMI AI and weekly WHO epidemiological data sets is presented in Mali and Niger, showing a good agreement between the AI and the onset of the MM epidemics with a constant lag (between 1 and 2 week). The next of this study is to analyse a deeper AI time series constituted by TOMS and OMI data sets. Based on the weekly ratios PM/AI at 2 stations of the Sahelian Dust Transect, a spatialized proxy for PM from the AI has been developed. The AI as a proxy for PM and other climate variables such as Temperature (T°), Relative Humidity (RH%) and the wind (intensity and direction) could then be used to analyze the link between those variables and the MM epidemics in the most concerned countries in Western Africa, which would be an important step towards a forecasting tool for the epidemics risks in Western Africa.

An automated and integrated framework for dust storm detection based on ogc web processing services

NASA Astrophysics Data System (ADS)

Xiao, F.; Shea, G. Y. K.; Wong, M. S.; Campbell, J.

2014-11-01

Dust storms are known to have adverse effects on public health. Atmospheric dust loading is also one of the major uncertainties in global climatic modelling as it is known to have a significant impact on the radiation budget and atmospheric stability. The complexity of building scientific dust storm models is coupled with the scientific computation advancement, ongoing computing platform development, and the development of heterogeneous Earth Observation (EO) networks. It is a challenging task to develop an integrated and automated scheme for dust storm detection that combines Geo-Processing frameworks, scientific models and EO data together to enable the dust storm detection and tracking processes in a dynamic and timely manner. This study develops an automated and integrated framework for dust storm detection and tracking based on the Web Processing Services (WPS) initiated by Open Geospatial Consortium (OGC). The presented WPS framework consists of EO data retrieval components, dust storm detecting and tracking component, and service chain orchestration engine. The EO data processing component is implemented based on OPeNDAP standard. The dust storm detecting and tracking component combines three earth scientific models, which are SBDART model (for computing aerosol optical depth (AOT) of dust particles), WRF model (for simulating meteorological parameters) and HYSPLIT model (for simulating the dust storm transport processes). The service chain orchestration engine is implemented based on Business Process Execution Language for Web Service (BPEL4WS) using open-source software. The output results, including horizontal and vertical AOT distribution of dust particles as well as their transport paths, were represented using KML/XML and displayed in Google Earth. A serious dust storm, which occurred over East Asia from 26 to 28 Apr 2012, is used to test the applicability of the proposed WPS framework. Our aim here is to solve a specific instance of a complex EO data and scientific model integration problem by using a framework and scientific workflow approach together. The experimental result shows that this newly automated and integrated framework can be used to give advance near real-time warning of dust storms, for both environmental authorities and public. The methods presented in this paper might be also generalized to other types of Earth system models, leading to improved ease of use and flexibility.

77 FR 37441 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Diesel...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-21

... dust and explosive methane gas are present. Diesel equipment operating in underground coal mines also..., such as cabs or canopies, methane monitors, brakes and lights. Sampling of diesel exhaust emissions is...

PORTABLE TECHNOLOGIES FOR MEASURING LEADING IN DUST

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) Environmental Technology Verification (ETV) program evaluates the performance of innovative air, water, pollution prevention and monitoring technologies that have the potential to improve human health and the environment. This techn...

CSM interaction and dust formation in SN 2010jl .

NASA Astrophysics Data System (ADS)

Krafton, K.; Clayton, G. C.

The origin of dust in galaxies >1 Gyr old has remained an unsolved mystery for over a decade. One proposed solution is dust produced by core collapse supernovae (CCSNe). Theorists have shown that 0.1-1 M⊙ of dust must be produced per supernova for this to work as an explanation for the dust in young galaxies. SN 1987A has produced ˜1 M⊙ of dust since its detonation. However, most supernovae have been found to only produce 10-4 - 10-2 M⊙ of dust. The energetic type IIn SN 2010jl is located in UGC 5189, in a dense shell of CSM. As dust condenses in the SN ejecta, we see, (1) a sudden decrease in continuum brightness in the visible due to increased dust extinction, (2) the development of an infrared excess in the SN light curve arising from dust grains absorbing high-energy photons and re-emitting them in the infrared, and (3) the development of asymmetric, blue-shifted emission-line profiles, caused by dust forming in the ejecta, and preferentially extinguishing redshifted emission. A dense circumstellar material (CSM) may increase the dust production by supernovae. We observe signs of strong interaction between the SN ejecta and a dense CSM in SN 2010jl. SN 2010jl has been a source of much debate in the CCSN community, particularly over when and how much dust it formed. The light curve shows strong signs of dust formation after 260 days. Arguments over these subjects have been based on the evolution of the light curve and spectra. We present new optical and IR photometry, as well as optical spectroscopy, of SN 2010jl over 2000 days. We estimate dust masses using the DAMOCLES and MOCASSIN radiative transfer codes.

The Evolution of Dust in the Multiphase Interstellar Medium

NASA Technical Reports Server (NTRS)

Oliversen, Ronald J. (Technical Monitor); Slavin, Jonathan

2003-01-01

Interstellar dust has a profound effect on the structure and evolution of the interstellar medium (ISM) and on the processes by which stars form from it. Dust obscures regions of star formation from view, and the uncertain quantities of elements in dust makes it difficult to measure accurately the abundances of the elements in low density regions. Despite the central importance of dust in astrophysics, we cannot answer some of the most basic questions about it: Why is it that most of the refractory elements are in dust grains? What determines the sizes of interstellar grains? It has been the goal of our proposed theoretical investigations to address these questions by studying the destruction of interstellar grains, and to develop observational diagnostics that can test the models we develop.

Fine dust emissions in sandy and silty agricultural soils

USDA-ARS?s Scientific Manuscript database

Dust emissions from strong winds are common in arid and semi-arid regions and occur under both natural and managed land systems. A portable field wind tunnel has been developed to allow measurements of dust emissions from soil surfaces to test the premise that dust concentrations are highly correlat...

Demolition and removal of radioactively contaminated concrete soil: Aerosol control and monitoring

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

Newton, G.J.; Hoover, M.D.; Grace, A.C. III

1995-12-01

From 1963 to 1985, two concrete-lined ponds were used to reduce the volume of radioactive liquids from the Institute`s research programs. Following withdrawal of the {open_quotes}hot ponds{close_quotes} from active use, the residual sludges and plastic liners of the ponds were removed and shipped to a radioactive waste disposal site. From 1987 to 1994, the concrete structures remained undisturbed pending environmental restoration on the site. Restoration began in 1994 and was completed in 1995. Restoration involved mechanical breakup and removal of the concrete structures and removal of areas of contaminated soils from the site. This report describes the design and resultsmore » of the aerosol control and monitoring program that was conducted to ensure protection of workers and the environment during the restoration process. The aerosol control and monitoring strategy developed for remediation of the ITRI hot ponds was successful both in preventing dispersion of radioactive dusts and in demonstrating that exposures of workers and offsite releases were within statutory limits.« less

High Resolution BPM for Linear Colliders

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

Simon, C.; Chel, S.; Luong, M.

2006-11-20

A high resolution Beam Position Monitor (BPM) is necessary for the beam-based alignment systems of high energy and low emittance electron linacs. Such a monitor is developed in the framework of the European CARE/SRF programme, in a close collaboration between DESY and CEA/DSM/DAPNIA. This monitor is a radiofrequency re-entrant cavity, which can be used either at room or cryogenic temperature, in an environment where dust particle contamination has to be avoided, such as superconducting cavities in a cryomodule. A first prototype of a re-entrant BPM has already delivered measurements at 2K. inside the first cryomodule (ACC1) on the TESLA Testmore » Facility 2 (TTF2). The performances of this BPM are analyzed both experimentally and theoretically, and the limitations of this existing system clearly identified. A new cavity and new electronics have been designed in order to improve the position resolution down to 1 {mu}m and the damping time down to 10 ns.« less

Monitoring of Saharan dust fallout on Crete and its contribution to soil formation

NASA Astrophysics Data System (ADS)

Nihlén, Tomas; Mattsson, Jan O.; Rapp, Anders; Gagaoudaki, Chrisoula; Kornaros, Georges; Papageorgiou, John

1995-07-01

A series of 6 dust traps was established in 1988 distributed over the island of Crete (Greece). Eolian dust has been collected in the traps each year and in each season during the 4years of investigation which is still going on. The mean deposition rate for the 6 stations and 4years was calculated as 21.3g m2yr1. Using the highest and lowest values, the deposition can be extrapolated to 6.6-21.4mm for 1000years, which is in agreement with other researchers' findings. The trapped dust shows a homogeneous grain-size distribution. Its mineralogy is similar to what characterizes soil samples from Psiloritis on Crete and source areas in southern Tunisia. In the fine fraction of the soil (particles < 10µm), the contents of the clay mineral kaolinite and of quartz are high. In addition, the oxygen isotope composition of the 3 types of substrate is similar but differs from the weathering products of the limestone bedrock. Statistics of dust episodes covering the period c. 1955-1990 from 10 meteorological stations in Greece revealed that long-distance transport of dust in combination with winds from a southerly sector is common in the Aegean area during spring.

Personal exposure of dairy workers to dust, endotoxin, muramic acid, ergosterol, and ammonia on large-scale dairies in the high plains Western United States.

PubMed

Davidson, Margaret E; Schaeffer, Joshua; Clark, Maggie L; Magzamen, Sheryl; Brooks, Elizabeth J; Keefe, Thomas J; Bradford, Mary; Roman-Muniz, Noa; Mehaffy, John; Dooley, Gregory; Poole, Jill A; Mitloehner, Frank M; Reed, Sue; Schenker, Marc B; Reynolds, Stephen J

2018-03-01

Dairy workers experience a high degree of bioaerosol exposure, composed of an array of biological and chemical constituents, which have been tied to adverse health effects. A better understanding of the variation in the magnitude and composition of exposures by task is needed to inform worker protection strategies. To characterize the levels and types of exposures, 115 dairy workers grouped into three task categories on nine farms in the high plains Western United States underwent personal monitoring for inhalable dust, endotoxin, 3-hydroxy fatty acids (3-OHFA), muramic acid, ergosterol, and ammonia through one work shift. Eighty-nine percent of dairy workers were exposed to endotoxin at concentrations exceeding the recommended exposure guidelines (adjusted for a long work shift). The proportion of workers with exposures exceeding recommended guidelines was lower for inhalable dust (12%), and ammonia (1%). Ergosterol exposures were only measurable on 28% of samples, primarily among medical workers and feed handlers. Milking parlor workers were exposed to significantly higher inhalable dust, endotoxin, 3-OHFA, ammonia, and muramic acid concentrations compared to workers performing other tasks. Development of large modern dairies has successfully made progress in reducing worker exposures and lung disease prevalence. However, exposure to endotoxin, dust, and ammonia continues to present a significant risk to worker health on North American dairies, especially for workers in milking parlors. This study was among the first to concurrently evaluate occupational exposure to assayable endotoxin (lipid A), 3-hydroxy fatty acids or 3-OHFA (a chemical measure of cell bound and noncell-bound endotoxins), muramic acid, ergosterol, and ammonia among workers on Western U.S. dairies. There remains a need for cost-effective, culturally acceptable intervention strategies integrated in OHS Risk Management and production systems to further optimize worker health and farm productivity.

Assessment of rangeland ecosystem conditions, Salt Creek watershed and Dugout Ranch, southeastern Utah

USGS Publications Warehouse

Bowker, M.A.; Miller, M.E.; Belote, R.T.

2012-01-01

Increasingly, dry rangelands are being valued for multiple services beyond their traditional value as a forage production system. Additional ecosystem services include the potential to store carbon in the soil and plant biomass. In addition, dust emissions from rangelands might be considered an ecosystem detriment, the opposite of an ecosystem service. Dust emitted may have far-reaching impacts, for example, reduction of local air quality, as well as altering regional water supplies through effects on snowpack. Using an extensive rangeland monitoring dataset in the greater Canyonlands region (Utah, USA), we developed a method to estimate indices of the provisioning of three ecosystem services (forage production, dust retention, C storage) and one ecosystem property (nativeness), taking into account both ecosystem type and alternative states within that ecosystem type. We also integrated these four indices into a multifunctionality index. Comparing the currently ungrazed Canyonlands National Park watersheds to the adjacent Dugout Ranch pastures, we found clearly higher multifunctionality was attained in the Park, and that this was primarily driven by greater C-storage and better dust retention. It is unlikely to maximize all benefits and minimize all detriments at the same time. Some goods and services may have synergistic interactions; for example, managing for carbon storage will increase plant and biocrust cover likely lowering dust emission. Likewise, some may have antagonistic interactions. For instance, if carbon is consumed as biomass for livestock production, then carbon storage may be reduced. Ultimately our goal should be to quantify the monetary consequences of specific land use practices for multiple ecosystem services and determine the best land use and adaptive management practices for attaining multiple ecosystem services, minimizing economic detriments, and maximizing economic benefits from multi-commodity rangelands. Our technique is the first step toward this goal, allowing the simultaneous consideration of multiple targeted ecosystem services and properties.

NASA's Plans for Developing Life Support and Environmental Monitoring and Control Systems

NASA Technical Reports Server (NTRS)

Lawson, B. Michael; Jan, Darrell

2006-01-01

Life Support and Monitoring have recently been reworked in response to the Vision for Space Exploration. The Exploration Life Support (ELS) Project has replaced the former Advanced Life Support Element of the Human Systems Research and Technology Office. Major differences between the two efforts include: the separation of thermal systems into a new stand alone thermal project, deferral of all work in the plant biological systems, relocation of food systems to another organization, an addition of a new project called habitation systems, and overall reduction in the number of technology options due to lower funding. The Advanced Environmental Monitoring and Control (AEMC) Element is retaining its name but changing its focus. The work planned in the ELS and AEMC projects is organized around the three major phases of the Exploration Program. The first phase is the Crew Exploration Vehicle (CEV). The ELS and AEMC projects will develop hardware for this short duration orbital and trans-lunar vehicle. The second phase is sortie landings on the moon. Life support hardware for lunar surface access vehicles including upgrades of the CEV equipment and technologies which could not be pursued in the first phase due to limited time and budget will be developed. Monitoring needs will address lunar dust issues, not applicable to orbital needs. The ELS and AEMC equipment is of short duration, but has different environmental considerations. The third phase will be a longer duration lunar outpost. This will consist of a new set of hardware developments better suited for long duration life support and associated monitoring needs on the lunar surface. The presentation will show the planned activities and technologies that are expected to be developed by the ELS and AEMC projects for these program phases.

Lidar characterization of crystalline silica generation and transport from a sand and gravel plant.

PubMed

Trzepla-Nabaglo, Krystyna; Shiraki, Ryoji; Holmén, Britt A

2006-04-30

Light detection and ranging (Lidar) remote sensing two-dimensional vertical and horizontal scans collected downwind of a sand and gravel plant were used to evaluate the generation and transport of geologic fugitive dust emitted by quarry operations. The lidar data give unsurpassed spatial resolution of the emitted dust, but lack quantitative particulate matter (PM) mass concentration data. Estimates of the airborne PM10 and crystalline silica concentrations were determined using linear relationships between point monitor PM10 and quartz content data with the lidar backscatter signal collected from the point monitor location. Lidar vertical profiles at different distances downwind from the plant were used to quantify the PM10 and quartz horizontal fluxes at 2-m vertical resolution as well as off-site emission factors. Emission factors on the order of 65-110 kg of PM10 (10-30 kg quartz) per daily truck activity or 2-4 kg/t product shipped (0.5-1 kg quartz/t) were quantified for this facility. The lidar results identify numerous elevated plumes at heights >30 m and maximum plume heights of 100 m that cannot be practically sampled by conventional point sampler arrays. The PM10 and quartz mass flux was greatest at 10-25 m height and decreased with distance from the main operation. Measures of facility activity were useful for explaining differences in mass flux and emission rates between days. The study results highlight the capabilities of lidar remote sensing for determining the spatial distribution of fugitive dust emitted by area sources with intermittent and spatially diverse dust generation rates.

Dust-Particle Transport in Tokamak Edge Plasmas

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

Pigarov, A Y; Krasheninnikov, S I; Soboleva, T K

2005-09-12

Dust particulates in the size range of 10nm-100{micro}m are found in all fusion devices. Such dust can be generated during tokamak operation due to strong plasma/material-surface interactions. Some recent experiments and theoretical estimates indicate that dust particles can provide an important source of impurities in the tokamak plasma. Moreover, dust can be a serious threat to the safety of next-step fusion devices. In this paper, recent experimental observations on dust in fusion devices are reviewed. A physical model for dust transport simulation, and a newly developed code DUSTT, are discussed. The DUSTT code incorporates both dust dynamics due to comprehensivemore » dust-plasma interactions as well as the effects of dust heating, charging, and evaporation. The code tracks test dust particles in realistic plasma backgrounds as provided by edge-plasma transport codes. Results are presented for dust transport in current and next-step tokamaks. The effect of dust on divertor plasma profiles and core plasma contamination is examined.« less

Free-radical chemistry as a means to evaluate lunar dust health hazard in view of future missions to the moon.

PubMed

Turci, Francesco; Corazzari, Ingrid; Alberto, Gabriele; Martra, Gianmario; Fubini, Bice

2015-05-01

Lunar dust toxicity has to be evaluated in view of future manned missions to the Moon. Previous studies on lunar specimens and simulated dusts have revealed an oxidant activity assigned to HO· release. However, the mechanisms behind the reactivity of lunar dust are still quite unclear at the molecular level. In the present study, a complementary set of tests--including terephthalate (TA) hydroxylation, free radical release as measured by means of the spin-trapping/electron paramagnetic resonance (EPR) technique, and cell-free lipoperoxidation--is proposed to investigate the reactions induced by the fine fraction of a lunar dust analogue (JSC-1A-vf) in biologically relevant experimental environments. Our study proved that JSC-1A-vf is able to hydroxylate TA also in anaerobic conditions, which indicates that molecular oxygen is not involved in such a reaction. Spin-trapping/EPR measures showed that the HO· radical is not the reactive intermediate involved in the oxidative potential of JSC-1A-vf. A surface reactivity implying a redox cycle of phosphate-complexed iron via a Fe(IV) state is proposed. The role of this iron species was investigated by assessing the reactivity of JSC-1A-vf toward hydrogen peroxide (Fenton-like activity), formate ions (homolytic rupture of C-H bond), and linoleic acid (cell-free lipoperoxidation). JSC-1A-vf was active in all tests, confirming that redox centers of transition metal ions on the surface of the dust may be responsible for dust reactivity and that the TA assay may be a useful field probe to monitor the surface oxidative potential of lunar dust.

Climatic factors contributing to long-term variations in surface fine dust concentration in the United States

NASA Astrophysics Data System (ADS)

Pu, Bing; Ginoux, Paul

2018-03-01

High concentrations of dust particles can cause respiratory problems and increase non-accidental mortality. Studies found fine dust (with an aerodynamic diameter of less than 2.5 µm) is an important component of the total PM2.5 mass in the western and central US in spring and summer and has positive trends. This work examines climatic factors influencing long-term variations in surface fine dust concentration in the US using station data from the Interagency Monitoring Protected Visual Environments (IMPROVE) network during 1990-2015. The variations in the fine dust concentration can be largely explained by the variations in precipitation, surface bareness, and 10 m wind speed. Moreover, including convective parameters such as convective inhibition (CIN) and convective available potential energy (CAPE) that reveal the stability of the atmosphere better explains the variations and trends over the Great Plains from spring to fall.While the positive trend of fine dust concentration in the southwestern US in spring is associated with precipitation deficit, the increase in fine dust over the central Great Plains in summer is largely associated with enhanced CIN and weakened CAPE, which are caused by increased atmospheric stability due to surface drying and lower-troposphere warming. The strengthening of the Great Plains low-level jet also contributes to the increase in fine dust concentration in the central Great Plains in summer via its positive correlation with surface winds and negative correlation with CIN.Summer dusty days in the central Great Plains are usually associated with a westward extension of the North Atlantic subtropical high that intensifies the Great Plains low-level jet and also results in a stable atmosphere with subsidence and reduced precipitation.

Long-range Transport of Asian Dust Storms: A Satellite/Surface Perspective on Societal and Scientific Influence

NASA Technical Reports Server (NTRS)

2007-01-01

Among the many components contributing to air pollution, airborne mineral dust plays an important role due to its biogeochemical impact on the ecosystem and its radiative forcing effect on the weather/climate system. As much as one-third to half of the global dust emissions, estimated about 800 Tg, are introduced annually into Earth's atmosphere from various deserts in China. Asian dust storm outbreaks are believed to have persisted for hundreds and thousands years over the vast territory of north and northwest China, but not until recent decades that many studies reveal the compelling evidence in recognizing the importance of these eolian dust particles for forming Chinese Loess Plateau and for biogeochemical cycling in the North Pacific Ocean to as far as in the Greenland ice-sheets through long-range transport. The Asian dust and air pollution aerosols can be detected by its colored appearance on current Earth observing satellites and its evolution monitored by satellite and surface network. In this paper, we will demonstrate the capability of a new satellite algorithm, called Deep Blue, to retrieve aerosol properties, particularly but not limited to, over bright-reflecting surfaces such as urban areas and deserts. Recently, many field campaigns were designed and executed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentrations over eastern Asia and along the rim of the western Pacific. We will provide an overview of the outbreak of Asian dust storms, near source/sink and their evolution along transport pathway, from space and surface observations. The climatic effects and societal impacts of the Asian dusts will be addressed in depth. (to be presented in the International Workshop on Semi-Arid Land Surface-

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.;

High sensitivity of Indian summer monsoon to Middle East dust absorptive properties.

PubMed

Jin, Qinjian; Yang, Zong-Liang; Wei, Jiangfeng

2016-07-28

The absorptive properties of dust aerosols largely determine the magnitude of their radiative impacts on the climate system. Currently, climate models use globally constant values of dust imaginary refractive index (IRI), a parameter describing the dust absorption efficiency of solar radiation, although it is highly variable. Here we show with model experiments that the dust-induced Indian summer monsoon (ISM) rainfall differences (with dust minus without dust) change from -9% to 23% of long-term climatology as the dust IRI is changed from zero to the highest values used in the current literature. A comparison of the model results with surface observations, satellite retrievals, and reanalysis data sets indicates that the dust IRI values used in most current climate models are too low, tending to significantly underestimate dust radiative impacts on the ISM system. This study highlights the necessity for developing a parameterization of dust IRI for climate studies.

An Assessment of Dust Effects on Planetary Surface Systems to Support Exploration Requirements

NASA Technical Reports Server (NTRS)

Wagner, Sandy

2004-01-01

Apollo astronauts learned first hand how problems with dust impact lunar surface missions. After three days, lunar dust contamination on EVA suit bearings led to such great difficulty in movement that another EVA would not have been possible. Dust clinging to EVA suits was transported into the Lunar Module. During the return trip to Earth, when micro gravity was reestablished, the dust became airborne and floated through the cabin. Crews inhaled the dust and it irritated their eyes. Some mechanical systems aboard the spacecraft were damaged due to dust contamination. Study results obtained by Robotic Martian missions indicate that Martian surface soil is oxidative and reactive. Exposures to the reactive Martian dust will pose an even greater concern to the crew health and the integrity of the mechanical systems. As NASA embarks on planetary surface missions to support its Exploration Vision, the effects of these extraterrestrial dusts must be well understood and systems must be designed to operate reliably and protect the crew in the dusty environments of the Moon and Mars. The AIM Dust Assessment Team was tasked to identify systems that will be affected by the respective dust, how they will be affected, associated risks of dust exposure, requirements that will need to be developed, identified knowledge gaps, and recommended scientific measurements to obtain information needed to develop requirements, and design and manufacture the surface systems that will support crew habitation in the lunar and Martian outposts.

The LCO/Gemini-South campaign for Deep Impact target Comet 9P/Tempel 1: Temporally resolved wide-field narrowband imaging results

NASA Astrophysics Data System (ADS)

Lederer, S. M.; Osip, D. J.; Thomas-Osip, J. E.; DeBuizer, J. M.; Mondragon, L. A.; Schweiger, D. L.; Viehweg, J.; SB Collaboration

2005-08-01

An extensive observing campaign to monitor Comet 9P/Tempel 1 will be conducted from 20 June to 19 July, 2005 at Las Campanas Observatory, Chile. These observations will precede and follow the impact of the Deep Impact projectile, which is likely to create a crater on the nucleus that will act as a fresh active area on the surface of the comet. Discreet nucleus active areas, believed to be the source of coma gas and dust jets, will likely result in changing morphology in the coma. We present the initial results of the wide-field narrowband visible imaging of the comet. Data will be taken with the 2.5m DuPont telescope from 27 June - 9 July, following the comet from 4 rotations prior to impact, to 4 rotations after impact using the narrowband Hale-Bopp filters, including CN, C2, and two continuum filters. These data will allow an accurate determination of the rotation state of the embedded nucleus immediately preceding the impact event as well as a measure of any changes to the rotation state due to the impact. In addition, modeling of these data will provide the total dust and gas production rates from the unaltered nucleus compared to the enhanced dust and gas emission from the newly created active region and freely sublimating pieces of mantle material ejected into the coma by the impactor. We will monitor temporal changes (on hours and days time-scales) in the morphology of both the gas and refractory components. We will use coma morphology studies to estimate the dust and gas outflow velocities and infer the presence of discreet nucleus source regions (pre- and post-impact). Of particular interest is the study of the gas-to-dust ratio and the ratio of the minor carbon species emitted from the newly created active region relative to the pre-impact coma environment.

15 years of monitoring occupational exposure to respirable dust and quartz within the European industrial minerals sector.

PubMed

Zilaout, Hicham; Vlaanderen, Jelle; Houba, Remko; Kromhout, Hans

2017-07-01

In 2000, a prospective Dust Monitoring Program (DMP) was started in which measurements of worker's exposure to respirable dust and quartz are collected in member companies from the European Industrial Minerals Association (IMA-Europe). After 15 years, the resulting IMA-DMP database allows a detailed overview of exposure levels of respirable dust and quartz over time within this industrial sector. Our aim is to describe the IMA-DMP and the current state of the corresponding database which due to continuation of the IMA-DMP is still growing. The future use of the database will also be highlighted including its utility for the industrial minerals producing sector. Exposure data are being obtained following a common protocol including a standardized sampling strategy, standardized sampling and analytical methods and a data management system. Following strict quality control procedures, exposure data are consequently added to a central database. The data comprises personal exposure measurements including auxiliary information on work and other conditions during sampling. Currently, the IMA-DMP database consists of almost 28,000 personal measurements which have been performed from 2000 until 2015 representing 29 half-yearly sampling campaigns. The exposure data have been collected from 160 different worksites owned by 35 industrial mineral companies and comes from 23 European countries and approximately 5000 workers. The IMA-DMP database provides the European minerals sector with reliable data regarding worker personal exposures to respirable dust and quartz. The database can be used as a powerful tool to address outstanding scientific issues on long-term exposure trends and exposure variability, and importantly, as a surveillance tool to evaluate exposure control measures. The database will be valuable for future epidemiological studies on respiratory health effects and will allow for estimation of quantitative exposure response relationships. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

Spitzer's Complete History of SN 1987A

NASA Astrophysics Data System (ADS)

Dwek, Eli; Arendt, Richard; Bouchet, Patrice; Danziger, John; Gehrz, Robert; Park, Sangwook; Woodward, Charles

2018-05-01

We propose to use a total of 0.4 hr to obtain 3.6 and 4.5 micron photometry of SNR 1987A at two final epochs between 11666 and 11968 days after the explosion. SN 1987A has been monitored at approximately 6 month intervals throughout the Spitzer mission. The latest IRAC data clearly show that at 3.6 and 4.5 micron, the SN emission has peaked and is now in decline. Continued observation of SN 1987A will allow us to track the decline as the blast wave moves completely past the equatorial ring (ER). The rate at which new dust is swept up should be dropping to zero, and as the presently swept up dust is gradually destroyed (or cools) the emission should continue to fade. The dust traced at these wavelengths is thought to be collisionally-heated by the SN blast wave that also gives rise to the soft X-ray emission from the ER. Early in the mission, the intensity of the mid-IR emission (24 micron) was generally well correlated with that of the X-ray emission. However, the 3.6 and 4.5 micron emission are no longer tracking the brightness of the soft X-ray emission. These differences could stem from a variety of causes, including the sputtering of the dust or changes in the morphology of the ER. Ongoing X-ray observations of the remnant are taking place. Supplementing these with IR observations is essential for determining the spatial distribution, nature, and evolution of this hot dust component. Additionally, the observations may still reveal the appearance of a new emission component from the SN ejecta which are currently interacting with the reverse shock. These observations will complete the record of Spitzer's observations of SN 1987A, spanning more than 16 years from launch to end of mission. They also provide an essential bridge to future monitoring with JWST, which will follow in Spitzer's footsteps.

Overview of the LADEE Ultraviolet-visible Spectrometer: Design, Performance and Planned Operations

NASA Technical Reports Server (NTRS)

Colaprete, A.; Elphic, R. C.; Landis, D.; Karcz, J.; Osetinsky, L.; Shirley, M.; Vargo, K.; Wooden, D.

2013-01-01

The Lunar Atmosphere and Dust Environment Explorer (LADEE) is an orbital lunar science mission currently under development to address the goals of the 2003 National Research Council decadal survey, the Lunar Exploration Analysis Group Roadmap, and the "Scientific Context for Exploration of the Moon" (SCEM) report, and has been recommended for execution by the 2011 Planetary Missions Decadal Survey. The mission s focus is to study the pristine state of the lunar atmosphere and dust environment prior to possible lunar exploration activities by countries, including the United States, China, India, and Japan, among others. Activity on the lunar surface has the potential of altering the tenuous lunar atmosphere, but changing the type and concentration of gases in the atmosphere. Before these activities occur it is important to make measurements of the current lunar atmosphere in its unmodified state. LADEE will determine the composition of the lunar atmosphere and investigate the processes that control its distribution and variability, including sources, sinks, and surface interactions. It will monitor variations in known gases, such as sodium, potassium, argon and helium, and will search for other, as-yet-undetected gases of both lunar and extra-lunar origin. LADEE will also determine whether dust is present in the lunar exosphere, and reveal the processes that contribute to its sources and variability. Launch is planned for August, 2013.

Data Report for Monitoring at Six West Virginia Marcellus Shale Development Sites using NETL’s Mobile Air Monitoring Laboratory (July–November 2012)

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

Pekney, Natalie J.; Reeder, Matthew; Veloski, Garret A.

The West Virginia Department of Environmental Protection’s Office of Oil and Gas was directed according to the Natural Gas Horizontal Well Control Act of December 14, 2011 (West Virginia Code §22-6A) to conduct studies of horizontal well drilling activities related to air quality. The planned study, “Noise, Light, Dust, Volatile Organic Compounds Related to Well Location Restrictions,” required determination of the effectiveness of a 625 ft minimum set-back from the center of the pad of a horizontal well drilling site to the nearest occupied dwelling. An investigation was conducted at seven drilling sites by West Virginia University (WVU) and themore » National Energy Technology Laboratory (NETL) to collect data on dust, hydrocarbon compounds and on noise, radiation, and light levels. NETL’s role in this study was to collect measurements of ambient pollutant concentrations at six of the seven selected sites using NETL’s Mobile Air Monitoring Laboratory. The trailer-based laboratory was situated a distance of 492–1,312 ft from each well pad, on which activities included well pad construction, vertical drilling, horizontal drilling, hydraulic fracturing, and flaring, with the objective of evaluating the air quality impact of each activity for 1–4 weeks per site. Measured pollutants included volatile organic compounds (VOCs), coarse and fine particulate matter (PM 10 and PM 2.5, respectively), ozone, methane (CH 4), carbon dioxide (CO 2), carbon isotopes of CH 4 and CO 2, organic carbon (OC), elemental carbon (EC), oxides of nitrogen (NOx), and sulfur dioxide (SO 2).« less

Source reconciliation of atmospheric dust causing visibility impairment in Class I areas of the western United States

NASA Astrophysics Data System (ADS)

Kavouras, Ilias G.; Etyemezian, Vicken; Dubois, David W.; Xu, Jin; Pitchford, Marc

2009-01-01

Aerosol data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network, air mass backward trajectories, land use maps, soil characteristics maps, diagnostic ratios of elemental composition, and multivariate linear regression were utilized as part of a semiquantitative analysis. The purpose of the analysis was to determine the types of dust-causing events that contribute to low visibility at a given site when the sum of extinction from coarse mass (CM) and fine soil (FS) was larger than any other aerosol component and the reconstructed aerosol extinction coefficient was among the 20% highest (calculated on a calendar year basis) for that site. For these "worst dust days," the above tools were used to ascribe the cause of low visibility to one of the following types of events: (1) transcontinental transport of dust originating from Asia; (2) windblown dust events from sources located nearby the site and; (3) transport of windblown dust from sources upwind of the site. Depending on the weight of evidence, a low or high level of confidence was associated with the assignment of one of these three events. Absence of convincing evidence resulted in ascribing the worst dust day to "undetermined events." Of the 610 worst dust days over the 2001-2003 period, 51% were associated with one of the three event types with high confidence and an additional 30% were accounted for with low confidence. Of the 496 worst dust days associated with an event (either low or high confidence), Asian dust was the assigned event on 55 days (for 2001-2002), locally generated windblown dust on 201 days, and transport from upwind source areas susceptible to wind erosion on 240 days. Events associated with windblown episodes from source areas in the United States and Mexico exhibited the highest dust concentrations. Asian dust events were associated with lower dust concentrations and a larger FS-to-CM ratio. Some variations between Asian dust and continental North American dust were observed in organic matter (OMC), black carbon (LAC), and nitrate (NO3-) content. None of the tools used in this study was adequate for identifying events associated with mechanically released dust by anthropogenic activities including, agriculture, construction and motor vehicle travel on paved and unpaved roads. Some of the worst dust days may have been caused by these types of activities, especially in central Arizona and northern and Southern California, where the fraction of undetermined events was higher than in other regions within the western United States. All in all, the methods and results of this study can help improve the performance of large-scale dust emission models and provide insight into the distribution of the types of events that cause dust resultant haze in relatively remote areas of the western United States.

Real-time PM10 concentration monitoring on Penang Bridge by using traffic monitoring CCTV

NASA Astrophysics Data System (ADS)

Low, K. L.; Lim, H. S.; MatJafri, M. Z.; Abdullah, K.; Wong, C. J.

2007-04-01

For this study, an algorithm was developed to determine concentration of particles less than 10μm (PM10) from still images captured by a CCTV camera on the Penang Bridge. The objective of this study is to remotely monitor the PM10 concentrations on the Penang Bridge through the internet. So, an algorithm was developed based on the relationship between the atmospheric reflectance and the corresponding air quality. By doing this, the still images were separated into three bands namely red, green and blue and their digital number values were determined. A special transformation was then performed to the data. Ground PM10 measurements were taken by using DustTrak TM meter. The algorithm was calibrated using a regression analysis. The proposed algorithm produced a high correlation coefficient (R) and low root-mean-square error (RMS) between the measured and produced PM10. Later, a program was written by using Microsoft Visual Basic 6.0 to download still images from the camera over the internet and implement the newly developed algorithm. Meanwhile, the program is running in real time and the public will know the air pollution index from time to time. This indicates that the technique using the CCTV camera images can provide a useful tool for air quality studies.

EPA Requires Beemsterboer and KCBX to Take Action

EPA Pesticide Factsheets

In response to complaints of fugitive pet coke dust, EPA issued Clean Air Act Section 114 information request letters to KCBX Terminals and Beemsterboer Slag petroleum coke facilities, and ordered onsite air quality monitoring and petcoke sample analysis.

What is EPA Doing about Pet Coke in Chicago?

EPA Pesticide Factsheets

In response to complaints of windblown dust believed to originate from petroleum coke (petcoke) storage pile sites, operated by KCBX Terminals and Beemsterboer Slag; EPA ordered sample analysis and air quality monitoring under the Clean Air Act.

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.

Application of a combined measurement and modeling method to quantify windblown dust emissions from the exposed playa at Mono Lake, California.

PubMed

Ono, Duane; Kiddoo, Phill; Howard, Christopher; Davis, Guy; Richmond, Kenneth

2011-10-01

Particulate matter < or =10 microm (PM10) emissions due to wind erosion can vary dramatically with changing surface conditions. Crust formation, mechanical disturbance, soil texture, moisture, and chemical content of the soil can affect the amount of dust emitted during a wind event. A refined method of quantifying windblown dust emissions was applied at Mono Lake, CA, to account for changing surface conditions. This method used a combination of real-time sand flux monitoring, ambient PM10 monitoring, and dispersion modeling to estimate dust emissions and their downwind impact. The method identified periods with high emissions and periods when the surface was stable (no sand flux), even though winds may have been high. A network of 25 Cox sand catchers (CSCs) was used to measure the mass of saltating particles to estimate sand flux rates across a 2-km2 area. Two electronic sensors (Sensits) were used to time-resolve the CSC sand mass to estimate hourly sand flux rates, and a perimeter tapered element oscillating microbalance (TEOM) monitor measured hourly PM10 concentrations. Hourly sand flux rates were related by dispersion modeling to hourly PM10 concentrations to back-calculate the ratio of vertical PM10 flux to horizontal sand flux (K-factors). Geometric mean K-factor values (K(f)) were found to change seasonally, ranging from 1.3 x 10(-5) to 5.1 x 10(-5) for sand flux measured at 15 cm above the surface (q15). Hourly PM10 emissions, F, were calculated by applying seasonal K-factors to sand flux measurements (F = K(f) x q15). The maximum hourly PM10 emission rate from the study area was 76 g/m2 x hr (10-m wind speed = 23.5 m/sec). Maximum daily PM10 emissions were estimated at 450 g/m2 x day, and annual emissions at 1095 g/m2 x yr. Hourly PM10 emissions were used by the U.S. Environmental Protection Agency (EPA) guideline AERMOD dispersion model to estimate downwind ambient impacts. Model predictions compared well with monitor concentrations, with hourly PM10 ranging from 16 to over 60,000 microg/m3 (slope = 0.89, R2 = 0.77).

Improving dust emission characterization in dust models using dynamic high-resolution geomorphic erodibility map

NASA Astrophysics Data System (ADS)

Parajuli, S. P.; Yang, Z.; Kocurek, G.

2013-12-01

Dust is known to affect the earth radiation budget, biogeochemical cycle, precipitation, human health and visibility. Despite the increased research effort, dust emission modeling remains challenging because dust emission is affected by complex geomorphological processes. Existing dust models overestimate dust emission and rely on tuning and a static erodibility factor in order to make simulated results comparable to remote sensing and ground-based observations. In most of current models, dust emission is expressed in terms of threshold friction speed, which ultimately depends mainly upon the percentage clay content and soil moisture. Unfortunately, due to the unavailability of accurate and high resolution input data of the clay content and soil moisture, estimated threshold friction speed commonly does not represent the variability in field condition. In this work, we attempt to improve dust emission characterization by developing a high resolution geomorphic map of the Middle East and North Africa (MENA), which is responsible for more than 50% of global dust emission. We develop this geomorphic map by visually examining high resolution satellite images obtained from Google Earth Pro and ESRI base map. Albeit subjective, our technique is more reliable compared to automatic image classification technique because we incorporate knowledge of geological/geographical setting in identifying dust sources. We hypothesize that the erodibility is unique for different geomorphic landforms and that it can be quantified by the correlation between observed wind speed and satellite retrieved aerosol optical depth (AOD). We classify the study area into several key geomorphological categories with respect to their dust emission potential. Then we quantify their dust emission potential using the correlation between observed wind speed and satellite retrieved AOD. The dynamic, high-resolution geomorphic erodibility map thus prepared will help to reduce the uncertainty in current dust models associated with poor characterization of dust sources. The baseline dust scheme used in this study is the Dust Entrainment and Deposition (DEAD) model, which is also a component of the community land model (CLM). Proposed improvements in the dust emission representation will help to better understand the accurate effect of dust on climate processes.

Lidar Remote Sensing for Industry and Environment Monitoring

NASA Technical Reports Server (NTRS)

Singh, Upendra N. (Editor); Itabe, Toshikazu (Editor); Sugimoto, Nobuo (Editor)

2000-01-01

Contents include the following: 1. Keynote paper: Overview of lidar technology for industrial and environmental monitoring in Japan. 2. lidar technology I: NASA's future active remote sensing mission for earth science. Geometrical detector consideration s in laser sensing application (invited paper). 3. Lidar technology II: High-power femtosecond light strings as novel atmospheric probes (invited paper). Design of a compact high-sensitivity aerosol profiling lidar. 4. Lasers for lidars: High-energy 2 microns laser for multiple lidar applications. New submount requirement of conductively cooled laser diodes for lidar applications. 5. Tropospheric aerosols and clouds I: Lidar monitoring of clouds and aerosols at the facility for atmospheric remote sensing (invited paper). Measurement of asian dust by using multiwavelength lidar. Global monitoring of clouds and aerosols using a network of micropulse lidar systems. 6. Troposphere aerosols and clouds II: Scanning lidar measurements of marine aerosol fields at a coastal site in Hawaii. 7. Tropospheric aerosols and clouds III: Formation of ice cloud from asian dust particles in the upper troposphere. Atmospheric boundary layer observation by ground-based lidar at KMITL, Thailand (13 deg N, 100 deg. E). 8. Boundary layer, urban pollution: Studies of the spatial correlation between urban aerosols and local traffic congestion using a slant angle scanning on the research vessel Mirai. 9. Middle atmosphere: Lidar-observed arctic PSC's over Svalbard (invited paper). Sodium temperature lidar measurements of the mesopause region over Syowa Station. 10. Differential absorption lidar (dIAL) and DOAS: Airborne UV DIAL measurements of ozone and aerosols (invited paper). Measurement of water vapor, surface ozone, and ethylene using differential absorption lidar. 12. Space lidar I: Lightweight lidar telescopes for space applications (invited paper). Coherent lidar development for Doppler wind measurement from the International Space Station. 13. Space lidar II: Using coherent Doppler lidar to estimate river discharge. 14. Poster session: Lidar technology, optics for lidar. Laser for lidar. Middle atmosphere observations. Tropospheric observations (aerosols, clouds). Boundary layer, urban pollution. Differential absorption lidar. Doppler lidar. and Space lidar.

Lightcurve of comet Austin(1989c1) and its dust mantle development

NASA Technical Reports Server (NTRS)

Hasegawa, Hitoshi; Watanabe, Jun-Ichi

1992-01-01

Brightness variations of comet Austin(1989c1) were investigated in terms of the variations of water production rate. We translated the visual brightness data into water production rates using Newburn's semi-empirical law. The curve of the water production rates as a function of heliocentric distance was compared with the model calculations that assumed energy balance between the solar incident and vaporization of water. Thermal flow in a dust mantle at a surface of the nucleus is also included in the model. The model calculations including the dust mantle are more favorable for the observed rate than non-dust mantle cases. The extinction after the perihelion passage suggests that the dust mantle developed gradually.

An Aerobraking Strategy for Determining Mars Upper Atmospheric Structure

NASA Astrophysics Data System (ADS)

Bougher, S. W.; Murphy, J. R.; Haberle, R. M.

1997-07-01

The Mars Global Surveyor (MGS) spacecraft will enter Mars orbit on Sept. 12, 1997, and thereafter undergo aerobraking for roughly 4-months. The final data-taking orbit to be achieved is sun-synchronous (2PM/2AM). An aerobraking strategy has been developed that not only will provide the walk-in capability needed to safely achieve the required Mars orbit, but also will provide a careful monitoring of the atmospheric structure. In particular, the linkage between the lower (0-100 km) and upper (100- 150 km) Mars atmospheres will be investigated. A suite of complementary measurements is planned that will probe the atmosphere over 0-150 km, including : (1) MGS Accelerometer density and inferred temperatures (100-150 km), (2) MGS Thermal Emission Spectrometer (TES) nadir (25-30 km) and limb (up to about 55 km) temperatures, (3) MGS Electron Reflectometer (ER) F1-peak heights (near 130 km), (4) ground-based microwave disk-averaged temperatures (0-70 km), and (5) Mars Pathfinder (MPF) surface meteorological data at 20 N latitude. These datasets acquired during the aerobraking phase will enable the current state of the atmosphere to be examined. Potential dust storm activity and its manifestations throughout the atmosphere can be monitored over Ls = 184 to 250. A corresponding library of coupled 3-D model simulations, based upon the NASA Ames Mars GCM and the NCAR Mars Thermospheric GCM (MTGCM), will be used to : (1) validate the current state of the Mars atmosphere, (2) investigate the various orbital, seasonal, LAT-LT-LON, and potential dust storm trends, and (3) predict the structure of the Mars atmosphere in the aerobraking corridor that is approaching in future MGS orbits. The in-situ accelerometer and ER data will eventually be used to construct a Mars empirical model covering 100-150 km. We will present a few selected GCM simulations to illustrate the expected atmospheric response to a dust storm event. In addition, we will discuss why these upper atmosphere datasets are important to future Mars missions.

Determining the spatial variability of personal sampler inlet locations.

PubMed

Vinson, Robert; Volkwein, Jon; McWilliams, Linda

2007-09-01

This article examines the spatial variability of dust concentrations within a coal miner's breathing zone and the impact of sampling location at the cap lamp, nose, and lapel. Tests were conducted in the National Institute for Safety and Health Pittsburgh Research Laboratory full-scale, continuous miner gallery using three prototype personal dust monitors (PDM). The dust masses detected by the PDMs were used to calculate the percentage difference of dust mass between the cap lamp and the nose and between the lapel and the nose. The calculated percentage differences of the masses ranged from plus 12% to minus 25%. Breathing zone tests were also conducted in four underground coal mines using the torso of a mannequin to simulate a miner. Coal mine dust was sampled with multi-cyclone sampling cans mounted directly in front of the mannequin near the cap lamp, nose, and lapel. These four coal mine tests found that the spatial variability of dust levels and imprecision of the current personal sampler is a greater influence than the sampler location within the breathing zone. However, a one-sample t-test of this data did find that the overall mean value of the cap lamp/nose ratio was not significantly different than 1 (p-value = 0.21). However, when applied to the overall mean value of the lapel/nose ratio there was a significant difference from 1 (p-value < .0001). This finding is important because the lapel has always been the sampling location for coal mine dust samples. But these results suggest that the cap location is slightly more indicative of what is breathed through the nose area.

Impact of cross-field motion on ablation of high-Z dust in fusion edge plasmas

DOE PAGES

Smirnov, R. D.; Krasheninnikov, S. I.

2017-07-05

The impact of cross-field motion of high-Z dust grains on their shielding by ablation cloud in edge plasmas of tokamaks is analyzed. The modification of the existing high-Z dust shielding theory is developed, which takes the dust motion effects into account. We show that the cross-field motion can lead to a large factor increase of the dust ablation rate, as compared to the previous model. It is also shown that the motion effects take place when the dust cross-field velocity exceeds a threshold value. We also obtain the dependencies of the dust ablation flux on the dust velocity and ofmore » the threshold velocity on the dust size and the ambient plasma temperature.« less

Impact of cross-field motion on ablation of high-Z dust in fusion edge plasmas

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

Smirnov, R. D.; Krasheninnikov, S. I.

The impact of cross-field motion of high-Z dust grains on their shielding by ablation cloud in edge plasmas of tokamaks is analyzed. The modification of the existing high-Z dust shielding theory is developed, which takes the dust motion effects into account. We show that the cross-field motion can lead to a large factor increase of the dust ablation rate, as compared to the previous model. It is also shown that the motion effects take place when the dust cross-field velocity exceeds a threshold value. We also obtain the dependencies of the dust ablation flux on the dust velocity and ofmore » the threshold velocity on the dust size and the ambient plasma temperature.« less

Particle-Image Velocimeter Having Large Depth of Field

NASA Technical Reports Server (NTRS)

Bos, Brent

2009-01-01

An instrument that functions mainly as a particle-image velocimeter provides data on the sizes and velocities of flying opaque particles. The instrument is being developed as a means of characterizing fluxes of wind-borne dust particles in the Martian atmosphere. The instrument could also adapted to terrestrial use in measuring sizes and velocities of opaque particles carried by natural winds and industrial gases. Examples of potential terrestrial applications include monitoring of airborne industrial pollutants and airborne particles in mine shafts. The design of this instrument reflects an observation, made in field research, that airborne dust particles derived from soil and rock are opaque enough to be observable by use of bright field illumination with high contrast for highly accurate measurements of sizes and shapes. The instrument includes a source of collimated light coupled to an afocal beam expander and an imaging array of photodetectors. When dust particles travel through the collimated beam, they cast shadows. The shadows are magnified by the beam expander and relayed to the array of photodetectors. Inasmuch as the images captured by the array are of dust-particle shadows rather of the particles themselves, the depth of field of the instrument can be large: the instrument has a depth of field of about 11 mm, which is larger than the depths of field of prior particle-image velocimeters. The instrument can resolve, and measure the sizes and velocities of, particles having sizes in the approximate range of 1 to 300 m. For slowly moving particles, data from two image frames are used to calculate velocities. For rapidly moving particles, image smear lengths from a single frame are used in conjunction with particle- size measurement data to determine velocities.

High Resolution IRAS Maps and IR Emission of M31 -- II. Diffuse Component and Interstellar Dust

NASA Technical Reports Server (NTRS)

Xu, C.; Helou, G.

1995-01-01

Large-scale dust heating and cooling in the diffuse medium of M31 is studied using the high resolution (HiRes) IRAS maps in conjunction with UV, optical (UBV), and the HI maps. A dust heating/cooling model is developed based on a radiative transfer model which assumes a 'Sandwich' configuration of dust and stars takes account of the effect of dust grain scattering.

Application of the Gillette model for windblown dust at Owens Lake, CA

NASA Astrophysics Data System (ADS)

Ono, Duane

Windblown dust can have significant impacts on local air pollution levels, and in cases such as dust from Africa or Asia, can have global impacts on our environment. Models to estimate particulate matter emissions from windblown dust are generally based on the local wind speed, the threshold wind speed to initiate erosion, and the soil texture of a given surface. However, precipitation, soil crusting, and soil disturbance can dramatically change the threshold wind speed and erosion potential of a surface, making modeling difficult. A low-cost sampling and analysis method was developed to account for these surface changes in a wind erosion model. Windblown dust emissions measured as PM 10 (particulate matter less than a nominal 10 μm aerodynamic diameter) have been found to be generally proportional to sand flux (also known as saltation flux). In this study, a model was used to estimate sand flux using the relationship Q=AρG/g, where Q is horizontal sand flux, A is a surface erosion potential factor, ρ is air density, g is the gravitational constant, and G=∫ u*(u*2-u*t2)dt, where u* is friction velocity and u is the threshold friction velocity of the surface. The variable A in the model was derived by comparing the measured sand flux for a given period and area to G for the same period. Sand flux was monitored at Owens Lake, CA using low-cost Cox Sand Catchers (CSCs) for monthly measurements, and more expensive electronic sensors (Sensits) to measure hourly flux rates and u. Monitors were spaced 1 km apart at 114 sites, covering one clay and three sand-dominated soil areas. Good model results relied primarily on the erosion potential A, which could be determined from CSC measurements and wind speed data. Annual values for A were found to range from 1.3 to 3.5 in the three sand areas. The value of A was an order of magnitude lower (0.2) in the less erodible clay area. Previous studies showed similar values for A of 0.7 and 2.9 for a sandy site at Owens Lake, and 1.1 for a site in the Chihuahuan desert in New Mexico. The model performed well using annual values for A and better with monthly values, with R2 ranging from 0.74 to 0.87 for hourly sand flux rates in the four study areas. Monthly changes in A accounted for temporal surface changes, such as precipitation and surface crusting in the model predictions. This study demonstrated that low-cost periodic sand flux sampling using CSCs can provide a practical method to determine values for A in a simple wind erosion model, and that this model can provide good hourly and monthly estimates of sand flux rates in windblown dust areas.

Coagulation of dust grains in the plasma of an RF discharge in argon

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

Mankelevich, Yu. A.; Olevanov, M. A.; Pal', A. F.

2009-03-15

Results are presented from experimental studies of coagulation of dust grains of different sizes injected into a low-temperature plasma of an RF discharge in argon. A theoretical model describing the formation of dust clusters in a low-temperature plasma is developed and applied to interpret the results of experiments on the coagulation of dust grains having large negative charges. The grain size at which coagulation under the given plasma conditions is possible is estimated using the developed theory. The theoretical results are compared with the experimental data.

Inter-annual changes of Biomass Burning and Desert Dust and their impact over East Asia

NASA Astrophysics Data System (ADS)

DONG, X.; Fu, J. S.; Huang, K.

2014-12-01

Impact of mineral dust and biomass burning aerosols on air quality has been well documented in the last few decades, but the knowledge about their interactions with anthropogenic emission and their impacts on regional climate is very limited (IPCC, 2007). While East Asia is greatly affected by dust storms in spring from Taklamakan and Gobi deserts (Huang et al., 2010; Li et al., 2012), it also suffers from significant biomass burning emission from Southeast Asia during the same season. Observations from both surface monitoring and satellite data indicated that mineral dust and biomass burning aerosols may approach to coastal area of East Asia simultaneously, thus have a very unique impact on the local atmospheric environment and regional climate. In this study, we first investigated the inter-annual variations of biomass burning and dust aerosols emission for 5 consecutive years from 2006-2010 to estimate the upper and lower limits and correlation with meteorology conditions, and then evaluate their impacts with a chemical transport system. Our preliminary results indicated that biomass burning has a strong correlation with precipitation over Southeast Asia, which could drive the emission varying from 542 Tg in 2008 to 945 Tg in 2010, according to FLAMBE emission inventory (Reid et al., 2009). Mineral dust also demonstrated a strong dependence on wind filed. These inter-annual/annual variations will also lead to different findings and impacts on air quality in East Asia. Reference: Huang, K., et al. (2010), Mixing of Asian dust with pollution aerosol and the transformation of aerosol components during the dust storm over China in spring 2007, Journal of Geophysical Research-Atmospheres, 115. IPCC (2007), Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, New York. Li, J., et al. (2012), Mixing of Asian mineral dust with anthropogenic pollutants over East Asia: a model case study of a super-duststorm in March 2010, Atmospheric Chemistry and Physics, 12, 7591-7607.

Assessment of penetration through vacuum cleaners and recommendation of wet cyclone technology.

PubMed

Seo, Youngjin; Han, Taewon

2013-04-01

In many commercial vacuum cleaners, the captured aerosol particles contained in the dust collector may accidentally release from the exhaust filtration owing to leakage or penetration. Vacuum cleaners may cause dust to become airborne by exhausting air that is not completely filtered. This may cause the operator to inhale dust, in turn causing health problems. This study aimed to investigate the dust penetration rates from three commercial vacuum cleaners and suggest the best technique for completely filtering exhaust air using a combination of cyclonic separation and water filtration. The commercial vacuum cleaners were tested inside a custom-built hood, and the exhausted particles were monitored using a sampling probe in conjunction with an aerosol particle sizer Quartzose mineral dusts were added to each vacuum cleaner through the dust transport line. A 2400 L/min wet cyclone was employed as the proposed vacuum cleaner It was designed using Stokes scaling, and its collection characteristics were evaluated using polystyrene latex beads. Surprisingly, the conventional vacuum cleaners failed to capture an overall average of approximately 14% of the particles in the given size range. However, only approximately 3.8% of the collected particles escaped from the vacuum cleaner that used the wet cyclone technology. Thus, the proposed vacuum cleaner should potentially be an effective method for vacuuming household dust. The successful investigation of conventional vacuum cleaners is useful for both manufacturers and users. As an effective vacuum cleaning mechanism, household dust is able to migrate along the thin water, film that forms on the inner walls of the cyclone vacuum cleaner. It collects dust in a small water inflow (3 mL/min), which allows it to capture a higher percentage of contaminants than most of the currently available vacuum cleaners. The significantly low accidental exposure rates achieved by this new vacuum cleaner enable healthy conditions in various environments, including indoors.

Glacial/interglacial changes of Southern Hemisphere wind circulation from the geochemistry of South American dust

NASA Astrophysics Data System (ADS)

Gili, Stefania; Gaiero, Diego M.; Goldstein, Steven L.; Chemale, Farid; Jweda, Jason; Kaplan, Michael R.; Becchio, Raúl A.; Koester, Edinei

2017-07-01

The latitudinal displacement of the southern westerlies and associated climate systems is a key parameter for understanding the variations of Southern Hemisphere atmospheric circulation during the Late Quaternary Period. To increase understanding of past atmospheric circulation and of the paleo-environmental conditions associated with continental dust sources, we dig deeper into dust provenance in paleo-archives of the Southern Hemisphere. We present here a Sr-Nd isotopic and rare earth element study of surface sediments collected along a ∼4000 km latitudinal band from arid and semi-arid terrains in southern South America. Findings from terrains that served as paleo-dust suppliers are compared with modern dust collected from monitoring stations along the same latitudinal band, which affords a test on how actual present-day aeolian compositions compare to those of the past potential source areas. Moreover, the comparison between past and present-day datasets is useful for understanding present-day atmospheric circulation. Armed with a new comprehensive dataset, we revise previous interpretations of the provenance of dust trapped in the Antarctic ice and sediments deposited in the South Atlantic sector of the Southern Ocean. These comparisons support multiple source regions in southern South America that changed with climates. The findings reveal that, although Patagonia plays an important role in contributing dust to the higher latitudes, central Western Argentina and (to a lesser extent) the southern Puna region also emerge as potentially important dust sources during glacial times. The southern Altiplano appears to be a major contributor during interglacial periods as well. We rely in part on an understanding of modern wind-dust activities to conclude that the possible presence of southern South America source regions - other than Patagonia - in East Antarctic ice is consistent with an overall equatorward displacement during glacial times of both the mid-latitude westerlies and the subtropical jet stream.

Association between pulmonary function and daily levels of sand dust particles assessed by light detection and ranging in schoolchildren in western Japan: A panel study.

PubMed

Watanabe, Masanari; Noma, Hisashi; Kurai, Jun; Kato, Kazuhiro; Sano, Hiroyuki; Tatsukawa, Toshiyuki; Nakazaki, Hirofumi; Yamasaki, Akira; Shimizu, Eiji

2016-01-01

An important aspect of sand dust emissions in association with respiratory disorders is the quantity of particulate matter. This is usually expressed as particulate matter less than 10 μm (PM10) and 2.5 μm (PM2.5). However, the composition of PM10 and PM2.5 varies. Light detection and ranging is used to monitor sand dust particles originating in East Asian deserts and distinguish them from air pollution aerosols. The objective of this study was to investigate the association between the daily levels of sand dust particles and pulmonary function in schoolchildren in western Japan. In this panel study, the peak expiratory flow (PEF) of 399 schoolchildren was measured daily from April to May 2012. A linear mixed model was used to estimate the association of PEF with the daily levels of sand dust particles, suspended particulate matter (SPM), and PM2.5. There was no association between the daily level of sand dust particles and air pollution aerosols, while both sand dust particles and air pollution aerosols had a significant association with SPM and PM2.5. An increment of 0.018 km(-1) in sand dust particles was significantly associated with a decrease in PEF (-3.62 L/min; 95% confidence interval, -4.66 to -2.59). An increase of 14.0 μg/m(3) in SPM and 10.7 μg/m(3) in PM2.5 led to a significant decrease of -2.16 L/min (-2.88 to -1.43) and -2.58 L/min (-3.59 to -1.57), respectively, in PEF. These results suggest that exposure to sand dust emission may relate to pulmonary dysfunction in children in East Asia. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Ground and satellite-based remote sensing of mineral dust using AERI spectra and MODIS thermal infrared window brightness temperatures

NASA Astrophysics Data System (ADS)

Hansell, Richard Allen, Jr.

The radiative effects of dust aerosol on our climate system have yet to be fully understood and remain a topic of contemporary research. To investigate these effects, detection/retrieval methods for dust events over major dust outbreak and transport areas have been developed using satellite and ground-based approaches. To this end, both the shortwave and longwave surface radiative forcing of dust aerosol were investigated. The ground-based remote sensing approach uses the Atmospheric Emitted Radiance Interferometer brightness temperature spectra to detect mineral dust events and to retrieve their properties. Taking advantage of the high spectral resolution of the AERI instrument, absorptive differences in prescribed thermal IR window sub-band channels were exploited to differentiate dust from cirrus clouds. AERI data collected during the UAE2 at Al-Ain UAE was employed for dust retrieval. Assuming a specified dust composition model a priori and using the light scattering programs of T-matrix and the finite difference time domain methods for oblate spheroids and hexagonal plates, respectively, dust optical depths have been retrieved and compared to those inferred from a collocated and coincident AERONET sun-photometer dataset. The retrieved optical depths were then used to determine the dust longwave surface forcing during the UAE2. Likewise, dust shortwave surface forcing is investigated employing a differential technique from previous field studies. The satellite-based approach uses MODIS thermal infrared brightness temperature window data for the simultaneous detection/separation of mineral dust and cirrus clouds. Based on the spectral variability of dust emissivity at the 3.75, 8.6, 11 and 12 mum wavelengths, the D*-parameter, BTD-slope and BTD3-11 tests are combined to identify dust and cirrus. MODIS data for the three dust-laden scenes have been analyzed to demonstrate the effectiveness of this detection/separation method. Detected daytime dust and cloud coverage for the Persian Gulf case compare reasonably well to those from the "Deep Blue" algorithm developed at NASA-GSFC. The nighttime dust/cloud detection for the cases surrounding Cape Verde and Niger, West Africa has been validated by comparing to coincident and collocated ground-based micro-pulse lidar measurements.

Integrated spatiotemporal characterization of dust sources and outbreaks in Central and East Asia

NASA Astrophysics Data System (ADS)

Darmenova, Kremena T.

The potential of atmospheric dust aerosols to modify the Earth's environment and climate has been recognized for some time. However, predicting the diverse impact of dust has several significant challenges. One is to quantify the complex spatial and temporal variability of dust burden in the atmosphere. Another is to quantify the fraction of dust originating from human-made sources. This thesis focuses on the spatiotemporal characterization of sources and dust outbreaks in Central and East Asia by integrating ground-based data, satellite multisensor observations, and modeling. A new regional dust modeling system capable of operating over a span of scales was developed. The modeling system consists of a dust module DuMo, which incorporates several dust emission schemes of different complexity, and the PSU/NCAR mesoscale model MM5, which offers a variety of physical parameterizations and flexible nesting capability. The modeling system was used to perform for the first time a comprehensive study of the timing, duration, and intensity of individual dust events in Central and East Asia. Determining the uncertainties caused by the choice of model physics, especially the boundary layer parameterization, and the dust production scheme was the focus of our study. Implications to assessments of the anthropogenic dust fraction in these regions were also addressed. Focusing on Spring 2001, an analysis of routine surface meteorological observations and satellite multi-sensor data was carried out in conjunction with modeling to determine the extent to which integrated data set can be used to characterize the spatiotemporal distribution of dust plumes at a range of temporal scales, addressing the active dust sources in China and Mongolia, mid-range transport and trans-Pacific, long-range transport of dust outbreaks on a case-by-case basis. This work demonstrates that adequate and consistent characterization of individual dust events is central to establishing a reliable climatology, ultimately leading to improved assessments of dust impacts on the environment and climate. This will also help to identify the appropriate temporal and spatial scales for adequate intercomparison between model results and observational data as well as for developing an integrated analysis methodology for dust studies.

Pheromonal Communication in the European House Dust Mite, Dermatophagoides pteronyssinus

PubMed Central

Steidle, Johannes L.M.; Barcari, Elena; Hradecky, Marc; Trefz, Simone; Tolasch, Till; Gantert, Cornelia; Schulz, Stefan

2014-01-01

Despite the sanitary importance of the European house dust mite Dermatophagoides pteronyssinus (Trouessart, 1897), the pheromonal communication in this species has not been sufficiently studied. Headspace analysis using solid phase micro extraction (SPME) revealed that nerol, neryl formate, pentadecane, (6Z,9Z)-6,9-heptadecadiene, and (Z)-8-heptadecene are released by both sexes whereas neryl propionate was released by males only. Tritonymphs did not produce any detectable volatiles. In olfactometer experiments, pentadecane and neryl propionate were attractive to both sexes as well as to tritonymphs. (Z)-8-heptadecene was only attractive to male mites. Therefore it is discussed that pentadecane and neryl propionate are aggregation pheromones and (Z)-8-heptadecene is a sexual pheromone of the European house dust mite D. pteronyssinus. To study the potential use of pheromones in dust mite control, long-range olfactometer experiments were conducted showing that mites can be attracted to neryl propionate over distances of at least 50 cm. This indicates that mite pheromones might be useable to monitor the presence or absence of mites in the context of control strategies. PMID:26462831

Influence of the atmospheric opacity cycle on the near surface environment of Gale Crater on Mars

NASA Astrophysics Data System (ADS)

de la Torre Juarez, Manuel; Gomez-Elvira, Javier; Guzewich, Scott David; Lemmon, Mark T.; Martinez, German; Mason, Emily; Navarro, Sara; Newman, Claire E.; Smith, Michael D.; Retortillo, Alvaro de Vicente

2016-10-01

The Mars atmospheric dust changes the capacity of the atmosphere to absorb solar radiation or release outgoing thermal infrared radiation. This alters the atmospheric heat exchange fluxes and can interfere with the global circulation. The response of near surface pressure, temperature and winds has been characterized at the higher northern latitudes of 45 degree N at the Viking landing sites. The Rover Environmental Monitoring Station (REMS) on Curiosity allows a similar characterization at near-equatorial latitudes of 4.5 degree S. Using MCAM-880 nm opacities as a measure of local atmospheric dust load, we analyze the response of changes in surface variables measured by REMS and compare to those observed by Viking. As on Viking, diurnal and semidiurnal pressure tide amplitudes track very closely the atmospheric opacity and the mean daily pressure shows the increased wave activity. Temperature tides show a more complex response that combines its sensitivity to changes in dust and cloud opacities. Differences in UV opacities for the REMS set of finite spectral windows are explored during the dust and clear seasons.

Photoemission Experiments for Charge Characteristics of Individual Dust Grains

NASA Technical Reports Server (NTRS)

Abbas, M. M.; Craven, P. D.; Spann, J. F.; West, E.; Pratico, J.; Tankosic, D.; Venturini, C. C.; Six, N. Frank (Technical Monitor)

2001-01-01

Photoemission experiments with UV radiation have been performed to investigate the microphysics and charge characteristics of individual isolated dust grains of various compositions and sizes by using the electrodynamic balance facility at NASA Marshall Space Flight Center. Dust particles of 2-10 gm diameter are levitated in a vacuum chamber at pressures approximately 10(exp-5) torr and exposed to a collimated beam of UV radiation in the 120-200 nm spectral range from a deuterium lamp source with a MgF2 window. A monochromator is used to select the UV wavelength with a spectral resolution of 8 nm. The electrodynamic facility permits measurements of the charge and diameters of particles of known composition, and monitoring of photoemission rates with the incident UV radiation. Experiments have been conducted on test particles of silica and polystyrene to determine the photoelectric yields and surface equilibrium potentials when exposed to UV radiation. A brief description of an experimental procedure for photoemission studies is given and some preliminary laboratory measurements of the photoelectric yields of individual dust particles are presented.

Combustibility Determination for Cotton Gin Dust and Almond Huller Dust.

PubMed

Hughs, Sidney E; Wakelyn, Phillip J

2017-04-26

It has been documented that some dusts generated while processing agricultural products, such as grain and sugar, can constitute combustible dust hazards. After a catastrophic dust explosion in a sugar refinery in 2008, the Occupational Safety and Health Administration (OSHA) initiated action to develop a mandatory standard to comprehensively address the fire and explosion hazards of combustible dusts. Cotton fiber and related materials from cotton ginning, in loose form, can support smoldering combustion if ignited by an outside source. However, dust fires and other more hazardous events, such as dust explosions, are unknown in the cotton ginning industry. Dust material that accumulates inside cotton gins and almond huller plants during normal processing was collected for testing to determine combustibility. Cotton gin dust is composed of greater than 50% inert inorganic mineral dust (ash content), while almond huller dust is composed of at least 7% inert inorganic material. Inorganic mineral dust is not a combustible dust. The collected samples of cotton gin dust and almond huller dust were sieved to a known particle size range for testing to determine combustibility potential. Combustibility testing was conducted on the cotton gin dust and almond huller dust samples using the UN test for combustibility suggested in NFPA 652.. This testing indicated that neither the cotton gin dust nor the almond huller dust should be considered combustible dusts (i.e., not a Division 4.1 flammable hazard per 49 CFR 173.124). Copyright© by the American Society of Agricultural Engineers.

Field evaluation of an engineering control for respirable crystalline silica exposures during mortar removal.

PubMed

Collingwood, Scott; Heitbrink, William A

2007-11-01

During mortar removal with a right angle grinder, a building renovation process known as "tuck pointing," worker exposures to respirable crystalline silica can be as high as 5 mg/m(3), 100 times the recommended exposure limit developed by the National Institute for Occupational Safety and Health. To reduce the risk of silicosis among these workers, a vacuum cleaner can be used to exhaust 80 ft(3)/min (2.26 m(3)/min) from a hood mounted on the grinder. Field trials examined the ability of vacuum cleaners to maintain adequate exhaust ventilation rates and measure exposure outcomes when using this engineering control. These field trials involved task-based exposure measurement of respirable dust and crystalline silica exposures during mortar removal. These measurements were compared with published exposure data. Vacuum cleaner airflows were obtained by measuring and digitally logging vacuum cleaner static pressure at the inlet to the vacuum cleaner motor. Static pressures were converted to airflows based on experimentally determined fan curves. In two cases, video exposure monitoring was conducted to study the relationship between worker activities and dust exposure. Worker activities were video taped concurrent with aerosol photometer measurement of dust exposure and vacuum cleaner static pressure as a measure of airflow. During these field trials, respirable crystalline silica exposures for 22 samples had a geometric mean of 0.06 mg/m(3) and a range of less than 0.01 to 0.86 mg/m(3). For three other studies, respirable crystalline silica exposures during mortar removal have a geometric means of 1.1 to 0.35. Although this field study documented noticeably less exposure to crystalline silica, video exposure monitoring found that the local exhaust ventilation provided incomplete dust control due to low exhaust flow rates, certain work practices, and missing mortar. Vacuum cleaner airflow decrease had a range of 3 to 0.4 ft(3)/min (0.08 to 0.01 m(3)/sec(2)) over a range of vacuum cleaners, hose diameters, and hose lengths. To control worker exposure to respirable crystalline silica, local exhaust ventilation needs to be incorporated into a comprehensive silica control program that includes respiratory protection, worker training, and local exhaust ventilation.

Comprehensive Modeling of Superficial Dust Removal via Electrostatic and Dielectrophoretic Forces in Extraterres-trial Exploration Mission

NASA Technical Reports Server (NTRS)

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

2017-01-01

The Electrostatics and Surface Physics Laboratory (ESPL) at NASA Kennedy Space Center has developed a dust mitigation technology that uses electrostatic and dielectrophoretic (DEP) forces to disperse and remove the dust already deposited on surfaces preventing the accumulation of dust particles approaching or already deposited on those surfaces.

Using Engineering Cameras on Mars Landers and Rovers to Retrieve Atmospheric Dust Loading

NASA Astrophysics Data System (ADS)

Wolfe, C. A.; Lemmon, M. T.

2014-12-01

Dust in the Martian atmosphere influences energy deposition, dynamics, and the viability of solar powered exploration vehicles. The Viking, Pathfinder, Spirit, Opportunity, Phoenix, and Curiosity landers and rovers each included the ability to image the Sun with a science camera that included a neutral density filter. Direct images of the Sun provide the ability to measure extinction by dust and ice in the atmosphere. These observations have been used to characterize dust storms, to provide ground truth sites for orbiter-based global measurements of dust loading, and to help monitor solar panel performance. In the cost-constrained environment of Mars exploration, future missions may omit such cameras, as the solar-powered InSight mission has. We seek to provide a robust capability of determining atmospheric opacity from sky images taken with cameras that have not been designed for solar imaging, such as lander and rover engineering cameras. Operational use requires the ability to retrieve optical depth on a timescale useful to mission planning, and with an accuracy and precision sufficient to support both mission planning and validating orbital measurements. We will present a simulation-based assessment of imaging strategies and their error budgets, as well as a validation based on archival engineering camera data.

Recommended features of protocols for long-term ecological monitoring

USGS Publications Warehouse

Oakley, Karen L.; Boudreau, Susan L.; Humphrey, Sioux-Z

2001-01-01

In 1991, the National Park Service (NPS) selected seven parks to serve as prototypes for development of a long-term ecological monitoring program. Denali National Park and Preserve was one of the prototype parks selected. The principal focus of this national program was to detect and document resource changes and to understand the forces driving those changes. One of the major tasks of each prototype park was to develop monitoring protocols. In this paper, we discuss some lessons learned and what we believe to be the most important features of protocols.One of the many lessons we have learned is that monitoring protocols vary greatly in content and format. This variation leads to confusion about what information protocols should contain and how they should be formatted. Problems we have observed in existing protocols include (1) not providing enough detail, (2) omitting critical topics (such as data management), and (3) mixing explanation with instructions. Once written, protocols often sit on the shelf to collect dust, allowing methods changes to occur without being adequately considered, tested, or documented. Because a lengthy and costly research effort is often needed to develop protocols, a vision of what the final product should look like is helpful. Based on our involvement with the prototype monitoring program for Denali (Oakley and Boudreau 2000), we recommend key features of protocols, including a scheme for linking protocols to data in the data management system and for tracking protocol revisions. A protocol system is crucial for producing long-term data sets of known quality that meet program objectives.

Martian Sunsets More Than Just Pretty

NASA Image and Video Library

2004-01-10

This image shows the Sun as it appears on Mars throughout the day. Scientists monitor the dimming of the setting Sun to assess how much dust is in the martian atmosphere. The pictures were taken by the Mars Exploration Rover Spirit panoramic camera.

PERFORMANCE VERIFICATION TEST FOR FIELD-PORTABLE MEASUREMENTS OF LEAD IN DUST

EPA Science Inventory

The US Environmental Protection Agency (EPA) Environmental Technology Verification (ETV) program (www.epa.jzov/etv) conducts performance verification tests of technologies used for the characterization and monitoring of contaminated media. The program exists to provide high-quali...

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.

The Dust Management Project: Characterizing Lunar Environments and Dust, Developing Regolith Mitigation Technology and Simulants

NASA Technical Reports Server (NTRS)

Hyatt, Mark J.; Straka, Sharon A.

2010-01-01

A return to the Moon to extend human presence, pursue scientific activities, use the Moon to prepare for future human missions to Mars, and expand Earth?s economic sphere, will require investment in developing new technologies and capabilities to achieve affordable and sustainable human exploration. From the operational experience gained and lessons learned during the Apollo missions, conducting long-term operations in the lunar environment will be a particular challenge, given the difficulties presented by the unique physical properties and other characteristics of lunar regolith, including dust. The Apollo missions and other lunar explorations have identified significant lunar dust-related problems that will challenge future mission success. 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 and human explorers. The Dust Management Project (DMP) is tasked with the evaluation of lunar dust effects, assessment of the resulting risks, and development of mitigation and management strategies and technologies related to Exploration Systems architectures. To this end, the DMP supports the overall goal of the Exploration Technology Development Program (ETDP) of addressing the relevant high priority technology needs of multiple elements within the Constellation Program (CxP) and sister ETDP projects. Project scope, plans, and accomplishments will be presented.

A new hybrid particle/fluid model for cometary dust

NASA Astrophysics Data System (ADS)

Shou, Y.; Combi, M. R.; Tenishev, V.; Toth, G.; Hansen, K. C.; Huang, Z.; Gombosi, T. I.; Fougere, N.; Rubin, M.

2017-12-01

Cometary dust grains, which originate from comets, are believed to contain clues to the formation and the evolution of comets. They also play an important role in shaping the cometary environment, as they are able to decelerate and heat the gas through collisions, carry charges and interact with the plasma environment, and possibly sublimate gases. Therefore, the loss rate and behavior of dust grains are of interest to scientists. Currently, mainly two types of numerical dust models exist: particle models and fluid models have been developed. Particle models, which keep track of the positions and velocities of all gas and dust particles, allow crossing dust trajectories and a more accurate description of returning dust grains than the fluid model. However, in order to compute the gas drag force, the particle model needs to follow more gas particles than dust particles. A fluid model is usually more computationally efficient and is often used to provide simulations on larger spatial and temporal scales. In this work, a new hybrid model is developed to combine the advantages of both particle and fluid models. In the new approach a fluid model based on the University of Michigan BATSRUS code computes the gas properties, and feeds the gas drag force to the particle model, which is based on the Adaptive Mesh Particle Simulator (AMPS) code, to calculate the motion of dust grains. The coupling is done via the Space Weather Modeling Framework (SWMF). In addition to the capability of simulating the long-term dust phenomena, the model can also designate small active regions on the nucleus for comparison with the temporary fine dust features in observations. With the assistance of the newly developed model, the effect of viewing angles on observed dust jet shapes and the transportation of heavy dust grains from the southern to the northern hemisphere of comet 67P/Churyumov-Gerasimenko will be studied and compared with Rosetta mission images. Preliminary results will be presented. Support from contracts JPL #1266314 and #1266313 from the US Rosetta Project and grant NNX14AG84G from the NASA Planetary Atmospheres Program are gratefully acknowledged.

Dust Storms: Why Are Dust Storms a Concern?

MedlinePlus

... matter , which can be a serious threat to human health if it accumulates in the respiratory system. Dust ... FIND-NLM National Institutes of Health Department of Health & Human Services Developed by Specialized Information Services, Environmental Health ...

Wind-Stress Dust Lifting in a Mars Global Circulation Model: Representation across Resolutions

NASA Astrophysics Data System (ADS)

Chapman, R.; Lewis, S.; Balme, M. R.; Steele, L.

2017-12-01

The formation of Martian dust storms is believed to be driven by dust lifting by near-surface wind stress (NSWS). Accurately representing this dust lifting within Mars Global Circulation Models (MGCMs) is important in order to gain a full understanding of the Martian dust storm cycle. Parameterisations of dust lifting by NSWS exist within several MGCMs; implementations differ but they all follow a similar design, so progress within one model is relevant to the entire field. Few studies have explored in detail how the results of these parameterisations can be affected by changing the horizontal resolution of the model. An accurate parameterisation of dust lifting by NSWS will lift a representative dust mass, reproducing characteristic dust optical depths in the atmosphere. The geographical distribution of the dust lifting by NSWS will also change throughout the year, affecting patterns of dust storm formation and development. Currently, suitable values for dust lifting parameters must be identified at every new model resolution. Resolutions of 5° latitude x 5° longitude are often used to model the Martian climate, as thermal tides and long-term weather patterns can be well represented at this resolution. However, smaller scale phenomena (such as near-surface winds driven by local topography) cannot be accurately depicted at this resolution. We use the LMD-UK MGCM to complete multi-year simulations across multiple model resolutions. Our experiments range from `low' resolution 5° lat x 5° lon to `high' resolution 1° lat x 1° lon. In experiments with fixed, constant lifting parameters, we find that higher resolution simulations lift more dust, but that this trend is asymptotic. At low resolutions, dust lifting increases proportionately with the increase in number of horizontal gridboxes. However, at high resolutions, doubling the number of gridboxes results only in a 30% increase in the total dust mass lifted. Geographical and temporal distributions of dust lifting are investigated, as well as the total dust lifted, in order to assess the optimum parameters for each resolution, and to develop a calibration scheme for this dust lifting across model resolutions. The scheme is verified through comparison with spacecraft observations of dust optical depths and dust storm locations.

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.

Galileo dust data from the jovian system: 2000 to 2003

NASA Astrophysics Data System (ADS)

Krüger, H.; Bindschadler, D.; Dermott, S. F.; Graps, A. L.; Grün, E.; Gustafson, B. A.; Hamilton, D. P.; Hanner, M. S.; Horányi, M.; Kissel, J.; Linkert, D.; Linkert, G.; Mann, I.; McDonnell, J. A. M.; Moissl, R.; Morfill, G. E.; Polanskey, C.; Roy, M.; Schwehm, G.; Srama, R.

2010-06-01

The Galileo spacecraft was the first man-made satellite of Jupiter, orbiting the planet between December 1995 and September 2003. The spacecraft was equipped with a highly sensitive dust detector that monitored the jovian dust environment between approximately 2 and 370 RJ (jovian radius RJ=71 492 km). The Galileo dust detector was a twin of the one flying on board the Ulysses spacecraft. This is the tenth in a series of papers dedicated to presenting Galileo and Ulysses dust data. Here we present data from the Galileo dust instrument for the period January 2000 to September 2003 until Galileo was destroyed in a planned impact with Jupiter. The previous Galileo dust data set contains data of 2883 particles detected during Galileo's interplanetary cruise and 12 978 particles detected in the jovian system between 1996 and 1999. In this paper we report on the data of additional 5389 particles measured between 2000 and the end of the mission in 2003. The majority of the 21 250 particles for which the full set of measured impact parameters (impact time, impact direction, charge rise times, charge amplitudes, etc.) was transmitted to Earth were tiny grains (about 10 nm in radius), most of them originating from Jupiter's innermost Galilean moon Io. They were detected throughout the jovian system and the impact rates frequently exceeded 10 min -1. Surprisingly large impact rates up to 100 min -1 occurred in August/September 2000 when Galileo was far away (≈280RJ) from Jupiter, implying dust ejection rates in excess of 100 kg s -1. This peak in dust emission appears to coincide with strong changes in the release of neutral gas from the Io torus. Strong variability in the Io dust flux was measured on timescales of days to weeks, indicating large variations in the dust release from Io or the Io torus or both on such short timescales. Galileo has detected a large number of bigger micron-sized particles mostly in the region between the Galilean moons. A surprisingly large number of such bigger grains was measured in March 2003 within a four-day interval when Galileo was outside Jupiter's magnetosphere at approximately 350 RJ jovicentric distance. Two passages of Jupiter's gossamer rings in 2002 and 2003 provided the first actual comparison of in-situ dust data from a planetary ring with the results inferred from inverting optical images. Strong electronics degradation of the dust instrument due to the harsh radiation environment of Jupiter led to increased calibration uncertainties of the dust data.

Advances in Dust Detection and Removal for Tokamaks

NASA Astrophysics Data System (ADS)

Campos, A.; Skinner, C. H.; Roquemore, A. L.; Leisure, J. O. V.; Wagner, S.

2008-11-01

Dust diagnostics and removal techniques are vital for the safe operation of next step fusion devices such as ITER. An electrostatic dust detector[1] developed in the laboratory is being applied to NSTX. In the tokamak environment, large particles or fibres can fall on the grid potentially causing a permanent short. We report on the development of a gas puff system that uses helium to clear such particles from the detector. Experiments with varying nozzle designs, backing pressures, puff durations, and exit flow orientations have obtained an optimal configuration that effectively removes particles from a 25 cm^2 area. Dust removal from next step tokamaks will be required to meet regulatory dust limits. A tripolar grid of fine interdigitated traces has been designed that generates an electrostatic travelling wave for conveying dust particles to a ``drain.'' First trials have shown particle motion in optical microscope images. [1] C. H. Skinner et al., J. Nucl. Mater., 376 (2008) 29.

Empirical Models of Zones Protecting Against Coal Dust Explosion

NASA Astrophysics Data System (ADS)

Prostański, Dariusz

2017-09-01

The paper presents predicted use of research' results to specify relations between volume of dust deposition and changes of its concentration in air. These were used to shape zones protecting against coal dust explosion. Methodology of research was presented, including methods of measurement of dust concentration as well as deposition. Measurements were taken in the Brzeszcze Mine within framework of MEZAP, co-financed by The National Centre for Research and Development (NCBR) and performed by the Institute of Mining Technology KOMAG, the Central Mining Institute (GIG) and the Coal Company PLC. The project enables performing of research related to measurements of volume of dust deposition as well as its concentration in air in protective zones in a number of mine workings in the Brzeszcze Mine. Developed model may be supportive tool in form of system located directly in protective zones or as operator tool warning about increasing hazard of coal dust explosion.

Efficiency of Tungsten Dust Collection of Different Types of Dust Particles by Electrostatic Probe

NASA Astrophysics Data System (ADS)

Begrambekov, L. B.; Voityuk, A. N.; Zakharov, A. M.; Bidlevich, O. A.; Vechshev, E. A.; Shigin, P. A.; Vayakis, J.; Walsh, M.

2017-12-01

Formation of dust particles and clusters is observed in almost every modern thermonuclear facility. Accumulation of dust in the next generation thermonuclear installations can dramatically affect the plasma parameters and lead to the accumulation of unacceptably large amounts of tritium. Experiments on collection of dust particles by a model of electrostatic probe developed for collection of metallic dust at ITER are described in the article. Experiments on the generation of tungsten dust consisting of flakes formed during the destruction of tungsten layers formed on the walls of the plasma chamber sputtered from the surface of the tungsten target by plasma ions were conducted. The nature of dust degassing at elevated temperatures and the behavior of dust in an electric field were studied. The results obtained are compared with the results of the experiments with dust consisting of crystal particles of simple geometric shapes. The effectiveness of collection of both types of dust using the model of an electrostatic probe is determined.

Essential Components of a Perimeter Air Monitoring Plan and Worker Protection Program at Sites Involving the Excavation of Naturally Occurring Asbestos (NOA) in California

NASA Astrophysics Data System (ADS)

Zdeb, T. F.

2012-12-01

Preparing a Perimeter Air Monitoring Plan that provides the essential information and methods of evaluation needed to assure that the health of the surrounding community is adequately protected and adapting currently existing Cal/OSHA regulations to be relevant to the protection of workers at sites involving the excavation of Naturally Occurring Asbestos (NOA) is oftentimes challenging in California. Current guidelines regarding what constitutes an effective air monitoring program are often lacking in details regarding what should be sampled and analyzed to characterize a site and what evaluation techniques should be applied to process the results of monitoring, and the current Cal/OSHA asbestos related regulations regarding worker protection are for the most part largely pertinent to the abatement of asbestos in buildings. An overview of the essential components of an effective Baseline and Perimeter Air Monitoring Plan will be presented that includes a brief discussion of the various asbestos types and fiber sizes that may need to be considered, possible approachs for evaluating temporal and spatial variability, review of selected site boundary target concentrations, and consideration of the potential for airborne dust and soil containing asbestos (and other contaminants) to migrate and accumulate offsite eventually contributing to "background creep" --the incremental increase of overall airborne asbestos concentrations in the areas surrounding the site due to the re-entrainment of asbestos from the settled dust and/or transported soil. In addition to the above, the current Cal/OSHA asbestos regulations related to worker protection will be briefly discussed with respect to their relevancy at NOA sites with an overview of the adaptations to the regulations that were developed as a result of some fairly lengthy discussions with representatives of Cal/OSHA. These adaptations include, among other things, defining how regulated areas (asbestos concentrations over 1%) and "provisionally regulated" areas (less than 1%) are established and treated, what variables need to be considered when attempting to complete a personal exposure assessment, Cal/OSHA Permissible Exposure Limits (PELs) versus site specific permissible exposure limits, allowable work practices, and the qualifications of personnel performing the sampling and analyses of data.

An Extensive Study on Dynamical aspects of Dust Storm over the United Arab Emirates during 18-20 March 2012

NASA Astrophysics Data System (ADS)

Basha, Ghouse; Phanikumar, Devulapalli V.; Ouarda, Taha B. M. J.

2015-04-01

On 18 March 2012, a super dust storm event occurred over Middle East (ME) and lasted for several hours. Following to this, another dust storm occurred on early morning of 20 March 2012 with almost higher intensity. Both these storms reduced the horizontal visibility to few hundreds of meters and represented as one of the most intense and long duration dust storms over United Arab Emirates (UAE) in recent times. These storms also reduced the air quality in most parts of the ME implying the shutdown of Airports, schools and hundreds of people were hospitalized with respirational problems. In the context of the above, we have made a detailed study on the dynamical processes leading to triggering of dust storm over UAE and neighboring regions. We have also analyzed its impact on surface, and vertical profiles of background parameters and aerosols during the dust storm period by using ground-based, space borne, dust forecasting model, and reanalysis data sets. The synoptic and dynamic conditions responsible for the occurrence of the dust storm are discussed extensively by using European Centre for Medium-Range Weather Forecasts (ECMWF) ERA interim reanalysis data sets. The Impact of dust storm on surface and upper air radiosonde measurements and aerosol optical properties are also investigated before, during and after the dust storm event. During the dust storm, surface temperature decreased by 15oC when compared to before and after the event. PM10 values significantly increased maximum of about 1600µg/m3. Spatial variation of Aerosol Optical Depth (AOD) from Moderate-resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI) aerosol index (AI) exhibited very high values during the event and source region can be identified of dust transport to our region with this figure. The total attenuated backscatter at 550nm from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite shows the vertical extent of dust up to 8km. The dynamics of this event is related to coupling of subtropical jet and polar jet over the Saudi Arabia region, which leads to massive dust storm generation and dust transport through Rub-Al-Khali, and Persian Gulf over the UAE region. AOD from ground based measurements showed fourfold increase from 0.2 to 1.8 during the event implying an atmospheric forcing of ~ 150 Wm-2. In addition, vertical profile of heating rate showed heating of ~1.5 K/day at 3-4 km during the event. In the view of the above, the present event is discussed in the light of current understanding of dust storm aerosol optical and physical processes and associated dynamics over UAE region.

Summary of the development of a signature for detection of residual dust from collapse of the World Trade Center buildings

PubMed Central

Lowers, Heather A; Meeker, Gregory P; Lioy, Paul J; Lippmann, Morton

2014-01-01

The collapse of the World Trade Center (WTC) towers on September 11, 2001, caused lower Manhattan and adjacent areas to be covered in millimeters to centimeters of dust. WTC dust penetrated into indoor spaces, and public health concerns remain regarding exposure to possible residual dust in the affected areas. The goal of the studies outlined in this review was to determine which, if any, components of the bulk WTC dust are sufficiently above typical background dust levels in New York City to develop an analytical method to screen for the component(s). Components of the <150-µm-size fraction of the dust are gypsum, phases compatible with crushed concrete, man-made vitreous fibers (MMVFs), silica, lead, chrysotile asbestos, and other materials. Slag wool was the most common WTC MMVF, whereas soda-lime glass and rock wool were minor to trace constituents. Most background samples also contained gypsum, phases compatible with concrete, and MMVF. However, the proportions of the various MMVF in background samples are typically unlike those characteristic of bulk WTC dust. Results indicate that slag wool can be used as a signature marker to identify areas that contain potential residual WTC dust contamination at concentrations that are less than average background levels for the material. PMID:18478046

Radon Monitoring in Army Stand-Alone Housing Units

DTIC Science & Technology

1990-04-01

greater damage to tissues. The internal exposures to alpha radiation resulting from inhalation of radioactive radon daughters (adsorbed onto airborne...appropriate detector, the monitor can measure all or some of the radon daughters adsorbed onto airborne, respirable dust particles. As with the 3...input to the cell is equipped with a 0.8-rim micropore filter that3removes any solid radon daughters from the air stream. Alpha I 26 Final Report, April

Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site during SAPUSS - diurnal variations and PMF receptor modelling

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Amato, F.; Karanasiou, A.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.

2013-04-01

Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter < 2.5 μm) resolved aerosol samples analysed by Particle Induced X-ray Emission (PIXE) measurements. In the Marie Curie European Union framework of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies), the approach used is the simultaneous sampling at two monitoring sites in Barcelona (Spain) during September-October 2010: an urban background site (UB) and a street canyon traffic road site (RS). Elements related to primary non-exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (regional sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non-exhaust brake dust (Fe-Cu) - 7%), and three types of industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%, percentages presented are average source contributions to the total elemental mass measured). The validity of the PMF solution of the PIXE data is supported by very good correlations with external single particle mass spectrometry measurements. Some important conclusions can be drawn about the PM2.5 mass fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2) by contrast, local industrial aerosol plumes associated with shipping oil combustion and smelters activities have a higher impact on the more ventilated UB site; (3) a unique source of Pb-Cl (associated with combustion emissions) is found to be the major (82%) source of fine Cl in the urban agglomerate; (4) the mean diurnal variation of PM2.5 primary traffic non-exhaust brake dust (Fe-Cu) suggests that this source is mainly emitted and not resuspended, whereas PM2.5 urban dust (Ca) is found mainly resuspended by both traffic vortex and sea breeze; (5) urban dust (Ca) is found the aerosol source most affected by land wetness, reduced by a factor of eight during rainy days and suggesting that wet roads may be a solution for reducing urban dust concentrations.

Distribution of pesticides in dust particles in urban environments.

PubMed

Richards, Jaben; Reif, Ruben; Luo, Yuzhuo; Gan, Jay

2016-07-01

In regions with a mild climate, pesticides are often used around homes for pest control. Recent monitoring studies have linked pesticide use in residential areas to aquatic toxicity in urban surface water ecosystems, and suggested dust particles on paved surfaces as an important source of pesticides. To test the hypothesis that dust on hard surfaces is a significant source of pesticides, we evaluated spatial and temporal patterns of current-use insecticides in Southern California, and further explored their distribution as a function of particle sizes. Pyrethroid insecticides were detected in dust from the driveway, curb gutter and street at 53.5-94.8%, with median concentrations of 1-46 ng g(-1). Pyrethroid residues were uniformly distributed in areas adjacent to a house, suggesting significant redistribution. The total levels of pyrethroids in dust significantly (p < 0.01) decreased from October to February, suggesting rainfalls as a major mechanism to move pesticide residues offsite. Fipronil as well as its degradation products, were detected at 50.6-75.5%, and spatial and temporal patterns of fipronil residues suggested rapid transformations of fipronil to its biologically active intermediates. Moreover, pyrethroids were found to be enriched in fine particles that have a higher mobility in runoff than coarse particles. Results from this study highlight the widespread occurrence of pesticides in outdoor dust around homes and the potential contribution to downstream surface water contamination via rain-induced runoff. Copyright © 2016 Elsevier Ltd. All rights reserved.

What is the sensitivity of the mineral dust cycle at the regional scale to surface wind speed? First insights from the DRUMS project.

NASA Astrophysics Data System (ADS)

Bouet, Christel; Siour, Guillaume; Poulet, David; Bergametti, Gilles; Laurent, Benoit; Brocheton, Fabien; Forêt, Gilles; Xu, Yiwen; Marticorena, Béatrice

2017-04-01

Modelling of the mineral dust cycle is still a challenging issue both at the global and regional scales: during the last decade, several exercises of model intercomparison highlighted the wide variability of the existing dust models to estimate dust emission fluxes and atmospheric load at both scales. For instance, within the framework of the international AEROCOM Project (http://aerocom.met.no/), 15 different global dust models provide a range of possible dust emission fluxes from 400 to 2200 Tg yr-1 for North Africa and from 26 to 526 Tg yr-1 for the Middle East, i.e. still a factor of 5 and 20 respectively (Huneeus et al., 2011). Whatever the scale, a critical aspect for any dust model is the sensitivity to the meteorological fields used to compute dust emission fluxes (external forcing or simulated by the coupled meteorological or climatic model). Indeed, the intensity of dust emission varies as a power 3 of the surface wind speed, and the number of dust emission events is the number of times the surface wind speed exceeds the wind erosion threshold. As a result, the simulations of dust emissions are extremely sensitive to the way the surface wind speeds are accounted for both in global and regional models. In this context, the aim of the DRUMS (DeseRt dUst Modeling: performance and Sensitivity evaluation) project was to investigate the sensitivity of a regional dust model (CHIMERE) to this parameter. This sensitivity study was conducted for 3 years from 2006 to 2008 over the North of Africa (45°N-0°N; 45°W-55°E), where dust emissions are the most intense. Emission fluxes can be simulated there with the most relevant data set of surface properties controlling dust emissions and accounting for the heterogeneity of land surfaces (surface roughness, soil size distribution and texture) of desert regions (Laurent et al., 2008). Meteorological products (forecasts and re-analysis) provided by the most recognized international meteorological centres (US NCEP and ECMWF), and thus the most widely used for the simulations of the mineral dust cycle, were tested. In addition, the benefit provided by the use of the WRF model to downscale the meteorological forcing was evaluated. The estimation of the performance of the CHIMERE model forced by the different meteorological fields was conducted using a unique validation data set compiled during the project by analysing and evaluating (i) the large number of experimental data resulting from the AMMA (African Monsoon Multidisciplinary Analysis) field campaigns, (ii) long-term aerosol monitoring over West Africa (Sahelian Dust Transect) and downwind the Sahara/Sahel region (AERONET), and (iii) recent satellite aerosol products (SeaWIFS AOD). This dataset allowed to validate the main characteristics of the dust cycle (emission, transport, and deposit).

Mimicking Mars: A vacuum simulation chamber for testing environmental instrumentation for Mars exploration

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

Sobrado, J. M., E-mail: sobradovj@inta.es; Martín-Soler, J.; Martín-Gago, J. A.

We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10{sup −6} mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source andmore » its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.« less

Space Environmental Testing of the Electrodynamic Dust Shield Technology

NASA Technical Reports Server (NTRS)

Calle, Carlos I.; Mackey, P. J.; Hogue, M. D.; Johansen, M .R.; Yim, H.; Delaune, P. B.; Clements, J. S.

2013-01-01

NASA's exploration missions to Mars and the moon may be jeopardized by dust that will adhere to surfaces of (a) Optical systems, viewports and solar panels, (b) Thermal radiators, (c) Instrumentation, and (d) Spacesuits. We have developed an active dust mitigation technology, the Electrodynamic Dust Shield, a multilayer coating that can remove dust and also prevents its accumulation Extensive testing in simulated laboratory environments and on a reduced gravity flight shows that high dust removal performance can be achieved Long duration exposure to the space environment as part of the MISSE-X payload will validate the technology for lunar missions.

Coal dust contiguity-induced changes in the concentration of TNF- and NF- B p65 on the ocular surface

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

Sun, Z.Y.; Hong, J.; Liu, Z.Y.

2009-07-01

To observe the influence of coal dust on ocular surface of coal miners and rabbits with coal dust contiguity on expression TNF- and NF- Bp65 and dry eye occurrence. Expression TNF- and NF- Bp65 in ocular surface were determined. Results showed tear production, BUT and lysozyme decreased for coal miners and rabbits with coal dust contiguity. Coal dust exposure was linked to development of xerophthalmia, and induced a higher expression of NF- B p65 and TNF- perhaps as a mechanism to resist coal dust ocular surface injury.

Analysis of land surface and synoptic conditions during dust storm events in the Middle East via a new high resolution inventory of mineral dust derived from SEVIRI.

NASA Astrophysics Data System (ADS)

Hennen, Mark

2017-04-01

This paper provides the most up-to-date dust climatology for the Middle East, presenting a new high resolution inventory of over 27,000 dust emission events observed over the Middle East in 2006 - 2013. The inventory was derived from the dust RGB product of the Spinning Enhanced Visual and InfraRed Imager (SEVIRI) on-board Meteosat's second generation satellite (MSG). Mineral dust emissions were derived from visual inspection of the SEVIRI scenes which have 4-5 km2 spatial and 15-minute temporal resolution. The location of every emission event was recorded in a database, along with time and trajectory of dust movement. This is an improvement on previous studies, which derive dust source areas from the daily observations of Aerosol Optical Depth whose maxima do not necessarily coincide with sources of emissions and produces more accurate information on the location of the key dust sources in the region. Results showed that dust sources are constrained to relatively small areas, with 21% of dust emission generated from just 0.9% of total surface area of the Middle East, mainly from eight source regions including the Tigris-Euphrates flood plains of Iraq and Syria, Western and Northern Saudi Arabia and the Sistan Basin in Eastern Iran. The Tigris-Euphrates flood plain was the most active dust region, producing 41% of all dust events with a peak activity in 2009. The southern areas of the Arabian Peninsula recorded very few dust emission observations, in contrast to many previous studies which do not use such high temporal resolution data. The activation and frequency of dust emissions are characterised by strong seasonality developing in response to specific synoptic conditions. To characterise synoptic conditions conducive to the development of dust storms, dust days' emission thresholds, based on number of dust emission events per day / per region and specific to each of the eight main dust emitting regions, were determined. ERA Interim reanalysis data were used to characterise synoptic conditions on the identified dust days. With vegetation cover dictating the ability for surface areas to deflate, Normalised Difference Vegetation Index (NDVI) data was acquired from the Moderate Resolution Imaging Spectrodiometer (MODIS) (MOD13A2) 1km database and correlated with dust emission frequency data in the region of greatest dust activity, the Tigris and Euphrates flood plain in Iraq and Syria.

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.

IRAC Monitoring of the Late Heavy Comet Bombardment in the eta Corvi System

NASA Astrophysics Data System (ADS)

Marengo, Massimo; Lisse, Carey; Stapelfeldt, Karl; Hulsebus, Alan

2014-12-01

The nearby sun-like star eta Corvi (F2V, d=18 pc, age =1.2 Gyr) has long been known to possess a bright, dusty Kuiper Belt that has now been resolved with Herschel PACS. A warm inner dust belt indicated by an IRAS 12 micron excess and has recently been resolved as a 3-AU scale structure by VLT observations. In 2012 Lisse et al. further characterized this warm dust using Spitzer IRS, identifying the signatures of ice, organics and silicate dust in this system's Terrestrial Habitability Zone (THZ). The system appears to be undergoing a Late Heavy Bombardment (LHB), delivering primitive, water- and organic-rich material from the Kuiper Belt to the THZ, at roughly the same relative age as the solar system's LHB. Our data also showed an upturn in the excess flux shortwards of 6 micron ? evidence for a surprisingly large amount of icy dust scattering in the inner system (fscat/fstar ~ 1.0%). This results is corroborated by our recent 2-5 micron NASA/IRTF SpeX spectroscopy. In 2012 we have obtained Spitzer/IRAC photometric data for the system, detecting the disk at 3.6 and 4.5 micron in two separate epochs, followed by a third epoch in 2013. We now propose to continue our photometric monitoring with 15 additional visits to be scheduled within cycle 11, in order to extend our temporal coverage to 4 years on a variety of timescales ranging from days, to weeks, to months. The proposed campaign will allow us to test the two competing hypothesis for the origin of the warm disk: (1) single collison event leading to the breakup of a large Kuiper Belt object in the system or (2) continual raining of small comets scattered towards the inner system.

Polycyclic aromatic hydrocarbon emission profiles and removal efficiency by electrostatic precipitator and wetfine scrubber in an iron ore sintering plant

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

Ettore Guerriero; Antonina Lutri; Rosanna Mabilia

2008-11-15

A monitoring campaign of polychlorinated dibenzo-p-dioxins and dibenzofurans, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyl was carried out in an Italian iron ore sintering plant by sampling the combustion gases at the electrostatic precipitator (ESP) outlet, at the Wetfine scrubber (WS) outlet, and by collecting the ESP dust. Few data are available on these micropollutants produced in iron ore sintering plants, particularly from Italian plants. This study investigates the PAH emission profiles and the removal efficiency of ESPs and WS. PAHs were determined at the stack, ESP outlet flue gases, and in ESP dust to characterize the emission profiles and themore » performance of the ESP and the WS for reducing PAH emission. The 11 PAHs monitored are listed in the Italian legislative decree 152/2006. The mean total PAH sum concentration in the stack flue gases is 3.96 {mu}g/N m{sup 3}, in ESP outlet flue gases is 9.73 {mu}g/N m{sup 3}, and in ESP dust is 0.53 {mu}g/g. Regarding the emission profiles, the most abundant compound is benzo(b)fluoranthene, which has a relative low BaP toxic equivalency factors (TEF) value, followed by dibenzo(a,l)pyrene, which has a very high BaP(TEF) value. The emission profiles in ESP dust and in the flue gases after the ESP show some changes, whereas the fingerprint in ESP and stack flue gases is very similar. The removal efficiency of the ESP and of WS on the total PAH concentration is 5.2 and 59.5%, respectively. 2 figs., 5 tabs.« less

Effective Utilization of Satellite Observations for Assessing Transnational Impact of Disasters

NASA Astrophysics Data System (ADS)

Alozie, J. E.; Anuforom, A. C.

2014-12-01

General meteorological observations sources for the surface, upper air and outer space are conducted using different technological equipment and instruments that meet international standards prescribed and approved by the United Nations organizations such as the International Civil Aviation Organization (ICAO) and the World Meteorological Organization (WMO). Satellite weather observations are critical for effective monitoring of the developments, propagations and disseminations of cold clouds and their expected adverse weather conditions as they move across national and transnational boundaries. The Nigerian Meteorological Agency (NiMet) which is the national weather service provider for Nigeria, utilizes an array of satellite products obtained from mainly the European Meteorological Satellite (EUMETSAT) for its routine weather and climate monitoring and forecasts. Overtime, NiMet has used weather workstations such as MSG, SYNERGIE and now PUMA for accessing satellite products such as RGB, Infra-red, Water vapour and the Multi-sensor Precipitation Estimate (MPE) obtained at near real-time periods. The satellite imageries find extensive applications in the delivery of early warning of raising of severe weather conditions such as dust storm and dust haze during the harmattan season (November - February); and thunderstorm accompanied by severe lightning and destructive strong winds. The paper will showcase some special cases of the tracking of squall lines and issuance of weather alerts through the media. The good result is that there was limited damage to infrastructure and no loss of life from the flash floods caused by the heavy rainfall from the squally thunderstorm.

Direct Radiative Effect of Mineral Dust on the Development of African Easterly Wave in Late Summer, 2003-2007

NASA Technical Reports Server (NTRS)

Ma, Po-Lun; Zhang, Kai; Shi, Jainn Jong; Matsui, Toshihisa; Arking, Albert

2012-01-01

Episodic events of both Saharan dust outbreaks and African Easterly Waves (AEWs) are observed to move westward over the eastern tropical Atlantic Ocean. The relationship between the warm, dry, and dusty Saharan Air Layer (SAL) on the nearby storms has been the subject of considerable debate. In this study, the Weather Research and Forecasting (WRF) model is used to investigate the radiative effect of dust on the development of AEWs during August and September, the months of maximum tropical cyclone activity, in years 2003-2007. The simulations show that dust radiative forcing enhances the convective instability of the environment. As a result, most AEWs intensify in the presence of a dust layer. The Lorenz energy cycle analysis reveals that the dust radiative forcing enhances the condensational heating, which elevates the zonal and eddy available potential energy. In turn, available potential energy is effectively converted to eddy kinetic energy, in which local convective overturning plays the primary role. The magnitude of the intensification effect depends on the initial environmental conditions, including moisture, baroclinity, and the depth of the boundary layer. We conclude that dust radiative forcing, albeit small, serves as a catalyst to promote local convection that facilitates AEW development.

Direct Radiative Effect of Mineral Dust on the Development of African Easterly Waves in Late Summer, 2003-07

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

Ma, Po-Lun; Zhang, Kai; Shi, Jainn Jong

2012-12-19

Episodic events of both Saharan dust outbreaks and African easterly waves (AEWs) are observed to move westward over the eastern tropical Atlantic Ocean. The relationship between the warm, dry, and dusty Saharan air layer on the nearby storms has been the subject of considerable debate. In this study, the Weather Research and Forecasting model is used to investigate the radiative effect of dust on the development of AEWs during August and September, the months of maximumtropical cyclone activity, in years 2003–07. The simulations show that dust radiative forcing enhances the convective instability of the environment. As a result, mostAEWsintensify inmore » the presence of a dust layer. The Lorenz energy cycle analysis reveals that the dust radiative forcing enhances the condensational heating, which elevates the zonal and eddy available potential energy. In turn, available potential energy is effectively converted to eddy kinetic energy, in which local convective overturning plays the primary role. The magnitude of the intensification effect depends on the initial environmental conditions, including moisture, baroclinity, and the depth of the boundary layer. The authors conclude that dust radiative forcing, albeit small, serves as a catalyst to promote local convection that facilitates AEW development.« less

Lunar Dust Monitor to BE Onboard the Next Japanese Lunar Mission SELENE-2

NASA Astrophysics Data System (ADS)

Ohashi, Hideo

The next Japanese lunar mission SELENE-2, after a successful mission Kaguya (a project named SELENE), is planned to be launched in mid 2010s and is consisted of a lander, a rover, and an orbiter, as a transmitting satellite to the earth. A dust particle detector LDM (Lunar Dust Monitor) is proposed to be onboard the orbiter. The LDM is an impact ionization detector with dimensions 25 cm × 25 cm × 30 cm, and it has a sensor part (LDM-S, upper module) and an electronics part (LDM-E, lower module). The LDM-S has a large target (gold-plated Al) of 400 cm2 , to which a high voltage of +500 V is applied. The LDM-S also has two meshed grids parallel to the target. The grids are etched stainless steel with 90% transparency: the inner grid is 2 cm apart from the target and the outer grid is 15 cm from the target. When a charged dust particle passes through the outer and inner grids, it induces an electric signal on the grids separated by a certain time interval, determined by the velocity of the incident particle and the distance between the outer and inner grids. By measuring the time interval, we can calculate the velocity of the particle, with the ambiguity of its trajectory to the target. When the incident particle impacts on the target, plasma gas of electrons and ions is generated. The electrons of the plasma are collected by the target and the ions are accelerated toward the inner grids as a result of the electric field. Some of the ions drift through the inner grid and reach the outer grid. The outer and inner grids and the target are connected to charge-sensitive amplifiers, which convert charge signals induced by the electrons and ions to voltage signals that are fed to a following flash ADC driven with 10 MHz. The waveforms from two grids and the target can be stored and be sent back to ground for data analysis. We can deduce the mass and velocity information of the incident dust particle from the recorded waveforms. The orbiter of SELENE-2 is planned to be in operation for one year or more, and the LDM will observe circumlunar dust for as long as possible. We report scientific importance of dust measurement around the Moon, and current status of LDM in this conference.

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

The Lunar Atmosphere and Dust Environment Explorer (LADEE): Initial Science Results

NASA Technical Reports Server (NTRS)

Elphic, R. C.; Hine, B.; Delory, G. T.; Salute, J. S.; Noble, S.; Colaprete, A.; Horanyi, M.; Mahaffy, P.

2014-01-01

On September 6, 2013, a near-perfect launch of the first Minotaur V rocket successfully carried NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) into a high-eccentricity geocentric orbit. LADEE arrived at the Moon on October 6, 2013, dur-ing the government shutdown. The spacecraft impact-ed the lunar surface on April 18, 2014, following a completely successful mission. LADEE's science objectives were twofold: (1) De-termine the composition and variability of the lunar atmosphere; (2) Characterize the lunar exospheric dust environment, and its variability. The LADEE science payload consisted of the Lunar Dust Experiment (LDEX), which sensed dust impacts in situ, for parti-cles between 100 nm and 5 micrometers; a neutral mass spectrometer (NMS), which sampled lunar exo-spheric gases in situ, over the 2-150 Dalton mass range; an ultraviolet/visible spectrometer (UVS) ac-quired spectra of atmospheric emissions and scattered light from tenuous dust, spanning a 250-800 nm wave-length range. UVS also performed dust extinction measurements via a separate solar viewer optic. The following are preliminary results for the lunar exosphere: (1) The helium exosphere of the Moon, first observed during Apollo, is clearly dominated by the delivery of solar wind He++. (2) Neon 20 is clearly seen as an important constituent of the exosphere. (3) Argon 40, also observed during Apollo and arising from interior outgassing, exhibits variations related to surface temperature-driven condensation and release, and is also enhanced over specific selenographic longi-tudes. (4) The sodium abundance varies with both lu-nar phase and with meteoroid influx, implicating both solar wind sputtering and impact vaporization process-es. (5) Potassium was also routinely monitored and exhibits some of the same properties as sodium. (6) Other candidate species were seen by both NMS and UVS, and await confirmation. Dust measurements have revealed a persistent "shroud" of small dust particles between 0.7 and sev-eral micrometers in size, present over the pre-dawn and morning sector of the Moon. This tenuous dust exosphere, with densities of approximately 10(exp -5) m(exp -3), appears to be sustained by the ejecta of micrometeoroid impacts.

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.

40 CFR 63.1544 - Standards for fugitive dust sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... associated air pollution control equipment and monitoring equipment, in a manner consistent with safety and good air pollution control practices for minimizing emissions. Determination of whether such operation.... 63.1544 Section 63.1544 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...