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Sample records for airborne dust levels

  1. Airborne manganese as dust vs. fume determining blood levels in workers at a manganese alloy production plant

    PubMed Central

    Park, Robert M.; Baldwin, Mary; Bouchard, Maryse F.; Mergler, Donna

    2015-01-01

    The appropriate exposure metrics for characterizing manganese (Mn) exposure associated with neurobehavioral effects have not been established. Blood levels of Mn (B-Mn) provide a potentially important intermediate marker of Mn airborne exposures. Using data from a study of a population of silicon- and ferro-manganese alloy production workers employed between 1973 and 1991, B-Mn levels were modeled in relation to prior Mn exposure using detailed work histories and estimated respirable Mn concentrations from air-sampling records. Despite wide variation in exposure levels estimated for individual jobs, duration of employment (exposure) was itself a strong predictor of B-Mn levels and strongest when an 80-day half-life was applied to contributions over time (t = 6.95, 7.44, respectively; p < 10 −5). Partitioning exposure concentrations based on process origin into two categories: (1) “large” respirable particulate (Mn-LRP) derived mainly from mechanically generated dust, and (2) “small” respirable particulate (Mn-SRP) primarily electric furnace condensation fume, revealed that B-Mn levels largely track the small, fume exposures. With a half-life of 65 days applied in a model with cumulative exposure terms for both Mn-LRP (t = −0.16, p = 0.87) and Mn-SRP (t = 6.45, p < 10 −5), the contribution of the large-size fraction contribution was negligible. Constructing metrics based on the square root of SRP exposure concentrations produced a better model fit (t = 7.87 vs. 7.44, R2 = 0.2333 vs. 0.2157). In a model containing both duration (t = 0.79, p = 0.43) and (square root) fume (t = 2.47, p = 0.01) metrics, the duration term was a weak contributor. Furnace-derived, small respirable Mn particulate appears to be the primary contributor to B-Mn levels, with a dose-rate dependence in a population chronically exposed to Mn, with air-concentrations declining in recent years. These observations may reflect the presence of homeostatic control of Mn levels in the blood

  2. Airborne manganese as dust vs. fume determining blood levels in workers at a manganese alloy production plant.

    PubMed

    Park, Robert M; Baldwin, Mary; Bouchard, Maryse F; Mergler, Donna

    2014-12-01

    The appropriate exposure metrics for characterizing manganese (Mn) exposure associated with neurobehavioral effects have not been established. Blood levels of Mn (B-Mn) provide a potentially important intermediate marker of Mn airborne exposures. Using data from a study of a population of silicon- and ferro-manganese alloy production workers employed between 1973 and 1991, B-Mn levels were modeled in relation to prior Mn exposure using detailed work histories and estimated respirable Mn concentrations from air-sampling records. Despite wide variation in exposure levels estimated for individual jobs, duration of employment (exposure) was itself a strong predictor of B-Mn levels and strongest when an 80-day half-life was applied to contributions over time (t=6.95, 7.44, respectively; p<10(-5)). Partitioning exposure concentrations based on process origin into two categories: (1) "large" respirable particulate (Mn-LRP) derived mainly from mechanically generated dust, and (2) "small" respirable particulate (Mn-SRP) primarily electric furnace condensation fume, revealed that B-Mn levels largely track the small, fume exposures. With a half-life of 65 days applied in a model with cumulative exposure terms for both Mn-LRP (t=-0.16, p=0.87) and Mn-SRP (t=6.45, p<10(-5)), the contribution of the large-size fraction contribution was negligible. Constructing metrics based on the square root of SRP exposure concentrations produced a better model fit (t=7.87 vs. 7.44, R(2)=0.2333 vs. 0.2157). In a model containing both duration (t=0.79, p=0.43) and (square root) fume (t=2.47, p=0.01) metrics, the duration term was a weak contributor. Furnace-derived, small respirable Mn particulate appears to be the primary contributor to B-Mn levels, with a dose-rate dependence in a population chronically exposed to Mn, with air-concentrations declining in recent years. These observations may reflect the presence of homeostatic control of Mn levels in the blood and other body tissues and be

  3. Airborne Dust in Space Vehicles and Habitats

    NASA Technical Reports Server (NTRS)

    James, John

    2006-01-01

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

  4. Airborne Dust Models in Valley Fever Research

    NASA Astrophysics Data System (ADS)

    Sprigg, W. A.; Galgiani, J. N.; Vujadinovic, M.; Pejanovic, G.; Vukovic, A. J.; Prasad, A. K.; Djurdjevic, V.; Nickovic, S.

    2011-12-01

    Dust storms (haboobs) struck Phoenix, Arizona, in 2011 on July 5th and again on July 18th. One potential consequence: an estimated 3,600 new cases of Valley Fever in Maricopa County from the first storm alone. The fungi, Coccidioides immitis, the cause of the respiratory infection, Valley Fever, lives in the dry desert soils of the American southwest and southward through Mexico, Central America and South America. The fungi become part of the dust storm and, a few weeks after inhalation, symptoms of Valley Fever may appear, including pneumonia-like illness, rashes, and severe fatigue. Some fatalities occur. Our airborne dust forecast system predicted the timing and extent of the storm, as it has done with other, often different, dust events. Atmosphere/land surface models can be part of public health services to reduce risk of Valley Fever and exacerbation of other respiratory and cardiovascular illness.

  5. β-(1,3)-Glucan Exposure Assessment by Passive Airborne Dust Sampling and New Sensitive Immunoassays▿

    PubMed Central

    Noss, Ilka; Wouters, Inge M.; Bezemer, Gillina; Metwali, Nervana; Sander, Ingrid; Raulf-Heimsoth, Monika; Heederik, Dick J. J.; Thorne, Peter S.; Doekes, Gert

    2010-01-01

    Associations between house dust-associated β-(1,3)-glucan exposure and airway inflammatory reactions have been reported, while such exposures in early childhood have been suggested to protect against asthma and wheezing. Most epidemiological studies have used reservoir dust samples and an inhibition enzyme immunoassay (EIA) for β-(1,3)-glucan exposure assessment. The objective of this study was to develop inexpensive but highly sensitive enzyme immunoassays to measure airborne β-(1,3)-glucans in low-exposure environments, like homes. Specificities of available anti-β-(1,3)-glucan antibodies were defined by direct and inhibition experiments. Three suitable antibody combinations were selected for sandwich EIAs. β-(1,3)-Glucans in passive airborne dust collected with an electrostatic dust fall collector (EDC) and floor dust from seven homes were measured with the three EIAs. Floor dust samples were additionally analyzed in the inhibition EIA. The sandwich EIAs were sensitive enough for airborne glucan measurement and showed different specificities for commercial glucans, while the β-(1,3)-glucan levels in house dust samples correlated strongly. The feasibility of measuring glucans in airborne dust with the recently introduced EDC method was further investigated by selecting the most suitable of the three EIAs to measure and compare β-(1,3)-glucan levels in the EDC and in floor and actively collected airborne dust samples of the previously performed EDC validation study. The EDC β-(1,3)-glucan levels correlated moderately with β-(1,3)-glucans in actively collected airborne dust and floor dust samples, while the glucan levels in the airborne dust and floor dust samples did not correlate. The combination of the newly developed β-(1,3)-glucan sandwich EIA with EDC sampling now allows assessment in large-scale population studies of exposure to airborne β-(1,3)-glucans in homes or other low-exposure environments. PMID:20038709

  6. Migration of Contaminated Soil and Airborne Particulates to Indoor Dust

    PubMed Central

    Layton, David W.; Beamer, Paloma I.

    2009-01-01

    We have developed a modeling and measurement framework for assessing transport of contaminated soils and airborne particulates into a residence, their subsequent distribution indoors via resuspension and deposition processes, and removal by cleaning and building exhalation of suspended particles. The model explicitly accounts for the formation of house dust as a mixture of organic matter (OM) such as shed skin cells and organic fibers, soil tracked-in on footwear, and particulate matter (PM) derived from the infiltration of outdoor air. We derived formulas for use with measurements of inorganic contaminants, crustal tracers, OM, and PM to quantify selected transport parameters. Application of the model to residences in the U.S. Midwest indicates that As in ambient air can account for nearly 60% of the As input to floor dust, with soil track-in representing the remainder. Historic data on Pb contamination in Sacramento, CA, was used to reconstruct sources of Pb in indoor dust, showing that airborne Pb was likely the dominant source in the early 1980s. However, as airborne Pb levels declined due to the phase out of leaded gasoline, soil resuspension and track-in eventually became the primary sources of Pb in house dust. PMID:19924944

  7. 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

  8. Immune Alterations in Rats Exposed to Airborne Lunar Dust

    NASA Technical Reports Server (NTRS)

    Crucian, Brian; Quiriarte, Heather; Nelman, Mayra; Lam, Chiu-wing; James, John T.; Sams, Clarence

    2014-01-01

    The lunar surface is covered by a layer of fine, reactive dust. Very little is known regarding the toxicity of lunar dust on human physiology. This study assessed the toxicity of airborne lunar dust exposure in rats on pulmonary and systemic immune parameters.

  9. Sampling and analysis method for measuring airborne coal dust mass in mixtures with limestone (rock) dust.

    PubMed

    Barone, T L; Patts, J R; Janisko, S J; Colinet, J F; Patts, L D; Beck, T W; Mischler, S E

    2016-01-01

    Airborne coal dust mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone dust, which is an incombustible dust applied to prevent the propagation of dust explosions. To accurately measure the coal portion of this mixed airborne dust, the National Institute for Occupational Safety and Health (NIOSH) developed a sampling and analysis protocol that used a stainless steel cassette adapted with an isokinetic inlet and the low temperature ashing (LTA) analytical method. The Mine Safety and Health Administration (MSHA) routinely utilizes this LTA method to quantify the incombustible content of bulk dust samples collected from the roof, floor, and ribs of mining entries. The use of the stainless steel cassette with isokinetic inlet allowed NIOSH to adopt the LTA method for the analysis of airborne dust samples. Mixtures of known coal and limestone dust masses were prepared in the laboratory, loaded into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal dust mass measurements differed from predicted values by an average of 0.5%, 0.2%, and 0.1% for samples containing 20%, 91%, and 95% limestone dust, respectively. The ability of this method to accurately quantify the laboratory samples confirmed the validity of this method and allowed NIOSH to successfully measure the coal fraction of airborne dust samples collected in an underground coal mine. PMID:26618374

  10. Effects of airborne dust collected from Kuwait on human erythrocytes

    SciTech Connect

    Siddiqui, S.M.; Khan, S.A.; Ahmad, S.; Beg, M.U.

    1992-01-01

    Air borne dust as deposited on air conditioner's filter was collected from most polluted regions of Kuwait and for comparison also from Dubai. Kuwait dust samples were found to contain high concentrations of Ni, Mn and Pb and a number of organic compounds different from the oil samples collected from the oil pool in the oil fields. Toxicity evaluation against human erythrocytes showed strong hemolytic nature of the dust. Treatment of erythrocytes with the dust exhibited peroxidative damage of the membrane. The dust collected from Dubai was innocuous. The present data suggest that erythrocyte damaging potential of the dust can be used as a marker of toxicity and provide information about the dissipation of toxic factors from airborne dust with time. 15 refs., 2 figs., 3 tabs.

  11. Methods to assess airborne concentrations of cotton dust.

    PubMed

    Corn, M

    1987-01-01

    Assessment of concentrations of airborne cotton dust in the factory is necessary to determine adherence to applicable Permissible Exposure Limits (PELs) on a day-to-day basis, as well as for investigatory studies of an epidemiological nature. The latter are required on an ongoing basis to determine the adequacy of PELs to prevent disease in the exposed population. A strategy of sampling includes considerations of the numbers of samples to be obtained for statistical validity and the locations of samples. Current practice is to obtain more "personal samples" of exposure wherever possible, but with regard to cotton dust, instrumentation is not available for such sampling. In the U.S., the vertical elutriator is the instrument of choice for determining the concentrations of cotton dust in air. Results are expressed as milligrams of airborne particulate (cotton dust) per cubic meter. PMID:3434562

  12. Exposure assessment to airborne endotoxin, dust, ammonia, hydrogen sulfide and carbon dioxide in open style swine houses.

    PubMed

    Chang, C W; Chung, H; Huang, C F; Su, H J

    2001-08-01

    Information is limited for the exposure levels of airborne hazardous substances in swine feed buildings that are not completely enclosed. Open-style breeding, growing and finishing swine houses in six farms in subtropical Taiwan were studied for the airborne concentrations of endotoxin, dust, ammonia, hydrogen sulfide and carbon dioxide. The air in the farrowing and nursery stalls as partially enclosed was also simultaneously evaluated. Three selected gases and airborne dusts were quantified respectively by using Drager diffusion tubes and a filter-weighing method. Endotoxin was analyzed by the Limulus amoebocyte lysate assay. Average concentration of airborne total endotoxin among piggeries was between 36.8 and 298 EU/m(3), while that for respirable endotoxin was 14.1-129 EU/m(3). Mean concentration of total dust was between 0.15 and 0.34 mg/m(3), with average level of respirable dust of 0.14 mg/m(3). The respective concentrations of NH3, CO2 and H2S were less than 5 ppm, 600-895 ppm and less than 0.2 ppm. Airborne concentrations of total dust and endotoxin in the nursery house were higher than in the other types of swine houses. The finishing house presented the highest exposure risk to NH3, CO2 and H2S. Employees working in the finishing stalls were also exposed to the highest airborne levels of respirable endotoxin and dust. On the other hand, the air of the breeding units was the least contaminated in terms of airborne endotoxin, dust, NH3, CO2 and H2S. The airborne concentrations of substances measured in the present study were all lower than most of published studies conducted in mainly enclosed swine buildings. Distinct characteristics, including maintaining swine houses in an open status and frequent spraying water inside the stalls, significantly reduce accumulation of gases and airborne particulates. PMID:11513795

  13. Airborne Dust Modified the North American Climate During the 1930's Dust Bowl

    NASA Astrophysics Data System (ADS)

    O'Brien, T. A.; Solmon, F.; Sloan, L. C.; Snyder, M. A.

    2007-05-01

    In the 1930's Dust Bowl, drought in Mid-Western North America, in conjunction with wide-scale planting of drought-vulnerable crops, resulted in massive dust storms. The presence of dust in the atmosphere may have directly altered the energy budget of North America by the scattering and absorption of radiation and thus may have acted as a feedback to the regional drought conditions. Through a climate modeling sensitivity study of North American climate investigating the impact of airborne dust during the 1930's (using a regional model, RegCM3), we find that areas with moderate to high dust-loading have reduced surface temperatures (~1K) and reduced evapotranspiration (~0.5 mm/day). We also find spatially-coherent, statistically significant changes in precipitation patterns over eastern North America during Spring, Summer, and Fall: areas gain and lose as much as 2 mm/day of precipitation. We are working on a more detailed analysis to determine the causal relationship(s) between airborne dust and precipitation patterns; we hypothesize that the spatially non-uniform change in the energy budget, caused by dust loading, modifies regional dynamics and indirectly modifies precipitation patterns.

  14. Domestic Mite Antigens in Floor and Airborne Dust at Workplaces in Comparison to Living Areas: A New Immunoassay to Assess Personal Airborne Allergen Exposure

    PubMed Central

    Sander, Ingrid; Zahradnik, Eva; Kraus, Gerhard; Mayer, Stefan; Neumann, Heinz-Dieter; Fleischer, Christina; Brüning, Thomas; Raulf-Heimsoth, Monika

    2012-01-01

    Objectives Allergens produced by domestic mites (DM) are among the most common allergic sensitizers and risk factors for asthma. To compare exposure levels between workplaces and living areas a new assay able to measure airborne DM antigen concentrations was developed. Methods At workplaces and in living areas, 213 floor dust samples and 92 personal inhalable dust samples were collected. For sensitive quantification of DM antigens, a new enzyme immunoassay (EIA) based on polyclonal antibodies to Dermatophagoides farinae extract was developed. Reactivity of five house dust mite and four storage mite species was tested. All dust samples were tested with the new EIA and with the Der f 1 and Der p 1-EIAs (Indoor Biotechnologies, UK) which detect major allergens from D. farinae and D. pteronyssinus by monoclonal antibodies. Samples below the detection limit in the DM-EIA were retested in an assay variant with a fluorogenic substrate (DM-FEIA). Results The newly developed DM-EIA detects antigens from all nine tested domestic mite species. It has a lower detection limit of 200 pg/ml of D.farinae protein, compared to 50 pg/ml for the DM-FEIA. DM antigens were detected by DM-EIA/FEIA in all floor dust and 80 (87%) of airborne samples. Der f 1 was found in 133 (62%) floor dust and in only 6 airborne samples, Der p 1 was found in 70 (33%) of floor samples and in one airborne sample. Der f 1 and DM concentrations were highly correlated. DM-antigens were significantly higher in inhalable airborne samples from textile recycling, bed feather filling, feed production, grain storage and cattle stables in comparison to living areas. Conclusions A new sensitive EIA directed at DM antigens was developed. DM antigen quantities were well correlated to Der f 1 values and were measurable in the majority (87%) of airborne dust samples. Some workplaces had significantly higher DM antigen concentrations than living areas. PMID:23285240

  15. Reducing airborne pathogens and dust in commercial hatching cabinets with an electrostatic space charge system.

    PubMed

    Mitchell, B W; Waltman, W D

    2003-01-01

    Commercial hatcheries typically infuse hydrogen peroxide or formaldehyde gas into hatching cabinets to reduce airborne pathogens that may lead to disease transmission during the hatch. A nonchemical option, an electrostatic space charge system (ESCS), was customized for full-sized commercial hatching cabinets and was tested extensively in broiler hatcheries. The ESCS cleans air by transferring a strong negative electrostatic charge to dust and microorganisms that are aerosolized during the hatch and collecting the charged particles on grounded plates or surfaces. In studies with three poultry companies, the ESCS resulted in significant (P < 0.0001) reductions of airborne dust of 77%-79%, in Enterobacteriaceae and fungus levels not significantly different (P > or = 0.05) from those with formaldehyde, and in 93%-96% lower Enterobacteriaceae than with no treatment or with hydrogen peroxide treatment (P < 0.01). The ESCS significantly (P < 0.05) reduced airborne Salmonella by 33%-83% compared with no treatment or hydrogen peroxide treatment. Results of this study suggest that the ESCS is a viable alternative to chemical treatment for reducing airborne pathogens in full-sized commercial hatchers, and it also provides dust control and containment, which should be helpful in reducing cross contamination and loading of ventilation ducts within different areas of the hatchery. PMID:12887184

  16. Detection of Coxiella burnetii DNA in Inhalable Airborne Dust Samples from Goat Farms after Mandatory Culling

    PubMed Central

    Hogerwerf, Lenny; Still, Kelly; Heederik, Dick; van Rotterdam, Bart; de Bruin, Arnout; Nielen, Mirjam; Wouters, Inge M.

    2012-01-01

    Coxiella burnetii is thought to infect humans primarily via airborne transmission. However, air measurements of C. burnetii are sparse. We detected C. burnetii DNA in inhalable and PM10 (particulate matter with an aerodynamic size of 10 μm or less) dust samples collected at three affected goat farms, demonstrating that low levels of C. burnetii DNA are present in inhalable size fractions. PMID:22582072

  17. Examination of water spray airborne coal dust capture with three wetting agents

    PubMed Central

    Organiscak, J.A.

    2015-01-01

    Water spray applications are one of the principal means of controlling airborne respirable dust in coal mines. Since many coals are hydrophobic and not easily wetted by water, wetting agents can be added to the spray water in an effort to improve coal wetting and assist with dust capture. In order to study wetting agent effects on coal dust capture, laboratory experiments were conducted with three wetting agents used by the coal industry on -325 mesh sized Pocahontas No. 3 coal dust. Significant differences in coal dust sink times were observed among the three wetting agents at water mixture concentrations of 0.05%, 0.1% and 0.2%. The best wetting agent as identified by the coal dust sink test was only tested at the lowest 0.05% water mixture concentration and was found to have a negligible effect on spray airborne dust capture. Water spray airborne dust capture results for all three wetting agents tested at a 0.2% water mixture concentration showed that all three wetting agents exhibit similar but small improvements in dust capture efficiency as compared with water. These results indicate that the coal dust sink test may not be a good predictor for the capture of airborne dust. Additional research is needed to examine if the coal dust sink test is a better predictor of wetting agent dust suppression effects during cutting, loading, conveying and dumping of coal products by comparison to airborne dust capture from sprays. PMID:26251565

  18. Latex allergens in tire dust and airborne particles.

    PubMed Central

    Miguel, A G; Cass, G R; Weiss, J; Glovsky, M M

    1996-01-01

    The prevalence and severity of latex allergy has increased dramatically in the last 15 years due to exposure to natural rubber products. Although historically this health risk has been elevated in hospital personnel and patients, a recent survey has indicated a significant potential risk for the general population. To obtain a wide-spread source for latex exposure, we have considered tire debris. We have searched for the presence of latex allergens in passenger car and truck tire tread, in debris deposited from the atmosphere near a freeway, and in airborne particulate matter samples representative of the entire year 1993 at two sites in the Los Angeles basin (California). After extraction of the samples with phosphate buffered saline, a modified-ELISA inhibition assay was used to measure relative allergen potency and Western blot analyses were used to identify latex allergens. The inhibition studies with the human IgE latex assay revealed inhibition by the tire tread source samples and ambient freeway dust, as well as by control latex sap and latex glove extracts. Levels of extractable latex allergen per unit of protein extracted were about two orders of magnitude lower for tire tread as compared to latex gloves. Western blot analyses using binding of human IgE from latex-sensitive patients showed a band at 34-36 kDa in all tire and ambient samples. Long Beach and Los Angeles, California, air samples showed four additional bands between 50 and 135 kDa. Alternative Western blot analyses using rabbit IgG raised against latex proteins showed a broad band at 30-50 kDa in all samples, with additional bands in the urban air samples similar to the IgE results. A latex cross-reactive material was identified in mountain cedar. In conclusion, the latex allergens or latex cross-reactive material present in sedimented and airborne particulate material, derived from tire debris, and generated by heavy urban vehicle traffic could be important factors in producing latex allergy

  19. Personal exposure to airborne dust and microorganisms in agricultural environments.

    PubMed

    Lee, Shu-An; Adhikari, Atin; Grinshpun, Sergey A; McKay, Roy; Shukla, Rakesh; Reponen, Tiina

    2006-03-01

    Airborne dust and microorganisms are associated with respiratory diseases and increased mortality and morbidity. Farmers are at high risk of exposure to both of these hazards. Very limited information, however, is available on the combined exposures to both hazards on different types of farms. Moreover, most of the previous studies have measured the mass concentration of particles ignoring the particle size. In this study, farmers' exposure to airborne dust and microorganisms was studied using our newly developed personal sampling system. Particle number concentration and size distribution were measured with an optical particle counter. Simultaneously, particles were collected on a filter and analyzed for microorganisms. The field measurements were conducted in animal confinements (swine, poultry, and dairy) and during grain harvesting (corn and soybean). The results show the following average concentrations on the workers' breathing zone: 1.7 x 10(6) to 2.9 x 10(7) particles/m(3) for total dust, 0.9 x 10(3) to 3.9 x 10(4) spores/m(3) for total fungal spores, 0.3 x 10(3) to 3.6 x 10(4)CFU/m(3) for culturable fungal spores, 0.3 x 10(4) to 3.3 x 10(8) CFU/m(3) for culturable bacteria, and limit of detection (LOD) to 2.8 x 10(3) CFU/m(3) for culturable actinomycetes in animal confinements. The respective concentrations were 4.4 x 10(6) to 5.8 x 10(7) particles/m(3), 3.4 x 10(4) to 6.1 x 10(6) spores/m(3), 8.2 x 10(4) to 7.4 x 10(6) CFU/m(3), 0.4 x 10(5) to 1.4 x 10(6) CFU/m(3), and LOD to 2.6 x 10(4) CFU/m(3) during grain harvesting. The highest contribution of large particles (3-10 microm) in total particles was found during grain harvesting, whereas the size distribution was dominated by smaller particles (< 3 microm) in animal confinements. High fraction (up to 37%) of particles between 2-10 microm was found to be fungal spores. The results indicate that an increase in the concentration of large dust particles (2-10 microm) during grain harvesting was partially

  20. 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

  1. Microbial immigration across the Mediterranean via airborne dust

    PubMed Central

    Rosselli, Riccardo; Fiamma, Maura; Deligios, Massimo; Pintus, Gabriella; Pellizzaro, Grazia; Canu, Annalisa; Duce, Pierpaolo; Squartini, Andrea; Muresu, Rosella; Cappuccinelli, Pietro

    2015-01-01

    Dust particles lifting and discharge from Africa to Europe is a recurring phenomenon linked to air circulation conditions. The possibility that microorganisms are conveyed across distances entails important consequences in terms of biosafety and pathogens spread. Using culture independent DNA-based analyses via next generation sequencing of the 16 S genes from the airborne metagenome, the atmospheric microbial community was characterized and the hypothesis was tested that shifts in species diversity could be recorded in relation to dust discharge. As sampling ground the island of Sardinia was chosen, being an ideal cornerstone within the Mediterranean and a crossroad of wind circulation amidst Europe and Africa. Samples were collected in two opposite coastal sites and in two different weather conditions comparing dust-conveying winds from Africa with a control situation with winds from Europe. A major conserved core microbiome was evidenced but increases in species richness and presence of specific taxa were nevertheless observed in relation to each wind regime. Taxa which can feature strains with clinical implications were also detected. The approach is reported as a recommended model monitoring procedure for early warning alerts in frameworks of biosafety against natural spread of clinical microbiota across countries as well as to prevent bacteriological warfare. PMID:26542754

  2. Microbial immigration across the Mediterranean via airborne dust.

    PubMed

    Rosselli, Riccardo; Fiamma, Maura; Deligios, Massimo; Pintus, Gabriella; Pellizzaro, Grazia; Canu, Annalisa; Duce, Pierpaolo; Squartini, Andrea; Muresu, Rosella; Cappuccinelli, Pietro

    2015-01-01

    Dust particles lifting and discharge from Africa to Europe is a recurring phenomenon linked to air circulation conditions. The possibility that microorganisms are conveyed across distances entails important consequences in terms of biosafety and pathogens spread. Using culture independent DNA-based analyses via next generation sequencing of the 16 S genes from the airborne metagenome, the atmospheric microbial community was characterized and the hypothesis was tested that shifts in species diversity could be recorded in relation to dust discharge. As sampling ground the island of Sardinia was chosen, being an ideal cornerstone within the Mediterranean and a crossroad of wind circulation amidst Europe and Africa. Samples were collected in two opposite coastal sites and in two different weather conditions comparing dust-conveying winds from Africa with a control situation with winds from Europe. A major conserved core microbiome was evidenced but increases in species richness and presence of specific taxa were nevertheless observed in relation to each wind regime. Taxa which can feature strains with clinical implications were also detected. The approach is reported as a recommended model monitoring procedure for early warning alerts in frameworks of biosafety against natural spread of clinical microbiota across countries as well as to prevent bacteriological warfare. PMID:26542754

  3. Health effects of particulate air pollution and airborne desert dust

    NASA Astrophysics Data System (ADS)

    Lelieveld, J.; Pozzer, A.; Giannadaki, D.; Fnais, M.

    2013-12-01

    Air pollution by fine particulate matter (PM2.5) has increased strongly with industrialization and urbanization. In the past decades this increase has taken place at a particularly high pace in South and East Asia. We estimate the premature mortality and the years of human life lost (YLL) caused by anthropogenic PM2.5 and airborne desert dust (DU2.5) on regional and national scales (Giannadaki et al., 2013; Lelieveld et al., 2013). This is based on high-resolution global model calculations that resolve urban and industrial regions in relatively great detail. We apply an epidemiological health impact function and find that especially in large countries with extensive suburban and rural populations, air pollution-induced mortality rates have been underestimated given that previous studies largely focused on the urban environment. We calculate a global premature mortality by anthropogenic aerosols of 2.2 million/year (YLL ≈ 16 million/year) due to lung cancer and cardiopulmonary disease. High mortality rates by PM2.5 are found in China, India, Bangladesh, Pakistan and Indonesia. Desert dust DU2.5 aerosols add about 0.4 million/year (YLL ≈ 3.6 million/year). Particularly significant mortality rates by DU2.5 occur in Pakistan, China and India. The estimated global mean per capita mortality caused by airborne particulates is about 0.1%/year (about two thirds of that caused by tobacco smoking). We show that the highest premature mortality rates are found in the Southeast Asia and Western Pacific regions (about 25% and 46% of the global rate, respectively) where more than a dozen of the most highly polluted megacities are located. References: Giannadaki, D., A. Pozzer, and J. Lelieveld, Modeled global effects of airborne desert dust on air quality and premature mortality, Atmos. Chem. Phys. Discuss. (submitted), 2013. Lelieveld, J., C. Barlas, D. Giannadaki, and A. Pozzer, Model calculated global, regional and megacity premature mortality due to air pollution by ozone

  4. Exposure to airborne microorganisms, dust and endotoxin during processing of peppermint and chamomile herbs on farms.

    PubMed

    Skórska, Czesława; Sitkowska, Jolanta; Krysińska-Traczyk, Ewa; Cholewa, Grazyna; Dutkiewicz, Jacek

    2005-01-01

    The aim of this study was to determine the levels of microorganisms, dust and endotoxin in the air during processing of peppermint (Mentha piperita) and chamomile (Matricaria recutita) by herb farmers, and to examine the species composition of airborne microflora. Air samples were collected on glass fibre filters by use of personal samplers on 13 farms owned by herb cultivating farmers, located in Lublin province (eastern Poland). The concentrations of total viable microorganisms (bacteria + fungi) in the farm air during processing of peppermint herb were large, within a range from 895.1-6,015.8 x 10(3) cfu/m(3) (median 1,055.3 x 10(3) cfu/m(3)). During processing of chamomile herb they were much lower and varied within a range from 0.88-295.6 x 10(3) cfu/m(3) (median 27.3 x 10(3) cfu/m(3)). Gram-negative bacteria distinctly prevailed during processing of peppermint leaves, forming 46.4-88.5 % of the total airborne microflora. During processing of chamomile herb, Gram-negative bacteria were dominant at 3 out of 6 sampling sites forming 54.7-75.3 % of total microflora, whereas at the remaining 3 sites the most common were fungi forming 46.2-99.9 % of the total count. The species Pantoea agglomerans (synonyms: Erwinia herbicola, Enterobacter agglomerans ), having strong allergenic and endotoxic properties, distinctly prevailed among Gram-negative isolates. Among fungi, the most common species was Alternaria alternata. The concentrations of airborne dust and endotoxin determined on the examined herb farms were large. The concentrations of airborne dust during peppermint and chamomile processing ranged from 86.7-958.9 mg/m(3), and from 1.1-499.2 mg/m(3), respectively (medians 552.3 mg/m(3) and 12.3 mg/m(3)). The concentrations of airborne endotoxin determined during peppermint and chamomile processing were within a wide range 1.53-208.33 microg/m(3) and 0.005-2604.19 microg/m(3) respectively (medians 57.3 microg/m(3) and 0.96 microg/m(3)). In conclusion, farmers

  5. Levels of gram-negative bacteria, Aspergillus fumigatus, dust, and endotoxin at compost plants.

    PubMed Central

    Clark, C S; Rylander, R; Larsson, L

    1983-01-01

    Airborne gram-negative bacteria, endotoxins, dust, and Aspergillus fumigatus were measured in four compost plants in Sweden. At sites where material was processed, the number of airborne A. fumigatus exceeded 10(6)/m3, whereas the number of gram-negative bacteria was usually lower. Dust levels were moderate, and endotoxin levels were well below 0.5 micrograms/m3. Medical studies to evaluate the effects of this type of microbial exposure are recommended. PMID:6347061

  6. Sensory and other neurogenic effects of exposures to airborne office dust

    NASA Astrophysics Data System (ADS)

    Mølhave, L.; Kjærgaard, S. K.; Attermann, J.

    This Danish Office Dust Experiment investigated the response of 24 healthy non-sensitive adult subjects to exposure to normal office dust in the air (7 μg m -3 clean air, 136 and 390 μg m -3 TSP). The dust had no major identifiable specific reactive components. The exposure duration was 5 1/4 h and was arranged in a climate chamber in controlled atmospheric conditions. Measurements were made acutely at exposure onset, subacutely at exposure end and next day (late). As secondary aims the time course and threshold of any observed effect of the exposures, and the characteristics of any hyperresponding subgroup were investigated. In a questionnaire with 36 questions the dust exposures caused increased acute, subacute and late perceptions of reduced air quality, acute and subacute increased odor intensity, acute eye irritation, acute and late heavy head, subacute feeling of perspiration, and subacute general irritation. Cough increased subacutely during exposures. In addition, a performance test showed effects of dust exposures which also affected "Mood Scale" ratings. No effect was seen on an addition test for distraction, and objective measurements of skin humidity. The overall conclusion of the study is that healthy subjects without hypersensitivity reactions seem to respond to airborne house dust. The responses are both subjective sensory reactions and other neurogenic effects even at exposure levels within the range found in normal buildings. Some of the effects appeared acutely and decreased through adaptation while others increased during prolonged exposure and remained for more than 17 h after the exposure ended. The findings may indicate for this type of dust a threshold level for the dose-response relationships below 140 μg m -3.

  7. Analysis of Potentially Toxic Metals in Airborne Cement Dust Around Sagamu, Southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Gbadebo, A. M.; Bankole, O. D.

    This study analyzed the concentration levels of potentially toxic and harmful elements contained in the airborne cement dust generated in the vicinity and farther away 500 m in the conventional four cardinal directions from the West African Portland Cement Company (WAPCO) factory mill, Sagamu. The results indicated that the concentration range of these toxic elements fall between 40.0 and 280,000 μg g-1 in the cement dust samples. Also, the concentration range of these toxic elements in 1 L of air samples varies between 0.01 μg g-1 and 29.92 μg L-1. The results generally show elevated concentrations of all the elements when compared with USA threshold limit of particulate mental concentration (e.g., Pb (1.5 g m-3); Cd (0.004-0.026 g m-3) in the air. These elements in the airborne cement dusts may pose a great threat to the health of plants, animals and residents in and around the factory and also to workers and visitors to the factory.

  8. 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

  9. Influence of various dust sampling and extraction methods on the measurement of airborne endotoxin.

    PubMed

    Douwes, J; Versloot, P; Hollander, A; Heederik, D; Doekes, G

    1995-05-01

    The influence of various filter types and extraction conditions on the quantitation of airborne endotoxin with the Limulus amebocyte lysate test was studied by using airborne dusts sampled in a potato processing plant. Samples were collected with an apparatus designed to provide parallel samples. Data from the parallel-sampling experiment were statistically evaluated by using analysis of variance. In addition, the influence of storage conditions on the detectable endotoxin concentration was investigated by using commercially available lipopolysaccharides (LPS) and endotoxin-containing house dust extracts. The endotoxin extraction efficiency of 0.05% Tween 20 in pyrogen-free water was seven times higher than that of pyrogen-free water only. Two-times-greater amounts of endotoxin were extracted from glass fiber, Teflon, and polycarbonate filters than from cellulose ester filters. The temperature and shaking intensity during extraction were not related to the extraction efficiency. Repeated freeze (-20 degrees C)-and-thaw cycles with commercial LPS reconstituted in pyrogen-free water had a dramatic effect on the detectable endotoxin level. A 25% loss in endotoxin activity per freeze-thaw cycle was observed. Storage of LPS samples for a period of 1 year at 7 degrees C had no effect on the endotoxin level. House dust extracts showed a decrease of about 20% in the endotoxin level after they had been frozen and thawed for a second time. The use of different container materials (borosilicate glass, "soft" glass, and polypropylene) did not result in different endotoxin levels. This study indicates that the assessment of endotoxin exposure may differ considerably between groups when different sampling, extraction, and storage procedures are employed. PMID:7646014

  10. Influence of various dust sampling and extraction methods on the measurement of airborne endotoxin.

    PubMed Central

    Douwes, J; Versloot, P; Hollander, A; Heederik, D; Doekes, G

    1995-01-01

    The influence of various filter types and extraction conditions on the quantitation of airborne endotoxin with the Limulus amebocyte lysate test was studied by using airborne dusts sampled in a potato processing plant. Samples were collected with an apparatus designed to provide parallel samples. Data from the parallel-sampling experiment were statistically evaluated by using analysis of variance. In addition, the influence of storage conditions on the detectable endotoxin concentration was investigated by using commercially available lipopolysaccharides (LPS) and endotoxin-containing house dust extracts. The endotoxin extraction efficiency of 0.05% Tween 20 in pyrogen-free water was seven times higher than that of pyrogen-free water only. Two-times-greater amounts of endotoxin were extracted from glass fiber, Teflon, and polycarbonate filters than from cellulose ester filters. The temperature and shaking intensity during extraction were not related to the extraction efficiency. Repeated freeze (-20 degrees C)-and-thaw cycles with commercial LPS reconstituted in pyrogen-free water had a dramatic effect on the detectable endotoxin level. A 25% loss in endotoxin activity per freeze-thaw cycle was observed. Storage of LPS samples for a period of 1 year at 7 degrees C had no effect on the endotoxin level. House dust extracts showed a decrease of about 20% in the endotoxin level after they had been frozen and thawed for a second time. The use of different container materials (borosilicate glass, "soft" glass, and polypropylene) did not result in different endotoxin levels. This study indicates that the assessment of endotoxin exposure may differ considerably between groups when different sampling, extraction, and storage procedures are employed. PMID:7646014

  11. Exposure to airborne microorganisms, dust and endotoxin during processing of valerian roots on farms.

    PubMed

    Skórska, Czesława; Sitkowska, Jolanta; Krysińska-Traczyk, Ewa; Cholewa, Grazyna; Dutkiewicz, Jacek

    2005-01-01

    The aim of this study was to determine the levels of microorganisms, dust and endotoxin in the air during various stages of valerian (Valeriana officinalis) roots processing by herb farmers and to examine the species composition of airborne microflora. Air samples were collected on glass fibre filters by use of personal samplers on 15 farms owned by valerian cultivating farmers, located in Lublin province (eastern Poland). The concentrations of total viable microorganisms (bacteria + fungi) in the air showed a marked variability and were within a range of 0.95-7,966.6 x 10(3) cfu/m (3). Though median was relatively low (10.75 x 10(3) cfu/m (3)), on 4 farms the concentrations exceeded the level of 10(5) cfu/m (3) and on 1 farm the level of 10(6) cfu/m (3). During the processing of valerian roots, distinct changes could be observed in the composition of airborne microflora. In the first stages of processing, the freshly dug and washed roots until shaking in the drying room, the most numerous were Gram-negative bacteria of the family Pseudomonadaceae (mostly Stenotrophomonas maltophilia, Pseudomonas chlororaphis and Pseudomonas fluorescens). After drying, the dominant organisms were thermo-resistant endospore-forming bacilli (Bacillus spp.) and fungi, among which prevailed Aspergillus fumigatus. Altogether, 29 species or genera of bacteria and 19 species or genera of fungi were identified in the farm air during valerian processing, of these, 10 and 12 species or genera respectively were reported as having allergenic and/or immunotoxic properties. The concentrations of airborne dust and endotoxin on the examined farms were very large and ranged from 10.0-776.7 mg/m (3), and from 0.15-24,448.2 microg/m (3), respectively (medians 198.3 mg/m (3) and 40.48 microg/m (3)). In conclusion, farmers cultivating valerian could be exposed during processing of valerian roots to large concentrations of airborne microorganisms, dust and endotoxin posing a risk of work

  12. Airborne Fungal and Bacterial Components in PM1 Dust from Biofuel Plants

    PubMed Central

    Madsen, Anne Mette; Schlünssen, Vivi; Olsen, Tina; Sigsgaard, Torben; Avci, Hediye

    2009-01-01

    Fungi grown in pure cultures produce DNA- or RNA-containing particles smaller than spore size (<1.5 μm). High exposures to fungi and bacteria are observed at biofuel plants. Airborne cultivable bacteria are often described to be present in clusters or associated with larger particles with an aerodynamic diameter (dae) of 2–8 μm. In this study, we investigate whether airborne fungal components smaller than spore size are present in bioaerosols in working areas at biofuel plants. Furthermore, we measure the exposure to bacteria and fungal components in airborne particulate matter (PM) with a D50 of 1 μm (called PM1 dust). PM1 was sampled using Triplex cyclones at a working area at 14 Danish biofuel plants. Millipore cassettes were used to sample ‘total dust’. The PM1 particles (29 samples) were analysed for content of 11 different components and the total dust was analysed for cultivable fungi, N-acetyl-β-D-glucosaminidase (NAGase), and (1 → 3)-β-D-glucans. In the 29 PM1 samples, cultivable fungi were found in six samples and with a median concentration below detection level. Using microscopy, fungal spores were identified in 22 samples. The components NAGase and (1 → 3)-β-D-glucans, which are mainly associated with fungi, were present in all PM1 samples. Thermophilic actinomycetes were present in 23 of the 29 PM1 samples [average = 739 colony-forming units (CFU) m−3]. Cultivable and ‘total bacteria’ were found in average concentrations of, respectively, 249 CFU m−3 and 1.8 × 105 m−3. DNA- and RNA-containing particles of different lengths were counted by microscopy and revealed a high concentration of particles with a length of 0.5–1.5 μm and only few particles >1.5 μm. The number of cultivable fungi and β-glucan in the total dust correlated significantly with the number of DNA/RNA-containing particles with lengths of between 1.0 and 1.5 μm, with DNA/RNA-containing particles >1.5 μm, and with other fungal components in PM1

  13. On the visibility of airborne volcanic ash and mineral dust

    NASA Astrophysics Data System (ADS)

    Weinzierl, B.; Sauer, D. N.; Minikin, A.; Reitebuch, O.; Dahlkötter, F.; Mayer, B. C.; Emde, C.; Tegen, I.; Gasteiger, J.; Petzold, A.; Veira, A.; Kueppers, U.; Schumann, U.

    2012-12-01

    After the eruption of the Eyjafjalla volcano (Iceland) in April 2010 which caused the most extensive restrictions of the airspace over Europe since the end of World War II, the aviation safety concept of avoiding "visible ash", i.e. volcanic ash that can be seen by the human eye, was recommended. However so far, no clear definition of "visible ash" and no relation between the visibility of an aerosol layer and related aerosol mass concentrations are available. The goal of our study is to assess whether it is possible from the pilot's perspective in flight to detect the presence of volcanic ash and to distinguish between volcanic ash and other aerosol layers just by sight. In our presentation, we focus the comparison with other aerosols on aerosol types impacting aviation: Besides volcanic ash, dust storms are known to be avoided by aircraft. We use in-situ and lidar data as well photographs taken onboard the DLR research aircraft Falcon during the Saharan Mineral Dust Experiments (SAMUM) in 2006 and 2008 and during the Eyjafjalla volcanic eruption in April/May 2010. We complement this analysis with numerical modelling, using idealized radiative transfer simulations with the 3D Monte Carlo radiative transfer code MYSTIC for a variety of selected viewing geometries. Both aerosol types, Saharan mineral dust and volcanic ash, show an enhanced coarse mode (> 1 μm) aerosol concentration, but volcanic ash aerosol additionally contains a significant number of Aitken mode particles (< 150 nm). Volcanic ash is slightly more absorbing than mineral dust, and the spectral behaviour of the refractive index is slightly different. According to our simulations, these differences are not detectable just by human eye. Furthermore, our data show, that it is difficult to define a lower threshold for the visibility of an aerosol layer because the visual detectability depends on many parameters, including the thickness of the aerosol layer, the brightness and color contrast between the

  14. Airborne chemistry single cell level

    NASA Astrophysics Data System (ADS)

    Nilsson, Staffan; Viberg, Peter; Spegel, Peter; Santesson, Sabina; Cedergren, Eila; Degerman, Eva; Johansson, Tomas; Nilsson, Johan

    2002-11-01

    A miniaturized analysis system for the studying of living cells and biochemical reactions in microdrops was developed. Cell studies were performed using single adipocytes in 250-nL drops. Continuous flow-through droplet dispensers, developed in-house, were used for additions to the levitated droplet. Addition of b-adrenergic agonists stimulates the lipolysis in the adipocytes, leading to free fatty acid release and a consequent pH decrease of the surrounding buffer, a change that can be easily followed using a pH-dependent fluorophore continuously monitored by fluorescence imaging detection. An analytical method using capillary electrophoresis and nanospray mass spectrometry for measurement of the cAMP level in activated single adipocytes are now being developed for future use in combination with the levitation technique. The levitation approach was also employed for the screening of nucleation conditions for macromolecules. Here, the acoustic levitator offers a simplified way to determine the main features of the phase diagram (i.e., precipitation diagram). Using the droplet dispensers, different types and amounts of precipitation agents are injected into the levitated drop, allowing a systematic search for nucleation conditions that is not possible using standard crystallization methods. Once the precipitation diagram has been obtained, optimization using standard methods is employed to grow the crystals.

  15. Comparison of Air Impaction and Electrostatic Dust Collector Sampling Methods to Assess Airborne Fungal Contamination in Public Buildings.

    PubMed

    Normand, Anne-Cécile; Ranque, Stéphane; Cassagne, Carole; Gaudart, Jean; Sallah, Kankoé; Charpin, Denis-André; Piarroux, Renaud

    2016-03-01

    Many ailments can be linked to exposure to indoor airborne fungus. However, obtaining a precise measurement of airborne fungal levels is complicated partly due to indoor air fluctuations and non-standardized techniques. Electrostatic dust collector (EDC) sampling devices have been used to measure a wide range of airborne analytes, including endotoxins, allergens, β-glucans, and microbial DNA in various indoor environments. In contrast, viable mold contamination has only been assessed in highly contaminated environments such as farms and archive buildings. This study aimed to assess the use of EDCs, compared with repeated air-impactor measurements, to assess airborne viable fungal flora in moderately contaminated indoor environments. Indoor airborne fungal flora was cultured from EDCs and daily air-impaction samples collected in an office building and a daycare center. The quantitative fungal measurements obtained using a single EDC significantly correlated with the cumulative measurement of nine daily air impactions. Both methods enabled the assessment of fungal exposure, although a few differences were observed between the detected fungal species and the relative quantity of each species. EDCs were also used over a 32-month period to monitor indoor airborne fungal flora in a hospital office building, which enabled us to assess the impact of outdoor events (e.g. ground excavations) on the fungal flora levels on the indoor environment. In conclusion, EDC-based measurements provided a relatively accurate profile of the viable airborne flora present during a sampling period. In particular, EDCs provided a more representative assessment of fungal levels compared with single air-impactor sampling. The EDC technique is also simpler than performing repetitive air-impaction measures over the course of several consecutive days. EDC is a versatile tool for collecting airborne samples and was efficient for measuring mold levels in indoor environments. PMID:26491105

  16. Contribution of airborne dust particles to HONO sources

    NASA Astrophysics Data System (ADS)

    Saliba, N. A.; Moussa, S. G.; El Tayyar, G.

    2014-02-01

    HONO is a major precursor for OH radicals in early mornings. Its formation has been mainly attributed to the heterogeneous hydrolysis of NO2 on surfaces such as soot, glass, mineral oxides and aerosol surfaces. In particular, dust events which are loaded with mineral oxide aerosols have been associated with higher HONO concentrations in the gas phase. In order to understand the mechanism of reactions related to this process, samples during dusty and non-dusty days were collected between October 2009 and April 2011. Based on HYSPLIT backward trajectories, data were divided between wind trajectories originating from Arabian or African deserts. In this study an increase of HONO levels was observed during dusty days. The increase in the acidic gas concentrations was accompanied by an increase in the PM nitrate and sulfate ion concentrations. During high relative humidity (African dusty days), it is proposed that the mechanism of NO2 hydrolysis predominates whereas during Arabian dusty days, where the air is relatively dry, a synergistic mechanism of adsorption and reaction between NO2 and SO2 on dust particles to produce HONO and sulfate in the particle phase is suggested. This study implies that the NOx reactivity on mineral oxide surfaces leads to a higher mixing level of OH. An increase in the sulfate forming capacity could account for the underestimation of sulfates in aerosols when the reactive uptake of SO2 alone is considered.

  17. Airborne desert dust and aeromicrobiology over the Turkish Mediterranean coastline

    USGS Publications Warehouse

    Griffin, Dale W.; Kubilay, Nilgün; Kocak, Mustafa; Gray, Mike A.; Borden, Timothy C.; Shinn, Eugene A.

    2007-01-01

    Between 18 March and 27 October 2002, 220 air samples were collected on 209 of 224 calendar days, on top of a coastal atmospheric research tower in Erdemli, Turkey. The volume of air filtered for each sample was 340 liters. Two hundred fifty-seven bacterial and 2598 fungal colony forming units (CFU) were enumerated from the samples using a low-nutrient agar. Ground-based dust measurements demonstrated that the region is routinely impacted by dust generated regionally and from North Africa and that the highest combined percent recovery of total CFU and African dust deposition occurred in the month of April (93.4% of CFU recovery and 91.1% of dust deposition occurred during African dust days versus no African dust present, for that month). A statistically significant correlation was observed (peak regional African dust months of March, April and May; rs=0.576, P=0.000) between an increase in the prevalence of microorganisms recovered from atmospheric samples on dust days (regional and African as determined by ground-based dust measurements), versus that observed on non-dust days. Given the prevalence of atmospherically suspended desert dust and microorganisms observed in this study, and that culture-based studies typically only recover a small fraction (

  18. Long-Term Variability of Airborne Asian Dust Observed from TOMS

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Hsu, N. C.; Seftor, C. J.; Holben, B. N.; Holben, B. N.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Recent studies suggest that airborne Asian dust may not only play an important role in the regional radiation budget, but also influence the air quality over North America through long-range transport. In this paper, we use satellite data to investigate the long-term variability of airborne Asian dust as well as the daily variation of the dust aerosol distribution. By combining the Total Ozone Mapping Spectrometer (TOMS) aerosol index with National Centers for Environmental Prediction (NCEP) wind data, our analysis shows a strong correlation between the generation of dust storms in the region and the passage of springtime weather fronts. This is consistent with earlier studies performed by other researchers. According to both the Nimbus-7 and Earth-Probe TOMS data the Takla Makan desert, the Gobi desert, and the and region of Inner Mongolia are major sources of the eastward-flowing airborne Asian dust. Heavily populated areas in eastern China (e.g., Beijing) are often on the primary path of the dust storms originating in these desert regions. The increasing desertification north of the Beijing region has served to exacerbate problems stemming from these storms. The time series derived from 20 years of TOMS aerosol index data shows the first significant satellite evidence of the atmospheric effect of increasing desertification, indicating that the amount of dust blown eastward has increased strongly during the past few years including the year 2000.

  19. Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, volume 73

    NASA Technical Reports Server (NTRS)

    Haas, Michael R. (Editor); Davidson, Jacqueline A. (Editor); Erickson, Edwin F. (Editor)

    1995-01-01

    This symposium was organized to review the science related to NASA's Airborne Astronomy Program on the occasion of the twentieth anniversary of the Kuiper Airborne Observatory (KAO). The theme selected, 'The Galactic Ecosystem: From Gas to Stars to Dust,' was considered to capture the underlying commonality of much of the research discussed. The 8 sessions were as follows: The Interstellar Medium; The Life Cycle of the ISM in Other Galaxies; Star and Planetary System Formation; Our Planetary System: The Solar System; The Enrichment of the Interstellar Medium; The Galactic Center: A Unique Region of the Galactic Ecosystem; Instrumentation for Airborne Astronomy; KAO History and Education; and Missions and the Future of Infrared Astronomy.

  20. Ozone on Mars - The effects of clouds and airborne dust

    NASA Astrophysics Data System (ADS)

    Lindner, B. L.

    1988-02-01

    Photochemistry in the winter polar atmosphere of Mars is examined for several latitudes, cloud types and dust abundances. Variations in cloud opacities and cloud types change O3 abundances only a few percent. However, typical dust abundances induce 10 - 50% increases in O3 abundances, primarily because photodissociation rates are drastically reduced by dust absorption. Furthermore, annual, latitudinal and seasonal cycles in dust opacity cause variations of 50% or greater in the corresponding cycles in O3 abundances. The reflectance spectroscopy technique that has been used to measure the O3 abundance may have difficulty detecting these variations.

  1. Changes in the Airborne Bacterial Community in Outdoor Environments following Asian Dust Events

    PubMed Central

    Yamaguchi, Nobuyasu; Park, Jonguk; Kodama, Makiko; Ichijo, Tomoaki; Baba, Takashi; Nasu, Masao

    2014-01-01

    Bacterial abundance and community compositions have been examined in aeolian dust in order to clarify their possible impacts on public health and ecosystems. The influence of transcontinentally transported bacterial cells on microbial communities in the outdoor environments of downwind areas should be determined because the rapid influx of a large amount of bacterial cells can disturb indigenous microbial ecosystems. In the present study, we analyzed bacteria in air samples (approximately 100 m3 d−1) that were collected on both Asian dust days and non-Asian dust days over 2 years (between November 2010 and July 2012). Changes in bacterial abundance and community composition were investigated based on their 16S rRNA gene amount and sequence diversity. Seasonal monitoring revealed that airborne bacterial abundance was more than 10-fold higher on severe dust days, while moderate dust events did not affect airborne bacterial abundance. A comparison of bacterial community compositions revealed that bacteria in Asian dust did not immediately disturb the airborne microbial community in areas 3,000–5,000 km downwind of dust source regions, even when a large amount of bacterial cells were transported by the atmospheric event. However, microbes in aeolian dust may have a greater impact on indigenous microbial communities in downwind areas near the dust source. Continuous temporal and spatial analyses from dust source regions to downwind regions (e.g., from the Gobi desert to China, Korea, Japan, and North America) will assist in estimating the impact of atmospherically transported bacteria on indigenous microbial ecosystems in downwind areas. PMID:24553107

  2. Assessment of chemical and mineralogical characteristics of airborne dust in the Sistan region, Iran.

    PubMed

    Rashki, A; Eriksson, P G; Rautenbach, C J de W; Kaskaoutis, D G; Grote, W; Dykstra, J

    2013-01-01

    Windblown transport and deposition of dust is widely recognized as an important physical and chemical concern to climate, human health and ecosystems. Sistan is a region located in southeast Iran with extensive wind erosion, severe desertification and intense dust storms, which cause adverse effects in regional air quality and human health. To mitigate the impact of these phenomena, it is vital to ascertain the physical and chemical characteristics of airborne and soil dust. This paper examines for the first time, the mineralogical and chemical properties of dust over Sistan by collecting aerosol samples at two stations established close to a dry-bed lake dust source region, from August 2009 to August 2010. Furthermore, soil samples were collected from topsoil (0-5 cm depth) at several locations in the dry-bed Hamoun lakes and downwind areas. These data were analyzed to investigate the chemical and mineralogical characteristics of dust, relevance of inferred sources and contributions to air pollution. X-ray Diffraction (XRD) analysis of airborne and soil dust samples shows that the dust mineralogy is dominated mainly by quartz (30-40%), calcite (18-23%), muscovite (10-17%), plagioclase (9-12%), chlorite (~6%) and enstatite (~3%), with minor components of dolomite, microcline, halite and gypsum. X-ray Fluorescence (XRF) analyses of all the samples indicate that the most important oxide compositions of the airborne and soil dust are SiO(2), CaO, Al(2)O(3), Na(2)O, MgO and Fe(2)O(3), exhibiting similar percentages for both stations and soil samples. Estimates of Enrichment Factors (EFs) for all studied elements show that all of them have very low EF values, suggesting natural origin from local materials. The results suggest that a common dust source region can be inferred, which is the eroded sedimentary environment in the extensive Hamoun dry lakes lying to the north of Sistan. PMID:22835867

  3. Using proximate analysis to characterize airborne dust generation from bituminous coals

    SciTech Connect

    Page, S.J.; Organiscak, J.A.

    2005-11-01

    Prolonged exposure to airborne respirable coal dust is responsible for coal workers pneumoconiosis (CWP), commonly called black lung. Health research studies have identified that the prevalence and severity of CWP are directly related to both the amount of dust exposure and the coal rank. The amount of airborne respirable dust (ARD) smaller than 10 micrometers generated from breakage of different coals varies widely. To investigate the cause, researchers for the National Institute for Occupational Safety and Health (NIOSH) have conducted experiments to identify the causes of airborne respirable dust liberation. Laboratory crushing experiments were conducted on a range of low to high volatile bituminous coals from eight mines. The results indicate that the proximate analysis of a coal sample can provide a very good indicator of the potential for a dust problem. For application to the coal mining, processing, and utilization industries, data from 977 US coal seams compiled by the Department of Energy (DoE) has been used to calculate this dust generation potential from an equation based on the NIOSH measured data. A simple procedure for this calculation is provided. 1 fig.

  4. Airborne Dust, "The Good Guy or the Bad Guy": How Much do We Know?

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee

    2010-01-01

    Processes in generating, transporting, and dissipating the airborne dust particles are global phenomena -African dust regularly reaching the Alps; Asian dust seasonally crossing the Pacific into North America, and ultimately the Atlantic into Europe. One of the vital biogeochemical roles dust storms play in Earth's ecosystem is routinely mobilizing mineral dust, as a source of iron, from deserts into oceans for fertilizing the growth of phytoplankton -the basis of the oceanic food chain. Similarly, these dust-laden airs also supply crucial nutrients for the soil of tropical rain forests, the so-called womb of life that hosts 50-90% of the species on Earth. With massive amounts of dust lifted from desert regions and injected into the atmosphere, however, these dust storms often affect daily activities in dramatic ways: pushing grit through windows and doors, forcing people to stay indoors, causing breathing problems, reducing visibility and delaying flights, and by and large creating chaos. Thus, both increasing and decreasing concentrations of doses result in harmful biological effects; so do the airborne dust particles to our Living Earth. Since 1997 NASA has been successfully launching a series of satellites - the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite, in major international research projects such

  5. Investigating the causes of airborne dust in Western United States

    NASA Astrophysics Data System (ADS)

    Kavouras, I. G.; Etyemezian, V.; Xu, J.; Dubois, D.; Pitchford, M.; Green, M.

    2005-12-01

    Dust is a principal component of haze at many of the Western Class I Areas as defined by the Clean Air Act (CAA) adopted by the US congress on 1977. The magnitude of the impact of dust on haze varies by region as well as by season due to source variations in spatial scale, time, location, and causes of emission. Windblown dust emissions occur on both local and regional scales and the magnitude of dust emissions depends on man-made activities, soil properties and meteorology. On a transcontinental scale, enormous, regional dust storms can be transported across oceans and continents and impact the entire western United States. The target of this study was to specifically identify the causes of dust measured in the Class I areas of the western states by developing a methodology for assigning worst-case visibility days when dust was the major component at IMPROVE monitors within the WRAP domain to a set of source-categories over the period 2001 - 2003. The methodology included the development and implementation of the following tools: (i) concentration diagnostic ratios; (ii) multivariate linear regression analysis; (iii) air masses backward trajectories analysis; (iv) land use characteristics and; (v) soil properties. Each day was attributed to: (i) Transcontinental transport of large scale events from Asia; (ii) Small scale local windblown dust events; (iii) A combination of local and regional windblown dust events; (iv) Upwind transport and (v) Other unknown sources. The study included 71 sites from the IMPROVE network located in the Western Regional Air Partnership (WRAP) domain. Meteorological data including wind speed and direction and, precipitation (if available) were retrieved from meteorological stations in the vicinity of the IMPROVE monitors and used to estimate the contribution of "locally" generated windblown dust to visibility impairment. The spatial and temporal variation of the number of days attributed to the aforementioned source-categories was

  6. The role of airborne mineral dusts in human disease

    NASA Astrophysics Data System (ADS)

    Morman, Suzette A.; Plumlee, Geoffrey S.

    2013-06-01

    Exposure to fine particulate matter (PM) is generally acknowledged to increase risk for human morbidity and mortality. However, particulate matter (PM) research has generally examined anthropogenic (industry and combustion by-products) sources with few studies considering contributions from geogenic PM (produced from the Earth by natural processes, e.g., volcanic ash, windborne ash from wildfires, and mineral dusts) or geoanthropogenic PM (produced from natural sources by processes that are modified or enhanced by human activities, e.g., dusts from lakebeds dried by human removal of water, dusts produced from areas that have undergone desertification as a result of human practices). Globally, public health concerns are mounting, related to potential increases in dust emission from climate related changes such as desertification and the associated long range as well as local health effects. Recent epidemiological studies have identified associations between far-traveled dusts from primary sources and increased morbidity and mortality in Europe and Asia. This paper provides an outline of public health research and history as it relates to naturally occurring inorganic mineral dusts. We summarize results of current public health research and describe some of the many challenges related to understanding health effects from exposures to dust aerosols.

  7. Airborne Dust Cloud Measurements at the INL National Security Test Range

    SciTech Connect

    Michael L. Abbott; Norm Stanley; Larry Radke; Charles Smeltzer

    2007-09-01

    On July 11, 2007, a surface, high-explosive test (<20,000 lb TNT-equivalent) was carried out at the National Security Test Range (NSTR) on the Idaho National Laboratory (INL) Site. Aircraft-mounted rapid response (1-sec) particulate monitors were used to measure airborne PM-10 concentrations directly in the dust cloud and to develop a PM-10 emission factor that could be used for subsequent tests at the NSTR. The blast produced a mushroom-like dust cloud that rose approximately 2,500–3,000 ft above ground level, which quickly dissipated (within 5 miles of the source). In general, the cloud was smaller and less persistence than expected, or that might occur in other areas, likely due to the coarse sand and subsurface conditions that characterize the immediate NSTR area. Maximum short time-averaged (1-sec) PM-10 concentrations at the center of the cloud immediately after the event reached 421 µg m-3 but were rapidly reduced (by atmospheric dispersion and fallout) to near background levels (~10 µg m-3) after about 15 minutes. This occurred well within the INL Site boundary, about 8 km (5 miles) from the NSTR source. These findings demonstrate that maximum concentrations in ambient air beyond the INL Site boundary (closest is 11.2 km from NSTR) from these types of tests would be well within the 150 µg m-3 24-hour National Ambient Air Quality Standards for PM-10. Aircraft measurements and geostatistical techniques were used to successfully quantify the initial volume (1.64E+9 m3 or 1.64 km3) and mass (250 kg) of the PM-10 dust cloud, and a PM-10 emission factor (20 kg m-3 crater soil volume) was developed for this specific type of event at NSTR. The 250 kg of PM-10 mass estimated from this experiment is almost seven-times higher than the 36 kg estimated for the environmental assessment (DOE-ID 2007) using available Environmental Protection Agency (EPA 1995) emission factors. This experiment demonstrated that advanced aircraft-mounted instruments operated by

  8. Geochemical and microbiological fingerprinting of airborne dust that fell in Canberra, Australia, in October 2002

    NASA Astrophysics Data System (ADS)

    de Deckker, Patrick; Abed, Raeid M. M.; de Beer, Dirk; Hinrichs, Kai-Uwe; O'Loingsigh, Tadhg; Schefuß, Enno; Stuut, Jan-Berend W.; Tapper, Nigel J.; van der Kaars, Sander

    2008-12-01

    During the night of 22-23 October 2002, a large amount of airborne dust fell with rain over Canberra, located some 200 km from Australia's east coast, and at an average altitude of 650 m. It is estimated that during that night about 6 g m-2 of aeolian dust fell. We have conducted a vast number of analyses to "fingerprint" some of the dust and used the following techniques: grain size analysis; scanning electron microscope imagery; major, trace, and rare earth elemental, plus Sr and Nd isotopic analyses; organic compound analyses with respective compound-specific isotope analyses; pollen extraction to identify the vegetation sources; and molecular cloning of 16S rRNA genes in order to identify dust bacterial composition. DNA analyses show that most obtained 16S rRNA sequences belong mainly to three groups: Proteobacteria (25%), Bacteriodetes (23%), and gram-positive bacteria (23%). In addition, we investigated the meteorological conditions that led to the dust mobilization and transport using model and satellite data. Grain sizes of the mineral dust show a bimodal distribution typical of proximal dust, rather than what is found over oceans, and the bimodal aspect of size distribution confirms wet deposition by rain droplets. The inorganic geochemistry points to a source along/near the Darling River in NW New South Wales, a region that is characteristically semiarid, and both the organic chemistry and palynoflora of the dust confirm the location of this source area. Meteorological reconstructions of the event again clearly identify the area near Bourke-Cobar as being the source of the dust. This study paves the way for determining the export of Australian airborne dust both in the oceans and other continents.

  9. Airborne infrared low level wind shear predictor

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.; Kurkowski, R. L.

    1984-01-01

    The operating principles and test performance of an airborne IR (13-16 micron) temperature-sensing detection and warning system for low-level wind shear (LLWS) are presented. The physics of LLWS phenomena and of the IR radiometer are introduced. The cold density-current outflow or gust front related to LLWS is observed in the IR spectrum of CO2 by a radiometer with + or - 0.5-C accuracy at 0.5-Hz sampling rate; LLWS alerts are given on the basis of specific criteria. Test results from the JAWS experiments conducted at Denver in July 1982, are presented graphically and discussed. The feasibility of the passive IR system is demonstrated, with an average warning time of 51 sec, corresponding to a distance from touchdown of about 2 miles.

  10. Assessing sources of airborne mineral dust and other aerosols, in Iraq

    NASA Astrophysics Data System (ADS)

    Engelbrecht, Johann P.; Jayanty, R. K. M.

    2013-06-01

    Most airborne particulate matter in Iraq comes from mineral dust sources. This paper describes the statistics and modeling of chemical results, specifically those from Teflon® filter samples collected at Tikrit, Balad, Taji, Baghdad, Tallil and Al Asad, in Iraq, in 2006/2007. Methodologies applied to the analytical results include calculation of correlation coefficients, Principal Components Analysis (PCA), and Positive Matrix Factorization (PMF) modeling. PCA provided a measure of the covariance within the data set, thereby identifying likely point sources and events. These include airborne mineral dusts of silicate and carbonate minerals, gypsum and salts, as well as anthropogenic sources of metallic fumes, possibly from battery smelting operations, and emissions of leaded gasoline vehicles. Five individual PMF factors (source categories) were modeled, four of which being assigned to components of geological dust, and the fifth to gasoline vehicle emissions together with battery smelting operations. The four modeled geological components, dust-siliceous, dust-calcic, dust-gypsum, and evaporate occur in variable ratios for each site and size fraction (TSP, PM10, and PM2.5), and also vary by season. In general, Tikrit and Taji have the largest and Al Asad the smallest percentages of siliceous dust. In contrast, Al Asad has the largest proportion of gypsum, in part representing the gypsiferous soils in that region. Baghdad has the highest proportions of evaporite in both size fractions, ascribed to the highly salinized agricultural soils, following millennia of irrigation along the Tigris River valley. Although dust storms along the Tigris and Euphrates River valleys originate from distal sources, the mineralogy bears signatures of local soils and air pollutants.

  11. Chemical speciation of size-segregated floor dusts and airborne magnetic particles collected at underground subway stations in Seoul, Korea.

    PubMed

    Jung, Hae-Jin; Kim, BoWha; Malek, Md Abdul; Koo, Yong Sung; Jung, Jong Hoon; Son, Youn-Suk; Kim, Jo-Chun; Kim, HyeKyoung; Ro, Chul-Un

    2012-04-30

    Previous studies have reported the major chemical species of underground subway particles to be Fe-containing species that are generated from wear and friction processes at rail-wheel-brake and catenaries-pantographs interfaces. To examine chemical composition of Fe-containing particles in more details, floor dusts were collected at five sampling locations of an underground subway station. Size-segregated floor dusts were separated into magnetic and non-magnetic fractions using a permanent magnet. Using X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDX), iron metal, which is relatively harmless, was found to be the dominating chemical species in the floor dusts of the <25 μm size fractions with minor fractions of Mg, Al, Si, Ca, S, and C. From SEM analysis, the floor dusts of the <25 μm size fractions collected on railroad ties appeared to be smaller than 10 μm, indicating that their characteristics should somewhat reflect the characteristics of airborne particles in the tunnel and the platform. As most floor dusts are magnetic, PM levels at underground subway stations can be controlled by removing magnetic indoor particles using magnets. In addition, airborne subway particles, most of which were smaller than 10 μm, were collected using permanent magnets at two underground subway stations, namely Jegi and Yangjae stations, in Seoul, Korea. XRD and SEM/EDX analyses showed that most of the magnetic aerosol particles collected at Jegi station was iron metal, whereas those at Yangjae station contained a small amount of Fe mixed with Na, Mg, Al, Si, S, Ca, and C. The difference in composition of the Fe-containing particles between the two subway stations was attributed to the different ballast tracks used. PMID:22381374

  12. Plasmonic spectra of individual subwavelength particles under the infrared microscope: cells and airborne dust

    NASA Astrophysics Data System (ADS)

    Coe, James V.; Lioi, David B.; Shaffer, Lindsey; Malone, Marvin A.; Luthra, Antriksh; Ravi, Aruna

    2014-03-01

    A plasmonic metal film with a subwavelength hole array (a mesh) is used to capture an individual subwavelength particle, like a single yeast cell or airborne dust particle, and an imaging infrared (IR) microscope, records a scatterfree, IR absorption spectrum of the particle. Individual spectra of wavelength scale particles usually suffer from large scattering effects. This paper starts by demonstrating the plasmonic nature of the mesh in the infrared, proceeds to how this special form of light (surface plasmon polariton mediated transmission resonance) leads to scatter-free IR absorption spectra of individual, subwavelength particles, and ends with work on yeast cells and dust particles from our laboratory air and a household filter.

  13. Airborne dust transport to the eastern Pacific Ocean off southern California: Evidence from San Clemente Island

    NASA Astrophysics Data System (ADS)

    Muhs, Daniel R.; Budahn, James; Reheis, Marith; Beann, Jossh; Skipp, Gary; Fisher, Eric

    2007-07-01

    Islands are natural dust traps, and San Clemente Island, California, is a good example. Soils on marine terraces cut into Miocene andesite on this island are clay-rich Vertisols or Alfisols with vertic properties. These soils are overlain by silt-rich mantles, 5-20 cm thick, that contrast sharply with the underlying clay-rich subsoils. The silt mantles have a mineralogy that is distinct from the island bedrock. Silt mantles are rich in quartz, which is rare in the island andesite. The clay fraction of the silt mantles is dominated by mica, also absent from local andesite, and contrasts with the subsoils, dominated by smectite. Ternary plots of immobile trace elements (Sc-Th-La and Ta-Nd-Cr) show that the island andesite has a composition intermediate between average upper continental crust and average oceanic crust. In contrast, the silt and, to a lesser extent, clay fractions of the silt mantles have compositions closer to average upper continental crust. The silt mantles have particle size distributions similar to loess and Mojave Desert dust, but are coarser than long-range-transported Asian dust. We infer from these observations that the silt mantles are derived from airborne dust from the North American mainland, probably river valleys in the coastal mountains of southern California and/or the Mojave Desert. Although average winds are from the northwest in coastal California, easterly winds occur numerous times of the year when "Santa Ana" conditions prevail, caused by a high-pressure cell centered over the Great Basin. Examination of satellite imagery shows that easterly Santa Ana winds carry abundant dust to the eastern Pacific Ocean and the California Channel Islands. Airborne dust from mainland North America may be an important component of the offshore sediment budget in the easternmost Pacific Ocean, a finding of potential biogeochemical and climatic significance.

  14. Airborne dust transport to the eastern Pacific Ocean off southern California: Evidence from San Clemente Island

    USGS Publications Warehouse

    Muhs, D.R.; Budahn, J.; Reheis, M.; Beann, J.; Skipp, G.; Fisher, E.

    2007-01-01

    Islands are natural dust traps, and San Clemente Island, California, is a good example. Soils on marine terraces cut into Miocene andesite on this island are clay-rich Vertisols or Alfisols with vertic properties. These soils are overlain by silt-rich mantles, 5-20 cm thick, that contrast sharply with the underlying clay-rich subsoils. The silt mantles have a mineralogy that is distinct from the island bedrock. Silt mantles are rich in quartz, which is rare in the island andesite. The clay fraction of the silt mantles is dominated by mica, also absent from local andesite, and contrasts with the subsoils, dominated by smectite. Ternary plots of immobile trace elements (Sc-Th-La and Ta-Nd-Cr) show that the island andesite has a composition intermediate between average upper continental crust and average oceanic crust. In contrast, the silt and, to a lesser extent, clay fractions of the silt mantles have compositions closer to average upper continental crust. The silt mantles have particle size distributions similar to loess and Mojave Desert dust, but are coarser than long-range-transported Asian dust. We infer from these observations that the silt mantles are derived from airborne dust from the North American mainland, probably river valleys in the coastal mountains of southern California and/or the Mojave Desert. Although average winds are from the northwest in coastal California, easterly winds occur numerous times of the year when "Santa Ana" conditions prevail, caused by a high-pressure cell centered over the Great Basin. Examination of satellite imagery shows that easterly Santa Ana winds carry abundant dust to the eastern Pacific Ocean and the California Channel Islands. Airborne dust from mainland North America may be an important component of the offshore sediment budget in the easternmost Pacific Ocean, a finding of potential biogeochemical and climatic significance.

  15. Exposure to airborne microorganisms, dust and endotoxin during flax scutching on farms.

    PubMed

    Krysińska-Traczyk, Ewa; Skórska, Czesława; Prazmo, Zofia; Sitkowska, Jolanta; Cholewa, Grazyna; Dutkiewicz, Jacek

    2004-01-01

    Microbiological air sampling was performed on 5 flax farms located in eastern Poland. Air samples for determination of the concentrations of microorganisms, dust and endotoxin were collected in barns during machine scutching of flax stems by the farmers. The concentrations of mesophilic bacteria ranged from 203.5-698.8 x 10(3) cfu/m3, of Gram-negative bacteria from 27.2-123.4 x 10(3) cfu/m3, of thermophilic actinomycetes from 0.5-2.6 x 10(3) cfu/m3, and of fungi from 23.4-99.8 x 10(3) cfu/m3. The concentrations of total airborne microorganisms (bacteria + fungi) were within a range of 245.0-741.0 x 10(3) cfu/m3. The values of the respirable fraction of total airborne microflora on the examined farms were between 45.5-98.3%. Corynebacteria (irregular Gram-positive rods, mostly Corynebacterium spp.) were dominant at all sampling sites, forming 46.8-67.8% of the total airborne microflora. Among Gram-negative bacteria, the most numerous species was Pantoea agglomerans (synonyms: Erwinia herbicola, Enterobacter agglomerans), known to have strong endotoxic and allergenic properties. Among fungi, the allergenic species Alternaria alternata prevailed. Altogether, 25 species or genera of bacteria and 10 species or genera of fungi were identified in the farm air during flax scutching; of these, 11 and 6 species or genera respectively were reported as having allergenic and/or immunotoxic properties. The concentrations of airborne dust ranged within 43.7-648.1 mg/m3 (median 93.6 mg/m3), exceeding on all farms the Polish OEL value of 4 mg/m3. The concentrations of airborne endotoxin ranged within 16.9-172.1 microg/m3 (median 30.0 microg/m3), exceeding at all sampling sites the suggested OEL value of 0.2 microg/m). In conclusion, flax farmers performing machine scutching of flax could be exposed to large concentrations of airborne microorganisms, dust and endotoxin, posing a risk of work-related respiratory disease. PMID:15627342

  16. Airborne and Grain Dust Fungal Community Compositions Are Shaped Regionally by Plant Genotypes and Farming Practices.

    PubMed

    Pellissier, Loïc; Oppliger, Anne; Hirzel, Alexandre H; Savova-Bianchi, Dessislava; Mbayo, Guilain; Mascher, Fabio; Kellenberger, Stefan; Niculita-Hirzel, Hélène

    2016-04-01

    Chronic exposure to airborne fungi has been associated with different respiratory symptoms and pathologies in occupational populations, such as grain workers. However, the homogeneity in the fungal species composition of these bioaerosols on a large geographical scale and the different drivers that shape these fungal communities remain unclear. In this study, the diversity of fungi in grain dust and in the aerosols released during harvesting was determined across 96 sites at a geographical scale of 560 km(2) along an elevation gradient of 500 m by tag-encoded 454 pyrosequencing of the internal transcribed spacer (ITS) sequences. Associations between the structure of fungal communities in the grain dust and different abiotic (farming system, soil characteristics, and geographic and climatic parameters) and biotic (wheat cultivar and previous crop culture) factors were explored. These analyses revealed a strong relationship between the airborne and grain dust fungal communities and showed the presence of allergenic and mycotoxigenic species in most samples, which highlights the potential contribution of these fungal species to work-related respiratory symptoms of grain workers. The farming system was the major driver of the alpha and beta phylogenetic diversity values of fungal communities. In addition, elevation and soil CaCO3 concentrations shaped the alpha diversity, whereas wheat cultivar, cropping history, and the number of freezing days per year shaped the taxonomic beta diversity of these communities. PMID:26826229

  17. Effect of electrostatic charge on the aspiration efficiencies of airborne dust samplers: with special reference to asbestos

    SciTech Connect

    Johnston, A.M.; Jones, A.D.; Vincent, J.H.

    1987-07-01

    An experimental investigation has been conducted into the effects of electrostatic charge, carried by the dust particles and by the sampler itself, on the sampling of airborne dusts. Experiments covering both personal and static sampling and a range of sampler types were carried out in the laboratory for both fibrous asbestos and isometric silica gel dusts. Experiments also were carried out in the spinning shop of an asbestos textile factory. The results showed that the aspiration efficiency of the sampler always is reduced as the charge on the sampler increases, independently of the type of sampler and of whether it is used as a static or personal sampler. The effect is most marked when sampling takes place in calm air. It is concluded from the results that, for the levels of charge reached by samplers in most practical situations, the effects on aspiration efficiency will be small. Possible exceptions to this might occur, however, in workplace environments where relative humidity is very low, and charge levels of the sampler (or on the worker wearing the sampler) can become high.

  18. The effect of electrostatic charge on the aspiration efficiencies of airborne dust samplers: with special reference to asbestos.

    PubMed

    Johnston, A M; Jones, A D; Vincent, J H

    1987-07-01

    An experimental investigation has been conducted into the effects of electrostatic charge, carried by the dust particles and by the sampler itself, on the sampling of airborne dusts. Experiments covering both personal and static sampling and a range of sampler types were carried out in the laboratory for both fibrous asbestos and isometric silica gel dusts. Experiments also were carried out in the spinning shop of an asbestos textile factory. The results showed that the aspiration efficiency of the sampler always is reduced as the charge on the sampler increases, independently of the type of sampler and of whether it is used as a static or personal sampler. The effect is most marked when sampling takes place in calm air. It is concluded from the results that, for the levels of charge reached by samplers in most practical situations, the effects on aspiration efficiency will be small. Possible exceptions to this might occur, however, in workplace environments where relative humidity is very low, and charge levels of the sampler (or on the worker wearing the sampler) can become high. PMID:3039822

  19. Long-term airborne contamination studied by attic dust in an industrial area: Ajka, Hungary

    NASA Astrophysics Data System (ADS)

    Völgyesi, P.; Jordan, G.; Szabo, Cs.

    2012-04-01

    Heavy industrial activities such as mining, metal industry, coal fired power plants have produced large amount of by-products and wide-spread pollution, particularly in the period of centrally dictated economy after WWII, in Hungary. Several studies suggest that significant amount of these pollutants have been deposited in the urban environment. Nowadays, more than half of the world's population is living in urban areas and people spend almost 80% of their lives indoors in developed countries increasing human health risk due to contamination present in urban dwellings. Attic dust sampling was applied to determine the long-term airborne contamination load in the industrial town of Ajka (Hungary). There has been a high industrial activity in Ajka since the end of the 19th century. In addition to aluminum and alumina industry, coal mining, coal fired power plant and glass industry sites, generated numerous waste heaps which act as multi-contamination sources in the area. In October 2010 the Ajka red mud tailings pond failed and caused an accidental regional contamination of international significance. The major objective of this research was to study and map the spatial distribution of heavy metal contamination in airborne attic dust samples. At 27 sampling sites 30 attic dust samples were collected. Sampling strategy followed a grid-based stratified random sampling design. In each cell a house for attic dust sample collection was selected that was located the closest to a randomly generated point in the grid cell. The project area covers a 8x8 grid of 1x1 km cells with a total area of 64 km2. In order to represent long-term industrial pollution, houses with attics kept intact for at least 30-40 years were selected for sampling. Sampling included the collection of background samples remotely placed from the industrialized urban area. The concentration of the major and toxic elements (Al, Ca, Fe, K, Mg, Mn, Na, P, S, and As, Ba, Cd, Co, Cr, Cu, Li, Mo, Ni, Pb, Se, Sn

  20. Geltape method for measurement of work related surface contamination with cobalt containing dust: correlation between surface contamination and airborne exposure.

    PubMed Central

    Poulsen, O M; Olsen, E; Christensen, J M; Vinzent, P; Petersen, O H

    1995-01-01

    OBJECTIVES--The geltape method is a new method for optical measurement of total amount of dust on surfaces. The objectives were to study the potential applicability of this method to measurements of work related cobalt exposure during painting of plates with cobalt dye. METHODS--Consecutive series of work related geltape prints were taken from surfaces inside and outside the ventilation cabins of two plate painters during two full working days. The amount of dust picked up by the geltapes was measured optically with a field monitor. Also, personal air samples were collected on filters at the different work processes. In the laboratory the contents of cobalt on the geltape prints and the filters were measured with inductive coupled plasma atomic emission spectroscopy. RESULTS--The key results were: (a) when the geltape prints were taken from surfaces inside the cabins the optically measured area of the geltapes covered with total dust (area (%)) correlated well with the chemically measured amount of cobalt present on the geltapes. Linear correlation coefficient (R2) was 0.91 for geltape prints taken on the floor and 0.94 for prints taken on the ceiling; (b) the cumulative airborne cobalt exposure, calculated from data on work related exposure by personal sampling, correlated with the area (%) of geltape prints taken from the ceiling of the cabin (R2 = 0.98); (c) the geltape method could be used to distinguish both between work processes with different levels of cobalt exposure, and between plate painters subjected to significant differences in airborne cobalt exposure. CONCLUSION--The geltape method could produce measures of the work related exposures as well as whole day exposure for cobalt. The geltape results correlated with measurements of personal airborne cobalt exposure. In this industry the profile of exposure is well-defined in time, and it seems reasonable to apply this fast and low cost method in routine exposure surveillance to obtain a more detailed

  1. Impact of Direct Soil Exposures from Airborne Dust and Geophagy on Human Health

    PubMed Central

    Sing, David; Sing, Charles F

    2010-01-01

    Over evolutionary time humans have developed a complex biological relationship with soils. Here we describe modes of soil exposure and their biological implications. We consider two types of soil exposure, the first being the continuous exposure to airborne soil, and the second being dietary ingestion of soils, or geophagy. It may be assumed that airborne dust and ingestion of soil have influenced the evolution of particular DNA sequences which control biological systems that enable individual organisms to take advantage of, adapt to and/or protect against exposures to soil materials. We review the potential for soil exposure as an environmental source of epigenetic signals which may influence the function of our genome in determining health and disease. PMID:20617027

  2. Effect of ultraviolet on the survival of bacteria airborne in simulated Martian dust clouds.

    PubMed

    Hagen, C A; Hawrylewicz, E J; Anderson, B T; Cephus, M L

    1970-01-01

    A chamber was constructed to create simulated Martian dust storms and thereby study the survival of airborne micro-organisms while exposed to the rigors of the Martian environment, including ultraviolet irradiation. Representative types of sporeforming and non-sporeforming bacteria present in spacecraft assembly areas and indigenous to humans were studied. It was found that daily ultraviolet irradiation of 2 to 9 X 10(7) erg cm-2 was not sufficient to sterilize the dust clouds. The soil particles protected the organisms from ultraviolet irradiation since the numbers of survivors from irradiated environments were similar to those from unirradiated environments. Pending further data of the Martian environment, the contamination and dissemination of Mars with terrestrial micro-organisms is still a distinct possibility. PMID:12664918

  3. Machine vision based particle size and size distribution determination of airborne dust particles of wood and bark pellets

    SciTech Connect

    Igathinathane, C; Pordesimo, L.O.

    2009-08-01

    Dust management strategies in industrial environment, especially of airborne dust, require quantification and measurement of size and size distribution of the particles. Advanced specialized instruments that measure airborne particle size and size distribution apply indirect methods that involve light scattering, acoustic spectroscopy, and laser diffraction. In this research, we propose a simple and direct method of airborne dust particle dimensional measurement and size distribution analysis using machine vision. The method involves development of a user-coded ImageJ plugin that measures particle length and width and analyzes size distribution of particles based on particle length from high-resolution scan images. Test materials were airborne dust from soft pine wood sawdust pellets and ground pine tree bark pellets. Subsamples prepared by dividing the actual dust using 230 mesh (63 m) sieve were analyzed as well. A flatbed document scanner acquired the digital images of the dust particles. Proper sampling, layout of dust particles in singulated arrangement, good contrast smooth background, high resolution images, and accurate algorithm are essential for reliable analysis. A halo effect around grey-scale images ensured correct threshold limits. The measurement algorithm used Feret s diameter for particle length and pixel-march technique for particle width. Particle size distribution was analyzed in a sieveless manner after grouping particles according to their distinct lengths, and several significant dimensions and parameters of particle size distribution were evaluated. Results of the measurement and analysis were presented in textual and graphical formats. The developed plugin was evaluated to have a dimension measurement accuracy in excess of 98.9% and a computer speed of analysis of <8 s/image. Arithmetic mean length of actual wood and bark pellets airborne dust particles were 0.1138 0.0123 and 0.1181 0.0149 mm, respectively. The airborne dust particles of

  4. Assessment of Korean farmer's exposure level to dust in pig buildings.

    PubMed

    Kim, Ki Youn; Ko, Han Jong; Kim, Yoon Shin; Kim, Chi Nyon

    2008-01-01

    The purpose of the study was to assess Korean farmer's exposure level to dust in pig buildings and dust emissions by investigating airborne concentrations of total and respirable dust. Five main types of pig buildings operating currently in Korea were selected. For area air sampling, 30 sites per each building type were visited during spring (March-May) and autumn (September-November) seasons. For personal air sampling, concentrations of total and respirable dust were measured for 2-3 hours, during cleaning the pig building before the end of the daily shift, by attaching air sampling equipment near to the farmer's breathing zone. Measurement were taken for 8 hours, e.g. average daily work time (09:00-17:00), at 0.5 m above the floor at three locations on the central alley in the pig building. Emission rates of total and respirable dust were estimated by multiplying the mean concentration of total and respirable dust measured near the air outlet by the mean ventilation rate, and expressed either per area or per pig of live weight. The ranges of farmer's exposure level to total dust and respirable dust in the pig buildings were estimated as 0.6-6.7 mg m(-3) and 0.3-3.5 mg m(-3), respectively. The pig buildings operated with a deep-litter bed system showed the highest dust level while the naturally ventilated pig buildings with slats represented the lowest dust level (p<0.05). Emission rates ranged from 35-400 mg h(-1) m(-2) for total dust and from 4-40 mg h(-1) m(-2) for respirable dust, respectively, indicating a similar pattern for the distribution of exposure level. Korean farmers' exposure level to dust in all the pig buildings investigated was below the exposure limit value equal in Korea equal to 10 mg m(-3), while it exceeded the threshold limit values (TLVs) established in other developed countries. In comparison with previous studies performed in other countries, mean exposure level in the pig buildings of Korea was generally lower for total dust and higher

  5. Airborne Sunphotometry of African Dust and Marine Boundary Layer Aerosols in PRIDE

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Redemann, Jens; Russell, Philip; Schmid, Beat; Reid, Jeff; Pilewskie, Peter; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    The Puerto Rico Dust Experiment (PRIDE) was conducted during summer 2000 to study the radiative, microphysical and transport properties of Saharan dust in the Caribbean region. During PRIDE, NASA Ames Research Center's six-channel airborne autotracking sunphotometer (AATS-6) was operated aboard a Piper Navajo airplane based at Roosevelt Roads Naval Station on the northeast coast of Puerto Rico. AATS-6 measurements were taken during 21 science flights off the coast of Puerto Rico in the western Caribbean. Data were acquired within and above the Marine Boundary Layer (MBL) and the Saharan Aerosol Layer (SAL) up to 5.5 km altitude tinder a wide range of dust loadings. Aerosol optical depth (AOD) spectra and columnar water vapor (CWV) values have been calculated from the AATS-6 measurements by using sunphotometer calibration data obtained at Mauna Loa Observatory (3A kin ASL) before (May) and after (October) PRIDE. Mid-visible AOD values measured near the surface during PRIDE ranged from 0.07 on the cleanest day to 0.55 on the most turbid day. Values measured above the MBL were as high as 0.35; values above the SAL were as low as 0.01. The fraction of total column AOD due to Saharan dust cannot be determined precisely from AATS-6 AOD data alone due to the uncertainty in the extent of vertical mixing of the dust down through the MBL. However, analyses of ground-based and airborne in-situ aerosol sampling measurements and ground-based aerosol lidar backscatter data should yield accurate characterization of the vertical mixing that will enable calculation of the Saharan dust AOD component from the sunphotometer data. Examples will be presented showing measured AATS-6 AOD spectra, calculated aerosol extinction and water vapor density vertical profiles, and aerosol size distributions retrieved by inversion of the AOD spectra. Near sea-surface AOD spectra acquired by AATS-6 during horizontal flight legs at 30 m ASL are available for validation of AOD derived from coincident

  6. Waveband selection within 400-4000  cm-1 of optical identification of airborne dust in coal mine tunneling face.

    PubMed

    Wang, Wenzheng; Wang, Yanming; Shi, Guoqing

    2016-04-10

    Aimed at the optical evaluation of pollution levels caused by rock dust in an underground coal mine tunneling face, the optimal detection line and optical channel were investigated. The spatial distribution of airborne rock dust under local mining and ventilation conditions was simulated by the computational fluid dynamics method; thus, combined with the scattering and absorption properties of dust particles and gas molecules, the spectral transmission characteristics of a polluted atmosphere, including dust aerosols within 400-4000  cm-1, were obtained. By eliminating the optical background of mine gases, the pure infrared signals of rock dust were further analyzed. Based on the comparison results, the detection line, which is 1.5 m high and 0.3 m away from the right wall, was determined to be the best observation position, and a waveband of 1505-1525  cm-1 was selected to estimate the dust concentration. In addition, a dual-band detection method was presented, which can simultaneously identify the dust distribution and dispersion. PMID:27139859

  7. Metal and Metalloid Contaminants in Airborne Dust Associated with Mining Operations

    NASA Astrophysics Data System (ADS)

    Betterton, E. A.; Csavina, J. L.; Field, J. P.; Landázuri, A. C.; Felix Villar, O.; Rine, K. P.; Sáez, A.; Pence, J.; Shayan, H.; Russell, M.

    2011-12-01

    Mining operations are potential sources of airborne 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, with potential deleterious effects on human health and ecology. In this work, we report the size-resolved chemical characterization of atmospheric aerosols sampled near an inactive Superfund site and at an active mining and smelting site in Arizona. Aerosols were characterized with 10-stage (0.054 to 18 μm aerodynamic diameter) multiple orifice uniform deposit impactors (MOUDI), Dustrack monitors, and total suspended particulate (TSP) collectors. The MOUDI results show that arsenic and lead concentrations follow a bimodal distribution, with maxima centered at approximately 0.3 and 7.0 μm aerodynamic diameter. We hypothesize that the sub-micron arsenic and lead are the product of condensation and coagulation of smelting vapors. In the coarse size, contaminants are thought to originate as aeolian dust from mine tailings and other sources.

  8. Heavy Metal Content in Airborne Dust of Childhood Leukemia Cluster Areas: Even Small Towns Have Air Pollutants

    NASA Astrophysics Data System (ADS)

    Sheppard, P. R.; Witten, M. L.

    2004-12-01

    Currently in the US, there are at least two ongoing clusters of childhood leukemia, where the incidence rate over the last several years has exceeded the national norm. In Fallon, Nevada, a town of 8,000 people, 16 children have been diagnosed with leukemia since 1995, three of whom have died. In Sierra Vista, Arizona, a town of 38,000 people, 12 children have been diagnosed since 1998, two of whom have died. A possible third cluster of childhood leukemia and other cancers is being monitored in Elk Grove, California, a suburb of Sacramento. For the purpose of characterizing the heavy metal content of airborne dust of these three communities, total suspended particulate samples were collected from each town as well as from nearby towns that could be considered as control comparisons. Sampling was done using portable high-volume blowers and glass- or quartz-fiber filter media. Filters were measured for elemental concentrations using inductively coupled plasma mass spectroscopy. To date, our most notable results are from the Nevada region. Compared to other control towns in the region, Fallon had significantly more tungsten in its airborne dust. Uranium was also higher in dust of Fallon than in other control towns. Uranium is a known health hazard, though it is not necessarily specifically related to childhood leukemia. The role of tungsten in childhood leukemia has not been widely studied. However, other research has identified tungsten exposure as an environmental concern in Fallon. A CDC study of human tissue samples from Fallon has shown high tungsten levels in people of Fallon, and a USGS study of drinking water in Fallon also has shown high tungsten there. Tree-ring research on selected trees has shown high tungsten values in recent rings compared to earlier rings. While these multiple indications of tungsten in the Fallon environment do not directly lead to the conclusion that tungsten causes leukemia, they do combine to suggest that biomedical research on the

  9. A 15-week experimental exposure of pigs to airborne dust with added endotoxin in a continuous flow exposure chamber.

    PubMed Central

    Jolie, R; Bäckström, L; Olson, L; Chase, C

    1999-01-01

    The purpose of this study was to evaluate the effect of longterm exposure to airborne dust and endotoxin on the respiratory system of pigs. A continuous flow exposure chamber was built for the purpose of exposing pigs to selected airborne contaminants. Pigs (n = 6) were exposed to a combination of a very fine corn/soybean meal (40.6 mg/m3) with added lipopolysaccharide (LPS; 12.4 microg/m3) for 8 h/d over 5 d for 15 wk (75 d of exposure). Control pigs (n = 6) were housed in a room with minimal contamination of these airborne contaminants. Surprisingly, dust in the exposure chamber and the control room was highly contaminated with peptidoglycan. Changes in the lung were monitored by collecting bronchoalveolar lavage (BAL) fluid for cytology at 5 different time points throughout the exposure period. Blood samples were collected at the same time for hematology. A non-specific respiratory inflammatory response was found in exposed and control pigs, as suggested by the increased neutrophils in BAL fluid and the small inflammatory areas in the lung tissue. No macroscopic lung lesions were observed in control or exposed pigs. The findings in the control pigs imply that even low dust concentrations and possibly peptidoglycan contamination can induce cellular changes in the BAL fluid and that a true control pig does not exist. In addition, the exposed pigs developed a mild eosinophilia, indicating an allergic response to the airborne contaminants. PMID:10369571

  10. Geochemical evidence for airborne dust additions to soils in Channel Islands National Park, California

    USGS Publications Warehouse

    Muhs, D.R.; Budahn, J.R.; Johnson, D.L.; Reheis, M.; Beann, J.; Skipp, G.; Fisher, E.; Jones, J.A.

    2008-01-01

    There is an increasing awareness that dust plays important roles in climate change, biogeochemical cycles, nutrient supply to ecosystems, and soil formation. In Channel Islands National Park, California, soils are clay-rich Vertisols or Alfisols and Mollisols with vertic properties. The soils are overlain by silt-rich mantles that contrast sharply with the underlying clay-rich horizons. Silt mantles contain minerals that are rare or absent in the volcanic rocks that dominate these islands. Immobile trace elements (Sc-Th-La and Ta-Nd-Cr) and rare-earth elements show that the basalt and andesite on the islands have a composition intermediate between upper-continental crust and oceanic crust. In contrast, the silt fractions and, to a lesser extent, clay fractions of the silt mantle have compositions closer to average upper-continental crust and very similar to Mojave Desert dust. Island shelves, exposed during the last glacial period, could have provided a source of eolian sediment for the silt mantles, but this is not supported by mineralogical data. We hypothesize that a more likely source for the silt-rich mantles is airborne dust from mainland California and Baja California, either from the Mojave Desert or from the continental shelf during glacial low stands of sea. Although average winds are from the northwest in coastal California, easterly winds occur numerous times of the year when "Santa Ana" conditions prevail, caused by a high-pressure cell centered over the Great Basin. The eolian silt mantles constitute an important medium of plant growth and provide evidence that abundant eolian silt and clay may be delivered to the eastern Pacific Ocean from inland desert sources. ?? 2007 Geological Society of America.

  11. Separating Dust Mixtures and Other External Aerosol Mixtures Using Airborne High Spectral Resolution Lidar Data

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Ferrare, R. A.; Vaughan, M.; Hostetler, C. A.; Rogers, R. R.; Hair, J. W.; Cook, A. L.; Harper, D. B.

    2013-12-01

    Knowledge of aerosol type is important for source attribution and for determining the magnitude and assessing the consequences of aerosol radiative forcing. The NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) has acquired considerable datasets of both aerosol extensive parameters (e.g. aerosol optical depth) and intensive parameters (e.g. aerosol depolarization ratio, lidar ratio) that can be used to infer aerosol type. An aerosol classification methodology has been used extensively to classify HSRL-1 aerosol measurements of different aerosol types including dust, smoke, urban pollution, and marine aerosol. However, atmospheric aerosol is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the aerosol. Here we present a comprehensive and unified set of rules for characterizing external mixtures using several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e. lidar ratio), backscatter color ratio, and depolarization ratio. Our mixing rules apply not just to the scalar values of aerosol intensive parameters, but to multi-dimensional normal distributions with variance in each measurement dimension. We illustrate the applicability of the mixing rules using examples of HSRL-1 data where mixing occurred between different aerosol types, including advected Saharan dust mixed with the marine boundary layer in the Caribbean Sea and locally generated dust mixed with urban pollution in the Mexico City surroundings. For each of these cases we infer a time-height cross section of mixing ratio along the flight track and we partition aerosol extinction into portions attributed to the two pure types. Since multiple aerosol intensive parameters are measured and included in these calculations, the techniques can also be used for cases without significant depolarization (unlike similar work by earlier researchers), and so a third example of a

  12. Models for forecasting airborne Cupressaceae pollen levels in central Spain

    NASA Astrophysics Data System (ADS)

    Sabariego, Silvia; Cuesta, Pedro; Fernández-González, Federico; Pérez-Badia, Rosa

    2012-03-01

    The influence of meteorological variables on airborne Cupressaceae pollen levels in central Spain was analyzed, and prediction models based on polynomial and multiple regressions were used to predict pollen counts throughout the pollen season. The Cupressaceae pollen type was selected in view of both its abundance in the atmosphere of the central Iberian Peninsula (particularly from January to March) and its allergenic importance. Sampling was performed uninterruptedly over a 5-year period, using a Hirst volumetric sampler and the sampling method established by the Spanish Aerobiology Network. Temperature displayed the strongest (positive) correlation with Cupressaceae pollen counts. Polynomial and multiple regression analysis showed that maximum temperature was the most influential variable included in prediction models. The prediction equations obtained for the study period were reasonably satisfactory, accounting for 48% and 59% of the variation in airborne pollen levels.

  13. Investigation of the degree of equilibrium of the long-lived uranium-238 decay-chain members in airborne and bulk uranium-ore dusts

    SciTech Connect

    Jackson, P.O.; Thomas, C.W.

    1982-08-01

    The degree of disequilibrium among /sup 238/U decay chain members in some airborne dusts and typical ores has been established by precise radiochemical analyses. This information is necessary to evaluate the lung dose model currently used for estimating the effect of the inhalation of uranium ore dust. The particle size distributions of airborne decay chain components in dusts at one uranium mill have been investigated. Statistically significant disequilibria were observed for /sup 230/Th, /sup 226/Ra, and /sup 210/Pb in both airborne dusts and composite ore samples. With the exception of ore from one mill in the United States, most of the daughter concentrations in powdered ore composites were within 10% of /sup 238/U. In airborne dusts, the concentration of /sup 226/Ra was typically below /sup 238/U; the minimum /sup 226/Ra concentration observed for airborne ore dusts was 56% of equilibrium. A statistically significant particle size dependence was observed for /sup 226/Ra//sup 238/U ratios in several airborne dusts collected at a uranium mill.

  14. Impact of ferromanganese alloy plants on household dust manganese levels: implications for childhood exposure.

    PubMed

    Lucas, E L; Bertrand, P; Guazzetti, S; Donna, F; Peli, M; Jursa, T P; Lucchini, R; Smith, D R

    2015-04-01

    Adolescents living in communities with ferromanganese alloy plant activity have been shown to exhibit deficits in olfactory and fine motor function. Household dust may serve as an important manganese (Mn) exposure pathway to children, though dust Mn concentrations have not previously been measured to assess household contamination from ferromanganese alloy plant emissions. Here we determined the association between dust concentrations and surface loadings of Mn and other metals (Al, Cd, Cr, Cu, Fe, Pb, and Zn) in indoor and outdoor household dust from three Italian communities that differ by history of ferromanganese alloy plant activity: Bagnolo Mella, with an active ferromanganese alloy plant (n=178 households); Valcamonica, with historically active plants (n=166); and Garda Lake, with no history of ferromanganese plant activity (n=99). We also evaluated Mn levels in other environmental (soil, airborne particulates) and candidate biomarker (blood, hair, saliva, fingernails) samples from children within the households. Household dust Mn concentrations and surface loadings were significantly different between the three sites, with levels highest in Bagnolo Mella (outdoor median Mn concentration=4620, range 487-183,000µg/g), intermediate in Valcamonica (median=876, range 407-8240µg/g), and lowest in Garda Lake (median=407, range 258-7240µg/g). Outdoor dust Mn concentrations in Bagnolo Mella, but not the other communities, were significantly inversely related with distance from the plant (R(2)=0.6630, P<0.0001). Moreover, outdoor dust Mn concentrations and loadings were highly predictive of but significantly higher than indoor dust Mn concentrations and loadings by ~2 to ~7-fold (Mn concentrations) and ~7 to ~20-fold (Mn loadings). Finally, both indoor and outdoor dust Mn concentrations and outdoor dust Mn loading values were highly significantly correlated with both soil and air Mn concentrations, and with children's hair and fingernail Mn concentrations, but

  15. Impact of Ferromanganese Alloy Plants on Household Dust Manganese Levels: Implications for Childhood Exposure

    PubMed Central

    Lucas, E.L.; Bertrand, P.; Guazzetti, S.; Donna, F.; Peli, M.; Jursa, T.R.; Lucchini, R.; Smith, D.R.

    2015-01-01

    Adolescents living in communities with ferromanganese alloy plant activity have been shown to exhibit deficits in olfactory and fine motor function. Household dust may serve as an important manganese (Mn) exposure pathway to children, though dust Mn concentrations have not previously been measured to assess household contamination from ferromanganese alloy plant emissions. Here we determined the association between dust concentrations and surface loadings of Mn and other metals (Al, Cd, Cr, Cu, Fe, Pb, and Zn) in indoor and outdoor household dust from three Italian communities that differ by history of ferromanganese alloy plant activity: Bagnolo Mella, with an active ferromanganese alloy plant (n=178 households); Valcamonica, with historically active plants (n=166); and Garda Lake, with no history of ferromanganese plant activity (n=99). We also evaluated Mn levels in other environmental (soil, airborne particulates) and candidate biomarker (blood, hair, saliva, fingernails) samples from children within the households. Household dust Mn concentrations and surface loadings were significantly different between the three sites, with levels highest in Bagnolo Mella (outdoor median Mn concentration = 4620, range 487 – 183,000 µg/g), intermediate in Valcamonica (median = 876, range 407 – 8240 µg/g), and lowest in Garda Lake (median = 407, range 258 – 7240 µg/g). Outdoor dust Mn concentrations in Bagnolo Mella, but not the other communities, were significantly inversely related with distance from the plant (R2=0.6630, P<0.0001). Moreover, outdoor dust Mn concentrations and loadings were highly predictive of but significantly higher than indoor dust Mn concentrations and loadings by ~2 to ~7-fold (Mn concentrations) and ~7 to ~20-fold (Mn loadings). Finally, both indoor and outdoor dust Mn concentrations and outdoor dust Mn loading values were highly significantly correlated with both soil and air Mn concentrations, and with children’s hair and fingernail Mn

  16. Dust Transport Across the Atlantic Studied by Airborne Doppler Wind Lidar During the Saltrace Experiment in 2013

    NASA Astrophysics Data System (ADS)

    Chouza, Fernando; Reitebuch, Oliver; Rahm, Stephan; Weinzierl, Bernadett

    2016-06-01

    During the SALTRACE field experiment, conducted during June/July 2013, the Saharan dust transport across the Atlantic was analyzed by a set of ground based, in-situ and airborne instruments, including a 2-μm coherent DWL (Doppler wind lidar) mounted onboard the DLR Falcon 20 research aircraft. An overview of the measurements of aerosol backscatter and extinction, horizontal and vertical winds retrieved from the DWL are presented together with a brief description of the applied methods. The retrieved measurements provide direct observation of Saharan dust transport mechanisms across the Atlantic as well as island induced lee waves in the Barbados region.

  17. Airborne asbestos levels in non-occupational environments in Japan.

    PubMed

    Kohyama, N

    1989-01-01

    Airborne asbestos levels in non-occupational environments in Japan were determined by analytical transmission electron microscopy (ATEM) for about 100 air samples from various outdoor settings. Asbestos fibres (chrysotile) were found in almost all samples. The fibre (mass) concentrations were in the range of 4-367 fibres per litre (0.02-47.2 ng/m3) with a geometric mean of 18 f/1 (0.3 ng/m3). The mass concentrations were similar to the earlier data reported from other countries. Samples from main roads showed extremely high asbestos concentrations and short fibre lengths compared with those of the other samples. This strongly suggested that braking of vehicles was a significant emission source of airborne asbestos. Laboratory experiments using a brake testing machine demonstrated that asbestos fibres were released during braking. In addition, the present study found high levels of airborne asbestos in some highly polluted areas, such as a serpentine quarry, a town adjacent to an asbestos mine, and factories making asbestos slate-board. On the other hand, chrysotile fibres were also found in air samples from a small isolated island in the Pacific Ocean as well as in ice samples from ten thousand years ago in Antarctica. These facts suggest that chrysotile fibres have been liberated both by industrial activities and natural weathering, and have circulated around the earth. PMID:2744826

  18. Factors Affecting Vegetable Growers’ Exposure to Fungal Bioaerosols and Airborne Dust

    PubMed Central

    Hansen, Vinni M.; Meyling, Nicolai Vitt; Winding, Anne; Eilenberg, Jørgen; Madsen, Anne Mette

    2012-01-01

    We have quantified vegetable growers’ exposure to fungal bioaerosol components including (1→3)-β-d-glucan (β-glucan), total fungal spores, and culturable fungal units. Furthermore, we have evaluated factors that might affect vegetable growers’ exposure to fungal bioaerosols and airborne dust. Investigated environments included greenhouses producing cucumbers and tomatoes, open fields producing cabbage, broccoli, and celery, and packing facilities. Measurements were performed at different times during the growth season and during execution of different work tasks. Bioaerosols were collected with personal and stationary filter samplers. Selected fungal species (Beauveria spp., Trichoderma spp., Penicillium olsonii, and Penicillium brevicompactum) were identified using different polymerase chain reaction-based methods and sequencing. We found that the factors (i) work task, (ii) crop, including growth stage of handled plant material, and (iii) open field versus greenhouse significantly affected the workers’ exposure to bioaerosols. Packing of vegetables and working in open fields caused significantly lower exposure to bioaerosols, e.g. mesophilic fungi and dust, than harvesting in greenhouses and clearing of senescent greenhouse plants. Also removing strings in cucumber greenhouses caused a lower exposure to bioaerosols than harvest of cucumbers while removal of old plants caused the highest exposure. In general, the exposure was higher in greenhouses than in open fields. The exposures to β-glucan during harvest and clearing of senescent greenhouse plants were very high (median values ranging between 50 and 1500 ng m−3) compared to exposures reported from other occupational environments. In conclusion, vegetable growers’ exposure to bioaerosols was related to the environment, in which they worked, the investigated work tasks, and the vegetable crop. PMID:22003240

  19. Wind barriers suppress fugitive dust and soil-derived airborne particles in arid regions

    SciTech Connect

    Grantz, D.A.; Vaughn, D.L.; Farber, R.J.; Kim, B.; Ashbaugh, L.; Van Curen, T.; Campbell, R.

    1998-07-01

    Areas of abandoned agricultural land in the Antelope Valley, western Mojave (high) desert of California have proven in the previous studies to be recalcitrant to conventional tillage and revegetation strategies designed to suppress wind erosion of soil and transport of sediment and fugitive dust. These areas represented a continuing source of drifting sand and of coarse and respirable suspended particulate matter. The traditional techniques failed because furrows collapsed and the water holding capacity of the overburden was too low to support seed germination and transplant survival. In this study a variety of wind barriers were evaluated for suppression of sediment transport. Airborne particles were measured with an array of coarse particle samplers at heights of 0.2, 1.0, and 2.0 m above the soil surface. Discrete artificial wind barriers, consisting of widely spaced roughness elements were effective in suppressing fugitive emissions. Wind fences established along the leeward edge of an area of blowing sand, perpendicular to the prevailing wind, significantly decreased fugitive emissions. Control was greatest and precision of the measurements was highest under high wind conditions. These techniques provide rapid and effective suppression of fugitive emissions of soil-derived particles under conditions that resist conventional tillage and revegetation techniques. A simple, indirect procedure for determining local wind velocity erosion thresholds requiring only sampling of wind run and suspended particulate mass compared favorably with direct measurement of saltation as a function of wind velocity.

  20. Bioprocess of Kosa bioaerosols: effect of ultraviolet radiation on airborne bacteria within Kosa (Asian dust).

    PubMed

    Kobayashi, Fumihisa; Maki, Teruya; Kakikawa, Makiko; Yamada, Maromu; Puspitasari, Findya; Iwasaka, Yasunobu

    2015-05-01

    Kosa (Asian dust) is a well-known weather phenomenon in which aerosols are carried by the westerly winds from inland China to East Asia. Recently, the frequency of this phenomenon and the extent of damage caused have been increasing. The airborne bacteria within Kosa are called Kosa bioaerosols. Kosa bioaerosols have affected ecosystems, human health and agricultural productivity in downwind areas. In order to develop a new and useful bacterial source and to identify the source region of Kosa bioaerosols, sampling, isolation, identification, measurement of ultraviolet (UV) radiation tolerance and experimental simulation of UV radiation conditions were performed during Kosa bioaerosol transportation. We sampled these bioaerosols using a Cessna 404 airplane and a bioaerosol sampler at an altitude of approximately 2900 m over the Noto Peninsula on March 27, 2010. The bioaerosol particles were isolated and identified as Bacillus sp. BASZHR 1001. The results of the UV irradiation experiment showed that the UV radiation tolerance of Kosa bioaerosol bacteria was very high compared with that of a soil bacterium. Moreover, the UV radiation tolerance of Kosa bioaerosol spores was higher than that of soil bacterial spores. This suggested that Kosa bioaerosols are transported across the atmosphere as living spores. Similarly, by the experimental simulation of UV radiation conditions, the limited source region of this Kosa bioaerosol was found to be southern Russia and there was a possibility of transport from the Kosa source area. PMID:25735592

  1. Optimization of the concentration optics of the Martian airborne dust sensor for MetNet space mission

    NASA Astrophysics Data System (ADS)

    Cortés, F.; González, A.; de Castro, A. J.; López, F.

    2012-06-01

    Martian atmosphere contains a significant and rapidly changing load of suspended dust that never drops to zero. The main component of Martian aerosol is micron-sized dust thought to be a product of soil weathering. Although airborne dust plays a key role in Martian climate, the basic physical properties of these aerosols are still poorly known. The scope of Mars MetNet Mission is to deploy several tens of mini atmospheric stations on the Martian surface. MEIGA-MetNet payload is the Spanish contribution in MetNet. Infrared Laboratory of University Carlos III (LIR-UC3M) is in charge of the design and development of a micro-sensor for the characterization of airborne dust. This design must accomplish with a strict budget of mass and power, 45 g and 1 W respectively. The sensor design criteria have been obtained from a physical model specifically developed for optimizing IR local scattering. The model calculates the spectral power density scattered and detected between 1 and 5 μm by a certain particle distribution and sensor configuration. From model calculations a modification based on the insertion of a compound ellipsoidal concentrator (CEC) has appeared as necessary. Its implementation has multiplied up to 100 the scattered optical power detected, significantly enhancing the detection limits of the sensor.

  2. Permissible Exposure Level for Lunar Dusts: Gaps are Closing

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  3. Exposure level and distribution characteristics of airborne bacteria and fungi in Seoul metropolitan subway stations.

    PubMed

    Kim, Ki Youn; Kim, Yoon Shin; Kim, Daekeun; Kim, Hyeon Tae

    2011-01-01

    The exposure level and distribution characteristics of airborne bacteria and fungi were assessed in the workers' activity areas (station office, bedroom, ticket office and driver's seat) and passengers' activity areas (station precinct, inside the passenger carriage, and platform) of the Seoul metropolitan subway. Among investigated areas, the levels of airborne bacteria and fungi in the workers' bedroom and station precincts were relatively high. No significant difference was found in the concentration of airborne bacteria and fungi between the underground and above ground activity areas of the subway. The genera identified in all subway activity areas with a 5% or greater detection rate were Staphylococcus, Micrococcus, Bacillus and Corynebacterium for airborne bacteria and Penicillium, Cladosporium, Chrysosporium, Aspergillus for airborne fungi. Staphylococcus and Micrococcus comprised over 50% of the total airborne bacteria and Penicillium and Cladosporium comprised over 60% of the total airborne fungi, thus these four genera are the predominant genera in the subway station. PMID:21173524

  4. Controlling the levels of airborne pollen: can heterogeneous photocatalysis help?

    PubMed

    Sapiña, M; Jimenez-Relinque, E; Castellote, M

    2013-10-15

    Airborne pollen is a worldwide problem because is a very important allergenic agent; it can be altered only by certain microorganisms and by some oxidizers, such as reactive oxygen species (ROS). On the other hand, heterogeneous photocatalysis (HPC) arose as a promising technology for reducing the level of contaminants in the air, based on their degradation by the production of ROS. In this paper, study of the feasibility of HPC to diminish the counts of pollen is undertaken. The research has been carried out at different levels, from solutions to mortar specimens with the evidence that HPC is able to reduce the amount of pollen grains. This is a major breakthrough that opens the door to a whole field of research, already full of gaps, whose implications could be quite controversial. PMID:24063577

  5. An evaluation of effect of airborne dust from a cotton mill on the guinea-pig ileum with reference to byssinosis.

    PubMed Central

    Cinkotai, F F; Franklin, D W

    1975-01-01

    The effect of airborne dust on the guinea-pig ileum was studied. Tyrode extracts of airborne dust collected freshly in the cardroom of a cotton mill, and extracts of air pollutant samples drawn on the roof of the mill and of the local town hall were all found to induce the guinea-pig ileum to contract when applied in a tissue-bath. However, the force of contraction with air pollutants was rather greater than that with the cardroom dust. Considering the variables involved, the ileum response to the cardroom dust may have been due to ordinary air pollutants which constitute a significant part of the dust. It is concluded that this pharmacological phenomenon is probably not relevant in the context of byssinosis. Images PMID:1156573

  6. Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery.

    PubMed

    Lewis, Ryan C; Gaffney, Shannon H; Le, Matthew H; Unice, Ken M; Paustenbach, Dennis J

    2012-09-01

    Workers handle catalysts extensively at petroleum refineries throughout the world each year; however, little information is available regarding the airborne concentrations and plausible exposures during this type of work. In this paper, we evaluated the airborne concentrations of 15 metals and total dust generated during solid catalyst loading and unloading operations at one of the largest petroleum refineries in the world using historical industrial hygiene samples collected between 1989 and 2006. The total dust and metals, which included aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, platinum, silicon, silver, vanadium, and zinc, were evaluated in relation to the handling of four different types of solid catalysts associated with three major types of catalytic processes. Consideration was given to the known components of the solid catalysts and any metals that were likely deposited onto them during use. A total of 180 analytical results were included in this analysis, representing 13 personal and 54 area samples. Of the long-term personal samples, airborne concentrations of metals ranged from <0.001 to 2.9mg/m(3), and, in all but one case, resulted in concentrations below the current U.S. Occupational Safety and Health Administration's Permissible Exposure Limits and the American Conference of Governmental Industrial Hygienists' Threshold Limit Values. The arithmetic mean total dust concentration resulting from long-term personal samples was 0.31mg/m(3). The data presented here are the most complete set of its kind in the open literature, and are useful for understanding the potential exposures during solid catalyst handling activities at this petroleum refinery and perhaps other modern refineries during the timeframe examined. PMID:22177528

  7. Assessing the performance of methods to detect and quantify African dust in airborne particulates.

    PubMed

    Viana, Mar; Salvador, Pedro; Artíñano, Begoña; Querol, Xavier; Alastuey, Andrés; Pey, Jorge; Latz, Achim J; Cabañas, Mercè; Moreno, Teresa; García dos Santos, Saúl; Herce, María Dolores; Diez Hernández, Pablo; Romero García, Dolores; Fernández-Patier, Rosalía

    2010-12-01

    African dust (AD) contributions to particulate matter (PM) levels may be reported by Member States to the European Commission during justification of exceedances of the daily limit value (DLV). However, the detection and subsequent quantification of the AD contribution to PM levels is complex, and only two measurement-based methods are available in the literature: the Spanish-Portuguese reference method (SPR), and the Tel Aviv University method (TAU). In the present study, both methods were assessed. The SPR method was more conservative in the detection of episodes (71 days identified as AD by SPR, vs 81 by TAU), as it is less affected by interferences with local dust sources. The mean annual contribution of AD was lower with the TAU method than with SPR (2.7 vs 3.5 ± 1.5 μg/m(3)). The SPR and TAU AD time series were correlated with daily aluminum levels (a known tracer of AD), as well as with an AD source identified by the Positive Matrix Factorization (PMF) receptor model. Higher r(2) values were obtained with the SPR method than with TAU in both cases (r(2) = 0.72 vs 0.56, y = 0.05x vs y = 0.06x with aluminum levels; r(2)=0.79 vs 0.43, y = 0.8x vs y = 0.4x with the PMF source). We conclude that the SPR method is more adequate from an EU policy perspective (justification of DLV exceedances) due to the fact that it is more conservative than the TAU method. Based on our results, the TAU method requires adaptation of the thresholds in the algorithm to refine detection of low-impact episodes and avoid misclassification of local events as AD. PMID:21049991

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

    PubMed

    Bigu, J; Grenier, M G

    1989-07-01

    An electrostatic precipitator based on charged water spray technology has been used in an underground uranium mine to control long-lived radioactive dust and short-lived aerosol concentration in a mine gallery where dust from a rock breaking/ore transportation operation was discharged. Two main sampling stations were established: one upstream of the dust precipitator and one downstream. In addition, dust samplers were placed at different locations between the dust discharge and the end of the mine gallery. Long-lived radioactive dust was measured using cascade impactors and nylon cyclone dust samplers, and measurement of the radioactivity on the samples was carried out by conventional methods. Radon and thoron progeny were estimated using standard techniques. Experiments were conducted under a variety of airflow conditions. A maximum radioactive dust reduction of about 40% (approximately 20% caused by gravitational settling) at a ventilation rate of 0.61 m3/sec was obtained as a result of the combined action of water scrubbing and electrostatic precipitation by the charged water spray electrostatic precipitator. This represents the optimum efficiency attained within the range of ventilation rates investigated. The dust reduction efficiency of the charged water spray decreased with increasing ventilation rate, i.e., decreasing air residence time, and hence, reduced dust cloud/charged water droplets mixing time. PMID:2756864

  9. Natural Airborne Dust and Heavy Metals: A Case Study for Kermanshah, Western Iran (2005–2011)

    PubMed Central

    PIRSAHEB, Meghdad; ZINATIZADEH, Aliakbar; KHOSRAVI, Touba; ATAFAR, Zahra; DEZFULINEZHAD, Saeed

    2014-01-01

    Abstract Background Dust pollution has become a serious environmental problem especially in recent decades. The present study aim was the investigation of the levels of PM10 concentration in Kermanshah, western Iran and also measured five important heavy metals (Pb, Cd, As, Hg and Cr) in some samples during 2005 to 2011. Methods A total 2277 samples were collected from air pollution measurement station belonging to the Department of Environment in Kermanshah. Furthermore, four samples were collected during dusty days to determine the selected heavy metals concentration. The samples were analyzed statistically using the SPSS Ver.16 Results The highest seasonal average concentration in spring was recorded in 2008 with 216.63μg/m3, and the maximum values of 267.79 and 249.09μg/m3 were observed in summer and winter in 2009, respectively. The maximum concentration of 127.1μg/m3 was in autumn in 2010. The metals concentration (Pb, Cd, As, Hg and Cr) of samples were 42.32±5.40, 37.45±9.29, 3.51±2.07, 1.88±1.64 and 0μg/g in July, 2009, respectively. Conclusion According to National Ambient Air Quality of USEPA guidelines, the most days with non-standard, warning, emergency and critical conditions were related to 2009 (120 days) while the least polluted days were recorded in 2006 (16 days). There are concerns about the increasing frequency and intensity trend of dust storms in recent years as a result of special condition in neighboring Western countries which it could endanger public health and environment. All measured heavy metals except mercury was higher than the standard level of WHO and USEPA. PMID:26005656

  10. 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.

  11. Airborne Interferometry using GNSS Reflections for Surface Level Estimation

    NASA Astrophysics Data System (ADS)

    Semmling, Maximilian; Beyerle, Georg; Schön, Steffen; Stosius, Ralf; Gerber, Thomas; Beckheinrich, Jamila; Markgraf, Markus; Ge, Maorong; Wickert, Jens

    2013-04-01

    The interferometric use of GNSS reflections for ocean altimetry can fill the gap in coverage of ocean observations. Today radar altimeters are used for large scale ocean observations to monitor e.g. global sea level change or circulation processes like El Niño. Spacial and temporal resolution of a single radar altimeter, however, is insufficient to observe mesoscale ocean phenomena like large oceanic eddies that are important indicators of climate change. The high coverage expected for a spaceborne altimeter based on GNSS reflections stimulated investigations on according interferometric methods. Several airborne experiments have been conducted using code observations. Carrier observations have a better precision but are severely affected by noise and have mostly been used in ground-based experiments. A new interferometric approach is presented using carrier observations for airborne application. Implementing a spectral retrieval noise reduction is achieved. A flight experiment was conducted with a Zeppelin airship on 2010/10/12 over Lake Constance at the border between Austria, Germany and Switzerland. The lake surface with an area of 536km2 is suitable for altimetric study as its decimeter range Geoid undulations are well-known. Three GNSS receiver were installed on the airship. A Javad Delta receiver recording direct signals for navigation. The DLR G-REX receiver recording reflected signals for scatterometry and the GORS (GNSS Occultation Reflectometry Scatterometry) receiver recording direct and reflected signals for interferometry. The airship's trajectory is determined from navigation data with a precision better than 10cm using regional augmentation. This presentation focuses on the interferometric analysis of GORS observations. Ray tracing calculations are used to model the difference of direct and reflected signals' path. Spectral retrieval is applied to determine Doppler residuals of modelled path difference and interferometric observations. Lake level

  12. Haul road dust control

    SciTech Connect

    Reed, W.R.; Organiscak, J.A.

    2007-10-15

    A field study was conducted to measure dust from haul trucks at a limestone quarry and a coal preparation plant waste hauling operation. The study found that primarily wind, distance and road treatment conditions notably affected the dust concentrations at locations next to, 50 ft from, and 100 ft away from the unpaved haulage road. Airborne dust measured along the unpaved haul road showed that high concentrations of fugitive dust can be generated with these concentrations rapidly decreasing to nearly background levels within 100 ft of the road. Instantaneous respirable dust measurements illustrated that the trucks generate a real-time dust cloud that has a peak concentration with a time-related decay rate as the dust moves past the sampling locations. The respirable dust concentrations and peak levels were notably diminished as the dust cloud was transported, diluted, and diffused by the wind over the 100 ft distance from the road. Individual truck concentrations and peak levels measured next to the dry road surface test section were quite variable and dependent on wind conditions, particularly wind direction, with respect to reaching the sampling location. The vast majority of the fugitive airborne dust generated from unpaved and untreated haulage roads was non-respirable. 6 figs.

  13. Airborne Fungi in Sahara Dust Aerosols Reaching the Eastern Caribbean: II. Species Identification Using Molecular Techniques

    NASA Astrophysics Data System (ADS)

    de La Mota, A.; Betancourt, C.; Detres, Y.; Armstrong, R.

    2003-12-01

    Fungi samples from filters collected in Castle Bruce, Dominica from March through July 2002, were previously purified and identified to genus level using classic macroscopic and microscopic techniques. A total of 105 isolated colonies were cultured in liquid media and the mycelial mats used for DNA extraction. PCR was used to amplify the ITS region of the rDNA using the ITS1 and ITS4 primers. Both strands of the amplified products were sequenced and the final identification to species level was completed by a GenBank search. Fourteen different species and one fungal endophyte were identified from genders Aspergillus,Penicillium, Fusarium, Cladosporium, Curvularia and Phanerochaete. Some of these species such as A. fumigatus, A. japonicus, P. citrinum and C. cladosporoides are known to cause respiratory disorders in humans. A. fumigatus causes an aggressive pulmonary allergic response that might result in allergic bronchopulmonary aspergillosis. Other species such as F. equiseti and C. brachyspora are plant pathogens affecting economically important crops. Sahara dust is an important source of fungal spores of species that are not common in the Caribbean region.

  14. The Martian polar CAP - Radiative effects of ozone, clouds, and airborne dust

    NASA Astrophysics Data System (ADS)

    Lindner, B. L.

    1990-02-01

    The solar and thermal flux striking the polar cap of Mars is computed for various ozone, dust, and cloud abundances and for three solar zenith angles. Ozone does not significantly affect the total energy budget of the polar cap. Hence the observed hemispherical asymmetry in ozone abundance causes only an insignificant hemispherical asymmetry in the polar caps. Vertical optical depths of dust and cloud ranging from zero to 1 cause little change in the total flux absorbed by the polar cap near its edge but increase the absorbed flux significantly as one travels poleward. Hemispherical asymmetries in dust abundance, cloud cover, and surface pressure combine to cause a significant hemispherical asymmetry in the total flux absorbed by the residual polar caps, which helps to explain the dichotomy in the residual polar caps on Mars. Other processes which affect the energy budget of the polar cap are proposed and reviewed, particularly with respect to their interaction with the radiative effects of clouds and dust.

  15. Influence of negative pressurization on airborne microbial and radon levels

    SciTech Connect

    Kalliokoski, P.; Korhonen, P.; Kokotti, H.; Pasanen, A.L.; Rautiala, S.; Rantamaeki, J.

    1999-07-01

    The negative pressure inside a building is the main driving force for the entry of both radon and fungal spores. This study was conducted to test the suitability of depressurization to facilitate simultaneously the detection of fungal growth within the lower parts of building envelope and the risk of radon entry. Pressure difference was increased in three steps to 24--28 Pa in two wooden buildings known to suffer from long-term water damages. At the end, pulses of negative pressure were generated. Airborne viable fungal counts, radon and particle counts were followed during the tests together with the ventilation rate and particle count. The absolute concentrations of the impurities studied did not increase significantly or even decreased during the tests due to enhanced ventilation. However, when the increase in the ventilation rate was taken into consideration it was found that the entry rate of all the contaminants increased. The changes were larger in the tighter building where the radon entry rate increased systematically with the pressure difference reaching finally 13.8-fold level compared to the initial value. In the less tight building, the corresponding highest radon entry rate ratio was 9.5. Very large increases, up to 42-fold, were observed in the viable spore count ratio in the tighter building during the tests. In the leaky building, the changes were again considerably smaller; the maximum ratio was 4.2. Increases in particle emissions were smaller than those observed in fungal counts. The pulses were less effective than continuous depressurization. The results show that negative pressurization can be used to increase the release of fungal spores in order to detect hidden fungal growth. This kind of test is especially effective if there are no major leaks in the clean part of the building envelope. The method allows simultaneous rapid checking of need for radon mitigation.

  16. MODIS technical report series. Volume 3: MODIS airborne simulator level 1B data user's guide

    NASA Technical Reports Server (NTRS)

    Gumley, Liam E.; Hubanks, Paul A.; Masuoka, Edward J.

    1994-01-01

    The purpose of this document is to describe the characteristics of moderate resolution imaging spectroradiometer (MODIS) airborne simulator level 1B data, the calibration and geolocation methods used in processing, the structure and format of the level 1B data files, and methods for accessing the data. The MODIS airborne simulator is a scanning spectrometer which flies on a NASA ER-2 and provides spectral information similar to that which will be provided by the MODIS.

  17. Species-specific Fungal DNA in Airborne Dust as Surrogate for Occupational Mycotoxin Exposure?

    PubMed Central

    Halstensen, Anne Straumfors

    2008-01-01

    Possible health risks associated with occupational inhalation of mycotoxin-containing dust remain largely unknown, partly because methods for mycotoxin detection are not sensitive enough for the small dust masses obtained by personal sampling, which is needed for inhalable exposure measurements. Specific and sensitive PCR detection of fungi with mycotoxin-producing potential seem to be a good surrogate for occupational exposure measurements that include all fungal structures independent of morphology and cultivability. Results should, however, be interpreted with caution due to variable correlations with mycotoxin concentrations. PMID:19330091

  18. Thymus-directed immunotoxicity of airborne dust particles from Upper Silesia (Poland) under acute extrapulmonary studies in mice

    SciTech Connect

    Kozlowska, E.; Krzystniak, K.; Drela, N.

    1996-12-27

    Industrial air pollutants from Upper Silesia, Poland, contain over 250 polycyclic and heterocyclic aromatic hydrocarbons and heavy metals, including mutagenic and carcinogenic chemicals that have been shown to from DNA adducts. Over 4 million habitants of Silesia are permanently exposed to the industrial pollution by pulmonary and dermal routes and by contaminated food and water. These chemicals, when examined separately in animals models, were proven immunotoxic. We studied the extrapulmonary immunotoxic potential of a typical mixture of Silesian filter-suspended matter from a selected area, over a specific season and time period. Early changes in the immune system were analyzed in BALB/c mice exposed ip to acute doses of 20-330 mg dust mixture/kg body weight (0.06-1.0 LD50). No major changes were noted for weight and the cellularity of spleen, liver and kidneys. However, dramatic decrease in thymus weight index and thymocyte cell count were noted as early as 24-72 h postexposure, which correlated with almost complete depletion of immature, double-positive CD4{sup +}CD8{sup +} thymocytes. Changes in spleen were less profound; however, increased depletion of B cells over T cells was noted at high doses of the suspended matter. Exposure to the airborne dust also decreased cytokine production by spleen cells, such as interferon-{gamma} (IFN-{gamma}) and tumor necrosis factor-{alpha} (TNF-{alpha}). Overall, a single exposure to Silesian dust, even at the relatively low 0.06 LD50 dose, affected lymphokine production, suppressed B-cell proliferative response, and depleted thymuses of immature, double-positive CD4{sup +}CD8{sup +} cells. A chemical synergism is suspected. To our knowledge, none of the known components of Silesian suspended matter, when examined as a single chemical, was shown to exert such a profound biological effect. 32 refs., 5 figs.

  19. Northern Idaho house dust and soil lead levels compared to the Bunker Hill Superfund Site.

    PubMed

    Spalinger, Susan M; von Braun, Margrit C; Petrosyan, Varduhi; von Lindern, Ian H

    2007-07-01

    House dust has been identified as a major exposure medium for lead (Pb) in children. High levels of Pb in soil and house dust have been recorded at the Bunker Hill Superfund Site (BHSS) in northern Idaho, an historic mining and smelting district. Soil and dust remediation at the site was required; however, regional background soil and dust Pb levels had not been well characterized. The objective of this survey was to determine background house dust Pb levels and to compare those levels with concentrations, and dust and Pb loading rates measured at the BHSS. Soil and house dust samples were collected in five towns demographically similar to the BHSS but unaffected by the mining industry. The background concentrations and loading rates were significantly lower than those observed at the site. House age was a significant factor affecting background soil and house dust Pb concentrations and loading rates. PMID:17171279

  20. Environmental releases from fuel cycle facility: part 1: radionuclide resuspension vs. stack releases on ambient airborne uranium and thorium levels.

    PubMed

    Masson, Olivier; Pourcelot, Laurent; Boulet, Béatrice; Cagnat, Xavier; Videau, Gérard

    2015-03-01

    Airborne activity levels of uranium and thorium series were measured in the vicinity (1.1 km) of a uranium (UF4) processing plant, located in Malvési, south of France. Regarding its impact on the environment, this facility is characterized by its routine atmospheric releases of uranium and by the emission of radionuclide-labelled particles from a storage pond filled with waste water or that contain dried sludge characterized by traces of plutonium and thorium ((230)Th). This study was performed during a whole year (November 2009-November 2010) and based on weekly aerosol sampling. Thanks to ICP-MS results, it was possible to perform investigations of uranium and thorium decay product concentration in the air. The number of aerosol filters sampled (50) was sufficient to establish a relationship between airborne radionuclide variations and the wind conditions. As expected, the more the time spent in the plume, the higher the ambient levels. The respective contributions of atmospheric releases and resuspension from local soil and waste ponds on ambient dust load and uranium-bearing aerosols were estimated. Two shutdown periods dedicated to facility servicing made it possible to estimate the resuspension contribution and to specify its origin (local or regional) according to the wind direction and remote background concentration. Airborne uranium mainly comes from the emission stack and, to a minor extent (∼20%), from wind resuspension of soil particles from the surrounding fields and areas devoted to waste storage. Moreover, weighed activity levels were clearly higher during operational periods than for shutdown periods. PMID:25613358

  1. Assessment of the Levels of Airborne Bacteria, Gram-Negative Bacteria, and Fungi in Hospital Lobbies

    PubMed Central

    Park, Dong-Uk; Yeom, Jeong-Kwan; Lee, Won Jae; Lee, Kyeong-Min

    2013-01-01

    Aims: We assessed the levels of airborne bacteria, Gram-negative bacteria (GNB), and fungi in six hospital lobbies, and investigated the environmental and hospital characteristics that affected the airborne microorganism levels. Methods: An Andersen single-stage sampler equipped with appropriate nutrition plate agar was used to collect the samples. The three types of microorganisms were repeatedly collected at a fixed location in each hospital (assumed to be representative of the entire hospital lobby) from 08:00 through 24:00, with a sampling time of less than 5 min. Temperature and relative humidity were simultaneously monitored. Results: Multiple regression analysis was used to identify the major factors affecting microorganism levels. The average levels of bacteria (7.2 × 102 CFU/m3), GNB (1.7 × 10 CFU/m3), and fungi (7.7 × 10 CFU/m3) indicated that all hospital lobbies were generally contaminated. Season was the only factor that significantly affected the levels of all microorganisms (p < 0.0001), where contamination was the highest during the summer, significantly higher than during the winter. Other significant factors varied by microorganism, as follows: airborne bacteria (number of people in the lobby, sampling time), GNB (scale of hospital), and fungi (humidity and air temperature). Conclusions: Hospital lobby air was generally contaminated with microorganisms, including bacteria, GNB, and fungi. Environmental factors that may significantly influence the airborne concentrations of these agents should be managed to minimize airborne levels. PMID:23435586

  2. Improving the modeling of road dust levels for Barcelona at urban scale and street level

    NASA Astrophysics Data System (ADS)

    Amato, Fulvio; Zandveld, Peter; Keuken, Menno; Jonkers, Sander; Querol, Xavier; Reche, Cristina; Denier van der Gon, Hugo A. C.; Schaap, Martijn

    2016-01-01

    Road dust emission is an emerging issue in air quality due to the lack of remediation measures in contrast to vehicle exhaust emissions. The evidence of receptor modeling studies allows for quantifying impact on a few receptors, but the high cost of PM chemical speciation data and the questionable representativeness of single monitoring sites, limit considerably the development of population exposure estimates and epidemiologic studies based on georeferenced data. This study attempts to initiate and promote urban-scale dispersion modeling for road dust emissions, which will allow for a more robust estimate of population exposure and health outcomes. The TNO URBIS (URBan Information System) model was applied in the city of Barcelona, implementing a Gaussian line source and a street canyon dispersion model, together with new experimental estimates of road dust emission factors and algorithm to describe the time variability. Annual, daily and hourly road dust contributions were simulated and validated against observation of PM10, mineral dust and hourly PM2.5-10 concentrations. Results show that road dust contributed 9-15% to PM10 levels at background sites, and 23-44% at traffic sites. Highest contributions were modeled in the commercial/residential district where most of population live and work (Eixample) structured by 120 m wide square blocks, separated by roads with >10,000 vehicles per day. Street level contributions rise up to 20 μg/m3 (96% of roads) and an additional 3% of roads within 20-40 μg/m3. Hourly simulations of road dust contributions revealed to benefit from the implementation of the new emission module (Amato et al., 2012), able to describe the exponential recovery of road dust emission potential after rain events, when compared to common approach such as the use of constant emission factor or an ON/OFF approach. Correlation coefficients with observed data varied from 0.61, 0.58 and 0.43 for annual, daily and hourly means, respectively, revealing

  3. Transport of mineral dust derived from airborne wind lidar measurements during SALTRACE

    NASA Astrophysics Data System (ADS)

    Chouza, Fernando; Reitebuch, Oliver; Groß, Silke; Rahm, Stephan; Freudenthaler, Volker; Toledano, Carlos; Weinzierl, Bernadett

    2015-04-01

    During the SALTRACE field experiment conducted between the 10 of June and the 15 of July 2013, the transport and properties of Saharan dust were characterized by a 2-µm Doppler wind lidar (DWL) deployed on the DLR Falcon 20 research aircraft. Unlike aerosol lidars, the DLW is able to simultaneously measure wind fields and -by means of an adequate calibration- aerosol optical properties, which is more adequate for aerosol transport studies. The retrieved horizontal and vertical wind speed provide a direct observation of dust long range transport mechanisms across the Atlantic (e.g. by the African easterly jet) from Western Africa to the Caribbean. Vertical wind observations revealed the structure of island induced lee waves in the Cape Verde and Barbados regions. A novel method for the calibration of DWLs based on simultaneous measurements with a ground-based aerosol lidar and sun photometer was developed. After being calibrated, the system is able to retrieve quantitative aerosol backscatter and extinction coefficients, which is usually not obtained from coherent lidars. Results from the validation with a ground-based aerosol lidar in Barbados and the CALIPSO satellite instrument will be discussed.

  4. The Martian Dust Cycle: Observations and Modeling

    NASA Technical Reports Server (NTRS)

    Kahre, Melinda A.

    2013-01-01

    The dust cycle is critically important for Mars' current climate system. Suspended atmospheric dust affects the radiative balance of the atmosphere, and thus greatly influences the thermal and dynamical state of the atmosphere. Evidence for the presence of dust in the Martian atmosphere can be traced back to yellow clouds telescopically observed as early as the early 19th century. The Mariner 9 orbiter arrived at Mars in November of 1971 to find a planet completely enshrouded in airborne dust. Since that time, the exchange of dust between the planet's surface and atmosphere and the role of airborne dust on Mars' weather and climate has been studied using observations and numerical models. The goal of this talk is to give an overview of the observations and to discuss the successes and challenges associated with modeling the dust cycle. Dust raising events on Mars range in size from meters to hundreds of kilometers. During some years, regional storms merge to produce hemispheric or planet encircling dust clouds that obscure the surface and raise atmospheric temperatures by tens of kelvin. The interannual variability of planet encircling dust storms is poorly understood. Although the occurrence and season of large regional and global dust storms are highly variable from one year to the next, there are many features of the dust cycle that occur year after year. A low-level dust haze is maintained during northern spring and summer, while elevated levels of atmospheric dust occur during northern autumn and winter. During years without global-scale dust storms, two peaks in total dust loading are generally observed: one peak occurs before northern winter solstice and one peak occurs after northern winter solstice. Numerical modeling studies attempting to interactively simulate the Martian dust cycle with general circulation models (GCMs) include the lifting, transport, and sedimentation of radiatively active dust. Two dust lifting processes are commonly represented in

  5. Saharan dust levels in Greece and received inhalation doses

    NASA Astrophysics Data System (ADS)

    Mitsakou, C.; Kallos, G.; Papantoniou, N.; Spyrou, C.; Solomos, S.; Astitha, M.; Housiadas, C.

    2008-06-01

    The desert of Sahara is one of the major sources of mineral dust on Earth, producing around 2×108 tons/yr. Under certain weather conditions, dust particles from Saharan desert get transported over the Mediterranean Sea and most of Europe. The limiting values set by the directive EC/30/1999 of European Union can easily be exceeded by the transport of desert dust particles in all south European areas and especially urban. In this study, the effects of dust transport on air quality in several Greek urban areas are quantified. PM10 concentration values from stationary monitoring stations are compared to dust concentrations for the 4-year period 2003-2006. The dust concentration values in the Greek areas were estimated by the SKIRON modelling system coupled with embedded algorithms describing the dust cycle. The mean annual dust contribution to daily-averaged PM10 concentration values was found to be around or even greater than 10% in the urban areas throughout the years examined. Natural dust transport may contribute by much more than 20% to the annual number of exceedances - PM10 values greater than EU limits - depending on the specific monitoring location. In a second stage of the study, the inhaled lung dose received by the residents in various Greek locations is calculated. The particle deposition efficiency of mineral dust at the different parts of the human respiratory tract is determined by applying a lung dosimetry numerical model, which incorporates inhalation dynamics and aerosol physical processes. The inhalation dose from mineral dust particles was greater in the upper respiratory system (extrathoracic region) and less significant in the lungs, especially in the sensitive alveolar region. However, in cases of dust episodes, the amounts of mineral dust deposited along the human lung are comparable to those received during exposure in heavily polluted urban or smoking areas.

  6. Saharan dust levels in Greece and received inhalation doses

    NASA Astrophysics Data System (ADS)

    Mitsakou, C.; Kallos, G.; Papantoniou, N.; Spyrou, C.; Solomos, S.; Astitha, M.; Housiadas, C.

    2008-12-01

    The desert of Sahara is one of the major sources of mineral dust on Earth, producing around 2×108 tons/yr. Under certain weather conditions, dust particles from Saharan desert get transported over the Mediterranean Sea and most of Europe. The limiting values set by the directive EC/30/1999 of European Union can easily be exceeded by the transport of desert dust particles in the south European Region and especially in urban areas, where there is also significant contribution from anthropogenic sources. In this study, the effects of dust transport on air quality in several Greek urban areas are quantified. PM10 concentration values from stationary monitoring stations are compared to dust concentrations for the 4-year period 2003-2006. The dust concentration values in the Greek areas were estimated by the SKIRON modelling system coupled with embedded algorithms describing the dust cycle. The mean annual dust contribution to daily-averaged PM10 concentration values was found to be around or even greater than 10% in the urban areas throughout the years examined. Natural dust transport may contribute by more than 20% to the annual number of exceedances - PM10 values greater than EU limits - depending on the specific monitoring location. In a second stage of the study, the inhaled lung dose received by the residents in various Greek locations is calculated. The particle deposition efficiency of mineral dust at the different parts of the human respiratory tract is determined by applying a lung dosimetry numerical model, which incorporates inhalation dynamics and aerosol physical processes. The inhalation dose from mineral dust particles was greater in the upper respiratory system (extrathoracic region) and less significant in the lungs, especially in the sensitive alveolar region. However, in cases of dust episodes, the amounts of mineral dust deposited along the human lung are comparable to those received during exposure in heavily polluted urban or smoking areas.

  7. Chemical speciation, human health risk assessment and pollution level of selected heavy metals in urban street dust of Shiraz, Iran

    NASA Astrophysics Data System (ADS)

    Keshavarzi, Behnam; Tazarvi, Zahra; Rajabzadeh, Mohammad Ali; Najmeddin, Ali

    2015-10-01

    The distribution, pollution level, sources and health risk of Hg, As, Cd, Cu, Cr, Ni, Mn, Fe, Pb, Sb and Zn in urban street dust were investigated. X-ray diffraction analysis of dust samples shows that the mineralogy of airborne dusts is dominated by calcite, dolomite and quartz. The total concentration of trace elements across the sampling sites ranged from 36.8 to 234.3 mg kg-1 for Pb, 0.004-4.504 mg kg-1 for Hg, 160.9-778.3 mg kg-1 for Zn, 245-652 mg kg-1 for Mn, 39.4-117.9 mg kg-1 for Ni, 31.6-105.9 mg kg-1 for Cr, 49.8-232.5 mg kg-1 for Cu, 5.3-8.6 mg kg-1 for As, 0.31-0.85 mg kg-1 for Cd, 0.76-9.45 mg kg-1 for Sb, and 16,300-24,900 mg kg-1 for Fe. The enrichment factor results reveal the following order: Cu > Hg > Sb > Zn > Pb > Ni > Cr > As > Mn > Cd > Fe. Among the measured elements, the highest mobility factor belongs to Pb (79.2%), Hg (74.6%), Zn (64.1%) and Mn (56.4%). According to the calculated Hazard Quotient (HQ) and Hazard Index (HI), special attention should be paid to Hg, Pb, Zn, and Mn in the street dusts of Shiraz. Multivariate statistics indicate that traffic, natural soil particles and industrial activities are likely to be the main sources of heavy metals in Shiraz street dusts.

  8. Imaging-based dust sensors: equipment and methods

    NASA Astrophysics Data System (ADS)

    Bonifazi, Giuseppe; Greco, Sonia

    2004-05-01

    Dust detection and control in real time, represent one of the most challenging problem in all those environments where fine and ultrafine airborne particulate solids products are present. The presence of such products can be linked to several factors, often directly related and influenced by the working-production actions performed. Independently from the causes generating dust, airborne contaminants are an occupational problem of increasing interest as they are related to a wide number of diseases. In particular, airborne dusts are well known to be associated with several classical occupational lung diseases, such as the pneumoconiosis, especially at high levels of exposure. Nowadays there is also an increasing interest in other dust related diseases, from the most serious as cancer and asthma, to those related with allergies or irritation and other illnesses, also occurring at lower levels of exposure. Among the different critical factors influencing health risk for airborne dust exposure, mainly four have to be considered, that is: i) nature of the dust resulting from working in terms of presence of specific poisoning material, i.e. free silica, and morphological and morphometrical attributes of particulates constituting airborne dust; ii) size of the particles, iii) duration of exposure time and, finally, iv) airborne dust concentration in the breathing zone where the worker performs his activity. A correct dust detection is not easy, especially if some of the previous mentioned factors, have to be detected and quantified in real time in order to define specific "on-line" control actions aimed to reduce the level of the exposure to dust of the workers, as for example: i) modification of aspirating devices operating condition, change of filtering cleaning sequence, etc. . The more severe are the environmental conditions, in terms of dust presence (in quantity and quality) more difficult is to utilize efficient sampling devices. Detection devices, in fact, tend

  9. Assessment of the permissible exposure level to manganese in workers exposed to manganese dioxide dust.

    PubMed Central

    Roels, H A; Ghyselen, P; Buchet, J P; Ceulemans, E; Lauwerys, R R

    1992-01-01

    The prevalence of neuropsychological and respiratory symptoms, lung ventilatory parameters, neurofunctional performances (visual reaction time, eye-hand coordination, hand steadiness, audioverbal short term memory), and several biological parameters (calcium, iron, luteinising hormone (LH), follicle stimulating hormone (FSH), and prolactin concentrations in serum, blood counts, manganese (Mn) concentration in blood and in urine) were examined in a group of workers (n = 92) exposed to MnO2 dust in a dry alkaline battery factory and a matched control group (n = 101). In the battery plant, the current exposure of the workers to airborne Mn was measured with personal samplers and amounted on average (geometric mean) to 215 and 948 micrograms Mn/m3 for respirable and total dust respectively. For each worker, the lifetime integrated exposure to respirable and total airborne Mn dust was also assessed. The geometric means of the Mn concentrations in blood (MnB) and in urine (MnU) were significantly higher in the Mn exposed group than in the control group (MnB 0.81 v 0.68 microgram/100 ml; MnU 0.84 v 0.09 microgram/g creatinine). On an individual basis, MnU and MnB were not related to various external exposure parameters (duration of exposure, current exposure, or lifetime integrated exposure to airborne Mn). On a group basis, a statistically significant association was found between MnU and current Mn concentrations in air. No appreciable difference between the exposed and the control workers was found with regard to the other biological measurements (calcium, LH, FSH, and prolactin in serum). Although the erythropoietic parameters and serum iron concentration were in the normal range for both groups, there was a statistically significant trend towards lower values in the Mn exposed workers. The prevalences of reported neuropsychological and respiratory symptoms, the lung function parameters, and the audioverbal short term memory scores did not differ between the control

  10. An Improved Platform Levelling System for Airborne Gravity Meters.

    NASA Astrophysics Data System (ADS)

    Brady, N.

    2014-12-01

    Recent advances in sensor technology have enabled Lacoste and Romberg type relative gravity meters to improve in accuracy to the point where other non-sensor related sources of error serve to limit the overall accuracy of the system. One of these sources of error is derived from the inability of the platform, in which the sensor is mounted, to keep the sensor perfectly level during survey flight. Off level errors occur when the aircraft is unable to maintain straight and level flight along a survey line. The levelling platform of a typical Lacoste and Romberg type dynamic gravity meter utilizes a complex feedback loop involving both accelerometers and gyroscopes with an output connected to torque motors mounted to the platform to sense an off level situation and correct for it. The current system is limited by an inability of the platform to distinguish between an acceleration of the platform due to a change in heading, altitude or speed of the aircraft and a true change in the local gravity vertical. Both of these situations cause the platform to tilt in reponse however the aircraft acceleration creates an error in the gravity measurement. These off level errors can be corrected for to a limited degree depending on the algorithm used and the size and duration of the causal acceleration. High precision GPS now provides accurate real time position information which can be used to determine if an accleration is a real level change or due to an anomalous acceleration. The correct implementation of the GPS position can significantly improve the accuracy of the platform levelling including keeping the platform level during course reversals or drape flying during a survey. This can typically improve the quality of the gravity data before any processing corrections. The enhanced platform also reduces the time taken to stabilize the platform at the beginning of a survey line therefore improving the efficiency of the data collection. This paper discusses the method and

  11. Estimate of safe human exposure levels for lunar dust based on comparative benchmark dose modeling.

    PubMed

    James, John T; Lam, Chiu-Wing; Santana, Patricia A; Scully, Robert R

    2013-04-01

    Brief exposures of Apollo astronauts to lunar dust occasionally elicited upper respiratory irritation; however, no limits were ever set for prolonged exposure to lunar dust. The United States and other space faring nations intend to return to the moon for extensive exploration within a few decades. In the meantime, habitats for that exploration, whether mobile or fixed, must be designed to limit human exposure to lunar dust to safe levels. Herein we estimate safe exposure limits for lunar dust collected during the Apollo 14 mission. We instilled three respirable-sized (∼2 μ mass median diameter) lunar dusts (two ground and one unground) and two standard dusts of widely different toxicities (quartz and TiO₂) into the respiratory system of rats. Rats in groups of six were given 0, 1, 2.5 or 7.5 mg of the test dust in a saline-Survanta® vehicle, and biochemical and cellular biomarkers of toxicity in lung lavage fluid were assayed 1 week and one month after instillation. By comparing the dose--response curves of sensitive biomarkers, we estimated safe exposure levels for astronauts and concluded that unground lunar dust and dust ground by two different methods were not toxicologically distinguishable. The safe exposure estimates were 1.3 ± 0.4 mg/m³ (jet-milled dust), 1.0 ± 0.5 mg/m³ (ball-milled dust) and 0.9 ± 0.3 mg/m³ (unground, natural dust). We estimate that 0.5-1 mg/m³ of lunar dust is safe for periodic human exposures during long stays in habitats on the lunar surface. PMID:23614726

  12. Analysis of Measurements of Saharan Dust by Airborne and Ground-based Remote Sensing Methods during the Puerto Rico Dust Experiment (PRIDE)

    NASA Technical Reports Server (NTRS)

    Reid, Jeffrey S.; Kinney, James E.; Westphal, Douglas L.; Holben, Brent N.; Welton, E. Judd; Tsay, Si-Chee; Eleuterio, Daniel P.; Campbell, James; Christopher, Sundar A.; Jonsson, Haflidi H.

    2003-01-01

    For 26 days in mid-June and July 2000, a research group comprised of U.S. Navy, NASA, and university scientists conducted the Puerto Rico Dust Experiment (PRIDE). In this paper we give a brief overview of mean meteorological conditions during the study. We focus on findings on African dust transported into the Caribbean utilizing Navajo aircraft and AERONET Sun photometer data. During the study midvisible aerosol optical thickness (AOT) in Puerto Rico averaged 0.25, with a maximum less than 0.5 and with clean marine periods of _0.08. Dust AOTs near the coast of Africa (Cape Verde Islands and Dakar) averaged _0.4, 30% less than previous years. By analyzing dust vertical profiles in addition to supplemental meteorology and MPLNET lidar data we found that dust transport cannot be easily categorized into any particular conceptual model. Toward the end of the study period, the vertical distribution of dust was similar to the commonly assumed Saharan Air Layer (SAL) transport. During the early periods of the study, dust had the highest concentrations in the marine and convective boundary layers with only a, weak dust layer in the SAL being present, a state usually associated with wintertime transport patterns. We corroborate the findings of Maring et al. that in most cases, there was an unexpected lack of vertical stratification of dust particle size. We systematically analyze processes which may impact dust vertical distribution and determine and speculate that dust vertical distribution predominately influenced by flow patterns over Africa and differential advection couple with mixing by easterly waves and regional subsidence.

  13. Analysis of measurements of Saharan dust by airborne and ground-based remote sensing methods during the Puerto Rico Dust Experiment (PRIDE)

    NASA Astrophysics Data System (ADS)

    Reid, Jeffrey S.; Kinney, James E.; Westphal, Douglas L.; Holben, Brent N.; Welton, Ellsworth J.; Tsay, Si-Chee; Eleuterio, Daniel P.; Campbell, James R.; Christopher, Sundar A.; Colarco, P. R.; Jonsson, Haflidi H.; Livingston, John M.; Maring, Hal B.; Meier, Michael L.; Pilewskie, Peter; Prospero, Joseph M.; Reid, Elizabeth A.; Remer, Lorraine A.; Russell, Philip B.; Savoie, Dennis L.; Smirnov, Alexander; Tanré, Didier

    2003-10-01

    For 26 days in mid-June and July 2000, a research group comprised of U.S. Navy, NASA, and university scientists conducted the Puerto Rico Dust Experiment (PRIDE). In this paper we give a brief overview of mean meteorological conditions during the study. We focus on our findings on African dust transported into the Caribbean utilizing a Navajo aircraft and AERONET Sun photometer data. During the study midvisible aerosol optical thickness (AOT) in Puerto Rico averaged 0.25, with a maximum >0.5 and with clean marine periods of ˜0.08. Dust AOTs near the coast of Africa (Cape Verde Islands and Dakar) averaged ˜0.4, 30% less than previous years. By analyzing dust vertical profiles in addition to supplemental meteorology and MPLNET lidar data we found that dust transport cannot be easily categorized into any particular conceptual model. Toward the end of the study period, the vertical distribution of dust was similar to the commonly assumed Saharan Air Layer (SAL) transport. During the early periods of the study, dust had the highest concentrations in the marine and convective boundary layers with only a weak dust layer in the SAL being present, a state usually associated with wintertime transport patterns. We corroborate the findings of [2003] that in most cases, there was an unexpected lack of vertical stratification of dust particle size. We systematically analyze processes that may impact dust vertical distribution and speculate that dust vertical distribution predominately influenced by flow patterns over Africa and differential advection coupled with fair weather cloud entrainment, mixing by easterly waves, and regional subsidence.

  14. Lung cancer in relation to airborne radiation levels

    SciTech Connect

    Helsing, K.J.; Natta, P.V.; Comstock, G.W. ); Kalin, Heidi ) Chee, E. )

    1992-01-01

    A 1986 aeroradiometric survey of the eastern two-thirds of Washington County, Maryland provided and opportunity to study lung cancers in relation to gamma radiation levels. In the first approach, lung cancer deaths between 1963 and 1975 in four areas of the county categorized as low, moderately low, moderately high, and high showed relative risks of 1.00, 0.93, 1.01, and 1.43, respectively, after adjustment of sex, age, and smoking. A second approach used lung cancer cases diagnosed between 1975 and 1989, controls matched to cases by race, sex, and age, and aerometric radiation readings above the individual residences. In four levels of increasing gamma radiation, odds ratios adjusted for smoking were 1.00, 0.84, 0.90, and 0.92, respectively. No differences were statistically significant.

  15. Exposure of bakery and pastry apprentices to airborne flour dust using PM2.5 and PM10 personal samplers

    PubMed Central

    Mounier-Geyssant, Estelle; Barthélemy, Jean-François; Mouchot, Lory; Paris, Christophe; Zmirou-Navier, Denis

    2007-01-01

    Background This study describes exposure levels of bakery and pastry apprentices to flour dust, a known risk factor of occupational asthma. Methods Questionnaires on work activity were completed by 286 students. Among them, 34 performed a series of two personal exposure measurements using a PM2.5 and PM10 personal sampler during a complete work shift, one during a cold ("winter") period, and the other during a hot ("summer") period. Results Bakery apprentices experience greater average PM2.5 and PM10 exposures than pastry apprentices (p < 0.006). Exposure values for both particulate fractions are greater in winter (average PM10 values among bakers = 1.10 mg.m-3 [standard deviation: 0.83]) than in summer (0.63 mg.m-3 [0.36]). While complying with current European occupational limit values, these exposures exceed the ACGIH recommendations set to prevent sensitization to flour dust (0.5 mg.m-3). Over half the facilities had no ventilation system. Conclusion Young bakery apprentices incur substantial exposure to known airways allergens, a situation that might elicit early induction of airways inflammation. PMID:17976230

  16. Predicting Airborne Particle Levels Aboard Washington State School Buses

    PubMed Central

    Adar, Sara D.; Davey, Mark; Sullivan, James R.; Compher, Michael; Szpiro, Adam; Liu, L.-J. Sally

    2008-01-01

    School buses contribute substantially to childhood air pollution exposures yet they are rarely quantified in epidemiology studies. This paper characterizes fine particulate matter (PM2.5) aboard school buses as part of a larger study examining the respiratory health impacts of emission-reducing retrofits. To assess onboard concentrations, continuous PM2.5 data were collected during 85 trips aboard 43 school buses during normal driving routines, and aboard hybrid lead vehicles traveling in front of the monitored buses during 46 trips. Ordinary and partial least square regression models for PM2.5 onboard buses were created with and without control for roadway concentrations, which were also modeled. Predictors examined included ambient PM2.5 levels, ambient weather, and bus and route characteristics. Concentrations aboard school buses (21 μg/m3) were four and two-times higher than ambient and roadway levels, respectively. Differences in PM2.5 levels between the buses and lead vehicles indicated an average of 7 μg/m3 originating from the bus's own emission sources. While roadway concentrations were dominated by ambient PM2.5, bus concentrations were influenced by bus age, diesel oxidative catalysts, and roadway concentrations. Cross validation confirmed the roadway models but the bus models were less robust. These results confirm that children are exposed to air pollution from the bus and other roadway traffic while riding school buses. In-cabin air pollution is higher than roadway concentrations and is likely influenced by bus characteristics. PMID:18985175

  17. A survey of metal levels in street dusts in an inner London neighborhood

    SciTech Connect

    Leharne, S.; Charlesworth, D.; Chowdhry, B. )

    1992-01-01

    Dust samples were collected from various roads situated in the Globetown Neighborhood area of East London. The samples were analyzed for lead, copper, nickel, manganese, iron, and aluminum by flame atomic absorption spectroscopy. The results indicate that lead levels in roads designated as busy are significantly greater than residential roads. The highest lead levels, though, were found in the vicinity of a car repair workshop. Iron levels in the vicinity of scrap metal yards are significantly higher than levels in residential roads. Aluminum levels, a putative indicator of crustal contributions to dust metal burdens, are significantly greater in residential roads and in the vicinity of scrap metal yards compared to busy roads. Manganese nickel, and copper in dust levels are evenly dispersed throughout the area. Finally, the results indicate that possible hot spots' exist which have dusts containing excessively high levels of particular metallic elements.

  18. Comparison of Lead Species in Household Dust Wipes, Soil, and Airborne Particulate Matter in El Paso, Texas, by X-Ray Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pingitore, N. E.; Clague, J.; Amaya, M. A.

    2006-12-01

    Understanding the interplay of indoor and outdoor sources of lead in an urban setting is one foundation in establishing risk for lead exposure in children in our cities. A household may be the source for lead contamination due to the deterioration of interior lead-based paint, or a sink if lead particles are tracked or blown into the home from such potential ambient sources as yard soil or urban street dust. In addressing this issue, X-Ray Absorption Spectroscopy (XAS) presents the opportunity to directly and quantitatively speciate lead at low concentrations in bulk samples. We performed XAS analyses on dust wipes from window sills or floors from 8 houses that exceeded Federal standards for lead in dust. We entered these data into a Principal Components Analysis (PCA) that also included El Paso environmental samples: lead-based paints, soils, and airborne particulate matter. A simple two-component mixing system accounted for more than 95% of the variance of this data set. Paint and lead oxide appear to be the principal components, with all the samples falling in a compositional range from pure paint to 75% paint, 25% lead oxide. Note that several different lead compounds are possible constituents of a given lead-based paint. The paints spread from one end out along perhaps a fifth of the range of the compositional axis, followed closely, but not overlapped, by the soil samples, which covered the remainder of the compositional range. Two of the dust wipes plotted within the paint range, and the remaining 6 dust wipes plotted randomly through the soil range. Samples of airborne particulate matter plotted in both the paint and soil ranges. These observations suggest that the lead on most of the dust wipes originated outside the house, probably from deteriorated exterior lead-based paint deposited in adjacent yards. This paint mixed with lead oxide present in the soil and entered the houses by the airborne route. The probable source of the oxide in the soil is former

  19. 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

    NASA Astrophysics Data System (ADS)

    Sakama, M.; Nagano, Y.; Kitade, T.; Shikino, O.; Nakayama, S.

    2014-06-01

    Radioactive fission product 131I 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, 134Cs and 137Cs 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-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 and those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of 134Cs and 137Cs 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-3) variation of stable cesium (133Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument.

  20. 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

    SciTech Connect

    Sakama, M.; Nagano, Y.; Kitade, T.; Shikino, O.; Nakayama, S.

    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 and 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.

  1. Airborne birch and grass pollen allergens in street-level shops.

    PubMed

    Holmquist, L; Weiner, J; Vesterberg, O

    2001-12-01

    Polluted urban outdoor air may be enriched with large amounts of submicronic respirable pollen allergen particles that penetrate into street-level shops. The objectives of the study were to map concentrations of birch and grass pollen allergens in indoor air of street-level shops and to explore the effect of electrostatic air cleaning under authentic working conditions, indoor air samples were collected in May and July 1999 in two shops. Allergens were quantified by a direct on sampling filter in solution (DOSIS) luminescence immunoassay. The average concentration of airborne indoor birch pollen allergen in the shop with air cleaning was estimated to be 20 +/- 9 SQ/m3 (mean +/- SD) compared to 31 +/- 17 SQ/m3 (mean +/- SD) of that without. The air cleaner reduced the indoor air birch pollen allergen concentration by on average 26 to 48% (P < 0.05). Corresponding figures for airborne indoor grass pollen allergen concentrations were 14 +/- 7 SQ/m3 and 17 +/- 8 SQ/m3, indicating a statistically non-significant (t-test) average 18% reduction of allergen by air cleaning. Excluding two observations with poor fit to the statistical model a significant (P < 0.05) average 27% reduction was obtained. Substantial amounts of airborne birch and grass pollen allergens may occur in street-level shops during flowering seasons. PMID:11761599

  2. Identification and prevalence of culturable mesophilic microfungi in house dust from 100 Danish homes. Comparison between airborne and dust-bound fungi.

    PubMed

    Gravesen, S

    1978-10-01

    In order to encircle possible allergen sources, fungi from house dust were cultivated and identified. Dust from vacuum cleaners was inoculated on Petri dishes containing V-8 agar with addition of penicillin and streptomycin to eliminate the bacterial flora. The number of genera identified were for the most part consistent with the genera trapped from the air. However, presumably owing to their dispersal biology it was demonstrated that members of Mucorales were much more frequently represented in the samples obtained by this method compared with gravimetric and volumetric measurements. The method is recommended as a simple way to demonstrate and identify the mould contents in house dust and as a tool for the identification of some of the real allergenic sources in house dust. PMID:362974

  3. Associations Between Subjective Symptoms and Serum Immunoglobulin E Levels During Asian Dust Events

    PubMed Central

    Otani, Shinji; Onishi, Kazunari; Mu, Haosheng; Hosoda, Takenobu; Kurozawa, Youichi; Ikeguchi, Masahide

    2014-01-01

    Asian dust is a seasonal meteorological phenomenon caused by the displacement of atmospheric pollutants from the Mongolian and Chinese deserts. Although the frequency of Asian dust events and atmospheric dust levels have steadily increased in the eastern Asia region, the effects on human health remain poorly understood. In the present study, the impact of Asian dust on human health was determined in terms of allergic reactions. A total of 25 healthy volunteers were tested for a relationship between serum immunoglobulin E (IgE) levels and subjective symptoms during a 3-day Asian dust event recorded in April 2012. They filled daily questionnaires on the severity of nasal, pharyngeal, ocular, respiratory, and skin symptoms by a self-administered visual analog scale. Serum levels of non-specific IgE and 33 allergen-specific IgE molecules were analyzed. Spearman rank-correlation analysis revealed significant positive associations between nasal symptom scores and 2 microbial-specific IgE levels (Penicillium and Cladosporium). Microbes migrate vast distances during Asian dust events by attaching themselves to dust particles. Therefore, some of these symptoms may be associated with type 1 allergic reactions to certain type of microbes. PMID:25075882

  4. Properdin Levels in the Sera of Rabbits Exposed to a Silica Dust Cloud

    PubMed Central

    MacNab, Gwen M.; Webster, Ian

    1962-01-01

    The properdin levels in the sera of rabbits exposed to a silica dust cloud for 19 weeks were investigated. The results show a decline in the properdin titres of the experimental animals up to the sixth week of exposure. After the fourteenth week of dusting, it was observed that the properdin levels of the rabbits were restored to normal. The significance of these findings is discussed. PMID:14468041

  5. Estimating outdoor and indoor dust lead levels from accidental bridge repair containment releases

    SciTech Connect

    Cohen, J.T.; Conway, R.F.

    1999-07-01

    A 1998 New York City Department of Transportation (NYCDOT) environmental impact statement (EIS) evaluated the proposed removal of deteriorated lead paint from NYCDOT-owned bridges. The EIS health risk assessment quantified the potential impact of particulate releases on blood lead levels among members of the public living and working near affected bridges. The risk assessment consisted of a fate and transport component and an exposure-dose component. The fate and transport component, modeled using the EPA's Industrial Source Complex (ISC3) model, calculated the impact of paint removal activities on ambient air lead concentrations and dust lead deposition rates. The exposure-dose component, modeled using EPA's Integrated Exposure Uptake Biokinetic (IEUBK) model, the Bowers et al. Adult Lead model, and the O'Flaherty lead model, calculated the impact of additional lead in air, street dust, interior house dust, and soil on blood lead levels, a conventional measure of body lead burden. The analysis was complicated because the ISC3 model provides a dust lead deposition rate ({micro}g/m{sup 2}-day), while the IEUBK, Bowers et al., and O'Flaherty models demand as input specification of dust lead concentrations ({micro}g lead per g dust). This paper describes a model developed for the EIS that quantifies long term average dust lead concentrations associated with typical bridge containment releases, and short term dust lead concentration spikes following worst case release events associated with bridge repair containment structure failures. The model reflects the influence of both lead and other debris associated with bridge repair activities, the contribution of background debris to street dust, and the impact of rainfall on removal of both lead and other material from the street dust reservoir.

  6. Airborne spectrophotometry of SN 1987A from 1.7 to 12.6 microns - Time history of the dust continuum and line emission

    NASA Technical Reports Server (NTRS)

    Wooden, Diane H.; Rank, David M.; Bregman, Jesse D.; Witteborn, Fred C.; Tielens, A. G. G. M.; Cohen, Martin; Pinto, Philip A.; Axelrod, Timothy S.

    1993-01-01

    Spectrophotometric observations of SN 1987A from the Kuiper Airborne Observatory are presented for five epochs at 60, 260, 415, 615, and 775 days after the explosion. The low-resolution (lambda/Delta lambda = 50-100) spectra of SN 1987A are combined with data from other wavelengths to model the continuum, subtract the continuum from the spectra to determine line strengths and reveal molecular bands, separate the atomic continuum radiation from the dust continuum, and derive constraints on the grain temperatures and optical depths. A scenario for the evolution of SN 1987A and that of the ejecta from which it arises is obtained on the basis of the analysis of the continuum emission.

  7. How important are atmospheric depressions and nocturnal low-level jets for North African dust emission?

    NASA Astrophysics Data System (ADS)

    Fiedler, Stephanie; Schepanski, Kerstin; Knippertz, Peter; Heinold, Bernd; Tegen, Ina

    2014-05-01

    Nocturnal low-level jets (NLLJs) and atmospheric depressions are known to generate wind speeds sufficient for dust emission in North Africa, but their relative importance is not well quantified. This work presents the first climatology of dust emission associated with theses phenomenon based on ERA-Interim data from the European Centre for Medium-Range Weather Forecasts. Depressions are detected as minima in the geopotential height at 925 hPa with a tracking algorithm. NLLJs are identified with a new automated detection algorithm. The results of the identification are connected with dust emissions from a dust model driven by 10m-winds from ERA-Interim. The findings highlight that atmospheric depressions are associated with 55 % of the dust emission in the annual and spatial mean. Regions south of the Atlas Mountains in spring and wide areas of North Africa during summer have contributions of up to 90 %. Lee cyclogenesis causes favourable conditions predominantly in spring while the heat low over West Africa dominates the climatology in summer. Migrating cyclones that live for more than two days are rare and associated with 4 % of the dust emission annually and spatially averaged. Maximum contributions of cyclones to dust emission are 25 % over eastern North Africa in spring. This result suggests that few depressions forming near the Atlas Mountains undergo the development to a long-lived and moving cyclone. Even though their total contribution to dust emission is small, the emission intensity is large. The climatological mean of the emission flux is exceeded by a factor of four to eight during cyclones. The presence of soil moisture during cyclones suppresses 10 % of the dust emission. The daytime fluxes are three to five times larger than at night. NLLJs are wind speed maxima at night that build at a few 100 m above the surface. Annually and spatially averaged, NLLJs form in 29 % of nights. Single regions and seasons, e.g. the Bodélé Depression in winter and the

  8. [Remote sensing of chlorophyll fluorescence at airborne level based on unmanned airship platform and hyperspectral sensor].

    PubMed

    Yang, Pei-Qi; Liu, Zhi-Gang; Ni, Zhuo-Ya; Wang, Ran; Wang, Qing-Shan

    2013-11-01

    The solar-induced chlorophyll fluorescence (ChlF) has a close relationship with photosynthetic and is considered as a probe of plant photosynthetic activity. In this study, an airborne fluorescence detecting system was constructed by using a hyperspectral imager on board an unmanned airship. Both Fraunhofer Line Discriminator (FLD) and 3FLD used to extract ChlF require the incident solar irradiance, which is always difficult to receive at airborne level. Alternative FLD (aFLD) can overcome the problem by selecting non-fluorescent emitter in the image. However, aFLD is based on the assumption that reflectance is identical around the Fraunhofer line, which is not realistic. A new method, a3FLD, is proposed, which assumes that reflectance varies linearly with the wavelength around Fraunhofer line. The result of simulated data shows that ChlF retrieval error of a3FLD is significantly lower than that of aFLD when vegetation reflectance varies near the Fraunhofer line. The results of hyperspectral remote sensing data with the airborne fluorescence detecting system show that the relative values of retrieved ChlF of 5 kinds of plants extracted by both aFLD and a3FLD are consistent with vegetation growth stage and the ground-level ChlF. The ChlF values of aFLD are about 15% greater than a3FLD. In addition, using aFLD, some non-fluorescent objects have considerable ChlF value, while a3FLD can effectively overcome the problem. PMID:24555390

  9. An Assessment of the Surface Longwave Direct Radiative Effect of Airborne Dust in Zhangye China During the Asian Monsoon Year Field Experiment (2008)

    NASA Technical Reports Server (NTRS)

    Hansell, Richard A.; Tsay, Si-Chee; Hsu, N. Christina; Ji, Qiang; Bell, Shaun W.; Holben, Brent N.; Ellsworth, Welton J.; Roush, Ted L.; Zhang, Wu; Huang, J.; Li, Zhanquing; Chen, Hongbin

    2012-01-01

    Tiny suspensions of solid particles or liquid droplets, called aerosols, hover in earth's atmosphere and can be found over just about anywhere including oceans, deserts, vegetated areas, and other global regions. Aerosols come in a variety of sizes, shapes, and compositions which depend on such factors as their origin and how long they have been in the atmosphere (i.e., their residence time). Some of the more common types of aerosols include mineral dust and sea salt which get lifted from the desert and ocean surfaces, respectively by mechanical forces such as strong winds. Depending on their size, aerosols will either fall out gravitationally, as in the case of larger particles, or will remain resident in the atmosphere where they can undergo further change through interactions with other aerosols and cloud particles. Not only do aerosols affect air quality where they pose a health risk, they can also perturb the distribution of radiation in the earth-atmosphere system which can inevitably lead to changes in our climate. One aerosol that has been in the forefront of many recent studies, particularly those examining its radiative effects, is mineral dust. The large spatial coverage of desert source regions and the fact that dust can radiatively interact with such a large part of the electromagnetic spectrum due to its range in particle size, makes it an important aerosol to study. Dust can directly scatter and absorb solar and infrared radiation which can subsequently alter the amount of radiation that would otherwise be present in the absence of dust at any level of the atmosphere like the surface. This is known as radiative forcing. At the surface dust can block incoming solar energy, however at infrared wavelengths, dust acts to partially compensate the solar losses. Evaluating the solar radiative effect of dust aerosols is relatively straightforward due in part to the relatively large signal-to-noise ratio in the measurements. At infrared wavelengths, on the

  10. Evaluation of SEVIRI Thermal Infra-Red data for airborne dust detection in an arid regions: the UAE case study

    NASA Astrophysics Data System (ADS)

    Gherboudj, I.; Parajuli, S. P.; Ghedira, H.

    2011-12-01

    Our interest in the study of the dust emission cycle over arid area results from the impacts that they have on the climate and atmospheric processes. Large dust concentration emitted even naturally or anthropogenic may reduce surface insolation by extinction of solar radiation. In addition, the knowledge of its spatio-temporal distribution is essential for monitoring several applications such as solar energy potential and health effect. Satellite-based remote sensing is an efficient tool to improve our understanding of the interaction of the desert dust and surrounding climate over regional and global scales with high frequency measurements. Thermal infrared (TIR) channels (3μm -15μm) of different satellites (MVIRI, AVHRR, MODIS, ADEOS-2/POLDER, TOMS, and MSG/SERIVI) were widely used for dust detection. Several dust detection and forecasting algorithms have been proposed based on these satellite data. However, the spatial and temporal variability of the physical characteristics of dust (concentrations, particle size distribution, location in the atmosphere, and chemical composition) has limited their estimations particularly with the dependence of the dust emission on the wind, soil water content, vegetation, and sediment availability. This study focuses on the analysis of the sensitivity of the MSG/SEVIRI TIR observation to dust generation, surface wind, soil moisture, and surface emissivity over the United Arab Emirates (UAE). SEVIRI observations were acquired in 2009 with temporal and spatial resolutions of 30 minutes and about 3km respectively. While the soil moisture is extracted from the AMSR-E data (1:30 AM and 1:30 PM) at spatial resolution of 25 km, the surface emissivity and Aerosol Optical Thickness were extracted from the MODIS products at spatial resolutions of 1 km and 100 km respectively. In coincidence with the satellites acquisitions, meteorological measurements were collected from seven met stations distributed over the selected study area (wind

  11. Comparative Benchmark Dose Modeling as a Tool to Make the First Estimate of Safe Human Exposure Levels to Lunar Dust

    NASA Technical Reports Server (NTRS)

    James, John T.; Lam, Chiu-wing; Scully, Robert R.

    2013-01-01

    Brief exposures of Apollo Astronauts to lunar dust occasionally elicited upper respiratory irritation; however, no limits were ever set for prolonged exposure ot lunar dust. Habitats for exploration, whether mobile of fixed must be designed to limit human exposure to lunar dust to safe levels. We have used a new technique we call Comparative Benchmark Dose Modeling to estimate safe exposure limits for lunar dust collected during the Apollo 14 mission.

  12. Effect of the aeration system on the levels of airborne microorganisms generated at wastewater treatment plants.

    PubMed

    Sánchez-Monedero, M A; Aguilar, M I; Fenoll, R; Roig, A

    2008-08-01

    Six different wastewater treatment plants were monitored in order to identify the main bioaerosol sources and to evaluate the effect of the aeration system used in the biological treatment (air diffusion, horizontal rotors and surface turbine aerators) on the airborne microorganism levels to which workers may be exposed. Air samples were collected by using a single stage impactor. Total count of mesophilic bacteria was used as the monitoring parameter to compare the impact of the aeration system on generic bacterial bioaerosols rather than a quantitative estimation for pathogens or fecal indicator microbes. In this study, pre-treatment, biological treatment and sludge thickening were the processes that generated the highest amount of bioaerosols. Aeration systems involving mechanical agitation of the wastewater, such as horizontal rotors and surface turbines, generated a larger amount of bioaerosols (between 450 and 4580CFU/m(3)) than air diffuser aerators (between 22 and 57CFU/m(3)). The levels of airborne bacteria generated by air diffusers were very similar to those registered at the background locations (lower than 50CFU/m(3)), unaffected by the activities taking place in the wastewater treatment plant. The use of air diffusers as an aeration system for the biological treatment would significantly minimise the potential biological hazard that wastewater treatment plant workers may be exposed to. PMID:18662822

  13. Screening-level assessment of airborne carcinogen risks from uncontrolled waste sites.

    PubMed

    Wolfinger, T F

    1989-04-01

    This report presents screening-level estimates of the general level of cancer risks arising from air emission from uncontrolled waste sites. Twenty-five National Priorities List sites were chosen randomly and airborne cancer risks estimated for each site in terms of risk to the maximally exposed individual (MEI risk), average individual risk (AEI risk), and population incidence. The estimates were developed using the EPA Human Exposure Model using assumptions on the rate and toxicity of site emissions. MEI risks ranged from 4 X 10(-9) to 1 X 10(-6) with an average of about 5 X 10(-7). AEI risks for individuals residing within four miles of the sites average about 10(-8), declining significantly for individuals residing at longer distances. Population incidence was low at all sites ranging from 2 X 10(-4) to 1 X 10(-2) cancer cases expected within 60 miles of the sites. Due to the uncertainties in this type of analysis and the underlying study assumptions, these results must be viewed with caution. Nonetheless, some preliminary conclusions can be drawn from the analysis, principally that airborne cancer risks from uncontrolled waste sites are likely to be small in most cases, with the greatest concern being maximally exposed individuals rather than the number of cancer cases expected in the exposed population. PMID:2723687

  14. Determining contamination level of heavy metals in road dust from busy traffic areas with different characteristics.

    PubMed

    Duong, Trang T T; Lee, Byeong-Kyu

    2011-03-01

    This study identified the levels and sources of heavy metal contamination in road dust from busy traffic areas in a typical industrial city in Korea. This study compared the total concentrations, as determined by aqua regia digestions and atomic absorption spectroscopy, of cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn) and nickel (Ni) in the road dust from areas with different characteristics such as traffic rotaries, downtown areas, circulation roads, and asphalt and concrete highways. The contamination levels of the heavy metals in the road dust were evaluated using the contamination factor and the degree of contamination. The contamination levels of the heavy metals in the road dust were highly dependent on traffic volume and atmospheric dispersion from traffic rotaries. Industrial emissions and the frequency of brake use and vehicles coming to a complete stop were additional factors that affected the contamination levels in downtown areas. The concrete highway had higher contamination levels of the heavy metals than the asphalt highway. Vehicle speed was also a strong contributing factor to the degree of contamination of heavy metals in the road dust from the circulation roads and highways. PMID:20937547

  15. How much North African dust emission is associated with breakdowns of nocturnal low-level jets?

    NASA Astrophysics Data System (ADS)

    Fiedler, S.; Schepanski, K.; Heinold, B.; Knippertz, P.; Tegen, I.

    2013-12-01

    Mineral dust aerosol has important impacts on atmospheric radiation transfer, optical properties and precipitability of clouds, as well as human health and eco-systems. Time, location and amount of dust emission are key factors for simulating the atmospheric life cycle of dust and its effects accurately. Dust emission is a non-linear function of surface properties, and the momentum transfer from the atmosphere to the Earth's surface. A phenomenon capable of mobilizing dust is the Nocturnal Low-Level Jet (NLLJ), a wind speed maximum at night caused by air accelerating due to reduced dynamical friction in the nocturnal boundary layer. Momentum from the NLLJ is transferred downwards by turbulence, predominantly during the following morning when surface heating erodes the nocturnal temperature inversion. While this breakdown of NLLJs has been suggested to be a main driver for dust storms in North Africa, a quantitative investigation based on analysis data is lacking. As part of the European Research Council funded 'Desert Storms' project, this work presents the first statistical analysis of the importance of NLLJs for the mineral dust amount emitted in North Africa. A new automated detection algorithm for NLLJs has been developed for analyzing the spatio-temporal characteristics and associated mineral dust emission amounts. The algorithm is applied to the European Centre for Medium-Range Weather Forecasts ERA-Interim re-analysis for 1979-2010. Near-surface wind speed and soil moisture from ERA-interim drive an off-line dust model for calculating associated dust emission fluxes. Annually and spatially averaged, NLLJs form in 29 % of the nights in North Africa. The areal distribution of NLLJs highlights their frequent occurrence along the margins of the Saharan heat-low in summer, and in regions affected by mountain channeling like the Bodélé Depression, Chad, predominantly in winter. In these seasonally varying hotspots NLLJs are identified in 40-80 % of the nights

  16. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade

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

    PubMed Central

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

    2015-01-01

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

  18. Modeling Human Exposure Levels to Airborne Volatile Organic Compounds by the Hebei Spirit Oil Spill

    PubMed Central

    Kim, Jong Ho; Kwak, Byoung Kyu; Ha, Mina; Cheong, Hae-Kwan

    2012-01-01

    Objectives The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. Methods We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. Results Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, ortho- meta- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. Conclusions The extent of airborne exposure was clearly not the same as that for normal conditions. PMID:22468262

  19. Associations between brominated flame retardants in house dust and hormone levels in men.

    PubMed

    Johnson, Paula I; Stapleton, Heather M; Mukherjee, Bhramar; Hauser, Russ; Meeker, John D

    2013-02-15

    Brominated flame retardants (BFRs) are used in the manufacture of a variety of materials and consumer products in order to meet fire safety standards. BFRs may persist in the environment and have been detected in wildlife, humans and indoor dust and air. Some BFRs have demonstrated endocrine and reproductive effects in animals, but human studies are limited. In this exploratory study, we measured serum hormone levels and flame retardant concentrations [31 polybrominated diphenyl ether (PBDE) congeners and 6 alternate flame retardants] in house dust from men recruited through a US infertility clinic. PBDE congeners in dust were grouped by commercial mixtures (i.e. penta-, octa- and deca-BDE). In multivariable linear regression models adjusted by age and body mass index (BMI), significant positive associations were found between house dust concentrations of pentaBDEs and serum levels of free T4, total T3, estradiol, and sex hormone binding globulin (SHBG), along with an inverse association with follicle stimulating hormone (FSH). There were also positive associations of octaBDE concentrations with serum free T4, thyroid stimulating hormone (TSH), luteinizing hormone (LH) and testosterone and an inverse association of decaBDE concentrations with testosterone. Hexabromocyclododecane (HBCD) was associated with decreased SHBG and increased free androgen index. Dust concentrations of bis-tribromophenoxyethane (BTBPE) and tetrabromo-diethylhexylphthalate (TBPH) were positively associated with total T3. These findings are consistent with our previous report of associations between PBDEs (BDE 47, 99 and 100) in house dust and hormone levels in men, and further suggest that exposure to contaminants in indoor dust may be leading to endocrine disruption in men. PMID:23333513

  20. Studies of the level of farmers' exposure to dust on private farms - based on fraction analyses.

    PubMed

    Buczaj, Agnieszka

    2008-01-01

    Studies of the level of exposure to dust among farmers on private farms covered the measurements of dustiness while they performed work activities from the aspect of farmer's exposure to individual fractions of the dust inhaled and potentially deposited in individual sections of the airways. The measurements were carried out in the respiratory zone while performing activities contributing to working processes in mixed agricultural production on private farms in an annual work cycle. The article presents the results of studies of the concentrations of inhalable, extrathoracic, thoracic, thoraco-bronchial and alveolic fractions, which allowed the assessment of the percentage distribution of dust deposited in individual sections of the airways, and enabled the estimation of an annual farmers' exposure to individual dust fractions while performing specific work activities on farms. The results of the assessment of farmers' annual exposure to individual fractions of dust indicated that the activities for which the highest values of mean annual weighted concentrations were noted, with respect to all fractions, were: sorting and packing of potatoes, harvesting cereals with a combine harvester, grain crushing, potato digging, and tending stock in cattle and swine breeding. The results obtained will allow the expansion of knowledge concerning the effect of agricultural dust on the human body, and enable the determination of the effect of dust deposited in individual sections of the respiratory system on the state of health of farmers. In future, this will also allow the development of the criteria of hygienic evaluation for dust penetrating into the region of the chest. PMID:18581983

  1. Atmospheric dust and acid rain

    SciTech Connect

    Hedin, L.O.; Likens, G.E.

    1996-12-01

    Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid rain and atmospheric dust? Suggestions range from the improbable to the feasible. One reasonable suggestion is to reduce emissions of acidic pollutants to levels that can be buffered by natural quantities of basic compounds in the atmosphere; such a goal would mean continued reductions in sulfur dioxide and nitrogen oxides, perhaps even greater than those prescribed in the 1990 Amendments to the Clean Air Act in the U.S. 5 figs.

  2. Endotoxin, coliform, and dust levels in various types of rodent bedding.

    PubMed

    Whiteside, Tanya E; Thigpen, Julius E; Kissling, Grace E; Grant, Mary G; Forsythe, Diane

    2010-03-01

    Endotoxins in grain dust, household dust, and animal bedding may induce respiratory symptoms in rodents and humans. We assayed the endotoxin, coliform, and dust levels in 20 types of rodent bedding. Endotoxin concentrations were measured by using a commercial test kit, coliform counts were determined by using conventional microbiologic procedures, and dust content was evaluated by using a rotating-tapping shaker. Paper bedding types contained significantly less endotoxin than did other bedding types; the highest levels of endotoxin were detected in hardwood and corncob beddings. The range of endotoxin content for each bedding type was: corncob bedding, 1913 to 4504 endotoxin units per gram (EU/g); hardwood bedding, 3121 to 5401 EU/g; corncob-paper mixed bedding, 1586 to 2416 EU/g; and paper bedding, less than 5 to 105 EU/g. Coliform counts varied from less than 10 to 7591 cfu/g in corncob beddings, 90 to 4010 cfu/g in corncob-paper mixed beddings, less than 10 to 137 cfu/g in hardwood beddings, and less than 10 cfu/g in paper beddings. Average dust content was less than 0.15% in all commercial bedding types. We conclude that paper bedding is the optimal bedding type for conducting LPS inhalation studies and that rodent bedding containing high levels of endotoxin may alter the results of respiratory and immunologic studies in rodents. PMID:20353693

  3. Metal levels in indoor and outdoor dust in Riyadh, Saudi Arabia

    SciTech Connect

    Al-Rajhi, M.A.; Seaward, M.R.D.; Al-Aamer, A.S.

    1996-08-01

    Concentrations of Cd, Cr, Cu, Li, Ni, Pb, and Zn of outdoor and indoor dusts in Riyadh, Saudi Arabia, have been investigated in relation to particle sizes 0.04-0.08 mm using Atomic Absorption Spectroscopy (AAS). Although the results showed relatively low contamination in general, the old industrial area had appreciably high levels of toxic metals and there relatively high Pb levels near motorways. Mean concentrations of outdoor dusts for Cd, Cr, Cu, Li, Ni, Pb, and Zn were 2.5 {+-} 0.3, 35.1 {+-}2.7, 93.9 {+-}41.9, 4.6 {+-} 0.3, 43.9 {+-} 5.6, 1762 {+-} 593, and 443 {+-} 223 {mu}g.g{sup -1}, respectively, and mean concentrations of indoor dusts were 2.9 {+-} 1.1, 69.2{+-} 16.5, 271 {+-} 140, 6.2 {+-} 0.5, 52.9 {+-} 17.7, 639 {+-} 279, and 547 {+-} 197 {mu}g.g{sup -1}, respectively. The main source of these heavy metals, in both outdoor and indoor dusts, was from automobile emission. The relationship between indoor and outdoor dusts were investigated. In view of the high levels of some of these toxic metals, these can be considered a significant hand-to-mouth source of exposure, especially for children. 28 refs., 3 fig., 4 tab.

  4. Lead concentration in Hong Kong roadside dust after reduction of lead level in petrol

    SciTech Connect

    Chan, G.Y.; Chui, V.W.; Wong, M.H. )

    1989-06-01

    Samples of roadside dust were collected from 30 sites in Hong Kong. The total concentrations of 10 metals in the samples were analyzed, and the correlation coefficients among the metal contents and the annual average daily traffic (AADT) in 1986 were determined. Pb was found to have a significant correlation (P less than 0.01) with AADT. No correlation was found between Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, and Zn with respect to AADT. A general decrease in the level of Pb in roadside dust in the past few years has been observed since the reduction in the level of lead in petrol.

  5. Harvesting tree biomass at the stand level to assess the accuracy of field and airborne biomass estimation in savannas.

    PubMed

    Colgan, Matthew S; Asner, Gregory P; Swemmer, Tony

    2013-07-01

    Tree biomass is an integrated measure of net growth and is critical for understanding, monitoring, and modeling ecosystem functions. Despite the importance of accurately measuring tree biomass, several fundamental barriers preclude direct measurement at large spatial scales, including the facts that trees must be felled to be weighed and that even modestly sized trees are challenging to maneuver once felled. Allometric methods allow for estimation of tree mass using structural characteristics, such as trunk diameter. Savanna trees present additional challenges, including limited available allometry and a prevalence of multiple stems per individual. Here we collected airborne lidar data over a semiarid savanna adjacent to the Kruger National Park, South Africa, and then harvested and weighed woody plant biomass at the plot scale to provide a standard against which field and airborne estimation methods could be compared. For an existing airborne lidar method, we found that half of the total error was due to averaging canopy height at the plot scale. This error was eliminated by instead measuring maximum height and crown area of individual trees from lidar data using an object-based method to identify individual tree crowns and estimate their biomass. The best object-based model approached the accuracy of field allometry at both the tree and plot levels, and it more than doubled the accuracy compared to existing airborne methods (17% vs. 44% deviation from harvested biomass). Allometric error accounted for less than one-third of the total residual error in airborne biomass estimates at the plot scale when using allometry with low bias. Airborne methods also gave more accurate predictions at the plot level than did field methods based on diameter-only allometry. These results provide a novel comparison of field and airborne biomass estimates using harvested plots and advance the role of lidar remote sensing in savanna ecosystems. PMID:23967584

  6. Airborne trichloramine (NCl(3)) levels and self-reported health symptoms in indoor swimming pool workers: dose-response relationships.

    PubMed

    Fantuzzi, Guglielmina; Righi, Elena; Predieri, Guerrino; Giacobazzi, Pierluigi; Petra, Berchotd; Aggazzotti, Gabriella

    2013-01-01

    The hypothesis that attendance at indoor chlorinated swimming pool is a risk factor for irritative ocular and respiratory symptoms and bronchial asthma is well known in literature, although epidemiological evidence is still inconclusive. The aim of this study was to evaluate the association between airborne trichloramine (NCl(3)) levels and irritative symptoms in swimming pool employees in order to obtain detailed data regarding dose-response relationships and to identify the airborne NCl(3) exposure level, if any, without health effects. A total of 20 indoor swimming pools in the Emilia Romagna region of Italy were included in the study. Information about the health status of 128 employees was collected using a self-administered questionnaire. Exposure to airborne NCl(3) was evaluated in indoor swimming pools by a modified DPD/KI method. The results of the study evidenced a mean value of airborne NCl(3) of 0.65±0.20 mg/m(3) (ranging from 0.20 to 1.02 mg/m(3)). Both ocular and upper respiratory symptoms, in particular red eyes, runny nose, voice loss and cold symptoms, were declared more frequently by lifeguards and trainers when compared with employees working in other areas of the facility (office, cafe, and so on). Pool attendants exposed to airborne NCl(3) levels of >0.5 mg/m(3) experienced higher risks for runny nose (OR: 2.91; 95% CI: 1.22-6.93) red eyes (OR: 3.16; 95% CI: 1.46-6.82), voice loss (OR: 3.56; 95% CI: 1.60-7.95) and itchy eyes (OR: 2.23; 95% CI: 1.04-4.78) than other employees. Moreover, red eyes, itchy eyes, runny nose and voice loss are related to airborne NCl(3) levels, with strong dose-response relationships. In conclusion, this study shows that lifeguards and trainers experience ocular and respiratory irritative symptoms more frequently than employees not exposed. Irritative symptoms become significant starting from airborne NCl(3) levels of >0.5 mg/m(3), confirming that the WHO-recommended value can be considered protective in

  7. Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India.

    NASA Astrophysics Data System (ADS)

    Sharma, Disha; Kulshrestha, Umesh

    Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India. The Critical Load approach alongwith integrated assessment models has been used in the European nations for policy formations to reduce acidic emissions. This unique approach was applied to assess the of vulnerability of natural systems to the present day atmospheric pollution scenario. The calculated values of critical loads of sulphur ( 225 - 275 eq/ha/yr) and nitrogen (298 - 303 eq/ha/yr), for the soil system in Delhi, were calculated with respect to Anjan grass, Hibiscus and Black siris. The present loads of sulphur (PL(S) = 26.40 eq/ha/yr) and nitrogen (PL(N) = 36.51 eq/ha/yr) were found to be much lower than their critical loads without posing any danger of atmospheric acidic deposition on the soil systems. The study indicated that the system is still protective due to high pH of soil. The nature of buffering capability of calcium derived from soil dust can be considered as a natural tool to combat acidification in the Indian region. The results showed that the pollution status in Delhi is still within the safe limits. However, at the pace at which the city is growing, it is likely that in coming decades, it may exceed these critical values. In order to set deposition limits and avoid adverse effects of acidic deposition this approach can be applied in India too. Such approach is very useful, not only in abating pollution but also in devising means of cost optimal emission abatement strategies.

  8. Levels and predictors of airborne and internal exposure to manganese and iron among welders.

    PubMed

    Pesch, Beate; Weiss, Tobias; Kendzia, Benjamin; Henry, Jana; Lehnert, Martin; Lotz, Anne; Heinze, Evelyn; Käfferlein, Heiko Udo; Van Gelder, Rainer; Berges, Markus; Hahn, Jens-Uwe; Mattenklott, Markus; Punkenburg, Ewald; Hartwig, Andrea; Brüning, Thomas

    2012-01-01

    We investigated airborne and internal exposure to manganese (Mn) and iron (Fe) among welders. Personal sampling of welding fumes was carried out in 241 welders during a shift. Metals were determined by inductively coupled plasma mass spectrometry. Mn in blood (MnB) was analyzed by graphite furnace atom absorption spectrometry. Determinants of exposure levels were estimated with multiple regression models. Respirable Mn was measured with a median of 62 (inter-quartile range (IQR) 8.4-320) μg/m(3) and correlated with Fe (r=0.92, 95% CI 0.90-0.94). Inhalable Mn was measured with similar concentrations (IQR 10-340 μg/m(3)). About 70% of the variance of Mn and Fe could be explained, mainly by the welding process. Ventilation decreased exposure to Fe and Mn significantly. Median concentrations of MnB and serum ferritin (SF) were 10.30 μg/l (IQR 8.33-13.15 μg/l) and 131 μg/l (IQR 76-240 μg/l), respectively. Few welders were presented with low iron stores, and MnB and SF were not correlated (r=0.07, 95% CI -0.05 to 0.20). Regression models revealed a significant association of the parent metal with MnB and SF, but a low fraction of variance was explained by exposure-related factors. Mn is mainly respirable in welding fumes. Airborne Mn and Fe influenced MnB and SF, respectively, in welders. This indicates an effect on the biological regulation of both metals. Mn and Fe were strongly correlated, whereas MnB and SF were not, likely due to higher iron stores among welders. PMID:22377681

  9. Airborne microorganisms in the African desert dust corridor over the mid-Atlantic ridge, Ocean Drilling Program, Leg 209

    USGS Publications Warehouse

    Griffin, Dale W.; Westphal, Douglas L.; Gray, Michael A.

    2006-01-01

    The objective of this study was to enhance our understanding of the fate and trans-Atlantic transport of dustborne microorganisms from Northern Africa to the Caribbean and Americas, and more specifically to determine if culturable populations could be detected at a mid-ocean site, closer to the source of dust relative to land-based Caribbean sites, during the early summer months of May and June. Between the dates of 22 May and 30 June 2003, daily air samples were collected and evaluated for the presence of culturable bacterial and fungal colony-forming units (CFU). Here we report a statistically significant correlation between daily atmospheric CFU counts at a mid-ocean research site (???15??N, 45??W) and daily desert dust concentrations as determined by the U.S. Navy's Naval Aerosol Analysis and Prediction System (NAAPS) Global Aerosol Model (Honrath et al. (2004). Journal of Geophysical Research, 109; Johnson et al. (2003). Global Biogeochemical Cycles, 17, 1063; Reid et al. (2004). Geophysical Research Letters, 31; Schollaert, Yoder, Westphal, & O'Reilly (2003). Journal of Geophysical Research, 108, 3191). ?? Springer Science+Business Media B.V. 2006.

  10. Airborne Petcoke Dust is a Major Source of Polycyclic Aromatic Hydrocarbons in the Athabasca Oil Sands Region.

    PubMed

    Zhang, Yifeng; Shotyk, William; Zaccone, Claudio; Noernberg, Tommy; Pelletier, Rick; Bicalho, Beatriz; Froese, Duane G; Davies, Lauren; Martin, Jonathan W

    2016-02-16

    Oil sands mining has been linked to increasing atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in the Athabasca oil sands region (AOSR), but known sources cannot explain the quantity of PAHs in environmental samples. PAHs were measured in living Sphagnum moss (24 sites, n = 68), in sectioned peat cores (4 sites, n = 161), and snow (7 sites, n = 19) from ombrotrophic bogs in the AOSR. Prospective source samples were also analyzed, including petroleum coke (petcoke, from both delayed and fluid coking), fine tailings, oil sands ore, and naturally exposed bitumen. Average PAH concentrations in near-field moss (199 ng/g, n = 11) were significantly higher (p = 0.035) than in far-field moss (118 ng/g, n = 13), and increasing temporal trends were detected in three peat cores collected closest to industrial activity. A chemical mass-balance model estimated that delayed petcoke was the major source of PAHs to living moss, and among three peat core the contribution to PAHs from delayed petcoke increased over time, accounting for 45-95% of PAHs in contemporary layers. Petcoke was also estimated to be a major source of vanadium, nickel, and molybdenum. Scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed large petcoke particles (>10 μm) in snow at near-field sites. Petcoke dust has not previously been considered in environmental impact assessments of oil sands upgrading, and improved dust control from growing stockpiles may mitigate future risks. PMID:26771587

  11. Coupling Mars' Dust and Water Cycles: Effects on Dust Lifting Vigor, Spatial Extent and Seasonality

    NASA Technical Reports Server (NTRS)

    Kahre, M. A.; Hollingsworth, J. L.; Haberle, R. M.; Montmessin, F.

    2012-01-01

    The dust cycle is an important component of Mars' current climate system. Airborne dust affects the radiative balance of the atmosphere, thus greatly influencing the thermal and dynamical state of the atmosphere. Dust raising events on Mars occur at spatial scales ranging from meters to planet-wide. Although the occurrence and season of large regional and global dust storms are highly variable from one year to the next, there are many features of the dust cycle that occur year after year. Generally, a low-level dust haze is maintained during northern spring and summer, while elevated levels of atmospheric dust occur during northern autumn and winter. During years without global-scale dust storms, two peaks in total dust loading were observed by MGS/TES: one peak occurred before northern winter solstice at Ls 200-240, and one peak occurred after northern winter solstice at L(sub s) 305-340. These maxima in dust loading are thought to be associated with transient eddy activity in the northern hemisphere, which has been observed to maximize pre- and post-solstice. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading. Interactive dust cycle studies typically have not included the formation of water ice clouds or their radiative effects. Water ice clouds can influence the dust cycle by scavenging dust from atmosphere and by interacting with solar and infrared radiation

  12. Repetitive Immunoassay with a Surface Acoustic Wave Device and a Highly Stable Protein Monolayer for On-Site Monitoring of Airborne Dust Mite Allergens.

    PubMed

    Toma, Koji; Miki, Daisuke; Kishikawa, Chisato; Yoshimura, Naoyuki; Miyajima, Kumiko; Arakawa, Takahiro; Yatsuda, Hiromi; Mitsubayashi, Kohji

    2015-10-20

    This work describes a sensor to be incorporated into the on-site monitoring system of airborne house dust mite (HDM) allergens. A surface acoustic wave (SAW) device was combined with self-assembled monolayers of a highly stable antibody capture protein on the SAW surface that have high resistance to pH change. A sandwich assay was used to measure a HDM allergen, Der f 1 derived from Dermatophagoides farinae. Capture antibodies were cross-linked to a protein G based capture layer (ORLA85) on the sensor surface, thereby only Der f 1 and detection antibodies were regenerated by changing pH, resulting in fast repetition of the measurement. The sensor was characterized through 10 repetitive measurements of Der f 1, which demonstrated high reproducibility of the sensor with the coefficient of variation of 5.6%. The limit of detection (LOD) of the sensor was 6.1 ng·mL(-1), encompassing the standard (20 ng·mL(-1)) set by the World Health Organization. Negligible sensor outputs were observed for five different major allergens including other HDM allergens which tend to have cross-reactivity to Der f 1 and their mixtures with Der f 1. Finally, the sensor lifetime was evaluated by conducting three measurements per day, and the sensor output did not substantially change for 4 days. These characteristics make the SAW immunosensor a promising candidate for incorporation into on-site allergen monitoring systems. PMID:26378678

  13. Temporal Variability of the Bioaerosol Background at a Subway Station: Concentration Level, Size Distribution, and Diversity of Airborne Bacteria

    PubMed Central

    Dybwad, Marius; Skogan, Gunnar

    2014-01-01

    Naturally occurring bioaerosol environments may present a challenge to biological detection-identification-monitoring (BIODIM) systems aiming at rapid and reliable warning of bioterrorism incidents. One way to improve the operational performance of BIODIM systems is to increase our understanding of relevant bioaerosol backgrounds. Subway stations are enclosed public environments which may be regarded as potential bioterrorism targets. This study provides novel information concerning the temporal variability of the concentration level, size distribution, and diversity of airborne bacteria in a Norwegian subway station. Three different air samplers were used during a 72-h sampling campaign in February 2011. The results suggested that the airborne bacterial environment was stable between days and seasons, while the intraday variability was found to be substantial, although often following a consistent diurnal pattern. The bacterial levels ranged from not detected to 103 CFU m−3 and generally showed increased levels during the daytime compared to the nighttime levels, as well as during rush hours compared to non-rush hours. The airborne bacterial levels showed rapid temporal variation (up to 270-fold) on some occasions, both consistent and inconsistent with the diurnal profile. Airborne bacterium-containing particles were distributed between different sizes for particles of >1.1 μm, although ∼50% were between 1.1 and 3.3 μm. Anthropogenic activities (mainly passengers) were demonstrated as major sources of airborne bacteria and predominantly contributed 1.1- to 3.3-μm bacterium-containing particles. Our findings contribute to the development of realistic testing and evaluation schemes for BIODIM equipment by providing information that may be used to simulate operational bioaerosol backgrounds during controlled aerosol chamber-based challenge tests with biological threat agents. PMID:24162566

  14. Investigating the spatial distribution of water levels in the Mackenzie Delta using airborne LiDAR

    USGS Publications Warehouse

    Hopkinson, C.; Crasto, N.; Marsh, P.; Forbes, D.; Lesack, L.

    2011-01-01

    Airborne light detection and ranging (LiDAR) data were used to map water level (WL) and hydraulic gradients (??H/??x) in the Mackenzie Delta. The LiDAR WL data were validated against eight independent hydrometric gauge measurements and demonstrated mean offsets from - 0??22 to + 0??04 m (??< 0??11). LiDAR-based WL gradients could be estimated with confidence over channel lengths exceeding 5-10 km where the WL change exceeded local noise levels in the LiDAR data. For the entire Delta, the LiDAR sample coverage indicated a rate of change in longitudinal gradient (??2H/??x) of 5??5 ?? 10-10 m m-2; therefore offering a potential means to estimate average flood stage hydraulic gradient for areas of the Delta not sampled or monitored. In the Outer Delta, within-channel and terrain gradient measurements all returned a consistent estimate of - 1 ?? 10-5 m m-1, suggesting that this is a typical hydraulic gradient for the downstream end of the Delta. For short reaches (<10 km) of the Peel and Middle Channels in the middle of the Delta, significant and consistent hydraulic gradient estimates of - 5 ?? 10-5 m m-1 were observed. Evidence that hydraulic gradients can vary over short distances, however, was observed in the Peel Channel immediately upstream of Aklavik. A positive elevation anomaly (bulge) of > 0??1 m was observed at a channel constriction entering a meander bend, suggesting a localized modification of the channel hydraulics. Furthermore, water levels in the anabranch channels of the Peel River were almost 1 m higher than in Middle Channel of the Mackenzie River. This suggests: (i) the channels are elevated and have shallower bank heights in this part of the delta, leading to increased cross-delta and along-channel hydraulic gradients; and/or (ii) a proportion of the Peel River flow is lost to Middle Channel due to drainage across the delta through anastamosing channels. This study has demonstrated that airborne LiDAR data contain valuable information describing

  15. Monitoring Airborne Dust from Source to Sink Using the e-Deep Blue Aerosol Products from VIIRS, MODIS, and Seawifs

    NASA Astrophysics Data System (ADS)

    Carletta, N.; Hsu, N. Y. C.; Bettenhausen, C.; Sayer, A. M.; Lee, J.

    2014-12-01

    Mineral dust sources are typically located in very bright, arid desert regions across the globe. In the past, aerosol retrieval algorithms were unable to properly handle these bright surfaces which lead to large, persistent data gaps. In order to eliminate these gaps, the Deep Blue algorithm was developed and first entered into the MODIS operational stream in Collection 5.1. Since then, the Deep Blue algorithm has evolved to retrieve not only over bright surfaces, but also vegetated surfaces. This updated algorithm has been named the enhanced Deep Blue (e-Deep Blue) algorithm and has been successfully applied to reflectances from the Sea-viewing, Wide Field-of-view Sensor (SeaWiFS, 1997-2010), Moderate Resolution Imaging Spectroradiometer (MODIS, 2000/2002-present), and now the Visible Infrared Imaging Radiometer Suite (VIIRS, 2012-present) aboard the Suomi-NPP platform. This algorithm has been partnered with a new over-ocean algorithm for our SeaWiFS and VIIRS datasets. Due to the broad swath of VIIRS, daily global coverage is achieved at higher spatial resolution compared to MODIS and SeaWiFS. Thus, the evolution of dust can be tracked from source to sink, across both land and ocean using these satellite products. We introduce the basics of the e-Deep Blue algorithm along with our preliminary VIIRS e-Deep Blue products, including aerosol optical thickness at 550nm and Ǻngström exponent. Validation with AErosol RObotic NETwork (AERONET) data are also presented along with the intercomparisons between VIIRS Deep Blue and other satellite products.

  16. Saharan dust contribution to PM levels: The EC LIFE+ DIAPASON project

    NASA Astrophysics Data System (ADS)

    Gobbi, G. P.; Wille, H.; Sozzi, R.; Angelini, F.; Barnaba, F.; Costabile, F.; Frey, S.; Bolignano, A.; Di Giosa, A.

    2012-04-01

    The contribution of Saharan-dust advections to both daily and annual PM average values can be significant all over Southern Europe. The most important effects of dust on the number of PM exceedances are mostly observed in polluted areas and large cities. While a wide literature exists documenting episodes of Saharan dust transport towards the Euro-Mediterranean region and Europe in general, a limited number of studies are still available providing statistically significant results on the impact of Saharan dust on the particulate matter loads over the continent. A four-year (2001-2004) study performed in Rome (Italy) found these events to contribute to the average ground PM10 with about 15±10 µg/m3 on about 17% of the days in a year. Since the PM10 yearly average of many traffic stations in Rome is close to 40 μg/m3, these events can cause the PM10 concentration to exceed air quality limit values (50 μg/m3 as daily average) set by the EU Air Quality Directive 2008/50/EC. Although the European legislation allows Member States to subtract the contribution of natural sources before counting PM10 exceedances, definition of an optimal methodology to quantitatively assess such contribution is still in progress. On the basis of the current European Guidelines on the assessment of natural contributions to PM, the DIAPASON project ("Desert-dust Impact on Air quality through model-Predictions and Advanced Sensors ObservatioNs", recently funded under the EC LIFE+ program) has been formulated to provide a robust, user-oriented methodology to assess the presence of desert dust and its contribution to PM levels. To this end, in addition to satellite-based data and model forecasts, the DIAPASON methodology will employ innovative and affordable technologies, partly prototyped within the project itself, as an operational Polarization Lidar-Ceilometer (laser radar) capable of detecting and profiling dust clouds from the ground up to 10 km altitude. The DIAPASON Project (2011

  17. PAHs in indoor dust samples in Shanghai's universities: levels, sources and human exposure.

    PubMed

    Peng, Huan; Yang, Yi; Liu, Min; Zhou, John L

    2012-10-01

    Given the significant amount of time people spend indoors, the occurrence of polycyclic aromatic hydrocarbons (PAHs) in indoor dust and their potential risks are of great concern. In the present study, ten dust samples from lecture theatres and twelve samples from dining halls were collected from university campuses in Shanghai to investigate the PAH levels, possible sources and human exposure. The total concentrations of 18 PAHs ranged from 9.84 to 21.44 μg/g for dust samples from lecture theatres, and 9.63-44.13 μg/g for samples from dining halls. Total PAH concentrations in indoor dust samples showed a better correlation to black carbon compared to total organic carbon contents. PAHs in dining halls samples showed a similar distribution pattern with that of commercial kitchen air, which indicated that cooking activities could contribute most of the PAHs found in dining halls. Principal component analysis revealed both petrogenic and pyrogenic sources. The potential health risk for PAHs was assessed in terms of BaP equivalent carcinogenic power and estimated daily intake (EDI). Relatively high EDI values compared to other studies suggested that PAHs posed a potential threat to human health in indoor environments at Shanghai's universities. PMID:22527117

  18. High levels of polybrominated diphenyl ethers in vacuum cleaner dust from California fire stations.

    PubMed

    Shen, Beverly; Whitehead, Todd P; McNeel, Sandra; Brown, F Reber; Dhaliwal, Joginder; Das, Rupali; Israel, Leslie; Park, June-Soo; Petreas, Myrto

    2015-04-21

    Firefighters are exposed to chemicals during fire events and may also experience chemical exposure in their fire stations. Dust samples from used vacuum cleaner bags were collected from 20 fire stations in California and analyzed for polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) using gas chromatography-mass spectrometry. Median dust concentrations were higher for PBDEs (e.g., 47 000 ng/g for BDE-209) than for PAHs (e.g., 220 ng/g for benzo[a]pyrene) or PCBs (e.g., 9.3 ng/g for PCB-180). BDE-209 concentrations in dust from California fire stations were among the highest of any previously documented homes or occupational settings in the world. We examined factors such as the frequency of emergency responses, the number of fire vehicles on site, and building age, but we could not account for the high levels of BDE-209 observed in fire station dust. Based on the findings of our pilot study, we hypothesize that possible sources of BDE-209 in fire stations include contaminated ash tracked back from fire events via boots, clothing, and other equipment as well as specialized equipment treated with BDE-209, including turnout gear and fire vehicles. We suggest possible follow-up studies to confirm these hypotheses. PMID:25798547

  19. 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

  20. Effects of physical interventions on house dust mite allergen levels in carpet, bed, and upholstery dust in low-income, urban homes.

    PubMed Central

    Vojta, P J; Randels, S P; Stout, J; Muilenberg, M; Burge, H A; Lynn, H; Mitchell, H; O'Connor, G T; Zeldin, D C

    2001-01-01

    House dust mite allergen exposure is a postulated risk factor for allergic sensitization, asthma development, and asthma morbidity; however, practical and effective methods to mitigate these allergens from low-income, urban home environments remain elusive. The purpose of this study was to assess the feasibility and effectiveness of physical interventions to mitigate house dust mite allergens in this setting. Homes with high levels of house dust mite allergen (Der f 1 + Der p 1 > or = 10 microg/g dust by enzyme-linked immunosorbent assay) in the bed, bedroom carpet, and/or upholstered furniture were enrolled in the study. Carpets and upholstered furniture were subjected to a single treatment of either dry steam cleaning plus vacuuming (carpet only) or intensive vacuuming alone. Bed interventions consisted of complete encasement of the mattress, box spring, and pillows plus either weekly professional or in-home laundering of nonencased bedding. Dust samples were collected at baseline and again at 3 days (carpet and upholstery only) and 2, 4, and 8 weeks posttreatment. We compared pretreatment mean allergen concentrations and loads to posttreatment values and performed between-group analyses after adjusting for differences in the pretreatment means. Both dry steam cleaning plus vacuuming and vacuuming alone resulted in a significant reduction in carpet house dust mite allergen concentration and load (p < 0.05). Levels approached pretreatment values by 4 weeks posttreatment in the intensive vacuuming group, whereas steam cleaning plus vacuuming effected a decrease that persisted for up to 8 weeks. Significant decreases in bed house dust mite allergen concentration and load were obtained in response to encasement and either professional or in-home laundering (p < 0.001). Between-group analysis revealed significantly less postintervention house dust mite allergen load in professionally laundered compared to home-laundered beds (p < 0.05). Intensive vacuuming and dry

  1. Effects of physical interventions on house dust mite allergen levels in carpet, bed, and upholstery dust in low-income, urban homes.

    PubMed

    Vojta, P J; Randels, S P; Stout, J; Muilenberg, M; Burge, H A; Lynn, H; Mitchell, H; O'Connor, G T; Zeldin, D C

    2001-08-01

    House dust mite allergen exposure is a postulated risk factor for allergic sensitization, asthma development, and asthma morbidity; however, practical and effective methods to mitigate these allergens from low-income, urban home environments remain elusive. The purpose of this study was to assess the feasibility and effectiveness of physical interventions to mitigate house dust mite allergens in this setting. Homes with high levels of house dust mite allergen (Der f 1 + Der p 1 > or = 10 microg/g dust by enzyme-linked immunosorbent assay) in the bed, bedroom carpet, and/or upholstered furniture were enrolled in the study. Carpets and upholstered furniture were subjected to a single treatment of either dry steam cleaning plus vacuuming (carpet only) or intensive vacuuming alone. Bed interventions consisted of complete encasement of the mattress, box spring, and pillows plus either weekly professional or in-home laundering of nonencased bedding. Dust samples were collected at baseline and again at 3 days (carpet and upholstery only) and 2, 4, and 8 weeks posttreatment. We compared pretreatment mean allergen concentrations and loads to posttreatment values and performed between-group analyses after adjusting for differences in the pretreatment means. Both dry steam cleaning plus vacuuming and vacuuming alone resulted in a significant reduction in carpet house dust mite allergen concentration and load (p < 0.05). Levels approached pretreatment values by 4 weeks posttreatment in the intensive vacuuming group, whereas steam cleaning plus vacuuming effected a decrease that persisted for up to 8 weeks. Significant decreases in bed house dust mite allergen concentration and load were obtained in response to encasement and either professional or in-home laundering (p < 0.001). Between-group analysis revealed significantly less postintervention house dust mite allergen load in professionally laundered compared to home-laundered beds (p < 0.05). Intensive vacuuming and dry

  2. Traffic signatures in suspended dust at pedestrian levels in semiarid zones: Implications for human exposure

    NASA Astrophysics Data System (ADS)

    Meza-Figueroa, Diana; González-Grijalva, Belem; Del Río-Salas, Rafael; Coimbra, Rute; Ochoa-Landin, Lucas; Moreno-Rodríguez, Verónica

    2016-08-01

    Deeper knowledge on dust suspension processes along semiarid zones is critical for understanding potential impacts on human health. Hermosillo city, located in the heart of the Sonoran Desert was chosen to evaluate such impacts. A one-year survey of Total Suspended Particulate Matter (TSPM) was conducted at two different heights (pedestrian and rooftop level). The minimum values of TSPM were reported during monsoon season and winter. Maximum values showed a bimodal distribution, with major peaks associated with increase and decrease of temperature, as well as decreasing humidity. Concentrations of TSPM were significantly exceeded at pedestrian level (∼44% of analyzed days) when compared to roof level (∼18% of analyzed days). Metal concentrations of As, Pb, Cu, Sb, Be, Mg, Ni, and Co were higher at pedestrian level than at roof level. Pixel counting and interpretations based on scanning electron microscopy of dust filters showed a higher percentage of fine particulate fractions at pedestrian level. These fractions occur mainly as metal-enriched agglomerates resembling coarser particles. According to worldwide guidelines, particulate matter sampling should be conducted by monitoring particle sizes equal and inferior to PM10. However, this work suggests that such procedures may compromise risk assessment in semiarid environments, where coarse particles act as main carriers for emergent contaminants related to traffic. This effect is especially concerning at pedestrian level, leading to an underestimation of potential impacts of human exposure. This study brings forward novel aspects that are of relevance for those concerned with dust suspension processes across semiarid regions and related impact on human health.

  3. Endotoxin and House Dust Mite Allergen Levels on Synthetic and Buckwheat Pillows

    PubMed Central

    Nam, Hae-Seon; Park, Choon-Sik; Crane, Julian

    2004-01-01

    Pillows are known to contain significant levels of indoor allergens and endotoxin, that are of importance to house dust mite sensitized asthmatics. Buckwheat pillows are commonly used in Korea. We studied the levels of the house dust mite allergen, Der f 1, and endotoxin on new synthetic and buckwheat pillows and their accumulation over three months. Endotoxin levels were significantly higher on new buckwheat pillows compared to synthetic pillows; geometric mean levels (95% CI) were 60,950 EU/g (30,270-122,700) and 4,887 EU/g (2,570-9,311) respectively (p<0.001). No Der f 1 was detected on the new pillows. After three months Der f 1 levels were similar on buckwheat and synthetic pillows, geometric mean levels (95% CI) were 1.16 µg/g (0.02-8.13) and 1.08 µg/g (0.19-1.68) respectively. These results indicate that buckwheat pillows are a source of very high endotoxin levels that may be of relevance to asthma severity of atopic asthmatics. PMID:15308838

  4. Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations

    NASA Astrophysics Data System (ADS)

    Ryder, C. L.; McQuaid, J. B.; Flamant, C.; Washington, R.; Brindley, H. E.; Highwood, E. J.; Marsham, J. H.; Parker, D. J.; Todd, M. C.; Banks, J. R.; Brooke, J. K.; Engelstaedter, S.; Estellés, V.; Formenti, P.; Garcia-Carreras, L.; Kocha, C.; Marenco, F.; Rosenberg, P.; Sodemann, H.; Allen, C. J. T.; Bourdon, A.; Bart, M.; Cavazos-Guerra, C.; Chevaillier, S.; Crosier, J.; Darbyshire, E.; Dean, A. R.; Dorsey, J. R.; Kent, J.; O'Sullivan, D.; Schepanski, K.; Szpek, K.; Woolley, A.

    2015-01-01

    The Fennec climate program aims to improve understanding of the Saharan climate system through a synergy of observations and modelling. We present a description of the Fennec airborne observations during 2011 and 2012 over the remote Sahara (Mauritania and Mali) and the advances in the understanding of mineral dust and boundary layer processes they have provided. Aircraft instrumentation aboard the UK FAAM BAe146 and French SAFIRE Falcon 20 is described, with specific focus on instrumentation specially developed and relevant to Saharan meteorology and dust. Flight locations, aims and associated meteorology are described. Examples and applications of aircraft measurements from the Fennec flights are presented, highlighting new scientific results delivered using a synergy of different instruments and aircraft. These include: (1) the first airborne measurement of dust particles sized up to 300 microns and associated dust fluxes in the Saharan atmospheric boundary layer (SABL), (2) dust uplift from the breakdown of the nocturnal low-level jet before becoming visible in SEVIRI satellite imagery, (3) vertical profiles of the unique vertical structure of turbulent fluxes in the SABL, (4) in-situ observations of processes in SABL clouds showing dust acting as CCN and IN at -15 °C, (5) dual-aircraft observations of the SABL dynamics, thermodynamics and composition in the Saharan heat low region (SHL), (6) airborne observations of a dust storm associated with a cold-pool (haboob) issued from deep convection over the Atlas, (7) the first airborne chemical composition measurements of dust in the SHL region with differing composition, sources (determined using Lagrangian backward trajectory calculations) and absorption properties between 2011 and 2012, (8) coincident ozone and dust surface area measurements suggest coarser particles provide a route for ozone depletion, (9) discrepancies between airborne coarse mode size distributions and AERONET sunphotometer retrievals under

  5. The contribution of lead-contaminated house dust and residential soil to children`s blood lead levels

    SciTech Connect

    Lanphear, B.P.; Matte, T.D.; Rogers, J.

    1998-10-01

    In 1992, the US Congress passed the Residential Lead-Based Paint Hazard Reduction Act, which requires the promulgation of health-based dust lead and soil lead standards for residential dwellings to prevent undue lead exposure in children. Unfortunately, the levels of lead in house dust and soil that are associated with elevated blood lead levels among US children remain poorly defined. This pooled analysis was done to estimate the contributions of lead-contaminated house dust and soil to children`s blood lead levels. The results of this pooled analysis, the most comprehensive existing epidemiologic analysis of childhood lead exposure, confirm that lead-contaminated house dust is the major source of lead exposure for children. These analyses further demonstrate that a strong relationship between interior dust lead loading and children`s blood lead levels persists at dust lead levels considerably below the US Department of Housing and urban Development`s current post-abatement standards and the Environmental Protection Agency`s guidance levels. Finally, these analyses demonstrate that a child`s age, race, mouthing behaviors, and study-site specific factors influence the predicted blood lead level at a given level of exposure. These data can be used to estimate the potential health impact of alternative health-based lead standards for residential sources of lead exposure.

  6. Monitoring of workers exposure to low levels of airborne monomers in a polystyrene production plant

    SciTech Connect

    Samimi, B.; Falbo, L.

    1982-11-01

    Exposure of workers to sub-ppm levels of airborne monomers, namely ethyl acrylate, methyl methacrylate, n-butyl acrylate, styrene, ..cap alpha..-methylstyrene, and 20 ethylhexyl acrylate, in a polystyrene production plant was measured in the same sample on a single gas chromatographic column. The best separation and sensitivity were obtained with a 3 m x 3.175 mm stainless steel column packed with 10% FFAP on Chromosorb and a temperature programmed from 70/sup 0/C to 110/sup 0/C. A total of 106 air samples were collected on 150 mg charcoal tubes from the breathing zone of workers, from areas near reactors, and from places where monomers were unloaded from trucks and tank cars. Samples were analyzed in a manner similar to the method recommended by NIOSH. The mean TWA concentrations in a worker's breathing zone were 89, 66, 49, 120, 41, 1 ppb for ethyl acrylate, methyl methacrylate, n-butyl acrylate, styrene, ..cap alpha..-methylstyrene, and 2-ethylhexyl acrylate, respectively. The highest TWA breathing zone concentration was 14.8 ppm for styrene, which occurred during unloading and sampling of the monomer for a quality check. The mean TWA concentration of monomers in the air of the workplace were 1.1 ppm, 169,36,54,10, and 30 ppb for the same 6 compounds mentioned above. The highest area TWA concentration was 57 ppm for ethyl acrylate, which occurred outdoors at the truck and tank car unloading site. It was concluded that use of two separate local exhaust ventilating systems in this polymerization process were effecive in maintaining negative pressure within the reactors under all circumstances of use. These engineering controls and care in handling monomers have resulted in a relatively safe working environment.

  7. Evaluation of longwall dust sources. Open file report 15 Sep 80-15 Apr 83

    SciTech Connect

    Ludlow, J.; Marshall, E.

    1983-04-01

    The major objective of this study was to define the relative contributions of various sources of respirable airborne dust on longwall faces. In order to define the contribution of various primary sources, continuous dust level data were recorded on five longwalls for an average of five shifts at each. By analysis of these data with records of face activity, it was possible to determine the overall contribution of each of the major elements of the longwall system to overall respirable dust exposure at various face locations. Average levels were determined for roof support generated dust, conveyor and intake dust, and for dust levels during various shearer activities. When average levels are compared between mines, a significant degree of consistency is noted. Another objective of the study was to differentiate the various dust sources associated with the shearer.

  8. Relationship between levels of very virulent MDV in poultry dust and in feather tips from vaccinated chickens.

    PubMed

    Baigent, Susan J; Kgosana, Lydia B; Gamawa, Ahmed A; Smith, Lorraine P; Read, Andrew F; Nair, Venugopal K

    2013-06-01

    To assess the effect of various vaccine strains on replication and shedding of virulent Marek's disease virus from experimentally infected chickens, quantitative PCR (q-PCR) methods were developed to accurately quantify viral DNA in infected chickens and in the environment in which they were housed. Four groups of 10 chickens, kept in poultry isolators, were vaccinated at 1 day old with one of four vaccines covering each of the three vaccine serotypes, then challenged with very virulent MDV strain Md5 at 8 days of age. At regular time-points, feather tips were collected from each chicken and poultry dust was collected from the air-extract prefilter of each isolator. DNA was extracted from feather and dust samples and subjected to real-time q-PCR, targeting the U(S)2 gene of MDV-1, in order to measure Md5 level per 10(4) feather tip cells or per microgram of dust. Accuracy of DNA extraction from dust and real-time q-PCR were validated by comparing either q-PCR cycle threshold values or the calculated MDV genome level; for use in q-PCR, DNA was extracted from serial dilutions of MDV-infected dust diluted with noninfected dust, or DNA from MDV-infected dust was diluted with DNA from noninfected dust. The results confirmed the accuracy and sensitivity of dust DNA extraction and subsequent q-PCR and showed that differences in virus levels between dust samples truly reflect differences in shedding. Vaccination delayed both replication of Md5 in feather tips and shedding of Md5. First detection of Md5 in feather tips always preceded or coincided with first detection in dust in each group. pCVI988 and HVT+SB-1 were the most efficient vaccines in reducing both replication and shedding of Md5. There was close correlation between mean virus level in feathers of each group and mean virus level in the dust shed by that group. This relationship was similar in each of the vaccinated groups, demonstrating that measurement of the virus in dust can be used to monitor accurately both

  9. Contribution of the Middle Eastern dust source areas to PM10 levels in urban receptors: Case study of Tehran, Iran

    NASA Astrophysics Data System (ADS)

    Givehchi, Raheleh; Arhami, Mohammad; Tajrishy, Massoud

    2013-08-01

    The origins and evolution of the Middle Eastern dust storms which frequently impact the residents of this arid region were studied. A methodology was adapted and developed to identify the desert regions of potential dust sources and determine their contributions to PM10 concentrations in the highly-populated receptor city of Tehran, Iran. Initially, the episodes of regional dust intrusion and the resulting amounts of increase in the particulate concentrations during these episodes were determined using a statistical analyzing methodology. The dust episodes were also inspected with the aerosol index information from the Ozone Monitoring Instrument (OMI). The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used as the main tool to determine the proportions of dust originating from different deserts during the dusty episodes of 2009-2010. Daily 5-day back trajectories were obtained from the receptor stations during the dust outbreaks in order to find and confirm the location of potential sources. After the boundaries of the potential sources were determined by 5-day backward trajectories, this region was divided into different areas to quantify their contributions to the measured PM10 levels. The proximity between the measured and simulated data confirmed the ability of HYSPLIT in modeling the Middle Eastern dust intrusion and estimating the particulate concentration in the downwind receptor sites. Results showed that the deserts in Iraq and Syria are the main contributing dust sources which comprise more than 90% of the dust related PM10 concentrations in Tehran, during the studied dust episodes. The sources in northern Iraq and eastern Syria respectively represented 44% and 32% contributions on average.

  10. Characterization of dust emission from alluvial sediments using aircraft observations and modeling

    NASA Astrophysics Data System (ADS)

    Schepanski, K.; Flamant, C.; Chaboureau, J.; Kocha, C.; Banks, J.; Brindley, H. E.; Lavaysse, C.; Marnas, F.; Pelon, J.; Tulet, P.

    2013-12-01

    Recent studies using satellite observations show that numerous dust sources are located in the foothills of arid and semi-arid mountain regions such as over North Africa. Alluvial sediments deposited on the valley bottoms and flood plains are very prone to wind erosion and frequently serve as dust source. High surface wind speeds related to the break-down of the nocturnal low-level jet (LLJ) during the morning hours are identified as a frequent driving mechanism for dust uplift. We investigate dust emission from alluvial dust sources located within the upland region in northern Mauritania and discuss the impact of valleys with regard to their role as dust source. Measures for local atmospheric dust burden were retrieved from airborne observations, MSG SEVIR dust AOD fields and MesoNH model simulations, and analyzed in order to provide complementary information on dust source activation and local dust transport at different horizontal scales. Vertical distribution of atmospheric mineral dust was obtained from the LNG backscatter lidar system flying aboard the French Falcon-20 aircraft. Lidar extinction coefficients were compared to topography, aerial photographs, and dust AOD fields to confirm the relevance of alluvial sediments at the valley bottoms as dust source. The observed dust emission event was further evaluated using the regional model MesoNH. A sensitivity study on the impact of the horizontal grid spacing highlights the importance of the spatial resolution on simulated dust loadings. The results further illustrate the importance of an explicit representation of alluvial dust sources in such models to better capture the spatial-temporal distribution of airborne dust concentrations.

  11. Correlation between predicted and observed levels of airborne tritium at Lawrence Livermore Laboratory site boundary

    SciTech Connect

    Lindeken, C.L.; Silver, W.J.; Toy, A.J.; White, J.H.

    1980-02-19

    At the Lawrence Livermore Laboratory, a computer code based on the Gaussian plume model is used to estimate radiation doses from routine or accidental release of airborne radioactive material. Routine releases of tritium have been used as a test of the overall uncertainty associated with these estimates. The ration of concentration to release rate at distances from the two principal release points to each of six site boundary sampling locations has been calcuated using local meteorological data. The concentration of airborne tritiated water vapor is continuously measured at the six sampling stations as part of the Laboratory's environmental monitoring program. Comparison of predicted with observed annual tritiated water concentrations in 1978 showed an average ratio of 2.6 with a range of from 0.97 to 5.8.

  12. Levels of phthalate esters in settled house dust from urban dwellings with young children in Nanjing, China

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Lu, Xiao-Mei; Zhang, Xiao-Ling; Sun, Yong-Gang; Zhu, Dong-Mei; Wang, Bing-Ling; Zhao, Ren-Zheng; Zhang, Zheng-Dong

    2013-04-01

    To investigate the levels and possible determinants of phthalate esters (PEs) in settled house dust from urban dwellings with young children, dust was collected from 215 urban houses in Nanjing, China, and 145 outdoor settled dust samples were collected nearby. Six PEs were measured by gas chromatography/mass spectrometry. All PEs were detected in the dust from approximately 90% of the houses, with the exception of dioctyl phthalate (DOP), which had only a 59% detection rate. Di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP) were the most abundant PEs, with geometric means of 110 and 16.4 μg g-1, respectively, and maximal concentrations 9950 and 2150 μg g-1. Factor analysis showed that DBP, DEHP and benzyl butyl phthalate (BBP) might come from the same source and were significantly influenced by the use of solid-wood floor wax. High BBP, DEHP, DOP and total PE levels were associated with indices of dampness, and high DOP was associated with humidifier use. In conclusion, six PEs are ubiquitous in urban settled house dust in Nanjing, China, and both plastic materials and cosmetic and personal care products are important sources. Flooring material, dampness and humidifier use potentially influence house dust PE levels.

  13. Correlation between airborne Olea europaea pollen concentrations and levels of the major allergen Ole e 1 in Córdoba, Spain, 2012-2014

    NASA Astrophysics Data System (ADS)

    Plaza, M. P.; Alcázar, P.; Galán, C.

    2016-04-01

    Olea europaea L. pollen is the second-largest cause of pollinosis in the southern Iberian Peninsula. Airborne-pollen monitoring networks provide essential data on pollen dynamics over a given study area. Recent research, however, has shown that airborne pollen levels alone do not always provide a clear indicator of actual exposure to aeroallergens. This study sought to evaluate correlations between airborne concentrations of olive pollen and Ole e 1 allergen levels in Córdoba (southern Spain), in order to determine whether atmospheric pollen concentrations alone are sufficient to chart changes in hay fever symptoms. The influence of major weather-related variables on local airborne pollen and allergen levels was also examined. Monitoring was carried out from 2012 to 2014. Pollen sampling was performed using a Hirst-type sampler, following the protocol recommended by the Spanish Aerobiology Network. A multi-vial cyclone sampler was used to collect aeroallergens, and allergenic particles were quantified by ELISA assay. Significant positive correlations were found between daily airborne allergen levels and atmospheric pollen concentrations, although there were occasions when allergen was detected before and after the pollen season and in the absence of airborne pollen. The correlation between the two was irregular, and pollen potency displayed year-on-year variations and did not necessarily match pollen-season-intensity.

  14. House Dust Concentrations of Organophosphate Flame Retardants in Relation to Hormone Levels and Semen Quality Parameters

    PubMed Central

    Meeker, John D.; Stapleton, Heather M.

    2010-01-01

    Background Organophosphate (OP) compounds, such as tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate (TPP), are commonly used as additive flame retardants and plasticizers in a wide range of materials. Although widespread human exposure to OP flame retardants is likely, there is a lack of human and animal data on potential health effects. Objective We explored relationships of TDCPP and TPP concentrations in house dust with hormone levels and semen quality parameters. Methods We analyzed house dust from 50 men recruited through a U.S. infertility clinic for TDCPP and TPP. Relationships with reproductive and thyroid hormone levels, as well as semen quality parameters, were assessed using crude and multivariable linear regression. Results TDCPP and TPP were detected in 96% and 98% of samples, respectively, with widely varying concentrations up to 1.8 mg/g. In models adjusted for age and body mass index, an interquartile range (IQR) increase in TDCPP was associated with a 3% [95% confidence interval (CI), −5% to −1%) decline in free thyroxine and a 17% (95% CI, 4–32%) increase in prolactin. There was a suggestive inverse association between TDCPP and free androgen index that became less evident in adjusted models. In the adjusted models, an IQR increase in TPP was associated with a 10% (95% CI, 2–19%) increase in prolactin and a 19% (95% CI, −30% to −5%) decrease in sperm concentration. Conclusion OP flame retardants may be associated with altered hormone levels and decreased semen quality in men. More research on sources and levels of human exposure to OP flame retardants and associated health outcomes are needed. PMID:20194068

  15. EXOZODIACAL DUST LEVELS FOR NEARBY MAIN-SEQUENCE STARS: A SURVEY WITH THE KECK INTERFEROMETER NULLER

    SciTech Connect

    Millan-Gabet, R.; Serabyn, E.; Mennesson, B.; Traub, W. A.; Stapelfeldt, K.; Bryden, G.; Colavita, M. M.; Booth, A. J.; Barry, R. K.; Danchi, W. C.; Kuchner, M.; Stark, C. C.; Ragland, S.; Hrynevych, M.; Woillez, J.

    2011-06-10

    The Keck Interferometer Nuller (KIN) was used to survey 25 nearby main-sequence stars in the mid-infrared, in order to assess the prevalence of warm circumstellar (exozodiacal) dust around nearby solar-type stars. The KIN measures circumstellar emission by spatially blocking the star but transmitting the circumstellar flux in a region typically 0.1-4 AU from the star. We find one significant detection ({eta} Crv), two marginal detections ({gamma} Oph and {alpha} Aql), and 22 clear non-detections. Using a model of our own solar system's zodiacal cloud, scaled to the luminosity of each target star, we estimate the equivalent number of target zodis needed to match our observations. Our three zodi detections are {eta} Crv (1250 {+-} 260), {gamma} Oph (200 {+-} 80), and {alpha} Aql (600 {+-} 200), where the uncertainties are 1{sigma}. The 22 non-detected targets have an ensemble weighted average consistent with zero, with an average individual uncertainty of 160 zodis (1{sigma}). These measurements represent the best limits to date on exozodi levels for a sample of nearby main-sequence stars. A statistical analysis of the population of 23 stars not previously known to contain circumstellar dust (excluding {eta} Crv and {gamma} Oph) suggests that, if the measurement errors are uncorrelated (for which we provide evidence) and if these 23 stars are representative of a single class with respect to the level of exozodi brightness, the mean exozodi level for the class is <150 zodis (3{sigma} upper limit, corresponding to 99% confidence under the additional assumption that the measurement errors are Gaussian). We also demonstrate that this conclusion is largely independent of the shape and mean level of the (unknown) true underlying exozodi distribution.

  16. Elevated levels of perfluoroalkyl acids in family members of occupationally exposed workers: the importance of dust transfer

    NASA Astrophysics Data System (ADS)

    Fu, Jianjie; Gao, Yan; Wang, Thanh; Liang, Yong; Zhang, Aiqian; Wang, Yawei; Jiang, Guibin

    2015-03-01

    The exposure pathways of perfluoroalkyl acids (PFAAs) to humans are still not clear because of the complex living environment, and few studies have simultaneously investigated the bioaccumulative behaviour of different PFAAs in humans. In this study, serum, dust, duplicate diet, and other matrices were collected around a manufacturing plant in China, and homologous series of PFAAs were analysed. PFAA levels in dust and serum of local residents in this area were considerably higher than those in non-polluted area. Although dietary intake was the major exposure pathway in the present study, dust ingestion played an important role in this case. Serum PFAAs in local residents was significantly correlated with dust PFAAs levels in their living or working microenvironment. Serum PFAAs and dust PFAAs were significantly higher in family members of occupational workers (FM) than in ordinary residents (OR) (p < 0.01). After a careful analysis of the PFAAs exposure pathway, a potential pathway in addition to direct dust ingestion was suggested: PFAAs might transferred from occupational worker's clothes to dinners via cooking processes. The bioaccumulative potential of PFHxS and PFOS were higher than other PFAAs, which suggested a substantial difference between the bioaccumulative ability of perfluorinated sulfonic acids and perfluorinated carboxylic acids.

  17. Column Closure Studies of Lower Tropospheric Aerosol and Water Vapor During ACE-Asia Using Airborne Sunphotometer, Airborne In-Situ and Ship-Based Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Hegg, A.; Wang, J.; Bates, D.; Redemann, J.; Russells, P. B.; Livingston, J. M.; Jonsson, H. H.; Welton, E. J.; Seinfield, J. H.

    2003-01-01

    We assess the consistency (closure) between solar beam attenuation by aerosols and water vapor measured by airborne sunphotometry and derived from airborne in-situ, and ship-based lidar measurements during the April 2001 Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The airborne data presented here were obtained aboard the Twin Otter aircraft. Comparing aerosol extinction o(550 nm) from four different techniques shows good agreement for the vertical distribution of aerosol layers. However, the level of agreement in absolute magnitude of the derived aerosol extinction varied among the aerosol layers sampled. The sigma(550 nm) computed from airborne in-situ size distribution and composition measurements shows good agreement with airborne sunphotometry in the marine boundary layer but is considerably lower in layers dominated by dust if the particles are assumed to be spherical. The sigma(550 nm) from airborne in-situ scattering and absorption measurements are about approx. 13% lower than those obtained from airborne sunphotometry during 14 vertical profiles. Combining lidar and the airborne sunphotometer measurements reveals the prevalence of dust layers at altitudes up to 10 km with layer aerosol optical depth (from 3.5 to 10 km altitude) of approx. 0.1 to 0.2 (500 nm) and extinction-to-backscatter ratios of 59-71 sr (523 nm). The airborne sunphotometer aboard the Twin Otter reveals a relatively dry atmosphere during ACE- Asia with all water vapor columns less than 1.5 cm and water vapor densities w less than 12 g/cu m. Comparing layer water vapor amounts and w from the airborne sunphotometer to the same quantities measured with aircraft in-situ sensors leads to a high correlation (r(sup 3)=0.96) but the sunphotometer tends to underestimate w by 7%.

  18. Application of infrared radiometers for airborne detection of clear air turbulence and low level wind shear, airborne infrared low level wind shear detection test

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.

    1985-01-01

    The feasibility of infrared optical techniques for the advance detection and avoidance of low level wind shear (LLWS) or low altitude wind shear hazardous to aircraft operations was investigated. A primary feasibility research effort was conducted with infrared detectors and instrumentation aboard the NASA Ames Research Center Learjet. The main field effort was flown on the NASA-Ames Dryden B57B aircraft. The original approach visualized a forward-looking, infrared transmitting (KRS-5) window through which signals would reach the detector. The present concept of a one inch diameter light pipe with a 45 deg angled mirror enables a much simpler installation virtually anywhere on the aircraft coupled with the possibility of horizontal scanning via rotation of the forward directed mirror. Present infrared detectors and filters would certainly permit ranging and horizontal scanning in a variety of methods. CRT display technology could provide a contoured picture with possible shear intensity levels from the infrared detection system on the weather radar or a small adjunct display. This procedure shoud be further developed and pilot evaluated in a light aircraft such as a Cessna 207 or equivalent.

  19. Airborne and surface-level in situ observations of wintertime clouds in the Southern Rockies

    NASA Astrophysics Data System (ADS)

    Dorsi, Samuel Winchester

    The phase of cloud water has important impacts on cloud radiative properties, cloud lifetime, and the formation of precipitation. Mixed-phase clouds, or those in which liquid droplets, ice particle and water vapor co-exist, are of particular importance in the Southern Rockies of the United States, where these clouds enhance wintertime mountain precipitation mass and annual water storage in the snowpack. The interaction between multiple water phases within a cloud presents challenges for in situ observation. I describe the existing in situ cloud microphysical instrumentation, and introduce a new instrument for the in situ measurement of total water concentration: the second-generation University of Colorado closed-path tunable-diode laser hygrometer (CLH-2). This compact instrument can be flown within a scientific aircraft under-wing canister and is designed for operation in diverse environmental conditions. During the winter 2010-2011, the CLH-2 was installed on a wind vane at Storm Peak Laboratory (SPL) in the Park Range of Colorado as a part of the Storm Peak Laboratory Cloud Property Validation Experiment (StormVEx) campaign. I apply a new method for determining the bulk mass-dimensional relationship of ice particles from ground-based observations. Despite important difference between airborne and ground-based particle measurements, my parameterization yields particle masses close to those from recent airborne studies that take into account the effect of ice particle shattering on observed number concentrations. Variations in particle density over the course of a storm are suggested by time variations between the observed and parameterized ice water concentrations. Using observations from the Wyoming King Air research aircraft collected during the Colorado Airborne Multi-Phase Cloud Study (CAMPS) in winter 2010-2011, cloud water phase is identified using in situ microphysical measurements. While mixed-phase clouds are identified throughout the study area, the

  20. Levels and spatial distribution of airborne chemical elements in a heavy industrial area located in the north of Spain.

    PubMed

    Lage, J; Almeida, S M; Reis, M A; Chaves, P C; Ribeiro, T; Garcia, S; Faria, J P; Fernández, B G; Wolterbeek, H T

    2014-01-01

    The adverse health effects of airborne particles have been subjected to intense investigation in recent years; however, more studies on the chemical characterization of particles from pollution emissions are needed to (1) identify emission sources, (2) better understand the relative toxicity of particles, and (3) pinpoint more targeted emission control strategies and regulations. The main objective of this study was to assess the levels and spatial distribution of airborne chemical elements in a heavy industrial area located in the north of Spain. Instrumental and biomonitoring techniques were integrated and analytical methods for k0 instrumental neutron activation analysis and particle-induced x-ray emission were used to determine element content in aerosol filters and lichens. Results indicated that in general local industry contributed to the emissions of As, Sb, Cu, V, and Ni, which are associated with combustion processes. In addition, the steelwork emitted significant quantities of Fe and Mn and the cement factory was associated with Ca emissions. The spatial distribution of Zn and Al also indicated an important contribution of two industries located outside the studied area. PMID:25072718

  1. Taklimakan Desert nocturnal low-level jet: climatology and dust activity

    NASA Astrophysics Data System (ADS)

    Ge, Jin Ming; Liu, Huayue; Huang, Jianping; Fu, Qiang

    2016-06-01

    While nocturnal low-level jets (NLLJs) occur frequently in many parts of the world, the occurrence and other detailed characteristics of NLLJs over the Taklimakan Desert (TD) are not well known. This paper presents a climatology of NLLJs and coincident dust over the TD by analyzing multi-year ERA-Interim reanalysis and satellite observations. It is found that the ERA-Interim dataset can capture the NLLJs' features well by comparison with radiosonde data from two surface sites. The NLLJs occur in more than 60 % of nights, which are primarily easterly to east-northeasterly. They typically appear at 100 to 400 m above the surface with a speed of 4 to 10 m s-1. Most NLLJs are located above the nocturnal inversion during the warm season, while they are embedded in the inversion layer during the cold season. NLLJs above the inversion have a strong annual cycle with a maximum frequency in August. We also quantify the convective boundary layer (CBL) height and construct an index to measure the magnitude of the momentum in the CBL. We find that the magnitude of momentum in the lower atmosphere from the top of the surface layer to the top of mixed layer is larger for NLLJ cases than for non-NLLJ cases, and in the warm season the downward momentum transfer process is more intense and rapid. The winds below the NLLJ core to the desert surface gain strength in summer and autumn, and these summer and autumn winds are coincident with an enhancement of aerosol optical depth. This indicates that the NLLJ is an important mechanism for dust activity and transport during the warm season over the Taklimakan.

  2. Pneumoconiosis, lung function and exposure to airborne dust: epidemiological research to compare responses of working coalminers with responses of ex-miners. Part 2. Final report

    SciTech Connect

    Soutar, C.A.; Maclaren, W.; Hurley, F.; Murdoch, R.; Hadden, G.

    1982-03-01

    The relationship between dust exposure and disease for miners was compared with that for ex-miners, in order to determine whether relationships found in other studies on miners alone could be applied to both groups. 17,738 men examined in the 1950s were followed up approximately 22 years later. Sixty one per cent of the survivors were examined, being 40% of the original sample. Records were made of respiratory symptoms, smoking habit, lung spirometry and chest radiograph findings. Radiographs were interpreted according to the International Labour Office Classification of Pneumoconiosis. Lifetime dust exposure was calculated for each subject. The dust/disease relationship was found to be the same for both groups. Ex-miners were found to have more pneumoconiosis and fibrosis and to be in worse health than miners. Pneumoconiosis progression was shown to be related to continued dust exposure; fibrosis progression was related to the presence of dust in the lungs. Dust exposure was shown to cause a mainly restrictive pattern of lung disease in contrast to the obstructive pattern caused by smoking. Colliery-related differences were found in lung disease which it was felt needed further investigation.

  3. Climatology of nocturnal low-level jets over North Africa and implications for modeling mineral dust emission

    PubMed Central

    Fiedler, S; Schepanski, K; Heinold, B; Knippertz, P; Tegen, I

    2013-01-01

    [1] This study presents the first climatology for the dust emission amount associated with Nocturnal Low-Level Jets (NLLJs) in North Africa. These wind speed maxima near the top of the nocturnal boundary layer can generate near-surface peak winds due to shear-driven turbulence in the course of the night and the NLLJ breakdown during the following morning. The associated increase in the near-surface wind speed is a driver for mineral dust emission. A new detection algorithm for NLLJs is presented and used for a statistical assessment of NLLJs in 32 years of ERA-Interim reanalysis from the European Centre for Medium-Range Weather Forecasts. NLLJs occur in 29% of the nights in the annual and spatial mean. The NLLJ climatology shows a distinct annual cycle with marked regional differences. Maxima of up to 80% NLLJ frequency are found where low-level baroclinicity and orographic channels cause favorable conditions, e.g., over the Bodélé Depression, Chad, for November–February and along the West Saharan and Mauritanian coast for April–September. Downward mixing of NLLJ momentum to the surface causes 15% of mineral dust emission in the annual and spatial mean and can be associated with up to 60% of the total dust amount in specific areas, e.g., the Bodélé Depression and south of the Hoggar-Tibesti Channel. The sharp diurnal cycle underlines the importance of using wind speed information with high temporal resolution as driving fields for dust emission models. Citation: Fiedler, S., K. Schepanski, B. Heinold, P. Knippertz, and I. Tegen (2013), Climatology of nocturnal low-level jets over North Africa and implications for modeling mineral dust emission, J. Geophys. Res. Atmos., 118, 6100-6121, doi:10.1002/jgrd.50394 PMID:25893154

  4. Surface dust wipes are the best predictors of blood leads in young children with elevated blood lead levels

    SciTech Connect

    Gulson, Brian; Anderson, Phil; Taylor, Alan

    2013-10-15

    Background: As part of the only national survey of lead in Australian children, which was undertaken in 1996, lead isotopic and lead concentration measurements were obtained from children from 24 dwellings whose blood lead levels were ≥15 µg/dL in an attempt to determine the source(s) of their elevated blood lead. Comparisons were made with data for six children with lower blood lead levels (<10 µg/dL). Methods: Thermal ionisation and isotope dilution mass spectrometry were used to determine high precision lead isotopic ratios ({sup 208}Pb/{sup 206}Pb, {sup 207}Pb/{sup 206}Pb and {sup 206}Pb/{sup 204}Pb) and lead concentrations in blood, dust from floor wipes, soil, drinking water and paint (where available). Evaluation of associations between blood and the environmental samples was based on the analysis of individual cases, and Pearson correlations and multiple regression analyses based on the whole dataset. Results and discussion: The correlations showed an association for isotopic ratios in blood and wipes (r=0.52, 95% CI 0.19–0.74), blood and soil (r=0.33, 95% CI −0.05–0.62), and blood and paint (r=0.56, 95% CI 0.09–0.83). The regression analyses indicated that the only statistically significant relationship for blood isotopic ratios was with dust wipes (B=0.65, 95% CI 0.35–0.95); there were no significant associations for lead concentrations in blood and environmental samples. There is a strong isotopic correlation of soils and house dust (r=0.53, 95% CI 0.20–0.75) indicative of a common source(s) for lead in soil and house dust. In contrast, as with the regression analyses, no such association is present for bulk lead concentrations (r=−0.003, 95% CI −0.37–0.36), the most common approach employed in source investigations. In evaluation of the isotopic results on a case by case basis, the strongest associations were for dust wipes and blood. -- Highlights: • Children with elevated blood lead ≥15 µg/dL compared with a group with <10

  5. Uranium mill ore dust characterization

    SciTech Connect

    Knuth, R.H.; George, A.C.

    1980-11-01

    Cascade impactor and general air ore dust measurements were taken in a uranium processing mill in order to characterize the airborne activity, the degree of equilibrium, the particle size distribution and the respirable fraction for the /sup 238/U chain nuclides. The sampling locations were selected to limit the possibility of cross contamination by airborne dusts originating in different process areas of the mill. The reliability of the modified impactor and measurement techniques was ascertained by duplicate sampling. The results reveal no significant deviation from secular equilibrium in both airborne and bulk ore samples for the /sup 234/U and /sup 230/Th nuclides. In total airborne dust measurements, the /sup 226/Ra and /sup 210/Pb nuclides were found to be depleted by 20 and 25%, respectively. Bulk ore samples showed depletions of 10% for the /sup 226/Ra and /sup 210/Pb nuclides. Impactor samples show disequilibrium of /sup 226/Ra as high as +-50% for different size fractions. In these samples the /sup 226/Ra ratio was generally found to increase as particle size decreased. Activity median aerodynamic diameters of the airborne dusts ranged from 5 to 30 ..mu..m with a median diameter of 11 ..mu..m. The maximum respirable fraction for the ore dusts, based on the proposed International Commission on Radiological Protection's (ICRP) definition of pulmonary deposition, was < 15% of the total airborne concentration. Ore dust parameters calculated for impactor duplicate samples were found to be in excellent agreement.

  6. MM wave SAR sensor design: Concept for an airborne low level reconnaissance system

    NASA Astrophysics Data System (ADS)

    Boesswetter, C.

    1986-07-01

    The basic system design considerations for a high resolution SAR system operating at 35 GHz or 94 GHz are given. First it is shown that only the focussed SAR concept in the side looking configuration matches the requirements and constraints. After definition of illumination geometry and airborne modes the fundamental SAR parameters in range and azimuth direction are derived. A review of the performance parameters of some critical mm wave components (coherent pulsed transmitters, front ends, antennas) establish the basis for further analysis. The power and contrast budget in the processed SAR image shows the feasibility of a 35/94 GHz SAR sensor design. The discussion of the resulting system parameters points out that this unusual system design implies both benefits and new risk areas. One of the benefits besides the compactness of sensor hardware turns out to be the short synthetic aperture length simplifying the design of the digital SAR processor, preferably operating in real time. A possible architecture based on current state-of-the-art correlator hardware is shown. One of the potential risk areas in achieving high resolution SAR imagery in the mm wave frequency band is motion compensation. However, it is shown that the short range and short synthetic aperture lengths ease the problem so that correction of motion induced phase errors and thus focussed synthetic aperture processing should be possible.

  7. [Chemical characteristics in airborne particulate matter (PM10) during a high pollution spring dust storm episode in Beijing, Tianjin and Zhangjiakou, China].

    PubMed

    Liu, Qing-Yang; Liu, Yan-Ju; Zhao, Qiang; Zhang, Ting-Ting; Zhang, Mei-Gen; Wang, Cun-Mei

    2014-08-01

    Atmospheric particulate matter (PM10) was collected at sampling locations of Beijing, Tianjin and Zhangjiakou from April 1st to May 24th, 2012. The mass concentration of PM10 and concentrations of ions, elemental carbon (EC) and organic carbon (OC) in PM10 were determined. The results showed that average mass concentration of PM10 were 233.82 microg x m(-3) for Beijing, 279.64 microg x (-3) for Tianjin and 238.13 microg x m(-3) for Zhangjiakou, respectively. Backward trajectories results confirmed dust storm events occurred from 27th to 29th April. The maximum daily mass concentrations of PM10 were 755.54 microg x m(-3) for Beijing, 831.32 microg x m(-3) for Tianjin and 582.82 microg x m(-3) for Zhangjiakou during the dust storm episodes, respectively. Water-soluble ions (Na+, NH4+, Ca2+, K+, F-, Cl-, NO3-, SO4(2-)), organic carbon (OC) and elemental carbon (EC) were major aerosol components during the dust storm episodes, and their concentrations were higher than non-dust storm days. In addition, dust storm caused increases in NO3-, SO4(2-) and enrichment of secondary organic carbon (SOC) concentration relative to OC, suggesting that chemical reaction processes involving gas-particle conversion occurred during the long-distance transport of aerosol particles. PMID:25338350

  8. Asthma, Airway Symptoms and Rhinitis in Office Workers in Malaysia: Associations with House Dust Mite (HDM) Allergy, Cat Allergy and Levels of House Dust Mite Allergens in Office Dust

    PubMed Central

    Lim, Fang Lee; Hashim, Zailina; Than, Leslie Thian Lung; Md Said, Salmiah; Hisham Hashim, Jamal; Norbäck, Dan

    2015-01-01

    A prevalence study was conducted among office workers in Malaysia (N= 695). The aim of this study was to examine associations between asthma, airway symptoms, rhinitis and house dust mites (HDM) and cat allergy and HDM levels in office dust. Medical data was collected by a questionnaire. Skin prick tests were performed for HDM allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae) and cat allergen Felis domesticus. Indoor temperature and relative air humidity (RH) were measured in the offices and vacuumed dust samples were analyzed for HDM allergens. The prevalence of D. pteronyssinus, D. farinae and cat allergy were 50.3%, 49.0% and 25.5% respectively. Totally 9.6% had doctor-diagnosed asthma, 15.5% had current wheeze and 53.0% had current rhinitis. The Der p 1 (from D. pteronyssinus) and Der f 1 (from D. farinae) allergens levels in dust were 556 ng/g and 658 ng/g respectively. Statistical analysis was conducted by multilevel logistic regression, adjusting for age, gender, current smoking, HDM or cat allergy, home dampness and recent indoor painting at home. Office workers with HDM allergy had more wheeze (p= 0.035), any airway symptoms (p= 0.032), doctor-diagnosed asthma (p= 0.005), current asthma (p= 0.007), current rhinitis (p= 0.021) and rhinoconjuctivitis (p< 0.001). Cat allergy was associated with wheeze (p= 0.021), wheeze when not having a cold (p= 0.033), any airway symptoms (p= 0.034), doctor-diagnosed asthma (p= 0.010), current asthma (p= 0.020) and nasal allergy medication (p= 0.042). Der f 1 level in dust was associated with daytime breathlessness (p= 0.033) especially among those with HDM allergy. Der f 1 levels were correlated with indoor temperature (p< 0.001) and inversely correlated with RH (p< 0.001). In conclusion, HDM and cat allergies were common and independently associated with asthma, airway symptoms and rhinitis. Der f 1 allergen can be a risk factor for daytime breathlessness. PMID:25923543

  9. Particle size distribution and perchlorate levels in settled dust from urban roads, parks, and roofs in Chengdu, China.

    PubMed

    Li, Yiwen; Shen, Yang; Pi, Lu; Hu, Wenli; Chen, Mengqin; Luo, Yan; Li, Zhi; Su, Shijun; Ding, Sanglan; Gan, Zhiwei

    2016-01-01

    A total of 27 settled dust samples were collected from urban roads, parks, and roofs in Chengdu, China to investigate particle size distribution and perchlorate levels in different size fractions. Briefly, fine particle size fractions (<250 μm) were the dominant composition in the settled dust samples, with mean percentages of 80.2%, 69.5%, and 77.2% for the urban roads, roofs, and the parks, respectively. Perchlorate was detected in all of the size-fractionated dust samples, with concentrations ranging from 73.0 to 6160 ng g(-1), and the median perchlorate levels increased with decreasing particle size. The perchlorate level in the finest fraction (<63 μm) was significantly higher than those in the coarser fractions. To our knowledge, this is the first report on perchlorate concentrations in different particle size fractions. The calculated perchlorate loadings revealed that perchlorate was mainly associated with finer particles (<125 μm). An exposure assessment indicated that exposure to perchlorate via settled road dust intake is safe to both children and adults in Chengdu, China. However, due to perchlorate mainly existing in fine particles, there is a potential for perchlorate to transfer into surface water and the atmosphere by runoff and wind erosion or traffic emission, and this could act as an important perchlorate pollution source for the indoor environment, and merits further study. PMID:26608047

  10. Solutions for extracting file level spatial metadata from airborne mission data

    NASA Astrophysics Data System (ADS)

    Schwab, M. J.; Stanley, M.; Pals, J.; Brodzik, M.; Fowler, C.; Icebridge Engineering/Spatial Metadata

    2011-12-01

    Authors: Michael Stanley Mark Schwab Jon Pals Mary J. Brodzik Cathy Fowler Collaboration: Raytheon EED and NSIDC Raytheon / EED 5700 Rivertech Court Riverdale, MD 20737 NSIDC University of Colorado UCB 449 Boulder, CO 80309-0449 Data sets acquired from satellites and aircraft may differ in many ways. We will focus on the differences in spatial coverage between the two platforms. Satellite data sets over a given period typically cover large geographic regions. These data are collected in a consistent, predictable and well understood manner due to the uniformity of satellite orbits. Since satellite data collection paths are typically smooth and uniform the data from satellite instruments can usually be described with simple spatial metadata. Subsequently, these spatial metadata can be stored and searched easily and efficiently. Conversely, aircraft have significantly more freedom to change paths, circle, overlap, and vary altitude all of which add complexity to the spatial metadata. Aircraft are also subject to wind and other elements that result in even more complicated and unpredictable spatial coverage areas. This unpredictability and complexity makes it more difficult to extract usable spatial metadata from data sets collected on aircraft missions. It is not feasible to use all of the location data from aircraft mission data sets for use as spatial metadata. The number of data points in typical data sets poses serious performance problems for spatial searching. In order to provide efficient spatial searching of the large number of files cataloged in our systems, we need to extract approximate spatial descriptions as geo-polygons from a small number of vertices (fewer than two hundred). We present some of the challenges and solutions for creating airborne mission-derived spatial metadata. We are implementing these methods to create the spatial metadata for insertion of IceBridge mission data into ECS for public access through NSIDC and ECHO but, they are

  11. Tropical forest structure characterization using airborne lidar data: an individual tree level approach

    NASA Astrophysics Data System (ADS)

    Ferraz, A.; Saatchi, S. S.

    2015-12-01

    Fine scale tropical forest structure characterization has been performed by means of field measurements techniques that record both the specie and the diameter at the breast height (dbh) for every tree within a given area. Due to dense and complex vegetation, additional important ecological variables (e.g. the tree height and crown size) are usually not measured because they are hardly recognized from the ground. The poor knowledge on the 3D tropical forest structure has been a major limitation for the understanding of different ecological issues such as the spatial distribution of carbon stocks, regeneration and competition dynamics and light penetration gradient assessments. Airborne laser scanning (ALS) is an active remote sensing technique that provides georeferenced distance measurements between the aircraft and the surface. It provides an unstructured 3D point cloud that is a high-resolution model of the forest. This study presents the first approach for tropical forest characterization at a fine scale using remote sensing data. The multi-modal lidar point cloud is decomposed into 3D clusters that correspond to single trees by means of a technique called Adaptive Mean Shift Segmentation (AMS3D). The ability of the corresponding individual tree metrics (tree height, crown area and crown volume) for the estimation of above ground biomass (agb) over the 50 ha CTFS plot in Barro Colorado Island is here assessed. We conclude that our approach is able to map the agb spatial distribution with an error of nearly 12% (RMSE=28 Mg ha-1) compared with field-based estimates over 1ha plots.

  12. Seagrass biomass and productivity in the Florida Keys, USA: ground-level and airborne measurements

    NASA Astrophysics Data System (ADS)

    Yarbro, L.; Carlson, P. R., Jr.; McHan, C.; Carlson, D. F.; Hu, C.; Danielson, T.; Durnan, B.; English, D. C.; Muller-Karger, F. E.; Yates, K. K.; Herwitz, S.; Merrill, J.; Mewes, T.

    2013-12-01

    Seagrass communities serve as essential habitat for fish and shellfish, and recent research indicates that they can play a significant role in reducing ocean acidification. As part of a collaborative project funded by the NASA ROSES program and administered by the NASA UAV Collaborative, we collected hyperspectral imagery of seagrass beds and measured productivity of Thalassia testudinum at Sugarloaf Key, Florida, in May 2012, October 2012, and May 2013. Our primary goal was to evaluate the utility of hyperspectral sensors, in general, and UAV platforms, in specific, to measure seagrass health and productivity. Airborne measurements using the AISA Eagle hyperspectral imaging system were carried out simultaneously with ground measurements of Thalassia fluorescence, oxygen metabolism, growth, and biomass, as well as remote sensing reflectance and several in situ optical properties. Water depths at the study site ranged from less than 1 m to 5 m. Phytoplankton chlorophyll-a concentrations (0.09-0.72 ug l-1), ag(440) (0-0.02 m-1), and turbidity (0.12-4.1 ntu) were relatively low for all three deployments, facilitating the collection of excellent imagery and application of water-column radiative-transfer corrections. Aboveground Thalassia and macroalgal biomass, at 18 sites in the study area, ranged from 210 to 690 and 11 to 590 gDW m-2, respectively. One-sided green leaf area index of Thalassia ranged from 0.7 to 3.0. Preliminary findings show that the sensitivity of relationships between seagrass productivity and biomass parameters and remotely-sensed habitat spectra is reduced with increasing water depth and, even in shallow water, is complicated by epiphytic algae and sediment coverage of leaf surfaces.

  13. Integration for Airborne Dust Prediction Systems and Vegetation Phenology to Track Pollen for Asthma Alerts in Public Health Decision Support Systems

    NASA Technical Reports Server (NTRS)

    Luvall, J. C.; Sprigg, W. A.; Nickovic, S.; Huete, A.; Budge, A.; Flowers, L.

    2008-01-01

    The objective of the program is to assess the feasibility of combining a dust transport model with MODIS derived phenology to study pollen transport for integration with a public health decision support system. The use of pollen information has specifically be identified as a critical need by the New Mexico State Health department for inclusion in the Environmental Public Health Tracking (EPHT) program. Material and methods: Pollen can be transported great distances. Local observations of plan phenology may be consistent with the timing and source of pollen collected by pollen sampling instruments. The Dust REgional Atmospheric Model (DREAM) is an integrated modeling system designed to accurately describe the dust cycle in the atmosphere. The dust modules of the entire system incorporate the state of the art parameterization of all the major phases of the atmospheric dust life such as production, diffusion, advection, and removal. These modules also include effects of the particles size distribution on aerosol dispersion. The model was modified to use pollen sources instead of dust. Pollen release was estimated based on satellite-derived phenology of key plan species and vegetation communities. The MODIS surface reflectance product (MOD09) provided information on the start of the plant growing season, growth stage, and pollen release. The resulting deterministic model is useful for predicting and simulating pollen emission and downwind concentration to study details of phenology and meteorology and their dependencies. The proposed linkage in this project provided critical information on the location timing and modeled transport of pollen directly to the EPHT> This information is useful to support the centers for disease control and prevention (CDC)'s National EPHT and the state of New Mexico environmental public health decision support for asthma and allergies alerts.

  14. Underground Coal Mining: Relationship between Coal Dust Levels and Pneumoconiosis, in Two Regions of Colombia, 2014

    PubMed Central

    Torres Rey, Carlos Humberto; Ibañez Pinilla, Milciades; Briceño Ayala, Leonardo; Checa Guerrero, Diana Milena; Morgan Torres, Gloria; Groot de Restrepo, Helena; Varona Uribe, Marcela

    2015-01-01

    In Colombia, coal miner pneumoconiosis is considered a public health problem due to its irreversibility, high cost on diagnosis, and lack of data related to its prevalence in the country. Therefore, a cross-sectional study was carried out in order to determine the prevalence of pneumoconiosis in underground coal mining workers in two regions of Colombia. The results showed a 35.9% prevalence of pneumoconiosis in the study group (42.3% in region 1 and 29.9% in region 2). An association was found between a radiologic diagnosis of pneumoconiosis and a medium risk level of exposure to carbon dust (OR: 2.901, 95% CI: 0.937, 8.982), medium size companies (OR: 2.301, 95% CI: 1.260–4.201), length of mining work greater than 25 years (OR: 3.222, 95% CI: 1.806–5.748), and a history of smoking for more than one year (OR: 1.479, 95% CI: 0.938–2.334). These results establish the need to generate an intervention strategy aimed at preventing the identified factors, as well as a timely identification and effective treatment of pneumoconiosis in coal miners, in which the commitment of the General Health and Social Security System and the workers compensation system is ensured. PMID:26366418

  15. Underground Coal Mining: Relationship between Coal Dust Levels and Pneumoconiosis, in Two Regions of Colombia, 2014.

    PubMed

    Torres Rey, Carlos Humberto; Ibañez Pinilla, Milciades; Briceño Ayala, Leonardo; Checa Guerrero, Diana Milena; Morgan Torres, Gloria; Groot de Restrepo, Helena; Varona Uribe, Marcela

    2015-01-01

    In Colombia, coal miner pneumoconiosis is considered a public health problem due to its irreversibility, high cost on diagnosis, and lack of data related to its prevalence in the country. Therefore, a cross-sectional study was carried out in order to determine the prevalence of pneumoconiosis in underground coal mining workers in two regions of Colombia. The results showed a 35.9% prevalence of pneumoconiosis in the study group (42.3% in region 1 and 29.9% in region 2). An association was found between a radiologic diagnosis of pneumoconiosis and a medium risk level of exposure to carbon dust (OR: 2.901, 95% CI: 0.937, 8.982), medium size companies (OR: 2.301, 95% CI: 1.260-4.201), length of mining work greater than 25 years (OR: 3.222, 95% CI: 1.806-5.748), and a history of smoking for more than one year (OR: 1.479, 95% CI: 0.938-2.334). These results establish the need to generate an intervention strategy aimed at preventing the identified factors, as well as a timely identification and effective treatment of pneumoconiosis in coal miners, in which the commitment of the General Health and Social Security System and the workers compensation system is ensured. PMID:26366418

  16. Domestic airborne black carbon levels and 8-isoprostane in exhaled breath condensate among children in New York City☆

    PubMed Central

    Rosa, Maria Jose; Yan, Beizhan; Chillrud, Steven N.; Acosta, Luis M.; Divjan, Adnan; Jacobson, Judith S.; Miller, Rachel L.; Goldstein, Inge F.; Perzanowski, Matthew S.

    2015-01-01

    Background Exposure to airborne black carbon (BC) has been associated with asthma development, respiratory symptoms and decrements in lung function. However, the mechanism through which BC may lead to respiratory symptoms has not been completely elucidated. Oxidative stress has been suggested as a potential mechanism through which BC might lead to adverse health outcomes. Exhaled breath condensate (EBC) allows for the non-invasive collection of airway lining fluid containing biomarkers of oxidative stress like 8-isoprostane, a stable by-product of lipid peroxidation. Therefore, we sought to characterize the association between domestic airborne BC concentrations and 8-isoprostane in EBC. Materials and methods Seven- and eight-year-old children participated in an asthma case–control study in New York City. During home visits, air samples and EBC were collected. Seven day averages of domestic levels of particulate matter <2.5 µm (PM2.5), BC and environmental tobacco smoke (ETS) were measured. Urea and 8-isoprostane were measured by liquid chromatography tandem mass spectrometry (LC/MS/MS) in EBC. Results In univariate models, PM2.5 and BC, but not ETS, were significantly associated with increases in 8-isoprostane in the EBC (β = 0.006 and β = 0.106 respectively, p < 0.05 for both). These associations remained statistically significant for both PM2.5 and BC after adjustment for covariates. In a co-pollutant model including PM2.5, BC and ETS, only BC remained a statistically significant predictor of 8-isoprostane (p < 0.05). Conclusions Our findings suggest the BC fraction of PM might contain exposure relevant to increased oxidative stress in the airways. PMID:25262082

  17. Can Lightning Produce Significant Levels of Mass-Independent Oxygen Isotopic Fractionation in Nebular Dust?

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A.; Paquette, John A.; Farquhar, Adam

    2012-01-01

    Based on recent evidence that oxide grains condensed from a plasma will contain oxygen that is mass independently fractionated compared to the initial composition of the vapor, we present a first attempt to evaluate the potential magnitude of this effect on dust in the primitive solar nebula. This assessment relies on previous studies of nebular lightning to provide reasonable ranges of physical parameters to form a very simple model to evaluate the plausibility that lightning could affect a significant fraction of nebular dust and that such effects could cause a significant change in the oxygen isotopic composition of solids in the solar nebula over time. If only a small fraction of the accretion energy is dissipated as lightning over the volume of the inner solar nebula, then a large fraction of nebular dust will be exposed to lightning. If the temperature of such bolts is a few percent of the temperatures measured in terrestrial discharges, then dust will vaporize and recondense in an ionized environment. Finally, if only a small average decrease is assumed in the O-16 content of freshly condensed dust, then over the last 5 million years of nebular accretion the average delta O-17 of the dust could increase by more than 30 per mil. We conclude that it is possible that the measured " slope 1" oxygen isotope line measured in meteorites and their components represents a time-evolution sequence of nebular dust over the last several million years of nebular evolution O-16-rich materials formed first, then escaped further processing as the average isotopic composition of the dust graduaUy became increasingly depleted in O-16 .

  18. Effect of repeated freeze/thawing of household dust extracts on β-(1,3)-glucan levels.

    PubMed

    Siebers, Robert; Wu, Francis F F; Shorter, Caroline; Pierse, Nevil; Crane, Julian

    2015-01-01

    β-(1,3)-glucan exposure from household dust has been shown to be associated with respiratory symptoms and thus is increasingly being measured in epidemiological studies. Various factors are known to influence its measurement; however, no studies have assessed the effects of sample extract freeze-thawing on β-(1,3)-glucan. The aim of this study was to assess the effects of repeated freeze-thawing of household dust extracts on levels of β-(1,3)-glucan. Forty random household dust samples were extracted with 0.3 M NaOH and aliquots of extracts stored at -20 °C were subjected to one, two, and three freeze-thaw cycles. They were analyzed for β-(1,3)-glucan by the Limulus amoebocyte assay (LAL) and results compared to freshly extracted samples (paired Pearson's t-test on logged values). Initial freezing of house dust extracts results in a significant decline in β-(1,3)-glucan. However, repeated freeze/thawing (up to three times) does not results in any further decline in β-(1,3)-glucan levels. PMID:25411832

  19. Influence of social and environmental factors on dust, lead, hand lead, and blood lead levels in young children

    SciTech Connect

    Bornschein, R.L.; Succop, P.; Dietrich, K.N.; Clark, C.S.; Que Hee, S.; Hammond, P.B.

    1985-10-01

    The roles of environmental and behavioral factors in determining blood lead levels were studied in a cohort of young children living in an urban environment. The subjects were observed at 3-month intervals from birth to 24 months of age. Repeated measurements were made of the children's blood lead levels, environmental levels of lead in house dust, and in the dust found on the children's hands. A qualitative rating of the residence and of the socioeconomic status of the family was obtained. Interviews and direct observation of parent and child at home were used to evaluate various aspects of caretaker-child interactions. Data analysis consisted of a comparison of results obtained by (a) simple correlational analysis, (b) multiple regression analysis, and (c) structural equations analysis. The results demonstrated that structural equation modeling offers a useful approach to unraveling the complex interactions present in the data set. In this preliminary analysis, the suspected relationship between the levels of lead in house dust and on hands and the blood lead level was clearly demonstrated. Furthermore, the analyses indicated an important interplay between environmental sources and social factors in the determination of hand lead and blood lead levels in very young children.

  20. Exposure to grain dust in Great Britain.

    PubMed

    Spankie, Sally; Cherrie, John W

    2012-01-01

    Airborne grain dust is a complex mixture of fragments of organic material from grain, plus mineral matter from soil, and possible insect, fungal, or bacterial contamination or their toxic products, such as endotoxin. In the 1990s, grain workers in Britain were frequently exposed to inhalable dust >10 mg.m(-3) (8 h), with particularly high exposures being found at terminals where grain was imported or exported and in drying operations (personal exposure typically approximately 20 mg.m(-3)). Since then, the industry has made substantial progress in improving the control of airborne dust through better-designed processes, increased automation, and an improved focus on product quality. We have used information from the published scientific literature and a small survey of industry representatives to estimate current exposure levels. These data suggest that current long-term exposure to inhalable dust for most workers is on average less than approximately 3 mg.m(-3), with perhaps 15-20% of individual personal exposures being >10 mg.m(-3). There are no published data from Britain on short-term exposure during cleaning and other tasks. We have estimated average levels for a range of tasks and judge that the highest levels, for example during some cleaning activities and certain process tasks such as loading and packing, are probably approximately10 mg.m(-3). Endotoxin levels were judged likely to be <10⁴ EU m(-3) throughout the industry provided inhalable dust levels are <10 mg.m(-3). There are no published exposure data on mycotoxin, respirable crystalline silica, and mite contamination but these are not considered to present widespread problems in the British industry. Further research should be carried out to confirm these findings. PMID:21976307

  1. Modeling Respiratory Toxicity of Authentic Lunar Dust

    NASA Technical Reports Server (NTRS)

    Santana, Patricia A.; James, John T.; Lam, Chiu-Wing

    2010-01-01

    The lunar expeditions of the Apollo operations from the 60 s and early 70 s have generated awareness about lunar dust exposures and their implication towards future lunar explorations. Critical analyses on the reports from the Apollo crew members suggest that lunar dust is a mild respiratory and ocular irritant. Currently, NASA s space toxicology group is functioning with the Lunar Airborne Dust Toxicity Assessment Group (LADTAG) and the National Institute for Occupational Safety and Health (NIOSH) to investigate and examine toxic effects to the respiratory system of rats in order to establish permissible exposure levels (PELs) for human exposure to lunar dust. In collaboration with the space toxicology group, LADTAG and NIOSH the goal of the present research is to analyze dose-response curves from rat exposures seven and twenty-eight days after intrapharyngeal instillations, and model the response using BenchMark Dose Software (BMDS) from the Environmental Protection Agency (EPA). Via this analysis, the relative toxicities of three types of Apollo 14 lunar dust samples and two control dust samples, titanium dioxide (TiO2) and quartz will be determined. This will be executed for several toxicity endpoints such as cell counts and biochemical markers in bronchoaveolar lavage fluid (BALF) harvested from the rats.

  2. Climatology of nocturnal low-level jets over North Africa and implications for modeling mineral dust emission

    NASA Astrophysics Data System (ADS)

    Fiedler, S.; Schepanski, K.; Heinold, B.; Knippertz, P.; Tegen, I.

    2013-06-01

    This study presents the first climatology for the dust emission amount associated with Nocturnal Low-Level Jets (NLLJs) in North Africa. These wind speed maxima near the top of the nocturnal boundary layer can generate near-surface peak winds due to shear-driven turbulence in the course of the night and the NLLJ breakdown during the following morning. The associated increase in the near-surface wind speed is a driver for mineral dust emission. A new detection algorithm for NLLJs is presented and used for a statistical assessment of NLLJs in 32 years of ERA-Interim reanalysis from the European Centre for Medium-Range Weather Forecasts. NLLJs occur in 29% of the nights in the annual and spatial mean. The NLLJ climatology shows a distinct annual cycle with marked regional differences. Maxima of up to 80% NLLJ frequency are found where low-level baroclinicity and orographic channels cause favorable conditions, e.g., over the Bodélé Depression, Chad, for November-February and along the West Saharan and Mauritanian coast for April-September. Downward mixing of NLLJ momentum to the surface causes 15% of mineral dust emission in the annual and spatial mean and can be associated with up to 60% of the total dust amount in specific areas, e.g., the Bodélé Depression and south of the Hoggar-Tibesti Channel. The sharp diurnal cycle underlines the importance of using wind speed information with high temporal resolution as driving fields for dust emission models.

  3. Factors affecting lead, cadmium, and arsenic levels in house dust in a smelter town in eastern Germany

    SciTech Connect

    Meyer, I.; Heinrich, J. . Inst. fuer Epidemiologie); Lippold, U. )

    1999-07-01

    Hettstedt, a city in eastern Germany with a long history of mining and smelting of nonferrous ores, has several industrial sources of heavy metals. The indoor exposure to metals of children (5 to 14 years old) in the Hettstedt area was assessed by measuring the levels of lead, cadmium, and arsenic contamination in sedimented house dust. Factors which influence the dust loading rate and the surface loading rates of these contaminants in house dust were investigated. The geometric mean of the dust loading rate was 8.9 mg/m[sup 2] day. The geometric means of surface loading rates were 1.14, 0.024, and 0.023 [micro]g/m[sup 2] day for lead, cadmium, and arsenic, respectively. Factors that were significantly associated with surface loading rates included the city area of residence, automobile traffic near home, parent with occupational exposure to heavy metals, type of heating, housing characteristics, whether child's home is damp, number of persons living in the child's home,and parents' education. The most significant of these factors was the city area of residence, which reflects the distance from the metal sources; this factor accounted for about half of the variances explained by the regression models.

  4. Dust Measurements in Tokamaks

    SciTech Connect

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

    2008-04-23

    Dust production and accumulation impose safety and operational concerns for ITER. Diagnostics to monitor dust levels in the plasma as well as in-vessel dust inventory are currently being tested in a few tokamaks. 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 DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering resolves size of particles between 0.16-1.6 {micro}m in diameter; 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 2D with a single camera or 3D using multiple cameras, but determination of particle size is problematic. In order to calibrate diagnostics and benchmark dust dynamics modeling, pre-characterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase of carbon atomic, C2 dimer, and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.

  5. Dust storms - Great Plains, Africa, and Mars

    NASA Technical Reports Server (NTRS)

    Woiceshyn, P. M.; Krauss, R.; Minzner, R.; Shenk, W.

    1977-01-01

    Dust storms in the Great Plains of North America and in the Sahara Desert are analyzed on the basis of imagery from the geostationary Synchronous Meteorological Satellite. The onset time, location and areal extent of the dust storms are studied. Over land surfaces, contrast enhancement techniques are needed to obtain an adequate picture of dust storm development. In addition, infrared imagery may provide a means of monitoring the strong horizontal temperature gradients characteristic of dust cloud boundaries. Analogies between terrestrial dust storms and the airborne rivers of dust created by major Martian dust storms are also drawn.

  6. Evaluation and Application of the RD50 for Determining Acceptable Exposure Levels of Airborne Sensory Irritants for the General Public

    PubMed Central

    Kuwabara, Yu; Alexeeff, George V.; Broadwin, Rachel; Salmon, Andrew G.

    2007-01-01

    Background The RD50 (exposure concentration producing a 50% respiratory rate decrease) test evaluates airborne chemicals for sensory irritation and has become an American Society for Testing and Materials (ASTM) standard method. Past studies reported good correlations (R2) between RD50s and the occupational exposure limits, particularly threshold limit values (TLVs). Objective The main purpose of this study was to examine the relationship between RD50s and human sensory irritation responses in a quantitative manner, particularly for chemicals that produce burning sensation of the eyes, nose, or throat, based on lowest observed adverse effect levels (LOAELs) reported for human subjects. Methods We compared RD50s with LOAELs and acute reference exposure levels (RELs). RELs, developed by the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment, represent a level at which no adverse effects are anticipated after exposure. We collected RD50s from the published literature and evaluated them for consistency with ASTM procedures. We identified LOAELs for human irritation and found 25 chemicals with a corresponding RD50 in mice. Discussion We found the relationship between RD50s and LOAELs as log RD50 = 1.16 (log LOAEL) + 0.77 with an R2 value of 0.80. This strong correlation supports the use of the RD50 in establishing exposure limits for the public. We further identified 16 chemical irritants with both RD50s and corresponding acute RELs, and calculated the relationship as log RD50 = 0.71 (log REL) + 2.55 with an R2 value of 0.71. This relationship could be used to identify health protective values for the public to prevent respiratory or sensory irritation. Conclusion Consequently, we believe that the RD50 has benefits for use in setting protective levels for the health of both workers and the general population. PMID:18007993

  7. PM10 concentration levels at an urban and background site in Cyprus: the impact of urban sources and dust storms.

    PubMed

    Achilleos, Souzana; Evans, John S; Yiallouros, Panayiotis K; Kleanthous, Savvas; Schwartz, Joel; Koutrakis, Petros

    2014-12-01

    Air quality in Cyprus is influenced by both local and transported pollution, including desert dust storms. We examined PM10 concentration data collected in Nicosia (urban representative) from April 1, 1993, through December 11, 2008, and in Ayia Marina (rural background representative) from January 1, 1999, through December 31, 2008. Measurements were conducted using a Tapered Element Oscillating Micro-balance (TEOM). PM10 concentrations, meteorological records, and satellite data were used to identify dust storm days. We investigated long-term trends using a Generalized Additive Model (GAM) after controlling for day of week, month, temperature, wind speed, and relative humidity. In Nicosia, annual PM10 concentrations ranged from 50.4 to 63.8 μg/m3 and exceeded the EU annual standard limit enacted in 2005 of 40 μg/m3 every year A large, statistically significant impact of urban sources (defined as the difference between urban and background levels) was seen in Nicosia over the period 2000-2008, and was highest during traffic hours, weekdays, cold months, and low wind conditions. Our estimate of the mean (standard error) contribution of urban sources to the daily ambient PM10 was 24.0 (0.4) μg/m3. The study of yearly trends showed that PM10 levels in Nicosia decreased from 59.4 μg/m3 in 1993 to 49.0 μg/m3 in 2008, probably in part as a result of traffic emission control policies in Cyprus. In Ayia Marina, annual concentrations ranged from 27.3 to 35.6 μg/m3, and no obvious time trends were observed. The levels measured at the Cyprus background site are comparable to background concentrations reported in other Eastern Mediterranean countries. Average daily PM10 concentrations during desert dust storms were around 100 μg/m3 since 2000 and much higher in earlier years. Despite the large impact ofdust storms and their increasing frequency over time, dust storms were responsible for a small fraction of the exceedances of the daily PM10 limit. Implications: This

  8. An investigation on factors influencing dust accumulation on CSP mirrors

    NASA Astrophysics Data System (ADS)

    Pennetta, S.; Yu, S.; Borghesani, P.; Cholette, M.; Barry, John; Guan, Z.

    2016-05-01

    The profitability of a CSP plant is highly affected by the efficiency of the solar field: it is essential to maintain mirrors' reflectivity at high level to avoid thermal power loss. Dust fouling is the main cause of reflectivity loss and cleaning of mirrors is a crucial activity to restore economical level of reflectivity. However, the high cost of cleaning operations requires the study and identification of a balanced plan for the dust removal. The dust generation and transport to the plant site is the first mechanism that needs to be modelled to identify the optimal schedule for cleaning operations and it is highly dependent on weather conditions. Several studies have suggested a dependency of reflectors performance with humidity level, frequency of rainfalls, wind and mirrors' tilting angle, however rarely quantitative correlation studies have been performed to validate these hypotheses. The aim of this research is to provide an in-depth insight on interaction between the main parameters and airborne dust concentration, providing quantitative information for the development of future mirror dusting models. Outcomes evidence the crucial role of high winds responsible of dust concentration in conjunction with higher wind direction frequencies in the range 60-120°. Actually, in this scenario a perfectly monotonic increase of dust accumulation in the air has been observed with high correspondence of wind direction. A very low effect is provided by the ambient temperature as the contribution of the barometric pressure.

  9. Pollution level and health risk assessment of road dust from an expressway.

    PubMed

    Faiz, Yasir; Siddique, Naila; Tufail, Muhammad

    2012-01-01

    Thirteen road dust and four soil samples were analyzed using instrumental neutron activation analysis (INAA) to determine the elemental composition of road dust collected from Islamabad Expressway. The amounts of most of the elements determined were generally in the lower range of the global data with the exception of Ce, Nd, Sn and Zr, which were measured at higher concentrations in Islamabad. The magnitudes of Enrichment Factors (EFs) showed that the area around Islamabad Expressway is low to moderately polluted especially by elements such as Mg and Sb. Elemental health risk was assessed through dose calculations for carcinogenic and non-carcinogenic metals; and by the determination of LADD (lifetime average daily dose). The carcinogenic metals studied showed the following variation in their LADD values; Cr>Ni>Co>Cd>As. Dose calculations for non-cancerous and cancerous elements showed the data obtained to lie within the safe threshold of 10(-3)-10(-6) mg kg(-1) day(-1) for most elements. The Soil-based elements Al, Fe, K, Mg, Na and Ti were the exception and originated from the exposed soil around the highway. Moreover highest Hazard Index (HI) was found to be associated with the presence of Al, Cr, Pb and V in road dust showing soil, transport and industry to be the major sources of road dust. PMID:22423987

  10. Levels of polybrominated diphenyl ethers in indoor dust and human exposure estimates from Makurdi, Nigeria.

    PubMed

    Olukunle, O I; Okonkwo, O J; Sha'ato, R; Wase, G A

    2015-10-01

    Information on polybrominated diphenyl ethers (PBDEs) in the indoor environment in developing countries is still relatively scarce. In this study, house (n=10) and office (n=11) dusts samples collected from Makurdi, Benue State Nigeria were extracted and analysed for most abundant PBDEs congeners in the environment. Soxhlet extraction followed by GC-EIMS was employed for the measurement of PBDEs (BDE-47, -100, -99, -154, -153, -183 and -209). The mean concentration of ∑7 PBDEs ranged from 57ngg(-1) to 80ngg(-1) and a median value of 45ngg(-1)and 63ngg(-1) were obtained for house and office dust respectively. The daily exposure and ingestion dose estimates were calculated based on the assumption that 30mg and 60mgday(-1) dust represent the ingestion rate. In addition, the corresponding time spent indoors was assumed to be 87.5% (adult) and 69% (children) in homes and 22% in offices and day care. The average value exposure rate of ∑7PBDEs for children and adults were 2ngday(-1) and 0.84ngday(-1) respectively. The results in the present study, showed higher exposure estimates for both children and adults' in house dust from Nigeria compared to South Africa. PMID:26117364

  11. [Building Change Detection Based on Multi-Level Rules Classification with Airborne LiDAR Data and Aerial Images].

    PubMed

    Gong, Yi-long; Yan, Li

    2015-05-01

    The present paper proposes a new building change detection method combining Lidar point cloud with aerial image, using multi-level rules classification algorithm, to solve building change detection problem between these two kinds of heterogeneous data. Then, a morphological post-processing method combined with area threshold is proposed. Thus, a complete building change detection processing flow that can be applied to actual production is proposed. Finally, the effectiveness of the building change detection method is evaluated, processing the 2010 airborne LiDAR point cloud data and 2009 high resolution aerial image of Changchun City, Jilin province, China; in addition, compared with the object-oriented building change detection method based on support vector machine (SVM) classification, more analysis and evaluation of the suggested method is given. Experiment results show that the performance of the proposed building change detection method is ideal. Its Kappa index is 0. 90, and correctness is 0. 87, which is higher than the object-oriented building change detection method based on SVM classification. PMID:26415454

  12. Exposure to airborne microorganisms and endotoxin in herb processing plants.

    PubMed

    Dutkiewicz, J; Krysińska-Traczyk, E; Skórska, C; Sitkowska, J; Prazmo, Z; Golec, M

    2001-01-01

    Microbiological air sampling was performed in two herb processing plants located in eastern Poland. Air samples for determination of the levels of bacteria, fungi, dust and endotoxin were collected at 14 sites during cleaning, cutting, grinding, sieving, sorting and packing of 11 kinds of herbs (nettle, caraway, birch, celandine, marjoram, mint, peppermint, sage, St. John's wort, calamus, yarrow), used for production of medications, cosmetics and spices. It was found that processing of herbs was associated with a very high pollution of the air with bacteria, fungi, dust and endotoxin. The numbers of microorganisms (bacteria and fungi) in the air of herb processing plants ranged within 40.6-627.4 x 10(3) cfu/m3 (mean +/- S.D = 231.4 +/- 181.0 x 10(3) cfu/m3). The greatest concentrations were noted at the initial stages of production cycle, during cleaning, cutting and grinding of herbs. The numbers of airborne microorganisms were also significantly (p<0.0001) related to the kind of processed herb, being the greatest at processing marjoram, nettle, yarrow and mint. The values of the respirable fraction of airborne microflora in the examined facilities varied within a fairly wide range and were between 14.7-67.7%. The dominant microorganisms in the air of herb processing plants were mesophilic bacteria, among which endospore-forming bacilli (Bacillus spp.) and actinomycetes of the species Streptomyces albus were most numerous. Among Gram-negative bacteria, the most common was endotoxin-producing species Alcaligenes faecalis. Altogether, 37 species or genera of bacteria and 23 species or genera of fungi were identified in the air of herb processing plants, of these, 11 and 10 species or genera respectively were reported as having allergenic and/or immunotoxic properties. The concentrations of dust and bacterial endotoxin in the air of herb processing plants were large with extremely high levels at some sampling sites. The concentrations of airborne dust ranged within 3

  13. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Determination of dust concentration. 33.32... MINES Test Requirements § 33.32 Determination of dust concentration. (a) Concentrations of airborne dust... microscopic technique shall be employed in determining concentrations of dust in terms of millions...

  14. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Determination of dust concentration. 33.32... MINES Test Requirements § 33.32 Determination of dust concentration. (a) Concentrations of airborne dust... microscopic technique shall be employed in determining concentrations of dust in terms of millions...

  15. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Determination of dust concentration. 33.32... MINES Test Requirements § 33.32 Determination of dust concentration. (a) Concentrations of airborne dust... microscopic technique shall be employed in determining concentrations of dust in terms of millions...

  16. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Determination of dust concentration. 33.32... MINES Test Requirements § 33.32 Determination of dust concentration. (a) Concentrations of airborne dust... microscopic technique shall be employed in determining concentrations of dust in terms of millions...

  17. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Determination of dust concentration. 33.32... MINES Test Requirements § 33.32 Determination of dust concentration. (a) Concentrations of airborne dust... microscopic technique shall be employed in determining concentrations of dust in terms of millions...

  18. Plasma C3d levels of young farmers correlate with respirable dust exposure levels during normal work in swine confinement buildings.

    PubMed

    Hoffmann, Hans Jürgen; Iversen, Martin; Brandslund, Ivan; Sigsgaard, Torben; Omland, Øyvind; Oxvig, Claus; Holmskov, Uffe; Bjermer, Leif; Jensenius, Jens Christian; Dahl, Ronald

    2003-01-01

    Work in swine confinement buildings leads to an inflammatory response and may be associated with increased levels of acute phase proteins. We compared the inflammatory response of a control group of young former farm workers with age-matched former farm workers who had previously developed the lower airway symptoms of wheeze, cough, tightness of the chest during work in swine confinement buildings, and because of these symptoms had stopped work. Both groups were subjected to an experimental exposure in a swine confinement building for 3 hours. Complement activation and acute phase proteins were measured in blood samples and broncho-alveolar lavage. Plasma C3d levels correlated with respirable dust, significantly so for individual cases and for the whole cohort. Plasma C3, fibrinogen and alpha (1) -acid glycoprotein peaked 1 and 6 h after exposure start, mannan-binding lectin, C-reactive protein and alpha(1)-antitrypsin peaked after 2 h. Surfactant protein D (SP-D) and alpha (2) -macroglobulin were downregulated. In lavage, only SP-D, alpha (2)-macroglobulin and fibronectin were detected. FEV(1), FVC, TLC and FEV(25-75) did not vary during exposure. There was complement activation in response to respiratory dust, more so amongst cases than in the control group. Acute exposure, with work related levels of organic dust containing endotoxin, leads to a weak systemic inflammatory response. PMID:12852733

  19. 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

  20. 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

    2015-01-01

    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 (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. PMID:26274959

  1. Efficacy of an In-home Test Kit in Reducing Dust Mite Allergen Levels: Results of a Randomized Controlled Pilot Study

    PubMed Central

    Winn, Amber K.; Salo, Päivi M.; Klein, Cynthia; Sever, Michelle L.; Harris, Shawn F.; Johndrow, David; Crockett, Patrick W.; Cohn, Richard D.; Zeldin, Darryl C.

    2015-01-01

    Background Dust mite allergens can induce allergic sensitization and exacerbate asthma symptoms. Although dust mite reduction and control strategies exist, few asthmatics employ them. Objectives We examined whether an in-home test kit, which quantifies dust mite allergen levels, resulted in behavioral changes in implementation and maintenance of mite reduction strategies and helped reduce allergen levels in homes of dust mite-sensitive children. Methods We enrolled 60 households of children aged 5-15 with parent-reported dust mite allergy into a randomized controlled trial. Intervention homes (N=30) received educational material about reducing dust mites and test kits at 1,2,5, and 8 months. Control homes (N=30) received only educational material. At baseline, 6 and 12 months, study staff visited all homes, collected dust samples from 3 locations and obtained information about parents’ mite reduction behaviors by questionnaire. Allergen concentrations (Der f 2/Der p2) in dust were assessed by immunoassays. After adjusting for visit and location, allergen concentrations in intervention and control homes were compared using mixed effects model analysis. Results In the intervention homes, allergen concentrations in the child's bedroom and living room floors were significantly reduced over time compared to control homes. Although not all location-specific differences in allergen concentrations were statistically significant, combining data across locations, there was a differential reduction in allergen concentrations in the intervention group versus the control group (p =0.02). Conclusion The use of in-home test kits along with education may beneficially influence behaviors and attitudes towards dust mite reduction strategies and help reduce residential dust mite allergen levels. PMID:26308287

  2. Low-flow, long-term air sampling under normal domestic activity to measure house dust mite and cockroach allergens.

    PubMed

    Park, Jung Won; Kim, Cheol Woo; Kang, Dae Bong; Lee, In Young; Choi, Soo Young; Yong, Tai-Soon; Shin, Dong Cheon; Kim, Kyu Earn; Hong, Chein-Soo

    2002-01-01

    Successful applications of air sampling for the quantification of exposure to indoor allergens have been reported, but its efficiency is still controversial. We evaluated whether the low-flow, long-term air sampling in normal domestic activity conditions can quantify the exposure of house dust mites (HDM) and cockroaches (CR) allergens or not. Airborne Der f 1 and Bla g 1 were captured with a personal air sampler in 25 bedrooms during normal domestic activity. Quantification of the major allergens in the reservoir dust and the extraction of the air sampler filters were done with two-site ELISA kits. Airborne Der f 1 was measured above the threshold level of detection in 15 houses (60%). Detection rate of airborne Der f 1 was significantly higher in those houses where D. farinae was microscopically found in the reservoir dusts (76.5% vs. 25%, chi 2 = 6.0, p = 0.014). Airborne Der f 1 was more frequently detected in the houses with higher Der f 1 (> or = 10 micrograms/g dust) in bedding reservoir dust than the other group (91% vs. 35.7%, chi 2 = 7.819, p = 0.005), and the median value of airborne Der f 1 was also significantly higher in that group (14.0 pg/m3 vs. below detection limit, p = 0.002). Airborne Der f 1 was significantly correlated with Der f 1 in bedding reservoir dust (r = 0.591, p < 0.01). Airborne Bla g 1 was measured with ELISA in 16 houses (64%), and it was more frequently detected in the houses where the CRs were captured by adhesive traps (91% vs. 57%, chi 2 = 3,484, p = 0.06). The median concentration of Bla g 1 in the filter was also higher in the houses with captured CRs (0.12 vs. 0.05 mU/m3, p = 0.06), but the level of Bla g 1 did not correlate with that of the bedding dusts or the floor dusts of kitchen. These results suggested that airborne HDM or CR allergens could be measured by low-flow, long-term air sampling, and that it might be one of appropriate modalities for evaluating personal exposure to HDM and CR allergens. PMID:12926189

  3. PM10 Concentration levels at an urban and background site in Cyprus: The impact of urban sources and dust storms

    PubMed Central

    Achilleos, Souzana; Evans, John S.; Yiallouros, Panayiotis K.; Kleanthous, Savvas; Schwartz, Joel; Koutrakis, Petros

    2016-01-01

    Air quality in Cyprus is influenced by both local and transported pollution including desert dust storms. We examined PM10 concentration data collected in Nicosia (urban representative) from April 1, 1993 through December 11, 2008, and Ayia Marina (rural background representative) from January 1, 1999 through December 31, 2008. Measurements were conducted using a Tapered Element Oscillating Micro-balance (TEOM). PM10 concentrations, meteorological records and satellite data were used to identify dust storm days. We investigated long term trends using a Generalized Additive Model (GAM) after controlling for day of week, month, temperature, wind speed, and relative humidity. In Nicosia, annual PM10 concentrations ranged from 50.4 to 63.8 μg/m3 and exceeded the EU annual standard limit enacted in 2005 of 40 μg/m3 every year. A large, statistically significant impact of urban sources (defined as the difference between urban and background levels) was seen in Nicosia over the period 2000–2008, and was highest during traffic hours, weekdays, cold months, and low wind conditions. Our estimate of the mean (standard error) contribution of urban sources to the daily ambient PM10 was 24.0 (0.4) μg/m3. The study of yearly trends showed that PM10 levels in Nicosia decreased from 59.4 μg/m3 in 1993 to 49.0 μg/m3 in 2008, probably in part as a result of traffic emission control policies in Cyprus. In Ayia Marina, annual concentrations ranged from 27.3 to 35.6 μg/m3, and no obvious time trends were observed. The levels measured at the Cyprus background site are comparable to background concentrations reported in other Eastern Mediterranean countries. Average daily PM10 concentrations during desert dust storms were around 100 μg/m3 since 2000 and much higher in earlier years. Despite the large impact of dust storms and their increasing frequency over time, dust storms were responsible for a small fraction of the exceedances of the daily PM10 limit. PMID:25562931

  4. Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations

    NASA Astrophysics Data System (ADS)

    Ryder, C. L.; McQuaid, J. B.; Flamant, C.; Rosenberg, P. D.; Washington, R.; Brindley, H. E.; Highwood, E. J.; Marsham, J. H.; Parker, D. J.; Todd, M. C.; Banks, J. R.; Brooke, J. K.; Engelstaedter, S.; Estelles, V.; Formenti, P.; Garcia-Carreras, L.; Kocha, C.; Marenco, F.; Sodemann, H.; Allen, C. J. T.; Bourdon, A.; Bart, M.; Cavazos-Guerra, C.; Chevaillier, S.; Crosier, J.; Darbyshire, E.; Dean, A. R.; Dorsey, J. R.; Kent, J.; O'Sullivan, D.; Schepanski, K.; Szpek, K.; Trembath, J.; Woolley, A.

    2015-07-01

    The Fennec climate programme aims to improve understanding of the Saharan climate system through a synergy of observations and modelling. We present a description of the Fennec airborne observations during 2011 and 2012 over the remote Sahara (Mauritania and Mali) and the advances in the understanding of mineral dust and boundary layer processes they have provided. Aircraft instrumentation aboard the UK FAAM BAe146 and French SAFIRE (Service des Avions Français Instrumentés pour la Recherche en Environnement) Falcon 20 is described, with specific focus on instrumentation specially developed for and relevant to Saharan meteorology and dust. Flight locations, aims and associated meteorology are described. Examples and applications of aircraft measurements from the Fennec flights are presented, highlighting new scientific results delivered using a synergy of different instruments and aircraft. These include (1) the first airborne measurement of dust particles sizes of up to 300 microns and associated dust fluxes in the Saharan atmospheric boundary layer (SABL), (2) dust uplift from the breakdown of the nocturnal low-level jet before becoming visible in SEVIRI (Spinning Enhanced Visible Infra-Red Imager) satellite imagery, (3) vertical profiles of the unique vertical structure of turbulent fluxes in the SABL, (4) in situ observations of processes in SABL clouds showing dust acting as cloud condensation nuclei (CCN) and ice nuclei (IN) at -15 °C, (5) dual-aircraft observations of the SABL dynamics, thermodynamics and composition in the Saharan heat low region (SHL), (6) airborne observations of a dust storm associated with a cold pool (haboob) issued from deep convection over the Atlas Mountains, (7) the first airborne chemical composition measurements of dust in the SHL region with differing composition, sources (determined using Lagrangian backward trajectory calculations) and absorption properties between 2011 and 2012, (8) coincident ozone and dust surface area

  5. Dust, Climate, and Human Health

    NASA Astrophysics Data System (ADS)

    Maynard, N. G.

    2003-12-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. This paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health

  6. Dust, Climate, and Human Health

    NASA Technical Reports Server (NTRS)

    Maynard, Nancy G.

    2003-01-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. This paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health.

  7. Dust, Climate, and Human Health

    NASA Technical Reports Server (NTRS)

    Maynard, Nancy G.

    2003-01-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. Ths paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health.

  8. Lead, mercury, cadmium, chromium, nickel, copper, zinc, calcium, iron, manganese and chromium (VI) levels in Nigeria and United States of America cement dust.

    PubMed

    Ogunbileje, J O; Sadagoparamanujam, V-M; Anetor, J I; Farombi, E O; Akinosun, O M; Okorodudu, A O

    2013-03-01

    This study was aimed at investigating the relative abundance of heavy metals in cement dust from different cement dust factories in order to predict their possible roles in the severity of cement dust toxicity. The concentrations of total mercury (Hg), copper (Cu), chromium (Cr), cadmium (Cd), nickel (Ni), manganese (Mn), lead (Pb), iron (Fe) and chromium (VI) (Cr (VI)) levels in cement dust and clinker samples from Nigeria and cement dust sample from the United States of America (USA) were determined using graphite furnace atomic absorption (GFAAS), while Zn and Ca were measured by flame atomic absorption spectrophotometry (FAAS), and Cr (VI) by colorimetric method. Total Cu, Ni and Mn were significantly higher in cement dust sample from USA (p<0.05), also, both total Cr and Cr (VI) were 5.4-26 folds higher in USA cement dust compared with Nigeria cement dust or clinker (p<0.001). Total Cd was higher in both Nigeria cement dust and clinker (p<0.05 and p<0.001), respectively. Mercury was more in both Nigeria cement dust and clinker (p<0.05), while Pb was only significantly higher in clinker from Nigeria (p<0.001). These results show that cement dust contain mixture of metals that are known human carcinogens and also have been implicated in other debilitating health conditions. Additionally, it revealed that metal content concentrations are factory dependent. This study appears to indicate the need for additional human studies relating the toxicity of these metals and their health impacts on cement factory workers. PMID:23261125

  9. Ecosystem recharge by volcanic dust drives broad-scale variation in bird abundance.

    PubMed

    Gunnarsson, Tómas Grétar; Arnalds, Ólafur; Appleton, Graham; Méndez, Verónica; Gill, Jennifer A

    2015-06-01

    Across the globe, deserts and volcanic eruptions produce large volumes of atmospheric dust, and the amount of dust is predicted to increase with global warming. The effects of long-distance airborne dust inputs on ecosystem productivity are potentially far-reaching but have primarily been measured in soil and plants. Airborne dust could also drive distribution and abundance at higher trophic levels, but opportunities to explore these relationships are rare. Here we use Iceland's steep dust deposition gradients to assess the influence of dust on the distribution and abundance of internationally important ground-nesting bird populations. Surveys of the abundance of breeding birds at 729 locations throughout lowland Iceland were used to explore the influence of dust deposition on bird abundance in agricultural, dry, and wet habitats. Dust deposition had a strong positive effect on bird abundance across Iceland in dry and wet habitats, but not in agricultural land where nutrient levels are managed. The abundance of breeding waders, the dominant group of terrestrial birds in Iceland, tripled on average between the lowest and highest dust deposition classes in both wet and dry habitats. The deposition and redistribution of volcanic materials can have powerful impacts in terrestrial ecosystems and can be a major driver of the abundance of higher trophic-level organisms at broad spatial scales. The impacts of volcanic ash deposition during eruptions and subsequent redistribution of unstable volcanic materials are strong enough to override effects of underlying variation in organic matter and clay content on ecosystem fertility. Global rates of atmospheric dust deposition are likely to increase with increasing desertification and glacier retreat, and this study demonstrates that the effects on ecosystems are likely to be far-reaching, both in terms of spatial scales and ecosystem components. PMID:26120428

  10. Ecosystem recharge by volcanic dust drives broad-scale variation in bird abundance

    PubMed Central

    Gunnarsson, Tómas Grétar; Arnalds, Ólafur; Appleton, Graham; Méndez, Verónica; Gill, Jennifer A

    2015-01-01

    Across the globe, deserts and volcanic eruptions produce large volumes of atmospheric dust, and the amount of dust is predicted to increase with global warming. The effects of long-distance airborne dust inputs on ecosystem productivity are potentially far-reaching but have primarily been measured in soil and plants. Airborne dust could also drive distribution and abundance at higher trophic levels, but opportunities to explore these relationships are rare. Here we use Iceland's steep dust deposition gradients to assess the influence of dust on the distribution and abundance of internationally important ground-nesting bird populations. Surveys of the abundance of breeding birds at 729 locations throughout lowland Iceland were used to explore the influence of dust deposition on bird abundance in agricultural, dry, and wet habitats. Dust deposition had a strong positive effect on bird abundance across Iceland in dry and wet habitats, but not in agricultural land where nutrient levels are managed. The abundance of breeding waders, the dominant group of terrestrial birds in Iceland, tripled on average between the lowest and highest dust deposition classes in both wet and dry habitats. The deposition and redistribution of volcanic materials can have powerful impacts in terrestrial ecosystems and can be a major driver of the abundance of higher trophic-level organisms at broad spatial scales. The impacts of volcanic ash deposition during eruptions and subsequent redistribution of unstable volcanic materials are strong enough to override effects of underlying variation in organic matter and clay content on ecosystem fertility. Global rates of atmospheric dust deposition are likely to increase with increasing desertification and glacier retreat, and this study demonstrates that the effects on ecosystems are likely to be far-reaching, both in terms of spatial scales and ecosystem components. PMID:26120428

  11. Levels of polybrominated diphenyl ethers and novel flame retardants in microenvironment dust from Egypt: an assessment of human exposure.

    PubMed

    Hassan, Yasmeen; Shoeib, Tamer

    2015-02-01

    There are very few studies reporting concentrations of polybrominated diphenyl ethers (PBDEs) and novel flame retardants (FRs) or non-PBDEs in Africa and the Middle East. The present work reported concentrations of fourteen PBDE congeners and eleven non-PBDE flame retardants in dust samples collected from homes (n=17), workplaces (n=9) and cars (n=5) in the greater Cairo region. The median ∑PBDE concentrations were 57, 425 and 1608 ng g(-1) in homes, workplaces and cars respectively. The highest PBDE levels were observed for BDE 209, with a median concentration of 40.2, 366 and 1540 ng g(-1) representing 70% to 95% of the total PBDEs in homes, workplaces and cars respectively. This is about 8 to 46 times greater than the median concentration of the pentaBDE (represented by the most abundant compounds in this formulation, ∑BDE 47, 99 and 100). In the case of non-PBDE flame retardants, a detection frequency between 52% and 100% was observed for several compounds including: hexabromocyclododecane (HBCD), hexabromobenzene (HBB), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), bis (2-ethyl-1-hexyl) tetrabromophthalate (TBPH), 1,2-bis (2,4,6-tribromophenoxy) ethane (TBPE), ally-2,4,6-tribromophenyl ether (ATE) and Dechlorane Plus (DP). The ∑non-PBDE median concentrations were 8.30, 28.9 and 49.9 ng g(-1) in homes, workplaces and cars respectively with the highest level observed for HBCD in the three microenvironments. The detection of novel flame retardants in indoor environments may be due to their wide usage after the ban of the penta and octa BDE formulation. Results show the levels of PBDEs and non-PBDEs in Egyptian dust to be among the lowest levels reported from other countries. Different dust exposure scenarios using 5th percentile, median, 95th percentile and maximum levels were estimated for adult and children. The estimated dust intake results were several orders of magnitude lower than the oral reference dose values. PMID:25306095

  12. Enhancement of OVA-induced murine lung eosinophilia by co-exposure to contamination levels of LPS in Asian sand dust and heated dust

    PubMed Central

    2014-01-01

    Background A previous study has shown that the aggravation of Asian sand dust (ASD) on ovalbumin (OVA)-induced lung eosinphilia was more severe in lipopolysaccharide (LPS)-rich ASD than in SiO2-rich ASD. Therefore, the effects of different LPS contamination levels in ASD on the aggravation of OVA-induced lung eosinophilia were investigated in the present study. Methods Before beginning the in vivo experiment, we investigated whether the ultra-pure LPS would act only on TLR4 or not using bone marrow-derived macrophages (BMDMs) of wild–type, TLR2-/-, TLR4-/- and MyD88-/- BALB/c mice. ASD collected from the desert was heated to remove toxic organic substances (H-ASD). BALB/c mice were instilled intratracheally with 12 different testing samples prepared with LPS (1 ng and 10 ng), H-ASD, and OVA in a normal saline solution. The lung pathology, cytological profiles in the bronchoalveolar lavage fluid (BALF), the levels of inflammatory cytokines/chemokines in BALF and OVA-specific immunoglobulin in serum were investigated. Results The LPS exhibited no response to the production of TNF-α and IL-6 in BMDMs from TLR4-/-, but did from TLR2-/-. H-ASD aggravated the LPS-induced neutrophilic lung inflammation. In the presence of OVA, LPS increased the level of eosinophils slightly and induced trace levels of Th2 cytokines IL-5 and IL-13 at the levels of 1 ng and 10 ng. In the presence of OVA and H-ASD, LPS induced severe eosinophil infiltration and proliferation of goblet cells in the airways as well as remarkable increases in Th2 cytokines IL-5 and IL-13 in BALF. The mixture containing LPS (1 ng) showed adjuvant activity on OVA-specific IgE and IgG1 production. Conclusions The results suggest that H-ASD with naturally-occurring levels of LPS enhances OVA-induced lung eosinophilia via increases in Th2-mediated cytokines and antigen-specific immunoglobulin. These results indicate that LPS is a strong candidate for being a major aggravating substance in ASD. PMID:24982682

  13. Concentration and determinants of molds and allergens in indoor air and house dust of French dwellings.

    PubMed

    Dallongeville, Arnaud; Le Cann, Pierre; Zmirou-Navier, Denis; Chevrier, Cécile; Costet, Nathalie; Annesi-Maesano, Isabella; Blanchard, Olivier

    2015-12-01

    Molds and allergens are common indoor biocontaminants. The aims of this study were to assess the concentrations of common molds in indoor air and floor dust and the concentrations of house dust mite, cat and dog allergens in mattress dust in French dwellings, and to assess predictors of these concentrations. A sample of 150 houses in Brittany (western France) was investigated. Airborne Cladosporium and Penicillium were detected in more than 90% of the dwellings, Aspergillus in 46% and Alternaria in only 6% of the housings. Regarding floor dust samples, Cladosporium and Penicillium were detected in 92 and 80% of the housings respectively, Aspergillus in 49% and Alternaria in 14%. House dust mite allergens Der p1 and Der f1 were detected in 90% and 77% of the mattress dust samples respectively and Can f1 and Fel d1 in 37% and 89% of the homes. Airborne and dustborne mold concentrations, although not statistically correlated (except for Aspergillus) shared most of their predictors. Multivariate linear models for mold levels, explaining up to 62% of the variability, showed an influence of the season, of the age of the dwelling, of aeration habits, presence of pets, smoking, signals of dampness, temperature and relative humidity. Allergens in the dust of the mattress were strongly related to the presence of pets and cleaning practices of bedsheets, these factors accounting for 60% of the variability. This study highlights ubiquitous contamination by molds and underlines complex interaction between outdoor and indoor sources and factors. PMID:26094801

  14. New insight into the levels, distribution and health risk diagnosis of indoor and outdoor dust-bound FRs in colder, rural and industrial zones of Pakistan.

    PubMed

    Khan, Muhammad Usman; Li, Jun; Zhang, Gan; Malik, Riffat Naseem

    2016-09-01

    This is the first robust study designed to probe selected flame retardants (FRs) in the indoor and outdoor dust of industrial, rural and background zones of Pakistan with special emphasis upon their occurrence, distribution and associated health risk. For this purpose, we analyzed FRs such as polybrominated diphenylethers (PBDEs), dechlorane plus (DP), novel brominated flame retardants (NBFRs) and organophosphate flame retardants (OPFRs) in the total of 82 dust samples (indoor and outdoor) collected three from each zone: industrial, rural and background. We found higher concentrations of FRs (PBDEs, DP, NBFRs and OPFRs) in industrial zones as compared to the rural and background zones. Our results reveal that the concentrations of studied FRs are relatively higher in the indoor dust samples being compared with the outdoor dust and they are ranked as: ∑OPFRs > ∑NBFRs > ∑PBDEs > ∑DP. A significant correlation in the FRs levels between the indoor and outdoor dust suggest the potential intermixing of these compounds between them. The principal component analysis/multiple linear regression predicts the percent contribution of FRs from different consumer products in the indoor and outdoor dust of industrial, rural and background zones to trace their source origin. The FRs detected in the background zones reveal the dust-bound FRs suspended in the air might be shifted from different warmer zones or consumers products available/used in the same zones. Hazard quotient (HQ) for FRs via indoor and outdoor dust intake at mean and high dust scenarios to the exposed populations (adults and toddlers) are found free of risk (HQ < 1) in the target zones. Furthermore, our nascent results will provide a baseline record of FRs (PBDEs, DP, NBFRs and OPFRs) concentrations in the indoor and outdoor dust of Pakistan. PMID:27346442

  15. Dynamic Dust Accumulation and Dust Removal Observed on the Mars Exploration Rover Magnets

    NASA Technical Reports Server (NTRS)

    Bertelsen, P.; Bell, J. F., III; Goetz, W.; Gunnlaugsson, H. P.; Herkenhoff, K. E.; Hviid, S. F.; Johnson, J. R.; Kinch, K. M.; Knudsen, J. M.; Madsen, M. B.

    2005-01-01

    The Mars Exploration Rovers each carry a set of Magnetic Properties Experiments designed to investigate the properties of the airborne dust in the Martian atmosphere. It is a preferred interpretation of previous experiments that the airborne dust in the Martian atmosphere is primarily composed by composite silicate particles containing one or more highly magnetic minerals as a minor constituent. The ultimate goal of the magnetic properties experiments on the Mars Exploration Rover mission is to provide some information/ constraints on whether the dust is formed by volcanic, meteoritic, aqueous, or other processes. The first problem is to identify the magnetic mineral(s) in the airborne dust on Mars. While the overall results of the magnetic properties experiments are presented in, this abstract will focus on dust deposition and dust removal on some of the magnets.

  16. Conveyor dust control

    SciTech Connect

    Goldbeck, L.

    1999-11-01

    In the past, three different approaches have been used to control dust arising at conveyor load zones. They are: Dust Containment consists of those mechanical systems employed to keep material inside the transfer point with the main material body. Dust Suppression systems increase the mass of suspended dust particles, allowing them to fall from the air stream. Dust Collection is the mechanical capture and return of airborne material after it becomes airborne from the main material body. Previously, these three approaches have always been seen as separate entities. They were offered by separate organizations competing in the marketplace. The three technologies vied for their individual piece of the rock, at the expense of the other technologies (and often at the expense of overall success). There have been considerable amounts of I`m better selling, as well as finger pointing at the other systems when problems arose. Each system claimed its own technology was the best, providing the most effective, most cost-efficient, most maintenance-free solution to fugitive material.

  17. Variation in airborne 137Cs peak levels with altitude from high-altitude locations across Europe after the arrival of Fukushima-labeled air masses

    NASA Astrophysics Data System (ADS)

    Masson, Olivier; Bieringer, Jacqueline; Dalheimer, Axel; Estier, Sybille; Evrard, Olivier; Penev, Ilia; Ringer, Wolfgang; Schlosser, Clemens; Steinkopff, Thomas; Tositti, Laura; de Vismes-Ott, Anne

    2015-04-01

    During the Fukushima Daiichi nuclear power plant (FDNPP) accident, a dozen of high-altitude aerosol sampling stations, located between 850 and 3,454 m above sea level (a.s.l.), provided airborne activity levels across Europe (Fig. 1). This represents at most 5% of the total number of aerosol sampling locations that delivered airborne activity levels (at least one result) in Europe, in connection with this nuclear accident. High altitude stations are typically equipped with a high volume sampler that collects aerosols on filters. The Fukushima-labeled air mass arrival and the peak of airborne cesium-137 (137Cs) activity levels were registered in Europe at different dates depending on the location, with differences up to a factor of six on a regional scale. Besides this statement related to lowland areas, we have compared the maximum airborne levels registered at high-altitude European locations (850 m < altitudes < 3450 m) with what was observed at the closest lowland location. The vertical distribution of 137Cs peak level was not uniform even after a long travel time/distance from Japan. This being true at least in the atmospheric boundary layer and in the lower free troposphere. Moreover the relation '137Csmax vs. altitude' shows a decreasing trend (Fig. 2). Results and discussion : Comparison of 137Cs and 7Be levels shows simultaneous increases at least when the 137Cs airborne level rose for the first time (Fig. 3). Zugspitze and Jungfraujoch stations attest of a time shift between 7Be and 137Cs peak that can be due to the particular dynamic of air movements at such high altitudes. After the 137Cs peak value, the plume concentration decreased whatever the 7Be level. Due to the cosmogenic origin of 7Be, its increase in the ground-level air is usually associated with downwind air movements, i.e. stratospheric air intrusions or at least air from high-tropospheric levels, into lower atmospheric layers. This means that Fukushima-labeled air masses registered at ground

  18. Occupational Exposure to Crystalline Silica Dust in the United States, 1988–2003

    PubMed Central

    Yassin, Abdiaziz; Yebesi, Francis; Tingle, Rex

    2005-01-01

    The purposes of this study were a) to summarize measurements of airborne (respirable) crystalline silica dust exposure levels among U.S. workers, b) to provide an update of the 1990 Stewart and Rice report on airborne silica exposure levels in high-risk industries and occupations with data for the time period 1988–2003, c) to estimate the number of workers potentially exposed to silica in industries that the Occupational Safety and Health Administration (OSHA) inspected for high exposure levels, and d) to conduct time trend analyses on airborne silica dust exposure levels for time-weighted average (TWA) measurements. Compliance inspection data that were taken from the OSHA Integrated Management Information System (IMIS) for 1988–2003 (n = 7,209) were used to measure the airborne crystalline silica dust exposure levels among U.S. workers. A second-order autoregressive model was applied to assess the change in the mean silica exposure measurements over time. The overall geometric mean of silica exposure levels for 8-hr personal TWA samples collected during programmed inspections was 0.077 mg/m3, well above the applicable American Conference of Governmental Industrial Hygienists threshold limit value of 0.05 mg/m3. Surgical appliances supplies industry [Standard Industrial Classification (SIC) 3842] had the lowest geometric mean silica exposure level of 0.017 mg/m3, compared with the highest level, 0.166 mg/m3, for the metal valves and pipe fitting industry (SIC 3494), for an 8-hr TWA measurement. Although a downward trend in the airborne silica exposure levels was observed during 1988–2003, the results showed that 3.6% of the sampled workers were exposed above the OSHA-calculated permissible exposure limit. PMID:15743711

  19. Evaluation of HEPA vacuum cleaning and dry steam cleaning in reducing levels of polycyclic aromatic hydrocarbons and house dust mite allergens in carpets

    PubMed Central

    Yu, Chang Ho; Yiin, Lih-Ming; Fan, Zhi-Hua (Tina); Rhoads, George G.

    2014-01-01

    Dry steam cleaning, which has gained recent attention as an effective method to reduce house dust mite (HDM) allergen concentration and loading in carpets, was evaluated in this study for its efficacy in lowering levels of polycyclic aromatic hydrocarbons (PAHs) as well as HDM allergens. Fifty urban homes with wail-to-wall carpets, mostly low-income and with known lead contamination, were studied in 2003 and 2004. Two carpet-cleaning interventions were compared: Repeated HEPA (High Efficiency Particulate Air filtered) vacuuming alone and repeated HEPA vacuuming supplemented with dry steam cleaning. Vacuum samples were collected to measure carpet loading of dust and contaminants immediately before and after cleaning. Paired comparisons were conducted to evaluate the effectiveness of the cleaning protocols in reducing the levels of PAHs and HDM allergens in carpets. The results indicated that both cleaning methods substantially reduced the loading of PAHs and HDM allergens as well as dust in carpets (p < 0.0001). The reductions in loading of dust (64.4%), PAHs (69.1%), and HDM allergens (85.5%), by dry steam cleaning plus repetitive HEPA vacuuming were larger than the reductions by regular HEPA vacuuming alone: dust (55.5%), PAHs (58.6%), and HDM allergens (80.8%), although the difference was statistically significant only for dust and PAHs. We conclude that intensive HEPA vacuum cleaning substantially reduced the loading of PAHs and HDM allergens in carpets in these urban homes and that dry steam cleaning added modestly to cleaning effectiveness. PMID:19137159

  20. Evaluation of HEPA vacuum cleaning and dry steam cleaning in reducing levels of polycyclic aromatic hydrocarbons and house dust mite allergens in carpets.

    PubMed

    Yu, Chang Ho; Yiin, Lih-Ming; Tina Fan, Zhi-Hua; Rhoads, George G

    2009-01-01

    Dry steam cleaning, which has gained recent attention as an effective method to reduce house dust mite (HDM) allergen concentration and loading in carpets, was evaluated in this study for its efficacy in lowering levels of polycyclic aromatic hydrocarbons (PAHs) as well as HDM allergens. Fifty urban homes with wall-to-wall carpets, mostly low-income and with known lead contamination, were studied in 2003 and 2004. Two carpet-cleaning interventions were compared: Repeated HEPA (High Efficiency Particulate Air filtered) vacuuming alone and repeated HEPA vacuuming supplemented with dry steam cleaning. Vacuum samples were collected to measure carpet loading of dust and contaminants immediately before and after cleaning. Paired comparisons were conducted to evaluate the effectiveness of the cleaning protocols in reducing the levels of PAHs and HDM allergens in carpets. The results indicated that both cleaning methods substantially reduced the loading of PAHs and HDM allergens as well as dust in carpets (p < 0.0001). The reductions in loading of dust (64.4%), PAHs (69.1%), and HDM allergens (85.5%), by dry steam cleaning plus repetitive HEPA vacuuming were larger than the reductions by regular HEPA vacuuming alone: dust (55.5%), PAHs (58.6%), and HDM allergens (80.8%), although the difference was statistically significant only for dust and PAHs. We conclude that intensive HEPA vacuum cleaning substantially reduced the loading of PAHs and HDM allergens in carpets in these urban homes and that dry steam cleaning added modestly to cleaning effectiveness. PMID:19137159

  1. A method for computing the damage level due to the exposure to an airborne chemical with a time-varying concentration.

    PubMed

    Acquesta, Alejandro D; Sánchez, Erica Yanina; Porta, Andres; Jacovkis, Pablo M

    2011-09-01

    The calculation of damage level due to the exposure to a toxic cloud is usually not included in most popular software, or it is included using techniques that do not take into account the variation in concentration over a period of time. In this work, a method is introduced for calculating the temporal evolution of the potential damage level and to obtain a more precise and descriptive estimation of this level. The proposed goal is: to estimate the maximum and minimum damage level experienced by a population due to the exposure to an airborne chemical with a time-varying concentration; to be able to assess the damage level experienced in a progressive way, as the exposure to the airborne chemical occurs. The method relies on transformations of time-concentration pairs on a continuum of damage level curves based on the available guideline levels, obtaining maximum and minimum approximations of the expected damage level for any exposure duration. Consequently, applying this method to transport model output data and demographic information, damage evolution in relation to time and space can be predicted, as well as its effect on the local population, which enables the determination of threat zones. The comparison between the proposed method and the current (Spanish and ALOHA) ones showed that the former can offer a more precise estimation and a more descriptive approach of the potential damage level. This method can be used by atmospheric dispersion models to compute damage level and graphically display the regions exposed to each guideline level on area maps. PMID:21395635

  2. Characteristics of the east Mediterranean dust variability on small spatial and temporal scales

    NASA Astrophysics Data System (ADS)

    Yuval; Sorek-Hamer, Meytar; Stupp, Amnon; Alpert, Pinhas; Broday, David M.

    2015-11-01

    The presence of naturally-occurring dust is a conspicuous meteorological phenomenon characterised by very high load of relatively coarse airborne particulate matter (PM), which may contain also various deleterious chemical and biological materials. Much work has been carried out to study the phenomenon by modelling the generation and transport of dust plumes, and assessment of their temporal characteristics on a large (>1000 km) spatial scale. This work studies in high spatial and temporal resolution the characteristics of dust presence on the mesoscale (>100 km). The small scale variability is important both for better understanding the physical characteristics of the dust phenomenon and for PM exposure specification in epidemiological studies. Unsupervised clustering-based method, using PM10 records and their derived attributes, was developed and applied to detect the impact of dust at the observation locations of a PM10 monitoring array. It was found that dust may cover the whole study area but very often the coverage is partial. On average, the larger the spatial extent of a dust event, the higher and more homogeneous are the associated PM10 concentrations. Dust event lengths however, are only weakly associated with the PM concentrations (Pearson correlation below 0.44). The large PM concentration variability during spatially small events and the fact that their occurrence is strongly correlated with the elevation above sea level of the reporting stations (Pearson correlation 0.87, p-value < 10-5) points to small scale spatiotemporal dynamics of dust plumes.

  3. Improve dust capture on your surface drill

    SciTech Connect

    Page, S.J.; Listak, J.M.; Reed, R.

    2008-09-15

    Researchers have developed a model to describe airborne respirable dust (ARD) generation on surface coal mine drills. By measuring a few basic parameters and using a graph, a drill operator or engineer can estimate the relative severity of drill dust emissions as well as how much of a reduction in ARD can be obtained by changing any given parameter. 4 refs., 2 figs.

  4. Retrieval of effective leaf area index (LAIe) and leaf area density (LAD) profile at individual tree level using high density multi-return airborne LiDAR

    NASA Astrophysics Data System (ADS)

    Lin, Yi; West, Geoff

    2016-08-01

    As an important canopy structure indicator, leaf area index (LAI) proved to be of considerable implications for forest ecosystem and ecological studies, and efficient techniques for accurate LAI acquisitions have long been highlighted. Airborne light detection and ranging (LiDAR), often termed as airborne laser scanning (ALS), once was extensively investigated for this task but showed limited performance due to its low sampling density. Now, ALS systems exhibit more competing capacities such as high density and multi-return sampling, and hence, people began to ask the questions like-"can ALS now work better on the task of LAI prediction?" As a re-examination, this study investigated the feasibility of LAI retrievals at the individual tree level based on high density and multi-return ALS, by directly considering the vertical distributions of laser points lying within each tree crown instead of by proposing feature variables such as quantiles involving laser point distribution modes at the plot level. The examination was operated in the case of four tree species (i.e. Picea abies, Pinus sylvestris, Populus tremula and Quercus robur) in a mixed forest, with their LAI-related reference data collected by using static terrestrial laser scanning (TLS). In light of the differences between ALS- and TLS-based LAI characterizations, the methods of voxelization of 3D scattered laser points, effective LAI (LAIe) that does not distinguish branches from canopies and unified cumulative LAI (ucLAI) that is often used to characterize the vertical profiles of crown leaf area densities (LADs) was used; then, the relationships between the ALS- and TLS-derived LAIes were determined, and so did ucLAIs. Tests indicated that the tree-level LAIes for the four tree species can be estimated based on the used airborne LiDAR (R2 = 0.07, 0.26, 0.43 and 0.21, respectively) and their ucLAIs can also be derived. Overall, this study has validated the usage of the contemporary high density multi

  5. Impacts of Asian dust events on atmospheric fungal communities

    NASA Astrophysics Data System (ADS)

    Jeon, Eun Mi; Kim, Yong Pyo; Jeong, Kweon; Kim, Ik Soo; Eom, Suk Won; Choi, Young Zoo; Ka, Jong-Ok

    2013-12-01

    The composition of atmospheric fungi in Seoul during Asian dust events were assessed by culturing and by molecular methods such as mold specific quantitative PCR (MSQPCR) and internal transcribed spacer cloning (ITS cloning). Culturable fungal concentrations in the air were monitored from May 2008 to July 2011 and 3 pairs of ITS clone libraries, one during Asian dust (AD) day and the other during the adjacent non Asian dust (NAD) day for each pair, were constructed after direct DNA extraction from total suspended particles (TSP) samples. In addition, six aeroallergenic fungi in the atmosphere were also assessed by MSQPCR from October, 2009 to November, 2011. The levels of the airborne culturable fungal concentrations during AD days was significantly higher than that of NAD days (P < 0.005). In addition, the correlation of culturable fungal concentrations with particulate matters equal to or less than 10 μm in aerodynamic diameter (PM10) concentrations was observed to be high (0.775) for the AD days while correlation coefficients of PM10 as well as other particulate parameters with airborne fungal concentrations were significantly negative for the NAD days during intensive monitoring periods (May to June, 2008). It was found that during AD days several airborne allergenic fungal levels measured with MSQPCR increased up to 5-12 times depending on the species. Comparison of AD vs. NAD clones showed significant differences (P < 0.05) in all three cases using libshuff. In addition, high proportions of uncultured soil fungus isolated from semi-arid regions were observed only in AD clone libraries. Thus, it was concluded that AD impacts not only airborne fungal concentrations but also fungal communities.

  6. Identification of anthropogenic and natural dust sources using Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue level 2 data

    NASA Astrophysics Data System (ADS)

    Ginoux, Paul; Garbuzov, Dmitri; Hsu, N. Christina

    2010-03-01

    Mineral dust interacts with radiation and impacts both the regional and global climate. The relative contribution of natural and anthropogenic dust sources, however, remains largely uncertain. Although human activities disturb soils and therefore enhance wind erosion, their contribution to global dust emission has never been directly evaluated because of a lack of data. The retrieval of aerosol properties over land, including deserts, using the Moderate Resolution Imaging Spectroradiometer Deep Blue algorithm makes the first direct characterization of the origin of individual sources possible. In order to separate freshly emitted dust from other aerosol types and aged dust particles, the spectral dependence of the single scattering albedo and the Angstrom wavelength exponent are used. Four years of data from the eastern part of West Africa, which includes one of the most active natural dust sources and the highest population density on the continent, are processed. Sources are identified on the basis of the persistence of significant aerosol optical depth from freshly emitted dust, and the origin is characterized as natural or anthropogenic on the basis of a land use data set. Our results indicate that although anthropogenic dust is observed less frequently and with lower optical depth than dust from natural sources in this particular region, it occupies a large area covering most of northern Nigeria and southern Chad, around Lake Chad. In addition, smaller anthropogenic sources are found as far south as 5° of latitude north, well outside the domain of most dust source inventories.

  7. Reducing Coal Dust With Water Jets

    NASA Technical Reports Server (NTRS)

    Gangal, M. D.; Lewis, E. V.

    1985-01-01

    Jets also cool and clean cutting equipment. Modular pick-and-bucket miner suffers from disadvantage: Creates large quantities of potentially explosive coal dust. Dust clogs drive chain and other parts and must be removed by hand. Picks and bucket lips become overheated by friction and be resharpened or replaced frequently. Addition of oscillating and rotating water jets to pick-and-bucket machine keeps down dust, cools cutting edges, and flushes machine. Rotating jets wash dust away from drive chain. Oscillating jets cool cutting surfaces. Both types of jet wet airborne coal dust; it precipitates.

  8. Quantifying Airborne Allergen Levels Before and After Rain Events Using TRMM/GPM and Ground-Sampled Data

    NASA Technical Reports Server (NTRS)

    Stewart, Randy M.

    2006-01-01

    Allergies affect millions of Americans, increasing health risks and also increasing absenteeism and reducing productivity in the workplace. Outdoor allergens, such as airborne pollens and mold spores, commonly trigger respiratory distress symptoms, but rainfall reduces the quantity of allergens in the air (EPA, 2003). The current NASA Tropical Rainfall Measuring Mission provides accurate information related to rain events. These capabilities will be further enhanced with the future Global Precipitation Measurement mission. This report examines the effectiveness of combining these NASA resources with established ground-based allergen/spore sampling systems to better understand the benefits that rain provides in removing allergens and spores from the air.

  9. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the workshop was on how the airborne community can assist in achieving the goals of the Global Change Research Program. The many activities that employ airborne platforms and sensors were discussed: platforms and instrument development; airborne oceanography; lidar research; SAR measurements; Doppler radar; laser measurements; cloud physics; airborne experiments; airborne microwave measurements; and airborne data collection.

  10. New techniques for spraying dust

    SciTech Connect

    Mukherjee, S.K.

    1984-06-01

    Two recent developments for reducing airborne dust on longwall faces are described. One flushes foam through the drums of a shearer and also sprays foam onto the cutting drum. The other modifies the spray-head to produce different water spray patterns on continuous miners.

  11. Airborne laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven E.

    2002-06-01

    The US Air Force Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the risk reduction approach being utilized to ensure program success.

  12. WMO Sand and Dust Storm Warning Advisory and Assessment System (SDS-WAS): Research Implementation Status

    NASA Astrophysics Data System (ADS)

    Nickovic, Slobodan; Barrie, Leonard

    2010-05-01

    Assessment System (SDS-WAS) in order to improve the capabilities of countries affected by dust to reduce risks associated with airborne sand and dust. This project is in response to the desire of more than 40 WMO member countries to improve capabilities for more reliable sand and dust storm forecasts. The project has strong crosscutting features: it relies on real-time delivery of products; it integrates research communities (modelling, observation groups, and effects) and communities of practice (e.g. medical, aeronautical, agricultural users). There are two already established SDS-WAS nodes (Asian and North-Africa-Europe-Middle East) that coordinate implementation of the project objectives at regional levels. This presentation will review current status and future steps in the project implementation.

  13. Hebes Chasma Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches are located in Hebes Chasma.

    Image information: VIS instrument. Latitude -1.4, Longitude 286.6 East (73.4 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  14. Association between first airborne cedar pollen level peak and pollinosis symptom onset: a web-based survey.

    PubMed

    Bando, Harumi; Sugiura, Hiroaki; Ohkusa, Yasushi; Akahane, Manabu; Sano, Tomomi; Jojima, Noriko; Okabe, Nobuhiko; Imamura, Tomoaki

    2015-01-01

    Cedar pollinosis in Japan affects nearly 25 % of Japanese citizens. To develop a treatment for cedar pollinosis, it is necessary to understand the relationship between the time of its occurrence and the amount of airborne cedar pollen. In the spring of 2009, we conducted daily Internet-based epidemiologic surveys, which included 1453 individuals. We examined the relationship between initial date of onset of pollinosis symptoms and daily amount of airborne cedar pollen to which subjects were exposed. Approximately 35.2 % of the subjects experienced the onset of pollinosis during a one-week interval in which the middle day coincided with the peak pollen count. The odds ratio for this one-week time interval was 4.03 (95 % confidence interval: 3.34-4.86). The predicted date of the cedar pollen peak can be used to determine the appropriate date for initiation of self-medication with anti-allergy drugs and thus avoid development of sustained and severe pollinosis. PMID:24720339

  15. A systems level characterization and tradespace evaluation of a simulated airborne Fourier transform infrared spectrometer for gas detection

    NASA Astrophysics Data System (ADS)

    Weiner, Aaron

    The remote sensing gas detection problem is one with no straightforward solution. While success has been achieved in detecting and identifying gases released from industrial stacks and other large plumes, the fugitive gas detection problem is far more complex. Fugitive gas represents a far smaller target and may be generated by leaking pipes, vents, or small scale chemical production. The nature of fugitive gas emission is such that one has no foreknowledge of the location, quantity, or transient rate of the targeted effluent which requires one to cover a broad area with high sensitivity. In such a scenario, a mobile airborne platform would be a likely candidate. Further, the spectrometer used for gas detection should be capable of rapid scan rates to prevent spatial and spectral smearing, while maintaining high resolution to aid in species identification. Often, insufficient signal to noise (SNR) prevents spectrometers from delivering useful results under such conditions. While common dispersive element spectrometers (DES) suffer from decreasing SNR with increasing spectral dispersion, Fourier Transform Spectrometers (FTS) generally do not and would seemingly be an ideal choice for such an application. FTS are ubiquitous in chemical laboratories and in use as ground based spectrometers, but have not become as pervasive in mobile applications. While FTS spectrometers would otherwise be ideal for high resolution rapid scanning in search of gaseous effluents, when conducted via a mobile platform the process of optical interferogram formation to form spectra is corrupted when the input signal is temporally unstable. This work seeks to explore the tradespace of an airborne Michelson based FTS in terms of modeling and characterizing the performance degradation over a variety of environmental and optical parameters. The major variables modeled and examined include: maximum optical path distance (resolution), scan rate, platform velocity, altitude, atmospheric and

  16. Levels and profile of several classes of organic contaminants in matched indoor dust and serum samples from occupational settings of Pakistan.

    PubMed

    Ali, Nadeem; Mehdi, Toufeer; Malik, Riffat N; Eqani, Syed A M A S; Kamal, Atif; Dirtu, Alin C; Neels, Hugo; Covaci, Adrian

    2014-10-01

    Dust ingestion is an important route of human exposure to organic contaminants, especially for flame retardants (FRs) in occupational settings. Several classes of organic contaminants were analyzed in matched dust and serum samples from academics and workers in electronics and clothing stores of Faisalabad, Pakistan. The concentrations of contaminants varied in dust as follow: organophosphate FRs (∑PFRs) > novel brominated FRs (∑NBFRs) > polybrominated diphenyl ethers (∑PBDEs) > organochlorine pesticides (∑OCPs) > polychlorinated biphenyls (∑PCBs), while, in serum, concentration varied: ∑OCPs > bromophenols (∑BPs) > ∑PCBs > ∑HO-PCBs ≈ ∑PBDEs. Two NBFRs, namely 1,2-bis(2,4,6-tribromophenoxy)-ethane (BTBPE) and bis(2-ethylhexyl) tetrabromophthalate (TBPH), were detected in <10% of the serum samples. p,p'-DDE was the major contaminant in serum contributing to ∼75% of the total contaminant burden. Levels of Penta-BDE congeners in serum and dust were significantly correlated (r = 0.64, p < 0.01) for the academics, suggesting dust ingestion as an important determinant for their serum levels. PMID:25069086

  17. Overview of Dust Model Inter-comparison (DMIP) in East Asia

    NASA Astrophysics Data System (ADS)

    Uno, I.

    2004-12-01

    Dust transport modeling plays an important role in understanding the recent increase of Asian Dust episodes and its impact to the regional climate system. Several dust models have been developed in several research institutes and government agencies independently since 1990s. Their numerical results either look very similar or different. Those disagreements are caused by difference in dust modules (concepts and basic mechanisms) and atmospheric models (meteorological and transport models). Therefore common understanding of performance and uncertainty of dust erosion and transport models in the Asian region becomes very important. To have a better understanding of dust model application, we proposed the dust model intercomparison under the international cooperation networks as a part of activity of ADEC (Aeolian Dust Experiment on Climate Impact) project research. Current participants are Kyusyu Univ. (Japan), Meteorological Research Institute (Japan), Hong-Kong City Univ. (China), Korean Meteorological Agency METRI (Korea), US Naval Research Laboratory (USA), Chinese Meteorological Agency (China), Institute of Atmospheric Physics (China), Insular Coastal Dynamics (Malta) and Meteorological Service of Canada (Canada). As a case study episode, we set two huge dust storms occurred in March and April 2002. Results from the dust transport model from all the participants are compiled on the same methods and examined the model characteristics against the ground and airborne measurement data. We will also examine the dust model results from the horizontal distribution at specified levels, vertical profiles, concentration at special check point and emission flux at source region, and show the important parameters for dust modeling. In this paper, we will introduce the general overview of this DMIP activity and several important conclusions from this activity.

  18. Effects of quartz, airborne particulates and fly ash fractions from a waste incinerator on elastase release by activated and nonactivated rabbit alveolar macrophages

    SciTech Connect

    Gulyas, H.; Labedzka, M.; Schmidt, N.; Gercken, G.

    1988-01-01

    Elastase release from cultured, activated and nonactivated rabbit alveolar macrophages (AM) was investigated after stimulation by different environmentally related mineral dusts (50-1000 micrograms/10(6) cells). Eight different dusts were analyzed for element contents and grain size: one rural and three urban airborne dusts, a coarse and a fine fraction of a sieved waste incinerator fly ash, a sonicated coarse fly ash fraction, and the standard quartz dust DQ 12. The fine fly ash fraction, the sonicated coarse fly ash fraction, and the quartz dust DQ 12 enhanced elastase release by activated AM. Only one of the tested airborne dusts effected a comparable elastase release. The untreated coarse fraction of the fly ash did not cause a significant increase of extracellular elastase activities. Elastase release was dependent on particle numbers and chemical composition and correlated best with barium and tin contents. Nonactivated AM released higher elastase activities than activated AM at low-dose levels. The possible role of dust-induced elastase secretion in the pathogenesis of emphysema is discussed.

  19. Dust storm off Western Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The impacts of Saharan dust storms reach far beyond Africa. Wind-swept deserts spill airborne dust particles out over the Atlantic Ocean where they can enter trade winds bound for Central and North America and the Caribbean. This Moderate Resolution Imaging Spectroradiometer (MODIS) image shows a dust storm casting an opaque cloud of cloud across the Canary Islands and the Atlantic Ocean west of Africa on June 30, 2002. In general it takes between 5 and 7 days for such an event to cross the Atlantic. The dust has been shown to introduce foreign bacteria and fungi that have damaged reef ecosystems and have even been hypothesized as a cause of increasing occurrences of respiratory complaints in places like Florida, where the amount of Saharan dust reaching the state has been increasing over the past 25 years.

  20. Dust and the Dust Bowl: Connections between 1930's drought and dust

    NASA Astrophysics Data System (ADS)

    O'Brien, T. A.; Sloan, L. C.; Solmon, F.; Snyder, M. A.

    2007-12-01

    There have been a number of investigations into the causes and physical mechanisms of the 1930's Dust Bowl, and together they provide a reasonable explanation of the drought in terms of its length and severity. However no published investigations have considered the possible climatic effects caused by the considerable amount of airborne dust that was generated as a consequence of poor land use management in the late 19th and early 20th centuries. In order to investigate the effects of airborne dust on North American climate during the 1930's, we have performed a climate model sensitivity study that isolates the effects of dust on climate in a regional climate model. The results of the study show that an essentially permanent dust cloud existed over North America through the duration of the drought. The dust cloud, which we show was quite thick over its center in the Midwest, blocked enough solar radiation to reduce surface temperatures by about 1 K. In addition, we show that a complex feedback between dust and drought caused a spatial redistribution of precipitation, in which various regions gained or lost an average of about 1 mm/day of precipitation.

  1. Levels of Non-Polybrominated Diphenyl Ether Brominated Flame Retardants in Residential House Dust Samples and Fire Station Dust Samples in California

    PubMed Central

    Brown, F Reber; Whitehead, Todd P; Park, June-Soo; Metayer, Catherine; Petreas, Myrto X

    2014-01-01

    Eleven novel brominated flame retardants (NBFRs) were analyzed in dust samples from California homes as a part of the Northern California Childhood Leukemia Study (NCCLS) and from the living quarters of California fire stations as a part of the Firefighter Occupational Exposure (FOX) study using high resolution gas chromatography/mass spectrometry. The eleven NBFRs, were: α- and β-1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (α- and β-DBE-DBCH), 2-bromoallyl 2,3,6-tribromophenylether (BATE), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB), 2,3-dibromopropyl 2,4,6-tribromophenyl ether (TBP-DBPE), hexabromobenzene (HBB), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP), and decabromodiphenylethane (DBDPE). Six of the seven NBFRs that are produced in relatively small quantities (i.e., α−, β−DBE-DBCH, BATE, PBEB, PBT, TBP-DBPE) were measured close to or below the limit of quantitation (0.64 ng/g) in both the NCCLS and FOX samples, and the seventh, HBB, was measured at median concentrations of 1.85 ng/g and 9.40 ng/g in the NCCLS and FOX samples, respectively. The remaining four NBFRs, EH-TBB, BEH-TEBP, BTBPE, and DBDPE, are produced in higher quantities, and were detected at median concentrations of 337 ng/g, 186 ng/g, 22.3, ng/g, and 82.8 ng/g, respectively in the NCCLS samples, and at median concentrations of 2687 ng/g, 2076 ng/g, 28.4 ng/g, and 161 ng/g, respectively, in the FOX samples. Concentrations of NBFRs in the NCCLS and FOX dust samples were several times lower than concentrations of PBDEs previously measured in the same samples. Concentrations of NBFRs in the NCCLS and FOX dust samples were generally comparable to concentrations of NBFRs in other studies of house dust from the US and Canada. PMID:25261858

  2. Levels of non-polybrominated diphenyl ether brominated flame retardants in residential house dust samples and fire station dust samples in California.

    PubMed

    Brown, F Reber; Whitehead, Todd P; Park, June-Soo; Metayer, Catherine; Petreas, Myrto X

    2014-11-01

    Eleven novel brominated flame retardants (NBFRs) were analyzed in dust samples from California homes as a part of the Northern California Childhood Leukemia Study (NCCLS) and from the living quarters of California fire stations as a part of the Firefighter Occupational Exposure (FOX) study using high resolution gas chromatography/mass spectrometry. The eleven NBFRs were α- and β-1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (α- and β-DBE-DBCH), 2-bromoallyl 2,3,6-tribromophenylether (BATE), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB), 2,3-dibromopropyl 2,4,6-tribromophenyl ether (TBP-DBPE), hexabromobenzene (HBB), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP), and decabromodiphenylethane (DBDPE). Six of the seven NBFRs that are produced in relatively small quantities (i.e., α-, β-DBE-DBCH, BATE, PBEB, PBT, TBP-DBPE) were measured close to or below the limit of quantitation (0.64 ng/g) in both the NCCLS and FOX samples, and the seventh, HBB, was measured at median concentrations of 1.85 ng/g and 9.40 ng/g in the NCCLS and FOX samples, respectively. The remaining four NBFRs, EH-TBB, BEH-TEBP, BTBPE, and DBDPE, are produced in higher quantities, and were detected at median concentrations of 337 ng/g, 186 ng/g, 22.3 ng/g, and 82.8 ng/g, respectively in the NCCLS samples, and at median concentrations of 2687 ng/g, 2076 ng/g, 28.4 ng/g, and 161 ng/g, respectively, in the FOX samples. Concentrations of NBFRs in the NCCLS and FOX dust samples were several times lower than concentrations of PBDEs previously measured in the same samples. Concentrations of NBFRs in the NCCLS and FOX dust samples were generally comparable to concentrations of NBFRs in other studies of house dust from the US and Canada. PMID:25261858

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

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

  4. Size distribution and optical properties of mineral dust aerosols transported in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Cassola, F.; Mazzino, A.; Triquet, S.; Chevaillier, S.; Grand, N.; Bourrianne, T.; Momboisse, G.; Sellegri, K.; Schwarzenbock, A.; Freney, E.; Mallet, M.; Formenti, P.

    2016-02-01

    This study presents in situ aircraft measurements of Saharan mineral dust transported over the western Mediterranean basin in June-July 2013 during the ChArMEx/ADRIMED (the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) airborne campaign. Dust events differing in terms of source region (Algeria, Tunisia and Morocco), time of transport (1-5 days) and height of transport were sampled. Mineral dust were transported above the marine boundary layer, which conversely was dominated by pollution and marine aerosols. The dust vertical structure was extremely variable and characterized by either a single layer or a more complex and stratified structure with layers originating from different source regions. Mixing of mineral dust with pollution particles was observed depending on the height of transport of the dust layers. Dust layers carried a higher concentration of pollution particles below 3 km above sea level (a.s.l.) than above 3 km a.s.l., resulting in a scattering Ångström exponent up to 2.2 below 3 km a.s.l. However, the optical properties of the dust plumes remained practically unchanged with respect to values previously measured over source regions, regardless of the altitude. Moderate absorption of light by the dust plumes was observed with values of aerosol single scattering albedo at 530 nm ranging from 0.90 to 1.00. Concurrent calculations from the aerosol chemical composition revealed a negligible contribution of pollution particles to the absorption properties of the dust plumes that was due to a low contribution of refractory black carbon in regards to the fraction of dust and sulfate particles. This suggests that, even in the presence of moderate pollution, likely a persistent feature in the Mediterranean, the optical properties of the dust plumes could be assumed similar to those of native dust in radiative transfer simulations, modelling studies and satellite retrievals

  5. Increased levels of ambient fungal spores in Taiwan are associated with dust events from China

    NASA Astrophysics Data System (ADS)

    Wu, Pei-Chih; Tsai, Jui-Chen; Li, Fang-Chun; Lung, Shih-Chun; Su, Huey-Jen

    2004-09-01

    Fungi are ubiquitous in nature and their spores are often dispersed into the atmosphere through turbulent airstreams. As yellow sandstorm blown from deserts in China had affected the ambient air quality with increasing levels of ambient particulates, often including significant amounts of biologically active particles has therefore become imperative for concerns of their health implications. Our study was aimed to examine the effects of yellow sandstorm events on the fungal composition and concentrations in ambient air. Atmospheric fungal spores were continuously collected using Burkard Volumetric Spore Trap. Samples collected between December 2000 and April 2001 were selected for priority analysis from days when the yellow sandstorms were reported to affect Taiwan according to the Central Weather Bureau in Taiwan. The composition of dominant spores such as Basidiospore, Penicillium/Aspergillus, Nigrospora, Arthrinium, Curvularia, Rusts, Stemphylium, Cercospora, Pithomyces, and unidentified fungi were significantly higher than those of background days. The increase of Basidiospore, Penicillium/Aspergillus, Nigrospora, and those unidentified fungi seems to be significantly associated with the increase of ambient particulate levels with regression coefficients ranging from 0.887 to 31.98. Our study has identified increasing ambient concentrations during sandstorm episodes are observed for some major fungi, Basidiospore, Penicillium, Aspergillus, and those unidentified fungi and the trends of the increase seems to associate with ambient particulate levels. Further efforts to clarify the relationship between those high fungal spore exposures and clinical adverse health effects are suggested in the future. In addition, effects of climatic factors and other particulate levels on the variation of ambient fungal spore levels are also desired in further study. Additional monitoring of ambient fungal spores in the first line of west coastline is hoped to assist in

  6. Simulation of the Radiative Impact of High Dust Loading during a Dust Storm in March 2012

    NASA Astrophysics Data System (ADS)

    Puthan Purakkal, J.; Kalenderski, S.; Stenchikov, G. L.

    2013-12-01

    We investigated a severe dust storm that developed over vast areas of the Middle East on 18-19 March 2012 and affected Saudi Arabia, Sudan, Egypt, Jordan, United Arab Emirates, Bahrain, Qatar, Oman, Kuwait, Iraq, Iran, Israel, and Pakistan. The visible aerosol optical depth recorded by the AERONET station on the KAUST campus (22.30o N 39.10o E) during the storm reached 4.5, exceeding the average level by an order of magnitude. To quantify the effects of the dust on atmospheric radiation and dynamics, we analyzed available ground-based and satellite observations and conducted numerical simulations using a fully coupled meteorology-chemistry-aerosol model (WRF-Chem). The model was able to reproduce the spatial and temporal patterns of the aerosol optical depths (AOD) observed by airborne and ground-based instruments. The major dust sources included river valleys of lower Tigris and Euphrates in Iraq, desert areas in Kuwait, Iran, United Arab Emirates, central Arabia including Rub' al Khali, An Nafud, and Ad Dahna, as well as the Red Sea coast of the Arabian Peninsula. The total amount of dust generated across the entire domain during the period of the simulation reached 93.76 Mt; 73.04 Mt of dust was deposited within the domain; 6.56 Mt of dust sunk in the adjacent sea waters, including 1.20 Mt that sedimented into the Red Sea. The model predicted a well-mixed boundary layer expanding up to 3.5 km in the afternoon. Some dust plumes were seen above the Planetary Boundary layer. In our simulations, mineral dust heated the lower atmosphere with a maximum heating rate of 9 K/day. The dust storm reduced the downwelling shortwave radiation at the surface to a maximum daily average value of -134 Wm-2 and the daily averaged long-wave forcing at the surface increased to 43 Wm-2. The combined short-wave cooling and long-wave warming effects of dust aerosols caused significant reduction in the surface air temperature -6.7 K at 1200 UTC on 19 March 2013.

  7. High-level vancomycin resistant Enterococcus faecium related to humans and pigs found in dust from pig breeding facilities.

    PubMed

    Braga, Teresa M; Pomba, Constança; Lopes, M Fátima Silva

    2013-01-25

    Environmental dust from animal breeding facilities was never screened for the presence of enterococci, nor of vancomycin-resistant enterococci (VRE), despite the possibility of being a vehicle of transmission of strains and antibiotic resistance genes between food-producing animals and man. Bio-security measures in pig facilities include disinfection with biocides to avoid the dissemination of opportunistic pathogenic bacteria, namely enterococci and in particular VRE. We thus undertook collection of enterococci and VRE in a representative number of breeding pig facilities in Portugal (n=171) and analyzed their susceptibility to benzalkonium chloride (BC) and chlorhexidine (CHX). A prevalence of 15% of VRE was found, with 6% high-level resistance found, and MIC values for CHX and BC were similar to those commonly found among enterococcal isolates from related environments, 8 μg/ml and 4 μg/ml, respectively. Among the isolated high-level vancomycin resistant Enterococcus faecium carrying the vanA genotype, we found multilocus sequence types closely related to pig and human isolates from European countries and Brazil. These results strongly advise constant surveillance of this environment and its inclusion in future epidemiologic studies on VRE. PMID:22909989

  8. Indoor Dust Allergen Levels in the Homes of Patients with Childhood Asthma: An Experience From Southwestern Iran.

    PubMed

    Moghtaderi, Mozhgan; Farjadian, Shirin; Fereidouni, Mohammad; Nasiri, Mahboubeh; Nejat, Arsalan

    2016-04-01

    Exposure to indoor allergens plays an important role in the etiology of asthma. This study was designed to quantify indoor allergens from homes of families that had at least one case of childhood asthma at home in a southwestern city of Iran. The relationship between the indoor allergen levels and home characteristics was also investigated. Dust samples were collected from the bedrooms and the kitchens of 35 homes where children with persistent asthma were living. The levels of indoor allergens were measured by enzyme linked immunosorbent assay (ELISA). Detectable amounts of mite, mouse and cockroach allergens were found in all evaluated places. None of our patients were exposed to a threshold concentration of indoor allergen for sensitizing at home. Regarding of mite allergens, the levels of Der f1 were significantly higher than Der p1 and a direct correlation was observed between living in an apartment and Der f1 levels. Moreover, Fel d1 (cat) and Bla g1 (cockroach) allergens were found in the children's bedrooms more frequently than those in the kitchens. In this study, direct associations were obtained between Bla g1 allergen and the duration of occupancy and between Fel d1 and average home size. A total of 34.2% of the patients showed positive skin reactions to at least one of the tested allergens as 17.1% of them showed reactivity to D. pteronyssinus. Proper controlling of cockroaches and mice by public health officials would be a practical approach to avoid inducing asthma or worsening the symptoms. PMID:27090366

  9. An investigation of environmental levels of cadmium and lead in airborne matter and surface soils within the locality of a municipal waste incinerator.

    PubMed

    Collett, R S; Oduyemi, K; Lill, D E

    1998-01-19

    The results of an investigation into the environmental impact of heavy metals in the airborne emissions from the Baldovie municipal waste incinerator, Scotland, are presented. A sampling network of 1-km grid squares covering a 7 x 9 km area was established over the incinerator plant and its surroundings. Surface soil core samples were collected from within each 1 km2 and analysed for cadmium and lead content. The spatial distribution of lead levels in soils showed a marked variation downwind from the Baldovie incinerator in comparison with the background level for the area but remained well within the typical range of lead in rural, unpolluted, British soils. A comparison of the observed levels of lead in local soils, with the predicted downwind long-term ground level lead distribution in air indicates that atmospheric emissions of lead originating from the Baldovie incinerator directly determine concentrations of lead in soils within a radius of 5 km of the incinerator. An empirical relationship between the levels of lead in soils and the long-term levels in air was established. In the case of cadmium, the spatial distribution of the heavy metal showed neither a marked nor extensive contamination of the sampled area around the incinerator and remained within the typical range of cadmium levels in rural, unpolluted, British soils. The work concludes that atmospheric emissions of lead from the Baldovie incinerator significantly determines the local distribution of lead in soils within the immediate vicinity of the incinerator. PMID:9514037

  10. Airborne endotoxin associated with particles of different sizes and affected by water content in handled straw.

    PubMed

    Madsen, A M; Nielsen, S H

    2010-07-01

    High exposures to endotoxin are observed in environments where organic materials are handled and lower exposures are found in e.g. indoor air. Inhaled endotoxin contributes significantly to the induction of airway inflammation and dysfunction. The size of an inhaled particle influences the deposition in the airways and the following health symptoms. The objective is to characterise the distribution of endotoxin on airborne particles of different sizes in straw storage halls with high exposure and in other environments with lower exposure levels to endotoxin. Furthermore we have studied the influence of water content of handled straw on the size distribution of endotoxin containing particles. Total, inhalable, thoracic and respirable endotoxin and particles have each been quantified in aerosols from boiler rooms and straw storage halls at 24 power plants, including 21 biofuel plants. Inhalable, thoracic and respirable endotoxin have been quantified in aerosols from offices and outdoor air. The endotoxin concentration was higher in airborne thoracic dust than in airborne 'total dust'. The median respirable fraction in the straw storage halls, boiler rooms at biofuel plants, boiler rooms at conventional plants, offices and outdoors was respectively 42%, 9%, 19%, 24% and 34%. Thoracic endotoxin per number of thoracic particles was higher than respirable endotoxin per number of respirable particles at the biofuel plants. In straw storage halls the fraction of endotoxin of respirable size was highest on the days with lowest water content in the received straw. Furthermore the exposures to all endotoxin fractions were highest on days with the lowest water content in the received straw. In conclusion the highest exposures and concentrations of endotoxin occur or tend to occur from thoracic dust. A high variation in endotoxin concentrations and in fractions of respirable or thoracic size is found in the different working areas. This is important in the risk assessment and

  11. The role of deep convection and nocturnal low-level jets for dust emission in summertime West Africa: Estimates from convection-permitting simulations

    NASA Astrophysics Data System (ADS)

    Heinold, B.; Knippertz, P.; Marsham, J. H.; Fiedler, S.; Dixon, N. S.; Schepanski, K.; Laurent, B.; Tegen, I.

    2013-05-01

    Convective cold pools and the breakdown of nocturnal low-level jets (NLLJs) are key meteorological drivers of dust emission over summertime West Africa, the world's largest dust source. This study is the first to quantify their relative contributions and physical interrelations using objective detection algorithms and an off-line dust emission model applied to convection-permitting simulations from the Met Office Unified Model. The study period covers 25 July to 02 September 2006. All estimates may therefore vary on an interannual basis. The main conclusions are as follows: (a) approximately 40% of the dust emissions are from NLLJs, 40% from cold pools, and 20% from unidentified processes (dry convection, land-sea and mountain circulations); (b) more than half of the cold-pool emissions are linked to a newly identified mechanism where aged cold pools form a jet above the nocturnal stable layer; (c) 50% of the dust emissions occur from 1500 to 0200 LT with a minimum around sunrise and after midday, and 60% of the morning-to-noon emissions occur under clear skies, but only 10% of the afternoon-to-nighttime emissions, suggesting large biases in satellite retrievals; (d) considering precipitation and soil moisture effects, cold-pool emissions are reduced by 15%; and (e) models with parameterized convection show substantially less cold-pool emissions but have larger NLLJ contributions. The results are much more sensitive to whether convection is parameterized or explicit than to the choice of the land-surface characterization, which generally is a large source of uncertainty. This study demonstrates the need of realistically representing moist convection and stable nighttime conditions for dust modeling.

  12. Manganese concentrations in soil and settled dust in an area with historic ferroalloy production

    PubMed Central

    Pavilonis, Brian T.; Lioy, Paul J.; Guazzetti, Stefano; Bostick, Benjamin C.; Donna, Filippo; Peli, Marco; Zimmerman, Neil J.; Bertrand, Patrick; Lucas, Erika; Smith, Donald R.; Georgopoulos, Panos G.; Mi, Zhongyuan; Royce, Steven G.; Lucchini, Roberto G.

    2015-01-01

    Ferroalloy production can release a number of metals into the environment, of which manganese (Mn) is of major concern. Other elements include lead, iron, zinc, copper, chromium, and cadmium. Manganese exposure derived from settled dust and suspended aerosols can cause a variety of adverse neurological effects to chronically exposed individuals. To better estimate the current levels of exposure, this study quantified metal levels in dust collected inside homes (n=85), outside homes (n=81), in attics (n=6), and in surface soil (n=252) in an area with historic ferroalloy production. Metals contained in indoor and outdoor dust samples were quantified using inductively coupled plasma optical emission spectroscopy while attic and soil measurements were made with a XRF instrument. Mean Mn concentrations in soil (4600 μg/g) and indoor dust (870 μg/g) collected within 0.5 km of a plant exceeded levels previously found in suburban and urban areas, but did decrease outside 1.0 km to the upper end of background concentrations. Mn concentrations in attic dust were approximately 120 times larger than other indoor dust levels, consistent with historical emissions that yielded high airborne concentrations in the region. Considering the potential health effects that are associated with chronic manganese inhalation and ingestion exposure, remediation of soil near the plants and frequent, on-going hygiene indoors may decrease residential exposure and the likelihood of adverse health effects. PMID:25335867

  13. Manganese concentrations in soil and settled dust in an area with historic ferroalloy production.

    PubMed

    Pavilonis, Brian T; Lioy, Paul J; Guazzetti, Stefano; Bostick, Benjamin C; Donna, Filippo; Peli, Marco; Zimmerman, Neil J; Bertrand, Patrick; Lucas, Erika; Smith, Donald R; Georgopoulos, Panos G; Mi, Zhongyuan; Royce, Steven G; Lucchini, Roberto G

    2015-01-01

    Ferroalloy production can release a number of metals into the environment, of which manganese (Mn) is of major concern. Other elements include lead, iron, zinc, copper, chromium, and cadmium. Mn exposure derived from settled dust and suspended aerosols can cause a variety of adverse neurological effects to chronically exposed individuals. To better estimate the current levels of exposure, this study quantified the metal levels in dust collected inside homes (n=85), outside homes (n=81), in attics (n=6), and in surface soil (n=252) in an area with historic ferroalloy production. Metals contained in indoor and outdoor dust samples were quantified using inductively coupled plasma optical emission spectroscopy, whereas attic and soil measurements were made with a X-ray fluorescence instrument. Mean Mn concentrations in soil (4600 μg/g) and indoor dust (870 μg/g) collected within 0.5 km of a plant exceeded levels previously found in suburban and urban areas, but did decrease outside 1.0 km to the upper end of background concentrations. Mn concentrations in attic dust were ~120 times larger than other indoor dust levels, consistent with historical emissions that yielded high airborne concentrations in the region. Considering the potential health effects that are associated with chronic Mn inhalation and ingestion exposure, remediation of soil near the plants and frequent, on-going hygiene indoors may decrease residential exposure and the likelihood of adverse health effects. PMID:25335867

  14. Real-time PCR quantification of infectious laryngotracheitis virus in chicken tissues, faeces, isolator-dust and bedding material over 28 days following infection reveals high levels in faeces and dust.

    PubMed

    Roy, Parimal; Fakhrul Islam, A F M; Burgess, Susan K; Hunt, Peter W; McNally, Jody; Walkden-Brown, Stephen W

    2015-11-01

    Infectious laryngotracheitis (ILT) is an important disease of chickens caused by ILT virus (ILTV). We used the Australian SA2 and A20 vaccine strains of ILTV to determine tissue distribution and excretion characteristics of ILTV in specific-pathogen-free chickens and to determine whether ILTV is readily detectable in environmental samples such as faeces, bedding material and dust using real-time quantitative PCR. Three groups of 10 freshly hatched chicks were placed in isolators and infected orally with high doses of the two strains of vaccine virus or left unchallenged as controls. Over a 28-day post-infection (p.i.) period, faecal and serum samples were collected at frequent intervals from six individually identified chickens in each group. Dust and litter samples from the isolators were collected less frequently. Tissue samples were collected from three to four sacrificed or dead/euthanized birds at 6, 14 and 28 days p.i. Infection resulted in clinical ILT, a pronounced antibody response and sustained qPCR detection of the viral genome in the trachea, Harderian gland, lung and kidney up to 28 days p.i. A high level of the viral genome was also detected in faeces between 2 and 7 days p.i., declining by about approximately four orders of magnitude to low, but detectable, levels at 21 and 28 days p.i. The finding of high-level shedding of ILTV in faeces warrants further investigation into the epidemiological role of this, and the sustained high levels of ILTV observed in dust suggest that it may be a useful sample material for monitoring ILTV status in flocks. PMID:26294959

  15. The Continuous Monitoring of Desert Dust using an Infrared-based Dust Detection and Retrieval Method

    NASA Technical Reports Server (NTRS)

    Duda, David P.; Minnis, Patrick; Trepte, Qing; Sun-Mack, Sunny

    2006-01-01

    Airborne dust and sand are significant aerosol sources that can impact the atmospheric and surface radiation budgets. Because airborne dust affects visibility and air quality, it is desirable to monitor the location and concentrations of this aerosol for transportation and public health. Although aerosol retrievals have been derived for many years using visible and near-infrared reflectance measurements from satellites, the detection and quantification of dust from these channels is problematic over bright surfaces, or when dust concentrations are large. In addition, aerosol retrievals from polar orbiting satellites lack the ability to monitor the progression and sources of dust storms. As a complement to current aerosol dust retrieval algorithms, multi-spectral thermal infrared (8-12 micron) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Meteosat-8 Spinning Enhanced Visible and Infrared Imager (SEVIRI) are used in the development of a prototype dust detection method and dust property retrieval that can monitor the progress of Saharan dust fields continuously, both night and day. The dust detection method is incorporated into the processing of CERES (Clouds and the Earth s Radiant Energy System) aerosol retrievals to produce dust property retrievals. Both MODIS (from Terra and Aqua) and SEVERI data are used to develop the method.

  16. Mechanical intervention for reducing dust concentration in traditional rice mills

    PubMed Central

    PRANAV, Prabhanjan K.; BISWAS, Mrinmoy

    2016-01-01

    A huge number of workers are employed in traditional rice mills where they are potentially exposed to dust. In this study a dust collection system was developed to capture the airborne dust in the rice mill. The feeding and sieving section of the mill was identified as major dust creating zone. The dust was captured by creating suitable air stream at feeding and sieving sections of the mill and collected in cyclone dust collector. The air stream was created by blower which was selected on the basis to get minimum air speed of 0.5 m/s in the working zones of workers. It was observed that the developed system is successfully collects the significant amount of dust and able to reduce the dust concentration up to 58%. Further, the respirable dust concentration reduced to below 5 mg/m3 throughout the mill which is within the recommended limit of dust exposure. PMID:26829976

  17. Dust Detector

    NASA Technical Reports Server (NTRS)

    Kelley, M. C.

    2001-01-01

    We discuss a recent sounding rocket experiment which found charged dust in the Earth's tropical mesosphere. The dust detector was designed to measure small (5000 - 10000 amu.) charged dust particles, most likely of meteoric origin. A 5 km thick layer of positively charged dust was found at an altitude of 90 km, in the vicinity of an observed sporadic sodium layer and sporadic E layer. The observed dust was positively charged in the bulk of the dust layer, but was negatively charged near the bottom.

  18. Impact of the Saharan dust outbreaks on the ambient levels of total suspended particles (TSP) in the marine boundary layer (MBL) of the Subtropical Eastern North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Alonso-Pérez, S.; Cuevas, E.; Querol, X.; Viana, M.; Guerra, J. C.

    Six years (1998-2003) of measurements of ambient air concentrations of total suspended particulate (TSP) measured at a rural background monitoring station in Tenerife (Canary Islands), the El Río station (ER, 28°08'35″N, 16°39'20″W, 500 m a.s.l.) were studied. African dust outbreaks were objectively identified using a new quantitative tool, called the African Index. This index indicates the percentage of time that an air mass remained over an African region at one of three possible height intervals of the lower troposphere. After identifying these episodes, a study of the background TSP levels at the ER station and of direct and indirect (those which cause vertical deposition of dust) African air mass intrusion impacts was performed. Taking into account both direct and indirect episodes, a total of 322 days of African dust intrusion were objectively identified (a mean of 54 episodes per year) in the period 1998-2003, some of them caused by "transition episodes" or "return African air masses". A subjective method confirmed that 256 of these days were caused by direct impacts of African dust on the ER station. A mean TSP value of 21.6 μg m -3 was found at the station during this period. All the episodes occurred when the TSP concentration was >28.5 μg m -3. The TSP background (˜14 μg m -3) can be assumed to be representative of the MBL of the Eastern North Atlantic subtropical region. The highest number of dust gravitational settlement (or indirect) episodes occurs in summer, but the highest contribution of these episodes to the TSP levels is in March with a monthly mean TSP contribution of up to 30.5 μg m -3.

  19. 30 CFR 33.4 - Types of dust collectors for which certificates of approval may be granted.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONNECTION WITH ROCK DRILLING IN COAL MINES General Provisions § 33.4 Types of dust collectors for which... specifically to prevent dissemination of airborne dust generated by drilling into coal-mine rock strata...

  20. 30 CFR 33.4 - Types of dust collectors for which certificates of approval may be granted.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CONNECTION WITH ROCK DRILLING IN COAL MINES General Provisions § 33.4 Types of dust collectors for which... specifically to prevent dissemination of airborne dust generated by drilling into coal-mine rock strata...

  1. Levels, distributions and correlations of polybrominated diphenyl ethers in air and dust of household and workplace in Shanghai, China: implication for daily human exposure.

    PubMed

    Xu, Feng; Tang, Weibiao; Zhang, Wei; Liu, Lili; Lin, Kuangfei

    2016-02-01

    Polybrominated diphenyl ethers (PBDEs) were measured in air (TSP and PM2.5) and dust samples collected from 16 households and the corresponding workplaces of eight volunteer citizens in Shanghai, China. The PBDEs concentrations in the workplace air (mean: 281 ± 126 pg m(-3)) were over two times higher than those in the household (121 ± 44.0 pg m(-3)), while the mean levels of PBDEs in dust were 995 ± 547 and 544 ± 188 ng g(-1) for workplace and household, respectively. BDE209 was the most abundant congener in all samples. PBDEs appeared to be composed of mostly small particles. The C particle/C dust ratios of less brominated PBDEs in PM2.5 were higher than those in TSP, while the values were approximately constant for the more brominated PBDEs. A correlation analysis by network indicated different sources and behavior of the PBDE congeners. The results of a cluster analysis were displayed on a heat map that specified the source and abundance of each PBDE congener. The daily PBDE exposure via dust ingestion was the predominant part of the total intake and was more than 10 times higher than the intake via inhalation. PMID:26490892

  2. The role of deep convection and nocturnal low-level jets for dust emission in summertime West Africa: Estimates from convection-permitting simulations

    PubMed Central

    Heinold, B; Knippertz, P; Marsham, JH; Fiedler, S; Dixon, NS; Schepanski, K; Laurent, B; Tegen, I

    2013-01-01

    [1] Convective cold pools and the breakdown of nocturnal low-level jets (NLLJs) are key meteorological drivers of dust emission over summertime West Africa, the world’s largest dust source. This study is the first to quantify their relative contributions and physical interrelations using objective detection algorithms and an off-line dust emission model applied to convection-permitting simulations from the Met Office Unified Model. The study period covers 25 July to 02 September 2006. All estimates may therefore vary on an interannual basis. The main conclusions are as follows: (a) approximately 40% of the dust emissions are from NLLJs, 40% from cold pools, and 20% from unidentified processes (dry convection, land-sea and mountain circulations); (b) more than half of the cold-pool emissions are linked to a newly identified mechanism where aged cold pools form a jet above the nocturnal stable layer; (c) 50% of the dust emissions occur from 1500 to 0200 LT with a minimum around sunrise and after midday, and 60% of the morning-to-noon emissions occur under clear skies, but only 10% of the afternoon-to-nighttime emissions, suggesting large biases in satellite retrievals; (d) considering precipitation and soil moisture effects, cold-pool emissions are reduced by 15%; and (e) models with parameterized convection show substantially less cold-pool emissions but have larger NLLJ contributions. The results are much more sensitive to whether convection is parameterized or explicit than to the choice of the land-surface characterization, which generally is a large source of uncertainty. This study demonstrates the need of realistically representing moist convection and stable nighttime conditions for dust modeling. Citation: Heinold, B., P. Knippertz, J. H. Marsham, S. Fiedler, N. S. Dixon, K. Schepanski, B. Laurent, and I. Tegen (2013), The role of deep convection and nocturnal low-level jets for dust emission in summertime West Africa: Estimates from convection

  3. Fingerprints in the Dust

    NASA Technical Reports Server (NTRS)

    2001-01-01

    These MISR nadir-camera images of eastern China compare a somewhat hazy summer view from July 9, 2000 (left) with a spectacularly dusty spring view from April 7, 2001 (middle). The left-hand and middle images are from Terra orbits 2967 and 6928, respectively, and extend from central Manchuria near the top to portions of North and South Korea at the bottom. They are approximately 380 kilometers in width.

    Asia's desert areas are prone to soil erosion, as underground water tables are lowered by prolonged drought and by industrial and agricultural water use. Heavy winds blowing eastward across the arid and sparsely vegetated surfaces of Mongolia and western China pick up large quantities of yellow dust. Airborne dust clouds from the April 2001 storm blew across the Pacific Ocean and were carried as far as North America. The minerals transported in this manner are believed to provide nutrients for both oceanic and land ecosystems.

    According to the Xinhua News Agency in China, nearly one million tons of Gobi Desert dust blow into Beijing each year. During a similar dust outbreak last year, the Associated Press reported that the visibility in Beijing had been reduced the point where buildings were barely visible across city streets, and airline schedules were significantly disrupted. The dust has also been implicated in adverse health effects such as respiratory discomfort and eye irritation.

    The image on the right is a higher resolution MISR nadir-camera view of a portion of the April 7, 2001 dust cloud. It covers an area roughly 250 kilometers wide by 470 kilometers high. When viewed at full magnification, a number of atmospheric wave features, like the ridges and valleys of a fingerprint, are apparent. These are probably induced by surface topography, which can disturb the wind flow. A few small cumulus clouds are also visible, and are casting shadows on the thick lower dust layer.

    Analyses of images such as these constitute one phase of MISR

  4. 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.

  5. House dust in seven Danish offices

    NASA Astrophysics Data System (ADS)

    Mølhave, L.; Schneider, T.; Kjærgaard, S. K.; Larsen, L.; Norn, S.; Jørgensen, O.

    Floor dust from Danish offices was collected and analyzed. The dust was to be used in an exposure experiment. The dust was analyzed to show the composition of the dust which can be a source of airborne dust indoors. About 11 kg of dust from vacuum cleaner bags from seven Danish office buildings with about 1047 occupants (12 751 m 2) was processed according to a standardized procedure yielding 5.5 kg of processed bulk dust. The bulk dust contained 130.000-160.000 CFU g -1 microorganisms and 71.000-90.000 CFU g -1 microfungi. The content of culturable microfungi was 65-123 CFU 30 g -1 dust. The content of endotoxins ranged from 5.06-7.24 EU g -1 (1.45 ng g -1 to 1.01 ng g -1). Allergens (ng g -1) were from 147-159 (Mite), 395-746 (dog) and 103-330 (cat). The macro molecular organic compounds (the MOD-content) varied from 7.8-9.8 mg g -1. The threshold of release of histamine from basophil leukocytes provoked by the bulk dust was between 0.3 and 1.0 mg ml -1. The water content was 2% (WGT) and the organic fraction 33%. 6.5-5.9% (dry) was water soluble. The fiber content was less than 0.2-1.5% (WGT) and the desorbable VOCs was 176-319 μg g -1. Most of the VOC were aldehydes. However, softeners for plastic (DBP and DEHP) were present. The chemical composition includes human and animal skin fragments, paper fibers, glass wool, wood and textilefibers and inorganic and metal particles. The sizes ranged from 0.001-1 mm and the average specific density was 1.0 g m -3. The bulk dust was resuspended and injected into an exposure chamber. The airborne dust was sampled and analyzed to illustrate the exposures that can result from sedimented dirt and dust. The airborne dust resulting from the bulk dust reached concentrations ranging from 0.26-0.75 mg m -3 in average contained 300-170 CFU m -3. The organic fraction was from 55-70% and the water content about 2.5% (WGT). The content of the dust was compared to the similar results reported in the literature and its toxic potency is

  6. Dust suppression in swine feed using soybean oil.

    PubMed

    Mankell, K O; Janni, K A; Walker, R D; Wilson, M E; Pettigrew, J E; Jacobson, L D; Wilcke, W F

    1995-04-01

    Dust generation from swine feed (corn-soybean meal diet) treated with soybean oil was investigated using a cement mixer in a plywood box. Airborne total dust concentrations in the box were measured gravimetrically using a vacuum pump and filters while 12-kg feed samples were constantly mixed. The treatment factors were soybean oil concentration (0, 1, and 3%), corn bulk density (normal, 730 kg/m3 and low, 600 kg/m3), time of oil addition (before vs after grinding the corn), and storage time (0, 7, and 14 d). The feed was a mixture of soybean meal, base mix, and adjusted amounts of ground corn and soybean oil. Adding soybean oil after grinding at 1 and 3% levels to feed made with normal-bulk density corn suppressed total dust generation (3.39 and .99 mg/m3, respectively) (P < .001) compared with the no oil treatment (29.1 mg/m3). The 3% soybean oil treatment suppressed dust generation (.99 mg/m3) more than the 1% soybean oil treatment (3.39 mg/m3) (P < .001). Adding soybean oil after grinding the corn suppressed dust generation more than adding the oil to the corn before grinding for every oil level (P < .001). More dust was generated by feed made from low-bulk density corn than by feed made with normal-bulk density corn at every oil level (P < .001). There was no evidence of any storage time or treatment x storage time interactions. PMID:7628976

  7. Cosmic dust

    NASA Technical Reports Server (NTRS)

    Brownlee, Donald E.; Sandford, Scott A.

    1992-01-01

    Dust is a ubiquitous component of our galaxy and the solar system. The collection and analysis of extraterrestrial dust particles is important to exobiology because it provides information about the sources of biogenically significant elements and compounds that accumulated in distant regions of the solar nebula and that were later accreted on the planets. The topics discussed include the following: general properties of interplanetary dust; the carbonaceous component of interplanetary dust particles; and the presence of an interstellar component.

  8. Tikhonravov Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches are located within a small crater inside Tikhonravov Crater.

    Image information: VIS instrument. Latitude 12.6, Longitude 37.1 East (322.9 West). 36 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  9. Lycus Sulci Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches occur on the slopes of Lycus Sulci near Olympus Mons.

    Image information: VIS instrument. Latitude 28.1, Longitude 220.4 East (139.6 West). 18 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  10. Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches are located in a small canyon within a crater rim northeast of Naktong Vallis.

    Image information: VIS instrument. Latitude 7.1, Longitude 34.7 East (325.3 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  11. Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    This region of dust avalanches is located in and around a crater to the west of yesterday's image.

    Image information: VIS instrument. Latitude 14.7, Longitude 32.7 East (327.3 West). 18 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  12. Far-infrared to millimeter astrophysical dust emission. II. Comparison of the two-level systems (TLS) model with astronomical data

    NASA Astrophysics Data System (ADS)

    Paradis, D.; Bernard, J.-P.; Mény, C.; Gromov, V.

    2011-10-01

    Aims: In a previous paper we proposed a new model for the emission by amorphous astronomical dust grains, based on solid-state physics. The model uses a description of the disordered charge distribution (DCD) combined with the presence of two-level systems (TLS) defects in the amorphous solid composing the grains. The goal of this paper is to compare this new model to astronomical observations of different Galactic environments in the far-infrared/submillimeter, in order to derive a set of canonical model parameters to be used as a Galactic reference to be compared to in future Galactic and extragalactic studies. Methods: We compare the TLS model with existing astronomical data. We consider the average emission spectrum at high latitudes in our Galaxy as measured with FIRAS and WMAP, as well as the emission from Galactic compact sources observed with the Archeops balloon experiment, for which an inverse relationship between the dust temperature and the emissivity spectral index has been shown. Results: We show that, unlike models previously proposed that often invoke two dust components at different temperatures, the TLS model successfully reproduces both the shape of the Galactic spectral energy distribution and its evolution with temperature as observed in the Archeops data. The best TLS model parameters indicate a charge coherence length of ≃13 nm and other model parameters in broad agreement with expectations from laboratory studies of dust analogs. We conclude that the millimeter excess emission, which is often attributed to the presence of very cold dust in the diffuse ISM, is very likely caused solely by TLS emission in disordered amorphous dust grains. We discuss the implications of the new model, in terms of mass determinations from millimeter continuum observations and the expected variations in the emissivity spectral index with wavelength and dust temperature. The implications for analyzing the Herschel and Planck satellite data are discussed. Table 5

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

    PubMed Central

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

    2015-01-01

    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. PMID:26834390

  14. The effects of Eucheuma cottonii on alveolar macrophages and malondialdehyde levels in bronchoalveolar lavage fluid in chronically particulate matter 10 coal dust-exposed rats

    PubMed Central

    Saputri, Romadhiyana Kisno; Setiawan, Bambang; Nugrahenny, Dian; Kania, Nia; Wahyuni, Endang Sri; Widodo, M Aris

    2014-01-01

    Objective(s): To investigate the effect of Eucheuma cottonii on alveolar macrophages (AM) and malondialdehyde (MDA) levels in bronchoalveolar lavage fluids (BALF) in particulate matter 10 (PM10) coal dust-exposed rats. Materials and Methods: Ten groups, including a non exposed group and groups exposed to coal dust at doses of 6.25 (CD6.25), 12.5 (CD12.5), or 25 mg/m3 (CD25) an hour daily for 6 months with or without supplementation of ethanolic extract of E. cottonii at doses of 150 (EC150) or 300 mg/kg BW (EC300). The number of macrophages was determined using a light microscope. MDA levels were measured by TBARS assay. Results: EC150 insignificantly (P > 0.05) reduces the AM in CD groups compared to non treatment groups. EC150 and EC300 significantly (P < 0.05) decreased MDA levels in CD12.5 and CD25 groups relative to non treatment groups. Conclusion: E. cottonii attenuated oxidative stress in chronic exposure of PM10 coal dust. PMID:25429347

  15. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    article title:  Massive Dust Storm over Australia     View ... at JPL September 22, 2009 - Massive dust storm over Australia. project:  MISR category:  ... Sep 22, 2009 Images:  Dust Storm location:  Australia and New Zealand ...

  16. Sahara Dust

    Atmospheric Science Data Center

    2013-04-15

    article title:  Casting Light and Shadows on a Saharan Dust Storm     ... (nadir) camera. High-altitude cirrus clouds cast shadows on the underlying ocean and dust layer, which are visible in shades of ... was unable to retrieve elevation data. However, the edges of shadows cast by the cirrus clouds onto the dust (indicated by blue and cyan ...

  17. Desert Dust Exposure Is Associated with Increased Risk of Asthma Hospitalization in Children

    PubMed Central

    Kanatani, Kumiko T.; Ito, Isao; Al-Delaimy, Wael K.; Adachi, Yuichi; Mathews, William C.; Ramsdell, Joe W.

    2010-01-01

    Rationale: Desert dust particles, including quartz, which causes inflammatory responses in the airway in animal studies, are transported to widespread regions around the globe. Epidemiologically, areas impacted by desert dust storms, such as communities in the Middle East and the Caribbean, seem to have higher incidences of asthma than might be expected. Objectives: We investigated the magnitude of association between airborne mineral dust concentration and hospitalization of children for asthma exacerbation by using Light Detection And Ranging (LIDAR) with a polarization analyzer for an exposure measurement, which can distinguish mineral dust particles from other particles. Methods: A case-crossover design was used. The exposure measurement was LIDAR's nonspherical extinction coefficient. The outcome measurement was hospitalization of children aged 1 to 15 years for asthma exacerbation in eight principal hospitals in Toyama, a local area in Japan bordering the Japan Sea, during February to April, 2005 to 2009. Measurements and Main Results: During the study period, there were 620 admissions for asthma exacerbation, and 6 days with a heavy dust event (daily mineral dust concentration > 0.1 mg/m3). Conditional logistic regression showed a statistically significant association between asthma hospitalization and a heavy dust event. The crude odds ratio (OR) of the heavy dust event for hospitalization on the day was 1.88 (95% confidence interval [CI], 1.04–3.41; P = 0.037), and the OR of heavy dust event during the previous week was 1.83 (95% CI, 1.31–2.56; P = 0.00043). The OR adjusted by other air pollutant levels, pollen, and meteorological factors was 1.71 (95% CI, 1.18–2.48; P = 0.0050). Conclusions: Heavy dust events are associated with an increased risk of hospitalizations for asthma. PMID:20656941

  18. Characterization of dust emission from alluvial sources using aircraft observations and high-resolution modeling

    NASA Astrophysics Data System (ADS)

    Schepanski, Kerstin; Flamant, Cyrille; Chaboureau, Jean-Pierre; Kocha, Cecile; Banks, Jamie; Brindley, Helen; Lavaysse, Christophe; Marnas, Fabien; Pelon, Jacques; Tulet, Pierre

    2013-04-01

    We investigate mineral dust emission from alluvial sediments within the upland region in northern Mauritania in the vicinity of a decaying nocturnal low-level jet (LLJ). For the first time, the impact of valleys that are embedded in a rather homogeneous surrounding is investigated with regard to their role as dust source. Measures for local atmospheric dust burden were retrieved from airborne observations, satellite observations, and model simulations and analyzed in order to provide complementary information at different horizontal scales. Observations by the LNG backscatter lidar system flying aboard the SAFIRE Falcon 20 aircraft were taken along five parallel flight legs perpendicular to the orientation of the main valley system dominating the topography of the study area. Results from a comparison of lidar-derived extinction coefficients with topography and aerial photographs confirm the relevance of (1) alluvial sediments at the valley bottoms as a dust source, and (2) the break-down of the nocturnal LLJ as a trigger for dust emission in this region. An evaluation of the AROME regional model, forecasting dust at high resolution (5 km grid), points towards an underrepresentation of alluvial dust sources in this region. This is also evident from simulations by the MesoNH research model. Although MesoNH simulations show higher dust loadings than AROME which are more comparable to the observations, both models understimate the dust concentrations within the boundary layer compared to lidar observations. A sensitivity study on the impact of horizontal grid spacing (5 km versus 1 km) highlights the importance of spatial resolution on simulated dust loadings.

  19. Pulmonary and Systemic Immune Response to Chronic Lunar Dust Inhalation

    NASA Technical Reports Server (NTRS)

    Crucian, Brian; Quiriarte, Heather; Nelman, Mayra; Lam, Chiu-wing; James, John T.; Sams, Clarence

    2014-01-01

    Background: Due to millennia of meteorite impact with virtually no erosive effects, the surface of the Moon is covered by a layer of ultra-fine, reactive Lunar dust. Very little is known regarding the toxicity of Lunar dust on human physiology. Given the size and electrostatic characteristics of Lunar dust, countermeasures to ensure non-exposure of astronauts will be difficult. To ensure astronaut safety during any future prolonged Lunar missions, it is necessary to establish the effect of chronic pulmonary Lunar dust exposure on all physiological systems. Methods: This study assessed the toxicity of airborne lunar dust exposure in rats on pulmonary and system immune system parameters. Rats were exposed to 0, 20.8, or 60.8 mg/m3 of lunar dust (6h/d; 5d/wk) for up to 13 weeks. Sacrifices occurred after exposure durations of 1day, 7 days, 4 weeks and 13 weeks post-exposure, when both blood and lung lavage fluid were collected for analysis. Lavage and blood assays included leukocyte distribution by flow cytometry, electron/fluorescent microscopy, and cytokine concentration. Cytokine production profiles following mitogenic stimulation were performed on whole blood only. Results: Untreated lavage fluid was comprised primarily of pulmonary macrophages. Lunar dust inhalation resulted in an influx of neutrophils and lymphocytes. Although the percentage of lymphocytes increased, the T cell CD4:CD8 ratio was unchanged. Cytokine analysis of the lavage fluid showed increased levels of IL-1b and TNFa. These alterations generally persisted through the 13 week sampling. Blood analysis showed few systemic effects from the lunar dust inhalation. By week 4, the peripheral granulocyte percentage was elevated in the treated rats. Plasma cytokine levels were unchanged in all treated rats compared to controls. Peripheral blood analysis showed an increased granulocyte percentage and altered cytokine production profiles consisting of increased in IL-1b and IL-6, and decreased IL-2

  20. Sahelian dust lifting in the inter-tropical discontinuity region: Lidar observations and mesoscale modelling

    NASA Astrophysics Data System (ADS)

    Bou Karam, D.; Flamant, C.; Tulet, P.; Chaboureau, J.; Dabas, A.; Chong, M.; Reitebuch, O.

    2007-12-01

    Airbone lidar observations acquired with the LEANDRE 2 system during 3 flights of the SAFIRE Falcon 20 in the framework of the AMMA Special Observing Period (SOP) 2a1 (July 2006) over western Niger, revealed the existence of desert dust uptakes in the region of the inter-tropical discontinuity (ITD) in the morning hours. Complementary observations provided by dropsondes released from the same platform as well as airborne wind measurements made from another platform (the DLR Falcon 20, flying in coordination with the SAFIRE Falcon 20) evidenced that the lifting was associated with the leading edge of the monsoon low level jet, and to be transported southward by the harmattan, above the monsoon layer. A 10-day numerical simulation, using the mesoscale model Meso-NH (including the dust emission box Dust Entrainment And Deposition model), was conducted to assess the representativity of the observed phenomenon as well as the mechanisms associated with the Sahelian dust emissions. The Meso-NH simulation (initialized by and nudged with ECMWF analyses) was carried out on a 2000 km x 2000 km domain (20-km horizontal resolution) centered at 20°N and 7°E, that included the Falcons flight track, as well as numerous AMMA-related ground-based measurement sites (Tamanrasset, Agadez, Niamey/Banizoumbou, etc..) for validation purposes. In the simulation, large dust uptakes associated with the leading edge of the monsoon flow, with a dust concentration reaching 2000μg/m3, and to be transported southward by the harmattan, above the monsoon layer, were well reproduced. On the other hand, the simulation suggested the existence of dust emissions associated with the harmattan flow which were not observed by airborne lidar measurements. The reason for the discrepancy between the model results and the lidar observations is investigated.

  1. Integration of WorldView-2 and airborne LiDAR data for tree species level carbon stock mapping in Kayar Khola watershed, Nepal

    NASA Astrophysics Data System (ADS)

    Karna, Yogendra K.; Hussin, Yousif Ali; Gilani, Hammad; Bronsveld, M. C.; Murthy, M. S. R.; Qamer, Faisal Mueen; Karky, Bhaskar Singh; Bhattarai, Thakur; Aigong, Xu; Baniya, Chitra Bahadur

    2015-06-01

    Integration of WorldView-2 satellite image with small footprint airborne LiDAR data for estimation of tree carbon at species level has been investigated in tropical forests of Nepal. This research aims to quantify and map carbon stock for dominant tree species in Chitwan district of central Nepal. Object based image analysis and supervised nearest neighbor classification methods were deployed for tree canopy retrieval and species level classification respectively. Initially, six dominant tree species (Shorea robusta, Schima wallichii, Lagerstroemia parviflora, Terminalia tomentosa, Mallotus philippinensis and Semecarpus anacardium) were able to be identified and mapped through image classification. The result showed a 76% accuracy of segmentation and 1970.99 as best average separability. Tree canopy height model (CHM) was extracted based on LiDAR's first and last return from an entire study area. On average, a significant correlation coefficient (r) between canopy projection area (CPA) and carbon; height and carbon; and CPA and height were obtained as 0.73, 0.76 and 0.63, respectively for correctly detected trees. Carbon stock model validation results showed regression models being able to explain up to 94%, 78%, 76%, 84% and 78% of variations in carbon estimation for the following tree species: S. robusta, L. parviflora, T. tomentosa, S. wallichii and others (combination of rest tree species).

  2. Estimating individual-level exposure to airborne polycyclic aromatic hydrocarbons throughout the gestational period based on personal, indoor, and outdoor monitoring

    SciTech Connect

    Choi, H.; Perera, F.; Pac, A.; Wang, L.; Flak, E.; Mroz, E.; Jacek, R.; Chai-Onn, T.; Jedrychowski, W.; Masters, E.; Camann, D.; Spengler, J.

    2008-11-15

    Current understanding on health effects of long-term polycyclic aromatic hydrocarbon (PAH) exposure is limited by lack of data on time-varying nature of the pollutants at an individual level. In a cohort of pregnant women in Krakow, Poland, we examined the contribution of temporal, spatial, and behavioral factors to prenatal exposure to airborne PAHs within each trimester and developed a predictive model of PAH exposure over the entire gestational period. The observed personal, indoor, and outdoor B(a)P levels we observed in Krakow far exceed the recommended Swedish guideline value for B(a)P of 0.1 ng/m{sup 3}. Based on simultaneously monitored levels, the outdoor PAH level alone accounts for 93% of total variability in personal exposure during the heating season. Living near the Krakow bus depot, a crossroad, and the city, center and time spent outdoors or commuting were not associated with higher personal exposure. During the nonheating season only, a 1-hr increase in environmental tobacco smoke (ETS) exposure was associated with a 10-16% increase in personal exposure to the nine measured PAHs. A 1{degree}C decrease in ambient temperature was associated with a 3-5% increase in exposure to benz(a)anthracene, benzo(k)fluoranthene, and dibenz(a,h)anthracene, after accounting for the outdoor concentration. A random effects model demonstrated that mean personal exposure at a given gestational period depends on the season, residence location, and ETS. Considering that most women reported spending < 3 hr/day outdoors, most women in the study were exposed to outdoor-originating PAHs within the indoor setting. Cross-sectional, longitudinal monitoring supplemented with questionnaire data allowed development of a gestation-length model of individual-level exposure with high precision and validity.

  3. Dust vertical distribution in the Caribbean during the Puerto Rico Dust Experiment

    NASA Astrophysics Data System (ADS)

    Reid, Jeffrey S.; Westphal, Douglas L.; Livingston, John M.; Savoie, Dennis L.; Maring, Hal B.; Jonsson, Haflidi H.; Eleuterio, Daniel P.; Kinney, James E.; Reid, Elizabeth A.

    2002-04-01

    As part of Puerto Rico Dust Experiment (PRIDE), a Piper Navajo research aircraft, equipped with particle probes and an airborne Sun photometer, was deployed to Puerto Rico in July 2000. During the study, mid-visible optical depths in Puerto Rico due to dust reached 0.5. In the middle of the summer transport season, the vertical distributions of dust were similar to that commonly assumed in the region with dust concentrated in the Saharan Air Layer (SAL) aloft. However, during the first half of the study period, dust had the highest concentrations in the marine and convective boundary layers, with lower dust concentrations above the trade inversion despite the presence of a strong SAL. Supporting meteorology suggests that the state of the monsoon on the coast of Africa influences the nature of the vertical distribution of dust in the Caribbean.

  4. Circumstellar dust

    NASA Technical Reports Server (NTRS)

    Dwek, E.

    1986-01-01

    The presence of dust in the general interstellar medium is inferred from the extinction, polarization, and scattering of starlight; the presence of dark nebulae; interstellar depletions; the observed infrared emission around certain stars and various types of interstellar clouds. Interstellar grains are subject to various destruction mechanisms that reduce their size or even completely destroy them. A continuous source of newly formed dust must therefore be present for dust to exist in the various phases of the interstellar medium (ISM). The working group has the following goals: (1) review the evidences for the formation of dust in the various sources; (2) examine the clues to the nature and composition of the dust; (3) review the status of grain formation theories; (4) examine any evidence for the processing of the dust prior to its injection into the interstellar medium; and (5) estimate the relative contribution of the various sources to the interstellar dust population.

  5. Determination of sound types and source levels of airborne vocalizations by California sea lions, Zalophus californianus, in rehabilitation at the Marine Mammal Center in Sausalito, California

    NASA Astrophysics Data System (ADS)

    Schwalm, Afton Leigh

    California sea lions (Zalophus californianus) are a highly popular and easily recognized marine mammal in zoos, aquariums, circuses, and often seen by ocean visitors. They are highly vocal and gregarious on land. Surprisingly, little research has been performed on the vocalization types, source levels, acoustic properties, and functions of airborne sounds used by California sea lions. This research on airborne vocalizations of California sea lions will advance the understanding of this aspect of California sea lions communication, as well as examine the relationship between health condition and acoustic behavior. Using a PhillipsRTM digital recorder with attached microphone and a calibrated RadioShackRTM sound pressure level meter, acoustical data were recorded opportunistically on California sea lions during rehabilitation at The Marine Mammal Center in Sausalito, CA. Vocalizations were analyzed using frequency, time, and amplitude variables with Raven Pro: Interactive Sound Analysis Software Version 1.4 (The Cornell Lab of Ornithology, Ithaca, NY). Five frequency, three time, and four amplitude variables were analyzed for each vocalization. Differences in frequency, time, and amplitude variables were not significant by sex. The older California sea lion group produced vocalizations that were significantly lower in four frequency variables, significantly longer in two time variables, significantly higher in calibrated maximum and minimum amplitude variables, and significantly lower in frequency at maximum and minimum amplitude compared with pups. Six call types were identified: bark, goat, growl/grumble, bark/grumble, bark/growl, and grumble/moan. The growl/grumble call was higher in dominant beginning, ending, and minimum frequency, as well as in the frequency at maximum amplitude compared with the bark, goat, bark/grumble calls in the first versus last vocalization sample. The goat call was significantly higher in first harmonic interval than any other call type

  6. National Acid Precipitation Assessment Program (NAPAP) county-level alkaline emission estimates for unpaved roads. Dust Devils and wind erosion, 1985 (for microcomputers). Data file

    SciTech Connect

    Masser, C.C.; Barnard, W.R.

    1990-01-01

    The two floppy diskettes contain the data summary tables included in Appendices A, B, and C of the report Development of County-Level Wind Erosion and Unpaved Road Alkaline Emission Estimates for the 1985 NAPAP Emissions Inventory. The data tables are formatted in LOTUS 1-2-3 version 2.01 format (although they were written using Microsoft EXCEL Version 2.1). Each of the files represent one of the Appendices. It should be noted that in the report, only counties that had non-zero Dust Devil emissions were included in Appendix C. The corresponding file provides information for all counties in the continental U.S. even though most counties have Dust Devil emissions equal to zero.

  7. 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.

  8. Status and Future of Dust Storm Forecasting

    NASA Astrophysics Data System (ADS)

    Westphal, D. L.

    2002-12-01

    In recent years, increased attention has been given to the large amounts of airborne dust derived from the deserts and desertified areas of the world and transported over scales ranging from local to global. This dust can have positive and negative impacts on human activities and the environment, including modifying cloud formation, fertilizing the ocean, degrading air quality, reducing visibility, transporting pathogens, and inducing respiratory problems. The atmospheric radiative forcing by the dust has implications for global climate change and presently is one of the largest unknowns in climate models. These uncertainties have lead to much of the funding for research into the sources, properties, and fate of atmospheric dust. As a result of advances in numerical weather prediction over the past decades and the recent climate research, we are now in a position to produce operational dust storm forecasts. International organizations and national agencies are developing programs for dust forecasting. The approaches and applications of dust detection and forecasting are as varied as the nations that are developing the models. The basic components of a dust forecasting system include atmospheric forcing, dust production, and dust microphysics. The forecasting applications include air and auto traffic safety, shipping, health, national security, climate and weather. This presentation will summarize the methods of dust storm forecasting and illustrate the various applications. The major remaining uncertainties (e.g. sources and initialization) will be discussed as well as approaches for solving those problems.

  9. Levels of polybrominated diphenyl ethers in settled house dust from urban dwellings with resident preschool-aged children in Nanjing, China.

    PubMed

    Wang, Bing-Ling; Pang, Shu-tao; Zhang, Xiao-ling; Li, Xi-ling; Sun, Yong-gang; Lu, Xiao-mei; Zhang, Qi

    2015-01-01

    We investigated the levels and possible determinants of polybrominated diphenyl ethers (PBDEs) in the settled house-dust (SHD) of urban dwellings with resident preschool-aged children in Nanjing, China. The possible neurodevelopmental effects of house-dust PBDEs were also explored. SHD was collected from 216 urban houses. Levels of 8 PBDEs were measured by gas chromatography-negative chemical ionization mass spectrometry. The Child Behavior Checklist and the Gesell Development Inventory were used to evaluate the child's development. BDE47, BDE99, BDE153, BDE18, and BDE209 were detected in the SHD of >90 % of houses, of which BDE209 predominated. Most PBDEs were found at significantly greater levels in indoor than in outdoor dust (P < 0.05). Levels of BDE28 and BDE154 in houses with solid-wood floors were significantly greater than those in houses with plywood floors (P < 0.05). BDE154 levels in houses with wallpaper were significantly greater than those without wallpaper (P < 0.05). Greater BDE47 concentrations were found in houses with less natural ventilation time (linear trend P < 0.05). After dichotomization at the geometric mean concentration, BDE209 and total BDEs showed significant risks for depressed behavior problems and lower personal social developmental quotients (DQs); BDE99 and BDE153 indicated a risk for lower personal social DQs. In conclusion, PBDEs (especially BDE209) are ubiquitous in urban SHD in Nanjing residences. Natural ventilation and floor materials potentially influence PBDE levels in SHD. The potential adverse effect of postnatal exposure to PBDEs on the behavior and neurodevelopment of preschool-age children requires follow-up in larger studies. PMID:25034333

  10. Domestic exposure to fungi and total serum IgE levels in asthmatic children.

    PubMed

    Su, Huey-Jen Jenny; Wu, Pei-Chih; Lei, Huan-Yao; Wang, Jiu-Yao

    2005-08-14

    We measured the number of airborne, viable fungi and house dust mite (HDM) allergen levels in the homes of a group of asthmatic children. Blood samples were drawn and the amounts of total and specific serum IgE were determined. The association between the number of fungal colonies, dust mite allergen exposure, and specific and total IgE was evaluated. The number of viable airborne fungi was high (20,543 CFU/m(3)) in those investigated houses. Der p1 concentrations on child's mattress exceeding 2 microg/g were found in 78.6% of the houses. A quantitative dose-response relationship was demonstrated between the exposure to viable, airborne molds and the amount of total IgE (r = 0.4399 and P = .0249) and the level was further increased in children with coexposure to viable fungi and HDM. PMID:16106103

  11. Airborne asbestos in public buildings

    SciTech Connect

    Chesson, J.; Hatfield, J.; Schultz, B.; Dutrow, E.; Blake, J. )

    1990-02-01

    The U.S. Environmental Protection Agency sampled air in 49 government-owned buildings (six buildings with no asbestos-containing material, six buildings with asbestos-containing material in generally good condition, and 37 buildings with damaged asbestos-containing material). This is the most comprehensive study to date of airborne asbestos levels in U.S. public buildings during normal building activities. The air outside each building was also sampled. Air samples were analyzed by transmission electron microscopy using a direct transfer preparation technique. The results show an increasing trend in average airborne asbestos levels; outdoor levels are lowest and levels in buildings with damaged asbestos-containing material are highest. However, the measured levels and the differences between indoors and outdoors and between building categories are small in absolute magnitude. Comparable studies from Canada and the UK, although differing in their estimated concentrations, also conclude that while airborne asbestos levels may be elevated in buildings that contain asbestos, levels are generally low. This conclusion does not eliminate the possibility of higher airborne asbestos levels during maintenance or renovation that disturbs the asbestos-containing material.

  12. 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

  13. Airborne microorganisms from waste containers.

    PubMed

    Jedlicka, Sabrina S; Stravitz, David M; Lyman, Charles E

    2012-01-01

    In physician's offices and biomedical labs, biological waste is handled every day. This waste is disposed of in waste containers designed for holding red autoclave bags. The containers used in these environments are closed hands-free containers, often with a step pedal. While these containers protect the user from surface-borne microorganisms, the containers may allow airborne microorganisms to escape via the open/close mechanism because of the air current produced upon open/close cycles. In this study, the air current was shown to be sufficient to allow airborne escape of microorganisms held in the container, including Aspergillus niger. However, bacterial cultures, such as Escherichia coli and Lactococcus lactis did not escape. This may be due to the choice of bacterial cultures and the absence of solid waste, such as dust or other particulate matter in the waste containers, that such strains of bacteria could travel on during aerosolization. We compared these results to those obtained using a re-designed receptacle, which mimimizes air currents, and detected no escaping microorganisms. This study highlights one potential source of airborne contamination in labs, hospitals, and other environments that dispose of biological waste. PMID:23047084

  14. Fennec dust forecast intercomparison over the Sahara in June 2011

    NASA Astrophysics Data System (ADS)

    Chaboureau, Jean-Pierre; Flamant, Cyrille; Dauhut, Thibaut; Kocha, Cécile; Lafore, Jean-Philippe; Lavaysse, Chistophe; Marnas, Fabien; Mokhtari, Mohamed; Pelon, Jacques; Reinares Martínez, Irene; Schepanski, Kerstin; Tulet, Pierre

    2016-06-01

    In the framework of the Fennec international programme, a field campaign was conducted in June 2011 over the western Sahara. It led to the first observational data set ever obtained that documents the dynamics, thermodynamics and composition of the Saharan atmospheric boundary layer (SABL) under the influence of the heat low. In support to the aircraft operation, four dust forecasts were run daily at low and high resolutions with convection-parameterizing and convection-permitting models, respectively. The unique airborne and ground-based data sets allowed the first ever intercomparison of dust forecasts over the western Sahara. At monthly scale, large aerosol optical depths (AODs) were forecast over the Sahara, a feature observed by satellite retrievals but with different magnitudes. The AOD intensity was correctly predicted by the high-resolution models, while it was underestimated by the low-resolution models. This was partly because of the generation of strong near-surface wind associated with thunderstorm-related density currents that could only be reproduced by models representing convection explicitly. Such models yield emissions mainly in the afternoon that dominate the total emission over the western fringes of the Adrar des Iforas and the Aïr Mountains in the high-resolution forecasts. Over the western Sahara, where the harmattan contributes up to 80 % of dust emission, all the models were successful in forecasting the deep well-mixed SABL. Some of them, however, missed the large near-surface dust concentration generated by density currents and low-level winds. This feature, observed repeatedly by the airborne lidar, was partly forecast by one high-resolution model only.

  15. Effects of airborne particulate matter on the acidity of precipitation in central Missouri

    SciTech Connect

    Applin, K.R.

    1985-01-01

    The pH of rainfall in central Missouri was monitored at four sites during the fall of 1983. Several pH values were well above 5.6, the theoretical pH of pure water in equilibrium with ambient levels of CO/sub 2/. Most of the higher pH's were measured on rainfall of short duration or rainfall collected during the first few hours of extended rainfall events. Furthermore, the rainfall associated with storm events lasting several days exhibited a trend of decreasing pH with time approaching values as low as 4.0 during the late stages of rainfall. Precipitation pH values above 5.6 apparently reflect neutralization reactions between wet precipitation and various components of airborne dust, especially clays and carbonates. During extended rainfalls, the neutralization effects gradually diminish as suspended dust is washed from the atmosphere yielding more accurate values of the wet precipitation pH. The results of this study suggest that airborne particulate matter generated from the dust bowl region of the US may affect the chemistry of precipitation in areas hundreds of kilometers downwind. Using date available in the literature, a direct relationship between precipitation pH and accumulated dustfall was found for data taken along a transect which represents the path of major storms crossing the US, i.e., from the south-central to northeastern regions.

  16. Ventilatory function in workers exposed to tea and wood dust.

    PubMed Central

    Al Zuhair, Y S; Whitaker, C J; Cinkotai, F F

    1981-01-01

    Changes in ventilatory capacity during the work shift were studied in workers exposed to tea dust in tea-packing plants, wood dust in two furniture factories, and virtually no dust in an inoperational power station. The FEV1 and FVC in workers exposed to dust were found to decline during the work shift by a small but significant volume. The MMFR, Vmax 50% and Vmax 75% were to variable to display any trend. No dose-response relationship could be discerned between the fall in workers' ventilatory capacity and the concentrations of airborne dust or microbes to which they were exposed. Bronchodilators could reverse the fall in FEV1. PMID:7317296

  17. The effects of meteorological factors on airborne fungal spore concentration in two areas differing in urbanisation level

    NASA Astrophysics Data System (ADS)

    Oliveira, M.; Ribeiro, H.; Delgado, J. L.; Abreu, I.

    2009-01-01

    Although fungal spores are an ever-present component of the atmosphere throughout the year, their concentration oscillates widely. This work aims to establish correlations between fungal spore concentrations in Porto and Amares and meteorological data. The seasonal distribution of fungal spores was studied continuously (2005-2007) using volumetric spore traps. To determine the effect of meteorological factors (temperature, relative humidity and rainfall) on spore concentration, the Spearman rank correlation test was used. In both locations, the most abundant fungal spores were Cladosporium, Agaricus, Agrocybe, Alternaria and Aspergillus/Penicillium, the highest concentrations being found during summer and autumn. In the present study, with the exception of Coprinus and Pleospora, spore concentrations were higher in the rural area than in the urban location. Among the selected spore types, spring-autumn spores ( Coprinus, Didymella, Leptosphaeria and Pleospora) exhibited negative correlations with temperature and positive correlations both with relative humidity and rainfall level. On the contrary, late spring-early summer (Smuts) and summer spores ( Alternaria, Cladosporium, Epicoccum, Ganoderma, Stemphylium and Ustilago) exhibited positive correlations with temperature and negative correlations both with relative humidity and rainfall level. Rust, a frequent spore type during summer, had a positive correlation with temperature. Aspergillus/Penicillium, showed no correlation with the meteorological factors analysed. This knowledge can be useful for agriculture, allowing more efficient and reliable application of pesticides, and for human health, by improving the diagnosis and treatment of respiratory allergic disease.

  18. Modeling and Remote Sensing for a Dust/Health Early Warning System

    NASA Astrophysics Data System (ADS)

    Sprigg, W. A.

    2015-12-01

    Airborne desert dust is a human health problem in much of the world. While controlling emissions from arid lands is problematic, advances in remote sensing and modeling have matured sufficiently to reduce risks of exposure. Active dust sources are identified and monitored from space-based platforms and from modeled back-trajectories. Satellite-based sensors detect and monitor airborne dust crossing oceans and circling the globe. High-resolution dust forecasts and simulations over the U.S. southwest have been successfully demonstrated. Operational dust forecast systems could warn of intercontinental dust movements and potential dust exposure hazards on spatial scales of a few kilometers and on time scales sufficient for planning and avoiding risks. This paper will show how the World Meteorological Organization's Sand and Dust Storm Warning Advisory and Assessment System could coordinate international collaboration for a worldwide Dust/Health Early Warning System modeled after the decades-long success of the international Famine Early Warning System.

  19. Protoplanetary Dust

    NASA Astrophysics Data System (ADS)

    Apai, Dániel; Lauretta, Dante S.

    2010-01-01

    Preface; 1. Planet formation and protoplanetary dust Daniel Apai and Dante Lauretta; 2. The origins of protoplanetary dust and the formation of accretion disks Hans-Peter Gail and Peter Hope; 3. Evolution of protoplanetary disk structures Fred Ciesla and Cornelius P. Dullemond; 4. Chemical and isotopic evolution of the solar nebula and protoplanetary disks Dmitry Semenov, Subrata Chakraborty and Mark Thiemens; 5. Laboratory studies of simple dust analogs in astrophysical environments John R. Brucato and Joseph A. Nuth III; 6. Dust composition in protoplanetaty dust Michiel Min and George Flynn; 7. Dust particle size evolution Klaus M. Pontoppidan and Adrian J. Brearly; 8. Thermal processing in protoplanetary nebulae Daniel Apai, Harold C. Connolly Jr. and Dante S. Lauretta; 9. The clearing of protoplanetary disks and of the protosolar nebula Ilaira Pascucci and Shogo Tachibana; 10. Accretion of planetesimals and the formation of rocky planets John E. Chambers, David O'Brien and Andrew M. Davis; Appendixes; Glossary; Index.

  20. Protoplanetary Dust

    NASA Astrophysics Data System (ADS)

    Apai, D.´niel; Lauretta, Dante S.

    2014-02-01

    Preface; 1. Planet formation and protoplanetary dust Daniel Apai and Dante Lauretta; 2. The origins of protoplanetary dust and the formation of accretion disks Hans-Peter Gail and Peter Hope; 3. Evolution of protoplanetary disk structures Fred Ciesla and Cornelius P. Dullemond; 4. Chemical and isotopic evolution of the solar nebula and protoplanetary disks Dmitry Semenov, Subrata Chakraborty and Mark Thiemens; 5. Laboratory studies of simple dust analogs in astrophysical environments John R. Brucato and Joseph A. Nuth III; 6. Dust composition in protoplanetaty dust Michiel Min and George Flynn; 7. Dust particle size evolution Klaus M. Pontoppidan and Adrian J. Brearly; 8. Thermal processing in protoplanetary nebulae Daniel Apai, Harold C. Connolly Jr. and Dante S. Lauretta; 9. The clearing of protoplanetary disks and of the protosolar nebula Ilaira Pascucci and Shogo Tachibana; 10. Accretion of planetesimals and the formation of rocky planets John E. Chambers, David O'Brien and Andrew M. Davis; Appendixes; Glossary; Index.

  1. Characterisation of airborne particles collected within and proximal to an opencast coalmine: South Wales, U.K.

    PubMed

    Jones, Tim; Blackmore, Pete; Leach, Matt; Bérubé, Kelly; Sexton, Keith; Richards, Roy

    2002-05-01

    Airborne particulate matter has been collected from within, and proximal to, an opencast coal mine in south Wales. This work forms the first part of a three year project to collect and characterise, then determine the possible toxicology of airborne particles in the south Wales region. High-resolution Field Emission SEM has shown that the coal mine dusts consist largely of an assemblage of mineral grains and vehicle exhaust particles. SEM-EDX has shown that the mineralogical make-up of the PM10 is complex, heterogeneous, and constantly changing. These findings are supported by analytical TEM-EPXMA. However, patterns can be determined relating the mineralogical composition of the airborne particles to collection locations and mining activities within the opencast. At our study opencast, Park Slip West, quartz, which has known health effects, never exceeded 30% of the total collection mass, and average levels were much less. Vehicle exhaust emissions was the largest source in terms of particle numbers. The mass of airborne particulate matter within the pit averaged approximately twice that of outside the pit: importantly however, this higher mass was due to relatively large, and non-respirable, mineral grains. This study demonstrates that the physicochemical and mineralogical characterisation of airborne particles from mining and quarrying is essential to quantify the respirable fraction, and to identify potentially hazardous components within the PM10. PMID:12004982

  2. The global transport of dust

    USGS Publications Warehouse

    Griffin, Dale W.; Kellogg, C.A.; Garrison, V.H.; Shinn, E.A.

    2002-01-01

    By some estimates as much as two billion metric tons of dust are lifted into the Earth's atmosphere every year. Most of this dust is stirred up by storms, the more dramatic of which are aptly named dust storms. But more than mere dirt is carried aloft. Drifting with the suspended dust particles are soil pollutants such as herbicides and pesticides and a significant number of microorganisms-bacteria, viruses and fungi. We can gain some appreciation of how much microbial life is actually floating in our atmosphere by performing a quick calculation. There are typically about one million bacteria per gram of soil, but let's be conservative and suppose there are only 10,000 bacteria per gram of airborne sediment. Assuming a modest one billion metric tons of sediment in the atmosphere, these numbers translate into a quintillion (1018) sediment-borne bacteria moving around the planet each year-enough to form a microbial bridge between Earth and Jupiter. Here we consider what we've learned about the airborne transport of sediment across the globe, and review some of the remarkable studies in this reemerging field that had it origins more than 100 years ago.

  3. Optical dust sensor for the mining industry

    NASA Astrophysics Data System (ADS)

    Sierakowski, Marek W.; Wolinski, Tomasz R.; Domanski, Andrzej W.; Osinska, Katarzyna

    2003-04-01

    One of many hazards in mining industry is presence of airborne dust on underground boards. Hazards caused by dust generated and spread in mines are of the two types: (1) health risk for miners from airborne dust produced from rocks, coal, soluble minerals (pneumoconiosis, toxicity), (2) danger of explosion of carbon dust. Dust particles produced in mines underground range from 0 to about 400 micrometers, have irregular shapes and prevailingly are strongly light absorbing. It is assumed that the most health-risky are particles between 1 μm and 5 μm in size. They are not visible with naked eyes, so their control and measurement need technical equipment. As a standard in polish mines, gravimetric measurement method is used at present. This method works well in post-event evaluation of total health-risk factor, but is not much useful for instantaneous risk warning. In order to recognize and possibly prevent the dust risk as it appears, other methods have to be used, like optical method. Looking towards this demand, an experimental optical dust sensor is demonstrated. The sensor is based on light scattering effect by dust particles, as usual do devices of this type. Originality of this solution lies in construction details of the sensor. Scattering is a complex function of dust kind, size, shape and concentration. Moreover, operating conditions of such a device are cruel -- humidity, elevated temperature, vibrations, and over-all contact with dust -- are harmful for optics. Thus, to achieve reliable indications of the sensor is really a challenge. This paper describes optical construction attempting to overcome difficulties in obtaining dust concentration sensor intended for mining industry and similar applications. First laboratory and operational tests are also reported.

  4. Saharan dust aerosol over the central Mediterranean Sea: optical columnar measurements vs. aerosol load, chemical composition and marker solubility at ground level

    NASA Astrophysics Data System (ADS)

    Marconi, M.; Sferlazzo, D. M.; Becagli, S.; Bommarito, C.; Calzolai, G.; Chiari, M.; di Sarra, A.; Ghedini, C.; Gómez-Amo, J. L.; Lucarelli, F.; Meloni, D.; Monteleone, F.; Nava, S.; Pace, G.; Piacentino, S.; Rugi, F.; Severi, M.; Traversi, R.; Udisti, R.

    2013-08-01

    average aerosol optical depth at 495.7 nm up to 0.28 in June-August). We found that 71.3% of the events identified from optical properties over the air column display a high dust content at the ground level. Conversely, the remaining 28.7% of cases present a negligible or small impact of dust on the surface aerosol composition due to the Saharan dust transport processes over the Mediterranean that frequently occur above the marine boundary layer especially in spring, summer and early autumn. The solubility of different elements presents a large variability. In general, the solubility is lower in Saharan dust samples than for non-Saharan dust events. The solubility also displays a marked dependency on size for Saharan dust samples. Crustal markers show two relative maxima in the size range 2.1-3.3 μm and 5.8-9 μm, generally characterized by low solubility. Optical particle counter measurements present similar values of median radii for the dust size distribution. Conversely, elements mainly due to anthropic sources display a maximum in the finest fraction, and a high solubility. For instance, Fe, K, and Co present a very low solubility in the coarse fraction (8% in the size range 2.1-3.3 μm for Fe), while the finest fraction is characterized by high solubility (69% in the size range 0.4-0.7 μm for Fe). A ionic balance analysis on multi-stage impactor samples shows that exchange reactions involving anthropic acids, and crustal matter may play a significant role in cases of mixing. These reactions may affect the solubility and bioavailability of the crustal elements.

  5. Dust Emission Induced By Friction Modifications At Tool Chip Interface In Dry Machining In MMCp

    NASA Astrophysics Data System (ADS)

    Kremer, Arnaud; El Mansori, Mohamed

    2011-01-01

    This paper investigates the relationship between dust emission and tribological conditions at the tool-chip interface when machining Metal Matrix composite reinforced with particles (MMCp) in dry mode. Machining generates aerosols that can easily be inhaled by workers. Aerosols may be composed of oil mist, tool material or alloying elements of workpiece material. Bar turning tests were conducted on a 2009 aluminum alloy reinforced with different level of Silicon Carbide particles (15, 25 and 35% of SiCp). Variety of PCD tools and nanostructured diamond coatings were used to analyze their performances on air pollution. A spectrometer was used to detect airborne aerosol particles in the size range between 0.3μm to 20 μm and to sort them in 15 size channels in real time. It was used to compare the effects of test parameters on dust emission. Observations of tool face and chip morphology reveal the importance of friction phenomena. It was demonstrated that level of friction modifies chip curvature and dust emission. The increase of level of reinforcement increase the chip segmentation and decrease the contact length and friction area. A "running in" phenomenon with important dust emission appeared with PCD tool due to the tool rake face flatness. In addition dust generation is more sensitive to edge integrity than power consumption.

  6. Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA

    PubMed Central

    Goossens, Dirk

    2015-01-01

    Elevated concentrations of arsenic, up to 7058 μg g-1 in topsoil and bedrock, and more than 0.03 μg m-3 in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m-3. The results of this study are important because the NDRA is visited by more than 300,000 people annually. PMID:25897667

  7. On the Characterization of the Generation Rate and Size-Dependent Crystalline Silica Content of the Dust from Cutting Fiber Cement Siding.

    PubMed

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

    2016-03-01

    A laboratory testing system was developed to systematically characterize the dust generation rate and size-dependent crystalline silica content when cutting or shaping silica containing materials. The tests of cutting fiber cement siding in this system verify that it provides high test repeatability, making it suitable for the targeted characterizations. The mass-based size distributions obtained from a gravimetric-based instrument and a direct reading instrument both show bimodal lognormal distributions with a larger mode ~13 µm and another mode <5 µm for the dusts from cutting four different brands of fiber cement siding. The generation rates of respirable dust obtained from the two instruments are comparable, and the results from each instrument are similar for the four brands. The silica content in the airborne dusts, however, strongly depends on the amount of silica used in the respective product. It is also observed that the silica content in the airborne dust from cutting the four brands of fiber cement siding showed the same trend of an increase with the aerodynamic diameter of the dust, approaching the silica content levels found in their respective bulk samples. Combining the results for both the dust size distribution and size-dependent silica content, it is found that most of the respirable crystalline silica (RCS) resides in the dust ~2.5 µm in aerodynamic diameter. These results would help guide the development of specific engineering control measures targeted at lowering workers' exposure to RCS while cutting fiber cement siding. With the high repeatability using the laboratory testing system, the dust generation rate could then be characterized under different operating conditions, and with the deployment of various engineering control measures. This would greatly facilitate the systematic evaluation of the control effectiveness and the selection of the optimal control solutions for field trials. PMID:26391971

  8. Application of a Broad-Range Resequencing Array for Detection of Pathogens in Desert Dust Samples from Kuwait and Iraq ▿

    PubMed Central

    Leski, Tomasz A.; Malanoski, Anthony P.; Gregory, Michael J.; Lin, Baochuan; Stenger, David A.

    2011-01-01

    A significant percentage of the human population is exposed to high levels of naturally occurring airborne dusts. Although the link between airborne particulate inhalation and a variety of respiratory diseases has long been established, little is known about the pathogenic role of the microbial component of the dust. In this study, we applied highly multiplexed PCR and a high-density resequencing microarray (RPM-TEI version 1.0) to screen samples of fine topsoil particles and airborne dust collected in 19 locations in Iraq and Kuwait for the presence of a broad range of human pathogens. The results indicated the presence of potential human pathogens, including Mycobacterium, Brucella, Coxiella burnetii, Clostridium perfringens, and Bacillus. The presence of Coxiella burnetii, a highly infectious potential biowarfare agent, was confirmed and detected in additional samples by use of a more sensitive technique (real-time PCR), indicating a high prevalence of this organism in the analyzed samples. The detection of potentially viable pathogens in breathable dusts from arid regions of Iraq and Kuwait underscores the importance of further study of these environments. PMID:21571877

  9. Viability and potential for immigration of airborne bacteria from Africa that reach high mountain lakes in Europe.

    PubMed

    Hervàs, Anna; Camarero, Lluís; Reche, Isabel; Casamayor, Emilio O

    2009-06-01

    We have analysed the diversity of the bacteria, which grow after addition of concentrated airborne particles and desert dust in different microcosms combinations with water samples from oligotrophic alpine lakes. We used, on the one hand, airborne bacteria transported by an African dust plume and collected in a high mountain area in the central Pyrenees (Spain). On the other hand, we collected desert dust in Mauritania (c. 3000 km distance, and a few days estimated airborne journey), a known source region for dust storms in West Africa, which originates many of the dust plumes landing on Europe. In all the dust-amended treatments we consistently observed bacterial growth of common phyla usually found in freshwater ecosystems, i.e. Alpha-, Beta- and Gammaproteobacteria, Actinobacteria, and a few Bacteroidetes, but with different composition based on lake water pretreatment and dust type. Overall, we tentatively split the bacterial community in (i) typical freshwater non-airborne bacteria, (ii) cosmopolitan long-distance airborne bacteria, (iii) non-freshwater low-distance airborne bacteria, (iv) non-freshwater long-distance airborne soil bacteria and (v) freshwater non-soil airborne bacteria. We identified viable long-distance airborne bacteria as immigrants in alpine lakes (e.g. Sphingomonas-like) but also viable putative airborne pathogens with the potential to grow in remote alpine areas (Acinetobacter-like and Arthrobacter-like). Generation of atmospheric aerosols and remote dust deposition is a global process, largely enhanced by perturbations linked to the global change, and high mountain lakes are very convenient worldwide model systems for monitoring global-scale bacterial dispersion and pathogens entries in remote pristine environments. PMID:19453609

  10. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    ... contrast strongly with the dust storm that swept across Iraq and Saudi Arabia on May 13, 2004 (bottom panels). These data products from ... as yellowish ripples that obscure a large part of southern Iraq. The dust is easy to discern over the dark waters of the teardrop-shaped ...

  11. Rocket dust storms and detached dust layers in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Spiga, Aymeric; Faure, Julien; Madeleine, Jean-Baptiste; Määttänen, Anni; Forget, François

    2013-04-01

    Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling that includes the transport of radiatively active dust to predict the evolution of a local dust storm monitored by OMEGA on board Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, rather than by latent heating as in moist convection on Earth. We propose to use the terminology "rocket dust storm," or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30-50 km). Combined to horizontal transport by large-scale winds, rocket dust storms produce detached layers of dust reminiscent of those observed with Mars Global Surveyor and Mars Reconnaissance Orbiter. Since nighttime sedimentation is less efficient than daytime convective transport, and the detached dust layers can convect during the daytime, these layers can be stable for several days. The peak activity of rocket dust storms is expected in low-latitude regions at clear seasons (late northern winter to late northern summer), which accounts for the high-altitude tropical dust maxima unveiled by Mars Climate Sounder. Dust-driven deep convection has strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.

  12. Andromeda's dust

    SciTech Connect

    Draine, B. T.; Aniano, G.; Krause, Oliver; Groves, Brent; Sandstrom, Karin; Klaas, Ulrich; Linz, Hendrik; Rix, Hans-Walter; Schinnerer, Eva; Schmiedeke, Anika; Walter, Fabian; Braun, Robert; Leroy, Adam E-mail: ganiano@ias.u-psud.fr

    2014-01-10

    Spitzer Space Telescope and Herschel Space Observatory imaging of M31 is used, with a physical dust model, to construct maps of dust surface density, dust-to-gas ratio, starlight heating intensity, and polycyclic aromatic hydrocarbon (PAH) abundance, out to R ≈ 25 kpc. The global dust mass is M {sub d} = 5.4 × 10{sup 7} M {sub ☉}, the global dust/H mass ratio is M {sub d}/M {sub H} = 0.0081, and the global PAH abundance is (q {sub PAH}) = 0.039. The dust surface density has an inner ring at R = 5.6 kpc, a maximum at R = 11.2 kpc, and an outer ring at R ≈ 15.1 kpc. The dust/gas ratio varies from M {sub d}/M {sub H} ≈ 0.026 at the center to ∼0.0027 at R ≈ 25 kpc. From the dust/gas ratio, we estimate the interstellar medium metallicity to vary by a factor ∼10, from Z/Z {sub ☉} ≈ 3 at R = 0 to ∼0.3 at R = 25 kpc. The dust heating rate parameter (U) peaks at the center, with (U) ≈ 35, declining to (U) ≈ 0.25 at R = 20 kpc. Within the central kiloparsec, the starlight heating intensity inferred from the dust modeling is close to what is estimated from the stars in the bulge. The PAH abundance reaches a peak q {sub PAH} ≈ 0.045 at R ≈ 11.2 kpc. When allowance is made for the different spectrum of the bulge stars, q {sub PAH} for the dust in the central kiloparsec is similar to the overall value of q {sub PAH} in the disk. The silicate-graphite-PAH dust model used here is generally able to reproduce the observed dust spectral energy distribution across M31, but overpredicts 500 μm emission at R ≈ 2-6 kpc, suggesting that at R = 2-6 kpc, the dust opacity varies more steeply with frequency (with β ≈ 2.3 between 200 and 600 μm) than in the model.

  13. Interactions Between Mineral Dust, Climate, and Ocean Ecosystems

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  14. Evaporative Cooler Use Influences Temporal Indoor Relative Humidity but Not Dust Mite Allergen Levels in Homes in a Semi-Arid Climate.

    PubMed

    Johnston, James D; Tuttle, Steven C; Nelson, Morgan C; Bradshaw, Rebecca K; Hoybjerg, Taylor G; Johnson, Julene B; Kruman, Bryce A; Orton, Taylor S; Cook, Ryan B; Eggett, Dennis L; Weber, K Scott

    2016-01-01

    Concerns about energy consumption and climate change make residential evaporative coolers a popular alternative to central air conditioning in arid and semi-arid climates. However, evaporative coolers have been shown to significantly increase indoor relative humidity and dust mite allergen levels in some studies, while showing no association in other studies. Improved measurement of temporal fluctuations in indoor relative humidity may help identify factors that promote mite growth in homes in dry climates. Dust samples and continuous indoor relative humidity measurements were collected from homes with central air conditioning and homes with evaporative coolers in Utah. Samples were collected over two seasons, winter/spring (Jan-Apr) and summer (July-Sept), 2014. Dust samples were analyzed for Der p 1 and Der f 1 using a two-site monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) analysis. Housing characteristics including age of home, occupant density, and age of mattresses, furniture, and carpeting were also measured. Positive Der p 1 or Der f 1 samples were found in 25.0% of the homes and there was no difference in mean allergen levels by type of air conditioning. Indoor relative humidity was significantly higher in homes with evaporative coolers compared to those with central air conditioning during the summer. Homes with evaporative coolers also spent significantly more time during summer above 55.0% and 65.0% relative humidity compared to central air homes, but not above 75.0%. Findings from this study suggest that increased humidity from evaporative coolers may not be sufficient to exceed the critical equilibrium humidity or maintain humidity excursions for sufficient duration in relatively larger single-family homes in semi-arid climates to support mite growth and reproduction. PMID:26808528

  15. Evaporative Cooler Use Influences Temporal Indoor Relative Humidity but Not Dust Mite Allergen Levels in Homes in a Semi-Arid Climate

    PubMed Central

    Johnston, James D.; Tuttle, Steven C.; Nelson, Morgan C.; Bradshaw, Rebecca K.; Hoybjerg, Taylor G.; Johnson, Julene B.; Kruman, Bryce A.; Orton, Taylor S.; Cook, Ryan B.; Eggett, Dennis L.; Weber, K. Scott

    2016-01-01

    Concerns about energy consumption and climate change make residential evaporative coolers a popular alternative to central air conditioning in arid and semi-arid climates. However, evaporative coolers have been shown to significantly increase indoor relative humidity and dust mite allergen levels in some studies, while showing no association in other studies. Improved measurement of temporal fluctuations in indoor relative humidity may help identify factors that promote mite growth in homes in dry climates. Dust samples and continuous indoor relative humidity measurements were collected from homes with central air conditioning and homes with evaporative coolers in Utah. Samples were collected over two seasons, winter/spring (Jan–Apr) and summer (July–Sept), 2014. Dust samples were analyzed for Der p 1 and Der f 1 using a two-site monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) analysis. Housing characteristics including age of home, occupant density, and age of mattresses, furniture, and carpeting were also measured. Positive Der p 1 or Der f 1 samples were found in 25.0% of the homes and there was no difference in mean allergen levels by type of air conditioning. Indoor relative humidity was significantly higher in homes with evaporative coolers compared to those with central air conditioning during the summer. Homes with evaporative coolers also spent significantly more time during summer above 55.0% and 65.0% relative humidity compared to central air homes, but not above 75.0%. Findings from this study suggest that increased humidity from evaporative coolers may not be sufficient to exceed the critical equilibrium humidity or maintain humidity excursions for sufficient duration in relatively larger single-family homes in semi-arid climates to support mite growth and reproduction. PMID:26808528

  16. The Fate of Saharan Dust Across the Atlantic and Implications for a Central American Dust Barrier

    NASA Technical Reports Server (NTRS)

    Nowottnick, E.; Colarco, P.; da Silva, A.; Hlavka, D.; McGill, M.

    2011-01-01

    Saharan dust was observed over the Caribbean basin during the summer 2007 NASA Tropical Composition, Cloud, and Climate Coupling (TC4) field experiment. Airborne Cloud Physics Lidar (CPL) and satellite observations from MODIS suggest a barrier to dust transport across Central America into the eastern Pacific. We use the NASA GEOS-5 atmospheric transport model with online aerosol tracers to perform simulations of the TC4 time period in order to understand the nature of this barrier. Our simulations are driven by the Modem Era Retrospective-Analysis for Research and Applications (MERRA) meteorological analyses. We evaluate our baseline simulated dust distributions using MODIS and CALIOP satellite and ground-based AERONET sun photometer observations. GEOS-5 reproduces the observed location, magnitude, and timing of major dust events, but our baseline simulation does not develop as strong a barrier to dust transport across Central America as observations suggest. Analysis of the dust transport dynamics and lost processes suggest that while both mechanisms play a role in defining the dust transport barrier, loss processes by wet removal of dust are about twice as important as transport. Sensitivity analyses with our model showed that the dust barrier would not exist without convective scavenging over the Caribbean. The best agreement between our model and the observations was obtained when dust wet removal was parameterized to be more aggressive, treating the dust as we do hydrophilic aerosols.

  17. Measurements of the effectiveness of dust control on cut-off saws used in the construction industry.

    PubMed

    Thorpe, A; Ritchie, A S; Gibson, M J; Brown, R C

    1999-10-01

    Materials used in the construction industry frequently contain large quantities of silica. When they are cut or shaped with power tools considerable respirable dust can be produced. Three dust control systems for use with cut-off saws have been evaluated on site: wet dust suppression using mains water, the same system using water from a portable water tank, and local exhaust ventilation. The efficiency of water suppression on cut-off saws has been precisely quantified in controlled laboratory conditions by means of measurements with and without dust control. When dust control was used on-site, the mean concentrations of airborne silica were reduced by a factor of between three and seven, the accuracy being limited by the relatively high limit of detection for silica. All controls systems generally reduced respirable dust levels by at least 90%. Although the effectiveness of dust suppression did not depend on blade type, a diamond blade was more effective than a resin-bonded blade with the pressurised water system; cutting a slab with this type of blade could be completed before the water tank required repressurization. In laboratory tests, the application of water reduced the dust concentration to < 4% of its value without control. The method for monitoring the dust concentration was sufficiently sensitive to measure a difference in concentration produced during cutting in different directions. It is important, however, that the pressure in supply reservoirs is properly maintained, that the water is correctly applied and that it is used at the correct rate. If this is done effective dust control can be achieved. PMID:10582028

  18. Atmospheric aging of dust ice nucleating particles - a combined laboratory and field approach

    NASA Astrophysics Data System (ADS)

    Boose, Yvonne; Rodríguez, Sergio; García, M. Isabel; Linke, Claudia; Schnaiter, Martin; Zipori, Assaf; Crawford, Ian; Lohmann, Ulrike; Kanji, Zamin A.; Sierau, Berko

    2016-04-01

    We present INP data measured in-situ at two mostly free tropospheric locations: the High Altitude Research Station Jungfraujoch (JFJ) in the Swiss Alps, located at 3580 m above sea level (asl) and the Izaña observatory on Tenerife, off the West African shore (2373 m asl). INP concentrations were measured online with the Portable Ice Nucleation Chamber, PINC, at the Jungfraujoch in the winters of 2012, 2013 and 2014 and at Izaña in the summers of 2013 and 2014. Each measurement period lasted between 2 to 6 weeks. During summer, Izaña is frequently within the Saharan Air Layer and thus often exposed to Saharan dust events. Saharan dust also reaches the Jungfraujoch mainly during spring. For offline ice nucleation analysis in the laboratory under similar thermodynamic conditions, airborne dust was collected a) at Izaña with a cyclone directly from the air and b) collected from the surface of the Aletsch glacier close to the JFJ after deposition. Supporting measurements of aerosol particle size distributions and fluorescence were conducted at both locations, as well as cloud water isotope analysis at the Jungfraujoch and aerosol chemistry at Izaña. For both locations the origin of the INPs was investigated with a focus on dust and biological particles using back trajectories and chemical signature. Results show that dust aerosol is the dominant INP type at both locations at a temperature of 241 K. In addition to Saharan dust, also more local, basaltic dust is found at the Jungfraujoch. Biological particles are not observed to play a role for ice nucleation in clouds during winter at Jungfraujoch but are enriched in INP compared to the total aerosol at Izaña also during dust events. The comparison of the laboratory and the field measurements at Izaña indicates a good reproducibility of the field data by the collected dust samples. Field and laboratory data of the dust samples from both locations show that the dust arriving at JFJ is less ice nucleation active

  19. Level and Contamination Assessment of Environmentally Sensitive Elements in Smaller than 100 μm Street Dust Particles from Xining, China

    PubMed Central

    Zhao, Ni; Lu, Xinwei; Chao, Shigang

    2014-01-01

    Concentrations of the environmentally sensitive elements (ESEs) As, Co, Cu, Mn, Ni, Pb, V and Zn in smaller than 100 μm street dust particles from Xining were measured using X-ray fluorescence spectrometry and their contamination levels were assessed based on enrichment factor (EF), geoaccumulation index (Igeo) and pollution load index (PLI). The concentrations of As, Co, Cu, Mn, Ni, Pb, V and Zn in smaller than 100 μm street dust particles from Xining are 0.1–0.8, 2.7–10.9, 0.7–5.2, 0.3–1.1, 0.6–2.5, 1.2–11.1, 0.7–1.3 and 0.4–2.9 times the background values of Qinghai soil, respectively. The calculated EF and Igeo values reveal the order Co > Pb > Cu > Zn > V > Ni > Mn > As. The EF and Igeo values of Co, Cu, Pb and Zn are higher indicating that there is considerable pollution by these elements in smaller than 100 μm street dust particles, especially for Co. The EF and Igeo of Mn, Ni and V are lower and the assessment results indicate an absence of distinct Mn, Ni and V pollution in the studied samples. The mean value of PLIsite is 1.14, indicating a slightly pollution in the whole city of Xining. The order of PLIarea for the five tested districts is Center District (CD) > East District (ED) > West District (WD) > North District (ND) > South District (SD), showing that ESEs pollution in the South District is the lightest while it is the highest in the Central District. PMID:24590050

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

    PubMed

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

    2015-12-01

    Although approximately 123 million people may be exposed to high levels of insecticides through the use of indoor residual spraying (IRS) for malaria control, few studies exist on indoor insecticide contamination due to IRS and its relationship with human exposure. In the present study, we developed a sampling method to collect undisturbed dust from 50 homes in Limpopo, South Africa, a region where dichlorodiphenyltrichloroethane (DDT) has been used in IRS programs to prevent malaria for ~70years. We quantified DDT and its degradation products, dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyldichloroethane (DDD) in dust samples to determine dust loading levels and compared these levels to paired serum concentrations of p,p'-DDT and p,p'-DDE in women residents. p,p'-DDT and p,p'-DDE had the highest detection frequencies in both dust (58% and 34% detection, respectively) and serum samples (98% and 100% detection, respectively). Significantly higher detection frequencies for o,p'-DDT, p,p'-DDE, and p,p'-DDD were observed in dust samples collected in buildings that had been previously sprayed for malaria control. We also observed a significant, positive association between dust loading and serum concentrations of p,p'-DDT and p,p'-DDE (Spearman's rho=0.68 and 0.54, respectively). Despite the low detection frequency in dust, our results indicate that undisturbed dust may be a good metric to quantify long-term home exposure to DDT-related compounds and that contamination of the home environment may be an important determinant/source of DDT and DDE exposure. PMID:26398044

  1. THE AIRBORNE CULTURABLE MICROBIAL ECOLOGY OF SEVEN FEEDYARDS IN THE HIGH PLAINS OF TEXAS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concentrated animal feeding operations (CAFO) produce a large amount of manure that can impact the environment if not managed properly. Environmental issues at CAFO include odor, pathogens, endotoxins (ET), and dust. The role of ET and pathogens with dust emissions was investigated. Airborne microbi...

  2. Evidence for dust transport in Viking IR thermal mapper opacity data

    NASA Technical Reports Server (NTRS)

    Martin, Terry Z.

    1993-01-01

    Global maps of 9-micron dust opacity derived from radiometric observations made by the Viking Orbiter IR Thermal Mapper instruments have revealed a wealth of new information about the distribution of airborne dust over 1.36 Mars years from 1976-1979. In particular, the changing dust distribution during major dust storms is of interest since the data provide a point of contact with both Earth-based observations of storm growth and with global circulation models.

  3. Exozodiacal dust

    NASA Astrophysics Data System (ADS)

    Kuchner, Marc Jason

    Besides the sun, the most luminous feature of the solar system is a cloud of "zodiacal" dust released by asteroids and comets that pervades the region interior to the asteroid belt. Similar clouds of dust around other stars---exozodiacal clouds---may be the best tracers of the habitable zones of extra-solar planetary systems. This thesis discusses three searches for exozodiacal dust: (1) We observed six nearby main-sequence stars with the Keck telescope at 11.6 microns, correcting for atmosphere-induced wavefront aberrations and deconvolving the point spread function via classical speckle analysis. We compare our data to a simple model of the zodiacal dust in our own system based on COBE DIRBE observations and place upper limits on the density of exozodiacal dust in these systems. (2) We observed Sirius, Altair, and Procyon with the NICMOS Coronagraph on the Hubble Space Telescope to look for scattered light from exozodiacal dust and faint companions within 10 AU from these stars. (3) The planned nulling capability of the Keck Interferometer should allow it to probe the region <200 milliarcsecond from a bright star and to suppress on-axis starlight by factors of 10 -3 to reveal faint circumstellar material. We model the response of the Keck Interferometer to hypothetical exozodiacal clouds to derive detection limits that account for the effects of stellar leakage, photon noise, noise from null depth fluctuations, and the fact that the cloud's shape is not known a priori. We also discuss the interaction of dust with planets. We used the COBE DIRBE Sky and Zodi Atlas and the IRAS Sky Survey Atlas to search for dynamical signatures of three different planets in the solar system dust complex: (1) We searched the COBE DIRBE Sky and Zodi Atlas for a wake of dust trailing Mars. We compare the DIRBE images to a model Mars wake based on the empirical model of the Earth's wake as seen by the DIRBE. (2) We searched the COBE DIRRE Sky and Zodi Atlas for Tiojan dust near

  4. 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

  5. Global potential of dust devil occurrence

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Mineral dust is a key constituent in the climate system. Airborne mineral dust forms the largest component of the global aerosol budget by mass and subsequently affects climate, weather and biogeochemical processes. There remains large uncertainty in the quantitative estimates of the dust cycle. Dry boundary-layer convection serves as an effective mechanism for dust uplift, typically through a combination of rotating dust devils and non-rotating larger and longer-lived convective plumes. These microscale dry-convective processes occur over length scales of several hundred metres or less. They are difficult to observe and model, and therefore their contribution to the global dust budget is highly uncertain. Using an analytical approach to extrapolate limited observations, Koch and Renno (2006) suggest that dust devils and plumes could contribute as much as 35%. Here, we use a new method for quantifying the potential of dust devil occurrence to provide an alternative perspective on this estimate. Observations have shown that dust devil and convective plume occurrence is favoured in hot arid regions under relatively weak background winds, large ground-to-air temperature gradients and deep dry convection. By applying such known constraints to operational analyses from the European Centre for Medium Range Weather Forecasts (ECMWF), we provide, to the best of the authors' knowledge, the first hourly estimates of dust devil occurrence including an analysis of sensitivity to chosen threshold uplift. The results show the expected diurnal variation and allow an examination of the seasonal cycle and day-to-day variations in the conditions required for dust devil formation. They confirm that desert regions are expected to have by far the highest frequency of dry convective vortices, with winds capable of dust uplift. This approach is used to test the findings of Koch and Renno (2006). Koch J., Renno N. (2006). The role of convective plumes and vortices on the global aerosol

  6. China Dust

    Atmospheric Science Data Center

    2013-04-16

    ... induced by surface topography, which can disturb the wind flow. A few small cumulus clouds are also visible, and are casting shadows ... Experiment, an international campaign aimed at studying the offshore transport of airborne particles from the Asian continent. For more ...

  7. Clear-Sky Closure Studies of Lower Tropospheric Aerosol and Water Vapor During ACE-2 Using Airborne Sunphotometer, Airborne In-Situ, Space-Borne, and Ground-Based Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Livingston, John M.; Russell, Philip B.; Durkee, Philip A.; Jonsson, Haflidi H.; Collins, Donald R.; Flagan, Richard C.; Seinfeld, John H.; Gasso, Santiago; Hegg, Dean A.; Oestroem, Elisabeth; Voss, Kenneth J.; Gordon, Howard R.; Formenti, Paolo; Andreae, Meinrat O.

    2000-01-01

    We report on clear-sky column closure experiments (CLEARCOLUMN) performed in the Canary Islands during the second Aerosol Characterization Experiment (ACE-2) in June/July 1997. We present CLEARCOLUMN results obtained by combining airborne sunphotometer and in-situ (optical particle counter, nephelometer, and absorption photometer) measurements taken aboard the Pelican aircraft, space-borne NOAA/AVHRR data and ground-based lidar and sunphotometer measurements. During both days discussed here, vertical profiles flown in cloud-free air masses revealed 3 distinctly different layers: a marine boundary layer (MBL) with varying pollution levels, an elevated dust layer, and a very clean layer between the MBL and the dust layer. A key result of this study is the achievement of closure between extinction or layer aerosol optical depth (AOD) computed from continuous in-situ aerosol size-distributions and composition and those measured with the airborne sunphotometer. In the dust, the agreement in layer AOD (lambda = 380-1060 nm) is 3-8%. In the MBL there is a tendency for the in-situ results to be slightly lower than the sunphotometer measurements (10-17% at lambda = 525 nm), but these differences are within the combined error bars of the measurements and computations.

  8. Comparing the Accuracy of Aboveground Biomass Estimates and Forest Structure Metrics at Large Footprint Level: Satellite Waveform Lidar vs. Discrete-Return Airborne Lidar

    NASA Astrophysics Data System (ADS)

    Popescu, S. C.; Zhao, K.; Gatziolis, D.

    2009-12-01

    The overall goal of this paper was to compare biomass estimates and forest structure metrics obtained by processing ICESat waveform data and spatially coincident discrete-return airborne lidar data over varied terrain conditions. For mostly flat-terrain conditions, we investigated lidar data over forests in east Texas, which are characteristics for most of the south-eastern United States, thus allowing terrain to be largely excluded as a source of error. For sloped-terrain, we used lidar data over forests in Oregon. With biomass estimates derived from waveform height metrics, we also compared ground elevation measurements and canopy parameters. Specific objectives were to: compare ground elevations and canopy height parameters derived from ICESat and airborne lidar; (2) investigate above ground biomass estimates; (3) develop a 3D ray-tracing model to simulate lidar waveforms over forests with sloped terrain; and (4) test model performance with real lidar data over terrain with varied topography. Over flat terrain, results indicated a very strong correlation for terrain elevations between ICESat and airborne lidar, with R-square values of 0.98 and sub-meter RMSE. ICESat height variables were able to explain 80% of the variance associated with the reference biomass derived from airborne lidar, with an RMSE of 37.7 Mg/ha. Most of the models for height metrics had R-square values above 0.9. Results from ongoing investigations for sloped-terrain are expected to establish practical procedures for improving analysis of waveform data in vegetation studies.

  9. Endosulfan transport: I. Integrative assessment of airborne and waterborne pathways.

    PubMed

    Raupach, M R; Briggs, P R; Ford, P W; Leys, J F; Muschal, M; Cooper, B; Edge, V E

    2001-01-01

    To reduce endosulfan (C9H6O3Cl6S; 6,7,8,9,10,10-hexachloro-1,5, 5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3-oxide) contamination in rivers and waterways, it is important to know the relative significances of airborne transport pathways (including spray drift, vapor transport, and dust transport) and waterborne transport pathways (including overland and stream runoff). This work uses an integrated modeling approach to assess the absolute and relative contributions of these pathways to riverine endosulfan concentrations. The modeling framework involves two parts: a set of simple models for each transport pathway, and a model for the physical and chemical processes acting on endosulfan in river water. An averaging process is used to calculate the effects of transport pathways at the regional scale. The results show that spray drift, vapor transport, and runoff are all significant pathways. Dust transport is found to be insignificant. Spray drift and vapor transport both contribute low-level but nearly continuous inputs to the riverine endosulfan load during spraying season in a large cotton (Gossypium hirsutum L.)-growing area, whereas runoff provides occasional but higher inputs. These findings are supported by broad agreement between model predictions and observed typical riverine endosulfan concentrations in two rivers. PMID:11401261

  10. [Occupational dust exposure and prevalence of respiratory symptoms among conduit repair workers].

    PubMed

    Kumagai, S; Kurumatani, N; Nakachi, S; Nakagiri, S; Hara, K

    1993-11-01

    The amount of water supply in Japan was 16 billion ton as of 1989. Water from rivers and other sources is purified, sterilized and then supplied to the residents through conduits. When conduits are accidentally damaged, they must be repaired by the workers of the Waterworks Bureau of the local government. In this task, the workers are exposed to airborne dust which develops while digging and filling the ground and cutting the conduit and the concrete covering the road. The purpose of the present study was to estimate the airborne dust exposure level among the workers and to investigate its effect on their respiratory organs. First, we measured the total dust exposure concentration of 20 conduit repair workers and the total dust concentration in 10 office rooms. Second, we conducted a self-administered questionnaire survey to estimate the prevalence of respiratory symptoms among the employees of 119 Waterworks Bureaus. The subjects of the analysis were 322 conduit repair workers and as their controls 345 clerical/engineering workers. The results can be summarized as follows: 1) The average daily total dust exposure while repairing conduits ranged from 0.27 to 5.05 mg/m3 (mean = 0.91 mg/m3), while that while exchanging water meters from 0.23 to 0.52 mg/m3 (mean 0.41 mg/m3). These values were 4.6 and 2.1 fold higher than the total dust concentration in office rooms (mean = 0.20 mg/m3). 2) With the use of fluorescent X-ray method, iron and aluminum were detected in all samples collected while repairing conduits and the intensity of X-ray increased with increase in weight of collected dust. Iron exposure concentration ranged from 0.006 to 0.095 mg/m3, which is much higher than the levels in the air in urban areas. Iron and aluminum could not be detected by fluorescent X-ray method in most of the samples collected in office rooms. These findings indicate that the main element in the dust collected while repairing conduits is soil, while that in office rooms is tobacco

  11. On the Role of Flash Floods for Dust Emission over North Africa: Alluvial Sediments acting as Dust Source

    NASA Astrophysics Data System (ADS)

    Schepanski, K.; Klueser, L.; Tegen, I.

    2014-12-01

    Studies analyzing satellite dust products show that numerous dust sources are located in the foothills of arid and semi-arid mountain regions. There, alluvial sediments deposited on valley bottoms and flood plains are very susceptible to wind erosion and frequently serve as dust source. This study focuses on the spatio-temporal distribution of dust source activation events over the mountain foothills and flood plains over North Africa. Satellite dust retrievals with sub-daily resolution such as from Meteosat Second Generation (MSG) Spinning Enhanced Visible and InfraRed Imager (SEVIRI) and METOP A/B Infrared Atmospheric Sounding Interferometer (IASI) instruments are used to identify dust source regions. Identified dust source regions are then linked to soil properties and land type classification data sets. Information on the mineralogical composition of transported dust inferred from IASI observation are used (a) to investigate the impact of different source geomorphologies and thus different radiative properties of airborne dust particles, and (b) to estimate the contribution of dust uplift from alluvial sediments compared to dust emission from non-hydrological sources. Ultimately, this study contributes to the understanding of controlling mechanism on the interannual variability of dust source activation and will improve current dust emission modules coupled to atmosphere models.

  12. 2-DUST: Dust radiative transfer code

    NASA Astrophysics Data System (ADS)

    Ueta, Toshiya; Meixner, Margaret

    2016-04-01

    2-DUST is a general-purpose dust radiative transfer code for an axisymmetric system that reveals the global energetics of dust grains in the shell and the 2-D projected morphologies of the shell that are strongly dependent on the mixed effects of the axisymmetric dust distribution and inclination angle. It can be used to model a variety of axisymmetric astronomical dust systems.

  13. Dust Emission Induced By Friction Modifications At Tool Chip Interface In Dry Machining In MMC{sub p}

    SciTech Connect

    Kremer, Arnaud; El Mansori, Mohamed

    2011-01-17

    This paper investigates the relationship between dust emission and tribological conditions at the tool-chip interface when machining Metal Matrix composite reinforced with particles (MMCp) in dry mode. Machining generates aerosols that can easily be inhaled by workers. Aerosols may be composed of oil mist, tool material or alloying elements of workpiece material. Bar turning tests were conducted on a 2009 aluminum alloy reinforced with different level of Silicon Carbide particles (15, 25 and 35% of SiCp). Variety of PCD tools and nanostructured diamond coatings were used to analyze their performances on air pollution. A spectrometer was used to detect airborne aerosol particles in the size range between 0.3{mu}m to 20 {mu}m and to sort them in 15 size channels in real time. It was used to compare the effects of test parameters on dust emission. Observations of tool face and chip morphology reveal the importance of friction phenomena. It was demonstrated that level of friction modifies chip curvature and dust emission. The increase of level of reinforcement increase the chip segmentation and decrease the contact length and friction area. A ''running in'' phenomenon with important dust emission appeared with PCD tool due to the tool rake face flatness. In addition dust generation is more sensitive to edge integrity than power consumption.

  14. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    Bressel, C.; Itzkan, I.; Nunes, J. E.; Hoge, F.

    1977-01-01

    The characteristics of an Airborne Oceanographic Lidar (AOL) are given. The AOL system is described and its potential for various measurement applications including bathymetry and fluorosensing is discussed.

  15. Measured and modelled concentrations and vertical profiles of airborne particulate matter within the boundary layer of a street canyon.

    PubMed

    Colls, J J; Micallef, A

    1999-09-01

    Concentrations and vertical profiles of various fractions of airborne particulate matter (suspended particulate matter (SPM), PM10 and PM2.5) have been measured over the first three metres from ground in a street canyon. Measurements were carried out using automated near real-time apparatus called the Kinetic Sequential Sampling (KSS) system. KSS system is essentially an electronically-controlled lift carrying a real-time particle monitor for sampling air sequentially, at different heights within the breathing zone, which includes all heights within the surface layer of a street canyon at which people may breathe. Data is automatically logged at the different receptor levels, for the determination of the average vertical concentration profile of airborne particulate matter. For measuring the airborne particle concentration, a Grimm Dust Monitor 1.104/5 was used. The recorded data also allows for time series analysis of airborne particulate matter concentration at different heights. Time series data and hourly-average vertical concentration profiles in the boundary layer of the confines of a street are thought to be mainly determined by traffic emissions and traffic associated processes. Hence the measured data were compared with results of a street canyon emission-dispersion model in time and space. This Street Level Air Quality (SLAQ) model employs the plume-box technique and includes modules for simulating vehicle-generated effects such as thermally- and mechanically-generated turbulence and resuspension of road dust. Environmental processes, such as turbulence resulting from surface sensible heat and the formation of sulphate aerosol from sulphur dioxide exhaust emissions, are taken into account. The paper presents an outline description of the measuring technique and model used, and a comparison of the measured and modelled data. PMID:10535122

  16. Electrostatic Dust Detector with Improved Sensitivity

    SciTech Connect

    D.P. Boyle, C.H. Skinner, and A. L. Roquemore

    2008-06-09

    Methods to measure the inventory of dust particles and to remove dust if it approaches safety limits will be required in next-step tokamaks such as ITER. An electrostatic dust detector, based on a fine grid of interlocking circuit traces, biased to 30 or 50 V, has been developed for the detection of dust on remote surfaces in air and vacuum environments. Gaining operational experience of dust detection on surfaces in tokamaks is important, however the level of dust generated in contemporary short-pulse tokamaks is comparatively low and high sensitivity is necessary to measure dust on a shot-by-shot basis. We report on modifications in the detection electronics that have increased the sensitivity of the electrostatic dust detector by a factor of up to 120, - a level suitable for measurements on contemporary tokamaks.

  17. An update on airborne contact dermatitis: 2001-2006.

    PubMed

    Santos, Raquel; Goossens, An

    2007-12-01

    Reports on airborne dermatoses are mainly published in the context of occupational settings. Hence, in recent years, dermatologists and also occupational physicians have become increasingly aware of the airborne source of contact dermatitis, resulting mainly from exposure to irritants or allergens. However, their occurrence is still underestimated, because reports often omit the term 'airborne' in relation to dust or volatile allergens. For the present update, we screened the journals 'Contact Dermatitis' (July 2000 to December 2006); 'Dermatitis', formerly named 'American Journal of Contact Dermatitis'; 'La Lettre du Gerda' (January 2000 to December 2006); and also included relevant articles from other journals published during the same period. This resulted in an updated list of airborne dermatitis causes. PMID:17988283

  18. Effects of different levels of wheat bran, rice bran and maize powder supplementation with saw dust on the production of shiitake mushroom (Lentinus edodes (Berk.) Singer)

    PubMed Central

    Moonmoon, Mahbuba; Shelly, Nasrat Jahan; Khan, Md. Asaduzzaman; Uddin, Md. Nazim; Hossain, Kamal; Tania, Mousumi; Ahmed, Saleh

    2010-01-01

    The cultivation of shiitake mushroom (Lentinus edodes) is increasing rapidly in Bangladesh due to its nutritional and medicinal importance with excellent flavor and longer shelf life. With the aim of increased production, we have cultivated L. edodes on saw dust (SD) supplemented with different levels (10%, 15%, 20%, 25%, 30%, 35% and 40%) of wheat bran (WB), rice bran (RB), maize powder (MP) and their combination (WB+RB+MP = 1:1:1) to investigate the growth, yield and quality of this mushroom. Most of the growth, yield and quality parameters varied significantly when mushrooms were cultivated with different levels of supplementation. The yield of mushroom was increased with the level of each supplementation upto a certain level, and then decreased. SD supplemented with 25% WB produced the highest number of fruiting bodies (34.8/500 g packet), highest biological yield (153.3/500 g packet), and biological efficiency (76.6%) of L. edodes. But the yield of the best quality mushroom was observed on SD with 40% WB supplementation; however, the qualities were not always supplementation dose dependent. In this study, we report that 25% WB supplementation with SD may be very effective for higher yield and 40% WB supplementation for better quality of L. edodes. PMID:23961143

  19. Allergies, asthma, and dust

    MedlinePlus

    Allergic rhinitis - dust ... make allergies or asthma worse are called triggers. Dust is a common trigger. When your asthma or allergies become worse due to dust, you are said to have a dust allergy. ...

  20. Dust control for draglines

    SciTech Connect

    Grad, P.

    2009-09-15

    Monitoring dust levels inside draglines reveals room for improvement in how filtration systems are used and maintained. The Australian firm BMT conducted a field test program to measure airflow parameters, dust fallout rates and dust concentrations, inside and outside the machine house, on four draglines and one shovel. The study involved computational fluid dynamics (CFD) simulations. The article describes how the tests were made and gives results. It was not possible to say which of the two main filtration systems currently used on Australian draglines - Dynavane or Floseps - performs better. It would appear that more frequent maintenance and cleaning would increase the overall filtration performance and systems could be susceptible to repeat clogging in a short time. 2 figs., 1 photos.

  1. Some Pharmacological Actions of Cotton Dust and Other Vegetable Dusts

    PubMed Central

    Nicholls, P. J.

    1962-01-01

    Aqueous extracts of cotton and other vegetable dusts cause contraction of the isolated ileum and tracheal muscle of the guinea-pig, and of isolated human bronchial muscle. The levels of this contractor activity place the dusts of cotton, flax, and jute in the order of the probable incidence of byssinosis occurring in the mills spinning these fibres. Extracts of cotton dust possess a histamine-liberating activity and contain a permeability-increasing component. These actions are of plant origin and are found in the pericarp and bracts of the cotton boll. Histamine and 5-hydroxytryptamine have also been found in some cotton dust samples. The formation of histamine by bacterial action in cotton dust does not take place under conditions found in cotton mills. The smooth muscle contractor substance is organic in nature, relatively heat-stable, and dialysable. The relevance of these results to the symptoms of byssinosis is discussed. PMID:14479451

  2. Saharan Dust Export towards the Caribbean: Dust Sources and Atmospheric Circulation over North Africa

    NASA Astrophysics Data System (ADS)

    Schepanski, Kerstin; Heinold, Bernd; Groß, Silke; Schäfler, Andreas; Weinzierl, Bernadett; Sauer, Daniel; Walser, Adrian; Tegen, Ina

    2015-04-01

    Studies analysing satellite observations illustrate the spatial and temporal distribution of emitting dust sources. Results show that high surface wind speeds related to the break-down of the nocturnal low-level jet (LLJ) occurring during the morning hours are frequent driving mechanism for dust uplift in the Sahara desert. Here, we present a study investigating atmospheric circulation pattern over North Africa favouring (a) dust entrainment into the boundary layer and (b) dust export towards the Caribbean Sea. Satellite-based information on the spatio-temporal distribution of dust source activation (DSA) events inferred from 15-minute Meteosat Second Generation (MSG) Spinning Enhanced Visible and InfraRed Imager (SEVIRI) dust observations are linked to atmospheric circulation regimes over North Africa. By means of air-mass trajectories, which map the dust export from North Africa toward the SALTRACE ground observation site at Barbados, cases are selected which link DSA regions with dust events observed at Barbados. These cases are then examined with regard to the atmospheric conditions during dust emission and geomorphologic dust source characteristic. Dust properties inferred from LIDAR observation using the POLIS system and measurements taken during Falcon research flights are compared to the different dust source locations and atmospheric conditions during dust emission. Altogether, the results from this study aim at illustrating the relevance of knowing the dust source locations in concert with the atmospheric circulation. Ultimately, this study addresses the question of what is finally transported across the Atlantic towards the Caribbean from which dust source region.

  3. Southeastward Dust Transport during the 16-24 March 2006 Asian Dust Event

    NASA Astrophysics Data System (ADS)

    Tsai, F.; Liu, T.; Hsu, S.; Chen, W.; Tu, J.

    2012-04-01

    Synoptic analyses and regional dust models are applied to analyze the dust measurements obtained during the Asian dust events from 16 to 24 March, 2006, in order to understand the controlling mechanism leading to the dust transport far southeastward of the continent. The southeastward transported dust concentrations measured over Taiwan are traced back to their source areas. By tracing the dust loaded air parcels, the synoptic characteristics of the dust event during generation, transport, and dissipation are inspected and compared with an eastward transported event. It has been found that the synoptic mechanism, rather than the emission intensity, leads to the high dust concentration far southeastward off the continent. Most southeastward moving dust clouds are generated behind the surface front in the descent regions and then transported behind a deep lower-level trough, in which the prevailing northerlies or northwesterlies lead to the southeastward dust transported into the tropics. Without a deep lower-level trough, the dust clouds tend to be transported eastward. Surface lidar observations also show descent of the dust concentrations during their southeastward transport. After moving offshore, the anticyclonic circulation in the leading edge of the surface high circulates the dust parcels ahead of the high-pressure center in a southwestward direction towards the seashore off the Southeast China. With the deceleration of the wind speed, the dust clouds then slowly dissipate over the tropics of the Western Pacific, thus providing nutrients to the marine phytoplanktons.

  4. IL-33 and thymic stromal lymphopoietin mediate immune pathology in response to chronic airborne allergen exposure.

    PubMed

    Iijima, Koji; Kobayashi, Takao; Hara, Kenichiro; Kephart, Gail M; Ziegler, Steven F; McKenzie, Andrew N; Kita, Hirohito

    2014-08-15

    Humans are frequently exposed to various airborne allergens in the atmospheric environment. These allergens may trigger a complex network of immune responses in the airways, resulting in asthma and other chronic airway diseases. In this study, we investigated the immunological mechanisms involved in the pathological changes induced by chronic exposure to multiple airborne allergens. Naive mice were exposed intranasally to a combination of common airborne allergens, including the house dust mite, Alternaria, and Aspergillus, for up to 8 wk. These allergens acted synergistically and induced robust eosinophilic airway inflammation, specific IgE Ab production, type 2 cytokine response, and airway hyperresponsiveness in 4 wk, followed by airway remodeling in 8 wk. Increased lung infiltration of T cells, B cells, and type 2 innate lymphoid cells was observed. CD4(+) T cells and type 2 innate lymphoid cells contributed to the sources of IL-5 and IL-13, suggesting involvement of both innate and adaptive immunity in this model. The lung levels of IL-33 increased quickly within several hours after allergen exposure and continued to rise throughout the chronic phase of inflammation. Mice deficient in IL-33R (Il1rl1(-/-)) and thymic stromal lymphopoietin receptor (Tslpr(-/-)) showed significant reduction in airway inflammation, IgE Ab levels, and airway hyperresponsiveness. In contrast, mice deficient in IL-25R or IL-1R showed minimal differences as compared with wild-type animals. Thus, chronic exposure to natural airborne allergens triggers a network of innate and adaptive type 2 immune responses and airway pathology, and IL-33 and thymic stromal lymphopoietin most likely play key roles in this process. PMID:25015831

  5. Efficiency of dust sampling inlets in calm air.

    PubMed

    Breslin, J A; Stein, R L

    1975-08-01

    Measurement of airborne dust concentrations usually involves drawing a sample of the dust-laden air into the measuring instrument through an inlet. Even if the surrounding air is calm, theoretical calculations predict that large particles may not be sampled accurately due to the combined effects of gravity and inertia on the particles near the sampling inlet. Tests were conducted to determine the conditions of particle size, inlet radius, and flow rare necessary for accurate dust sampling. A coal-dust aerosol was sampled simultaneously through inlets of different diameters at the same volume flow-rate and collected on filters. The dust was removed from the filters and the particles were counted and sized with a Coulter counter. Results showed that published criteria for inlet conditions for correct sampling are overly restrictive and that respirable-size particles are sampled correctly in the normal range or operation of most dust sampling instruments. PMID:1227283

  6. Direct-reading inhalable dust monitoring--an assessment of current measurement methods.

    PubMed

    Thorpe, Andrew; Walsh, Peter T

    2013-08-01

    Direct-reading dust monitors designed specifically to measure the inhalable fraction of airborne dust are not widely available. Current practice therefore often involves comparing the response of photometer-type dust monitors with the concentration measured with a reference gravimetric inhalable sampler, which is used to adjust the dust monitor measurement. However, changes in airborne particle size can result in significant errors in the estimation of inhalable concentration by this method. The main aim of this study was to assess how these dust monitors behave when challenged with airborne dust containing particles in the inhalable size range and also to investigate alternative dust monitors whose response might not be as prone to variations in particle size or that could be adapted to measure inhalable dust concentration. Several photometer-type dust monitors and a Respicon TM, tapered element oscillating microbalance (TEOM) personal dust monitor (PDM) 3600, TEOM 1400, and Dustrak DRX were assessed for the measurement of airborne inhalable dust during laboratory and field trials. The PDM was modified to allow it to sample and measure larger particles in the inhalable size range. During the laboratory tests, the dust monitors and reference gravimetric samplers were challenged inside a large dust tunnel with aerosols of industrial dusts known to present an inhalable hazard and aluminium oxide powders with a range of discrete particle sizes. A constant concentration of each dust type was generated and peak concentrations of larger particles were periodically introduced to investigate the effects of sudden changes in particle size on monitor calibration. The PDM, Respicon, and DataRam photometer were also assessed during field trials at a bakery, joinery, and a grain mill. Laboratory results showed that the Respicon, modified PDM, and TEOM 1400 observed good linearity for all types of dust when compared with measurements made with a reference IOM sampler; the

  7. Rocket dust storms and detached layers in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Spiga, A.; Faure, J.; Madeleine, J.; Maattanen, A. E.; Forget, F.

    2012-12-01

    Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling with radiatively-active transported dust to predict the evolution of a local dust storm monitored by OMEGA onboard Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, in lieu of latent heating in moist convection on Earth. We propose to use the terminology "rocket dust storm", or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30 to 50 km). Combined to horizontal transport by large-scale winds, rocket dust storms form detached layers of dust reminiscent of those observed with instruments onboard Mars Global Surveyor and Mars Reconnaissance Orbiter. Detached layers are stable over several days owing to nighttime sedimentation being unable to counteract daytime convective transport, and to the resupply of convective energy at sunrise. The peak activity of rocket dust storms is expected in low-latitude regions at clear season, which accounts for the high-altitude tropical dust maximum unveiled by Mars Climate Sounder. Our findings on dust-driven deep convection have strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.ensity-scaled dust optical depth at local times 1400 1600 and 1800 (lat 2.5°S, Ls 135°) hortwave heating rate at local time 1500 and latitude 2.5°S.

  8. Existence state of bromine as an indicator of the source of brominated flame retardants in indoor dust.

    PubMed

    Suzuki, Go; Kida, Akiko; Sakai, Shin-ichi; Takigami, Hidetaka

    2009-03-01

    Indoor dust is an important medium for human exposure to brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs). In this study, we used micro X-ray fluorescence spectrometry (XRFS), digital optical microscopy, and gas chromatography-high resolution mass spectrometry to investigate the existence state of bromine as an indicator of the source of BFRs in indoor dusts and in dusts from the interior of televisions collected in Japan. By means of micro XRFS bromine mapping conducted at a 0.5-s dwell time, we were able to detect bromine levels as low as about 0.1% at each point of about a beam diameter of 50 microm across. The presence of fragments containing 1.0% or more bromine was confirmed in 27 of the 48 dust samples tested. Using magnified images of the fragments, we classified them roughly into particulates and fibrous substances. We analyzed PBDEs in the fragments containing high concentrations of bromine (> or = 0.1%) and confirmed that the fragments contained PBDEs, mainly BDE 209. Furthermore, to detect bromine concentrations < or = 0.1% in the dust samples, we analyzed the samples at a dwell time of 100 s to enhance the detection sensitivity of mapping; atthis dwell time, we confirmed the presence of bromine in the dust coating. Our results suggest that bromine is transferred from products to dust matrixes not only through miniaturization and subsequent direct migration into dust as plastic and textile fragments but also through other pathways such as vaporization and airborne transfer of microparticulates. PMID:19350916

  9. The impact of drinking water, indoor dust and paint on blood lead levels of children aged 1–5 years in Montréal (Québec, Canada)

    PubMed Central

    Levallois, Patrick; St-Laurent, Julie; Gauvin, Denis; Courteau, Marilène; Prévost, Michèle; Campagna, Céline; Lemieux, France; Nour, Shokoufeh; D'Amour, Monique; Rasmussen, Pat E

    2014-01-01

    Lead is neurotoxic at very low dose and there is a need to better characterize the impact of domestic sources of lead on the biological exposure of young children. A cross-sectional survey evaluated the contribution of drinking water, house dust and paint to blood lead levels (BLLs) of young children living in old boroughs of Montréal (Canada). Three hundred and six children aged 1 to 5 years and currently drinking tap water participated in the study. For each participant, residential lead was measured in kitchen tap water, floor dust, windowsill dust and house paint and a venous blood sample was analyzed. Multivariate logistic regression was used to evaluate the association between elevated BLL in the children (≥ 75th percentile) and indoor lead contamination by means of odds ratios (OR) using 95% confidence intervals (CI). There was an association between BLL ≥75th percentile (1.78 μg/dL) and water lead when the mean water concentration was >3.3 μg/L: adjusted OR=4.7 (95% CI: 2.1–10.2). Windowsill dust loading >14.1 μg/ft2 was also associated with BLL ≥1.78 μg/dL: adjusted OR=3.2 (95% CI: 1.3–7.8). Despite relatively low BLLs, tap water and house dust lead contribute to an increase of BLLs in exposed young children. PMID:23361441

  10. Characterization of airborne individual particles collected in an urban area, a satellite city and a clean air area in Beijing, 2001

    NASA Astrophysics Data System (ADS)

    Shi, Zongbo; Shao, Longyi; Jones, T. P.; Whittaker, A. G.; Lu, Senlin; Bérubé, K. A.; He, Taoe; Richards, R. J.

    Collection campaigns for PM 10 and PM 2.5 have been conducted in a northwestern Beijing urban area in monthly periods over 2001, with 7 days collection per month. The samples were also collected simultaneously in a satellite city, Nankou, and a clean air area near the Ming Tombs Reservoir (MTR) over the domestic heating (March) and non-heating (July/August) periods in 2001 (both for one week). To assist the analysis, three types of 'source' particulate matter (PM) samples were taken. These consisted of coal combustion ash collected on top of a coke oven; dust storm particles collected during dust storm periods; and roadside PM 10 collected on a major road in Beijing. Monitoring results reveal that, in the urban area, particle mass levels were higher in winter than in other seasons. The 1-week/month average PM 10 mass levels were over 250 μg m -3 in winter. The particle mass levels in the satellite city were slightly lower than those at the urban site, and the lowest mass levels occurred at the MTR site. The morphology and chemical composition of individual airborne particles were determined by scanning electron microscopy, and image analysis was employed to study the number-size distributions. The number-size distributions of mineral particles showed that those in the Asia-Dust storm (ADS) collections are mostly coarser than 1 μm, while mineral particles of the non-ADS collections are predominately finer than 1 μm. The particles in the respirable (<2.5 μm) fraction accounted for 99% of the total particles in airborne PM samples. Soot aggregates were generally the most abundant components in airborne PM samples at all three sites. The fly ash (spherical) particles at the MTR site were significantly enriched over the heating period, indicating a domestic coal-burning source.

  11. A DUST-SETTLING CHAMBER FOR SAMPLING-INSTRUMENT COMPARISON STUDIES

    EPA Science Inventory

    Introduction: Few methods exist that can evenly and reproducibly deposit dusts onto surfaces for surface-sampling methodological studies. A dust-deposition chamber was designed for that purpose.

    Methods: A 1-m3 Rochester-type chamber was modified to produce high airborne d...

  12. 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

  13. 42 CFR 84.1152 - Silica dust loading test; respirators designed as protection against dusts, fumes, and mists...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having an air contamination level less than 0.05 milligram per... Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having...

  14. 42 CFR 84.1152 - Silica dust loading test; respirators designed as protection against dusts, fumes, and mists...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having an air contamination level less than 0.05 milligram per... Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having...

  15. Airborne gravity is here

    SciTech Connect

    Hammer, S.

    1982-01-11

    After 20 years of development efforts, the airborne gravity survey has finally become a practical exploration method. Besides gravity data, the airborne survey can also collect simultaneous, continuous records of high-precision magneticfield data as well as terrain clearance; these provide a topographic contour map useful in calculating terrain conditions and in subsequent planning and engineering. Compared with a seismic survey, the airborne gravity method can cover the same area much more quickly and cheaply; a seismograph could then detail the interesting spots.

  16. Salmonella mutagenicity assessment of airborne particulate matter collected from urban areas of Rio Grande do Sul State, Brazil, differing in anthropogenic influences and polycyclic aromatic hydrocarbon levels.

    PubMed

    Pereira, Tatiana S; Gotor, Gemma N; Beltrami, Laiana S; Nolla, Celia G; Rocha, Jocelita A V; Broto, Francesc P; Comellas, Lluis R; Vargas, Vera M F

    2010-09-30

    Urban areas are both major sources and major targets of air pollution. The atmospheric environment receives diverse chemical substances, including genotoxic agents that may affect human health. The purpose of this study was to evaluate and compare the atmospheric quality in two urban areas in Rio Grande do Sul State (Brazil), under the influence of greater (Site 1) or lesser (Site 2) anthropogenic sources. Polycyclic aromatic hydrocarbons (PAHs) of environmental interest were quantified and the Salmonella/microsome assay was used for the measurement of mutagenicity. Organic compounds extracted from the airborne particulate matter were analyzed by high-performance liquid chromatography (HPLC) to detect PAHs of interest (known or possible carcinogens). The organic extracts were also tested for mutagenic and cytotoxic activity in the Salmonella/microsome assay with strains TA98, TA100, YG1021 and YG1024, with or without S9 activation. At Site 1, benzo[ghi]perylene (BghiP) and indeno[1,2,3-cd]pyrene (IP) were found at higher concentrations and mutagenicity (revertants per μg extract) varied from 1.0±0.25 (TA98, no S9) to 5.2±0.45 (TA98, S9). At Site 2, BghiP and IP were present in larger amounts and the mutagenic responses ranged from 0.6 to 3.7 revertants per μg (both in TA98, S9). The occurrence of BghiP and IP may be related to vehicular emissions. These and the other PAHs studied, as well as the nitro compounds, may contribute to the mutagenicity found in these airborne particles. PMID:20643224

  17. Radiative Energetics of Mineral Dust Aerosols from Ground-Based Measurements

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee; Hansell, Richard A.

    2011-01-01

    Airborne dust aerosols worldwide contribute a significant part to air quality problems and, to some extent, regional climatic issues (e.g., radiative forcing, hydrological cycle, and primary biological productivity in oceans). Evaluating the direct solar radiative effect of dust aerosols is relatively straightforward due in part to the relatively large SIN ratio in broadband irradiance measurements. The longwave (LW) impact, on the other hand, is rather difficult to ascertain since the measured dust signal level (approx.10 W/sq m) is on the same order as the instrumental uncertainties. Although the magnitude of the LW impact is much smaller than that of the shortwave (SW), it can still have a noticeable influence on the energy distribution of Earth-atmosphere system, particularly due to the strong light-absorptive properties commonly found in many terrestrial minerals. The current effort is part of an ongoing research study to perform a global assessment of dust direct aerosol radiative effects (DARE) during major field deployments of key dust source regions worldwide. In this work we present results stemming from two previous field deployments: the 2006 NASA African Monsoon Multidisciplinary Activities and the 2008 Asian Monsoon Years, both utilizing NASA Goddard's mobile ground-based facility. The former study focused on transported Saharan dust at Sal (16.73degN, 22.93degW), Cape Verde along the west coast of Africa while the latter focused on Asian dust at Zhangye (39.082degN, 100.276degE), China near the source between the Taklimakan and Gobi deserts. Due to the compelling variability in spatial and temporal scale of dust properties during field experiments, a deterministic I-D radiative transfer model constrained by local measurements (i.e., spectral photometry/interferometry and lidar for physical/microphysical, mineralogy, and single-scattering properties) is employed to evaluate dust's local instantaneous SW/LW DARE both at the surface and at the top of

  18. Escaping the regulatory dust bowl: fugitive dust and the Clean Air Act

    SciTech Connect

    Probst, G.L.; Becker, R.E. Jr.

    1982-01-01

    The Environmental Protection Agency's (EPA's) regulatory program, as it relates to particulates, is overly complicated. In attempting to accommodate statutory language insensitive to particulate differences, after becoming aware of the varying effects of different-sized particles, EPA has developed an unworkable program. Although agricultural, recreational, transportation, and industrial activities contribute to the airborne dust (or, in the Clean Air Act vernacular, fugitive dust), this article focuses on mining activities. Surface mining inevitably stirs up considerable fugitive dust, and a description of mining activities in arid conditions, and how they fit in with a developing regulatory program, reveals a story of a national program that fails to provide for rational policy and regional flexibility. The article also recommends some regulatory and statutory solutions that could relatively easily correct EPA's fugitive dust program.

  19. The Dynamics and Characteristics of Aeolian Dust in Dryland Central Asia: Possible Impacts on Respiratory Health in the Aral Sea Basin

    NASA Astrophysics Data System (ADS)

    Wiggs, G. F.; O'Hara, S.; Wegerdt, J.; van der Meer, J.; Small, I.; Hubbard, R.

    2003-12-01

    evidence of a dose-related impact of dust levels on lung function. These associations were statistically significant for all measures of dust exposure but were most marked for levels of winter dust exposure and level of PM2.5 exposure. The results from this study suggest that aeolian dust dynamics in the region are spatially and temporally highly variable and, counter to local and regional perceptions, the former bed of the Aral Sea does not appear to be the only significant source. Nevertheless, there is also evidence of a dose-related impact of airborne dust on the risk of having abnormally low lung function in children living in the Aral Sea Area.

  20. Immune response to flour and dust mites in a United Kingdom bakery.

    PubMed Central

    Tee, R D; Gordon, D J; Gordon, S; Crook, B; Nunn, A J; Musk, A W; Venables, K M; Taylor, A J

    1992-01-01

    In a study of 279 United Kingdom bakery workers a high prevalence of immunological response to storage mites was found. To determine whether this was the consequence of exposure to storage mites in bakery work, a population of salt packing workers was examined as a comparison group not at occupational risk of exposure to storage mites. Forty two per cent of both groups were atopic (had a positive skin prick response greater than negative controls to D pteronyssinus, grass pollen, or cat fur by 2 mm or more) and 33% had an immediate skin prick test response to at least one of four storage mites (L destructor, G domesticus, T putrescentiae, A Siro). A higher percentage of the salt packing workers than the bakery workers had a positive radioallergosorbent test (RAST) (greater than or equal to 0.35 PRU) to D pteronyssinus and to the four storage mites. Logistic regression analysis identified atopy as the most significant variable for a positive skin test and RAST response to storage mites in both groups of workers. RAST inhibition was used to analyse extracted area and personal air samples. Analysis of static area samples for aeroallergen showed immunological identity with flour but L destructor was found in only one of seven exposed filters. The concentration of airborne flour was related to exposure rank of perceived dustiness and gravimetric measurement of total dust. Nineteen out of 32 filters from workers in jobs with higher dust exposure (rank >/=6) had a level of > 10 microgram/m(3) flour whereas this concentrations was exceeded in only one of 23 filters from workers in low dust exposure (< rank 6). It is concluded that storage mites are not of special significance in allergic responses in bakery workers. The development of immunological (and airway) responsiveness to inhaled flour dust is increased in those exposed to higher concentrations of airborne allergen, which appears to be predominantly flour and not storage mites. PMID:1515350

  1. Modeling the emission, transport and deposition of contaminated dust from a mine tailing site.

    PubMed

    Stovern, Michael; Betterton, Eric A; Sáez, A Eduardo; Villar, Omar Ignacio Felix; Rine, Kyle P; Russell, Mackenzie R; King, Matt

    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 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 significantly contaminated with lead and arsenic with an average soil concentration of 1616 and 1420 ppm, respectively. Similar levels of these contaminants have also been measured in soil samples taken from the area surrounding the mine tailings. Using a computational fluid dynamics model, we have been able to model dust transport from the mine tailings to the surrounding region. The model includes a distributed Eulerian model to simulate fine aerosol transport and a Lagrangian approach to model fate and transport of larger particles. 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. PMID:24552963

  2. A new data set of soil mineralogy for dust-cycle modeling

    NASA Astrophysics Data System (ADS)

    Journet, E.; Balkanski, Y.; Harrison, S. P.

    2013-09-01

    The mineralogy of airborne dust affects the impact of dust particles on direct and indirect radiative forcing, on atmospheric chemistry and on biogeochemical cycling. It is determined partly by the mineralogy of the dust-source regions and partly by size-dependent fractionation during erosion and transport. Here we present a data set that characterizes the clay and silt sized fractions of global soil units in terms of the abundance of 12 minerals that are important for dust-climate interactions: quartz, feldspars, illite, smectite, kaolinite, chlorite, vermiculite, mica, calcite, gypsum, hematite and goethite. The basic mineralogical information is derived from the literature, and is then expanded following explicit rules, in order to characterize as many soil units as possible. We present three alternative realisations of the mineralogical maps that account for the uncertainties in the mineralogical data. We examine the implications of the new database for calculations of the single scattering albedo of airborne dust and thus for dust radiative forcing.

  3. Dust Studies in DIII-D Tokamak

    SciTech Connect

    Rudakov, D L; West, W P; Groth, M; Yu, J H; Boedo, J A; Bray, B D; Brooks, N H; Fenstermacher, M E; Hollmann, E M; Hyatt, A W; Krasheninnikov, S I; Lasnier, C J; Moyer, R A; Pigarov, A Y; Smirnov, R; Solomon, W M; Wong, C C

    2008-04-15

    Studies of submicron dust using Mie scattering from Nd:YAG lasers and video data of micron to sub-millimeter sized dust on DIII-D tokamak have provided the first data of dust sources and transport during tokamak discharges. During normal operation on DIII-D dust observation rates are low, a few events per discharge or less. The net carbon content of the dust corresponds to a carbon atom density a few orders of magnitude below the core impurity density. Statistical analysis of Mie data collected over months of operation reveal correlation of increased dust rate with increased heating power and impulsive wall loading due to edge localized modes (ELMs) and disruptions. Generation of significant amounts of dust by disruptions is confirmed by the camera data. However, dust production by disruptions alone is insufficient to account for estimated in-vessel dust inventory in DIII-D. After an extended entry vent, thousands of dust particles are observed by cameras in the first 2-3 plasma discharges. Individual particles moving at velocities up to {approx}300 m/s, breakup of larger particles into pieces, and collisions of particles with walls are observed. After {approx}70 discharges, dust levels are reduced to a few events per discharge. In order to calibrate diagnostics and benchmark modeling, milligram amounts of micron-sized carbon dust have been injected into DIII-D discharges, leading to the core carbon density increase by a factor of 2-3. Following injection, dust trajectories in the divertor are mostly in the toroidal direction, consistent with the ion drag force. Dust from the injection is observed in the outboard midplane by a fast framing camera. The observed trajectories and velocities of the dust particles are in qualitative agreement with modeling by the 3D DustT code.

  4. Dust Studies in DIII-D Tokamak

    SciTech Connect

    Rudakov, D. L.; Yu, J. H.; Boedo, J. A.; Hollmann, E. M.; Krasheninnikov, S. I.; Moyer, R. A.; Pigarov, A. Yu.; Smirnov, R.; West, W. P.; Bray, B. D.; Brooks, N. H.; Hyatt, A. W.; Wong, C. P. C.; Groth, M.; Fenstermacher, M. E.; Lasnier, C. J.; Solomon, W. M.

    2008-09-07

    Studies of submicron dust using Mie scattering from Nd:YAG lasers and video data of micron to sub-millimeter sized dust on DIII-D tokamak have provided the first data of dust sources and transport during tokamak discharges. During normal operation on DIII-D dust observation rates are low, a few events per discharge or less. The net carbon content of the dust corresponds to a carbon atom density a few orders of magnitude below the core impurity density. Statistical analysis of Mie data collected over months of operation reveal correlation of increased dust rate with increased heating power and impulsive wall loading due to edge localized modes (ELMs) and disruptions. Generation of significant amounts of dust by disruptions is confirmed by the camera data. However, dust production by disruptions alone is insufficient to account for estimated in-vessel dust inventory in DIII-D. After an extended entry vent, thousands of dust particles are observed by cameras in the first 2-3 plasma discharges. Individual particles moving at velocities up to {approx}300 m/s, breakup of larger particles into pieces, and collisions of particles with walls are observed. After {approx}70 discharges, dust levels are reduced to a few events per discharge. In order to calibrate diagnostics and benchmark modeling, milligram amounts of micron-sized carbon dust have been injected into DIII-D discharges, leading to the core carbon density increase by a factor of 2-3. Following injection, dust trajectories in the divertor are mostly in the toroidal direction, consistent with the ion drag force. Dust from the injection is observed in the outboard midplane by a fast framing camera. The observed trajectories and velocities of the dust particles are in qualitative agreement with modeling by the 3D DustT code.

  5. Trends in implementation of longwall dust controls

    SciTech Connect

    Haney, R.A.

    1995-12-31

    During the last ten years, longwall mining systems have undergone many changes. Panel widths and lengths have increased. Long-wall faces have become more automated. Average production from individual longwall panels has increased from 1,000 to 3,600 tons per shift. To control the dust generation resulting from the higher production, longwall dust control systems have integrated various dust control techniques. Systems designed to control dust generated at the crusher/stageloader, shearer, and supports are common to most longwall faces. A survey was made of the dust controls that are currently in place on all the longwalls in the U.S. This survey addressed the types of controls used to reduce dust generated at the crusher/stageloader, shearer and roof support movement. Additionally, information on face ventilation rates, cutting cycle and level of automation was obtained. The purpose of this paper is to review the dust control practices that have been implemented throughout the United States and to identify those controls that are being used on high production longwall faces. Additionally, a model is used to demonstrate how ventilation and automation affect occupational exposure. Automation of roof support movement can offer some of the greatest reductions in occupational dust exposures. While technically feasible, its full benefit has not been fully realized by the industry. Until technology to fully automate longwall mining systems becomes more reliable, future dust control systems must rely on increased ventilation, application of headgate dust collectors, improved shearer dust controls and improved shield dust suppression systems.

  6. Raytheon low temperature RSP2 cryocooler airborne testing

    NASA Astrophysics Data System (ADS)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2014-01-01

    The Raytheon Cryocooler Product Line tested the Low Temperature Stirling / Pulse Tube Hybrid 2-Stage (LTRSP2) cryocooler for an airborne application during 2012. Several tests were carried out to verify the ability of the machine to operate in an airborne environment. The vacuum level and heat rejection surface temperatures were varied to determine the performance over the excursions. Vibration testing was performed to prove that the LT-RSP2 cryocooler can operate on an airborne platform. This paper will present the results of the airborne characterization testing.

  7. Raytheon low temperature RSP2 cryocooler airborne testing

    NASA Astrophysics Data System (ADS)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2013-09-01

    The Raytheon Cryocooler Product Line tested the Low Temperature Stirling / Pulse Tube Hybrid 2-Stage (LTRSP2) cryocooler for an airborne application during 2012. Several tests were carried out to verify the ability of the machine to operate in an airborne environment. The vacuum level and heat rejection surface temperatures were varied to determine the performance over the excursions. Vibration testing was performed to prove that the LT-RSP2 cryocooler can operate on an airborne platform. This paper will present the results of the airborne characterization testing.

  8. Chemical speciation of lead dust associated with primary lead smelting.

    PubMed Central

    Spear, T M; Svee, W; Vincent, J H; Stanisich, N

    1998-01-01

    The research presented in this article assessed geochemical factors relating to dust produced during primary lead smelting. Bulk dust samples and size-selective airborne dust samples were collected from four areas of a primary lead smelter and analyzed by X-ray diffraction and sequential chemical extraction. X-ray diffraction showed that the smelter dusts were composed primarily of sulfides, oxides, sulfates, and silicates of metal ores, with galena being the primary dust component. Sequential extraction revealed the solubility of lead compounds at less than 7% in the exchangeable and mildly acidic steps for the bulk dusts collected from four smelter areas. The later steps of the extraction procedure were more effective in dissolving the lead compounds associated with the bulk dust samples, with 43%, 26%, and 8% of the total lead, in the ore storage, sinter, and blast/dross smelter areas, respectively, being extracted in the residual step. Sequential extraction of coarse airborne dust samples from the ore storage and sinter plant showed that 1.2% and 4.1% of the total lead, respectively, was exchangeable. The finer particle size fractions from these areas of the smelter showed higher percentages of exchangeable lead. Of the course airborne dust from the blast/dross furnace processes, 65% of the total lead was exchangeable. However, the largest percentage of lead from these areas was associated with the finer particle-size fractions. If lead bioavailability is related to its solubility as determined through sequential extraction, the health hazards associated with lead exposure may be appreciably enhanced in the blast and dross furnace processes. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:9721256

  9. Airborne particulate matter in spacecraft

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Acceptability limits and sampling and monitoring strategies for airborne particles in spacecraft were considered. Based on instances of eye and respiratory tract irritation reported by Shuttle flight crews, the following acceptability limits for airborne particles were recommended: for flights of 1 week or less duration (1 mg/cu m for particles less than 10 microns in aerodynamic diameter (AD) plus 1 mg/cu m for particles 10 to 100 microns in AD); and for flights greater than 1 week and up to 6 months in duration (0.2 mg/cu m for particles less than 10 microns in AD plus 0.2 mg/cu m for particles 10 to 100 microns in AD. These numerical limits were recommended to aid in spacecraft atmosphere design which should aim at particulate levels that are a low as reasonably achievable. Sampling of spacecraft atmospheres for particles should include size-fractionated samples of 0 to 10, 10 to 100, and greater than 100 micron particles for mass concentration measurement and elementary chemical analysis by nondestructive analysis techniques. Morphological and chemical analyses of single particles should also be made to aid in identifying airborne particulate sources. Air cleaning systems based on inertial collection principles and fine particle collection devices based on electrostatic precipitation and filtration should be considered for incorporation into spacecraft air circulation systems. It was also recommended that research be carried out in space in the areas of health effects and particle characterization.

  10. Lagrangian dust model simulations for a case of moist convective dust emission and transport in the western Sahara region during Fennec/LADUNEX

    NASA Astrophysics Data System (ADS)

    Sodemann, H.; Lai, T. M.; Marenco, F.; Ryder, C. L.; Flamant, C.; Knippertz, P.; Rosenberg, P.; Bart, M.; McQuaid, J. B.

    2015-06-01

    Due to the harshness and inaccessibility of desert regions, the uncertainties concerning the processes of dust mobilization at the surface, airborne transport, and sedimentation are still considerable, limiting the ability to perform model simulations. In June 2011, a comprehensive data set of ground-based and airborne in situ measurements and remote sensing observations was acquired within the Fennec/Lagrangian Dust Source Inversion Experiment (LADUNEX) field campaign in the western Sahara region. Here we evaluate the ability of the state-of-the-art Lagrangian particle dispersion model FLEXPART, newly fitted with a dust mobilization capability, to simulate dust transport in this region. We investigate a case where a large mesoscale convective system (MCS) triggered dust emissions in central Mali, which subsequently moved as a large cold pool dust front toward northern Mauritania. Specifying dust mobilization for this case is shown to be an important obstacle to simulating dust transport during this event, since neither the MCS nor the associated cold pool-causing dust emission is represented in the meteorological analysis. Obtaining a realistic dust transport simulation for this case therefore requires an inversion approach using a manual specification of the dust sources supported by satellite imagery. When compared to in situ and remote sensing data from two aircraft, the Lagrangian dust transport simulations represent the overall shape and evolution of the dust plume well. While accumulation and coarse mode dust are well represented in the simulation, giant mode particles are considerably underestimated. Our results re-emphasize that dust emission associated with deep moist convection remains a key issue for reliable dust model simulations in northern Africa.

  11. Exposure to soil, house dust and decaying plants increases gut microbial diversity and decreases serum immunoglobulin E levels in BALB/c mice.

    PubMed

    Zhou, Dongrui; Zhang, Honglin; Bai, Zhimao; Zhang, Aidi; Bai, Futian; Luo, Xing; Hou, Yue; Ding, Xiao; Sun, Beili; Sun, Xiao; Ma, Ning; Wang, Cuifen; Dai, Xiaoniu; Lu, Zuhong

    2016-05-01

    To assess the impact of sanitation of a living environment on gut microbiota and development of the immune system, we raised BALB/c mice under three distinct environmental conditions: a specific pathogen-free animal room (SPF), a general animal room (XZ) and a farmhouse (JD). All other variables like diet, age, genetic background, physiological status and original gut microbiota were controlled for in the three groups. Using high-throughput sequencing of the 16S rRNA gene, we found that each mouse group had a specific structure of the gut microbial community. Groups JD and XZ harboured a significantly more diverse and richer gut microbiota than did group SPF. Bacteroidetes were significantly more abundant in groups XZ and JD than in group SPF, whereas Firmicutes showed the inverse pattern. Total serum immunoglobulin E (IgE) levels were significantly lower in groups XZ and JD than in group SPF. There were no significant differences in gut microbiota diversity and serum IgE concentration between groups JD and XZ, but we found higher abundance of dominant genera in the gut microflora of group JD. We conclude that exposure to soil, house dust and decaying plant material enhances gut microbial diversity and innate immunity. Our results seem to provide new evidence supporting the hygiene hypothesis. PMID:25958920

  12. Toolsets for Airborne Data

    Atmospheric Science Data Center

    2015-04-02

    article title:  Toolsets for Airborne Data     View larger image The ... limit of detection values. Prior to accessing the TAD Web Application ( https://tad.larc.nasa.gov ) for the first time, users must ...

  13. Exposure to Bioaerosols in Poultry Houses at Different Stages of Fattening; Use of Real-time PCR for Airborne Bacterial Quantification

    PubMed Central

    Oppliger, Anne; Charrière, Nicole; Droz, Pierre-Olivier; Rinsoz, Thomas

    2008-01-01

    Previous studies have demonstrated that poultry house workers are exposed to very high levels of organic dust and consequently have an increased prevalence of adverse respiratory symptoms. However, the influence of the age of broilers on bioaerosol concentrations has not been investigated. To evaluate the evolution of bioaerosol concentration during the fattening period, bioaerosol parameters (inhalable dust, endotoxin and bacteria) were measured in 12 poultry confinement buildings in Switzerland, at three different stages of the birds’ growth; samples of air taken from within the breathing zones of individual poultry house employees as they caught the chickens ready to be transported for slaughter were also analysed. Quantitative polymerase chain reaction (Q-PCR) was used to assess the quantity of total airborne bacteria and total airborne Staphylococcus species. Bioaerosol levels increased significantly during the fattening period of the chickens. During the task of catching mature birds, the mean inhalable dust concentration for a worker was 26 ± 1.9 mg m−3 and endotoxin concentration was 6198 ± 2.3 EU m−3 air, >6-fold higher than the Swiss occupational recommended value (1000 EU m−3). The mean exposure level of bird catchers to total bacteria and Staphylococcus species measured by Q-PCR is also very high, respectively, reaching values of 53 (±2.6) × 107 cells m−3 air and 62 (±1.9) × 106 m−3 air. It was concluded that in the absence of wearing protective breathing apparatus, chicken catchers in Switzerland risk exposure beyond recommended limits for all measured bioaerosol parameters. Moreover, the use of Q-PCR to estimate total and specific numbers of airborne bacteria is a promising tool for evaluating any modifications intended to improve the safety of current working practices. PMID:18497431

  14. Sensitivities of five alpha continuous air monitors for detection of airborne sup 239 Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  15. Sensitivities of five alpha continuous air monitors for detection of airborne {sup 239}Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  16. The airborne laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven; Schall, Harold; Shattuck, Paul

    2007-05-01

    The Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the current program status.

  17. A Review on the Importance of Metals and Metalloids in Atmospheric Dust and Aerosol from Mining Operations

    PubMed Central

    Csavina, Janae; Field, Jason; Taylor, Mark P.; Gao, Song; Landázuri, Andrea; Betterton, Eric A.; Sáez, A. Eduardo

    2012-01-01

    Contaminants can be transported rapidly and over relatively long distances by atmospheric dust and aerosol relative to other media such as water, soil and biota; yet few studies have explicitly evaluated the environmental implications of this pathway, making it a fundamental but understudied transport mechanism. Although there are numerous natural and anthropogenic activities that can increase dust and aerosol emissions and contaminant levels in the environment, mining operations are notable with respect to the quantity of particulates generated, the global extent of area impacted, and the toxicity of contaminants associated with the emissions. Here we review (i) the environmental fate and transport of metals and metalloids in dust and aerosol from mining operations, (ii) current methodologies used to assess contaminant concentrations and particulate emissions, and (iii) the potential health and environmental risks associated with airborne contaminants from mining operations. The review evaluates future research priorities based on the available literature and suggest that there is a particular need to measure and understand the generation, fate and transport of airborne particulates from mining operations, specifically the finer particle fraction. More generally, our findings suggest that mining operations play an important but underappreciated role in the generation of contaminated atmospheric dust and aerosol and the transport of metal and metalloid contaminants, and highlight the need for further research in this area. The role of mining activities in the fate and transport of environmental contaminants may become increasingly important in the coming decades, as climate change and land use are projected to intensify, both of which can substantially increase the potential for dust emissions and transport. PMID:22766428

  18. Dimethylarginine dimethylaminohydrolase (DDAH) overexpression attenuates agricultural organic dust extract-induced inflammation

    PubMed Central

    Bailey, KL; Wyatt, TA; Wells, SM; Klein, EB; Robinson, JE; Romberger, DJ; Poole, JA

    2013-01-01

    Modern, industrialized farming practices have lead to working conditions that include high levels of airborne dust. Agricultural workers inhale these complex organic dusts on a daily basis, leading to airway inflammation and higher risk for developing chronic obstructive pulmonary disease. The mechanisms regulating the organic dust-induced airway inflammatory response are not well-defined. We investigated whether overexpression of dimethylarginine dimethylaminohydrolase (DDAH) would lead to diminished pulmonary inflammation in an animal model of organic dust extract exposure. We instilled wild-type (WT) and DDAH overexpressing mice with an aqueous organic dust extract (ODE) collected from a swine confinement building. We found that inflammatory indices such as neutrophil influx and inflammatory cytokine production was lower in the DDAH overexpressing mice compared to WT after organic dust extract (ODE) instillation. We went on to determine how DDAH was mediating the decrease in inflammation induced by ODE. PKCα and PKCε play an essential role in the ODE inflammatory response. In a model of lung slices from WT and DDAH overexpressing mice, we demonstrated an increase in PKCα and PKCε in the WT mice exposed to ODE. This increase was diminished in the DDAH overexpressing mice exposed to ODE. We also tested an important component of the ODE, peptidoglycan (PGN). We noted a similar decrease in neutrophils and inflammatory cytokines in the DDAH overexpressing animals instilled with PGN compared to WT. In conclusion, our studies found a role for DDAH in regulating the ODE-triggered activation of epithelial PKCα and PKCε, a previously unrecognized mechanism of action. This ultimately results in diminished pulmonary inflammation. PMID:25221746

  19. Physicochemical Characterization of Aeolian Mine Tailings Dust in the Southwest USA

    NASA Astrophysics Data System (ADS)

    Betterton, E. A.; Barbaris, B.; Conant, W.; Csavina, J.; Gao, S.; Lund, L.; Rheinheimer, P.; Saez, E.; Wonaschutz, A.

    2008-12-01

    Census data reveal that the Southwest is the fastest growing region of the USA, while NOAA GFDL coupled- model results suggest that precipitation is expected to decline in the same region over the coming decades. Besides the obvious impact on water resources, the drier conditions will most likely also result in increased atmospheric dust loads that could impact the health of a rapidly increasing population. This year the US EPA began site assessment and remediation at two mine tailings piles in Arizona contaminated with arsenic, lead, chromium and cadmium. The first is located in the twin towns of Hayden and Winkleman, and the second at the Iron King mine near Humbolt. At a concentration of approximately 0.1 microgram per cubic meter, the level of arsenic in PM10 collected at Hayden/Winkelman sometimes exceeds the Arizona ambient hazardous air pollutant standard (HAPS) by several orders of magnitude. Lead, cadmium and chromium are also sometimes orders of magnitude higher than the HAPS. A top priority is to determine the physicochemical speciation of wind-blown dust as a function of particle diameter because this information can a) help with source apportionment of airborne pollutants (e.g., smelter emissions vs. tailings dust), and b) help to assess the potential health impacts of contaminated dust, since deposition efficiency in human lungs is a strong function of particle diameter. We will present the chemical and physical characteristics of mine tailings dust collected with 10-stage multiple orifice uniform deposit impactors (MOUDI) located at Hayden/Winkleman and Iron King. We will also present scanning mobility particle spectrometer (SMPS) data obtained from the same sites. The MOUDI yields particle composition by size fraction (0.056-18 micrometer aerodynamic diameter) while the SMPS yields particle number by size fraction (0.0025 to 1.0 micrometer diameter). Size selective characteristics such as these have never been previously reported for mine tailings

  20. Polybrominated diphenyl ethers (PBDEs) in soil and outdoor dust from a multi-functional area of Shanghai: levels, compositional profiles and interrelationships.

    PubMed

    Wu, Ming-Hong; Pei, Jing-Cheng; Zheng, Ming; Tang, Liang; Bao, Yang-Yang; Xu, Ben-Tuo; Sun, Rui; Sun, Yan-Feng; Xu, Gang; Lei, Jian-Qiu

    2015-01-01

    In this study, 14 polybrominated diphenyl ethers (PBDEs) congeners were investigated in soil and outdoor dust taken from Jiading District, Shanghai City. The concentrations of Σ13PBDEs (BDE-17, BDE-28, BDE-47, BDE-66, BDE-71, BDE-85, BDE-99, BDE-100, BDE-138, BDE-153, BDE-154, BDE-183 and BDE-190) and BDE-209 ranged from 0.37 to 32.9ngg(-1) and 4.31 to 141.8ngg(-1) dry weight (dw) in soil. Concentrations in outdoor dust ranged from 1.03 to 112.5ngg(-1) and 6.71 to 342.1ngg(-1) (dw) for Σ13PBDEs and BDE-209. BDE-209 was the predominant congener both in soil and outdoor dust, but the BDE-209 contribution was much lower in dust compared with that in soil. A significant correlation between PBDEs congeners and specific land use type was observed, and principal component analysis (PCA) revealed that the major source of PBDE in samples was associated with prevalent use of technical Deca-BDE, which also suggested the contributions from Penta-BDE and Octa-BDE mixtures. Canonical correlation analysis suggested the two sets of PBDEs data (soil and outdoor dust) were uncorrelated, and Spearman correlation coefficient matrix implied that the degradation pathways of PBDEs were different between soil and outdoor dust. PMID:25033108

  1. Respiratory disorders associated with heavy inhalation exposure to dolomite dust

    PubMed Central

    Neghab, M; Abedini, R; Soltanzadeh, A; Iloon Kashkooli, A; Ghayoomi, S M A

    2012-01-01

    Background Although dolomite is classified as a relatively non-toxic, nuisance dust, little information exists as to its potential to produce respiratory disorders following occupational exposure. The purpose of this study was, therefore, to evaluate the possible effects, if any, of heavy inhalation exposure to this chemical on the prevalence of respiratory symptoms, functional impairments and radiographic abnormalities of the lungs. Methods The study population consisted of a group of 39 exposed subjects engaged in digging and excavating activities that were in operation for building a local dam, as well as 40 healthy non-exposed employees that served as the referent group. Subjects were interviewed and respiratory symptoms questionnaires, as suggested by the American Thoracic Society (ATS), were completed for them. Thereafter, they underwent chest X-ray and lung function tests. Additionally, using routine gravimetric techniques, personal dust monitoring for airborne inhalable and respirable dust was carried out at different dusty work sites. Finally to determine the chemical composition of the dust, it was analyzed by X-ray fluorescence (XRF) technique. Results XRF revealed that the major component (50.52%) of the dust was calcium magnesium carbonate, dolomite. Additionally, levels of exposure to inhalable and respirable dust were estimated to be 51.7±24.31 and 23.0±18.11mg/m3, respectively. Statistical analysis of the data showed that symptoms such as regular cough, phlegm, wheezing, productive cough and shortness of breath were significantly (p<0.05) more prevalent among exposed workers. Similarly, the ratio of FEV1/FVC in exposed subjects was significantly different from that of non-exposed individuals. In contrast, no significant abnormalities were observed in the chest radiographs of both groups. Conclusions In conclusion, while these data cast doubt on the notion that dolomite is a harmless chemical, they provide evidence in favour of the proposition that

  2. Saharan dust episodes and pregnancy.

    PubMed

    Dadvand, Payam; Basagaña, Xavier; Figueras, Francesc; Amoly, Elmira; Tobias, Aurelio; de Nazelle, Audrey; Querol, Xavier; Sunyer, Jordi; Nieuwenhuijsen, Mark J

    2011-11-01

    Desert dust is one of the natural contributors to atmospheric particulate matter worldwide. Although particulate pollution has been shown to adversely affect pregnancy, the available evidence on the impact of dust episodes on pregnancy is very scarce. The aim of this study was to evaluate the impact of Saharan dust episodes on pregnancy complications (preeclampsia and bacteriuria) and outcomes (birth weight and gestational age at delivery). This study was based on a cohort of births (N = 3565) that occurred in a major university hospital in Barcelona during 2003-2005. To determine Saharan dust episodes, we developed a two-stage approach based on meteorological evidence of the presence of Saharan dust cloud over the region and unusually high levels of particulate levels on the ground while taking account of traffic sources. The associations between the number of Saharan dust episodes during whole pregnancy as well as each pregnancy trimester and pregnancy complications and outcomes were analysed. There were 152 days (out of 838 days) with Saharan dust cloud over the region from which 45 days were determined as episodic days. We did not observe any statistically significant harmful effect of Saharan dust episodes on our included pregnancy complications and outcomes. However, we observed a small but statistically significant increase in gestational age at delivery in association with the number of episodic days during the third trimester and whole pregnancy (0.8 and 0.5 days respectively). Our findings were not suggestive for any adverse effect of Saharan dust episodes on our included pregnancy complications and outcomes. PMID:21964628

  3. Dust Spectroscopy and the Nature of Grains

    NASA Technical Reports Server (NTRS)

    Tielens, A. G. G. M.

    2006-01-01

    Ground-based, air-borne and space-based, infrared spectra of a wide variety of objects have revealed prominent absorption and emission features due to large molecules and small dust grains. Analysis of this data reveals a highly diverse interstellar and circumstellar grain inventory, including both amorphous materials and highly crystalline compounds (silicates and carbon). This diversity points towards a wide range of physical and chemical birthsites as well as a complex processing of these grains in the interstellar medium. In this talk, I will review the dust inventory contrasting and comparing both the interstellar and circumstellar reservoirs. The focus will be on the processes that play a role in the lifecycle of dust in the interstellar medium.

  4. Airborne rescue system

    NASA Technical Reports Server (NTRS)

    Haslim, Leonard A. (Inventor)

    1991-01-01

    The airborne rescue system includes a boom with telescoping members for extending a line and collar to a rescue victim. The boom extends beyond the tip of the helicopter rotor so that the victim may avoid the rotor downwash. The rescue line is played out and reeled in by winch. The line is temporarily retained under the boom. When the boom is extended, the rescue line passes through clips. When the victim dons the collar and the tension in the line reaches a predetermined level, the clips open and release the line from the boom. Then the rescue line can form a straight line between the victim and the winch, and the victim can be lifted to the helicopter. A translator is utilized to push out or pull in the telescoping members. The translator comprises a tape and a rope. Inside the telescoping members the tape is curled around the rope and the tape has a tube-like configuration. The tape and rope are provided from supply spools.

  5. Dust Model Intercomparison For Summer 2012 In The Western Mediterranean and Comparison to The Pre-ChArMEx/TRAQA Campaign Observations

    NASA Astrophysics Data System (ADS)

    Basart, Sara

    2014-05-01

    Saharan dust is an important contributor on European air quality levels and consequently has a relevant impact on human health and ecosystems. Even though most of the transport of dust particles occurs in altitude, as shown by surface lidars and airborne data, dust events signi?cantly impact surface PM10 concentrations even in urban traf?c type of air quality monitoring stations, and background stations are needed to assess the contribution of desert dust. In this sense, regional air quality models are useful to understand the dynamics and transport of pollutants. The present contribution shows a preliminary intercomparison of a set of 7 regional dust model simulations (NMMB/BSC-Dust, ALADIN, Meso-NH, RegCM, CHIMERE, COSMO/MUSCAT; MOCAGE and BSC-DREAM8b). The present analysis focuses on the model capability to properly simulate long-range Saharan dust transport for summer 2012 in the Western Mediterranean. In this period, Saharan dust events were numerous as shown by satellite and ground-based observations. The model evaluation is crucial to determine the individual performance of each model and it provides a useful tool to identify their strengths and weaknesses. In this study, the model outputs are compared against a variety of both ground-based and airborne in situ and remote sensing measurements performed during the pre-ChArMEx/TRAQA ?eld campaign which included the airborne lidar LNG and the new balloonborne optical particle counter LOAC. Also, the models are compared with satellite aerosol products (including MSG/SEVIRI, POLDER and CALIOP) which provide a description of the spatial AOD distribution over the basin. These observational datasets provide a complete set of unusual quantitative constraints for model simulations of this period, combining data on aerosol optical depth, vertical distribution, particle size distribution, and chemical and optical properties. Acknowledgements are addressed to OMP/SEDOO for the ChArMEx data portal and to CNES for balloon

  6. Manganese and lead in dust fall accumulation in elementary schools near a ferromanganese alloy plant.

    PubMed

    Menezes-Filho, José Antonio; Souza, Karine O Fraga de; Rodrigues, Juliana L Gomes; Santos, Nathália Ribeiro Dos; Bandeira, Matheus de Jesus; Koin, Ng Lai; Oliveira, Sérgio S do Prado; Godoy, Ana Leonor P Campos; Mergler, Donna

    2016-07-01

    Previous studies have shown elevated airborne manganese (Mn) in villages adjacent to a Mn alloy production plant in Brazil and negative associations between biomarkers of Mn and children's cognition and behavior. Since small Mn particles may be carried for long distances, we measured manganese (Mn) and lead (Pb) dust fall accumulation in 15 elementary schools, located between 1.25 and 6.48km from the plant in the municipality of Simões Filho, Bahia, Brazil. Passive samplers (polyethylene Petri dishes) were set in interior and exterior environments. After 30 days, the samplers' content was solubilized with diluted nitric acid and Mn and Pb levels were analyzed by electrothermal absorption spectrometry. The overall geometric mean and range of Mn and Pb accumulation in dust fall (loading rates) were 1582μg Mn/m(2)/30 days (37-37,967) and 43.2μg Pb/m(2)/30 days (2.9-210.4). A logarithmic decrease in interior and exterior Mn loading rates was observed with distance from the ferro-manganese alloy plant. Multiple regression analyses of log-transformed Mn loading rate within the schools showed a positive association with Mn levels in outdoor dust, a negative association with distance from the plant; as well, wind direction (downwind>upwind) and school location (urban>rural) entered significantly into the model. For the interior school environments, located within a 2-km radius from the plant, loading rate was, on average, 190 times higher than the Mn levels reported by Gulson et al., (2014) in daycare centers in Sydney, Australia, using a similar method. Pb loading rates were not associated with distance from the plant and were lower than the rates observed in the same daycare centers in Sydney. Our findings suggest that a significant portion of the children in this town in Brazil may be exposed to airborne Mn at concentrations that may affect their neurodevelopment. PMID:27107708

  7. Mechanisms for Mars dust storms.

    NASA Technical Reports Server (NTRS)

    Leovy, C. B.; Zurek, R. W.; Pollack, J. B.

    1973-01-01

    Characteristics of the Mars global dust storm are reviewed. At the Mariner 9 encounter, the dust consisted of highly absorbing particles distributed rather uniformly up to great height (about 50 km). These observations together with temperature distributions inferred from the Mariner 9 IRIS by Hanel et al. (1972) are used to estimate global wind systems during the dust storm. The global distribution and direction of light surface streaks indicate that the axisymmetric circulation was a dominant part of flow during the dust storm. The axisymmetric winds may become strong enough to raise dust over wide areas of Mars' tropics under unusual conditions: the incoming solar radiation must be near its seasonal maximum, the static stability must be low, and the atmosphere must be able to absorb and re-emit a sizeable fraction of the incoming radiation. Strong winds around the periphery of the retreating south polar cap would be driven by the temperature gradient at the cap edge and by the mass outflow due to subliming CO2. These polar winds could generate local dust storms, raising the general level of dustiness, and providing the conditions necessary for onset of a global dust storm.

  8. Iron Speciation in Urban Dust

    SciTech Connect

    E Elzinga; Y Gao; J Fitts; R Tappero

    2011-12-31

    An improved understanding of anthropogenic impacts on ocean fertility requires knowledge of anthropogenic dust mineralogy and associated Fe speciation as a critical step toward developing Fe solubility models constrained by mineralogical composition. This study explored the utility of micro-focused X-ray absorption spectroscopy ({mu}-XAS) in characterizing the speciation of Fe in urban dust samples. A micro-focused beam of 10 x 7 {micro}m made possible the measurement of the Fe K edge XAS spectra of individual dust particles in the PM5.6 size fraction collected in Newark, New Jersey, USA. Spectral analysis indicated the presence of mixtures of Fe-containing minerals within individual dust particles; we observed significant magnetite content along with other Fe(III)-(hydr)oxide minerals which could not be conclusively identified. Our data indicate that detailed quantitative determination of Fe speciation requires extended energy scans to constrain the types and relative abundance of Fe species present. We observe heterogeneity in Fe speciation at the dust particle level, which underscores the importance of analyzing a statistically adequate number of particles within each dust sample. Where possible, {mu}-XAS measurements should be complemented with additional characterization techniques such as {mu}-XRD and bulk XAS to obtain a comprehensive picture of the Fe speciation in dust materials. X-ray microprobes should be used to complement bulk methods used to determine particle composition, methods that fail to record particle heterogeneity.

  9. Pollution Characteristics and Health Risk Assessment of Airborne Heavy Metals Collected from Beijing Bus Stations.

    PubMed

    Zheng, Xiaoxia; Zhao, Wenji; Yan, Xing; Shu, Tongtong; Xiong, Qiulin; Chen, Fantao

    2015-08-01

    Airborne dust, which contains high levels of toxic metals, is recognized as one of the most harmful environment component. The purpose of this study was to evaluate heavy metals pollution in dustfall from bus stations in Beijing, and to perform a risk assessment analysis for adult passengers. The concentrations of Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn were determined by inductively coupled plasma mass spectroscopy (ICP-MS). The spatial distribution, pollution level and potential health risk of heavy metals were analyzed by Geographic Information System (GIS) mapping technology, geo-accumulation index and health risk assessment model, respectively. The results indicate that dust samples have elevated metal concentrations, especially for Cd, Cu, Pb and Zn. The nine metals can be divided into two categories in terms of spatial distribution and pollution level. Cd, Cr, Cu, Mo, Pb and Zn reach contaminated level and have similar spatial patterns with hotspots distributed within the Fifth Ring Road. While the hot spot areas of Co and V are always out of the Fifth Ring Road. Health risk assessment shows that both carcinogenic and non-carcinogenic risks of selected metals were within the safe range. PMID:26287229

  10. Pollution Characteristics and Health Risk Assessment of Airborne Heavy Metals Collected from Beijing Bus Stations

    PubMed Central

    Zheng, Xiaoxia; Zhao, Wenji; Yan, Xing; Shu, Tongtong; Xiong, Qiulin; Chen, Fantao

    2015-01-01

    Airborne dust, which contains high levels of toxic metals, is recognized as one of the most harmful environment component. The purpose of this study was to evaluate heavy metals pollution in dustfall from bus stations in Beijing, and to perform a risk assessment analysis for adult passengers. The concentrations of Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn were determined by inductively coupled plasma mass spectroscopy (ICP-MS). The spatial distribution, pollution level and potential health risk of heavy metals were analyzed by Geographic Information System (GIS) mapping technology, geo-accumulation index and health risk assessment model, respectively. The results indicate that dust samples have elevated metal concentrations, especially for Cd, Cu, Pb and Zn. The nine metals can be divided into two categories in terms of spatial distribution and pollution level. Cd, Cr, Cu, Mo, Pb and Zn reach contaminated level and have similar spatial patterns with hotspots distributed within the Fifth Ring Road. While the hot spot areas of Co and V are always out of the Fifth Ring Road. Health risk assessment shows that both carcinogenic and non-carcinogenic risks of selected metals were within the safe range. PMID:26287229

  11. A Fractal Model for the Capacitance of Lunar Dust and Lunar Dust Aggregates

    NASA Technical Reports Server (NTRS)

    Collier, Michael R.; Stubbs, Timothy J.; Keller, John W.; Farrell, William M.; Marshall, John; Richard, Denis Thomas

    2011-01-01

    Lunar dust grains and dust aggregates exhibit clumping, with an uneven mass distribution, as well as features that span many spatial scales. It has been observed that these aggregates display an almost fractal repetition of geometry with scale. Furthermore, lunar dust grains typically have sharp protrusions and jagged features that result from the lack of aeolian weathering (as opposed to space weathering) on the Moon. A perfectly spherical geometry, frequently used as a model for lunar dust grains, has none of these characteristics (although a sphere may be a reasonable proxy for the very smallest grains and some glasses). We present a fractal model for a lunar dust grain or aggregate of grains that reproduces (1) the irregular clumpy nature of lunar dust, (2) the presence of sharp points, and (3) dust features that span multiple scale lengths. We calculate the capacitance of the fractal lunar dust analytically assuming fixed dust mass (i.e. volume) for an arbitrary number of fractal levels and compare the capacitance to that of a non-fractal object with the same volume, surface area, and characteristic width. The fractal capacitance is larger than that of the equivalent non-fractal object suggesting that for a given potential, electrostatic forces on lunar dust grains and aggregates are greater than one might infer from assuming dust grains are sphericaL Consequently, electrostatic transport of lunar dust grains, for example lofting, appears more plausible than might be inferred by calculations based on less realistic assumptions about dust shape and associated capacitance.

  12. Pulmonary Toxicity Studies of Lunar Dusts in Rodents

    NASA Technical Reports Server (NTRS)

    Lam, Chiu-wing; James, John T.; Taylor, Larry

    2008-01-01

    NASA will build an outpost on the lunar surface for long-duration human habitation and research. The surface of the Moon is covered by a layer of fine, reactive dust, and the living quarters in the lunar outpost are expected to be contaminated by lunar dust. NASA established the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) to evaluate the risk of exposure to the dust and to establish safe exposure limits for astronauts working in the lunar habitat. Because the toxicity of lunar dust is not known, LADTAG has recommended investigating its toxicity in the lungs of laboratory animals. After receiving this recommendation, NASA directed the JSC Toxicology Laboratory to determine the pulmonary toxicity of lunar dust in exposed rodents. The rodent pulmonary toxicity studies proposed here are the same as those proposed by the LADTAG. Studies of the pulmonary toxicity of a dust are generally done first in rodents by intratracheal instillation (ITI). This toxicity screening test is then followed by an inhalation study, which requires much more of the test dust and is labor intensive. We succeeded in completing an ITI study on JSC-1 lunar dust simulant in mice (Lam et al., Inhalation Toxicology 14:901-916, 2002, and Inhalation Toxicology 14: 917-928, 2002), and have conducted a pilot ITI study to examine the acute toxicity of an Apollo lunar (highland) dust sample. Preliminary results obtained by examining lung lavage fluid from dust-treated mice show that lunar dust was somewhat toxic (more toxic than TiO2, but less than quartz dust). More extensive studies have been planned to further examine lung lavage fluid for biomarkers of toxicity and lung tissues for histopathological lesions in rodents exposed to aged and activated lunar dust samples. In these studies, reference dusts (TiO2 and quartz) of known toxicities and have industrial exposure limits will be studied in parallel so the relative toxicity of lunar dust can be determined. The ITI results will also be

  13. Active airborne contamination control using electrophoresis

    SciTech Connect

    Veatch, B.D.

    1994-06-01

    In spite of our best efforts, radioactive airborne contamination continues to be a formidable problem at many of the Department of Energy (DOE) weapons complex sites. For workers that must enter areas with high levels of airborne contamination, personnel protective equipment (PPE) can become highly restrictive, greatly diminishing productivity. Rather than require even more restrictive PPE for personnel in some situations, the Rocky Flats Plant (RFP) is actively researching and developing methods to aggressively combat airborne contamination hazards using electrophoretic technology. With appropriate equipment, airborne particulates can be effectively removed and collected for disposal in one simple process. The equipment needed to implement electrophoresis is relatively inexpensive, highly reliable, and very compact. Once airborne contamination levels are reduced, less PPE is required and a significant cost savings may be realized through decreased waste and maximized productivity. Preliminary ``cold,`` or non-radioactive, testing results at the RFP have shown the technology to be effective on a reasonable scale, with several potential benefits and an abundance of applications.

  14. Pulmonary Toxicity Studies of Lunar Dusts in Rodents

    NASA Technical Reports Server (NTRS)

    Lam, C.-W.; James, J. T.; Taylor, L.; Zeidler-Erdely, P. C.; Castranova, V.

    2009-01-01

    NASA will build an outpost on the Moon for prolonged human habitation and research. The lunar surface is covered by a layer of fine, reactive dust. Astronauts on the Moon will go in and out of the base for various activities, and will inevitably bring some dust into the living quarters. Depressurizing the airlock so that astronauts can exit for outdoor activities could also bring dust inside the airlock to the habitable area. Concerned about the potential health effects on astronauts exposed to airborne lunar dust, NASA directed the JSC Toxicology Laboratory to determine the pulmonary toxicity of lunar dust. The toxicity data also will be needed by toxicologists to establish safe exposure limits for astronauts residing in the lunar habitat and by environmental engineers to design an appropriate dust mitigation strategy. We conducted a study to examine biomarkers of toxicity (inflammation and cytotoxicity) in lung lavage fluids from mice intrapharyngeally instilled with lunar dust samples; we also collected lung tissue from the mice for histopathological examination 3 months after the dust instillation. Reference dusts (TiO2 and quartz) having known toxicities and industrial exposure limits were studied in parallel with lunar dust so that the relative toxicity of lunar dust can be determined. A 6-month histopathology study has been planned. These instillation experiments will be followed by inhalation studies, which are more labor intensive and technologically difficult. The animal inhalation studies will be conducted first with an appropriate lunar dust simulant to ensure that the exposure techniques to be used with actual lunar dust will be successful. The results of these studies collectively will reveal the toxicological risk of exposures and enable us to establish exposure limits on lunar dust for astronauts living in the lunar habitat.

  15. Short-term variability of mineral dust, metals and carbon emission from road dust resuspension

    NASA Astrophysics Data System (ADS)

    Amato, Fulvio; Schaap, Martijn; Denier van der Gon, Hugo A. C.; Pandolfi, Marco; Alastuey, Andrés; Keuken, Menno; Querol, Xavier

    2013-08-01

    Particulate matter (PM) pollution in cities has severe impact on morbidity and mortality of their population. In these cities, road dust resuspension contributes largely to PM and airborne heavy metals concentrations. However, the short-term variation of emission through resuspension is not well described in the air quality models, hampering a reliable description of air pollution and related health effects. In this study we experimentally show that the emission strength of resuspension varies widely among road dust components/sources. Our results offer the first experimental evidence of different emission rates for mineral dust, heavy metals and carbon fractions due to traffic-induced resuspension. Also, the same component (or source) recovers differently in a road in Barcelona (Spain) and a road in Utrecht (The Netherlands). This finding has important implications on atmospheric pollution modelling, mostly for mineral dust, heavy metals and carbon species. After rain events, recoveries were generally faster in Barcelona rather than in Utrecht. The largest difference was found for the mineral dust (Al, Si, Ca). Tyre wear particles (organic carbon and zinc) recovered faster than other road dust particles in both cities. The source apportionment of road dust mass provides useful information for air quality management.

  16. Airborne Aerosol Closure Studies During PRIDE

    NASA Technical Reports Server (NTRS)

    Redemann, Jens; Livingston, John M.; Russell, Philip B.; Schmid, Beat; Reid, Jeff

    2000-01-01

    The Puerto Rico Dust Experiment (PRIDE) was conducted during June/July of 2000 to study the properties of Saharan dust aerosols transported across the Atlantic Ocean to the Caribbean Islands. During PRIDE, the NASA Ames Research Center six-channel (380 - 1020 nm) airborne autotracking sunphotometer (AATS-6) was operated aboard a Piper Navajo airplane alongside a suite of in situ aerosol instruments. The in situ aerosol instrumentation relevant to this paper included a Forward Scattering Spectrometer Probe (FSSP-100) and a Passive Cavity Aerosol Spectrometer Probe (PCASP), covering the radius range of approx. 0.05 to 10 microns. The simultaneous and collocated measurement of multi-spectral aerosol optical depth and in situ particle size distribution data permits a variety of closure studies. For example, vertical profiles of aerosol optical depth obtained during local aircraft ascents and descents can be differentiated with respect to altitude and compared to extinction profiles calculated using the in situ particle size distribution data (and reasonable estimates of the aerosol index of refraction). Additionally, aerosol extinction (optical depth) spectra can be inverted to retrieve estimates of the particle size distributions, which can be compared directly to the in situ size distributions. In this paper we will report on such closure studies using data from a select number of vertical profiles at Cabras Island, Puerto Rico, including measurements in distinct Saharan Dust Layers. Preliminary results show good agreement to within 30% between mid-visible aerosol extinction derived from the AATS-6 optical depth profiles and extinction profiles forward calculated using 60s-average in situ particle size distributions and standard Saharan dust aerosol refractive indices published in the literature. In agreement with tendencies observed in previous studies, our initial results show an underestimate of aerosol extinction calculated based on the in situ size distributions

  17. Dust agglomeration

    NASA Technical Reports Server (NTRS)

    2000-01-01

    John Marshall, an investigator at Ames Research Center and a principal investigator in the microgravity fluid physics program, is studying the adhesion and cohesion of particles in order to shed light on how granular systems behave. These systems include everything from giant dust clouds that form planets to tiny compressed pellets, such as the ones you swallow as tablets. This knowledge should help us control the grains, dust, and powders that we encounter or use on a daily basis. Marshall investigated electrostatic charge in microgravity on the first and second U.S. Microgravity Laboratory shuttle missions to see how grains aggregate, or stick together. With gravity's effects eliminated on orbit, Marshall found that the grains of sand that behaved ever so freely on Earth now behaved like flour. They would just glom together in clumps and were quite difficult to disperse. That led to an understanding of the prevalence of the electrostatic forces. The granules wanted to aggregate as little chains, like little hairs, and stack end to end. Some of the chains had 20 or 30 grains. This phenomenon indicated that another force, what Marshall believes to be an electrostatic dipole, was at work.(The diagram on the right emphasizes the aggregating particles in the photo on the left, taken during the USML-2 mission in 1995.)

  18. Canyon Dust

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03682 Canyon Dust

    These dust slides are located on the wall of Thithonium Chasma.

    Image information: VIS instrument. Latitude -4.1N, Longitude 275.7E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  19. Dust Slides

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03677 Linear Clouds

    Dust slides are common in the dust covered region called Lycus Sulci. A large fracture is also visible in this image.

    Image information: VIS instrument. Latitude 28.1N, Longitude 226.3E. 18 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  20. Dust collector

    SciTech Connect

    Nelson, R.T.

    1986-10-21

    This patent describes a dust collector comprising: (a) a housing having inlet means for receiving air to be cleaned; (b) a plurality of filter units within the housing; (c) a first centrifugal fan arranged for drawing air through the units for removing dust from the air; (d) a plurality of ducts each connected to a corresponding one of the units at one end and to the first fan at the other end to provide passages for air from the units to the first fan, the ducts through a portion of their length being arranged in side-by-side relationship; (e) a second centrifugal fan for providing reverse flow of air through the ducts to the units, the second fan providing a high volume of air at low pressure; (f) a transverse duct connected to the second fan and extending transversely of the portion of the plurality of ducts and adjacent thereto: (g) a plurality of openings providing communication between the transverse duct and each of the plurality of ducts; (i) rotatable means engaging the vanes for sequentially moving the vanes between the first and second positions.

  1. Observations of Saharan dust in the Caribbean and Implications for Regional Climate Variability

    NASA Technical Reports Server (NTRS)

    Remer, L.; Einaudi, Franco

    2001-01-01

    Massive quantities of dust aerosol, originating at source locations in the Saharan desert are frequently transported westward across the Atlantic. Saharan dust has been frequently identified at ground-based stations in South America, on Barbados, in Florida and in Texas. Recently, in July of 2000, the Puerto Rican Dust Experiment (PRiDE), consisting of researchers from the U.S. Navy, NASA, the University of Miami and the University of Puerto Rico joined together to study this important phenomenon. Numerical forecast models tracked each dust event as the dust left the African continent and transversed the Atlantic. Ground-based, ship-based, airborne and satellite sensors were used to characterize the physical and radiative properties of the dust aerosol. The dust plays an important role in terms of radiative forcing of regional climate. Satellite sensors such as NASA's EOS-MODIS aboard the Terra satellite will provide important continuing information on the dust aerosol and its climatic effects.

  2. Clear-Sky Closure Studies of Tropospheric Aerosol and Water Vapor During ACE-2 Using Airborne Sunphotometer, Airborne In-Situ, Space-Borne, and Ground-Based Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Collins, Donald R.; Gasso, Santiago; Oestroem, Elisabeth; Powell, Donna M.; Welton, Ellsworth J.; Durkee, Philip A.; Livingston, John M.; Russell, Philip B.; Flagan, Richard C.; Seinfeld, John H.; Hegg, Dean A.; Noone, Kevin J.; Voss, Kenneth J.; Gordon, Howard R.; Reagan, John A.; Spinhirne, James D.

    2000-01-01

    We report on clear-sky column closure experiments (CLEARCOLUMN) performed in the Canary Islands during the second Aerosol Characterization Experiment (ACE-2) in June/July 1997. We present CLEARCOLUMN results obtained by combining airborne sunphotometer and in-situ (a differential mobility analyzer, three optical particle counters, three nephelometers, and one absorption photometer) measurements taken aboard the Pelican aircraft, space-borne NOAA/AVHRR data and ground-based lidars. A wide range of aerosol types was encountered throughout the ACE-2 area, including background Atlantic marine, European pollution-derived, and (although less frequently than expected) African mineral dust. During the two days discussed here, vertical profiles flown in cloud free air masses revealed three distinctly different layers: a marine boundary layer (MBL) with varying pollution levels, an elevated dust layer, and a very clean layer between the MBL and the dust layer. Based on size-resolved composition information we have established an aerosol model that allows us to compute optical properties of the ambient aerosol using the optical particle counter results. In the dust, the agreement in layer AOD (lambda=380-1060 nm) is 3-8%. In the MBL there is a tendency for the in-situ results to be slightly lower than the sunphotometer measurements (10-17% at lambda=525 nm), but these differences are within the combined error bars of the measurements and computations. Aerosol size-distribudon closure based on in-situ size distributions and inverted sunphotometer extinction spectra has been achieved in the MBL (total surface area and volume agree within 0.2, and 7%, respectively) but not in the dust layer. The fact that the three nephelometers operated at three different relative humidities (RH) allowed to parameterize hygroscopic growth and to therefore estimate optical properties at ambient RH. The parameters derived for different aerosol types are themselves useful for the aerosol modeling

  3. Interstellar Dust: Contributed Papers

    NASA Technical Reports Server (NTRS)

    Tielens, Alexander G. G. M. (Editor); Allamandola, Louis J. (Editor)

    1989-01-01

    A coherent picture of the dust composition and its physical characteristics in the various phases of the interstellar medium was the central theme. Topics addressed included: dust in diffuse interstellar medium; overidentified infrared emission features; dust in dense clouds; dust in galaxies; optical properties of dust grains; interstellar dust models; interstellar dust and the solar system; dust formation and destruction; UV, visible, and IR observations of interstellar extinction; and quantum-statistical calculations of IR emission from highly vibrationally excited polycyclic aromatic hydrocarbon (PAH) molecules.

  4. How well do analyses capture dust-generating winds in the Sahara and Sahel?

    NASA Astrophysics Data System (ADS)

    Roberts, Alexander; Marsham, John; Knippertz, Peter; Parker, Douglas

    2016-04-01

    Airborne mineral dust is important for weather, climate and earth-system prediction. Uncertainty in winds, as well as the land-surface, are known to be key to model uncertainties for dust uplift. Recent research has shown that during the summer wet season in the Sahel strong winds generated by the cold outflow from organized convective systems are an important dust storm mechanism (so called haboobs), while over the inner Sahara nocturnal low-level jets forming on the pressure gradient around the heat low dominate. Together the Sahel and Sahara are the world's largest dust source. Until now there has been a severe shortage of data for evaluating models for this region. Here, we bring together new observations from the remote Sahara, made during the Fennec project, with Sahelian data from the African Monsoon Multidisciplinary Analysis (AMMA), to provide an unprecedented evaluation of dust-generating winds in the European Centre for Medium-Range Weather Forecasts ERA-Interim (ERA-I) reanalysis. Differences between observations and ERA-I are explored with specific attention to monsoon and non-monsoon influenced regions. The main results are: (1) High speed winds in instantaneous ERA-I grid-box mean winds are lacking compared to time-averaged wind speed observations; (2) agreement between ERA-I and observations is lower during the monsoon season, even in parts of the Sahara not directly affected by the monsoon; and (3) both the seasonal and diurnal variability is under-represented in ERA-I. ERA-I fails to capture the summertime maximum for monsoon-affected stations and seasonally, correlations between daily-mean ERA-I and observed winds vary from 0.8 to 0.4, with lower correlations for 3-hourly data. These differences demonstrate that the model used in the production of the ERA-I reanalysis is unable to represent some important dust uplift processes, especially during the monsoon season when moist convection plays a key role, and that the product is not sufficiently

  5. High sensitive airborne radioiodine monitor.

    PubMed

    Ogata, Yoshimune; Yamasaki, Tadashi; Hanafusa, Ryuji

    2013-11-01

    Airborne radioiodine monitoring includes a problem in that commercial radioactive gas monitors have inadequate sensitivity. To solve this problem, we designed a highly sensitive monitoring system. The higher counting efficiency and lower background made it possible to perform the low-level monitoring. The characteristics of the system were investigated using gaseous (125)I. The minimum detectable activity concentration was 1 × 10(-4)Bq cm(-3) for 1 min counting, which is one tenth of the legal limit for the radiation controlled areas in Japan. PMID:23602709

  6. Cyberinfrastructure for Airborne Sensor Webs

    NASA Technical Reports Server (NTRS)

    Freudinger, Lawrence C.

    2009-01-01

    Since 2004 the NASA Airborne Science Program has been prototyping and using infrastructure that enables researchers to interact with each other and with their instruments via network communications. This infrastructure uses satellite links and an evolving suite of applications and services that leverage open-source software. The use of these tools has increased near-real-time situational awareness during field operations, resulting in productivity improvements and the collection of better data. This paper describes the high-level system architecture and major components, with example highlights from the use of the infrastructure. The paper concludes with a discussion of ongoing efforts to transition to operational status.

  7. 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

  8. Cycling of Lead Through Soil, Air, and Household Dust in El Paso, Texas

    NASA Astrophysics Data System (ADS)

    Pingitore, N. E.; Clague, J.; Amaya, M. A.

    2008-12-01

    Elimination of leaded gasoline in the US is associated with a dramatic overall decrease in ambient lead in the environment and blood lead levels in our population. However, Pb is such a potent neurotoxin for children during the formative growth years that legislation for additional reduction of airborne lead levels is under consideration. X-ray absorption spectroscopy of a suite of samples of local (El Paso) soil, airborne particulate matter, and household dust reveals that lead humate is the dominant Pb species in these diverse environmental materials. Lead humate is a stable complex of Pb with the humus component of soil, a product of interaction between the humus and such introduced contaminant lead species as lead oxide, lead sulfate, etc. Because lead humate forms only in soil, we conclude that the source of the majority of the lead in El Paso's airborne particulate matter and household dust is local soils. Analysis of lead isotopes in selected samples is consistent with this conclusion. Re-entrainment of low-density (relative to most Pb species) humus soil particles is the apparent pathway from soil to air. Deposition of airborne particulate matter and pedal traction are the presumed mechanisms for transfer to household interiors. Reduction of airborne lead in El Paso by reducing input from its dominant local source may require extensive soil remediation, a tedious and expensive prospect. X-Ray absorption spectroscopy experiments were conducted at the Stanford Synchrotron Radiation Laboratory on beam lines 7-3, 10-2, and 11-2. Spectra were collected at the Pb L-III absorption edge in fluorescence mode using a 13-element or a 30-element Ge solid-state detector. This publication was made possible by grant numbers 1RO1-ES11367 and 1 S11 ES013339-04 from the National Institute of Environmental Health Sciences (NIEHS), NIH. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS, NIH. Partial

  9. Climate Response to Soil Dust Aerosols.

    NASA Astrophysics Data System (ADS)

    Miller, R. L.; Tegen, I.

    1998-12-01

    The effect of radiative forcing by soil dust aerosols upon climate is calculated. Two atmospheric GCM (AGCM) simulations are compared, one containing a prescribed seasonally varying concentration of dust aerosols, and the other omitting dust. Each simulation includes a mixed layer ocean model, which allows SST to change in response to the reduction in surface net radiation by dust. Dust aerosols reduce the surface net radiation both by absorbing and reflecting sunlight. For the optical properties of the dust particles assumed here, the reflection of sunlight is largely offset by the trapping of upwelling longwave radiation, so that the perturbation by dust to the net radiation gain at the top of the atmosphere is small in comparison to the surface reduction. Consequently, the radiative effect of soil dust aerosols is to redistribute heating from the surface to within the dust layer.Beneath the dust layer, surface temperature is reduced on the order of 1 K, typically in regions where deep convection is absent. In contrast, surface temperature remains unperturbed over the Arabian Sea during Northern Hemisphere (NH) summer, even though the dust concentration is highest in this region. It is suggested that the absence of cooling results from the negligible radiative forcing by dust at the top of the atmosphere, along with the frequent occurrence of deep convection, which ties the surface temperature to the unperturbed value at the emitting level.Where convection is absent, cooling at the surface occurs because radiative heating by dust reduces the rate of subsidence (and the corresponding mass exchange with the convecting region). Thus, the temperature contrast between these two regions must increase to maintain the original transport of energy, which is unperturbed by dust. It is suggested that cooling over the Arabian Sea during NH winter, despite the much smaller dust loading, is permitted by the absence of convection during this season. Thus, the change in surface

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

    PubMed Central

    2014-01-01

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

  11. Airborne iron across major urban centers in South Korea between 1991 and 2012.

    PubMed

    Kim, Ki-Hyun; Hong, Yoon-Jung; Szulejko, Jan E; Kang, Chang-Hee; Chambers, Scott; Feng, Xinbin; Deep, Akash; Kim, Yong-Hyun

    2016-04-15

    In this study, the distribution of airborne iron (Fe), one of the most abundant heavy metals in the Earth's crust was investigated to describe the basic features of i'ts pollution in various urban locations. The spatiotemporal distribution of Fe concentrations in seven major South Korean cities exhibited unique patterns to reflect differences as to Fe sources reflected in the relative enrichment in coastal relative to inland areas. In addition, the analysis of long-term trends of different metal species indicated that Fe levels maintained a fairly constant trend, while there had been a noticeable decline in concentrations of other metals (Cd, Cr, Cu, Mn, and Ni). The relative robustness of our correlation analysis was assessed by comparing (1) the Fe concentrations among cities, and (2) Fe with other metals at a given city. Fe concentrations were also partly explainable by the frequency of Asian dust events in most cities, with the observed spatial gradients in such relationships. PMID:26820934

  12. Retrospective exposure assessment to airborne asbestos among power industry workers

    PubMed Central

    2010-01-01

    Background A method of individually assessing former exposure to asbestos fibres is a precondition of risk-differentiated health surveillance. The main aims of our study were to assess former levels of airborne asbestos exposure in the power industry in Germany and to propose a basic strategy for health surveillance and the early detection of asbestos related diseases. Methods Between March 2002 and the end of 2006, we conducted a retrospective questionnaire based survey of occupational tasks and exposures with airborne asbestos fibres in a cohort of 8632 formerly asbestos exposed power industry workers. The data on exposure and occupation were entered into a specially designed computer programme, based on ambient monitoring of airborne asbestos fibre concentrations. The cumulative asbestos exposure was expressed as the product of the eight-hour time weighted average and the total duration of exposure in fibre years (fibres/cubic centimetre-years). Results Data of 7775 (90% of the total) participants working in installations for power generation, power distribution or gas supply could be evaluated. The power generation group (n = 5284) had a mean age of 56 years, were exposed for 20 years and had an average cumulative asbestos exposure of 42 fibre years. The occupational group of "metalworkers" (n = 1600) had the highest mean value of 79 fibre years. The corresponding results for the power distribution group (n = 2491) were a mean age of 45 years, a mean exposure duration of 12 years and an average cumulative asbestos exposure of only 2.5 fibre years. The gas supply workers (n = 512) had a mean age of 54 years and a mean duration of exposure of 15 years. Conclusions While the surveyed cohort as a whole was heavily exposed to asbestos dust, the power distribution group had a mean cumulative exposure of only 6% of that found in the power generation group. Based on the presented data, risk-differentiated disease surveillance focusing on metalworkers and electricians

  13. Steel dust in the New York City subway system as a source of manganese, chromium, and iron exposures for transit workers.

    PubMed

    Chillrud, Steven N; Grass, David; Ross, James M; Coulibaly, Drissa; Slavkovich, Vesna; Epstein, David; Sax, Sonja N; Pederson, Dee; Johnson, David; Spengler, John D; Kinney, Patrick L; Simpson, H James; Brandt-Rauf, Paul

    2005-03-01

    The United States Clean Air Act Amendments of 1990 reflected increasing concern about potential effects of low-level airborne metal exposure on a wide array of illnesses. Here we summarize results demonstrating that the New York City (NYC) subway system provides an important microenvironment for metal exposures for NYC commuters and subway workers and also describe an ongoing pilot study of NYC transit workers' exposure to steel dust. Results from the TEACH (Toxic Exposure Assessment, a Columbia and Harvard) study in 1999 of 41 high-school students strongly suggest that elevated levels of iron, manganese, and chromium in personal air samples were due to exposure to steel dust in the NYC subway. Airborne concentrations of these three metals associated with fine particulate matter were observed to be more than 100 times greater in the subway environment than in home indoor or outdoor settings in NYC. While there are currently no known health effects at the airborne levels observed in the subway system, the primary aim of the ongoing pilot study is to ascertain whether the levels of these metals in the subway air affect concentrations of these metals or related metabolites in the blood or urine of exposed transit workers, who due to their job activities could plausibly have appreciably higher exposures than typical commuters. The study design involves recruitment of 40 transit workers representing a large range in expected exposures to steel dust, the collection of personal air samples of fine particulate matter, and the collection of blood and urine samples from each monitored transit worker. PMID:15738337

  14. Byssinosis, Chronic Bronchitis, and Ventilatory Capacities in Workers Exposed to Soft Hemp Dust

    PubMed Central

    Valić, F.; Žuškin, E.; Walford, Joan; Keršić, W.; Pauković, R.

    1968-01-01

    A study was made of 93 women and 13 men employed in the spinning department of a factory in Yugoslavia processing soft hemp (Cannabis sativa). There were seven occupational groups, with average concentrations of total airborne hemp dust ranging from 2·9 mg./m.3 to more than 19·5 mg./m.3. Thirtyeight women and 11 men, employed in other departments of the factory with average total dust concentrations below 1·0 mg./m.3, were studied as controls. In the spinning department 40·6% of the workers had byssinosis and 15·1% had chronic bronchitis (defined as persistent cough and phlegm on most days for as much as three months each year during the last two years). None of the controls suffered from either disease. After adjustment for age, sitting height, and sex, the F.E.V.0·75 and F.V.C. measured at the beginning of the shift were used to assess the long-term effects of hemp dust on the ventilatory function of the lung. The age-adjusted ratio F.E.V.0·75/F.V.C. was also used. A comparison between the control group and the seven exposed groups showed no meaningful association between ventilatory function and present levels of dust exposure, but byssinotics with chronic bronchitis had a mean age-adjusted F.E.V.0·75/F.V.C. ratio significantly lower than that of workers with neither disease (P<0·05). Acute effects of hemp dust, measured by the change in F.E.V.0·75 and F.V.C. during the shift, were considerable. There were marked reductions in the mean F.E.V.0·75 and F.V.C. during the shift in all the occupational groups exposed to high concentrations of dust. Byssinotics with chronic bronchitis had a significantly greater mean decrease in F.E.V.0·75 during the shift than the byssinotics without chronic bronchitis, and the workers with neither disease (P<0·02). There is no doubt that the dust of Cannabis sativa hemp can cause byssinosis and at least temporary impairment of ventilatory function, varying in severity according to the level of dust exposure and the

  15. Relationship of airborne trimellitic anhydride concentrations to trimellitic anhydride--induced symptoms and immune responses

    SciTech Connect

    Bernstein, D.I.; Roach, D.E.; McGrath, K.G.; Larsen, R.S.; Zeiss, C.R.; Patterson, R.

    1983-12-01

    Eighteen workers exposed to trimellitic anhydride (TMA) powder were evaluated in 1979. Twelve of these workers were available for longitudinal study until 1982. Annual clinical evaluations and serum radioimmunoassays for total antibody binding and specific IgE binding to /sup 125/I-TM-HSA were performed. In 1979, five workers had antibody against TM-HSA. Of these, three workers were diagnosed with the late respiratory systemic syndrome (LRSS) and one worker with TMA-induced allergic rhinitis. The LRSS workers had significantly elevated total antibody binding of /sup 125/I-TM-HSA and the worker with rhinitis had significantly elevated specific IgE binding of /sup 125/I-TM-HSA per milliliter of serum. Although TMA handling was intermittent throughout the year, average airborne dust concentrations from 1974 to 1978 at job stations of the two heaviest TMA-exposed occupations, operator and assistant operator, were 2.1 and 0.82 mg/m3, respectively. After local exhaust ventilation had been improved, average airborne dust concentrations of TMA at the two latter job stations fell to levels of 0.03 and 0.01 mg/m3, respectively, in 1982. The decrease in TMA exposure coincided with a gradual fall in total antibody binding of /sup 125/I-TM-HSA per milliliter in 1982 and symptomatic improvement in the three individuals with the LRSS. The continuous low-level exposure of the worker with TMA rhinitis was sufficient to elicit a rise in specific IgE against TM-HSA from 1.1 ng of 125I-TM-HSA bound per milliliter in 1979 to 2.12 in 1982.

  16. Deposition Rates and Characterization of Arabian Mineral Dust

    NASA Astrophysics Data System (ADS)

    Puthan Purakkal, J.; Stenchikov, G. L.; Engelbrecht, J. P.

    2015-12-01

    Airborne mineral dust directly and indirectly impacts on global climate, continental and marine biochemistry, human and animal health, agriculture, equipment, and visibility. Annual global dust emissions are poorly known with estimates differing by a factor of at least two. Local dust emission and deposition rates are even less quantified. Dust deposition rate is a key parameter, which helps to constrain the modeled dust budget of the atmosphere. However, dust deposition remains poorly known, due to the limited number of reliable measurements. Simulations and satellite observations suggest that coastal dusts contribute substantially to the total deposition flux into the Red Sea. Starting December 2014, deposition samplers, both the "frisbee" type, and passive samplers for individual particle scanning electron microscopy were deployed at King Abdullah University of Science and Technology (KAUST), along the Red Sea in Saudi Arabia. Sampling periods of one month were adopted. The deposition rates range from 3 g m-2 month-1 for fair weather conditions to 23 g m-2 month-1 for high dust events. The X-ray diffraction (XRD) analyses of deposited dust samples show mineralogical compositions different from any of the parent soils, the former consisting mainly of gypsum, calcite, and smaller amounts of albite, montmorillonite, chlorite, quartz and biotite. The deposited dust samples on the other hand contain more gypsum and less quartz than the previously collected soil samples. This presentation discusses the results from XRD, chemical analysis and SEM-based individual particle analysis of the soils and the deposited dust samples. The monthly dust accumulation rates and their seasonal and spatial variability are compared with the regional model predictions. Data from this study provide an observational basis for validating the regional dust mass balance along the Arabian Red Sea coastal plain.

  17. Development of an electrostatic dust detector for tungsten dust

    NASA Astrophysics Data System (ADS)

    Starkey, D.; Hammond, K.; Roquemore, L.; Skinner, C. H.

    2012-10-01

    Next-step fusion reactors, such as ITER, are expected to have large quantities of dust that will present hazards that have yet to be encountered in current fusion devices. To manage the amount of dust within the reactors a real-time dust detector must be implemented to ensure that dust does not reach hazardous levels. An electrostatic device that accomplishes this has already been tested on NSTX and Tore Supra [1,2]. We will present modifications of this device to improve its ruggedness to withstand the conditions that will be present in ITER. The detector consists of two tungsten wires wrapped around a macor cylinder that are biased at 100-300 V. Incident dust causes a measurable transient short circuit. Initial results have demonstrated the detection of tungsten particles. We will also present a potential method of electrostatic cleaning of residual dust from the detector.[4pt] [1] C. H. Skinner et al., Rev. Sci. Instrum., 81, 10E102 (2010)[0pt] [2] H. Roche et al., Phys. Scr., T145, (2011).

  18. The Airborne Laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven E.

    2002-09-01

    The US Air Force Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the risk reduction approach being utilized to ensure program success.

  19. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Specifications and preliminary design of an Airborne Oceanographic Lidar (AOL) system, which is to be constructed for installation and used on a NASA Wallops Flight Center (WFC) C-54 research aircraft, are reported. The AOL system is to provide an airborne facility for use by various government agencies to demonstrate the utility and practicality of hardware of this type in the wide area collection of oceanographic data on an operational basis. System measurement and performance requirements are presented, followed by a description of the conceptual system approach and the considerations attendant to its development. System performance calculations are addressed, and the system specifications and preliminary design are presented and discussed.

  20. 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 identifi