Science.gov

Sample records for air concentration enrichment

  1. Barium concentration in cast roe deer antlers related to air pollution caused by burning of barium-enriched coals in southern Poland.

    PubMed

    Jabłońska, M; Kramarczyk, M; Smieja-Król, B; Janeczek, J

    2016-03-01

    Concentrations of Ba, Zn, Pb, Fe, and Mn were determined by atomic absorption spectroscopy in freshly cast antlers from male roe deer of different ages (2 to 4 years old and older than 4 years) collected in Balin near Chrzanów and in the vicinity of Żywiec, S Poland. Barium content ranged from 124 to 196 ppm (mean 165 ppm) in the Balin 12 samples and from 207 to 351 ppm (mean 287 ppm) in 3 antlers from Żywiec. The concentration of Ba was comparable to that of Zn (134-275 ppm, mean 169 ppm). Elevated concentrations of Ba in antlers most probably originated from direct uptake of airborne barite nanocrystals through the respiratory system and/or by digestion of barite-rich dust particles deposited on plants. Burning of Ba-enriched coals is regarded as the principal source of Ba in the investigated areas inhabited by roe deer. Increased concentrations of Ba in antlers from the Żywiec area compared to Balin reflect particularly high air pollution caused by coal-burning mostly for domestic purposes combined with an unfavorable topography that impedes efficient air circulation.

  2. Variable oxygen/nitrogen enriched intake air system for internal combustion engine applications

    DOEpatents

    Poola, Ramesh B.; Sekar, Ramanujam R.; Cole, Roger L.

    1997-01-01

    An air supply control system for selectively supplying ambient air, oxygen enriched air and nitrogen enriched air to an intake of an internal combustion engine includes an air mixing chamber that is in fluid communication with the air intake. At least a portion of the ambient air flowing to the mixing chamber is selectively diverted through a secondary path that includes a selectively permeable air separating membrane device due a differential pressure established across the air separating membrane. The permeable membrane device separates a portion of the nitrogen in the ambient air so that oxygen enriched air (permeate) and nitrogen enriched air (retentate) are produced. The oxygen enriched air and the nitrogen enriched air can be selectively supplied to the mixing chamber or expelled to atmosphere. Alternatively, a portion of the nitrogen enriched air can be supplied through another control valve to a monatomic-nitrogen plasma generator device so that atomic nitrogen produced from the nitrogen enriched air can be then injected into the exhaust of the engine. The oxygen enriched air or the nitrogen enriched air becomes mixed with the ambient air in the mixing chamber and then the mixed air is supplied to the intake of the engine. As a result, the air being supplied to the intake of the engine can be regulated with respect to the concentration of oxygen and/or nitrogen.

  3. Enrichment of ventilation air methane (VAM) with carbon fiber composites.

    PubMed

    Bae, Jun-Seok; Su, Shi; Yu, Xin Xiang

    2014-05-20

    Treatment of ventilation air methane (VAM) with cost-effective technologies has been an ongoing challenge due to its high volumetric flow rate with low and variable methane concentrations. In this work, honeycomb monolithic carbon fiber composites were developed and employed to capture VAM with a large-scale test unit at various conditions such as VAM concentration, ventilation air (VA) flow rate, temperature, and purging fluids. Regardless of inlet VAM concentrations, methane was captured at almost 100%. To regenerate the composites, the initial vacuum swing followed by combined temperature and vacuum swing adsorption (TVSA) was applied. It was found that initial vacuum swing is a control step for the final methane concentration having 5 or 11 times the VAM enrichment by one-step adsorption, which is, to our knowledge, the best performance achieved in VAM enrichment technologies worldwide. Five-time enriched VAM can be utilized as a principle fuel for lean burn turbine. Also, it can be further enriched by second step adsorption to more than 25% which then can be used for commercially available gas engines. In this way, the final product can be out of the methane explosive range (5-15%). PMID:24787090

  4. Air-conditioner filters enriching dust mites allergen

    PubMed Central

    Zhan, Xiaodong; Li, Chaopin; Xu, Haifeng; Xu, Pengfei; Zhu, Haibin; Diao, Jidong; Li, Na; Zhao, Beibei

    2015-01-01

    We detected the concentration of dust mites allergen (Der f1 & Der p1) in the air of different places before and after the starting of air-conditioners in Wuhu City, Anhui, China, and to discuss the relation between the dust mites allergen in air-conditioner filters and the asthma attack. The dust samples were collected from the air-conditioner filters in dining rooms, shopping malls, hotels and households respectively. Concentrations of dust mites major group allergen 1 (Der f 1, Der p1) were detected with enzyme linked immunosorbent assay (ELISA), and the dust mite immune activities were determined by dot-ELISA. The concentration of Der f1 in dining rooms, shopping malls, hotels and households was 1.52 μg/g, 1.24 μg/g, 1.31 μg/g and 1.46 μg/g respectively, and the concentration of Der p1 in above-mentioned places was 1.23 μg/g, 1.12 μg/g, 1.16 μg/g and 1.18 μg/g respectively. The concentration of Der f1 & Der p1 in air was higher after the air-conditioners starting one hours later, and the difference was significant (P<0.05, respectively). Additionally, dot-ELISA findings revealed that the allergen extracted from the dust was capable of reacting with IgE from the sera of asthma mice allergic to dust mites. The study concludes that air-conditioner filters can enrich dust mites major group allergen, and the allergens can induce asthma. The air-conditioner filters shall be cleaned or replaced regularly to prevent or reduce accumulation of the dust mites and its allergens. PMID:26064381

  5. Air-conditioner filters enriching dust mites allergen.

    PubMed

    Zhan, Xiaodong; Li, Chaopin; Xu, Haifeng; Xu, Pengfei; Zhu, Haibin; Diao, Jidong; Li, Na; Zhao, Beibei

    2015-01-01

    We detected the concentration of dust mites allergen (Der f1 & Der p1) in the air of different places before and after the starting of air-conditioners in Wuhu City, Anhui, China, and to discuss the relation between the dust mites allergen in air-conditioner filters and the asthma attack. The dust samples were collected from the air-conditioner filters in dining rooms, shopping malls, hotels and households respectively. Concentrations of dust mites major group allergen 1 (Der f 1, Der p1) were detected with enzyme linked immunosorbent assay (ELISA), and the dust mite immune activities were determined by dot-ELISA. The concentration of Der f1 in dining rooms, shopping malls, hotels and households was 1.52 μg/g, 1.24 μg/g, 1.31 μg/g and 1.46 μg/g respectively, and the concentration of Der p1 in above-mentioned places was 1.23 μg/g, 1.12 μg/g, 1.16 μg/g and 1.18 μg/g respectively. The concentration of Der f1 & Der p1 in air was higher after the air-conditioners starting one hours later, and the difference was significant (P<0.05, respectively). Additionally, dot-ELISA findings revealed that the allergen extracted from the dust was capable of reacting with IgE from the sera of asthma mice allergic to dust mites. The study concludes that air-conditioner filters can enrich dust mites major group allergen, and the allergens can induce asthma. The air-conditioner filters shall be cleaned or replaced regularly to prevent or reduce accumulation of the dust mites and its allergens. PMID:26064381

  6. Oxygen-enriched air for MHD power plants

    NASA Technical Reports Server (NTRS)

    Ebeling, R. W., Jr.; Cutting, J. C.; Burkhart, J. A.

    1979-01-01

    Cryogenic air-separation process cycle variations and compression schemes are examined. They are designed to minimize net system power required to supply pressurized, oxygen-enriched air to the combustor of an MHD power plant with a coal input of 2000 MWt. Power requirements and capital costs for oxygen production and enriched air compression for enrichment levels from 13 to 50% are determined. The results are presented as curves from which total compression power requirements can be estimated for any desired enrichment level at any delivery pressure. It is found that oxygen enrichment and recuperative heating of MHD combustor air to 1400 F yields near-term power plant efficiencies in excess of 45%. A minimum power compression system requires 167 MW to supply 330 lb of oxygen per second and costs roughly 100 million dollars. Preliminary studies show MHD/steam power plants to be competitive with plants using high-temperature air preheaters burning gas.

  7. Are δ13C values of n-alkanes affected by atmospheric CO2 concentrations? Results from a free-air CO2 enrichment (FACE) experiment.

    NASA Astrophysics Data System (ADS)

    Sandquist, D. R.; Williams, D. G.; Shuman, B. N.; Kim, S.; Chen, J.; Macdonald, C.

    2015-12-01

    Compound-specific carbon isotope (δ13C) analyses of leaf waxes (i.e., n-alkanes) can be linked to large-scale shifts in vegetation, such as dominant taxa, functional types, life-forms and photosynthetic pathways that are usually coupled with environmental changes in climate. However using these δ13C values to interpret finer-scale ecosystem properties, including climate attributes such as CO2 concentrations, is difficult owing to uncertainty in the magnitude of internal biosynthetic fractionations that determine the δ13C of waxes relative to that of bulk leaf material. We investigated the composition, abundance and δ13C of n-alkanes in the aboveground biomass of a C4 grass and a C3 grass exposed to experimentally controlled CO2 at ambient [490ppm] and elevated [630ppm] levels within natural grassland in Wyoming. The δ13C values of bulk tissues were predictably different based on the C3 and C4 photosynthetic pathways, but the difference between bulk tissue and n-alkanes (ɛlipid), for both C29 and C31, was consistently greater in the C4 grass. The magnitudes of these ɛlipid values were large (- 7‰ to -15‰) relative to those found in most other studies. CO2 concentration of the growing environment also had a significant effect on n-alkane δ13C values, with consistently higher values of ~ 2‰ under elevated CO2 found in both species and in both a wet and a dry year. These results underscore the importance of recognizing potential abiotic effects on leaf wax δ13C values, in addition to the biotic drivers their variation, when interpreting climate from leaf-wax biomarkers of terrestrial ecosystems.

  8. Reducing indoor air formaldehyde concentrations

    SciTech Connect

    Meyer, B.; Hermanns, K.

    1985-08-01

    Urea-formaldehyde resin bonded particle board, medium density fiberboard and plywood paneling are used as flooring, wall paneling, for cabinet work and in furniture, and are present in almost every office, home and public building. If large quantities of these products are used in poorly ventilated spaces, high manufacturing quality control is necessary to avoid problems of latent formaldehyde release. Indoor air formaldehyde concentrations depend on the nature of the product, the product surface to air volume (loading) factor, temperature, humidity, age and product emission rates. Standard test methods are now available for measuring product emission rates that make it possible to predict the performance of UF-bonded pressed wood materials if use conditions and environmental parameters are known. Recent modifications in adhesive and board manufacturing parameters have made it possible to reduce formaldehyde emission significantly, and UF-bonded wood products are now capable of meeting indoor air quality standard levels of 0.1 ppm under almost all customary loading conditions.

  9. A case study of air enrichment in rotary kiln incineration

    SciTech Connect

    Melo, G.F.; Lacava, P.T.; Carvalho, J.A. Jr.

    1998-07-01

    This paper presents a case study of air enrichment in an industrial rotary kiln type incineration unit. The study is based on mass and energy balances, considering the combustion reaction of a mixture composed by the residue and the auxiliary fuel with air enriched with oxygen. The steps are shown for the primary chamber (rotary kiln) and secondary chamber (afterburner). The residence times in the primary and secondary chamber are 2.0 and 3.2 sec, respectively. The pressure is atmospheric in both chambers. Based on constant chamber gas residence time and gas temperature, it is shown that the residue input rates can be increased by one order of magnitude as air is substituted by pure oxygen. As the residue consumption rate in the rotary kiln is also dependent on residue physical characteristics (mainly size), the study was also carried out for different percentages of oxygen in the oxidizer gas.

  10. Multi-stage combustion using nitrogen-enriched air

    DOEpatents

    Fischer, Larry E.; Anderson, Brian L.

    2004-09-14

    Multi-stage combustion technology combined with nitrogen-enriched air technology for controlling the combustion temperature and products to extend the maintenance and lifetime cycles of materials in contact with combustion products and to reduce pollutants while maintaining relatively high combustion and thermal cycle efficiencies. The first stage of combustion operates fuel rich where most of the heat of combustion is released by burning it with nitrogen-enriched air. Part of the energy in the combustion gases is used to perform work or to provide heat. The cooled combustion gases are reheated by additional stages of combustion until the last stage is at or near stoichiometric conditions. Additional energy is extracted from each stage to result in relatively high thermal cycle efficiency. The air is enriched with nitrogen using air separation technologies such as diffusion, permeable membrane, absorption, and cryogenics. The combustion method is applicable to many types of combustion equipment, including: boilers, burners, turbines, internal combustion engines, and many types of fuel including hydrogen and carbon-based fuels including methane and coal.

  11. INDOOR AIR CONCENTRATION UNIT CONVERSIONS

    EPA Science Inventory

    Migration of volatile chemicals from the subsurface into overlying buildings is called vapor intrusion (VI). Volatile organic chemicals in contaminated soils or groundwater can emit vapors, which can migrate through subsurface soils and may enter the indoor air of overlying buil...

  12. Air liquefaction and enrichment system propulsion in reusable launch vehicles

    SciTech Connect

    Bond, W.H.; Yi, A.C.

    1994-07-01

    A concept is shown for a fully reusable, Earth-to-orbit launch vehicle with horizontal takeoff and landing, employing an air-turborocket for low speed and a rocket for high-speed acceleration, both using liquid hydrogen for fuel. The turborocket employs a modified liquid air cycle to supply the oxidizer. The rocket uses 90% pure liquid oxygen as its oxidizer that is collected from the atmosphere, separated, and stored during operation of the turborocket from about Mach 2 to 5 or 6. The takeoff weight and the thrust required at takeoff are markedly reduced by collecting the rocket oxidizer in-flight. This article shows an approach and the corresponding technology needs for using air liquefaction and enrichment system propulsion in a single-stage-to-orbit (SSTO) vehicle. Reducing the trajectory altitude at the end of collection reduces the wing area and increases payload. The use of state-of-the-art materials, such as graphite polyimide, in a direct substitution for aluminum or aluminum-lithium alloy, is critical to meet the structure weight objective for SSTO. Configurations that utilize `waverider` aerodynamics show great promise to reduce the vehicle weight. 5 refs.

  13. The balance model of oxygen enrichment of atmospheric air

    NASA Astrophysics Data System (ADS)

    Popov, Alexander

    2013-04-01

    The study of turnover of carbon and oxygen is an important line of scientific investigation. This line takes on special significance in conditions of soil degradation, which leads to the excess content of carbon dioxide and, as result, decrease of oxygen in the atmosphere. The aim of this article is a statement the balance model of oxygen enrichment of atmospheric air (ratio O/C) depending on consumption and assimilation by plants of dissolved organic matter (DOM) and the value of the oxidation-reduction potential (Eh). Basis of model was the following: green vascular plants are facultative heterotrophic organisms with symbiotic digestion and nutrition. According to the trophology viewpoint, the plant consumption of organic compounds broadens greatly a notion about the plant nutrition and ways of its regulation. In particular, beside the main known cycle of carbon: plant - litter - humus - carbon dioxide - plant, there is the second carbon cycle (turnover of organic compounds): plant - litter - humus - DOM - plant. The biogeochemical meaning of consumption of organic compounds by plants is that plants build the structural and functional blocks of biological macromolecules in their bodies. It provides receiving of a certain "energy payoff" by plants, which leads to increase of plant biomass by both an inclusion of allochthonous organic molecules in plant tissues, and positive effect of organic compounds on plant metabolic processes. One more of powerful ecological consequence of a heterotrophic nutrition of green plants is oxygen enrichment of atmospheric air. As the organic molecules in the second biological cycle of carbon are built in plants without considerable chemical change, the atmospheric air is enriched on that amount of oxygen, which would be required on oxidation of the organic molecules absorbed by plants, in result. It was accepted that: plant-soil system was climax, the plant community was grassy, initial contents of carbon in phytomass was accepted

  14. Observations on using inside air concentrations as a predictor of outside air concentrations

    SciTech Connect

    Hawkley, Gavin; Whicker, Jeffrey; Harris, Jason

    2015-04-01

    Here, excavations of radiological material were performed within confined structures with known operational parameters, such as a filtered exhaust system with known filtration efficiency. Given the known efficiency, the assumption could be made that the air concentrations of radioactivity measured outside the structure would be proportional to the air concentrations measured inside the structure. To investigate this assumption, the inside concentration data was compared with the outside concentration data. The correlation of the data suggested that the inside concentrations were not a good predictor of the outside concentrations. This poor correlation was deemed to be a result of operational unknowns within the structures.

  15. Observations on using inside air concentrations as a predictor of outside air concentrations

    DOE PAGES

    Hawkley, Gavin; Whicker, Jeffrey; Harris, Jason

    2015-04-01

    Here, excavations of radiological material were performed within confined structures with known operational parameters, such as a filtered exhaust system with known filtration efficiency. Given the known efficiency, the assumption could be made that the air concentrations of radioactivity measured outside the structure would be proportional to the air concentrations measured inside the structure. To investigate this assumption, the inside concentration data was compared with the outside concentration data. The correlation of the data suggested that the inside concentrations were not a good predictor of the outside concentrations. This poor correlation was deemed to be a result of operational unknownsmore » within the structures.« less

  16. Scavenging ratios based on inflow air concentrations

    SciTech Connect

    Davis, W.E.; Dana, M.T.; Lee, R.N.; Slinn, W.G.N.; Thorp, J.M.

    1991-07-01

    Scavenging ratios were calculated from field measurements made during April 1985. Event precipitation samples were collected at the surface, but air chemistry measurements in the air mass feeding the precipitation were made from an aircraft. In contrast, ratios calculated in previous studies have used air concentration and precipitation chemistry data from only surface measurements. Average scavenging ratios were calculated for SO{sub 4}{sup 2{minus}}, NO{sub 3}{sup {minus}}, NH{sub 4}{sup +}, total sulfate, total nitrate, and total ammonium for 5 events; the geometric mean of these scavenging ratios were 8.5 {times} 10{sup 5}, 5.6 {times} 10{sup 6}, 4.3 {times} 10{sup 5}, 3.4 {times} 10{sup 5}, 2.4 {times} 10{sup 6}, and 9.7 {times} 10{sup 4}, respectively. These means are similar to but less variable than previous ratios formed using only surface data.

  17. The method for on-site determination of trace concentrations of methyl mercaptan and dimethyl sulfide in air using a mobile mass spectrometer with atmospheric pressure chemical ionization, combined with a fast enrichment/separation system.

    PubMed

    Kudryavtsev, Andrey S; Makas, Alexey L; Troshkov, Mikhail L; Grachev, Mikhail А; Pod'yachev, Sergey P

    2014-06-01

    A method for fast simultaneous on-site determination of methyl mercaptan and dimethyl sulfide in air was developed. The target compounds were actively collected on silica gel, followed by direct flash thermal desorption, fast separation on a short chromatographic column and detection by means of mass spectrometer with atmospheric pressure chemical ionization. During the sampling of ambient air, water vapor was removed with a Nafion selective membrane. A compact mass spectrometer prototype, which was designed earlier at Trofimuk Institute of Petroleum Geology and Geophysics, was used. The minimization of gas load of the atmospheric pressure ion source allowed reducing the power requirements and size of the vacuum system and increasing its ruggedness. The measurement cycle is about 3 min. Detection limits in a 0.6 L sample are 1 ppb for methyl mercaptan and 0.2 ppb for dimethyl sulfide.

  18. Experimental and kinetic modeling of oxygen-enriched air combustion of municipal solid waste.

    PubMed

    Liu, Guo Hui; Ma, Xiao Qian; Yu, Zhaosheng

    2009-02-01

    The characteristics of oxygen-enriched air combustion of raw municipal solid waste (MSW) were studied by thermogravimetric analysis. Experiments on oxidative pyrolysis of MSW were carried out under different atmospheres (N(2), N(2):O(2)=7:3, N(2):O(2)=5:5, N(2):O(2)=4:6, and N(2):O(2)=2:8) at 30 degrees C/min. Two distinct peaks of weight loss were obtained according to the derivative thermogravimetric curves; one of them is centered on 305 degrees C with about 40% weight loss, and the second is centered on 420 degrees C with about 20% weight loss. Effects of oxygen concentration on the decomposition process and char combustion were analyzed, and then the process of oxygen-enriched air combustion of MSW was divided into four steps. Kinetic parameters were observed by direct non-linear regressions. According to the obtained data, the apparent activation energy and reaction order decreases along with the combustion process, while that of char combustion increases as oxygen concentration increases. PMID:18691862

  19. Free Air CO2 Enrichment (FACE) Data from the Duke Forest FACE Facility

    DOE Data Explorer

    DOE has conducted trace gas enrichment experiments since the mid 1990s. The FACE Data Management System is a central repository and archive for Free-Air Carbon Dioxide Enrichment (FACE) data, as well as for the related open-top chamber (OTC) experiments. FACE Data Management System is located at DOEÆs Carbon Dioxide Information Analysis Center (CDIAC). While the data from the various FACE sites, each one a unique user facility, are centralized at CDIAC, each of the FACE sites presents its own view of its activities and information. For that reason, DOE Data Explorer users are advised to see both the central repository at http://public.ornl.gov/face/index.shtml and the individual home pages of each site. The Duke University FACE website actually presents information on several FACE experiments. The Forest-Atmosphere Carbon Transfer and Storage (FACTS-I) facility is located in the Blackwood Division of the Duke Forest. It consists of four free-air CO2 enrichment (FACE) plots that provide elevated atmospheric CO2 concentration and four plots that provide ambient CO2 control. The system has been in operation since June, 1994 in the prototype plot, and since August, 1996 in the three additional plots. The prototype plot and its reference were halved with a barrier inserted in the soil in 1998 to conduct, together with five additional plot pairs, CO2 X soil nutrient enrichment experiments. The rest of the plots were partitioned in early 2005 and incorporated into the CO2 X nutrient experiment. To increase statistical power, four additional ambient plots were established in January, 2005, halved, and one half of each fertilized. [copied from http://face.env.duke.edu/description.cfm] The Duke FACE home page makes information available from both completed and ongoing projects, provides a searchable database of publications and presentations, and data, images, and links to related websites.

  20. Assessing model sensitivity and uncertainty across multiple Free-Air CO2 Enrichment experiments.

    NASA Astrophysics Data System (ADS)

    Cowdery, E.; Dietze, M.

    2015-12-01

    As atmospheric levels of carbon dioxide levels continue to increase, it is critical that terrestrial ecosystem models can accurately predict ecological responses to the changing environment. Current predictions of net primary productivity (NPP) in response to elevated atmospheric CO2 concentrations are highly variable and contain a considerable amount of uncertainty. It is necessary that we understand which factors are driving this uncertainty. The Free-Air CO2 Enrichment (FACE) experiments have equipped us with a rich data source that can be used to calibrate and validate these model predictions. To identify and evaluate the assumptions causing inter-model differences we performed model sensitivity and uncertainty analysis across ambient and elevated CO2 treatments using the Data Assimilation Linked Ecosystem Carbon (DALEC) model and the Ecosystem Demography Model (ED2), two process-based models ranging from low to high complexity respectively. These modeled process responses were compared to experimental data from the Kennedy Space Center Open Top Chamber Experiment, the Nevada Desert Free Air CO2 Enrichment Facility, the Rhinelander FACE experiment, the Wyoming Prairie Heating and CO2 Enrichment Experiment, the Duke Forest Face experiment and the Oak Ridge Experiment on CO2 Enrichment. By leveraging data access proxy and data tilling services provided by the BrownDog data curation project alongside analysis modules available in the Predictive Ecosystem Analyzer (PEcAn), we produced automated, repeatable benchmarking workflows that are generalized to incorporate different sites and ecological models. Combining the observed patterns of uncertainty between the two models with results of the recent FACE-model data synthesis project (FACE-MDS) can help identify which processes need further study and additional data constraints. These findings can be used to inform future experimental design and in turn can provide informative starting point for data assimilation.

  1. Assessing the potential for dimethylsulfide enrichment at the sea surface and its influence on air-sea flux

    NASA Astrophysics Data System (ADS)

    Walker, Carolyn F.; Harvey, Mike J.; Smith, Murray J.; Bell, Thomas G.; Saltzman, Eric S.; Marriner, Andrew S.; McGregor, John A.; Law, Cliff S.

    2016-09-01

    The flux of dimethylsulfide (DMS) to the atmosphere is generally inferred using water sampled at or below 2 m depth, thereby excluding any concentration anomalies at the air-sea interface. Two independent techniques were used to assess the potential for near-surface DMS enrichment to influence DMS emissions and also identify the factors influencing enrichment. DMS measurements in productive frontal waters over the Chatham Rise, east of New Zealand, did not identify any significant gradients between 0.01 and 6 m in sub-surface seawater, whereas DMS enrichment in the sea-surface microlayer was variable, with a mean enrichment factor (EF; the concentration ratio between DMS in the sea-surface microlayer and in sub-surface water) of 1.7. Physical and biological factors influenced sea-surface microlayer DMS concentration, with high enrichment (EF > 1.3) only recorded in a dinoflagellate-dominated bloom, and associated with low to medium wind speeds and near-surface temperature gradients. On occasion, high DMS enrichment preceded periods when the air-sea DMS flux, measured by eddy covariance, exceeded the flux calculated using National Oceanic and Atmospheric Administration (NOAA) Coupled-Ocean Atmospheric Response Experiment (COARE) parameterized gas transfer velocities and measured sub-surface seawater DMS concentrations. The results of these two independent approaches suggest that air-sea emissions may be influenced by near-surface DMS production under certain conditions, and highlight the need for further study to constrain the magnitude and mechanisms of DMS production in the sea-surface microlayer.

  2. Assessing the influence of CH4 concentration during culture enrichment on the biodegradation kinetics and population structure.

    PubMed

    López, Juan C; Quijano, Guillermo; Pérez, Rebeca; Muñoz, Raúl

    2014-12-15

    Methanotrophic communities were enriched in three stirred tank reactors continuously supplied with CH4-laden air at 20, 2 and 0.2 gCH4 m(-3) in order to evaluate the influence of CH4 concentration on the biodegradation kinetics, population structure and potential polyhydroxyalkanoate production under sequential nitrogen limitations. The population structure of the enriched cultures, dominated by type I methanotrophs, was influenced by CH4 concentration. No significant correlation between CH4 concentration and the maximum specific degradation rate (qmax) or the half-saturation constant (KS) was recorded, microorganisms enriched at 2 gCH4 m(-3) presenting the highest qmax and those enriched at 20 and 0.2 gCH4 m(-3) exhibiting the lowest KS. Maximum polyhydroxybutyrate (PHB) contents of 1.0% and 12.6% (w/w) were achieved at 20 and 2 g CH4 m(-3), respectively. Polyhydroxyvalerate (PHV) was also detected at PHV:PHB ratios of up to 12:1 and 4:1 in the communities enriched at 20 and 0.2 gCH4 m(-3), respectively.

  3. The effects of oxygen-enriched intake air on FFV exhaust emissions using M85

    SciTech Connect

    Poola, R.B.; Sekar, R.; Ng, H.K.; Baudino, J.H.; Colucci, C.P.

    1996-05-01

    This paper presents results of emission tests of a flexible fuel vehicle (FFV) powered by an SI engine, fueled by M85 (methanol), and supplied with oxygen-enriched intake air containing 21, 23, and 25 vol% O2. Engine-out total hydrocarbons (THCs) and unburned methanol were considerably reduced in the entire FTP cycle when the O2 content of the intake air was either 23 or 25%. However, CO emissions did not vary much, and NOx emissions were higher. HCHO emissions were reduced by 53% in bag 1, 84% in bag 2, and 59% in bag 3 of the FTP cycle with 25% oxygen-enriched intake air. During cold-phase FTP,reductions of 42% in THCs, 40% in unburned methanol, 60% in nonmethane hydrocarbons, and 45% in nonmethane organic gases (NMOGs) were observed with 25% enriched air; NO{sub x} emissions increased by 78%. Converter-out emissions were also reduced with enriched air but to a lesser degree. FFVs operating on M85 that use 25% enriched air during only the initial 127 s of cold-phase FTP or that use 23 or 25% enriched air during only cold-phase FTP can meet the reactivity-adjusted NMOG, CO, NO{sub x}, and HCHO emission standards of the transitional low-emission vehicle.

  4. Premixed CH4/O2-enriched air combustion: Identification of thermal, chemical and aerodynamic effects

    NASA Astrophysics Data System (ADS)

    Most, J.-M.; Dahikar, S.; Pal, S.; Claverie, A.; Denis, D.; Pillier, L.; de Persis, S.

    2012-11-01

    This work contributes to the evaluation of a new innovative process focused on the reduction of the cost of a post-combustion capture of CO2 in a Carbon Capture and Storage system (CCS). The process based on the separation of dried fumes composed mainly by CO2 and N2 by using membranes, which should lead to a lower energetic separation cost than amines. But the membranes become efficient if the upstream CO2 concentration is higher than 30% at their entrance that requires enriching the oxidizer flow by O2. To maintain the exhaust temperature compatible with materials thermal resistance, the reactants are diluted by a recirculation of a part of the flue gases (like N2/O2/CO2). But, the chemical kinetic, the energetic efficiencies, the radiation transfer, the transport and thermal properties of the flow can be affected by CO2. The objective of this work will be to identify the behaviour of the combustion of premixed CH4/O2-enriched air, both diluted in N2 and CO2 and to determine the combustion parameters. This allows to recover the CH4/air conditions in terms of CO2 concentration in reactants, O2 excess, dilution rate, temperature of the reactants, etc. Experiments are performed on the laminar premixed flame using counterflow burner. To characterize the combustion behaviour, the flammability limits are determined and flame thickness and position are measured from PLIF-OH diagnostic. Further, CHEMKIN simulations are performed to check the validity of the GRI3.0 chemical kinetic mechanism for premixed CH4/air synthetic combustion and identify the leading phenomena.

  5. Free Air CO2 Enrichment (FACE) Research Data from the Aspen FACE Experiment (FACTS II)

    DOE Data Explorer

    DOE has conducted trace gas enrichment experiments since the mid 1990s. The FACE Data Management System is a central repository and archive for Free-Air Carbon Dioxide Enrichment (FACE) data, as well as for the related open-top chamber (OTC) experiments. FACE Data Management System is located at DOE’s Carbon Dioxide Information Analysis Center (CDIAC). While the data from the various FACE sites, each one a unique user facility, are centralized at CDIAC, each of the FACE sites presents its own view of its activities and information. For that reason, DOE Data Explorer users are advised to see both the central repository at http://public.ornl.gov/face/index.shtml and the individual home pages of each site. FACTS II, the Aspen FACE Experiment is a multidisciplinary study to assess the effects of increasing tropospheric ozone and carbon dioxide levels on the structure and function of northern forest ecosystems. The Aspen FACE facility is located at the Harshaw Experimental Forest near Rhinelander, Wisconsin. It consists of twelve 30m rings in which the concentrations of carbon dioxide and tropospheric ozone can be controlled. The design provides the ability to assess the effects of these gasses alone, and in combination, on many ecosystem attributes, including growth, leaf development, root characteristics, and soil carbon. Each ring consists of a series of vertical ventpipes which disperse carbon dioxide, ozone or normal air into the center of the ring. This computer controlled system uses signal feedback technology to adjust gas release each second in order to maintain a stable, elevated concentration of carbon dioxide and/or ozone throughout the experimental plot. Because there is no confinement, there is no significant change in the natural, ambient environment other than elevating these trace gas concentrations. [copied from http://aspenface.mtu.edu/index.html] Ring maps, lists of publications, data from the experiments, newsletters, protocol and performance

  6. Free Air CO2 Enrichment (FACE) Research Data from the Nevada Desert FACE Facility (NDFF)

    DOE Data Explorer

    DOE has conducted trace gas enrichment experiments since the mid 1990s. The FACE Data Management System is a central repository and archive for Free-Air Carbon Dioxide Enrichment (FACE) data, as well as for the related open-top chamber (OTC) experiments. FACE Data Management System is located at the Carbon Dioxide Information Analysis Center (CDIAC). While the data from the various FACE sites, each one a unique user facility, are centralized at CDIAC, each of the FACE sites presents its own view of its activities and information. For that reason, DOE Data Explorer users are advised to see both the central repository at http://public.ornl.gov/face/index.shtml and the individual home pages of each site. NDFF whole-ecosystem manipulation is a flagship experiment of the Terrestrial Carbon Process (TCP) research program of the US Dept. of Energy. It is also a core project of the International Geosphere-Biosphere Program (IGBP) and a contribution to the US Global Change Research Program. The NDFF was developed in conjunction with the National Science Foundation (NSF) and DOE-EPSCoR programs. FACE (Free-Air-Carbon dioxide-Enrichment) technology allows researchers to elevate the carbon dioxide level in large study plots while minimizing ecosystem disturbance. At the NDFF the concentration of CO2 was elevated by 50 percent above the present atmospheric levels in three plots in the Mojave Desert ecosystem, while six other plots remained at the current level. This experimental design provided a large area in which integrated teams of scientists could describe and quantify processes regulating carbon, nutrient, and water balances in desert ecosystems.

  7. Modeling forest C and N allocation responses to free-air CO2 enrichment

    NASA Astrophysics Data System (ADS)

    Luus, Kristina; De Kauwe, Martin; Walker, Anthony; Werner, Christian; Iversen, Colleen; McCarthy, Heather; Medlyn, Belinda; Norby, Richard; Oren, Ram; Zak, Donald; Zaehle, Sönke

    2015-04-01

    Vegetation allocation patterns and soil-vegetation partitioning of C and N are predicted to change in response to rising atmospheric concentrations of CO2. These allocation responses to rising CO2 have been examined at the ecosystem level through through free-air CO2 enrichment (FACE) experiments, and their global implications for the timing of progressive N limitation (PNL) and C sequestration have been predicted for ~100 years using a variety of ecosystem models. However, recent FACE model-data syntheses studies [1,2,3] have indicated that ecosystem models do not capture the 5-10 year site-level ecosystem allocation responses to elevated CO2. This may be due in part to the missing representation of the rhizosphere interactions between plants and soil biota in models. Ecosystem allocation of C and N is altered by interactions between soil and vegetation through the priming effect: as plant N availability diminishes, plants respond physiologically by altering their tissue allocation strategies so as to increase rates of root growth and rhizodeposition. In response, either soil organic material begins to accumulate, which hastens the onset of PNL, or soil microbes start to decompose C more rapidly, resulting in increased N availability for plant uptake, which delays PNL. In this study, a straightforward approach for representing rhizosphere interactions in ecosystem models was developed through which C and N allocation to roots and rhizodeposition responds dynamically to elevated CO2 conditions, modifying soil decomposition rates without pre-specification of the direction in which soil C and N accumulation should shift in response to elevated CO2. This approach was implemented in a variety of ecosystem models ranging from stand (G'DAY), to land surface (CLM 4.5, O-CN), to dynamic global vegetation (LPJ-GUESS) models. Comparisons against data from three forest FACE sites (Duke, Oak Ridge & Rhinelander) indicated that representing rhizosphere interactions allowed

  8. Study of using oxygen-enriched combustion air for locomotive diesel engines

    SciTech Connect

    Poola, R.B.; Sekar, R.; Assanis, D.N.; Cataldi, G.R.

    1996-12-31

    A thermodynamic simulation is used to study the effects of oxygen-enriched intake air on the performance and nitrogen oxide (NO) emissions of a locomotive diesel engine. The parasitic power of the air separation membrane required to supply the oxygen-enriched air is also estimated. For a given constraint on peak cylinder pressure, the gross and net power output of an engine operating under different levels of oxygen enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in an increase in net engine power of approximately 13% when intake air with an oxygen content of 28% by volume is used and fuel injection timing is retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure can improve power by only 4%. If part of the significantly higher exhaust enthalpies available as a result of oxygen enrichment are recovered, the power requirements of the air separator membrane can be met, resulting in substantial net power improvements. Oxygen enrichment with its attendant higher combustion temperatures, reduces emissions of particulates and visible smoke but increases NO emissions (by up to three times at 26% oxygen content). Therefore, exhaust gas after-treatment and heat recovery would be required if the full potential of oxygen enrichment for improving the performance of locomotive diesel engines is to be realized.

  9. Study of using oxygen-enriched combustion air for locomotive diesel engines

    SciTech Connect

    Poola, R.B.; Sekar, R.; Assanis, D.N.; Cataldi, G.R.

    1996-10-01

    A thermodynamic simulation is used to study effects of O2-enriched intake air on performance and NO emissions of a locomotive diesel engine. Parasitic power of the air separation membrane required to supply the O2-enriched air is also estimated. For a given constraint on peak cylinder pressure, gross and net power output of an engine operating under different levels of O2 enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in 13% increase in net engine power when intake air with 28 vol% O2 is used and fuel injection timing retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure can result in only 4% improvement in power. If part of the higher exhaust enthalpies from the O2 enrichment is recovered, the power requirements of the air separator membrane can be met. O2 enrichment with its higher combustion temperatures reduces emissions of particulates and visible smoke but increases NO emissions (by up to 3 times at 26% O2 content). Therefore, exhaust gas after-treatment and heat recovery would be required if the full potential of O2 enrichment for improving the performance of locomotive diesel engines is to be realized.

  10. Long-memory property in air pollutant concentrations

    NASA Astrophysics Data System (ADS)

    Chelani, Asha

    2016-05-01

    In the present paper, long-memory in air pollutant concentrations is reviewed and outcome of the past studies is analyzed to provide the possible mechanism behind temporal evolution of air pollutant concentrations. It is observed that almost all the studies show air pollutant concentrations over time possess persistence up to a certain limit. Self-organized criticality of air pollution, multiplicative process of pollutant concentrations, and uniformity in emission sources leading to self-organized criticality are few of the phenomena behind the persistent property of air pollutant concentrations. The self-organized criticality of air pollution is linked to atmosphere's self-cleansing mechanism. This demonstrates that inspite of increasing anthropogenic emissions, self-organized criticality of air pollution is sustained and has low influence of human interventions. In the future, this property may, however, be perturbed due to continuous air pollution emissions, which may influence the accuracy in predictions.

  11. Method and apparatus for reducing cold-phase emissions by utilizing oxygen-enriched intake air

    DOEpatents

    Poola, Ramesh B.; Sekar, Ramanujam R.; Stork, Kevin C.

    1997-01-01

    An oxygen-enriched air intake control system for an internal combustion engine includes air directing apparatus to control the air flow into the intake of the engine. During normal operation of the engine, ambient air flowing from an air filter of the engine flows through the air directing apparatus into the intake of the engine. In order to decrease the amount of carbon monoxide (CO) and hydrocarbon (HC) emissions that tend to be produced by the engine during a short period of time after the engine is started, the air directing apparatus diverts for a short period of time following the start up of the engine at least a portion of the ambient air from the air filter through a secondary path. The secondary path includes a selectively permeable membrane through which the diverted portion of the ambient air flows. The selectively permeable membrane separates nitrogen and oxygen from the diverted air so that oxygen enriched air containing from about 23% to 25% oxygen by volume is supplied to the intake of the engine.

  12. Concentrated Solar Air Conditioning for Buildings Project

    NASA Technical Reports Server (NTRS)

    McLaughlin, Rusty

    2010-01-01

    This slide presentation reviews project to implement the use of solar power to provide air conditioning for NASA buildings. Included is an overall conceptual schematic, and an diagram of the plumbing and instrumentation for the project. The use of solar power to power air conditioning in buildings, particularly in the Southwest, could save a significant amount of money. DOD studies have concluded that air conditioning accounts for 30-60% of total energy expenditures.

  13. Heat-tolerant rice cultivars retain grain appearance quality under free-air CO2 enrichment

    PubMed Central

    2014-01-01

    Background Heat-tolerant rice cultivars have been developed as a countermeasure to poor grain appearance quality under high temperatures. Recent studies showed that elevated CO2 concentrations (E-[CO2]) also reduce grain quality. To determine whether heat-tolerant cultivars also tolerate E-[CO2], we conducted a free-air CO2 enrichment (FACE) experiment with 12 rice cultivars differing in heat tolerance. Results The percentage of undamaged grains of five standard cultivars (Akitakomachi, Kinuhikari, Koshihikari, Matsuribare, Nipponbare) averaged 61.7% in the ambient [CO2] (AMB) plot and 51.7% in the FACE plot, whereas that of heat-tolerant cultivars (Eminokizuna, Wa2398, Kanto 257, Toyama 80, Mineharuka, Kanto 259, Saikai 290) averaged 73.5% in AMB and 71.3% in FACE. This resulted in a significant [CO2] by cultivar interaction. The percentage of white-base or white-back grains increased from 8.4% in AMB to 17.1% in FACE in the sensitive cultivars, but from only 2.1% in AMB to only 4.4% in FACE in the heat-tolerant cultivars. Conclusion Heat-tolerant cultivars retained their grain appearance quality at E-[CO2] under present air temperatures. Further improvements in appearance quality under present conditions will be needed to achieve improvements under E-[CO2], because E-[CO2] will likely lower the threshold temperature for heat stress. PMID:24920972

  14. 40 CFR Appendix IV to Part 266 - Reference Air Concentrations*

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Reference Air Concentrations* IV Appendix IV to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... MANAGEMENT FACILITIES Pt. 266, App. IV Appendix IV to Part 266—Reference Air Concentrations* Constituent...

  15. Ecological Lessons from Free-Air CO2 Enrichment (FACE) Experiments

    SciTech Connect

    Norby, Richard J; Zak, Donald R

    2011-01-01

    Free-air CO{sub 2} enrichment (FACE) experiments have provided novel insights into the ecological mechanisms controlling the cycling and storage of carbon in terrestrial ecosystems and contribute to our ability to project how ecosystems respond to increasing CO{sub 2} in the Earth's atmosphere. Important lessons emerge by evaluating a set of hypotheses that initially guided the design and longevity of forested FACE experiments. Net primary productivity is increased by elevated CO{sub 2}, but the response can diminish over time. Carbon accumulation is driven by the distribution of carbon among plant and soil components with differing turnover rates and by interactions between the carbon and nitrogen cycles. Plant community structure may change, but elevated CO{sub 2} has only minor effects on microbial community structure. FACE results provide a strong foundation for next-generation experiments in unexplored ecosystems and inform coupled climate-biogeochemical models of the ecological mechanisms controlling ecosystem response to the rising atmospheric CO{sub 2} concentration.

  16. Stem respiration of Populus species in the third year of free-air CO2 enrichment.

    PubMed

    Gielen, Birgit; Scarascia-Mugnozza, Giuseppe; Ceulemans, Reinhart

    2003-04-01

    Carbon cycling in ecosystems, and especially in forests, is intensively studied to predict the effects of global climate change, and the role which forests may play in 'changing climate change'. One of the questions is whether the carbon balance of forests will be affected by increasing atmospheric CO2 concentrations. Regarding this question, effects of elevated [CO2] on woody-tissue respiration have frequently been neglected. Stem respiration of three Populus species (P. alba L. (Clone 2AS-11), P. nigra L. (Clone Jean Pourtet), and P. x euramericana (Clone I-214)) was measured in a managed, high-density forest plantation exposed to free-air CO2 enrichment (POPFACE). During the period of measurements, in May of the third year, stem respiration rates were not affected by the FACE treatment. Moreover, FACE did not influence the relationships between respiration rate and both stem temperature and relative growth rate. The results were supported by the reported absence of a FACE-effect on growth and stem wood density.

  17. Enrichment and isolation of Flavobacterium strains with tolerance to high concentrations of cesium ion.

    PubMed

    Kato, Souichiro; Goya, Eri; Tanaka, Michiko; Kitagawa, Wataru; Kikuchi, Yoshitomo; Asano, Kozo; Kamagata, Yoichi

    2016-01-01

    Interest in the interaction of microorganisms with cesium ions (Cs(+)) has arisen, especially in terms of their potent ability for radiocesium bioaccumulation and their important roles in biogeochemical cycling. Although high concentrations of Cs(+) display toxic effects on microorganisms, there have been only limited reports for Cs(+)-tolerant microorganisms. Here we report enrichment and isolation of Cs(+)-tolerant microorganisms from soil microbiota. Microbial community analysis revealed that bacteria within the phylum Bacteroidetes, especially Flavobacterium spp., dominated in enrichment cultures in the medium supplemented with 50 or 200 mM Cs(+), while Gammaproteobacteria was dominant in the control enrichment cultures (in the presence of 50 and 200 mM K(+) instead of Cs(+)). The dominant Flavobacterium sp. was successfully isolated from the enrichment culture and was closely related to Flavobacterium chungbukense with 99.5% identity. Growth experiments clearly demonstrated that the isolate has significantly higher tolerance to Cs(+) compared to its close relatives, suggesting the Cs(+)-tolerance is a specific trait of this strain, but not a universal trait in the genus Flavobacterium. Measurement of intracellular K(+) and Cs(+) concentrations of the Cs(+)-tolerant isolate and its close relatives suggested that the ability to maintain low intracellular Cs(+) concentration confers the tolerance against high concentrations of external Cs(+). PMID:26883718

  18. Enrichment and isolation of Flavobacterium strains with tolerance to high concentrations of cesium ion

    PubMed Central

    Kato, Souichiro; Goya, Eri; Tanaka, Michiko; Kitagawa, Wataru; Kikuchi, Yoshitomo; Asano, Kozo; Kamagata, Yoichi

    2016-01-01

    Interest in the interaction of microorganisms with cesium ions (Cs+) has arisen, especially in terms of their potent ability for radiocesium bioaccumulation and their important roles in biogeochemical cycling. Although high concentrations of Cs+ display toxic effects on microorganisms, there have been only limited reports for Cs+-tolerant microorganisms. Here we report enrichment and isolation of Cs+-tolerant microorganisms from soil microbiota. Microbial community analysis revealed that bacteria within the phylum Bacteroidetes, especially Flavobacterium spp., dominated in enrichment cultures in the medium supplemented with 50 or 200 mM Cs+, while Gammaproteobacteria was dominant in the control enrichment cultures (in the presence of 50 and 200 mM K+ instead of Cs+). The dominant Flavobacterium sp. was successfully isolated from the enrichment culture and was closely related to Flavobacterium chungbukense with 99.5% identity. Growth experiments clearly demonstrated that the isolate has significantly higher tolerance to Cs+ compared to its close relatives, suggesting the Cs+-tolerance is a specific trait of this strain, but not a universal trait in the genus Flavobacterium. Measurement of intracellular K+ and Cs+ concentrations of the Cs+-tolerant isolate and its close relatives suggested that the ability to maintain low intracellular Cs+ concentration confers the tolerance against high concentrations of external Cs+. PMID:26883718

  19. Daily variations of indoor air-ion and radon concentrations.

    PubMed

    Kolarz, P M; Filipović, D M; Marinković, B P

    2009-11-01

    Air-ions and radon are two atmospheric trace constituents which have two opposite effects on human health: the ions are beneficial, and radon gas is potentially lethal as it increases the risk of lung cancer. In the lower troposphere, radon is the most important generator of the air-ions. Ionization by cosmic rays and radioactive minerals is almost constant in daily cycles, and variation of air-ion concentrations is attributed to changes of the radon activity. Air-ion and radon concentrations in outdoor and indoor space and their vertical gradients in residential buildings were measured. Gerdien type air-ion detector "CDI-06" made in our laboratory and radon monitor "RAD7" were utilized for these measurements. Correlation coefficient between positive air-ion and Rn indoor concentrations was approximately 0.7. Outdoor and indoor peak values were simultaneous while vertical gradient of concentrations in indoor measurements was evident. The indoor experiments showed that positive air-ion concentration could be an alternative method of radon activity concentration evaluation. PMID:19700332

  20. Minanre Gas Concentrators For Air Sampling

    SciTech Connect

    Dr. Seung Ho Hong

    2001-03-01

    The goal of this project was to demonstrate the feasibility of a compact, lightweight, gas-sampling device with rapid-cycle-time characteristics. The highlights of our Phase I work include: (1) Demonstration of a compact gas sampler with integrated heater. This device has an order of magnitude greater adsorption capacity and much faster heating/cooling times than commercial sorbent tubes. (2) Completion of computational fluid dynamics modeling of the gas sampler to determine airflow characteristics for various design options. These modeling efforts guided the development and testing of the Mesochannel Gas Sampler prototype. (3) Testing of the Mesochannel Gas Sampler in parallel with tests of two packed-bed samplers. These tests showed the Mesochannel Gas Sampler represents a substantial improvement compared with the packed-bed approach. Our mesochannel heat-exchanger/adsorber architecture allows very efficient use of adsorbent mass, high adsorbent loadings, and very low pressure drop, which makes possible very high air-sampling rates using a simple, low-power fan. This device is well-suited for collecting samples of trace-level contaminants. The integrated heater, which forms the adsorbent-coated mesochannel walls, allows direct heating of the adsorbent and results in very rapid desorption of the adsorbed species. We believe the Mesochannel Gas Sampler represents a promising technology for the improvement of trace-contaminant detection limits. In our Phase II proposal, we outline several improvements to the gas sampler that will further improve its performance.

  1. Variations of 210Pb concentrations in surface air at Thessaloniki, Greece (40°N)

    NASA Astrophysics Data System (ADS)

    Ioannidou, A.; Kotsopoulou, E.; Karanatsiou, A.; Papastefanou, C.

    2012-04-01

    Atmospheric concentrations of 210Pb were measured over the year 2009 in ground level air at Thessaloniki, Northern Greece (40°62' N, 22°95'E). The mean activity concentrations of 210Pb in surface air have been found to be 671 ± 213 μBq m-3. The highest values of monthly atmospheric concentrations of 210Pb were observed in the autumn and the lowest in the spring period. The higher values of 210Pb during autumn were attributed to frequent inversion conditions of the surface layers, resulting in an enrichment of radon and its decay products in surface air. The lower values during the winter months might be due to the low emanation of radon from the frozen or snow-covered soil. The minima of 210Pb concentrations during spring might reflect on higher washout during this period, which results in less emanation of radon from saturated with water soil, resulting in less production of 210Pb near ground-level air. The relative high values during summer are probably due to the higher 222Rn exhalation from the ground and due to the higher air mixing within the troposphere, which has as a result to carry down to the surface layer 210Pb whose origin is older air masses which entered into the free troposphere.

  2. Short-term carbon cycling responses of a mature eucalypt woodland to gradual stepwise enrichment of atmospheric CO2 concentration.

    PubMed

    Drake, John E; Macdonald, Catriona A; Tjoelker, Mark G; Crous, Kristine Y; Gimeno, Teresa E; Singh, Brajesh K; Reich, Peter B; Anderson, Ian C; Ellsworth, David S

    2016-01-01

    Projections of future climate are highly sensitive to uncertainties regarding carbon (C) uptake and storage by terrestrial ecosystems. The Eucalyptus Free-Air CO2 Enrichment (EucFACE) experiment was established to study the effects of elevated atmospheric CO2 concentrations (eCO2 ) on a native mature eucalypt woodland with low fertility soils in southeast Australia. In contrast to other FACE experiments, the concentration of CO2 at EucFACE was increased gradually in steps above ambient (+0, 30, 60, 90, 120, and 150 ppm CO2 above ambient of ~400 ppm), with each step lasting approximately 5 weeks. This provided a unique opportunity to study the short-term (weeks to months) response of C cycle flux components to eCO2 across a range of CO2 concentrations in an intact ecosystem. Soil CO2 efflux (i.e., soil respiration or Rsoil ) increased in response to initial enrichment (e.g., +30 and +60 ppm CO2 ) but did not continue to increase as the CO2 enrichment was stepped up to higher concentrations. Light-saturated photosynthesis of canopy leaves (Asat ) also showed similar stimulation by elevated CO2 at +60 ppm as at +150 ppm CO2 . The lack of significant effects of eCO2 on soil moisture, microbial biomass, or activity suggests that the increase in Rsoil likely reflected increased root and rhizosphere respiration rather than increased microbial decomposition of soil organic matter. This rapid increase in Rsoil suggests that under eCO2, additional photosynthate was produced, transported belowground, and respired. The consequences of this increased belowground activity and whether it is sustained through time in mature ecosystems under eCO2 are a priority for future research. PMID:26426394

  3. Short-term carbon cycling responses of a mature eucalypt woodland to gradual stepwise enrichment of atmospheric CO2 concentration.

    PubMed

    Drake, John E; Macdonald, Catriona A; Tjoelker, Mark G; Crous, Kristine Y; Gimeno, Teresa E; Singh, Brajesh K; Reich, Peter B; Anderson, Ian C; Ellsworth, David S

    2016-01-01

    Projections of future climate are highly sensitive to uncertainties regarding carbon (C) uptake and storage by terrestrial ecosystems. The Eucalyptus Free-Air CO2 Enrichment (EucFACE) experiment was established to study the effects of elevated atmospheric CO2 concentrations (eCO2 ) on a native mature eucalypt woodland with low fertility soils in southeast Australia. In contrast to other FACE experiments, the concentration of CO2 at EucFACE was increased gradually in steps above ambient (+0, 30, 60, 90, 120, and 150 ppm CO2 above ambient of ~400 ppm), with each step lasting approximately 5 weeks. This provided a unique opportunity to study the short-term (weeks to months) response of C cycle flux components to eCO2 across a range of CO2 concentrations in an intact ecosystem. Soil CO2 efflux (i.e., soil respiration or Rsoil ) increased in response to initial enrichment (e.g., +30 and +60 ppm CO2 ) but did not continue to increase as the CO2 enrichment was stepped up to higher concentrations. Light-saturated photosynthesis of canopy leaves (Asat ) also showed similar stimulation by elevated CO2 at +60 ppm as at +150 ppm CO2 . The lack of significant effects of eCO2 on soil moisture, microbial biomass, or activity suggests that the increase in Rsoil likely reflected increased root and rhizosphere respiration rather than increased microbial decomposition of soil organic matter. This rapid increase in Rsoil suggests that under eCO2, additional photosynthate was produced, transported belowground, and respired. The consequences of this increased belowground activity and whether it is sustained through time in mature ecosystems under eCO2 are a priority for future research.

  4. Concentrations of selected contaminants in cabin air of airbus aircrafts.

    PubMed

    Dechow, M; Sohn, H; Steinhanses, J

    1997-07-01

    The concentrations of selected air quality parameters in aircraft cabins were investigated including particle numbers in cabin air compared to fresh air and recirculation air, the microbiological contamination and the concentration of volatile organic compounds (VOC). The Airbus types A310 of Swissair and A340 of Lufthansa were used for measurements. The particles were found to be mainly emitted by the passengers, especially by smokers. Depending on recirculation filter efficiency the recirculation air contained a lower or equal amount of particles compared to the fresh air, whereas the amount of bacteria exceeded reported concentrations within other indoor spaces. The detected species were mainly non-pathogenic, with droplet infection over short distances identified as the only health risk. The concentration of volatile organic compounds (VOC) were well below threshold values. Ethanol was identified as the compound with the highest amount in cabin air. Further organics were emitted by the passengers--as metabolic products or by smoking--and on ground as engine exhaust (bad airport air quality). Cleaning agents may be the source of further compounds.

  5. Sustained enhancement of photosynthesis in mature deciduous forest trees after 8 years of free air CO(2) enrichment.

    PubMed

    Bader, Martin Karl-Friedrich; Siegwolf, Rolf; Körner, Christian

    2010-10-01

    Carbon uptake by forests constitutes half of the planet's terrestrial net primary production; therefore, photosynthetic responses of trees to rising atmospheric CO(2) are critical to understanding the future global carbon cycle. At the Swiss Canopy Crane, we investigated gas exchange characteristics and leaf traits in five deciduous tree species during their eighth growing season under free air carbon dioxide enrichment in a 35-m tall, ca. 100-year-old mixed forest. Net photosynthesis of upper-canopy foliage was 48% (July) and 42% (September) higher in CO(2)-enriched trees and showed no sign of down-regulation. Elevated CO(2) had no effect on carboxylation efficiency (V (cmax)) or maximal electron transport (J (max)) driving ribulose-1,5-bisphosphate (RuBP) regeneration. CO(2) enrichment improved nitrogen use efficiency, but did not affect leaf nitrogen (N) concentration, leaf thickness or specific leaf area except for one species. Non-structural carbohydrates accumulated more strongly in leaves grown under elevated CO(2) (largely driven by Quercus). Because leaf area index did not change, the CO(2)-driven stimulation of photosynthesis in these trees may persist in the upper canopy under future atmospheric CO(2) concentrations without reductions in photosynthetic capacity. However, given the lack of growth stimulation, the fate of the additionally assimilated carbon remains uncertain.

  6. CONCENTRATIONS OF TOXIC AIR POLLUTANTS IN THE U.S. SIMULATED BY AN AIR QUALITY MODEL

    EPA Science Inventory

    As part of the US National Air Toxics Assessment, we have applied the Community Multiscale Air Quality Model, CMAQ, to study the concentrations of twenty gas-phase, toxic, hazardous air pollutants (HAPs) in the atmosphere over the continental United States. We modified the Carbo...

  7. Ambient air concentrations of particulate matter from passenger cars.

    PubMed

    Schürmann, D

    1989-01-01

    Using our measurement results on particulate emissions from passenger cars we have calculated ambient air concentrations for various US and European scenarios. This was carried out with the help of mathematical dispersion models for different traffic situations including street canyons and motorways. We have been very conservative in our choice of the scenarios, i.e. we have always used situations in which there are very high stress levels (e.g. constantly high traffic flow instead of average traffic flow). Finally, the thus determined air concentrations are compared with the corresponding air quality standard available from the literature.

  8. Ambient air concentrations of particulate matter from passenger cars.

    PubMed

    Schürmann, D

    1989-01-01

    Using our measurement results on particulate emissions from passenger cars we have calculated ambient air concentrations for various US and European scenarios. This was carried out with the help of mathematical dispersion models for different traffic situations including street canyons and motorways. We have been very conservative in our choice of the scenarios, i.e. we have always used situations in which there are very high stress levels (e.g. constantly high traffic flow instead of average traffic flow). Finally, the thus determined air concentrations are compared with the corresponding air quality standard available from the literature. PMID:2484034

  9. Changes in Belowground Carbon Cycling After 10 Years at the Duke Free-Air CO2 Enrichment (FACE) Experiment

    NASA Astrophysics Data System (ADS)

    Jackson, R. B.; Cook, C. W.; Pippen, J. S.

    2006-05-01

    Carbon dioxide concentrations are increasing rapidly in the earth's atmosphere and have risen by a third since the start of the industrial revolution. Beginning in 1996, the Duke Free-Air CO2 Enrichment (FACE) experiment has exposed a loblolly pine forest to an additional 200 parts per million CO2 (high CO2 treatment) compared to trees at ambient CO2. Root biomass has increased significantly at high CO2, as have soil respiration and the concentration of CO2 in the soil at different depths. Peak changes for root biomas, soil respiration, and many other variables occur in mid summer, with responses diminishing or disappearing in winter. This presentation will review the changes over the first decade of the experiment, emphasizing results from the most recent three years.

  10. HIGH ARSENIC CONCENTRATIONS AND ENRICHED SULFUR AND OXYGEN ISOTOPES IN A FRACTURED-BEDROCK GROUND-WATER SYSTEM

    EPA Science Inventory

    Elevated arsenic concentrations are coincident with enriched sulfur and oxygen isotopes of sulfate in bedrock ground water within Kelly's Cove watershed, Northport, Maine, USA. Interpretation of the data is complicated by the lack of correlations between sulfate concentrations an...

  11. Air Shipment of Highly Enriched Uranium Spent Nuclear Fuel from Romania

    SciTech Connect

    K. J. Allen; I. Bolshinsky; L. L. Biro; M. E. Budu; N. V. Zamfir; M. Dragusin

    2010-07-01

    Romania safely air shipped 23.7 kilograms of Russian origin highly enriched uranium (HEU) spent nuclear fuel from the VVR S research reactor at Magurele, Romania, to the Russian Federation in June 2009. This was the world’s first air shipment of spent nuclear fuel transported in a Type B(U) cask under existing international laws without special exceptions for the air transport licenses. This shipment was coordinated by the Russian Research Reactor Fuel Return Program (RRRFR), part of the U.S. Department of Energy Global Threat Reduction Initiative (GTRI), in cooperation with the Romania National Commission for Nuclear Activities Control (CNCAN), the Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH), and the Russian Federation State Corporation Rosatom. The shipment was transported by truck to and from the respective commercial airports in Romania and the Russian Federation and stored at a secure nuclear facility in Russia where it will be converted into low enriched uranium. With this shipment, Romania became the 3rd country under the RRRFR program and the 14th country under the GTRI program to remove all HEU. This paper describes the work, equipment, and approvals that were required to complete this spent fuel air shipment.

  12. Indoor Air VOC Concentrations in Suburban and Rural New Jersey

    PubMed Central

    WEISEL, CLIFFORD P.; ALIMOKHTARI, SHAHNAZ; SANDERS, PAUL F.

    2014-01-01

    Indoor VOC air concentrations of many compounds are higher than outdoor concentrations due to indoor sources. However, most studies have measured residential indoor air in urban centers so the typical indoor air levels in suburban and rural regions have not been well characterized. Indoor VOC air concentrations were measured in 100 homes in suburban and rural areas in NJ to provide background levels for investigations of the impact from subsurface contamination sources. Of the 57 target compounds, 23 were not detected in any of the homes, and 14 compounds were detected in at least 50% of the homes with detection limits of ~1 μg/m3. The common compounds identified included aromatic and aliphatic hydrocarbons from mobile sources, halogenated hydrocarbons commonly used in consumer products or from chlorinated drinking water, acetone and 2-butanone emitted from cosmetic products, and Freons. Typical concentrations were in the low μg/m3 range, though values of tens, hundreds or even thousands of μg/m3 were measured in individual homes in which activities related to specific sources of VOCs were reported. Compounds with known similar sources were highly correlated. The levels observed are consistent with concentrations found in the air of urban homes. PMID:19068799

  13. Indoor air VOC concentrations in suburban and rural New Jersey.

    PubMed

    Weisel, Clifford P; Alimokhtari, Shahnaz; Sanders, Paul F

    2008-11-15

    Indoor VOC air concentrations of many compounds are higher than outdoor concentrations due to indoor sources. However, most studies have measured residential indoor air in urban centers so the typical indoor air levels in suburban and rural regions have not been well characterized. Indoor VOC air concentrations were measured in 100 homes in suburban and rural areas in NJ to provide background levels for investigations of the impact from subsurface contamination sources. Of the 57 target compounds, 23 were not detected in any of the homes, and 14 compounds were detected in at least 50% of the homes with detection limits of approximately 1 microg/m3. The common compounds identified included aromatic and aliphatic hydrocarbons from mobile sources, halogenated hydrocarbons commonly used in consumer products or from chlorinated drinking water, acetone and 2-butanone emitted from cosmetic products, and Freons. Typical concentrations were in the low microg/m3 range, though values of tens, hundreds or even thousands of microg/m3 were measured in individual homes in which activities related to specific sources of VOCs were reported. Compounds with known similar sources were highly correlated. The levels observed are consistent with concentrations found in the air of urban homes. PMID:19068799

  14. Ultralow Concentration Mercury Treatment Using Chemical Reduction and Air Stripping

    SciTech Connect

    Looney, B.B.

    2001-05-21

    Field, laboratory and engineering data confirmed the efficacy of chemical reduction and air stripping as an ultralow concentration mercury treatment concept for water containing Hg(II). The simple process consists of dosing the water with low levels of stannous chloride (Sn(II)) to cover the mercury to Hg degrees. This mercury species can easily be removed from the water by air stripping or sparging.

  15. Concentrations of propoxur in air following repeated indoor applications.

    PubMed

    Miller, C W; Shafik, T M

    1974-01-01

    The insecticide propoxur was applied as 2 non-overlapping bands approximately 1 m wide to the interior of houses in El Salvador once every 35 days for a period of 9 months. Air samples were collected from the interior of the houses once every seventh day during the entire period. In the study area, air temperatures remain relatively constant, while rainfall varies seasonally. It was found that volatilization of propoxur, as determined by the amounts detectable in air, represented release of the chemical from the treated surface and that the volatilization process was most influenced by the amount of moisture present in the air. Higher air concentrations of propoxur occurred during periods of high relative humidity than in periods of low relative humidity. The principles involved in this process and its bearing on the value of propoxur in malaria control programmes are discussed.

  16. Research Reactor Preparations for the Air Shipment of Highly Enriched Uranium from Romania

    SciTech Connect

    K. J. Allen; I. Bolshinsky; L. L. Biro; M. E. Budu; N. V. Zamfir; M. Dragusin; C. Paunoiu; M. Ciocanescu

    2010-03-01

    In June 2009 two air shipments transported both unirradiated (fresh) and irradiated (spent) Russian-origin highly enriched uranium (HEU) nuclear fuel from two research reactors in Romania to the Russian Federation for conversion to low enriched uranium. The Institute for Nuclear Research at Pitesti (SCN Pitesti) shipped 30.1 kg of HEU fresh fuel pellets to Dimitrovgrad, Russia and the Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH) shipped 23.7 kilograms of HEU spent fuel assemblies from the VVR S research reactor at Magurele, Romania, to Chelyabinsk, Russia. Both HEU shipments were coordinated by the Russian Research Reactor Fuel Return Program (RRRFR) as part of the U.S. Department of Energy Global Threat Reduction Initiative (GTRI), were managed in Romania by the National Commission for Nuclear Activities Control (CNCAN), and were conducted in cooperation with the Russian Federation State Corporation Rosatom and the International Atomic Energy Agency. Both shipments were transported by truck to and from respective commercial airports in Romania and the Russian Federation and stored at secure nuclear facilities in Russia until the material is converted into low enriched uranium. These shipments resulted in Romania becoming the 3rd country under the RRRFR program and the 14th country under the GTRI program to remove all HEU. This paper describes the research reactor preparations and license approvals that were necessary to safely and securely complete these air shipments of nuclear fuel.

  17. Ozone concentrations in air flowing into New York State

    NASA Astrophysics Data System (ADS)

    Aleksic, Nenad; Kent, John; Walcek, Chris

    2016-09-01

    Ozone (O3) concentrations measured at Pinnacle State Park (PSPNY), very close to the southern border of New York State, are used to estimate concentrations in air flowing into New York. On 20% of the ozone season (April-September) afternoons from 2004 to 2015, mid-afternoon 500-m back trajectories calculated from PSPNY cross New York border from the south and spend less than three hours in New York State, in this area of negligible local pollution emissions. One-hour (2p.m.-3p.m.) O3 concentrations during these inflowing conditions were 46 ± 13 ppb, and ranged from a minimum of 15 ppb to a maximum of 84 ppb. On average during 2004-2015, each year experienced 11.8 days with inflowing 1-hr O3 concentrations exceeding 50 ppb, 4.3 days with O3 > 60 ppb, and 1.5 days had O3 > 70 ppb. During the same period, 8-hr average concentrations (10a.m. to 6p.m.) exceeded 50 ppb on 10.0 days per season, while 3.9 days exceeded 60 ppb, and 70 ppb was exceeded 1.2 days per season. Two afternoons of minimal in-state emission influences with high ozone concentrations were analyzed in more detail. Synoptic and back trajectory analysis, including comparison with upwind ozone concentrations, indicated that the two periods were characterized as photo-chemically aged air containing high inflowing O3 concentrations most likely heavily influenced by pollution emissions from states upwind of New York including Pennsylvania, Tennessee, West Virginia, and Ohio. These results suggest that New York state-level attempts to comply with National Ambient Air Quality Standards by regulating in-state O3 precursor NOx and organic emissions would be very difficult, since air frequently enters New York State very close to or in excess of Federal Air Quality Standards.

  18. AIR SHIPMENT OF HIGHLY ENRICHED URANIUM SPENT NUCLEAR FUEL FROM ROMANIA AND LIBYA

    SciTech Connect

    Christopher Landers; Igor Bolshinsky; Ken Allen; Stanley Moses

    2010-07-01

    In June 2009 Romania successfully completed the world’s first air shipment of highly enriched uranium (HEU) spent nuclear fuel transported in Type B(U) casks under existing international laws and without special exceptions for the air transport licenses. Special 20-foot ISO shipping containers and cask tiedown supports were designed to transport Russian TUK 19 shipping casks for the Romanian air shipment and the equipment was certified for all modes of transport, including road, rail, water, and air. In December 2009 Libya successfully used this same equipment for a second air shipment of HEU spent nuclear fuel. Both spent fuel shipments were transported by truck from the originating nuclear facilities to nearby commercial airports, were flown by commercial cargo aircraft to a commercial airport in Yekaterinburg, Russia, and then transported by truck to their final destinations at the Production Association Mayak facility in Chelyabinsk, Russia. Both air shipments were performed under the Russian Research Reactor Fuel Return Program (RRRFR) as part of the U.S. National Nuclear Security Administration (NNSA) Global Threat Reduction Initiative (GTRI). The Romania air shipment of 23.7 kg of HEU spent fuel from the VVR S research reactor was the last of three HEU fresh and spent fuel shipments under RRRFR that resulted in Romania becoming the 3rd RRRFR participating country to remove all HEU. Libya had previously completed two RRRFR shipments of HEU fresh fuel so the 5.2 kg of HEU spent fuel air shipped from the IRT 1 research reactor in December made Libya the 4th RRRFR participating country to remove all HEU. This paper describes the equipment, preparations, and license approvals required to safely and securely complete these two air shipments of spent nuclear fuel.

  19. Synthesis of polymorph A-enriched beta zeolites in a HF-concentrated system.

    PubMed

    Zhang, Guanqun; Wang, Bingchun; Zhang, Weiping; Li, Mingrun; Tian, Zhijian

    2016-04-21

    Polymorph A-enriched beta zeolites were synthesized by employing high HF concentrations in the synthesis medium. The polymorphic compositions of the synthesized beta zeolites were determined by the complementary characterization methods (19)F NMR analysis and PXRD simulation. With a variety of SDAs, a high HF concentration (HF/SDA > 1.0) in the synthesis medium results in the A-rich feature (55-65% A) of beta zeolites, while a moderate HF concentration only results in typical beta zeolites. A systematic study on the synthesis conditions reveals the existence of a buffered system of H(+) and F(-) formed in the highly HF-concentrated medium. This buffer results in a small but continuous supply of F(-) during zeolite crystallization, in contrast to the conventional fluoride route where all F(-) are discharged all-at-once at the initial stage. PMID:26974286

  20. Spectra of concentration of air pollution for turbulent convection

    SciTech Connect

    Patel, S.R.

    1996-12-31

    Very recently the study of formation and destruction of photochemical smog is increasing at both small and large scale. Also the transport of chemical species through the Planetary Boundary Layer (PBL) of the atmosphere is a key of the global change problem and will have to be parameterized more reliably than in the past. Further, in the air pollution modeling, the usual practice of neglecting the concentration correlation in the atmospheric photochemical reaction has recently been recognized as a source of serious error. So, it is important to study the various aspects of the concentration fluctuations (of air pollution) with chemical reaction. A model of the spectrum of concentration of air pollution with chemical reaction has been developed using the models of Hill and Hill and Clifford. The results obtained are applicable for arbitrary Schmidt number. Further, for the case of pure mixing (without chemical reaction) and the concentration replaced by temperature, the form of the spectra obtained here reduces to the form obtained by Hill and Clifford. This study also shows that, in the case of pure mixing, the concentration decays in a natural manner, but if the concentration selected is that of the chemical reactant, then the effect is that the dispersion of the concentration is much more rapid.

  1. Reduction of nitrate losses from filter and impactor samplers by means of concentration enrichment

    NASA Astrophysics Data System (ADS)

    Chang, Ming Chih; Sioutas, Constantinos; Kim, Seongheon; Gong, Henry; Linn, William S.

    Sampling errors (artifacts) have greatly affected the precision of the quantitative analysis of volatile species, such as particulate ammonium nitrate. This work presents the effect of the enrichment in concentration of particulate nitrate in reducing volatilization losses in impactors and Teflon filter samplers. During the performance characterization of an ambient fine particle concentrator developed by Sioutas et al. (1995a, Environmental Health Perspectives 103, 172-177, 1995b, Inhalation Toxicology, 7, 633-644, 1977, Journal of Aerosol Science 28, 1057-1071) losses of ambient ammonium nitrate from denuded and undenuded Teflon filter samplers as well as the microorifice uniform deposit impactor (MOUDI) were evaluated in Los Angeles, CA, an area where ammonium nitrate constitutes a major component of ambient fine particulate matter. The field study data were compared to those predicted theoretically for a given set of gas and particulate nitrate concentrations, temperature and relative humidity. Both theoretical and experimental results indicated that the ratio of nitrate gas-to-particle concentration affects significantly the volatilization loss, with higher volatilization losses occurring at higher gas-to-particle concentration values. The concentration enrichment of particulate-phase nitrate resulted in reducing evaporation losses from the MOUDI from 20-50% to less than 10%. Losses of nitrate from denuded Teflon filters were reduced from 60-95% to less than 30%, and for undenuded Teflon filters from 30-80% to less than 5%. Our study concluded that nitrate losses from impactor, denuded and undenuded Teflon filter samplers could be virtually eliminated by placing the sampler downstream of a particle concentrator with a small cutpoint (i.e., 0.1 μm).

  2. Litterfall 15N abundance indicates declining soil nitrogen availability in a free-air CO2 enrichment experiment.

    PubMed

    Garten, Charles T; Iversen, Colleen M; Norby, Richard J

    2011-01-01

    Forest productivity increases in response to carbon dioxide (CO2) enrichment of the atmosphere. However, in nitrogen-limited ecosystems, increased productivity may cause a decline in soil nitrogen (N) availability and induce a negative feedback on further enhancement of forest production. In a free-air CO2 enrichment (FACE) experiment, the response of sweetgum (Liquidambar styraciflua L.) productivity to elevated CO2 concentrations [CO2] has declined over time, but documenting an associated change in soil N availability has been difficult. Here we assess the time history of soil N availability through analysis of natural 15N abundance in archived samples of freshly fallen leaf litterfall. Litterfall delta15N declined from 1998 to 2005, and the rate of decline was significantly faster in elevated [CO2]. Declining leaf litterfall delta15N is indicative of a tighter ecosystem N cycle and more limited soil N availability. By integrating N availability over time and throughout the soil profile, temporal dynamics in leaf litterfall delta15N provide a powerful tool for documenting changes in N availability and the critical feedbacks between C and N cycles that will control forest response to elevated atmospheric CO2 concentrations.

  3. Temperature and concentration transients in the aluminum-air battery

    SciTech Connect

    Homsy, R.V.

    1981-08-26

    Coupled conservation equations of heat and mass transfer are solved, that predict temperature and concentration of the electrolyte of an aluminum-air battery system upon start-up and shutdown. Results of recent laboratory studies investigating the crystallization kinetics and solubility of the caustic-aluminate electrolyte system are used in the predictions. Temperature and concentration start-up transients are short, while during standby conditions, temperature increases to a maximum and decreases slowly.

  4. Electron concentration distribution in a glow discharge in air flow

    NASA Astrophysics Data System (ADS)

    Mukhamedzianov, R. B.; Gaisin, F. M.; Sabitov, R. A.

    1989-04-01

    Electron concentration distributions in a glow discharge in longitudinal and vortex air flows are determined from the attenuation of the electromagnetic wave passing through the plasma using microwave probes. An analysis of the distribution curves obtained indicates that electron concentration decreases in the direction of the anode. This can be explained by charge diffusion toward the chamber walls and electron recombination and sticking within the discharge.

  5. Measuring radon concentration in air using a diffusion cloud chamber

    NASA Astrophysics Data System (ADS)

    Cases, R.; Ros, E.; Zúñiga, J.

    2011-09-01

    Radon concentration in air is a major concern in lung cancer studies. A traditional technique used to measure radon abundance is the charcoal canister method. We propose a novel technique using a diffusion cloud chamber. This technique is simpler and can easily be used for physics demonstrations for high school and university students.

  6. Auditing and assessing air quality in concentrated feeding operations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential adverse effects of concentrated animal feeding operations (CAFO) on the environment are a growing concern. The air quality issues of most concerns to CAFO vary, but generally include ammonia, hydrogen sulfide, particulate matter (PM), volatile organic compounds (VOC), green house gase...

  7. Experimental and predicted approaches for biomass gasification with enriched air-steam in a fluidised bed.

    PubMed

    Fu, Qirang; Huang, Yaji; Niu, Miaomiao; Yang, Gaoqiang; Shao, Zhiwei

    2014-10-01

    Thermo-chemical gasification of sawdust refuse-derived fuel was performed on a bench-scale fluidised bed gasifier with enriched air and steam as fluidising and oxidising agents. Dolomite as a natural mineral catalyst was used as bed material to reform tars and hydrocarbons. A series of experiments were carried out under typical operating conditions for gasification, as reported in the article. A modified equilibrium model, based on equilibrium constants, was developed to predict the gasification process. The sensitivity analysis of operating parameters, such as the fluidisation velocity, oxygen percentage of the enriched air and steam to biomass ratios on the produced gas composition, lower heating value, carbon conversion and cold gas efficiency was investigated. The results showed that the predicted syngas composition was in better agreement with the experimental data compared with the original equilibrium model. The higher fluidisation velocity enhanced gas-solid mixing, heat and mass transfers, and carbon fines elutriation, simultaneously. With the increase of oxygen percentage from 21% to 45%, the lower heating value of syngas increased from 5.52 MJ m(-3) to 7.75 MJ m(-3) and cold gas efficiency from 49.09% to 61.39%. The introduction of steam improved gas quality, but a higher steam to biomass ratio could decrease carbon conversion and gasification efficiency owing to a low steam temperature. The optimal value of steam to biomass ratio in this work was 1.0. PMID:25265865

  8. Final Technical Report: Science and technology reviews of FACE[Free Air Carbon Enrichment

    SciTech Connect

    Strain, Boyd R.

    1998-03-23

    The purpose of this grant was to bring together the principals of all known facilities that had been developed, principals who had submitted proposals to develop FACE facilities, and principals who want to develop proposals for facilities. In addition, critical program personnel from potential funding agencies and a few high level science administrators were invited to observe the proceedings and to visit a working FACE facility. The objectives of this study are to conduct a three-day international meeting on scientific aspects of research with the new and developing free air carbon enrichment (FACE) technology. Immediately following the science meeting, conduct a two-day international meeting on experimental protocols to be applied in FACE research. To conduct a four day international meeting on the assessment of the responses of forest ecosystems to elevated atmospheric carbon dioxide. The three meetings supported by this grant were all highly successful meetings and resulted in the formation of an organized and identified working group with the acronym InterFACE (International Free-Air Carbon Dioxide Enrichment) working group.

  9. Experimental and predicted approaches for biomass gasification with enriched air-steam in a fluidised bed.

    PubMed

    Fu, Qirang; Huang, Yaji; Niu, Miaomiao; Yang, Gaoqiang; Shao, Zhiwei

    2014-10-01

    Thermo-chemical gasification of sawdust refuse-derived fuel was performed on a bench-scale fluidised bed gasifier with enriched air and steam as fluidising and oxidising agents. Dolomite as a natural mineral catalyst was used as bed material to reform tars and hydrocarbons. A series of experiments were carried out under typical operating conditions for gasification, as reported in the article. A modified equilibrium model, based on equilibrium constants, was developed to predict the gasification process. The sensitivity analysis of operating parameters, such as the fluidisation velocity, oxygen percentage of the enriched air and steam to biomass ratios on the produced gas composition, lower heating value, carbon conversion and cold gas efficiency was investigated. The results showed that the predicted syngas composition was in better agreement with the experimental data compared with the original equilibrium model. The higher fluidisation velocity enhanced gas-solid mixing, heat and mass transfers, and carbon fines elutriation, simultaneously. With the increase of oxygen percentage from 21% to 45%, the lower heating value of syngas increased from 5.52 MJ m(-3) to 7.75 MJ m(-3) and cold gas efficiency from 49.09% to 61.39%. The introduction of steam improved gas quality, but a higher steam to biomass ratio could decrease carbon conversion and gasification efficiency owing to a low steam temperature. The optimal value of steam to biomass ratio in this work was 1.0.

  10. [Responses of agricultural crops of free-air CO2 enrichment].

    PubMed

    Kimball, B A; Zhu, Jianguo; Cheng, Lei; Kobayashi, K; Bindi, M

    2002-10-01

    Over the past decade, free-air CO2 enrichment (FACE) experiments have been conducted on several agricultural crops: wheat(Triticum aestivum L.), perennial ryegrass (Lolium perenne), and rice(Oryza sativa L.) which are C3 grasses; sorghum (Sorghum bicolor (L.) Möench), a C4 grass; white clover (Trifolium repens), a C3 legume; potato (Solanum tuberosum L.), a C3 forb with tuber storage; and cotton (Gossypium hirsutum L.) and grape (Vitis vinifera L.) which are C3 woody perennials. Using reports from these experiments, the relative responses of these crops was discussed with regard to photosynthesis, stomatal conductance, canopy temperature, water use, water potential, leaf area index, shoot and root biomass accumulation, agricultural yield, radiation use efficiency, specific leaf area, tissue nitrogen concentration, nitrogen yield, carbohydrate concentration, phenology, soil microbiology, soil respiration, trace gas emissions, and soil carbon sequestration. Generally, the magnitude of these responses varied with the functional type of plant and with the soil nitrogen and water status. As expected, the elevated CO2 increased photosynthesis and biomass production and yield substantially in C3 species, but little in C4, and it decreased stomatal conductance and transpiration in both C3 and C4 species and greatly improved water-use efficiency in all the crops. Growth stimulations were as large or larger under water-stress compared to well-watered conditions. Growth stimulations of non-legumes were reduced at low soil nitrogen, whereas elevated CO2 strongly stimulated the growth of the clover legume both at ample and under low N conditions. Roots were generally stimulated more than shoots. Woody perennials had larger growth responses to elevated CO2, while at the same time, their reductions in stomatal conductance were smaller. Tissue nitrogen concentrations went down while carbohydrate and some other carbon-based compounds went up due to elevated CO2, with leaves and

  11. [Effects of free-air CO2 enrichment on rice canopy microlimate].

    PubMed

    Luo, Weihong; Mayumi, Yoshimoto; Dai, Jianfeng; Zhu, Jianguo; Han, Yong; Liu, Gan

    2002-10-01

    In this study, the free-air CO2 enrichment (FACE) system (setup at at Anzhen, Wuxi, Jiangsu Province in 2001) was used to investigate the effects of FACE on rice canopy microclimate. The rice canopy microclimate observations were carried out from August 26 to October 13, 2001, when the rice crops were at the heading to maturing development stage. The results showed that FACE reduced the rice leaf stomatal conductance. The rice leaf stomatal conductance difference between FACE and ambient was larger among upper layer leaves than among lower layer leaves and at heading and milk filling stages than at maturing stage. FACE increased daytime rice canopy temperature but had little effect on nighttime rice canopy temperature. The daytime rice canopy temperature difference between FACE and ambient was larger at heading and milk filling stages than at maturing stage. From heading to flowering, the daily maximum rice canopy temperature difference between FACE and ambient reached 1.2 degrees C under fine weather condition. The average daytime rice canopy temperature from flowering to maturing stage was about 0.43 degree C. Daytime air temperature inside rice canopy was also affected by FACE. Daytime air temperature inside rice canopy was higher in FACE plot than in ambient plot. The value of daytime air temperature difference between FACE and ambient increased with the increase of solar radiation and varied with height. The maximum daytime air temperature difference between FACE and ambient varied between 0.47-1.2 degrees C and 0.37-0.8 degree C at middle of canopy and canopy height, respectively. Air humidity and nighttime air temperature inside rice canopy were not significantly affected by FACE. These results indicate that FACE reducing rice leaf stomatal conductance was the major cause of the increase of canopy temperature and inside canopy air temperature in FACE plot. The higher canopy temperature and inside canopy air temperature in FACE plot resulted in the earlier

  12. Passive dosimetry as an alternative technique to dynamic enrichment of organic pollutants of indoor air.

    PubMed

    Zabiegała, B; Przyjazny, A; Namieśnik, J

    1999-01-01

    Evaluation of the quality of indoor air was carried out in 20 apartments, 3 offices, and 3 laboratories in the Tricity area in Poland with reference to concentrations of selected volatile organic compounds (VOCs), such as benzene, toluene, butyl acetate, ethylbenzene, m-xylene, styrene, and m-dichlorobenzene. The time dependence of concentrations of selected VOCs in a newly erected building was studied. Two different techniques were used for the isolation and preconcentration of analytes from air samples: a passive method employing a home-made permeation-type passive sampler and a dynamic method based on a sorption tube. In both cases, activated charcoal was used as a sorption medium (trap packing). The sorption tube was used to validate the results obtained by the passive method, as well. In the majority of dwellings examined, the concentrations of air pollutants were relatively low and did not exceed the MAC values. No significant differences were observed between MAC concentrations determined by using the passive or the dynamic method of air sampling. The results obtained by both sampling methods were characterized by similar precision.

  13. Predicting indoor pollutant concentrations, and applications to air quality management

    SciTech Connect

    Lorenzetti, David M.

    2002-10-01

    Because most people spend more than 90% of their time indoors, predicting exposure to airborne pollutants requires models that incorporate the effect of buildings. Buildings affect the exposure of their occupants in a number of ways, both by design (for example, filters in ventilation systems remove particles) and incidentally (for example, sorption on walls can reduce peak concentrations, but prolong exposure to semivolatile organic compounds). Furthermore, building materials and occupant activities can generate pollutants. Indoor air quality depends not only on outdoor air quality, but also on the design, maintenance, and use of the building. For example, ''sick building'' symptoms such as respiratory problems and headaches have been related to the presence of air-conditioning systems, to carpeting, to low ventilation rates, and to high occupant density (1). The physical processes of interest apply even in simple structures such as homes. Indoor air quality models simulate the processes, such as ventilation and filtration, that control pollutant concentrations in a building. Section 2 describes the modeling approach, and the important transport processes in buildings. Because advection usually dominates among the transport processes, Sections 3 and 4 describe methods for predicting airflows. The concluding section summarizes the application of these models.

  14. Estimating the radon concentration in water and indoor air.

    PubMed

    Maged, A F

    2009-05-01

    The paper presents the results of radon concentration measurements in the vicinity of water, indoor air and in contact to building walls. The investigations were carried out using CR-39 track detectors. Samples of ground water flowing out of many springs mostly in Arabian Gulf area except one from Germany have been studied. The results are compared with international recommendations and the values are found to be lower than the recommended value. Measuring the mean indoor radon concentrations in air and in contact to building walls in the dwellings of Kuwait University Campus were found 24.2 +/- 7.7, and 462 +/- 422 Bq m(-3) respectively. These values lead to average effective dose equivalent rates of 1.3 +/- 0.4 and 23 +/- 21 mSv year(-1), respectively.

  15. Glucose and glycerol concentrations and their tracer enrichment measurements using liquid chromatography tandem mass spectrometry.

    PubMed

    Bornø, Andreas; Foged, Lene; van Hall, Gerrit

    2014-10-01

    The present study describes a new liquid chromatography tandem mass spectrometry method for high-throughput quantification of glucose and glycerol in human plasma using stable isotopically labeled internal standards and is suitable for simultaneous measurements of glucose and glycerol enrichments in connection to in vivo metabolic studies investigating glucose turnover and lipolytic rate. Moreover, in order to keep up with this new fast analysis, simple derivatization procedures have been developed. Prior to analysis, glucose and glycerol were derivatized using benzoyl chloride in order to form benzoylated derivatives via new simplified fast procedures. For glucose, two internal standards were evaluated, [U-(13) C(6)]glucose and [U-(13) C(6), D(7)]glucose, and for glycerol, [U-(13) C(3), D(8)]glycerol was used. The method was validated by means of calibration curves, quality control samples, and plasma samples spiked with [6,6-D(2)]glucose, [U-(13) C(6)]glucose, and [1,1,2,3,3-D(5)]glycerol in order to test accuracy, precision, and recovery of the method. Moreover, post preparative and freeze-thaw sample stability were tested. The correlation of calibration curves for the glucose concentration were r(2) = 0.9998 for [U-(13) C(6)]glucose and r(2) = 0.9996 for [U-(13) C(6), D(7)]glucose, and r(2) = 0.9995 for the glycerol concentration. Interday accuracy for glucose using [U-(13) C(6)]glucose and glycerol determined in spiked plasma were respectively 103.5% and 106.0%, and the coefficients of variation were 2.0% and 9.7%, respectively. After derivatization, plasma samples were stable for at least 14 days. In conclusion, we have developed and validated a novel, accurate, and sensitive high-throughput liquid chromatography tandem mass spectrometry method for simultaneous determination of glucose and glycerol concentrations and enrichment of infused tracers most commonly used in human metabolic kinetic studies.

  16. Variability of air ion concentrations in urban Paris

    NASA Astrophysics Data System (ADS)

    Dos Santos, V. N.; Herrmann, E.; Manninen, H. E.; Hussein, T.; Hakala, J.; Nieminen, T.; Aalto, P. P.; Merkel, M.; Wiedensohler, A.; Kulmala, M.; Petäjä, T.; Hämeri, K.

    2015-12-01

    Air ion concentrations influence new particle formation and consequently the global aerosol as potential cloud condensation nuclei. We aimed to evaluate air ion concentrations and characteristics of new particle formation events (NPF) in the megacity of Paris, France, within the MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric Pollution and climate effects, and Integrated tools for assessment and mitigation) project. We measured air ion number size distributions (0.8-42 nm) with an air ion spectrometer and fine particle number concentrations (> 6 nm) with a twin differential mobility particle sizer in an urban site of Paris between 26 June 2009 and 4 October 2010. Air ions were size classified as small (0.8-2 nm), intermediate (2-7 nm), and large (7-20 nm). The median concentrations of small and large ions were 670 and 680 cm-3, respectively, (sum of positive and negative polarities), whereas the median concentration of intermediate ions was only 20 cm-3, as these ions were mostly present during new particle formation bursts, i.e. when gas-to-particle conversion produced fresh aerosol particles from gas phase precursors. During peaks in traffic-related particle number, the concentrations of small and intermediate ions decreased, whereas the concentrations of large ions increased. Seasonal variations affected the ion population differently, with respect to their size and polarity. NPF was observed in 13 % of the days, being most frequent in spring and late summer (April, May, July, and August). The results also suggest that NPF was favoured on the weekends in comparison to workdays, likely due to the lower levels of condensation sinks in the mornings of weekends (CS weekdays 09:00: 18 × 10-3 s-1; CS weekend 09:00: 8 × 10-3 s-1). The median growth rates (GR) of ions during the NPF events varied between 3 and 7 nm h-1, increasing with the ion size and being higher on workdays than on weekends for intermediate and large ions. The median GR of

  17. Air radon concentration decrease in a waste water treatment plant.

    PubMed

    Juste, B; Ortiz, J; Verdú, G; Martorell, S

    2015-06-01

    (222)Rn is a naturally occurring gas created from the decay of (226)Ra. The long-term health risk of breathing radon is lung cancer. One particular place where indoor radon concentrations can exceed national guidelines is in wastewater treatment plants (WWTPs) where treatment processes may contribute to ambient airborne concentrations. The aim of this paper was to study the radon concentration decrease after the application of corrective measures in a Spanish WWTP. According to first measures, air radon concentration exceeded International Commission Radiologica1 Protection (ICRP) normative (recommends intervention between 400 and 1000 Bq m(-3)). Therefore, the WWTP improved mechanical forced ventilation to lower occupational exposure. This measure allowed to increase the administrative controls, since the limitation of workers access to the plant changed from 2 h d(-1) (considering a maximum permissible dose of 20 mSv y(-1) averaged over 5 y) to 7 h d(-1).

  18. Air radon concentration decrease in a waste water treatment plant.

    PubMed

    Juste, B; Ortiz, J; Verdú, G; Martorell, S

    2015-06-01

    (222)Rn is a naturally occurring gas created from the decay of (226)Ra. The long-term health risk of breathing radon is lung cancer. One particular place where indoor radon concentrations can exceed national guidelines is in wastewater treatment plants (WWTPs) where treatment processes may contribute to ambient airborne concentrations. The aim of this paper was to study the radon concentration decrease after the application of corrective measures in a Spanish WWTP. According to first measures, air radon concentration exceeded International Commission Radiologica1 Protection (ICRP) normative (recommends intervention between 400 and 1000 Bq m(-3)). Therefore, the WWTP improved mechanical forced ventilation to lower occupational exposure. This measure allowed to increase the administrative controls, since the limitation of workers access to the plant changed from 2 h d(-1) (considering a maximum permissible dose of 20 mSv y(-1) averaged over 5 y) to 7 h d(-1). PMID:25971342

  19. Fate of Alicyclobacillus spp. in enrichment broth and in juice concentrates.

    PubMed

    Oteiza, Juan Martin; Soto, Silvina; Alvarenga, Verônica O; Sant'Ana, Anderson S; Gianuzzi, Leda

    2015-10-01

    In this study, the fate of Alicyclobacillus acidoterrestris spores in different types of juice concentrates stored under different conditions was investigated. In addition, the impact of dilution procedures during the enrichment step for the detection of Alicyclobacillus in lemon juice concentrates was studied. Pear, red grape, mango, tangerine, carrot and lemon juice concentrates (50-69.4°Brix, pH1.7-4.3) were inoculated with A. acidoterrestris spores (10(3) spore/mL) and stored at 4 °C and 20 °C, after which the spores were counted at 0, 2, 5, 9, 17, 21, 28, 36, 43, and 50 days. No significant differences in the number of Alicyclobacillus spores were observed at storage temperatures of 4 °C and 20 °C (p>0.05). The results also indicated that the number of spores of A. acidoterrestris remained stable in all types of juice concentrates during the storage period, except in lemon juice concentrate. In lemon juice concentrate, a decline in A. acidoterrestris spore populations of 0.3-0.8 log CFU/mL was observed within 5-10 days of storage. The decline in A. acidoterrestris spore populations was more pronounced in cloudy lemon juice concentrate, which contained higher concentrations of flavonoids (mainly eriocitrin and hesperidin) than clarified lemon juice concentrate. It was also found that dilution of lemon juice concentrate samples in the proportion of 1:19 allowed the germination of A. acidoterrestris spores and the growth of populations of up to 10(7) CFU/mL. In contrast, the proportion (1:9) recommended in internationally recognized methods led to a reduction in the population of this microorganism that would yield false negative results. Data presented in this study demonstrated that Alicyclobacillus spores remain stable in most juice concentrates during storage, but that natural antimicrobial compounds present in some of them may decrease spore counts and inhibit their recovery by detection procedures.

  20. [Effects of free-air CO2 enrichment (FACE) on yield formation in rice (Oryza sativa)].

    PubMed

    Huang, Jianye; Yang, Hongjian; Dong, Guichun; Wang, Yulong; Zhu, Jianguo; Yang, Lianxian; Shan, Yuhua

    2002-10-01

    Effect of Free-Air CO2 enrichment (FACE, 200 mumol.mol-1 higher than CK) on rice yield and its components under field condition were studied with a Japonica variety 99-15. Results showed that FACE treatment had no obvious effect on plant height and number of leaves on main stem, but could quicken growth process of rice, shorten the whole growth duration. Increment of nitrogen application rate could weaken the effect of FACE on whole growth duration. The number of tillers and panicles, and fulfilled-grain percentage increased significantly under FACE treatment, whereas spikelets per panicle decreased. FACE treatment could significantly increase grain yield of rice, especially when higher rate of nitrogen fertilizer was applied. Increasing spikelets per panicle and spikelets per unit area under FACE treatment would result in marked increment of rice yield. Increasing nitrogen application rate was an important approach to increase spikelets per panicle and spikelets per unit area under FACE treatment.

  1. Synthesis of silicalite-poly(furfuryl alcohol) composite membranes for oxygen enrichment from air

    PubMed Central

    2011-01-01

    Silicalite-poly(furfuryl alcohol) [PFA] composite membranes were prepared by solution casting of silicalite-furfuryl alcohol [FA] suspension on a porous polysulfone substrate and subsequent in situ polymerization of FA. X-ray diffraction, nitrogen sorption, thermogravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to characterize silicalite nanocrystals and silicalite-PFA composite membranes. The silicalite-PFA composite membrane with 20 wt.% silicalite loading exhibits good oxygen/nitrogen selectivity (4.15) and high oxygen permeability (1,132.6 Barrers) at 50°C. Silicalite-PFA composite membranes are promising for the production of oxygen-enriched air for various applications. PMID:22209012

  2. A PRINCIPAL COMPONENT ANALYSIS OF THE CLEAN AIR STATUS AND TRENDS NETWORK (CASTNET) AIR CONCENTRATION DATA

    EPA Science Inventory

    The spatial and temporal variability of ambient air concentrations of SO2, SO42-, NO3, HNO3, and NH4+ obtained from EPA's CASTNet was examined using an objective, statistically based technique...

  3. BOREAS TGB-7 Ambient Air Herbicide and Organochlorine Concentration Data

    NASA Technical Reports Server (NTRS)

    Waite, Don; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB)-7 team measured the concentration and flux of several agricultural pesticides in air, rainwater, and dry deposition samples in order to determine the associated yearly deposition rates. This data set contains information on the ambient air concentration of seven herbicides [2,4- dichlorophenoxyacidic_acid (2,4-D), bromoxynil, dicamb, 2-methyl-4-chlorophenoxyacetic acid (MCPA), triallate, trifluralin, and diclop-methyl] known to appear in the atmosphere of the Canadian prairies. Also, the concentration of three herbicides (atrazine, alachlor, and metolachlor), two groups of insecticides (lindane and breakdown products and dichloro-diphenyl-trichloroethane (DDT) and breakdown products), and several polychlorinated biphenyls commonly used in the central United States was measured. All of these chemicals are reported, in the literature, to be transported in the atmosphere. Many have been reported to occur in boreal and arctic food chains. The sampling was carried out from 16-Jun to 13-Aug-1993 and 04-May to 20-Jul-1994 at the BOREAS site in the Prince Albert National Park (Waskesiu). The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884).

  4. Effect of backyard burning on dioxin deposition and air concentrations.

    PubMed

    Wevers, M; De Fré, R; Desmedt, M

    2004-03-01

    The influence from open burning of garden and household waste on locally measured dioxin deposition and air concentrations was evaluated in three sets of experiments: the combustion of garden waste in barrels and in open fires, and the incineration of household waste in an empty oil drum. Each set was composed of eight individual experiments over 4 h. Deposition gauges were located 20 m NE, SE, SW and NW with respect to the source and on a background location at 400 m SW. Air samples were taken in the plume with a medium volume sampler equipped with a quartz filter and a polyurethane plug. The results illustrate deposition increments in the wind direction at a distance of 20 m from the source of 0.8 pg TEQ/m2 day for garden waste and 2.5 pg TEQ/m2 day for household waste. Concentrations in the plume were increased by 160-580 fg TEQ/m3 over a period of 12 and 31 h respectively. Expressed at a reference CO2 concentration of 9% this corresponds with a range from 0.8 to 3.6 ng TEQ/m3, which is comparable with a poorly controlled MSWI. Emission factors in the order of magnitude of 4.5 ng TEQ/kg combusted garden waste and 35 ng TEQ/kg burned municipal waste were determined.

  5. CO₂ enrichment can produce high red leaf lettuce yield while increasing most flavonoid glycoside and some caffeic acid derivative concentrations.

    PubMed

    Becker, Christine; Kläring, Hans-Peter

    2016-05-15

    Carbon dioxide (CO2) enrichment is a common practice in greenhouses to increase crop yields up to 30%. Yet, reports on the effect on foliar phenolic compounds vary. We studied the effect on two red leaf lettuce cultivars, grown for 25 days in growth chambers at CO2 concentrations of 200 or 1,000 ppm, with some plants exchanged between treatments after 11 days. As expected, head mass increased with higher CO2 concentration. Regression analysis, corrected for head mass, showed increased concentrations of most flavonoid glycosides at high CO2 concentrations while only some caffeic acid derivatives were increased, and not uniformly in both cultivars. Sugar concentrations increased with CO2 concentration. Generally, conditions in the 10 days before harvest determined concentrations. We suspect that phenolic compounds were mainly accumulated because plenty of precursors were available. The results indicate that CO2 enrichment can result in high yields of red leaf lettuce rich in phenolic compounds.

  6. CO₂ enrichment can produce high red leaf lettuce yield while increasing most flavonoid glycoside and some caffeic acid derivative concentrations.

    PubMed

    Becker, Christine; Kläring, Hans-Peter

    2016-05-15

    Carbon dioxide (CO2) enrichment is a common practice in greenhouses to increase crop yields up to 30%. Yet, reports on the effect on foliar phenolic compounds vary. We studied the effect on two red leaf lettuce cultivars, grown for 25 days in growth chambers at CO2 concentrations of 200 or 1,000 ppm, with some plants exchanged between treatments after 11 days. As expected, head mass increased with higher CO2 concentration. Regression analysis, corrected for head mass, showed increased concentrations of most flavonoid glycosides at high CO2 concentrations while only some caffeic acid derivatives were increased, and not uniformly in both cultivars. Sugar concentrations increased with CO2 concentration. Generally, conditions in the 10 days before harvest determined concentrations. We suspect that phenolic compounds were mainly accumulated because plenty of precursors were available. The results indicate that CO2 enrichment can result in high yields of red leaf lettuce rich in phenolic compounds. PMID:26776031

  7. Microclimatic performance of a free-air warming and CO₂ enrichment experiment in windy Wyoming, USA

    SciTech Connect

    LeCain, Daniel; Smith, David; Morgan, Jack; Kimball, Bruce A.; Pendall, Elise; Miglietta, Franco; Liang, Wenju

    2015-02-06

    In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO₂) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO₂ enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night) but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms⁻¹ average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO₂ had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO₂. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming for much

  8. Microclimatic performance of a free-air warming and CO₂ enrichment experiment in windy Wyoming, USA

    DOE PAGES

    LeCain, Daniel; Smith, David; Morgan, Jack; Kimball, Bruce A.; Pendall, Elise; Miglietta, Franco; Liang, Wenju

    2015-02-06

    In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO₂) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO₂ enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night)more » but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms⁻¹ average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO₂ had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO₂. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming

  9. Indoor air-assessment: Indoor concentrations of environmental carcinogens

    SciTech Connect

    Gold, K.W.; Naugle, D.F.; Berry, M.A.

    1991-01-01

    In the report, indoor concentration data are presented for the following general categories of air pollutants: radon-222, environmental tobacco smoke (ETS), asbestos, gas phase organic compounds, formaldehyde, polycyclic aromatic hydrocarbons (PAH), pesticides, and inorganic compounds. These pollutants are either known or suspect carcinogens (i.e., radon-222, asbestos) or more complex mixtures or classes of compounds which contain known or suspect carcinogens. Concentration data for individual carcinogenic compounds in complex mixtures are usually far from complete. The data presented for complex mixtures often include compounds which are not carcinogenic or for which data are insufficient to evaluate carcinogenicity. Their inclusion is justified, however, by the possibility that further work may show them to be carcinogens, cocarcinogens, initiators or promotors, or that they may be employed as markers (e.g., nicotine, acrolein) for the estimation of exposure to complex mixtures.

  10. Air Pollution in China: Mapping of Concentrations and Sources

    PubMed Central

    Rohde, Robert A.; Muller, Richard A.

    2015-01-01

    China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread across northern and central China and are not limited to major cities or geologic basins. Sources of pollution are widespread, but are particularly intense in a northeast corridor that extends from near Shanghai to north of Beijing. During our analysis period, 92% of the population of China experienced >120 hours of unhealthy air (US EPA standard), and 38% experienced average concentrations that were unhealthy. China’s population-weighted average exposure to PM2.5 was 52 μg/m3. The observed air pollution is calculated to contribute to 1.6 million deaths/year in China [0.7–2.2 million deaths/year at 95% confidence], roughly 17% of all deaths in China. PMID:26291610

  11. Air Pollution in China: Mapping of Concentrations and Sources.

    PubMed

    Rohde, Robert A; Muller, Richard A

    2015-01-01

    China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread across northern and central China and are not limited to major cities or geologic basins. Sources of pollution are widespread, but are particularly intense in a northeast corridor that extends from near Shanghai to north of Beijing. During our analysis period, 92% of the population of China experienced >120 hours of unhealthy air (US EPA standard), and 38% experienced average concentrations that were unhealthy. China's population-weighted average exposure to PM2.5 was 52 μg/m3. The observed air pollution is calculated to contribute to 1.6 million deaths/year in China [0.7-2.2 million deaths/year at 95% confidence], roughly 17% of all deaths in China. PMID:26291610

  12. Concentrations of air toxics in motor vehicle-dominated environments.

    PubMed

    Fujita, Eric M; Campbell, David E; Zielinska, Barbara; Arnott, William P; Chow, Judith C

    2011-02-01

    We at the Desert Research Institute (DRI*) measured volatile organic compounds (VOCs), including several mobile-source air toxics (MSATs), particulate matter with a mass mean aerodynamic diameter < or = 2.5 pm (PM2.5), black carbon (BC), nitrogen oxides (NOx), particulate matter (PM), and carbon monoxide (CO) on highways in Los Angeles County during summer and fall 2004, to characterize the diurnal and seasonal variations in measured concentrations related to volume and mix of traffic. Concentrations of on-road pollutants were then compared to corresponding measurements at fixed monitoring sites. The on-road concentrations of CO and MSATs were higher in the morning under stable atmospheric conditions and during periods of higher traffic volumes. In contrast, BC concentrations, measured as particulate light absorption, were higher on truck routes during the midday sampling periods despite more unstable atmospheric conditions. Compared to the measurements at the three near-road sites, the 1-hour averages of on-road BC concentrations were as much as an order of magnitude higher. The peak 1-minute average concentrations were two orders of magnitude higher for BC and were between two and six times higher for PM2.5 mass. The on-road concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX) during the summer were 3.5 +/- 0.7 and 1.2 +/- 0.6 times higher during morning and afternoon commuting periods, respectively, compared to annual average 24-hour concentrations measured at air toxic monitoring network sites. These ratios were higher during the fall, with smaller diurnal differences (4.8 +/- 0.7 and 3.9 +/- 0.6 for morning and afternoon commuting periods, respectively). Ratios similar to those for BTEX were obtained for 1,3-butadiene (BD) and styrene. On-road concentrations of formaldehyde and acetaldehyde were up to two times higher than at air toxics monitoring sites, with fall ratios slightly higher than summer ratios. Chemical mass balance (CMB) receptor

  13. Sooting Limits Of Diffusion Flames With Oxygen-Enriched Air And Diluted Fuel

    NASA Technical Reports Server (NTRS)

    Sunderland, P. B.; Urban, D. L.; Stocker, D. P.; Chao, B. H.; Axelbaum, R. L.

    2003-01-01

    Oxygen-enhanced combustion permits certain benefits and flexibility that are not otherwise available in the design of practical combustors, as discussed by Baukal. The cost of pure and enriched oxygen has declined to the point that oxygen-enhanced combustion is preferable to combustion in air for many applications. Carbon sequestration is greatly facilitated by oxygen enrichment because nitrogen can be eliminated from the product stream. For example, when natural gas (or natural gas diluted with CO2) is burned in pure oxygen, the only significant products are water and CO2. Oxygen-enhanced combustion also has important implications for soot formation, as explored in this work. We propose that soot inception in nonpremixed flames requires a region where C/O ratio, temperature, and residence time are above certain critical values. Soot does not form at low temperatures, with the threshold in nonpremixed flames ranging from about 1250-1650 K, a temperature referred to here as the critical temperature for soot inception, Tc. Soot inception also can be suppressed when residence time is short (equivalently, when the strain rate in counterflow flames is high). Soot induction times of 0.8-15 ms were reported by Tesner and Shurupov for acetylene/nitrogen mixtures at 1473 K. Burner stabilized spherical microgravity flames are employed in this work for two main reasons. First, this configuration offers unrestricted control over convection direction. Second, in steady state these flames are strain-free and thus can yield intrinsic sooting limits in diffusion flames, similar to the way past work in premixed flames has provided intrinsic values of C/O ratio associated with soot inception limits.

  14. Job Enrichment: Evaluation with Implications for Air Force Job Redesign. Interim Report, 1 January 1975-30 April 1977.

    ERIC Educational Resources Information Center

    Watson, Thomas W.; Zumbro, Patrick A.

    The main text of this report consists of a review and evaluation of job enrichment as an approach to job redesign, with implications for Air Force research and application. In addition, two appendixes are included: the first, a supplemental historical discussion; the second, a ninety-six-item annotated bibliography. Specific objectives are to…

  15. Potential benefits of oxygen-enriched intake air in a vehicle powered by a spark-ignition engine

    SciTech Connect

    Ng, H.K.; Sekar, R.R.

    1994-04-01

    A production vehicle powered by a spark-ignition engine (3.1-L Chevrolet Lumina, model year 1990) was tested. The test used oxygen-enriched intake air containing 25 and 28% oxygen by volume to determine (1) if the vehicle would run without difficulties and (2) if emissions benefits would result. Standard Federal Test Procedure (FTP) emissions test cycles were run satisfactorily. Test results of catalytic converter-out emissions (emissions out of the converter) showed that both carbon monoxide and hydrocarbons were reduced significantly in all three phases of the emissions test cycle. Test results of engine-out emissions (emissions straight out of the engine, with the converter removed) showed that carbon monoxide was significantly reduced in the cold phase. All emission test results were compared with those for normal air (21% oxygen). The catalytic converter also had an improved carbon monoxide conversion efficiency under the oxygen-enriched-air conditions. Detailed results of hydrocarbon speciation indicated large reductions in 1,3-butadiene, formaldehyde, acetaldehyde, and benzene from the engine with the oxygen-enriched air. Catalytic converter-out ozone was reduced by 60% with 25%-oxygen-content air. Although NO{sub x} emissions increased significantly, both for engine-out and catalytic converter-out emissions, we anticipate that they can be ameliorated in the near future with new control technologies. The automotive industry currently is developing exhaust-gas control technologies for an oxidizing environment; these technologies should reduce NO{sub x} emissions more efficiently in vehicles that use oxygen-enriched intake air. On the basis of estimates made from current data, several production vehicles that had low NO{sub x} emissions could meet the 2004 Tier II emissions standards with 25%-oxygen-content air.

  16. CO sub 2 enrichment of tomatoes: Relationship of foliar stress symptoms to starch concentrations and carbon exchange rates

    SciTech Connect

    Tripp, K.; Peet, M.; Pharr, D.M.; Willits, D. )

    1990-05-01

    CO{sub 2} enrichment of tomatoes results in a seasonally progressive downrolling, chlorosis and purpling of foliage, beginning with the older leaves, but eventually including the entire plant. This deformation has generally been attributed to excess starch. In a comparison of 2 cultivars given CO{sub 2} enrichment and treatments modifying source/sink ratios (fruit pruning, high night temperatures, decreased rooting volume), however, changes in deformation could not be related to changes in foliar starch concentrations. While CO{sub 2} enriched plants had higher foliar starch and greater foliar deformation, deformation increased over the season while starch decreased. Carbon exchange rates (CER) were low in lower canopy leaves, whether deformed or not. CO{sub 2} enrichment resulted in only slightly higher photosynthetic rates. Over all treatments and sampling data there was no relationship between foliar deformation and CER.

  17. GEMAS - Tin and Tungsten: possible sources of enriched concentrations in soils in European countries

    NASA Astrophysics Data System (ADS)

    João Batista, Maria; Filipe, Augusto; Reimann, Clemens

    2014-05-01

    southern soils and SiO2 is higher in loess sediments region, in the North German-Poland basin and in the Paris basin. Organic matter may immobilise these metals and silica content influences metallic elements concentrations in soils. Natural processes of soil development, land management of agricultural soils and population density all together may be responsible for higher concentrations of W in the soils of Netherlands Germany, Belgium, Switzerland and northeast France which seems not related with Sn-W mineral provinces. Tin and tungsten are enriched in the Precambrian shields compared to the Caledonian shields soils in the northern countries, although in northern countries climatic conditions may play the most important role in these elements concentrations. Tin and tungsten and tin or tungsten alone or in association of precious metals, copper, uranium, niobium, beryllium, titanium altogether were extracted in 650 small or median size mines in Portugal. Except tin in Neves Corvo mine of the Iberian Pyrite Belt the rest of these mines occurred in the Variscides granitic intrusions region. Tin and tungsten concentrations are therefore well reflected in the northern Portugal soils. At the GEMAS density of sampling pollution and local natural phenomena are not reflected in mapping but this important province is well delimited.

  18. The effect of free air carbon dioxide enrichment and nitrogen fertilisation on the chemical composition and nutritional value of wheat and barley grain.

    PubMed

    Wroblewitz, Stefanie; Hüther, Liane; Manderscheid, Remy; Weigel, Hans-Joachim; Wätzig, Hermann; Dänicke, Sven

    2013-08-01

    A rising atmospheric CO2 concentration might influence the nutrient composition of feedstuffs and consequently the nutritional value for livestock. The present study investigates the effects of atmospheric CO2 enrichment on the chemical composition and nutritional value of winter wheat cv. "Batis" and winter barley cv. "Theresa". Both cereals were grown at two different atmospheric CO2 concentrations (ambient CO2 [AMBI]: 380 ppm and enriched CO2 [free air carbon dioxide enrichment, FACE]: 550 ppm) for two growing seasons. The influence of two different nitrogen (N) fertilisation levels (adequate N supply [N100] and nearly 50% of adequate N supply [N50]) were studied as well. A significant effect was observed for the crude protein content, which declined at FACE condition in a range of 8-16 g kg(-1) in wheat and of 10-20 g kg(-1) in barley. A reduced N fertilisation level resulted in a strong reduction of crude protein concentration in both cereal species. In wheat, a decrease in N supply significantly enhanced the concentration of starch and crude fibre. In barley, only the concentration of fructose increased under FACE condition and reduced N fertilisation. The FACE did not have major effects on the concentrations of minerals, while the influence of N fertilisation was different for both cereals. Whereas no effects could be observed for barley, a reduced N supply caused a significant reduction in concentrations of zinc, manganese and iron in wheat. Furthermore, an undirected effect of atmospheric CO2 and N fertilisation levels were found for the amino acid concentrations. Based on these results, future scenarios of climate change would have an impact on the nutritional value of cereal grains.

  19. Differences in nitrite-oxidizing communities and kinetics in a brackish environment after enrichment at low and high nitrite concentrations.

    PubMed

    Tangkitjawisut, Wipasanee; Limpiyakorn, Tawan; Powtongsook, Sorawit; Pornkulwat, Preeyaporn; Suwannasilp, Benjaporn Boonchayaanant

    2016-04-01

    Nitrite accumulation in shrimp ponds can pose serious adverse effects to shrimp production and the environment. This study aims to develop an effective process for the enrichment of ready-to-use nitrite-oxidizing bacteria (NOB) inocula that would be appropriate for nitrite removal in brackish shrimp ponds. To achieve this objective, the effects of nitrite concentrations on NOB communities and nitrite oxidation kinetics in a brackish environment were investigated. Moving-bed biofilm sequencing batch reactors and continuous moving-bed biofilm reactors were used for the enrichment of NOB at various nitrite concentrations, using sediment from brackish shrimp ponds as seed inoculum. The results from NOB population analysis with quantitative polymerase chain reaction (qPCR) show that only Nitrospira were detected in the sediment from the shrimp ponds. After the enrichment, both Nitrospira and Nitrobacter coexisted in the reactors controlling effluent nitrite at 0.1 and 0.5 mg-NO2(-)-N/L. On the other hand, in the reactors controlling effluent nitrite at 3, 20, and 100 mg-NO2(-)-N/L, Nitrobacter outcompeted Nitrospira in many orders of magnitude. The half saturation coefficients (Ks) for nitrite oxidation of the enrichments at low nitrite concentrations (0.1 and 0.5 mg-NO2(-)-N/L) were in the range of 0.71-0.98 mg-NO2(-)-N/L. In contrast, the K(s) values of NOB enriched at high nitrite concentrations (3, 20, and 100 mg-NO2(-)-N/L) were much higher (8.36-12.20 mg-NO2(-)-N/L). The results suggest that the selection of nitrite concentrations for the enrichment of NOB inocula can significantly influence NOB populations and kinetics, which could affect the effectiveness of their applications in brackish shrimp ponds.

  20. Differences in nitrite-oxidizing communities and kinetics in a brackish environment after enrichment at low and high nitrite concentrations.

    PubMed

    Tangkitjawisut, Wipasanee; Limpiyakorn, Tawan; Powtongsook, Sorawit; Pornkulwat, Preeyaporn; Suwannasilp, Benjaporn Boonchayaanant

    2016-04-01

    Nitrite accumulation in shrimp ponds can pose serious adverse effects to shrimp production and the environment. This study aims to develop an effective process for the enrichment of ready-to-use nitrite-oxidizing bacteria (NOB) inocula that would be appropriate for nitrite removal in brackish shrimp ponds. To achieve this objective, the effects of nitrite concentrations on NOB communities and nitrite oxidation kinetics in a brackish environment were investigated. Moving-bed biofilm sequencing batch reactors and continuous moving-bed biofilm reactors were used for the enrichment of NOB at various nitrite concentrations, using sediment from brackish shrimp ponds as seed inoculum. The results from NOB population analysis with quantitative polymerase chain reaction (qPCR) show that only Nitrospira were detected in the sediment from the shrimp ponds. After the enrichment, both Nitrospira and Nitrobacter coexisted in the reactors controlling effluent nitrite at 0.1 and 0.5 mg-NO2(-)-N/L. On the other hand, in the reactors controlling effluent nitrite at 3, 20, and 100 mg-NO2(-)-N/L, Nitrobacter outcompeted Nitrospira in many orders of magnitude. The half saturation coefficients (Ks) for nitrite oxidation of the enrichments at low nitrite concentrations (0.1 and 0.5 mg-NO2(-)-N/L) were in the range of 0.71-0.98 mg-NO2(-)-N/L. In contrast, the K(s) values of NOB enriched at high nitrite concentrations (3, 20, and 100 mg-NO2(-)-N/L) were much higher (8.36-12.20 mg-NO2(-)-N/L). The results suggest that the selection of nitrite concentrations for the enrichment of NOB inocula can significantly influence NOB populations and kinetics, which could affect the effectiveness of their applications in brackish shrimp ponds. PMID:27090693

  1. Biodegradation of high concentrations of halomethanes by a fermentative enrichment culture

    PubMed Central

    2014-01-01

    A fermentative enrichment culture (designated DHM-1) that grows on corn syrup was evaluated for its ability to cometabolically biodegrade high concentrations of chloroform (CF), carbon tetrachloride (CT), and trichlorofluoromethane (CFC-11). When provided with corn syrup and vitamin B12 (0.03 mol B12 per mol CF), DHM-1 grew and biodegraded up to 2,000 mg/L of CF in 180 days, with only minor transient accumulation of dichloromethane and chloromethane. CT (15 mg/L) and CFC-11 (25 mg/L) were also biodegraded without significant accumulation of halomethane daughter products. The rate of CF biodegradation followed a Michaelis-Menten-like pattern with respect to the B12 concentration; one-half the maximum rate (66 mg CF/L/d) occurred at 0.005 mol B12 per mol CF. DHM-1 was able to biodegrade 500 mg/L of CF at an inoculum level as low as 10−8 mg protein/L. The highest rate of CF biodegradation occurred at pH 7.7; activity decreased substantially below pH 6.0. DHM-1 biodegraded mixtures of CT, CFC-11, and CF, although CFC-11 inhibited CF biodegradation. Evidence for compete defluorination of CFC-11 was obtained based on a fluoride mass balance. Overall, the results suggest that DHM-1 may be effective for bioaugmentation in source zones contaminated with thousands of milligrams per liter of CF and tens of milligrams per liter of CT and CFC-11. PMID:25401061

  2. [Effects of free-air CO2 enrichment (FACE) on yield formation of wheat].

    PubMed

    Ynag, Lian-xin; Li, Shi-feng; Wang, Yu-long; Huang, Jian-ye; Yang, Hong-jian; Dong, Gui-chun; Zhu, Jian-guo; Liu, Gang

    2007-01-01

    To investigate the effects of predicted higher CO2 levels on the growth duration, plant height, yield, and yield components of wheat (Triticum aestivum L.), a free-air CO2 enrichment (FACE) experiment with weak gluten variety Ningmai 9 was conducted at Anzhen of Wuxi in Jiangsu Province in 2001-2002 and 2002-2003 growth seasons. The target [CO2] in FACE plots was 200 microl x L(-1) above that in ambient air. Three levels of N were supplied, i.e., 90 kg x hm(-2) (2001-2002) and 125 kg x hm(-2)(2002-2003) (low level, LN), 180 kg x hm(-2) 2002-2003) (medium level, MN), and 250 kg x hm(-2)(high level, HN). The durations from sowing to heading and from heading to maturity and the whole growth period of wheat in FACE plots shortened 1.3 , 1.3 and 2.6 days, respectively, compared with the control. FACE increased the plant height (+4.0% significantly, due to the increases of panicle length and of the first and second internode lengths. FACE also greatly increased the grain yield by an average of 24.6%. Across the two years, there was a positive [CO2] x N interaction for grain yield, with a yield increase of 15.2%, 21.4% and 35.4% at LN, MN and HN, respectively. The ears per square meter in FACE plots was increased by an average of 17.8% mainly due to the increase of maximum tiller number per unit ground area rather than that of the percentage of productive tiller (panicle bearing). In addition, FACE increased the grain number per ear (+2.9% and the individual grain mass (+4.8%).

  3. The O₂-enriched air gasification of coal, plastics and wood in a fluidized bed reactor.

    PubMed

    Mastellone, Maria Laura; Zaccariello, Lucio; Santoro, Donato; Arena, Umberto

    2012-04-01

    The effect of oxygen-enriched air during fluidized bed co-gasification of a mixture of coal, plastics and wood has been investigated. The main components of the obtained syngas were measured by means of on-line analyzers and a gas chromatograph while those of the condensate phase were off-line analysed by means of a gas chromatography-mass spectrometer (GC-MS). The characterization of condensate phase as well as that of the water used as scrubbing medium completed the performed diagnostics. The experimental results were further elaborated in order to provide material and substances flow analyses inside the plant boundaries. These analyses allowed to obtain the main substance distribution between solid, gaseous and condensate phases and to estimate the conversion efficiency of carbon and hydrogen but also to easily visualise the waste streams produced by the process. The process performance was then evaluated on the basis of parameters related to the conversion efficiency of fuels into valuable products (i.e. by considering tar and particulate as process losses) as well as those related to the energy recovery. PMID:21993077

  4. The O₂-enriched air gasification of coal, plastics and wood in a fluidized bed reactor.

    PubMed

    Mastellone, Maria Laura; Zaccariello, Lucio; Santoro, Donato; Arena, Umberto

    2012-04-01

    The effect of oxygen-enriched air during fluidized bed co-gasification of a mixture of coal, plastics and wood has been investigated. The main components of the obtained syngas were measured by means of on-line analyzers and a gas chromatograph while those of the condensate phase were off-line analysed by means of a gas chromatography-mass spectrometer (GC-MS). The characterization of condensate phase as well as that of the water used as scrubbing medium completed the performed diagnostics. The experimental results were further elaborated in order to provide material and substances flow analyses inside the plant boundaries. These analyses allowed to obtain the main substance distribution between solid, gaseous and condensate phases and to estimate the conversion efficiency of carbon and hydrogen but also to easily visualise the waste streams produced by the process. The process performance was then evaluated on the basis of parameters related to the conversion efficiency of fuels into valuable products (i.e. by considering tar and particulate as process losses) as well as those related to the energy recovery.

  5. Simulation of climate change impacts on grain sorghum production grown under free air CO2 enrichment

    NASA Astrophysics Data System (ADS)

    Fu, Tongcheng; Ko, Jonghan; Wall, Gerard W.; Pinter, Paul J.; Kimball, Bruce A.; Ottman, Michael J.; Kim, Han-Yong

    2016-07-01

    Potential impacts of climate change on grain sorghum (Sorghum bicolor) productivity were investigated using the CERES-sorghum model in the Decision Support System for Agrotechnology Transfer v4.5. The model was first calibrated for a sorghum cultivar grown in a free air CO2 enrichment experiment at the University of Arizona, Maricopa, Arizona, USA in 1998. The model was then validated with an independent dataset collected in 1999. The simulated grain yield, growth, and soil water of sorghum for the both years were in statistical agreement with the corresponding measurements, respectively. Neither simulated nor measured yields responded to elevated CO2, but both were sensitive to water supply. The validated model was then applied to simulate possible effects of climate change on sorghum grain yield and water use efficiency in western North America for the years 2080-2100. The projected CO2 fertilizer effect on grain yield was dominated by the adverse effect of projected temperature increases. Therefore, temperature appears to be a dominant driver of the global climate change influencing future sorghum productivity. These results suggest that an increase in water demand for sorghum production should be anticipated in a future high-CO2 world.

  6. Model-data synthesis for the next generation of forest free-air CO2 enrichment (FACE) experiments.

    PubMed

    Norby, Richard J; De Kauwe, Martin G; Domingues, Tomas F; Duursma, Remko A; Ellsworth, David S; Goll, Daniel S; Lapola, David M; Luus, Kristina A; MacKenzie, A Rob; Medlyn, Belinda E; Pavlick, Ryan; Rammig, Anja; Smith, Benjamin; Thomas, Rick; Thonicke, Kirsten; Walker, Anthony P; Yang, Xiaojuan; Zaehle, Sönke

    2016-01-01

    The first generation of forest free-air CO2 enrichment (FACE) experiments has successfully provided deeper understanding about how forests respond to an increasing CO2 concentration in the atmosphere. Located in aggrading stands in the temperate zone, they have provided a strong foundation for testing critical assumptions in terrestrial biosphere models that are being used to project future interactions between forest productivity and the atmosphere, despite the limited inference space of these experiments with regards to the range of global ecosystems. Now, a new generation of FACE experiments in mature forests in different biomes and over a wide range of climate space and biodiversity will significantly expand the inference space. These new experiments are: EucFACE in a mature Eucalyptus stand on highly weathered soil in subtropical Australia; AmazonFACE in a highly diverse, primary rainforest in Brazil; BIFoR-FACE in a 150-yr-old deciduous woodland stand in central England; and SwedFACE proposed in a hemiboreal, Pinus sylvestris stand in Sweden. We now have a unique opportunity to initiate a model-data interaction as an integral part of experimental design and to address a set of cross-site science questions on topics including responses of mature forests; interactions with temperature, water stress, and phosphorus limitation; and the influence of biodiversity. PMID:26249015

  7. Model-data synthesis for the next generation of forest free-air CO2 enrichment (FACE) experiments.

    PubMed

    Norby, Richard J; De Kauwe, Martin G; Domingues, Tomas F; Duursma, Remko A; Ellsworth, David S; Goll, Daniel S; Lapola, David M; Luus, Kristina A; MacKenzie, A Rob; Medlyn, Belinda E; Pavlick, Ryan; Rammig, Anja; Smith, Benjamin; Thomas, Rick; Thonicke, Kirsten; Walker, Anthony P; Yang, Xiaojuan; Zaehle, Sönke

    2016-01-01

    The first generation of forest free-air CO2 enrichment (FACE) experiments has successfully provided deeper understanding about how forests respond to an increasing CO2 concentration in the atmosphere. Located in aggrading stands in the temperate zone, they have provided a strong foundation for testing critical assumptions in terrestrial biosphere models that are being used to project future interactions between forest productivity and the atmosphere, despite the limited inference space of these experiments with regards to the range of global ecosystems. Now, a new generation of FACE experiments in mature forests in different biomes and over a wide range of climate space and biodiversity will significantly expand the inference space. These new experiments are: EucFACE in a mature Eucalyptus stand on highly weathered soil in subtropical Australia; AmazonFACE in a highly diverse, primary rainforest in Brazil; BIFoR-FACE in a 150-yr-old deciduous woodland stand in central England; and SwedFACE proposed in a hemiboreal, Pinus sylvestris stand in Sweden. We now have a unique opportunity to initiate a model-data interaction as an integral part of experimental design and to address a set of cross-site science questions on topics including responses of mature forests; interactions with temperature, water stress, and phosphorus limitation; and the influence of biodiversity.

  8. Changes in soil C-isotopic composition in an agroecosystem under Free Air Carbon dioxide Enrichment (FACE) treatment during a crop rotation period.

    PubMed

    Giesemann, Anette

    2005-01-01

    FACE (Free Air Carbon dioxide Enrichment) has been used since 1999 to evaluate the effects of future atmospheric CO(2) concentrations on an arable crop agroecosystem. The experiment conducted at the Institute of Agroecology at the Federal Research Centre in Braunschweig consists of a typical local crop rotation of winter barley, a cover crop, sugar beet and winter wheat. The atmospheric CO2 concentration of ambient air is about 375 ppm with a delta13C value of -7 to -9 per thousand, and 550 ppm (delta13C value = -20.2 per thousand) during daylight hours in the rings fumigated with additional CO2. Thus, the surplus C can be traced in the agricultural system. Over the course of the first experimental period (3-year crop rotation period), the C-isotopic composition and the C concentration in soil were monitored monthly. Plant samples were analysed according to the relevant developmental stages of the crop under cultivation. A 13C depletion was observed in plant parts, as well as in soil samples from the FACE rings under CO2 enrichment, indicating that labelled C has reached both respective ecosystem compartments. Albeit farming management practice (especially ploughing) leads to a mixing of 'old' and 'new' C compounds throughout all soil horizons down to the end of the ploughing layer and resulted in a heterogeneous distribution of newly formed C compounds in the soil, isotope analysis of soil C reflected where the surplus C went.

  9. Catalytic wet air oxidation of high concentration pharmaceutical wastewater.

    PubMed

    Zhan, Wei; Wang, Xiaocong; Li, Daosheng; Ren, Yongzheng; Liu, Dongqi; Kang, Jianxiong

    2013-01-01

    In this study, we investigated the pretreatment of a high concentration pharmaceutical wastewater by catalytic wet air oxidation (CWAO) process. Different experiments were conducted to investigate the effects of the catalyst type, operating temperature, initial system pH, and oxygen partial pressure on the oxidation of the wastewater. Results show that the catalysts prepared by the co-precipitation method have better catalytic activity compared to others. Chemical oxygen demand (COD) conversion increased with the increase in temperature from 160 to 220 °C and decreased with the increase in pH. Moreover, the effect of the oxygen partial pressure on the COD conversion was significant only during the first 20 min of the reaction. Furthermore, the biodegradability of the wastewater improved greatly after CWAO, the ratio of BOD5/COD increased less than 0.1-0.75 when treated at 220 °C (BOD: biochemical oxygen demand). PMID:23676399

  10. Catalytic wet air oxidation of high concentration pharmaceutical wastewater.

    PubMed

    Zhan, Wei; Wang, Xiaocong; Li, Daosheng; Ren, Yongzheng; Liu, Dongqi; Kang, Jianxiong

    2013-01-01

    In this study, we investigated the pretreatment of a high concentration pharmaceutical wastewater by catalytic wet air oxidation (CWAO) process. Different experiments were conducted to investigate the effects of the catalyst type, operating temperature, initial system pH, and oxygen partial pressure on the oxidation of the wastewater. Results show that the catalysts prepared by the co-precipitation method have better catalytic activity compared to others. Chemical oxygen demand (COD) conversion increased with the increase in temperature from 160 to 220 °C and decreased with the increase in pH. Moreover, the effect of the oxygen partial pressure on the COD conversion was significant only during the first 20 min of the reaction. Furthermore, the biodegradability of the wastewater improved greatly after CWAO, the ratio of BOD5/COD increased less than 0.1-0.75 when treated at 220 °C (BOD: biochemical oxygen demand).

  11. Postprandial plasma oxyphytosterol concentrations after consumption of plant sterol or stanol enriched mixed meals in healthy subjects.

    PubMed

    Baumgartner, Sabine; Mensink, Ronald P; Konings, Maurice; Schött, Hans-F; Friedrichs, Silvia; Husche, Constanze; Lütjohann, Dieter; Plat, Jogchum

    2015-07-01

    Epidemiological studies have reported inconsistent results on the relationship between increased plant sterol concentrations with cardiovascular risk, which might be related to the formation of oxyphytosterols (plant sterol oxidation products) from plant sterols. However, determinants of oxyphytosterol formation and metabolism are largely unknown. It is known, however, that serum plant sterol concentrations increase after daily consumption of plant sterol enriched products, while concentrations decrease after plant stanol consumption. Still, we have earlier reported that fasting oxyphytosterol concentrations did not increase after consuming a plant sterol- or a plant stanol enriched margarine (3.0g/d of plant sterols or stanols) for 4weeks. Since humans are in a non-fasting state for most part of the day, we have now investigated effects on oxyphytosterol concentrations during the postprandial state. For this, subjects consumed a shake (50g of fat, 12g of protein, 67g of carbohydrates), containing no, or 3.0g of plant sterols or plant stanols. Blood samples were taken up to 8h and after 4h subjects received a second shake (without plant sterols or plant stanols). Serum oxyphytosterol concentrations were determined in BHT-enriched EDTA plasma via GC-MS/MS. 7β-OH-campesterol and 7β-OH-sitosterol concentrations were significantly higher after consumption of a mixed meal enriched with plant sterol esters compared to the control and plant stanol ester meal. These increases were seen only after consumption of the second shake, illustrative for a second meal effect. Non-oxidized campesterol and sitosterol concentrations also increased after plant sterol consumption, in parallel with 7β-OH concentrations and again only after the second meal. Apparently, plant sterols and oxyphytosterols follow the same second meal effect as described for dietary cholesterol. However, the question remains whether the increase in oxyphytosterols in the postprandial phase is due to

  12. Postprandial plasma oxyphytosterol concentrations after consumption of plant sterol or stanol enriched mixed meals in healthy subjects.

    PubMed

    Baumgartner, Sabine; Mensink, Ronald P; Konings, Maurice; Schött, Hans-F; Friedrichs, Silvia; Husche, Constanze; Lütjohann, Dieter; Plat, Jogchum

    2015-07-01

    Epidemiological studies have reported inconsistent results on the relationship between increased plant sterol concentrations with cardiovascular risk, which might be related to the formation of oxyphytosterols (plant sterol oxidation products) from plant sterols. However, determinants of oxyphytosterol formation and metabolism are largely unknown. It is known, however, that serum plant sterol concentrations increase after daily consumption of plant sterol enriched products, while concentrations decrease after plant stanol consumption. Still, we have earlier reported that fasting oxyphytosterol concentrations did not increase after consuming a plant sterol- or a plant stanol enriched margarine (3.0g/d of plant sterols or stanols) for 4weeks. Since humans are in a non-fasting state for most part of the day, we have now investigated effects on oxyphytosterol concentrations during the postprandial state. For this, subjects consumed a shake (50g of fat, 12g of protein, 67g of carbohydrates), containing no, or 3.0g of plant sterols or plant stanols. Blood samples were taken up to 8h and after 4h subjects received a second shake (without plant sterols or plant stanols). Serum oxyphytosterol concentrations were determined in BHT-enriched EDTA plasma via GC-MS/MS. 7β-OH-campesterol and 7β-OH-sitosterol concentrations were significantly higher after consumption of a mixed meal enriched with plant sterol esters compared to the control and plant stanol ester meal. These increases were seen only after consumption of the second shake, illustrative for a second meal effect. Non-oxidized campesterol and sitosterol concentrations also increased after plant sterol consumption, in parallel with 7β-OH concentrations and again only after the second meal. Apparently, plant sterols and oxyphytosterols follow the same second meal effect as described for dietary cholesterol. However, the question remains whether the increase in oxyphytosterols in the postprandial phase is due to

  13. Effects of elevated CO2 on grain yield and quality of wheat: results from a 3-year free-air CO2 enrichment experiment.

    PubMed

    Högy, P; Wieser, H; Köhler, P; Schwadorf, K; Breuer, J; Franzaring, J; Muntifering, R; Fangmeier, A

    2009-11-01

    Spring wheat (Triticum aestivum L. cv. TRISO) was grown for three consecutive seasons in a free-air carbon dioxide (CO(2)) enrichment (FACE) field experiment in order to examine the effects on crop yield and grain quality. CO(2) enrichment promoted aboveground biomass (+11.8%) and grain yield (+10.4%). However, adverse effects were predominantly observed on wholegrain quality characteristics. Although the thousand-grain weight remained unchanged, size distribution was significantly shifted towards smaller grains, which may directly relate to lower market value. Total grain protein concentration decreased significantly by 7.4% under elevated CO(2), and protein and amino acid composition were altered. Corresponding to the decline in grain protein concentration, CO(2) enrichment resulted in an overall decrease in amino acid concentrations, with greater reductions in non-essential than essential amino acids. Minerals such as potassium, molybdenum and lead increased, while manganese, iron, cadmium and silicon decreased, suggesting that adjustments of agricultural practices may be required to retain current grain quality standards. The concentration of fructose and fructan, as well as amounts per area of total and individual non-structural carbohydrates, except for starch, significantly increased in the grain. The same holds true for the amount of lipids. With regard to mixing and rheological properties of the flour, a significant increase in gluten resistance under elevated CO(2) was observed. CO(2) enrichment obviously affected grain quality characteristics that are important for consumer nutrition and health, and for industrial processing and marketing, which have to date received little attention.

  14. IMPACT OF AN OZONE GENERATOR AIR CLEANER ON STYRENE CONCENTRATIONS IN AN INDOOR AIR QUALITY RESEARCH CHAMBER

    EPA Science Inventory

    The paper gives results of an investigation of the impact of an ozone generator air cleaner on vapor-phase styrene concentrations in a full-scale indoor air quality test chamber. The time history of the concentrations of styrene and ozone is well predicted by a simulation model u...

  15. Rice grain yield and quality responses to free-air CO2 enrichment combined with soil and water warming.

    PubMed

    Usui, Yasuhiro; Sakai, Hidemitsu; Tokida, Takeshi; Nakamura, Hirofumi; Nakagawa, Hiroshi; Hasegawa, Toshihiro

    2016-03-01

    Rising air temperatures are projected to reduce rice yield and quality, whereas increasing atmospheric CO2 concentrations ([CO2 ]) can increase grain yield. For irrigated rice, ponded water is an important temperature environment, but few open-field evaluations are available on the combined effects of temperature and [CO2 ], which limits our ability to predict future rice production. We conducted free-air CO2 enrichment and soil and water warming experiments, for three growing seasons to determine the yield and quality response to elevated [CO2 ] (+200 μmol mol(-1) , E-[CO2 ]) and soil and water temperatures (+2 °C, E-T). E-[CO2 ] significantly increased biomass and grain yield by approximately 14% averaged over 3 years, mainly because of increased panicle and spikelet density. E-T significantly increased biomass but had no significant effect on the grain yield. E-T decreased days from transplanting to heading by approximately 1%, but days to the maximum tiller number (MTN) stage were reduced by approximately 8%, which limited the panicle density and therefore sink capacity. On the other hand, E-[CO2 ] increased days to the MTN stage by approximately 4%, leading to a greater number of tillers. Grain appearance quality was decreased by both treatments, but E-[CO2 ] showed a much larger effect than did E-T. The significant decrease in undamaged grains (UDG) by E-[CO2 ] was mainly the result of an increased percentage of white-base grains (WBSG), which were negatively correlated with grain protein content. A significant decrease in grain protein content by E-[CO2 ] accounted in part for the increased WBSG. The dependence of WBSG on grain protein content, however, was different among years; the slope and intercept of the relationship were positively correlated with a heat dose above 26 °C. Year-to-year variation in the response of grain appearance quality demonstrated that E-[CO2 ] and rising air temperatures synergistically reduce grain appearance quality of

  16. Clues that decaying leaves enrich Arctic air with ice nucleating particles

    NASA Astrophysics Data System (ADS)

    Conen, Franz; Stopelli, Emiliano; Zimmermann, Lukas

    2016-03-01

    Decaying leaves from Arctic regions have previously been reported to produce large numbers of ice nucleating particles (IN). Their atmospheric relevance is unclear. Our initial observations at a coastal mountain observatory in northern Norway reveal a tripling in concentrations of IN active at -15 °C (IN-15) in oceanic air after about one day of passage over land (from 1.7 and 4.9 IN-15 m-3, to 9.6 and 12.2 IN-15 m-3). Analysis of leaf litter collected near the observatory supports the earlier report of numerous IN associated with leaf litter on the ground (2 ṡ 102 IN-15 μg-1 litter particles < 5 μm). Together, both findings suggest that decaying leaves are a strong emission source of IN to the Arctic boundary layer.

  17. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air... exposures to airborne radioactive material. (b) The estimation of internal dose shall be based on...

  18. FACE: Free-Air CO[sub 2] Enrichment for plant research in the field

    SciTech Connect

    Hendrey, G.R.

    1992-08-01

    Research programs concerning the effects of Carbon Dioxide(CO)[sub 2] on cotton plants are described. Biological responses studied include foliage response to CO[sub 2] fluctuations; yield of cotton exposed to CO[sub 2] enrichment; responses of photosynthesis and stomatal conductance to elevated CO[sub 2] in field-grown cotton; cotton leaf and boll temperatures; root response to CO[sub 2] enrichment; and evaluations of cotton response to CO[sub 2] enrichment with canopy reflectance observations.

  19. FACE: Free-Air CO{sub 2} Enrichment for plant research in the field

    SciTech Connect

    Hendrey, G.R.

    1992-08-01

    Research programs concerning the effects of Carbon Dioxide(CO){sub 2} on cotton plants are described. Biological responses studied include foliage response to CO{sub 2} fluctuations; yield of cotton exposed to CO{sub 2} enrichment; responses of photosynthesis and stomatal conductance to elevated CO{sub 2} in field-grown cotton; cotton leaf and boll temperatures; root response to CO{sub 2} enrichment; and evaluations of cotton response to CO{sub 2} enrichment with canopy reflectance observations.

  20. Experimental evaluation of oxygen-enriched air and emulsified fuels in a six-cylinder diesel engine

    NASA Astrophysics Data System (ADS)

    Sekar, R. R.; Marr, W. W.; Cole, R. L.; Marciniak, T. J.; Longman, D. E.

    1993-01-01

    The objectives of this investigation are to (1) determine the technical feasibility of using oxygen-enriched air to increase the efficiency of and reduce emissions from diesel engines, (2) examine the effects of water-emulsified fuel on the formation of nitrogen oxides in oxygen-enriched combustion, and (3) investigate the use of lower-grade fuels in high-speed diesel engines by emulsifying the fuel with water. These tests, completed on a Caterpillar model 3406B, six-cylinder engine are a scale-up from previous, single-cylinder-engine tests. The engine was tested with (1) intake-air oxygen levels up to 30%, (2) water content up to 20% of the fuel, (3) three fuel-injection timings, and (4) three fuel-flow rates (power levels). The Taguchi technique for experimental design was used to minimize the number of experimental points in the test matrix. Four separate test matrices were run to cover two different fuel-flow-rate strategies and two different fuels (No. 2 diesel and No. 6 diesel). A liquid-oxygen tank located outside the test cell supplied the oxygen for the tests. The only modification of the engine was installation of a pressure transducer in one cylinder. All tests were run at 1800 rpm, which corresponds to the synchronous speed of a 60-Hz generator. Test results show that oxygen enrichment results in power increases of 50% or more while significantly decreasing the levels of smoke and particulates emitted. The increase in power was accompanied by a small increase in thermal efficiency. Maximum engine power was limited by the test-cell dynamometer capacity and the capacity of the fuel-injection pump. Oxygen enrichment increases nitrogen-oxide emissions significantly. No adverse effects of oxygen enrichment on the turbocharger were observed. The engine operated successfully with No. 6 fuel, but it operated at a lower thermal efficiency and emitted more smoke and particulates than with No. 2 fuel.

  1. The photosynthetic acclimation of Lolium perenne growing in a free-air CO{sub 2} enrichment (FACE) system

    SciTech Connect

    Bryant, J.B. |

    1994-11-01

    Stands of Ryegrass (Lolium perenne L. cv. Bastion) were grown in the field at ambient or elevated (600{mu}mol/mol) CO{sub 2} concentration, high (560Kg/ha) or low (140Kg/ha) nitrogen addition and with a frequent (every 4 weeks) or infrequent (every 8 weeks) cutting regime. Plants were in the second year of a 3 year experiment. Exposure to elevated CO{sub 2} was carried out with a Free-Air CO{sub 2} Enrichment (FACE) system which provides the most {open_quote}realistic{close_quote} system of CO{sub 2} fumigation currently available. Elevated CO{sub 2} increased diurnal CO{sub 2} assimilation by between 34 and 88% whilst reducing rates of stomatal conductance by between 1 and 42%. However, analysis of the A vs. Ci response showed considerable acclimation of the photosynthetic apparatus in response to elevated CO{sub 2} - Vc{sub max} as an in vivo measure of RubisCO activity, decreased by between 29 and 35% in high CO{sub 2}, whilst J{sub max}, as a measure of the RubP regeneration capacity, showed no significant change. Two out of three additional perennial grassland species studied showed similar acclamatory behavior to Ryegrass. Diurnal assimilation rate, J{sub max} and, in most cases, Vc{sub max}, increased significantly directly after cutting of Ryegrass stands, but nitrogen treatment had little effect on any of these parameters. Neither stomatal density, stomatal index nor stomatal pore length of Ryegrass were significantly altered by growth in elevated CO{sub 2}. The results are discussed in terms of the limitation imposed on maximizing photosynthetic and growth responses of Ryegrass at elevated CO{sub 2}, by the ability of perennial species to increase long-term sink capacity under these conditions.

  2. Free Air C02 Enrichment (FACE) Research Data from the Oak Ridge FACE Site and Experiment on CO2 Enrichment of Sweetgum

    DOE Data Explorer

    DOE has conducted trace gas enrichment experiments since the mid 1990s. The FACE Data Management System is a central repository and archive for Free-Air Carbon Dioxide Enrichment (FACE) data, as well as for the related open-top chamber (OTC) experiments. FACE Data Management System is located at DOE’s Carbon Dioxide Information Analysis Center (CDIAC). While the data from the various FACE sites, each one a unique user facility, are centralized at CDIAC, each of the FACE sites presents its own view of its activities and information. For that reason, DOE Data Explorer users are advised to see both the central repository at http://public.ornl.gov/face/index.shtml and the individual home pages of each site. The goal of the Oak Ridge FACE Experiment on C02 Enrichment of Sweetgum is to understand how the eastern deciduous forest will be affected by C02 enrichment of the atmosphere, and what are the feedbacks from the forest to the atmosphere. This goal is being approached by measuring the integrated response of an intact forest ecosystem, with a focus on stand-level mechanisms. The facility, comprising five 25-m plots was constructed in a deciduous forest on the Oak Ridge National Environmental Research Park. The study site is a sweetgum (Liquidambar styraciflua) monoculture planted in 1988. This closed-canopy, 18-m tall stand offers the opportunity for rigorous tests of hypotheses that address the essential features of a forest stand and how they could influence the responses to CO2. The facility was established with support from the ORNL Director's R&D Fund and the Biological and Environmental Research program of the U. S. Department of Energy Office of Science. Additional support was provided by the Terrestrial Ecology and Global Change (TECO) program through the National Science Foundation. This project was part of the CO2 research network fostered by the Global Change and Terrestrial Ecosystems core project of the International Geosphere-Biosphere Programme

  3. Growth and enrichment of pentachlorophenol-degrading microorganisms in the nutristat, a substrate concentration-controlled continuous culture.

    PubMed Central

    Rutgers, M; Bogte, J J; Breure, A M; van Andel, J G

    1993-01-01

    The nutristat, a substrate concentration-controlled continuous culture, was used to grow pentachlorophenol (PCP)-degrading microorganisms. The PCP concentration control system consisted of on-line measurement of the PCP concentration in the culture vessel with a tangential filter and a flowthrough spectrophotometer. With PCP concentrations between 45 and 77 microM, a stable situation was established in the nutristat, with an average dilution rate of 0.035 +/- 0.003 h-1. Compared with those of fed-batch cultures and chemostat cultures, the growth rates of microorganisms in the PCP nutristat were significantly higher, leading to considerable time savings in the enrichment procedure. In addition, PCP accumulation to severe inhibitory levels in the culture is prevented because the set point determines the (maximum) PCP concentration in the culture. The use of the nutristat as a tool for the growth of bacteria that degrade toxic compounds is discussed. PMID:8250560

  4. Atmospheric light air ion concentrations and related meteorologic factors in Rezekne city, Latvia.

    PubMed

    Skromulis, Andris; Noviks, Gotfrids

    2012-04-01

    The well-minded impact of light negative air ions on human organism is still under discussion. The measurements of air ions are not widespread in Latvia yet. The paper presents new results of air pollution evaluation in Rezekne city. Measurements of positive and negative air ion concentrations in Rezekne city were taken during the spring, summer and autumn 2009 and during the winter 2010. Measurements were taken by portative air ions counter "Sapfir-3M" in eight different points of Rezekne city thrice a day. The concentrations of positive and negative air ions with mobility factor k > or = 0.4 cm2 V(-1) s(-1) were measured. Temperature, relative humidity, wind velocity, direction, etc., were also taken into account. The approximate interconnection between ionization and chemical and mechanical air pollution in relation with meteorological conditions was analyzed. The highest level of air ion concentration was observed in mornings, whereas in afternoons this concentration level decreased due to the growth of anthropogenic air pollution in the city, as light air ions, because of their charge, promoted the coagulation and the settlement of pollution particles. This regularity is typical for summer, whereas in spring, autumn and winter it is not characteristic. The unipolarity factor was usually less than 1 in mornings, but usually larger than 1 in afternoons especially in the most polluted city areas where minor concentration of air ions was detected. The ionization level is an original indicator of energetic saturation and aerosol pollution of atmospheric air.

  5. Assessment of air quality in the coastal area of South Korea using principal component analysis combined with cluster analysis and enrichment factor

    NASA Astrophysics Data System (ADS)

    Yoo, H.; Kwack, W.; Ha, H.; Choe, C.; Kim, Y.; Zoh, K.; Yi, S.

    2009-12-01

    The interpretation of ambiet air pollution in relation with meteorological parameters is a topic of great interest to maintain and manage ambient air quality in the coastal region of South Korea. The objectives of this study were: (i) to locate emission sources qualitatitively and quantitatively, (ii) to identify air quality by day with similar air pollution behaviors; and (iii) to evaluate the effect of sea salt on the aerosols. Two statistical techniques, principal components analysis(PCA) and cluster analysis(CA) were applied to the concentrations of five pollutants(PM10, SO2, NO2, CO and O3). The enrichment factor(EF) representing the ratio of Cl/Na in aerosol to Cl/Na in sea water was calculated with 2 soluble ions(Na+ and Cl-) in PM10 analyzed by ion chromatograph in coastal urban area of Incheon city, South Korea from January to December 2008. PCA results show three emission sources; (i) high PM10, NO2 and CO with low temperature, radiation and wind speed(35.9%), (ii) high O3 with high radiation and wind speed, and low humidity(18.2%), (iii) high NO2 and O3 with high temperature and radiation, and low wind speed(11.2%), respectively. CA results show three groups; (i) Friday (high PM10 and NO2, low O3), (ii) Sunday (low PM10 and NO2, high O3), (iii) Monday/Tuesday/Wednesday/Thursday/Saturday (medium PM10, NO2 and O3). EF was 1.02 implying contribution of sea salt on the aerosol level with various anthropogenic sources. In conclusion, PCA and CA are suitable for idenfying and estimating the sources of air pollution. EF allows for investigating the effect of sea salt on the PM10 in the region where sea-land breezes. It was conclueded that the sea wind had an important contribution towards the variation of air pollutants. Key words : air pollutants, principal component analysis, cluster analysis, enrichment factor Fig. 1. Dendrogram using average linkage of cluster analysis for PM10 at coastal urban area of Incheon, South Korea. Table 1 Main results of PCA

  6. Effect of plant sterol-enriched diets on plasma and egg yolk cholesterol concentrations and cholesterol metabolism in laying hens.

    PubMed

    Liu, X; Zhao, H L; Thiessen, S; House, J D; Jones, P J H

    2010-02-01

    Egg exists as a major dietary source of cholesterol in Western diets. In North America, laying hen diets are usually devoid of cholesterol when diets are formulated to exclude animal-based products. Hence, laying hens meet their physiological cholesterol requirement through de novo synthesis. Plant sterols exert a cholesterol-lowering effect in humans by interfering with intestinal sterol absorption. However, it is unknown whether plant sterol supplementation could be effective in reducing intestinal reabsorption of biliary cholesterol in laying hens, thus modulating whole body cholesterol in favor of lower plasma and yolk cholesterol content. The current study was designed to investigate the effect of diets enriched with 0, 0.5, 1, and 2% plant sterols on cholesterol absorption, synthesis, as well as plasma, liver, and egg yolk cholesterol concentrations in laying hens. After 8 wk of plant sterol intervention (first 2 wk were acclimatization), feed intake, BW, egg weight, egg yolk weight, egg production, Haugh units, liver mass, plasma, and hepatic cholesterol concentrations did not differ as a function of plant sterol supplementation. Egg cholesterol concentrations (mg/g) fluctuated during the 6-wk experimental period. At wk 6, a minor reduction in egg yolk cholesterol concentration (mg per g of yolk, P<0.05, vs. control) was observed in hens fed 1 and 2% cholesterol-enriched diets, respectively. However, such result failed to affect total egg cholesterol content. No statistical difference was observed across treatments over 6 wk. Neither cholesterol absorption rates nor synthesis differed as a function of treatment. Results suggested that overall cholesterol content in egg yolk was not affected by feeding hens plant sterol-enriched diets over 6 wk. PMID:20075279

  7. Modeling Airborne Beryllium Concentrations From Open Air Dynamic Testing

    NASA Astrophysics Data System (ADS)

    Becker, N. M.

    2003-12-01

    A heightened awareness of airborne beryllium contamination from industrial activities was reestablished during the late 1980's and early 1990's when it became recognized that Chronic Beryllium Disease (CBD) had not been eradicated, and that the Occupational Health and Safety Administration standards for occupational air exposure to beryllium may not be sufficiently protective. This was in response to the observed CBD increase in multiple industrial settings where beryllium was manufactured and/or machined, thus producing beryllium particulates which are then available for redistribution by airborne transport. Sampling and modeling design activities were expanded at Los Alamos National Laboratory in New Mexico to evaluate potential airborne beryllium exposure to workers who might be exposed during dynamic testing activities associated with nuclear weapons Stockpile Stewardship. Herein is presented the results of multiple types of collected air measurements that were designed to characterize the production and dispersion of beryllium used in components whose performance is evaluated during high explosive detonation at open air firing sites. Data from fallout, high volume air, medium volume air, adhesive film, particle size impactor, and fine-particulate counting techniques will be presented, integrated, and applied in dispersion modeling to assess potential onsite and offsite personal exposures resulting from dynamic testing activities involving beryllium.

  8. Global Ammonia Concentrations Seen by the 13-years AIRS Measurements

    NASA Astrophysics Data System (ADS)

    Warner, Juying; Wei, Zigang; Larrabee Strow, L.; Dickerson, Russell; Nowak, John; Wang, Yuxuan

    2016-04-01

    Ammonia is an integral part of the nitrogen cycle and is projected to be the largest single contributor to each of acidification, eutrophication and secondary particulate matter in Europe by 2020 (Sutton et al., 2008). The impacts of NH3 also include: aerosol production affecting global radiative forcing, increases in emissions of the greenhouse gases nitrous oxide (N2O) and methane (CH4), and modification of the transport and deposition patterns of SO2 and NOx. Therefore, monitoring NH3 global distribution of sources is vitally important to human health with respect to both air and water quality and climate change. We have developed new daily and global ammonia (NH3) products from AIRS hyperspectral measurements. These products add value to AIRS's existing products that have made significant contributions to weather forecasts, climate studies, and air quality monitoring. With longer than 13 years of data records, these measurements have been used not only for daily monitoring purposes but also for inter-annual variability and short-term trend studies. We will discuss the global NH3 emission sources from biogenic and anthropogenic activities over many emission regions captured by AIRS. We will focus their variability in the last 13 years.

  9. LARGE-SCALE PREDICTIONS OF MOBILE SOURCE CONTRIBUTIONS TO CONCENTRATIONS OF TOXIC AIR POLLUTANTS

    EPA Science Inventory

    This presentation shows concentrations and deposition of toxic air pollutants predicted by a 3-D air quality model, the Community Multi Scale Air Quality (CMAQ) modeling system. Contributions from both on-road and non-road mobile sources are analyzed.

  10. Effect of an ozone-generating air-purifying device on reducing concentrations of formaldehyde in air

    SciTech Connect

    Esswein, E.J.; Boeniger, M.F.

    1994-02-01

    Formaldehyde, an air contaminant found in many indoor air investigations, poses distinct occupational exposure hazards in certain job categories (e.g., mortuary science) but is also of concern when found or suspected in office buildings and homes. A variety of air-purifying devices (APDs) are currently available or marketed for application to reduce or remove concentrations of a variety of indoor air pollutants through the use of ozone as a chemical oxidant. An investigation was conducted to determine if concentrations of formaldehyde similar to those found in industrial hygiene evaluations of funeral homes could be reduced with the use of an ozone-generating APD. An ozone-generating APD was placed in an exposure chamber and formaldehyde-containing embalming solution was allowed to evaporate naturally, creating peak and mean chamber concentrations of 2.5 and 1.3 ppm, respectively. Continuous-reading instruments were used to sample for formaldehyde and ozone. Active sampling methods were also used to sample simultaneously for formaldehyde and a possible reactant product, formic acid. Triplicate measurements were made in each of three evaluations: formaldehyde alone, ozone alone, and formaldehyde and ozone combined. Concentrations of formaldehyde were virtually identical with and without 0.5 ppm ozone. No reduction in formaldehyde concentration was found during a 90-minute evaluation using ozone at this concentration with peak and average concentrations of approximately 2.5 and 1.3 ppm formaldehyde, respectively. The results of this investigation suggest that the use of ozone is ineffective in reducing concentrations of formaldehyde. Because ozone has demonstrated health hazards, and is a regulated air contaminant in both the occupational and ambient environment, the use of ozone as an air purification agent in indoor air does not seem warranted. 25 refs., 5 figs., 4 tabs.

  11. A new test method for the assessment of the arc tracking properties of wire insulation in air, oxygen enriched atmospheres and vacuum

    NASA Technical Reports Server (NTRS)

    Koenig, Dieter

    1994-01-01

    Development of a new test method suitable for the assessment of the resistance of aerospace cables to arc tracking for different specific environmental and network conditions of spacecraft is given in view-graph format. The equipment can be easily adapted for tests at different realistic electrical network conditions incorporating circuit protection and the test system works equally well whatever the test atmosphere. Test results confirm that pure Kapton insulated wire has bad arcing characteristics and ETFE insulated wire is considerably better in air. For certain wires, arc tracking effects are increased at higher oxygen concentrations and significantly increased under vacuum. All tests on different cable insulation materials and in different environments, including enriched oxygen atmospheres, resulted in a more or less rapid extinguishing of all high temperature effects at the beginning of the post-test phase. In no case was a self-maintained fire initiated by the arc.

  12. Does anthropogenic nitrogen enrichment increase organic nitrogen concentrations in runoff from forested and human-dominated watersheds?

    USGS Publications Warehouse

    Pellerin, B.A.; Kaushal, S.S.; McDowell, W.H.

    2006-01-01

    Although the effects of anthropogenic nitrogen (N) inputs on the dynamics of inorganic N in watersheds have been studied extensively, "the influence of N enrichment on organic N loss" is not as well understood. We compiled and synthesized data on surface water N concentrations from 348 forested and human-dominated watersheds with a range of N loads (from less than 100 to 7,100 kg N km-2 y-1) to evaluate the effects of N loading via atmospheric deposition, fertilization, and wastewater on dissolved organic N (DON) concentrations. Our results indicate that, on average, DON accounts for half of the total dissolved N (TDN) concentrations from forested watersheds, but it accounts for a smaller fraction of TDN in runoff from urban and agricultural watersheds with higher N loading. A significant but weak correlation (r 2 = 0.06) suggests that N loading has little influence on DON concentrations in forested watersheds. This result contrasts with observations from some plot-scale N fertilization studies and suggests that variability in watershed characteristics and climate among forested watersheds may be a more important control on DON losses than N loading from atmospheric sources. Mean DON concentrations were positively correlated, however, with N load across the entire land-use gradient (r 2 = 0.37, P < 0.01), with the highest concentrations found in agricultural and urban watersheds. We hypothesize that both direct contributions of DON from wastewater and agricultural amendments and indirect transformations of inorganic N to organic N represent important sources of DON to surface waters in human-dominated watersheds. We conclude that DON is an important component of N loss in surface waters draining forested and human-dominated watersheds and suggest several research priorities that may be useful in elucidating the role of N enrichment in watershed DON dynamics. ?? 2006 Springer Science+Business Media, Inc.

  13. Anaerobic Biotransformation of High Concentrations of Chloroform by an Enrichment Culture and Two Bacterial Isolates ▿ †

    PubMed Central

    Shan, Huifeng; Kurtz, Harry D.; Mykytczuk, Nadia; Trevors, Jack T.; Freedman, David L.

    2010-01-01

    A fermentative enrichment culture (designated DHM-1) was developed that is capable of cometabolically biotransforming high concentrations of chloroform (CF) to nontoxic end products. Two Pantoea spp. were isolated from DHM-1 that also possess this dechlorination capability. Following acclimation to increasing levels of CF, corn syrup-grown DHM-1 was able to transform over 500 mg/liter CF in the presence of vitamin B12 (approximately 3% of CF on a molar basis) at a rate as high as 22 mg/liter/day in a mineral salts medium. CO, CO2, and organic acids were the predominant biodegradation products, suggesting that hydrolytic reactions predominate during CF transformation. DHM-1 was capable of growing on corn syrup in the presence of high concentrations of CF (as may be present near contaminant source zones in groundwater), which makes it a promising culture for bioaugmentation. Strains DHM-1B and DHM-1T transform CF at rates similar to that of the DHM-1 enrichment culture. The ability of these strains to grow in the presence of high concentrations of CF appears to be related to alteration of membrane fluidity or homeoviscous and homeophasic adaptation. PMID:20693443

  14. Time variations of 222Rn concentration and air exchange rates in a Hungarian cave.

    PubMed

    Nagy, Hedvig Éva; Szabó, Zsuzsanna; Jordán, Gyozo; Szabó, Csaba; Horváth, Akos; Kiss, Attila

    2012-09-01

    A long-term radon concentration monitoring was carried out in the Pál-völgy cave, Budapest, Hungary, for 1.5 years. Our major goal was to determine the time dependence of the radon concentration in the cave to characterise the air exchange and define the most important environmental parameters that influence the radon concentration inside the cave. The radon concentration in the cave air was measured continuously by an AlphaGuard radon monitor, and meteorological parameters outside the cave were collected simultaneously. The air's radon concentration in the cave varied between 104 and 7776 Bq m(-3), the annual average value was 1884±85 Bq m(-3). The summer to winter radon concentration ratio was as high as 21.8. The outside air temperature showed the strongest correlation with the radon concentration in the cave, the correlation coefficient (R) was 0.76. PMID:22462600

  15. Limitations to soybean photosynthesis at elevated carbon dioxide in free-air enrichment and open top chamber systems.

    PubMed

    Bunce, James A

    2014-09-01

    It has been suggested that the stimulation of soybean photosynthesis by elevated CO2 was less in free-air carbon dioxide enrichment (FACE) systems than in open top chambers (OTC), which might explain smaller yield increases at elevated CO2 in FACE systems. However, this has not been tested using the same cultivars grown in the same location. I tested whether soybean photosynthesis at high light and elevated CO2 (ambient+180 μmol mol(-1)) was limited by electron transport (J) in FACE systems but by ribulose-bisphosphate carboxylation capacity (VCmax) in OTC. FACE systems with daytime and continuous CO2 enrichment were also compared. The results indicated that in both cultivars examined, midday photosynthesis at high light was always limited by VCmax, both in the FACE and in the OTC systems. Daytime only CO2 enrichment did not affect photosynthetic parameters or limitations, but did result in significantly smaller yields in both cultivars than continuous elevation. Photosynthesis measured at low photosynthetic photon flux density (PPFD) was not higher at elevated than at ambient CO2, because of an acclimation to elevated CO2 which was only evident at low measurement PPFDs.

  16. The photosynthetic and stomatal response of Medicago sativa cv. saranac to free-air CO{sub 2} enrichment (F.A.C.E.) and nitrogen

    SciTech Connect

    Bridson, N.P.

    1996-08-01

    Plots of Medicago sativa cv. saranac were grown in the field at ambient (355 {mu}mol CO{sub 2} mol{sup -1} air) or elevated (600{mu}mol CO{sub 2} mol{sup -1} air) CO{sub 2} concentrations. High (200kg yr{sup -1}) or low (20kg yr{sup -1}) nitrogen levels were applied to two isogeneic lines, one able and one unable to use nitrogen fixing bacteria. Plants were in the second year of field growth. Exposure to elevated CO{sub 2} was via a Free-Air CO{sub 2} Enrichment System (FACE). Elevated CO{sub 2} increased diurnal assimilation by between 12% and 92%. Analysis of A/C{sub i} responses showed that effective nitrogen fertilisation was more important to rubisCO and RuBP activity than elevated CO{sub 2}. No acclimation was consistently observed. Leaves lower down the canopy were found to have lower Vc{sub max} and J{sub max} values, though age may be the cause of the latter effect. FACE conditions have only a small effect on these responses. There was some evidence found for the down-regulation of photosynthesis in the late afternoon. The FACE conditions had no affect on stomatal density but did increase epidermal cell density.

  17. The concentrations of culturable microorganisms in relation to particulate matter in urban air

    NASA Astrophysics Data System (ADS)

    Haas, D.; Galler, H.; Luxner, J.; Zarfel, G.; Buzina, W.; Friedl, H.; Marth, E.; Habib, J.; Reinthaler, F. F.

    2013-02-01

    The ambient air consists not only of gases but also of bioaerosols and particulate matter. The concentrations of particulate matter in relation to the culturable microorganisms in the urban ambient air and their dependence on air temperature and relative humidity were investigated. The seasonal distribution of particles sizes, the concentrations of aerobic mesophilic bacteria and xerophilic fungi in the air were evaluated. Moreover, the identification of the fungal genera Cladosporium, Aspergillus and Penicillium were conducted. Within one year at 177 days particle and microorganism concentrations in the ambient air were recorded in the city centre of Graz/Austria. The results show that the concentrations of fine particles and coarse particles were the highest in winter and decreased continuously to a minimum in the summer months depending on temperature and air humidity. The concentrations of xerophilic fungi showed no correlation to the different particle concentrations. The spore concentrations of Cladosporium spp. showed the same results of xerophilic fungi whereas the genera Penicillium and Aspergillus increased with the increase of fine particles. The concentrations of mesophilic bacteria were positively correlated with all particle counts. The maximum mesophilic bacteria concentrations were found in the winter months. Further studies are required to evaluate the concentrations of specific microorganisms in the natural environment in relation to the particulate matter.

  18. Triclosan enriches for Dehalococcoides-like Chloroflexi in anaerobic soil at environmentally relevant concentrations.

    PubMed

    McNamara, Patrick J; Krzmarzick, Mark J

    2013-07-01

    Triclosan is an antimicrobial agent that is discharged to soils with land-applied wastewater biosolids, is persistent under anaerobic conditions, and yet its impact on anaerobic microbial communities in soils is largely unknown. We hypothesized that triclosan enriches for Dehalococcoides-like Chloroflexi because these bacteria respire organochlorides and are likely less sensitive, relative to other bacteria, to the antimicrobial effects of triclosan. Triplicate anaerobic soil microcosms were seeded with agricultural soil, which was not previously exposed to triclosan, and were amended with 1 mg kg(-1) of triclosan. Triplicate control microcosms did not receive triclosan, and the experiment was run for 618 days. The overall bacterial community (assessed by automated ribosomal intergenic spacer analysis and denaturing gradient gel electrophoresis) was not impacted by triclosan; however, the abundance of Dehalococcoides-like Chloroflexi 16S rRNA genes (determined by qPCR) increased 20-fold with triclosan amendment compared with a fivefold increase without triclosan. This work demonstrates that triclosan impacts anaerobic soil communities at environmentally relevant levels.

  19. AN INDOOR PESTICIDE AIR AND SURFACE CONCENTRATION MODEL

    EPA Science Inventory

    A thorough assessment of human exposure to environmental chemicals requires consideration of all processes in the sequence from source to dose. For assessment of exposure to pesticides following their use indoors, data and models are needed to estimate pesticide concentrations...

  20. Intramyocellular diacylglycerol concentrations and [U-¹³C]palmitate isotopic enrichment measured by LC/MS/MS.

    PubMed

    Blachnio-Zabielska, Agnieszka U; Zabielski, Piotr; Jensen, Michael D

    2013-06-01

    Diacylglycerols (DAG) are important lipid metabolites thought to induce muscle insulin resistance when present in excess; they can be synthesized de novo from plasma free fatty acids (FFA) or generated by hydrolysis of preexisting intracellular lipids. We present a new method to simultaneously measure intramyocellular concentrations of and the incorporation of [U-¹³C]palmitate from an intravenous infusion into individual DAG species. DAG were extracted from pulverized muscle samples using isopropanol:water:ethyl acetate (35:5:60; v:v:v). Chromatographic separation was conducted on reverse-phase column in binary gradient using 1.5 mM ammonium formate, 0.1% formic acid in water as solvent A, and 2 mM ammonium formate, 0.15% formic acid in methanol as solvent B. We used UPLC-ESI⁺-MS/MS in the multiple reaction monitoring (MRM) mode to separate the ions of interest from sample. Because DAG are a neutral lipid class, they were monitored as an ammonium adduct [M+NH4]⁺. To measure isotopic enrichment (for ¹³C16:0/16:0-DAG and ¹³C16:0/C18:1-DAG), we monitored the basic ions as [M+2+NH4]⁺ and the enriched compounds as [M+16+NH4]⁺. We were able to measure concentration and enrichment using 20 mg of skeletal muscle samples obtained from rats receiving a continuous infusion of [U-¹³C]palmitate. Applying this protocol to biological muscle samples proves that the method is sensitive, accurate, and efficient.

  1. Intramyocellular diacylglycerol concentrations and [U-13C]palmitate isotopic enrichment measured by LC/MS/MS

    PubMed Central

    Blachnio-Zabielska, Agnieszka U.; Zabielski, Piotr; Jensen, Michael D.

    2013-01-01

    Diacylglycerols (DAG) are important lipid metabolites thought to induce muscle insulin resistance when present in excess; they can be synthesized de novo from plasma free fatty acids (FFA) or generated by hydrolysis of preexisting intracellular lipids. We present a new method to simultaneously measure intramyocellular concentrations of and the incorporation of [U-13C]palmitate from an intravenous infusion into individual DAG species. DAG were extracted from pulverized muscle samples using isopropanol:water:ethyl acetate (35:5:60; v:v:v). Chromatographic separation was conducted on reverse-phase column in binary gradient using 1.5 mM ammonium formate, 0.1% formic acid in water as solvent A, and 2 mM ammonium formate, 0.15% formic acid in methanol as solvent B. We used UPLC-ESI+-MS/MS in the multiple reaction monitoring (MRM) mode to separate the ions of interest from sample. Because DAG are a neutral lipid class, they were monitored as an ammonium adduct [M+NH4]+. To measure isotopic enrichment (for 13C16:0/16:0-DAG and 13C16:0/C18:1-DAG), we monitored the basic ions as [M+2+NH4]+ and the enriched compounds as [M+16+NH4]+. We were able to measure concentration and enrichment using 20 mg of skeletal muscle samples obtained from rats receiving a continuous infusion of [U-13C]palmitate. Applying this protocol to biological muscle samples proves that the method is sensitive, accurate, and efficient. PMID:23511896

  2. Concentrations of Cu, growth, and chlorophyll content of field-cultivated wheat growing in naturally enriched Cu soil

    SciTech Connect

    Cook, C.M.; Vardaka, E.; Lanaras, T.

    1997-02-01

    The Serbo-Macedonian massif of northern Greece is notable for the occurrence of numerous small areas of sulphide mineralisation. Varying degrees of porphyry copper mineralisation, associated with post-Miocene volcanic rocks of rhyolitic composition, can be encountered in agricultural fields which are used mainly for wheat production. Although Cu is a trace element essential to plant nutrition, in excess, it is phytotoxic causing stunted growth, chlorosis and root malformation. Previous studies on wheat growing in these naturally enriched Cu soils have shown that plants have reduced growth, chlorosis and chloroplast ultrastructural changes and a reduced efficiency of the photochemistry of photosystem II (PSII). The objective of this study was to examine the relationship between the Cu concentration of the soil and the plant tissue Cu concentration, growth and chlorophyll content of field-cultivated wheat growing in soils with varying degrees of porphyry copper mineralisation. 15 refs., 2 figs., 1 tab.

  3. High cell density cultivation of Pseudomonas putida KT2440 using glucose without the need for oxygen enriched air supply.

    PubMed

    Davis, Reeta; Duane, Gearoid; Kenny, Shane T; Cerrone, Federico; Guzik, Maciej W; Babu, Ramesh P; Casey, Eoin; O'Connor, Kevin E

    2015-04-01

    High Cell Density (HCD) cultivation of bacteria is essential for the majority of industrial processes to achieve high volumetric productivity (g L(-1) h(-1) ) of a bioproduct of interest. This study developed a fed batch bioprocess using glucose as sole carbon and energy source for the HCD of the well described biocatalyst Pseudomonas putida KT2440 without the supply of oxygen enriched air. Growth kinetics data from batch fermentations were used for building a bioprocess model and designing feeding strategies. An exponential followed by linearly increasing feeding strategy of glucose was found to be effective in maintaining biomass productivity while also delaying the onset of dissolved oxygen (supplied via compressed air) limitation. A final cell dry weight (CDW) of 102 g L(-1) was achieved in 33 h with a biomass productivity of 3.1 g L(-1) h(-1) which are the highest ever reported values for P. putida strains using glucose without the supply of pure oxygen or oxygen enriched air. The usefulness of the biomass as a biocatalyst was demonstrated through the production of the biodegradable polymer polyhydroxyalkanoate (PHA). When nonanoic acid (NA) was supplied to the glucose grown cells of P. putida KT2440, it accumulated 32% of CDW as PHA in 11 h (2.85 g L(-1) h(-1) ) resulting in a total of 0.56 kg of PHA in 18 L with a yield of 0.56 g PHA g NA(-1) .

  4. Pasting and rheological properties of ß-glucan-enriched hydrocolloids from oat bran concentrate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pasting and rheological properties of four oat hydrocolloids with different contents of ß-glucan (Nutrim10, C-Trim20, C-Trim30, and C-Trim50) were characterized and compared with oat bran concentrate (OBC) and ß-Glucan 95%. C-Trim30 and C-Trim50 had significantly higher water holding capacities comp...

  5. Concentrations, enrichment and predominant sources of Sb and other trace elements in size classified airborne particulate matter collected in Tokyo from 1995 to 2004.

    PubMed

    Furuta, Naoki; Iijima, Akihiro; Kambe, Akiko; Sakai, Kazuhiro; Sato, Keiichi

    2005-12-01

    APM was collected and trace elements existing in the particles were monitored since May 1995 in this study. APM sample was collected separately by size (d < 2 microm, 2-11 microm and >11 microm) on the roof of the university building (45 m above ground) in the campus of Faculty of Science and Engineering, Chuo University, Tokyo, Japan, using an Anderson low volume air sampler. The collected sample was digested by HNO3, H2O2 and HF using a microwave oven, and major elements (Na, Mg, Al, K, Ca and Fe) were measured by ICP-AES, and trace elements (Li, Be, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sb, Ba and Pb) were measured by ICP-MS. It was observed that the APM concentration was higher between the winter and the spring, compared to during the summer. The enrichment factor was calculated for each element in each set of APM (d < 2 microm, 2-11 microm and >11 microm). Seasonal trends of enrichment factors were examined, and the elements were classified into 3 groups according to the common seasonal behavior. It is likely that the elements in the same group have common origins. Toxic pollutant elements (Sb, Se, Cd, Pb and As) were found in small particles with d of <2 microm in concentrated levels. Antimony (Sb) had the highest enrichment factor, and the results suggested that Sb level in APM was extremely high. The origins of Sb were sought, and wastes from plastic incineration and brake pad wears of automobiles were suspected. Each set of APM (d < 2 microm, 2-11 microm and >11 microm) was classified by the shape, and the shape-dependent constituents of a single APM particle were quantitatively measured by SEM-EDX. High concentration of Sb was found in APM <2 microm and square particles. Particles less than 2 microm and square shaped particles were major particles produced by actual car braking experiments. From these experimental results it was concluded that the source of Sb in squared APM <2 microm is considered to be from brake pad wear. PMID:16307066

  6. Effect of air pollution and environmental tobacco smoke on serum hyaluronate concentrations in school children

    PubMed Central

    Fuji, Y; Shima, M; Ando, M; Adachi, M; Tsunetoshi, Y

    2002-01-01

    Objectives: To evaluate serum hyaluronate concentrations relative to air pollution, environmental tobacco smoke (ETS), and respiratory health in Japanese school children. Methods: Respiratory symptoms and serum IgE concentrations were examined in 1037 school children living in four communities in Japan with differing levels of air pollution. Serum hyaluronate concentrations were assayed in 230 children, consisting of all the children who had symptoms of either asthma or wheeze (65 and 50 subjects, respectively) and normal controls adjusted for sex, school grade, and school without these symptoms (115 subjects). Results: Although serum hyaluronate concentrations did not differ for either asthma or wheeze, the concentrations were significantly higher in children living in communities with higher levels of air pollution. Children with asthma or wheeze and those with serum IgE concentrations of 250 IU/ml or above showed differences in hyaluronate concentrations that related to the degree of air pollution in the communities. In children with higher serum IgE concentrations, the hyaluronate concentrations among subjects exposed to ETS were significantly higher than among those without exposure to ETS. Conclusions: The present results suggest that serum hyaluronate concentration is related to the degree of air pollution and exposure to ETS. Children with asthma or wheeze and children with higher IgE concentrations are considered to be more susceptible to environmental factors. PMID:11850556

  7. Effect of air preheat temperature and oxygen concentration on flame structure and emission

    SciTech Connect

    Bolz, S.; Gupta, A.K.

    1998-07-01

    The structure of turbulent diffusion flames with highly preheated combustion air (air preheat temperature in excess of 1,150 C) has been obtained using a specially designed regenerative combustion furnace. Propane gas was used as the fuel. Data have been obtained on the global flame features, spectral emission characteristics, spatial distribution of OH, CH and C{sub 2} species, and pollutants emission from the flames. The results have been obtained for various degrees of air preheat temperatures and O{sub 2} concentration in the air. The color of the flame was found to change from yellow to blue to bluish-green to green over the range of conditions examined. In some cases a hybrid color flame was also observed. The recorded images of the flame photographs were analyzed using color-analyzing software. The results show that thermal and chemical flame behavior strongly depends on the air preheat temperature and oxygen content in the air. The flame color was found to be bluish-green or green at very high air preheat temperatures and low-oxygen concentration. However, at high oxygen concentration the flame color was yellow. The flame volume was found to increase with increase in air-preheat temperature and decrease in oxygen concentration. The flame length showed a similar behavior. The concentrations of OH, CH and C{sub 2} increased with an increase in air preheat temperatures. These species exhibited a two-stage combustion behavior at low oxygen concentration and single stage combustion behavior at high oxygen concentration in the air. Stable flames were obtained for remarkably low equivalence ratios, which would not be possible with normal combustion air. Pollutants emission, including CO{sub 2} and NO{sub x} , was much lower with highly preheated combustion air at low O{sub 2} concentration than the normal air. The results also suggest uniform flow and flame thermal characteristics with conditioned highly preheated air. Highly preheated air combustion provides much

  8. Cotton root and rhizosphere responses to free-air CO{sub 2} enrichment

    SciTech Connect

    Rogers, H.H.; Prior, S.A.; O`Neill, E.G.

    1992-12-31

    Plant responses to above-ambient levels of CO{sub 2} have been summarized in several excellent reviews of recent origin, each with its own special intent. Very little is known of how root and rhizosphere processes are affected by additional CO{sub 2}. To help fill this gap in our knowledge base we have begun work in this area. Herein, we describe the early results of a first ever study of cotton growing in an open filed enriched with CO{sub 2}. Data suggest that elevated atmospheric CO{sub 2} stimulates cotton root proliferation. It may be inferred that other below ground processes impacted by root proliferation could also shift. Both root length density and root weight density appear to increase, especially in the upper layers of the soil profile. Enhanced growth of cotton roots resulted in a more thorough exploration of the soil volume occupied, possibly increasing water and nutrient availability. Increased rooting induced by CO{sub 2} enrichment could become very important for seedling establishment, especially for a crop under stress. For agronomic conditions where water and nutrients are essentially unlimited, denser root patterns may have less significance than under the limiting circumstances of more primitive or sustainable agricultural systems, or in natural ecosystems. A more thorough understanding of the implications of CO{sub 2}-enhanced root growth must await further experimentation. 43 refs., 2 figs., 10 tabs.

  9. Daily and seasonal variations in radon activity concentration in the soil air.

    PubMed

    Műllerová, Monika; Holý, Karol; Bulko, Martin

    2014-07-01

    Radon activity concentration in the soil air in the area of Faculty of Mathematics, Physics and Informatics (FMPI) in Bratislava, Slovak Republic, has been continuously monitored since 1994. Long-term measurements at a depth of 0.8 m and short-term measurements at a depth of 0.4 m show a high variability in radon activity concentrations in the soil. The analysis of the data confirms that regular daily changes in radon activity concentration in the soil air depend on the daily changes in atmospheric pressure. It was also found that the typical annual courses of the radon activity concentration in the soil air (with summer minima and winter maxima) were disturbed by mild winter and heavy summer precipitation. Influence of precipitation on the increase in the radon activity concentration in the soil air was observed at a depth of 0.4 m and subsequently at a depth of 0.8 m.

  10. Response of sugarcane to carbon dioxide enrichment and elevated air temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four sugarcane cultivars (CP 72-2086, CP 73-1547, CP 88-1508, and CP 80-1827) were grown in elongated temperature-gradient greenhouses (TGG) at ambient or elevated carbon dioxide (CO2) of 360 or 720 µmol CO2 mol-1 air (ppm, mole fraction basis), respectively. Elevated CO2 was maintained by injection...

  11. The effect of nutrient enrichment on the growth, nucleic acid concentrations, and elemental stoichiometry of coral reef macroalgae.

    PubMed

    Reef, Ruth; Pandolfi, John M; Lovelock, Catherine E

    2012-08-01

    The growth rate hypothesis (GRH) links growth rates with organism elemental stoichiometry. Support for the GRH was found for many animal species, but less so for plants. This is the first study to test the GRH in macroalgae. Tropical coral reef macroalgae from three lineages, Caulerpa serrulata (Chlorophyta), Laurencia intricata (Rhodophyta), and Sargassum polyphyllum (Phaeophyceae) were grown enriched with nitrogen or phosphorous and under control conditions at Heron Island on the Great Barrier Reef, Australia. Growth rate, photosynthesis, nucleic acid composition, and elemental stoichiometry were measured. Nutrient enrichment had positive effects on photosynthetic rates and on investment in RNA. However, growth rate was not correlated with either photosynthetic rates or RNA content; thus, we did not find support for the GRH in tropical macroalgae. Macroalgae, especially L. intricata, accumulated P to very high levels (>0.6% of dry weight). The growth rate response to tissue P concentrations was unimodal. Above 0.21%, P accumulation had negative effects on growth. Nitrogen was not stored, but evidence of futile cycling was observed. The capacity to store large amounts of P is probably an adaptation to the low and patchy nutrient environment of the tropical oceans.

  12. The effect of nutrient enrichment on the growth, nucleic acid concentrations, and elemental stoichiometry of coral reef macroalgae

    PubMed Central

    Reef, Ruth; Pandolfi, John M; Lovelock, Catherine E

    2012-01-01

    The growth rate hypothesis (GRH) links growth rates with organism elemental stoichiometry. Support for the GRH was found for many animal species, but less so for plants. This is the first study to test the GRH in macroalgae. Tropical coral reef macroalgae from three lineages, Caulerpa serrulata (Chlorophyta), Laurencia intricata (Rhodophyta), and Sargassum polyphyllum (Phaeophyceae) were grown enriched with nitrogen or phosphorous and under control conditions at Heron Island on the Great Barrier Reef, Australia. Growth rate, photosynthesis, nucleic acid composition, and elemental stoichiometry were measured. Nutrient enrichment had positive effects on photosynthetic rates and on investment in RNA. However, growth rate was not correlated with either photosynthetic rates or RNA content; thus, we did not find support for the GRH in tropical macroalgae. Macroalgae, especially L. intricata, accumulated P to very high levels (>0.6% of dry weight). The growth rate response to tissue P concentrations was unimodal. Above 0.21%, P accumulation had negative effects on growth. Nitrogen was not stored, but evidence of futile cycling was observed. The capacity to store large amounts of P is probably an adaptation to the low and patchy nutrient environment of the tropical oceans. PMID:22957199

  13. Photosynthetic acclimation to enriched CO{sub 2} concentrations in Pinus Ponderosa

    SciTech Connect

    Torres, M.P.

    1995-11-01

    By the middle of the 21st century earth`s ambient CO{sub 2} level is expected to increase two-fold ({approximately}350 umol/L). Higher levels of CO{sub 2} are expected to cause major changes in the morphological, physiological, and biochemical traits of the world`s vegetation. Therefore, we constructed an experiment designed to measure the long-term acclimation processes of Pinus Ponderosa. As a prominent forest conifer, Pinus Ponderosa is useful when assessing a large scale global carbon budget. Eighteen genetically variable families were exposed to 3 different levels of CO{sub 2} (350 umol/L, 525 umol/L, 700 umol/L), for three years. Acclimation responses were quantified by assays of photosynthetic rate, chlorophyll fluorescence, and chlorophyll pigment concentrations.

  14. Enrichment of anodic biofilm inoculated with anaerobic or aerobic sludge in single chambered air-cathode microbial fuel cells.

    PubMed

    Gao, Chongyang; Wang, Aijie; Wu, Wei-Min; Yin, Yalin; Zhao, Yang-Guo

    2014-09-01

    Aerobic sludge after anaerobic pretreatment and anaerobic sludge were separately used as inoculum to start up air-cathode single-chamber MFCs. Aerobic sludge-inoculated MFCs arrived at 0.27 V with a maximum power density of 5.79 W m(-3), while anaerobic sludge-inoculated MFCs reached 0.21 V with 3.66 W m(-3). Microbial analysis with DGGE profiling and high-throughput sequencing indicated that aerobic sludge contained more diverse bacterial populations than anaerobic sludge. Nitrospira species dominated in aerobic sludge, while anaerobic sludge was dominated by Desulfurella and Acidithiobacillus species. Microbial community structure and composition in anodic biofilms enriched, respectively from aerobic and anaerobic sludges tended gradually to be similar. Potentially exoelectrogenic Geobacter and Anaeromusa species, biofilm-forming Zoogloea and Acinetobacter species were abundant in both anodic biofilms. This study indicated that aerobic sludge performed better for MFCs startup, and the enrichment of anodic microbial consortium with different inocula but same substrate resulted in uniformity of functional microbial communities.

  15. Analysis of Mobile Source Air Toxics (MSATS)–Near-Road VOC and CarbonylConcentrations

    EPA Science Inventory

    This presentation examines data from a year-long study of measured near-road mobile source air toxic (MSAT) concentrations and compares these data with modeled 2005 National Air Toxic Assessment (NATA) results. Field study measurements were collected during a field campaign in ...

  16. EFFECTS OF METAL COMPONENTS IN CONCENTRATED AMBIENT AIR PARTICLES ON PULMONARY INJURY

    EPA Science Inventory

    EFFECTS OF METAL COMPONENTS IN CONCENTRATED AMBIENT AIR PARTICLES ON PULMONARY INJURY. Yuh-Chin Huang, Jackie Stonehuerner, Jackie Carter, Andrew J. Ghio, Robert B. Devlin. NHEERL, US EPA, RTP, NC.
    The mechanisms for cardiopulmonary morbidity associated with exposure to air po...

  17. The O{sub 2}-enriched air gasification of coal, plastics and wood in a fluidized bed reactor

    SciTech Connect

    Mastellone, Maria Laura; Zaccariello, Lucio; Santoro, Donato; Arena, Umberto

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer The effect of the O{sub 2} in the gasification stream of a BFB gasifier has been studied. Black-Right-Pointing-Pointer Main advantage of the O{sub 2}-enriched air is the increasing of the bed temperature. Black-Right-Pointing-Pointer No remarkable effects on tar reduction. Decreasing of recognized PAHs. Black-Right-Pointing-Pointer Gasification reactions completed inside the dense bed and splashing zone. Black-Right-Pointing-Pointer Polycondensation reactions occur mainly in the freeboard region. - Abstract: The effect of oxygen-enriched air during fluidized bed co-gasification of a mixture of coal, plastics and wood has been investigated. The main components of the obtained syngas were measured by means of on-line analyzers and a gas chromatograph while those of the condensate phase were off-line analysed by means of a gas chromatography-mass spectrometer (GC-MS). The characterization of condensate phase as well as that of the water used as scrubbing medium completed the performed diagnostics. The experimental results were further elaborated in order to provide material and substances flow analyses inside the plant boundaries. These analyses allowed to obtain the main substance distribution between solid, gaseous and condensate phases and to estimate the conversion efficiency of carbon and hydrogen but also to easily visualise the waste streams produced by the process. The process performance was then evaluated on the basis of parameters related to the conversion efficiency of fuels into valuable products (i.e. by considering tar and particulate as process losses) as well as those related to the energy recovery.

  18. Rapid Concentration and Molecular Enrichment Approach for Sensitive Detection of Escherichia coli and Shigella Species in Potable Water Samples ▿

    PubMed Central

    Maheux, Andrée F.; Bissonnette, Luc; Boissinot, Maurice; Bernier, Jean-Luc T.; Huppé, Vicky; Picard, François J.; Bérubé, Ève; Bergeron, Michel G.

    2011-01-01

    In this work, we used a rapid, simple, and efficient concentration-and-recovery procedure combined with a DNA enrichment method (dubbed CRENAME [concentration and recovery of microbial particles, extraction of nucleic acids, and molecular enrichment]), that we coupled to an Escherichia coli/Shigella-specific real-time PCR (rtPCR) assay targeting the tuf gene, to sensitively detect E. coli/Shigella in water. This integrated method was compared to U.S. Environmental Protection Agency (EPA) culture-based Method 1604 on MI agar in terms of analytical specificity, ubiquity, detection limit, and rapidity. None of the 179 non-E. coli/Shigella strains tested was detected by both methods, with the exception of Escherichia fergusonii, which was detected by the CRENAME procedure combined with the E. coli/Shigella-specific rtPCR assay (CRENAME + E. coli rtPCR). DNA from all 90 E. coli/Shigella strains tested was amplified by the CRENAME + E. coli rtPCR, whereas the MI agar method had limited ubiquity and detected only 65 (72.2%) of the 90 strains tested. In less than 5 h, the CRENAME + E. coli rtPCR method detected 1.8 E. coli/Shigella CFU whereas the MI agar method detected 1.2 CFU/100 ml of water in 24 h (95% confidence). Consequently, the CRENAME method provides an easy and efficient approach to detect as little as one Gram-negative E. coli/Shigella cell present in a 100-ml potable water sample. Coupled with an E. coli/Shigella-specific rtPCR assay, the entire molecular procedure is comparable to U.S. EPA Method 1604 on MI agar in terms of analytical specificity and detection limit but provides significant advantages in terms of speed and ubiquity. PMID:21764965

  19. Reference values for indoor air pollutant concentrations in new, residential buildings in Finland

    NASA Astrophysics Data System (ADS)

    Järnström, H.; Saarela, K.; Kalliokoski, P.; Pasanen, A.-L.

    Eight buildings, representing the present construction practice in Finland, were investigated to create numeric reference data for indoor air quality (IAQ) in new residential buildings. Low-emitting materials according to the "Finnish Classification of Building Materials" were used in all the buildings. The airborne volatile organic compounds (VOCs), formaldehyde, and ammonia concentrations as well as temperature, relative humidity, and the air exchange rate were determined in the newly finished buildings and after 6 and 12 months. Target values for the indoor air concentrations were not generally reached in newly finished buildings. The lowest concentration levels were measured in buildings with mechanical supply and exhaust air systems. Formaldehyde concentrations fulfilled best the target values. The TVOC concentration usually reached the S2/S3-class values within 6 months. However, the ammonia concentration remained above the S3 limit during the whole first year. The concentrations of ammonia and formaldehyde showed seasonal variations, i.e., higher concentrations were measured in summer. The concentrations of individual VOCs generally decreased most strongly during the first 6 months and the final mean concentration levels were generally less than 15 μg m -3. As the occupancy period got longer, the VOCs originating from the construction phase were increasingly replaced by new ones. Reference values based on means and on 95 percentiles are presented to facilitate interpretation of the results of measurements done to ensure that proper construction practices have been applied or to investigate IAQ problems.

  20. USING THE AIR QUALITY MODEL TO ANALYZE THE CONCENTRATIONS OF AIR TOXICS OVER THE CONTINENTAL U.S.

    EPA Science Inventory

    The U.S. Environmental Protection Agency is examining the concentrations and deposition of hazardous air pollutants (HAPs), which include a large number of chemicals, ranging from non reactive (i.e. carbon tetrachloride) to reactive (i.e. formaldehyde), exist in gas, aqueous, and...

  1. Erythritol-Enriched Air-Polishing Powder for the Surgical Treatment of Peri-Implantitis

    PubMed Central

    Taschieri, Silvio; Weinstein, Roberto

    2015-01-01

    Peri-implantitis represents a major complication that can compromise the success and survival of implant-supported rehabilitations. Both surgical and nonsurgical treatment protocols were proposed to improve clinical parameters and to treat implants affected by peri-implantitis. A systematic review of the literature was performed on electronic databases. The use of air-polishing powder in surgical treatment of peri-implantitis was investigated. A total of five articles, of different study designs, were included in the review. A meta-analysis could not be performed. The data from included studies reported a substantial benefit of the use of air-polishing powders for the decontamination of implant surface in surgical protocols. A case report of guided bone regeneration in sites with implants affected by peri-implantitis was presented. Surgical treatment of peri-implantitis, though demanding and not supported by a wide scientific literature, could be considered a viable treatment option if an adequate decontamination of infected surfaces could be obtained. PMID:26065025

  2. Erythritol-Enriched Air-Polishing Powder for the Surgical Treatment of Peri-Implantitis.

    PubMed

    Taschieri, Silvio; Weinstein, Roberto; Del Fabbro, Massimo; Corbella, Stefano

    2015-01-01

    Peri-implantitis represents a major complication that can compromise the success and survival of implant-supported rehabilitations. Both surgical and nonsurgical treatment protocols were proposed to improve clinical parameters and to treat implants affected by peri-implantitis. A systematic review of the literature was performed on electronic databases. The use of air-polishing powder in surgical treatment of peri-implantitis was investigated. A total of five articles, of different study designs, were included in the review. A meta-analysis could not be performed. The data from included studies reported a substantial benefit of the use of air-polishing powders for the decontamination of implant surface in surgical protocols. A case report of guided bone regeneration in sites with implants affected by peri-implantitis was presented. Surgical treatment of peri-implantitis, though demanding and not supported by a wide scientific literature, could be considered a viable treatment option if an adequate decontamination of infected surfaces could be obtained.

  3. Prospects for utilization of air liquefaction and enrichment system (ALES) propulsion in fully reusable launch vehicles

    NASA Technical Reports Server (NTRS)

    Bond, W. H.; Yi, A. C.

    1993-01-01

    A concept is shown for a fully reusable, earth to orbit launch vehicle with horizontal takeoff and landing, employing an air-turborocket for low speed and a rocket for high speed acceleration, both using LH2 fuel. The turborocket employs a modified liquid air cycle to supply the oxidizer. The rocket uses 90 percent pure LOX that is collected from the atmosphere, separated, and stored during operation of the turborocket from about Mach 2 to Mach 5 or 6. The takeoff weight and the thrust required at takeoff are markedly reduced by collecting the rocket oxidizer in-flight. The paper shows an approach and the corresponding technology needs for using ALES propulsion in a SSTO vehicle. Reducing the trajectory altitude at the end of collection reduces the wing area and increases payload. The use of state-of-the-art materials, such as graphite polyimide, is critical to meet the structure weight objective for SSTO. Configurations that utilize 'waverider' aerodynamics show great promise to reduce the vehicle weight.

  4. Concentrations in air of organobromine, organochlorine and organophosphate flame retardants in Toronto, Canada

    NASA Astrophysics Data System (ADS)

    Shoeib, Mahiba; Ahrens, Lutz; Jantunen, Liisa; Harner, Tom

    2014-12-01

    Concentrations of organobromine (BFRs), organochlorine (CFRs) and organophosphate esters flame retardants and plasticizers (PFRs) in air were monitored for over one year at an urban site in Toronto, Canada during 2010-2011. The mean value for polybrominated diphenyl ethers (BDEs) (gas + particle phase) was 38 pg/m3 with BDE-47 and BDE-99 as the dominant congeners. The mean concentrations in air for ∑non-BDE (BFRs and CFRs), was 9.6 pg/m3 - about four times lower than the BDEs. The brominated FRs: TBP-AE, BTBPE, EH-TBB, BEH-TEBP and the chlorinated syn- and anti-DP were detected frequently, ranging from 87% to 96%. Highest concentrations in air among all flame retardant classes were observed for the Σ-PFRs. The yearly mean concentration in air for ΣPFRs was 2643 pg/m3 with detection frequency higher than 80%. Except for TBP-AE and b- DBE-DBCH, non-BDEs (BFRs, CFRs and PFRs) were mainly associated with the particle phase. BDE concentrations in air were positively correlated with temperature indicating that volatilization from local sources was an important factor controlling levels in air. This correlation did not hold for most BFRs, CFRs and PFRs which were mainly on particles. For these compounds, air concentrations in Toronto are likely related to emissions from point sources and advective inputs. This study highlights the importance of urban air monitoring for FRs. Urban air can be considered a sentinel for detecting changes in the use and application of FRs in commercial products.

  5. LIF measurements of oxygen concentration gradients along flat and wavy air-water interfaces

    NASA Astrophysics Data System (ADS)

    Woodrow, Philip T., Jr.; Duke, Steve R.

    Instantaneous spatially-varying measurements of concentration gradients occurring during aeration for flat, stagnant air-water interfaces and for interfaces with mechanically-generated waves are presented. Measurements were obtained in a laboratory wave tank using a laser-induced fluorescence (LIF) technique that images planar oxygen concentration fields near air-water interfaces. Pulsed nitrogen laser light focused to a thin sheet induces the fluorescence of pyrene butyric acid (in micromolar concentration) in deoxygenated water. The PBA fluorescence is quenched by dissolved oxygen. A high-resolution CCD camera images in two dimensions the intensities of the fluorescence field, providing spatial measurements of oxygen concentration with magnification of 7 μm per pixel. The concentration fields, gradients, and boundary layer thicknesses along the flat and wavy air-water interfaces are quantified and compared to previous measurements associated with sheared gas-liquid interfaces and with wind-generated waves.

  6. Effect of cation enrichment on dipalmitoylphosphatidylcholine (DPPC) monolayers at the air-water interface.

    PubMed

    Adams, Ellen M; Casper, Clayton B; Allen, Heather C

    2016-09-15

    The effect of highly concentrated salt solutions of marine-relevant cations (Na(+), K(+), Mg(2+), and Ca(2+)) on Langmuir monolayers of dipalmitoylphosphatidylcholine (DPPC) was investigated by means of surface pressure-area isotherms, Brewster angle microscopy (BAM), and infrared reflection-absorption spectroscopy (IRRAS). It was found that monovalent cations and Mg(2+) have similar phase behavior, causing DPPC monolayers to expand, while Ca(2+) induces condensation. All cations disrupted the surface morphology at high cation concentration, resulting in decreased reflectivity from the monolayer. Monolayer refractive index was calculated from BAM image intensity in the liquid condensed phase and decreased with increasing cation concentration, which suggests that orientation of the alkyl chains change. Monovalent ions increase ordering of the alkyl chains, more than divalents, yet have little interaction with the DPPC headgroup. Mg(2+) induces gauche defects in the alkyl chain and increases headgroup hydration at low lipid coverage but increases chain ordering and dehydrates the headgroup at high lipid coverage. Ca(2+) orders alkyl chains and dehydrates the phosphate moiety, independent of lipid phase. At the highest salt concentration investigated, significant narrowing of the asymmetric PO2(-) vibrational mode occurs and is attributed to considerable dehydration of the DPPC headgroup. PMID:27322949

  7. Trend and climate signals in seasonal air concentration of organochlorine pesticides over the Great Lakes

    NASA Astrophysics Data System (ADS)

    Gao, Hong; Ma, Jianmin; Cao, Zuohao; Dove, Alice; Zhang, Lisheng

    2010-08-01

    Following worldwide bans or restrictions, the atmospheric level of many organochlorine pesticides (OCPs) over the Great Lakes exhibited a decreasing trend since the 1980s in various environmental compartments. Atmospheric conditions also influence variation and trend of OCPs. In the present study a nonparametric Mann-Kendall test with an additional process to remove the effect of temporal (serial) correlation was used to detect the temporal trend of OCPs in the atmosphere over the Great Lakes region and to examine the statistical significance of the trends. Using extended time series of measured air concentrations over the Great Lakes region from the Integrated Atmospheric Deposition Network, this study also revisits relationships between seasonal mean air concentration of OCPs and major climate variabilities in the Northern Hemisphere. To effectively extract climate signals from the temporal trend of air concentrations, we detrended air concentrations through removing their linear trend, which is driven largely by their respective half-lives in the atmosphere. The interannual variations of the extended time series show a good association with interannual climate variability, notably, the North Atlantic Oscillation (NAO) and the El Niño-Southern Oscillation. This study demonstrates that the stronger climate signals can be extracted from the detrended time series of air concentrations of some legacy OCPs. The detrended concentration time series also help to interpret, in addition to the connection with interannual variation of the NAO, the links between atmospheric concentrations of OCPs and decadal or interdecadal climate change.

  8. An assessment of ozone concentrations within and near the Lake Tahoe Air Basin

    NASA Astrophysics Data System (ADS)

    Dolislager, Leon J.; VanCuren, Richard; Pederson, James R.; Lashgari, Ash; McCauley, Eileen

    2012-01-01

    The Lake Tahoe Atmospheric Deposition Study (LTADS) was conducted by the Air Resources Board of the State of California (CARB) primarily to generate refined estimates of the atmospheric deposition of nitrogen, phosphorous, and particulate matter directly to Lake Tahoe, which straddles the border between the states of California and Nevada near Reno, Nevada. The enhanced air quality monitoring during LTADS also included ozone measurements, which yielded additional insights into atmospheric processes and the role of transport in determining ozone concentrations within the Lake Tahoe Air Basin. The Lake Tahoe Air Basin is located generally downwind of air basins with major emissions of ozone precursors (e.g., VOCs, NOx), capable of generating significant ozone concentrations. Furthermore, vegetation on the western slope of the Sierra Nevada contribute biogenic organic compounds to the air mass. Ozone concentrations within the Tahoe Basin infrequently exceed the local 1-h threshold set to protect forest health (0.08 ppm) and the California 8-h ambient air quality standard (0.070 ppm). A concern then is the potential contribution of regional emission sources to the ozone concentrations observed in the Tahoe Basin. The ozone data collected during LTADS helped to better characterize the relative contribution of local and regional pollution sources to ozone air quality within the Tahoe Basin. The data indicate potential 1- or 2-day intact transport on rare occasions but generally the mixing of the atmosphere over the Sierra Nevada disperses the anthropogenic ozone throughout the boundary layer, which is generally more than a kilometer or two deep during the day. The data analysis indicates that emissions from upwind air basins add to the atmospheric burden of ozone concentrations, raising the regional concentrations in the Sierra Nevada. Given the large background and upwind enhancements relative to the ambient air quality standards, the local contribution does not need to

  9. Sustained enhancement of photosynthesis in coffee trees grown under free-air CO2 enrichment conditions: disentangling the contributions of stomatal, mesophyll, and biochemical limitations.

    PubMed

    DaMatta, Fábio M; Godoy, Alice G; Menezes-Silva, Paulo E; Martins, Samuel C V; Sanglard, Lílian M V P; Morais, Leandro E; Torre-Neto, André; Ghini, Raquel

    2016-01-01

    Coffee (Coffea spp.), a globally traded commodity, is a slow-growing tropical tree species that displays an improved photosynthetic performance when grown under elevated atmospheric CO2 concentrations ([CO2]). To investigate the mechanisms underlying this response, two commercial coffee cultivars (Catuaí and Obatã) were grown using the first free-air CO2 enrichment (FACE) facility in Latin America. Measurements were conducted in two contrasting growth seasons, which were characterized by the high (February) and low (August) sink demand. Elevated [CO2] led to increases in net photosynthetic rates (A) in parallel with decreased photorespiration rates, with no photochemical limitations to A. The stimulation of A by elevated CO2 supply was more prominent in August (56% on average) than in February (40% on average). Overall, the stomatal and mesophyll conductances, as well as the leaf nitrogen and phosphorus concentrations, were unresponsive to the treatments. Photosynthesis was strongly limited by diffusional constraints, particularly at the stomata level, and this pattern was little, if at all, affected by elevated [CO2]. Relative to February, starch pools (but not soluble sugars) increased remarkably (>500%) in August, with no detectable alteration in the maximum carboxylation capacity estimated on a chloroplast [CO2] basis. Upregulation of A by elevated [CO2] took place with no signs of photosynthetic downregulation, even during the period of low sink demand, when acclimation would be expected to be greatest.

  10. Sustained enhancement of photosynthesis in coffee trees grown under free-air CO2 enrichment conditions: disentangling the contributions of stomatal, mesophyll, and biochemical limitations

    PubMed Central

    DaMatta, Fábio M.; Godoy, Alice G.; Menezes-Silva, Paulo E.; Martins, Samuel C.V.; Sanglard, Lílian M.V.P.; Morais, Leandro E.; Torre-Neto, André; Ghini, Raquel

    2016-01-01

    Coffee (Coffea spp.), a globally traded commodity, is a slow-growing tropical tree species that displays an improved photosynthetic performance when grown under elevated atmospheric CO2 concentrations ([CO2]). To investigate the mechanisms underlying this response, two commercial coffee cultivars (Catuaí and Obatã) were grown using the first free-air CO2 enrichment (FACE) facility in Latin America. Measurements were conducted in two contrasting growth seasons, which were characterized by the high (February) and low (August) sink demand. Elevated [CO2] led to increases in net photosynthetic rates (A) in parallel with decreased photorespiration rates, with no photochemical limitations to A. The stimulation of A by elevated CO2 supply was more prominent in August (56% on average) than in February (40% on average). Overall, the stomatal and mesophyll conductances, as well as the leaf nitrogen and phosphorus concentrations, were unresponsive to the treatments. Photosynthesis was strongly limited by diffusional constraints, particularly at the stomata level, and this pattern was little, if at all, affected by elevated [CO2]. Relative to February, starch pools (but not soluble sugars) increased remarkably (>500%) in August, with no detectable alteration in the maximum carboxylation capacity estimated on a chloroplast [CO2] basis. Upregulation of A by elevated [CO2] took place with no signs of photosynthetic downregulation, even during the period of low sink demand, when acclimation would be expected to be greatest. PMID:26503540

  11. Sustained enhancement of photosynthesis in coffee trees grown under free-air CO2 enrichment conditions: disentangling the contributions of stomatal, mesophyll, and biochemical limitations.

    PubMed

    DaMatta, Fábio M; Godoy, Alice G; Menezes-Silva, Paulo E; Martins, Samuel C V; Sanglard, Lílian M V P; Morais, Leandro E; Torre-Neto, André; Ghini, Raquel

    2016-01-01

    Coffee (Coffea spp.), a globally traded commodity, is a slow-growing tropical tree species that displays an improved photosynthetic performance when grown under elevated atmospheric CO2 concentrations ([CO2]). To investigate the mechanisms underlying this response, two commercial coffee cultivars (Catuaí and Obatã) were grown using the first free-air CO2 enrichment (FACE) facility in Latin America. Measurements were conducted in two contrasting growth seasons, which were characterized by the high (February) and low (August) sink demand. Elevated [CO2] led to increases in net photosynthetic rates (A) in parallel with decreased photorespiration rates, with no photochemical limitations to A. The stimulation of A by elevated CO2 supply was more prominent in August (56% on average) than in February (40% on average). Overall, the stomatal and mesophyll conductances, as well as the leaf nitrogen and phosphorus concentrations, were unresponsive to the treatments. Photosynthesis was strongly limited by diffusional constraints, particularly at the stomata level, and this pattern was little, if at all, affected by elevated [CO2]. Relative to February, starch pools (but not soluble sugars) increased remarkably (>500%) in August, with no detectable alteration in the maximum carboxylation capacity estimated on a chloroplast [CO2] basis. Upregulation of A by elevated [CO2] took place with no signs of photosynthetic downregulation, even during the period of low sink demand, when acclimation would be expected to be greatest. PMID:26503540

  12. Free-air CO{sub 2} enrichment for forests: Prototype development

    SciTech Connect

    Hendrey, G.; Strain, B.

    1994-04-01

    This paper presents details of a study that was done to assess the damage that elevated carbon dioxide has on forest ecosystems. Topics discussed include: elevated concentration of carbon dioxide can it be maintained at ground level; effects of wind variations; is there a problem with carbon dioxide and how serious is it; and can forests management strategies be altered to sustain forest productivity, health and diversity.

  13. Microclimatic Performance of a Free-Air Warming and CO2 Enrichment Experiment in Windy Wyoming, USA

    PubMed Central

    LeCain, Daniel; Smith, David; Morgan, Jack; Kimball, Bruce A.; Pendall, Elise; Miglietta, Franco

    2015-01-01

    In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO2) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO2 enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night) but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms-1 average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO2 had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO2. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming for much of the

  14. Modeling indoor air concentrations near emission sources in imperfectly mixed rooms.

    PubMed

    Furtaw, E J; Pandian, M D; Nelson, D R; Behar, J V

    1996-09-01

    Assessments of exposure to indoor air pollutants usually employ spatially well-mixed models which assume homogeneous concentrations throughout a building or room. However, practical experience and experimental data indicate that concentrations are not uniform in rooms containing point sources of emissions; concentrations tend to be greater in close proximity to the source than they are further from it. This phenomenon could account for the observation that "personal air" monitors frequently yield higher concentrations than nearby microenvironmental monitors (i.e., the so-called "personal cloud" effect). In this project, we systematically studied the concentrations of a tracer gas at various distances from its emission source in a controlled-environment, room-size chamber under a variety of ventilation conditions. Measured concentrations in the proximity of the source deviated significantly above the predictions of a conventional well-mixed single-compartment mass balance model. The deviation was found to be a function of distance from the source and total room air flow rate. At typical air flow rates, the average concentration at arm's length (approximately 0.4 meters) from the source exceeds the theoretical well-mixed concentration by a ratio of about 2:1. However, this ratio is not constant; the monitored concentration appears to vary randomly from near the theoretical value to several times above it. Concentration data were fitted to a two-compartment model with the source located in a small virtual compartment within the room compartment. These two compartments were linked with a stochastic air transfer rate parameter. The resulting model provides a more realistic simulation of exposure concentrations than does the well-mixed model for assessing exposure to emissions from active sources. Parameter values are presented for using the enhanced model in a variety of typical situations. PMID:8925388

  15. Leaf and canopy conductance in aspen and aspen-birch forests under free-air enrichment of carbon dioxide and ozone.

    PubMed

    Uddling, Johan; Teclaw, Ronald M; Pregitzer, Kurt S; Ellsworth, David S

    2009-11-01

    Increasing concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have the potential to affect tree physiology and structure, and hence forest feedbacks on climate. Here, we investigated how elevated concentrations of CO2 (+45%) and O3 (+35%), alone and in combination, affected conductance for mass transfer at the leaf and canopy levels in pure aspen (Populus tremuloides Michx.) and in mixed aspen and birch (Betula papyrifera Marsh.) forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). The study was conducted during two growing seasons, when steady-state leaf area index (L) had been reached after > 6 years of exposure to CO2- and O3-enrichment treatments. Canopy conductance (g(c)) was estimated from stand sap flux, while leaf-level conductance of sun leaves in the upper canopy was derived by three different and independent methods: sap flux and L in combination with vertical canopy modelling, leaf 13C discrimination methodology in combination with photosynthesis modelling and leaf-level gas exchange. Regardless of the method used, the mean values of leaf-level conductance were higher in trees growing under elevated CO2 and/or O3 than in trees growing in control plots, causing a CO2 x O3 interaction that was statistically significant (P < or = 0.10) for sap flux- and (for birch) 13C-derived leaf conductance. Canopy conductance was significantly increased by elevated CO2 but not significantly affected by elevated O3. Investigation of a short-term gap in CO2 enrichment demonstrated a +10% effect of transient exposure of elevated CO2-grown trees to ambient CO2 on g(c). All treatment effects were similar in pure aspen and mixed aspen-birch communities. These results demonstrate that short-term primary stomatal closure responses to elevated CO2 and O3 were completely offset by long-term cumulative effects of these trace gases on tree and stand structure in determining canopy- and leaf-level conductance in

  16. Leaf and canopy conductance in aspen and aspen-birch forests under free-air enrichment of carbon dioxide and ozone.

    PubMed

    Uddling, Johan; Teclaw, Ronald M; Pregitzer, Kurt S; Ellsworth, David S

    2009-11-01

    Increasing concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have the potential to affect tree physiology and structure, and hence forest feedbacks on climate. Here, we investigated how elevated concentrations of CO2 (+45%) and O3 (+35%), alone and in combination, affected conductance for mass transfer at the leaf and canopy levels in pure aspen (Populus tremuloides Michx.) and in mixed aspen and birch (Betula papyrifera Marsh.) forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). The study was conducted during two growing seasons, when steady-state leaf area index (L) had been reached after > 6 years of exposure to CO2- and O3-enrichment treatments. Canopy conductance (g(c)) was estimated from stand sap flux, while leaf-level conductance of sun leaves in the upper canopy was derived by three different and independent methods: sap flux and L in combination with vertical canopy modelling, leaf 13C discrimination methodology in combination with photosynthesis modelling and leaf-level gas exchange. Regardless of the method used, the mean values of leaf-level conductance were higher in trees growing under elevated CO2 and/or O3 than in trees growing in control plots, causing a CO2 x O3 interaction that was statistically significant (P < or = 0.10) for sap flux- and (for birch) 13C-derived leaf conductance. Canopy conductance was significantly increased by elevated CO2 but not significantly affected by elevated O3. Investigation of a short-term gap in CO2 enrichment demonstrated a +10% effect of transient exposure of elevated CO2-grown trees to ambient CO2 on g(c). All treatment effects were similar in pure aspen and mixed aspen-birch communities. These results demonstrate that short-term primary stomatal closure responses to elevated CO2 and O3 were completely offset by long-term cumulative effects of these trace gases on tree and stand structure in determining canopy- and leaf-level conductance in

  17. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... concentration (DAC) values given in appendices A and C of this part shall be used in the control of occupational... 10 Energy 4 2012-01-01 2012-01-01 false Concentrations of radioactive material in air. 835.209 Section 835.209 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal...

  18. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... concentration (DAC) values given in appendices A and C of this part shall be used in the control of occupational... 10 Energy 4 2011-01-01 2011-01-01 false Concentrations of radioactive material in air. 835.209 Section 835.209 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal...

  19. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... concentration (DAC) values given in appendices A and C of this part shall be used in the control of occupational... 10 Energy 4 2013-01-01 2013-01-01 false Concentrations of radioactive material in air. 835.209 Section 835.209 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal...

  20. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... concentration (DAC) values given in appendices A and C of this part shall be used in the control of occupational... 10 Energy 4 2014-01-01 2014-01-01 false Concentrations of radioactive material in air. 835.209 Section 835.209 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal...

  1. COMPARISON OF MOLD CONCENTRATIONS IN INDOOR AND OUTDOOR AIR SAMPLED SIMULTANEOUSLY AND THEN QUANTIFIED BY MSQPCR

    EPA Science Inventory

    Mold specific quantitative PCR (MSQPCR) was used to measure the concentrations of the 36 mold species in indoor and outdoor air samples that were taken simultaneously for 48 hours in and around 17 homes in Cincinnati, Ohio. The total spore concentrations of 353 per m3...

  2. Xylem anatomical responses of Vaccinium myrtillus exposed to air CO2 enrichment and soil warming at treeline

    NASA Astrophysics Data System (ADS)

    Anadon-Rosell, Alba; Fonti, Patrick; Dawes, Melissa; von Arx, Georg

    2016-04-01

    Plant life at treeline is limited by harsh growth conditions. In this study we used nine years of free air CO2 enrichment (+200 ppm from 2001 to 2009) and six years of soil warming (+4 °C from 2007 to 2012) at a treeline experimental site in the Swiss Alps to investigate xylem anatomical responses of Vaccinium myrtillus, a co-dominant dwarf shrub in many treeline communities. Our aim was to identify whether the release from limiting growth conditions induced adjustments of the water conductive and storage tissues. High-resolution images of wood anatomical microsections from the stem base of 40 individuals were captured with a digital camera mounted on a microscope. We used the specialized image analysis tool ROXAS to quantify size, density, grouping patterns, and potential hydraulic conductivity of vessels. In addition, we measured the abundance and distribution of ray parenchyma. Our preliminary results show that CO2 enrichment and soil warming induced contrasting anatomical responses. In the last years of the CO2 enhancement vessels were larger, whereas soil warming induced an immediate reduction of vessel size. Moreover, larger vessels were found when V. myrtillus was in cohabitation with pine as opposed to larch. Results for ray parenchyma measurements did not show clear trends, although warming seemed to have a slightly positive effect on the fraction of uniseriate vs. multiseriate rays. These results suggest that release from the growth limiting factors can result in contrasting and partially lagged responses in the hydraulic system with little impact on the storage tissues. In addition, the overstory species seem to play a key role on the anatomy of V. myrtillus at treeline.

  3. Prevalence and serogroup diversity of Salmonella for broiler neck skin, whole carcass rinse, and whole carcass enrichment sampling methodologies following air or immersion chilling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to evaluate neck skin (NS), whole carcass rinse (WCR), and whole carcass enrichment (WCE) sampling procedures for Salmonella isolation and serogroup from the same broiler carcass following either air or immersion chilling. Commercially processed and eviscerated broiler ...

  4. Demonstration of oxygen-enriched air staging at Owens-Brockway glass containers. Quarterly technical progress report for the period August 1, 1996--October 31, 1996

    SciTech Connect

    Rue, D.; Abbasi, H.

    1997-03-01

    The objective of the program is to demonstrate the use of a previously developed combustion modification technology to reduce NO, emissions from sideport regenerative container glass melters. This technology, known as oxygen-enriched air staging (OEAS), has been demonstrated, and is now being commercialized for endport container glass furnaces. This report focuses on full furnace parametric and long-term testing.

  5. Free-air CO2 enrichment (face): model analysis of gaseous dispersion arrays for studying rising atmospheric CO2 effects on vegetation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atmospheric carbon dioxide (CO2) has risen from about 280 to 380 micromol/mol since the beginning of the industrial revolution due mainly to burning of fossil fuels. Free-Air CO2 Enrichment (FACE) arrays have been devised with large areas and undisturbed aerial conditions that allow secondary soil o...

  6. High arsenic concentrations and enriched sulfur and oxygen isotopes in a fractured-bedrock ground-water system

    USGS Publications Warehouse

    Lipfert, G.; Sidle, W.C.; Reeve, A.S.; Ayuso, R.A.; Boyce, A.J.

    2007-01-01

    Ground water with high arsenic concentrations (up to 26.6????mol L- 1) has sulfate enriched in 34S and 18O in the fractured-bedrock, ground-water system of the Kelly's Cove watershed, Northport, Maine, USA. The ranges of sulfur and oxygen isotope values in aqueous sulfate, ??34S[SO4] and ??18O[SO4], at the Kelly's Cove watershed are + 3.4 to + 4.9??? and - 2.0 to + 6.7???, respectively. These isotope values are strikingly similar to those of the Goose River, Maine watershed which has ??34S[SO4] and ??18O[SO4] ranges of + 3.7 to + 4.6 ??? and - 2.6 to + 7.5???, respectively. In both systems, high arsenic concentrations occur with high ??34S[SO4] and ??18O[SO4] values, yet redox conditions and underlying rock types are quite different. The isotope values of sulfide minerals, ??34S[min], from four bedrock cores vary over short distances and range from - 5.1 to + 7.5???. The ??34S[SO4] values are controlled by the ??34S[min] values with minor input of atmospheric SO4. The much narrower range in ??34S[SO4] values than ??34S[min] values is probably due to sufficient ground-water mixing at a scale greater than the ??34S[min] variability. The ??34S[SO4] values are about 2??? higher than the average ??34S[min] value and fall within the range of ??34S[min] values, indicating only minor fractionation due to bacterial reduction of SO4. The highest ??18O[SO4] values were measured in the downgradient, confined, arsenic-rich ground water. High ??18O[SO4] values there cannot be due to aeration by atmospheric oxygen, but may arise from reoxidation of reduced SO4 products. The enrichment factors of ??18O in SO4 compared to H2O, + 7.2 to + 15.5???, in the Kelly's Cove ground water and the negligible 34S enrichment is very similar to those derived from experimental data of anaerobic sulfide oxidation in the presence of Mn and Fe oxides. Sea level at the Kelly's Cove watershed was approximately 80??m above present sea level about 13 000??years before present, imposing reducing

  7. Historical Occupational Trichloroethylene Air Concentrations Based on Inspection Measurements From Shanghai, China

    PubMed Central

    Friesen, Melissa C.; Locke, Sarah J.; Chen, Yu-Cheng; Coble, Joseph B.; Stewart, Patricia A.; Ji, Bu-Tian; Bassig, Bryan; Lu, Wei; Xue, Shouzheng; Chow, Wong-Ho; Lan, Qing; Purdue, Mark P.; Rothman, Nathaniel; Vermeulen, Roel

    2015-01-01

    Purpose: Trichloroethylene (TCE) is a carcinogen that has been linked to kidney cancer and possibly other cancer sites including non-Hodgkin lymphoma. Its use in China has increased since the early 1990s with China’s growing metal, electronic, and telecommunications industries. We examined historical occupational TCE air concentration patterns in a database of TCE inspection measurements collected in Shanghai, China to identify temporal trends and broad contrasts among occupations and industries. Methods: Using a database of 932 short-term, area TCE air inspection measurements collected in Shanghai worksites from 1968 through 2000 (median year 1986), we developed mixed-effects models to evaluate job-, industry-, and time-specific TCE air concentrations. Results: Models of TCE air concentrations from Shanghai work sites predicted that exposures decreased 5–10% per year between 1968 and 2000. Measurements collected near launderers and dry cleaners had the highest predicted geometric means (GM for 1986 = 150–190mg m−3). The majority (53%) of the measurements were collected in metal treatment jobs. In a model restricted to measurements in metal treatment jobs, predicted GMs for 1986 varied 35-fold across industries, from 11mg m−3 in ‘other metal products/repair’ industries to 390mg m–3 in ‘ships/aircrafts’ industries. Conclusions: TCE workplace air concentrations appeared to have dropped over time in Shanghai, China between 1968 and 2000. Understanding differences in TCE concentrations across time, occupations, and industries may assist future epidemiologic studies in China. PMID:25180291

  8. Indoor air polychlorinated biphenyl concentrations in three communities along the Upper Hudson River, New York.

    PubMed

    Wilson, Lloyd R; Palmer, Patrick M; Belanger, Erin E; Cayo, Michael R; Durocher, Lorie A; Hwang, Syni-An A; Fitzgerald, Edward F

    2011-10-01

    Indoor air polychlorinated biphenyl (PCB) concentrations were measured in upstate New York as part of a nonoccupational exposure investigation. The adjacent study communities contain numerous sites of current and former PCB contamination, including two capacitor-manufacturing facilities. Indoor air PCB concentrations in the study area homes were not significantly different than in the comparison area homes. Total PCB concentrations in the study area homes ranged from 0.3 to 114.3 ng/m(3) (median 7.9). For the comparison area homes, concentrations ranged from 0.3 to 233.3 ng/m(3) (median 6.8). No correlations were found between PCB concentrations in indoor and outdoor air, with indoor concentrations generally 20 times higher than outdoor concentrations. Of the home characteristics cataloged, the presence of fluorescent lights was significantly associated with total PCB concentration in the study area only. The indoor PCB concentrations measured in this study are similar to those in other communities with known PCB-contaminated sites and similar to levels reported in other locations from the northeastern United States. PMID:21136249

  9. Air-vegetation exchange of SOCs as a control of atmospheric concentrations and residence times

    SciTech Connect

    Hornbuckle, K.C.; Eisenreich, S.J.

    1994-12-31

    Semi-volatile organic compounds (SOCs) such as the polychlorinated biphenyls exhibit seasonal maxima in atmospheric concentrations with highest values in the warm summer. This generally believed to result from the effect of temperature on SOC vapor pressure with direct and important implications to global transport. The authors have conducted a series of field experiments whereby air samples were collected above an ombrotrophic, forested bog in northern MN at a frequency of 6 day{sup {minus}1} during the fall, winter, spring and summer. Samples of Sphagnum moss and other vegetation were also collected on each occasion. All samples were analyzed for PCBs, low MW PAHs, gaseous hydrocarbons and selected pesticides. Meteorological and soils data were collected during all experiments (air and soil temperature, wind direction and velocity, RH). Diurnal concentration data, air-plant and air-soil partition coefficients and probable mechanisms and kinetics of SOC-plant interactions will be presented.

  10. Modeling the Concentrations of On-Road Air Pollutants in Southern California

    PubMed Central

    Li, Lianfa; Wu, Jun; Hudda, Neelakshi; Sioutas, Constantinos; Fruin, Scott A.; Delfino, Ralph J.

    2014-01-01

    High concentrations of air pollutants on roadways, relative to ambient concentrations, contribute significantly to total personal exposure. Estimation of these exposures requires measurements or prediction of roadway concentrations. Our study develops, compares and evaluates linear regression and non-linear generalized additive models (GAMs) to estimate on-road concentrations of four key air pollutants, particle-bound polycyclic aromatic hydrocarbons (PB-PAH), particle number count (PNC), nitrogen oxides (NOx), and particulate matter with diameter <2.5 μm (PM2.5) using traffic, meteorology, and elevation variables. Critical predictors included wind speed and direction for all the pollutants, traffic-related variables for PB-PAH, PNC, and NOx, and air temperatures and relative humidity for PM2.5. GAMs explained 50%, 55%, 46%, and 71% of the variance for log or square-root transformed concentrations of PB-PAH, PNC, NOx, and PM2.5 respectively, an improvement of 5 to over 15% over the linear models. Accounting for temporal autocorrelation in the GAMs further improved the prediction, explaining 57-89% of the variance. We concluded that traffic and meteorological data are good predictors in estimating on-road traffic-related air pollutant concentrations and GAMs perform better for non-linear variables, such as meteorological parameters. PMID:23859442

  11. BIFoR FACE: A Free-Air Carbon Dioxide Enrichment (FACE) facility in old-growth temperate deciduous woodland

    NASA Astrophysics Data System (ADS)

    MacKenzie, Rob; Thomas, Rick; Ellsworth, David; Hemming, Debbie; Crous, Kristine; Blaen, Phillip; Poynter, Alex; Blenkhorn, Daniel; Pope, Francis

    2016-04-01

    The Birmingham Institute of Forest research (BIFoR) focuses on fundamental physical, biological, ecological, social and cultural research of direct relevance to forested landscapes worldwide. A core platform for BIFoR is a Free-Air Carbon Dioxide Enrichment (FACE) facility, with which we study the ten-year response of a mature temperate deciduous forest ecosystem to a 150-ppmv step-change in atmospheric [CO2]. BIFoR FACE is being established in Mill Haft, a mature (~150 year-old) oak (Quercus robur) and hazel (Corylus avellana) coppice-with-standards woodland in central England, UK. The facility enables elevated CO2 (eCO2) treatments to be introduced in 30 m diameter rings (3 treatment plots, 3 fully-replicated control plots, and 3 unmodified ambient controls). Primary research questions focus on carbon uptake and storage, corresponding nutrient limitations, and biodiversity and ecosystem responses to elevated CO2. Here we describe the facility and experimental design, and present baseline data collected through the growing season of 2015. These data include: biophysical tree properties; atmospheric CO2/H2O fluxes; airborne and ground laser scatterometry; leaf area index; geophysical survey data; canopy phenology; soil and water chemical and physical properties; and invertebrate surveys. Data from an intensive campaign conducted during august 2015 are also shown, including in- and above- canopy characterisation of biogenic VOCs using a Proton Transfer Reaction Mass Spectrometer, aerosol loading including bioaerosols, and air quality. Further campaign results are presented from leaf level photosynthetic carbon-dioxide response curve (A/Ci) performed at different canopy heights on oak trees, and on the dominant understory species - hazel and sycamore (Acer pseudoplatanus) across the site. BIFoR FACE is intended to be an international facility for forest science - ideas for collaborations are encouraged. Please see http

  12. Effects of the Deregulation on the Concentration of the Brazilian Air Transportation Industry

    NASA Technical Reports Server (NTRS)

    Guterres, Marcelo Xavier; Muller, Carlos

    2003-01-01

    This paper addresses the effects of the deregulation of the Brazilian air transportation industry in terms of the concentration of the market. We will show some metrics that are commonly used to study the concentration of the industry. This paper uses the Herfindhal- Hirschman Index. This index tends to zero in the competitive scenario, with a large number of small firms, and to one in case of a monopolistic scenario. The paper analyses the dynamics of the concentration of the Brazilian domestic air transportation market, in order to evaluate the effects of deregulation. We conclude that the Brazilian market presents oligopoly characteristics and aspects in its current structure that maintain the market concentrated in spite of the Deregulation measures adopted by the aeronautical authority. Keywords: Herfindhal-Hirschman Index, concentration, Deregulation

  13. Effect of outside air ventilation rate on VOC concentrations and emissions in a call center

    SciTech Connect

    Hodgson, A.T.; Faulkner, D.; Sullivan, D.P.; DiBartolomeo, D.L.; Russell, M.L.; Fisk, W.J.

    2002-01-01

    A study of the relationship between outside air ventilation rate and concentrations of VOCs generated indoors was conducted in a call center. Ventilation rates were manipulated in the building's four air handling units (AHUs). Concentrations of VOCs in the AHU returns were measured on 7 days during a 13-week period. Indoor minus outdoor concentrations and emission factors were calculated. The emission factor data was subjected to principal component analysis to identify groups of co-varying compounds based on source type. One vector represented emissions of solvents from cleaning products. Another vector identified occupant sources. Direct relationships between ventilation rate and concentrations were not observed for most of the abundant VOCs. This result emphasizes the importance of source control measures for limiting VOC concentrations in buildings.

  14. Influence of indoor air conditions on radon concentration in a detached house.

    PubMed

    Akbari, Keramatollah; Mahmoudi, Jafar; Ghanbari, Mahdi

    2013-02-01

    Radon is released from soil and building materials and can accumulate in residential buildings. Breathing radon and radon progeny for extended periods hazardous to health and can lead to lung cancer. Indoor air conditions and ventilation systems strongly influence indoor radon concentrations. This paper focuses on effects of air change rate, indoor temperature and relative humidity on indoor radon concentrations in a one family detached house in Stockholm, Sweden. In this study a heat recovery ventilation system unit was used to control the ventilation rate and a continuous radon monitor (CRM) was used to measure radon levels. FLUENT, a computational fluid dynamics (CFD) software package was used to simulate radon entry into the building and air change rate, indoor temperature and relative humidity effects using a numerical approach. The results from analytical solution, measurements and numerical simulations showed that air change rate, indoor temperature and moisture had significant effects on indoor radon concentration. Increasing air change rate reduces radon level and for a specific air change rate (in this work Ach = 0.5) there was a range of temperature and relative humidity that minimized radon levels. In this case study minimum radon levels were obtained at temperatures between 20 and 22 °C and a relative humidity of 50-60%.

  15. Influence of indoor air conditions on radon concentration in a detached house.

    PubMed

    Akbari, Keramatollah; Mahmoudi, Jafar; Ghanbari, Mahdi

    2013-02-01

    Radon is released from soil and building materials and can accumulate in residential buildings. Breathing radon and radon progeny for extended periods hazardous to health and can lead to lung cancer. Indoor air conditions and ventilation systems strongly influence indoor radon concentrations. This paper focuses on effects of air change rate, indoor temperature and relative humidity on indoor radon concentrations in a one family detached house in Stockholm, Sweden. In this study a heat recovery ventilation system unit was used to control the ventilation rate and a continuous radon monitor (CRM) was used to measure radon levels. FLUENT, a computational fluid dynamics (CFD) software package was used to simulate radon entry into the building and air change rate, indoor temperature and relative humidity effects using a numerical approach. The results from analytical solution, measurements and numerical simulations showed that air change rate, indoor temperature and moisture had significant effects on indoor radon concentration. Increasing air change rate reduces radon level and for a specific air change rate (in this work Ach = 0.5) there was a range of temperature and relative humidity that minimized radon levels. In this case study minimum radon levels were obtained at temperatures between 20 and 22 °C and a relative humidity of 50-60%. PMID:23159846

  16. The effects of forced air flow and oxygen concentration on flammability, smoke density, and pyrolytic toxicity

    NASA Technical Reports Server (NTRS)

    Sauers, D. G.

    1976-01-01

    The question is posed whether forced air flow should be incorporated into flammability tests as a relevant variable. A test apparatus is described which permits tests to be conducted on small test specimens in a forced flow which is (continuously) variable over flow velocities from zero to 300 feet per minute (1.52 m/s). The effects of air-flow rate and oxygen concentration on flame propagation rate, maximum smoke density, and pyrolytic product toxicity were measured for a single material and were statistically evaluated. Regression analysis was used to graph the resulting relationships. It is concluded that air velocity is an important variable for laboratory flammability testing.

  17. N2 fixation and cycling in Alnus glutinosa, Betula pendula and Fagus sylvatica woodland exposed to free air CO2 enrichment.

    PubMed

    Millett, Jonathan; Godbold, Douglas; Smith, Andrew R; Grant, Helen

    2012-06-01

    We measured the effect of elevated atmospheric CO(2) on atmospheric nitrogen (N(2)) fixation in the tree species Alnus glutinosa growing in monoculture or in mixture with the non-N(2)-fixing tree species Betula pendula and Fagus sylvatica. We addressed the hypotheses that (1) N(2) fixation in A. glutinosa will increase in response to increased atmospheric CO(2) concentrations, when growing in monoculture, (2) the impact of elevated CO(2) on N(2) fixation in A. glutinosa is the same in mixture and in monoculture and (3) the impacts of elevated CO(2) on N cycling will be evident by a decrease in leaf δ(15)N and by the soil-leaf enrichment factor (EF), and that these impacts will not differ between mixed and single species stands. Trees were grown in a forest plantation on former agricultural fields for four growing seasons, after which the trees were on average 3.8 m tall and canopy closure had occurred. Atmospheric CO(2) concentrations were maintained at either ambient or elevated (by 200 ppm) concentrations using a free-air CO(2) enrichment (FACE) system. Leaf δ(15)N was measured and used to estimate the amount (N(dfa)) and proportion (%N(dfa)) of N derived from atmospheric fixation. On average, 62% of the N in A. glutinosa leaves was from fixation. The %N(dfa) and N(dfa) for A. glutinosa trees in monoculture did not increase under elevated CO(2), despite higher growth rates. However, N(2) fixation did increase for trees growing in mixture, despite the absence of significant growth stimulation. There was evidence that fixed N(2) was transferred from A. glutinosa to F. sylvatica and B. pendula, but no evidence that this affected their CO(2) response. The results of this study show that N(2) fixation in A. glutinosa may be higher in a future elevated CO(2) world, but that this effect will only occur where the trees are growing in mixed species stands.

  18. Sex differences in panic-relevant responding to a 10% carbon dioxide-enriched air biological challenge.

    PubMed

    Nillni, Yael I; Berenz, Erin C; Rohan, Kelly J; Zvolensky, Michael J

    2012-01-01

    The current study examined sex differences in psychological (i.e., self-reported anxiety, panic symptoms, and avoidance) and physiological (i.e., heart rate and skin conductance level) response to, and recovery from, a laboratory biological challenge. Participants were a community-recruited sample of 128 adults (63.3% women; M(age)=23.2 years, SD=8.9) who underwent a 4-min 10% CO(2)-enriched air biological challenge. As predicted, women reported more severe physical panic symptoms and avoidance (i.e., less willingness to participate in another challenge) and demonstrated increased heart rate as compared to men above and beyond the variance accounted for by other theoretically relevant variables (recent panic attack history, neuroticism, and anxiety sensitivity). Additionally, women demonstrated a faster rate of recovery with respect to heart rate compared to men. These results are in line with literature documenting sex-specific differences in panic psychopathology, and results are discussed in the context of possible mechanisms underlying sex differences in panic vulnerability.

  19. An indica rice genotype showed a similar yield enhancement to that of hybrid rice under free air carbon dioxide enrichment.

    PubMed

    Zhu, Chunwu; Xu, Xi; Wang, Dan; Zhu, Jianguo; Liu, Gang

    2015-07-31

    Although the rice growth response to FACE (free-air CO2 enrichment) has been widely studied and is considered important within the scientific community, few studies have attempted to examine the effects of FACE on the yield of indica rice, which is typically the parent of indica hybrids in China. The effects of FACE on the yield, yield components, biomass, N uptake and leaf photosynthesis of Yangdao 6 Hao (an indica rice) in China were examined over 2 years. The grain yield increased over 30%, the panicle number increased 12.4% on average, and the spikelet number per panicle also showed an average increase of 8.2% at elevated CO2. FACE caused a significant enhancement in both the filled spikelet percentage (+5.9%) and the individual grain weight (+3.0%). Compared with three prior FACE studies on rice, a similar enhancement of yield in hybrid indica was shown under FACE, with much a higher value than for the japonica rice cultivar (approximately + 13%) because of indica's stronger sink generation and N uptake capacity, which help coordinate the C/N balance to avoid photosynthetic acclimation. The high enhancement of the indica rice yield under FACE holds promise for improved cultivar selection for future food security.

  20. An indica rice genotype showed a similar yield enhancement to that of hybrid rice under free air carbon dioxide enrichment

    NASA Astrophysics Data System (ADS)

    Zhu, Chunwu; Xu, Xi; Wang, Dan; Zhu, Jianguo; Liu, Gang

    2015-07-01

    Although the rice growth response to FACE (free-air CO2 enrichment) has been widely studied and is considered important within the scientific community, few studies have attempted to examine the effects of FACE on the yield of indica rice, which is typically the parent of indica hybrids in China. The effects of FACE on the yield, yield components, biomass, N uptake and leaf photosynthesis of Yangdao 6 Hao (an indica rice) in China were examined over 2 years. The grain yield increased over 30%, the panicle number increased 12.4% on average, and the spikelet number per panicle also showed an average increase of 8.2% at elevated CO2. FACE caused a significant enhancement in both the filled spikelet percentage (+5.9%) and the individual grain weight (+3.0%). Compared with three prior FACE studies on rice, a similar enhancement of yield in hybrid indica was shown under FACE, with much a higher value than for the japonica rice cultivar (approximately + 13%) because of indica’s stronger sink generation and N uptake capacity, which help coordinate the C/N balance to avoid photosynthetic acclimation. The high enhancement of the indica rice yield under FACE holds promise for improved cultivar selection for future food security.

  1. An indica rice genotype showed a similar yield enhancement to that of hybrid rice under free air carbon dioxide enrichment.

    PubMed

    Zhu, Chunwu; Xu, Xi; Wang, Dan; Zhu, Jianguo; Liu, Gang

    2015-01-01

    Although the rice growth response to FACE (free-air CO2 enrichment) has been widely studied and is considered important within the scientific community, few studies have attempted to examine the effects of FACE on the yield of indica rice, which is typically the parent of indica hybrids in China. The effects of FACE on the yield, yield components, biomass, N uptake and leaf photosynthesis of Yangdao 6 Hao (an indica rice) in China were examined over 2 years. The grain yield increased over 30%, the panicle number increased 12.4% on average, and the spikelet number per panicle also showed an average increase of 8.2% at elevated CO2. FACE caused a significant enhancement in both the filled spikelet percentage (+5.9%) and the individual grain weight (+3.0%). Compared with three prior FACE studies on rice, a similar enhancement of yield in hybrid indica was shown under FACE, with much a higher value than for the japonica rice cultivar (approximately + 13%) because of indica's stronger sink generation and N uptake capacity, which help coordinate the C/N balance to avoid photosynthetic acclimation. The high enhancement of the indica rice yield under FACE holds promise for improved cultivar selection for future food security. PMID:26228872

  2. The effects of free-air CO₂ enrichment (FACE) on carbon and nitrogen accumulation in grains of rice (Oryza sativa L.).

    PubMed

    Zhang, Guoyou; Sakai, Hidemitsu; Tokida, Takeshi; Usui, Yasuhiro; Zhu, Chunwu; Nakamura, Hirofumi; Yoshimoto, Mayumi; Fukuoka, Minehiko; Kobayashi, Kazuhiko; Hasegawa, Toshihiro

    2013-08-01

    Rising atmospheric CO₂ concentrations will probably increase rice (Oryza sativa L.) yield but decrease grain nitrogen (GN) concentration. Grains attached to different positions in the panicles differ greatly in weight and quality, but their responses to elevated CO₂ (e[CO₂]) are poorly understood, which limits our understanding of the mechanisms of yield enhancement and quality degradation. Thus a free-air CO₂ enrichment experiment was conducted to examine the effects of e[CO₂] on grain mass (GM), grain carbon (GC), and GN accumulation in the spikelets attached to the upper primary rachis branch (superior spikelets; SS) and those attached to the lower secondary rachis (inferior spikelets; IS). e[CO₂] stimulated the rice yield by 13% but decreased the N concentration in the panicle by 7% when averaged over two levels of N fertilizations (P < 0.01). The responses of SS and IS to e[CO₂] were different particularly under higher N supply. For SS, e[CO₂] decreased GN by 24% (P < 0.01) but did not affect GM. For IS, e[CO₂] increased GM by 13% (P < 0.05) but GN was not affected. The reduction of GN due to e[CO₂] started to appear at the beginning of grain filling. These results suggest that future [CO₂] levels probably stimulate the grain growth of IS, most of which are not marketable due to limited size, at the expense of GN reduction in SS. Translocation of N from SS to IS may be a possible mechanism for reduction in GN of SS. This may degrade the grain quality of marketable rice under e[CO₂]. PMID:23918962

  3. The effects of free-air CO2 enrichment (FACE) on carbon and nitrogen accumulation in grains of rice (Oryza sativa L.)

    PubMed Central

    Zhu, Chunwu; Hasegawa, Toshihiro

    2013-01-01

    Rising atmospheric CO2 concentrations will probably increase rice (Oryza sativa L.) yield but decrease grain nitrogen (GN) concentration. Grains attached to different positions in the panicles differ greatly in weight and quality, but their responses to elevated CO2 (e[CO2]) are poorly understood, which limits our understanding of the mechanisms of yield enhancement and quality degradation. Thus a free-air CO2 enrichment experiment was conducted to examine the effects of e[CO2] on grain mass (GM), grain carbon (GC), and GN accumulation in the spikelets attached to the upper primary rachis branch (superior spikelets; SS) and those attached to the lower secondary rachis (inferior spikelets; IS). e[CO2] stimulated the rice yield by 13% but decreased the N concentration in the panicle by 7% when averaged over two levels of N fertilizations (P < 0.01). The responses of SS and IS to e[CO2] were different particularly under higher N supply. For SS, e[CO2] decreased GN by 24% (P < 0.01) but did not affect GM. For IS, e[CO2] increased GM by 13% (P < 0.05) but GN was not affected. The reduction of GN due to e[CO2] started to appear at the beginning of grain filling. These results suggest that future [CO2] levels probably stimulate the grain growth of IS, most of which are not marketable due to limited size, at the expense of GN reduction in SS. Translocation of N from SS to IS may be a possible mechanism for reduction in GN of SS. This may degrade the grain quality of marketable rice under e[CO2]. PMID:23918962

  4. Preliminary assessment of BTEX concentrations in indoor air of residential buildings and atmospheric ambient air in Ardabil, Iran

    NASA Astrophysics Data System (ADS)

    Hazrati, Sadegh; Rostami, Roohollah; Farjaminezhad, Manoochehr; Fazlzadeh, Mehdi

    2016-05-01

    BTEX concentrations in indoor and outdoor air of 50 homes were studied in Ardabil city and their influencing parameters including; heating system, using gas stove and samovar, tobacco smoking, the floors in which the monitored homes were located, and kitchen plan were considered in the study. Risk assessment analysis was carried out with the obtained concentrations based on EPA IRIS reference doses. BTEX compounds were sampled by charcoal tubes and the samples were analyzed by a GC-FID. Concentrations of benzene (15.18 μg/m3 vs. 8.65 μg/m3), toluene (69.70 μg/m3 vs. 40.56 μg/m3), ethylbenzene (12.07 μg/m3 vs. 4.92 μg/m3) and xylene (48.08 μg/m3 vs. 7.44 μg/m3) in indoor air were significantly (p < 0.05) higher than the levels quantified for outdoor air. The obtained concentrations of benzene were considerably higher than the recommended value of 5 μg/m3 established by Iran environmental protection organization. Among the BTEX compounds, benzene (HQ = 0.51) and xylene (HQ = 0.47) had notable hazard quotient and were the main pollutants responsible for high hazard index in the monitored homes (HI = 1.003). The results showed considerably high cancer risk for lifetime exposure to the indoor (125 × 10-6) and outdoor (71 × 10-6) benzene. Indoor benzene concentrations in homes were significantly influenced by type of heating system, story, and natural gas appliances.

  5. Stomatal uptake of O3 in aspen and aspen-birch forests under free-air CO2 and O3 enrichment.

    PubMed

    Uddling, Johan; Hogg, Alan J; Teclaw, Ronald M; Carroll, Mary Anne; Ellsworth, David S

    2010-06-01

    Rising atmospheric carbon dioxide (CO2) may alleviate the toxicological impacts of concurrently rising tropospheric ozone (O3) during the present century if higher CO2 is accompanied by lower stomatal conductance (gs), as assumed by many models. We investigated how elevated concentrations of CO2 and O3, alone and in combination, affected the accumulated stomatal flux of O3 (AFst) by canopies and sun leaves in closed aspen and aspen-birch forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin. Stomatal conductance for O3 was derived from sap flux data and AFst was estimated either neglecting or accounting for the potential influence of non-stomatal leaf surface O3 deposition. Leaf-level AFst (AFst(l)) was not reduced by elevated CO2. Instead, there was a significant CO2 x O(3) interaction on AFst(l), as a consequence of lower values of gs in control plots and the combination treatment than in the two single-gas treatments. In addition, aspen leaves had higher AFst(l) than birch leaves, and estimates of AFst(l) were not very sensitive to non-stomatal leaf surface O3 deposition. Our results suggest that model projections of large CO2-induced reductions in gs alleviating the adverse effect of rising tropospheric O3 may not be reasonable for northern hardwood forests.

  6. Where does the carbon go? A model-data intercomparison of vegetation carbon allocation and turnover processes at two temperate forest free-air CO2 enrichment sites.

    PubMed

    De Kauwe, Martin G; Medlyn, Belinda E; Zaehle, Sönke; Walker, Anthony P; Dietze, Michael C; Wang, Ying-Ping; Luo, Yiqi; Jain, Atul K; El-Masri, Bassil; Hickler, Thomas; Wårlind, David; Weng, Ensheng; Parton, William J; Thornton, Peter E; Wang, Shusen; Prentice, I Colin; Asao, Shinichi; Smith, Benjamin; McCarthy, Heather R; Iversen, Colleen M; Hanson, Paul J; Warren, Jeffrey M; Oren, Ram; Norby, Richard J

    2014-08-01

    Elevated atmospheric CO2 concentration (eCO2) has the potential to increase vegetation carbon storage if increased net primary production causes increased long-lived biomass. Model predictions of eCO2 effects on vegetation carbon storage depend on how allocation and turnover processes are represented. We used data from two temperate forest free-air CO2 enrichment (FACE) experiments to evaluate representations of allocation and turnover in 11 ecosystem models. Observed eCO2 effects on allocation were dynamic. Allocation schemes based on functional relationships among biomass fractions that vary with resource availability were best able to capture the general features of the observations. Allocation schemes based on constant fractions or resource limitations performed less well, with some models having unintended outcomes. Few models represent turnover processes mechanistically and there was wide variation in predictions of tissue lifespan. Consequently, models did not perform well at predicting eCO2 effects on vegetation carbon storage. Our recommendations to reduce uncertainty include: use of allocation schemes constrained by biomass fractions; careful testing of allocation schemes; and synthesis of allocation and turnover data in terms of model parameters. Data from intensively studied ecosystem manipulation experiments are invaluable for constraining models and we recommend that such experiments should attempt to fully quantify carbon, water and nutrient budgets.

  7. Stomatal uptake of O3 in aspen and aspen-birch forests under free-air CO2 and O3 enrichment.

    PubMed

    Uddling, Johan; Hogg, Alan J; Teclaw, Ronald M; Carroll, Mary Anne; Ellsworth, David S

    2010-06-01

    Rising atmospheric carbon dioxide (CO2) may alleviate the toxicological impacts of concurrently rising tropospheric ozone (O3) during the present century if higher CO2 is accompanied by lower stomatal conductance (gs), as assumed by many models. We investigated how elevated concentrations of CO2 and O3, alone and in combination, affected the accumulated stomatal flux of O3 (AFst) by canopies and sun leaves in closed aspen and aspen-birch forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin. Stomatal conductance for O3 was derived from sap flux data and AFst was estimated either neglecting or accounting for the potential influence of non-stomatal leaf surface O3 deposition. Leaf-level AFst (AFst(l)) was not reduced by elevated CO2. Instead, there was a significant CO2 x O(3) interaction on AFst(l), as a consequence of lower values of gs in control plots and the combination treatment than in the two single-gas treatments. In addition, aspen leaves had higher AFst(l) than birch leaves, and estimates of AFst(l) were not very sensitive to non-stomatal leaf surface O3 deposition. Our results suggest that model projections of large CO2-induced reductions in gs alleviating the adverse effect of rising tropospheric O3 may not be reasonable for northern hardwood forests. PMID:20089338

  8. Investigating the Multiple Food Sources and N Chemistry of Invasive Earthworms at the Rhinelander, WI, Free Air CO2 Enrichment (FACE) Experiment

    NASA Astrophysics Data System (ADS)

    Top, S. M.; Filley, T. R.

    2013-12-01

    Rising levels of atmospheric CO2 can directly and indirectly alter biogeochemical cycling in forest ecosystems through changes to plant productivity, tissue chemistry, and associated feedbacks to microbial and faunal communities. At the Rhinelander free air CO2 enrichment site (FACE), Rhinelander WI, we examined the consumption and movement of plant tissue and soil by invasive earthworm species using a multi-proxy stable isotope and amino acid chemistry analysis of plant and soil, as well as fecal matter extracted from invasive earthworms present at the site. Using an isotopic mixing model that exploits the 13C-depleted CO2 source and a previous 15N labeling in the FACE experiment, we determined potential sources to the earthworm fecal matter and the movement of amino compounds. For epigeic, surface dwelling earthworms, the stable isotope modeling showed the largest contribution to the C and N in fecal matter was from leaf litter (up to 80%) which was depleted in amino acid C under elevated CO2 conditions. Fecal matter from the endogeic, mineral soil dwelling earthworms was primarily derived from 0-5 cm soil (up to 56%) and fine root tissue (up to 70%). Additionally, amino acid C in this group of earthworms had a proportionately greater relative concentration compared to the epigeic species and the 0-5cm soil. Here we demonstrate that earthworms are incorporating multiple sources (leaf litter, root, and soil) into their fecal matter, which then get deposited throughout the soil profile, where nutrients could become available for plant use.

  9. [Estimation of average traffic emission factor based on synchronized incremental traffic flow and air pollutant concentration].

    PubMed

    Li, Run-Kui; Zhao, Tong; Li, Zhi-Peng; Ding, Wen-Jun; Cui, Xiao-Yong; Xu, Qun; Song, Xian-Feng

    2014-04-01

    On-road vehicle emissions have become the main source of urban air pollution and attracted broad attentions. Vehicle emission factor is a basic parameter to reflect the status of vehicle emissions, but the measured emission factor is difficult to obtain, and the simulated emission factor is not localized in China. Based on the synchronized increments of traffic flow and concentration of air pollutants in the morning rush hour period, while meteorological condition and background air pollution concentration retain relatively stable, the relationship between the increase of traffic and the increase of air pollution concentration close to a road is established. Infinite line source Gaussian dispersion model was transformed for the inversion of average vehicle emission factors. A case study was conducted on a main road in Beijing. Traffic flow, meteorological data and carbon monoxide (CO) concentration were collected to estimate average vehicle emission factors of CO. The results were compared with simulated emission factors of COPERT4 model. Results showed that the average emission factors estimated by the proposed approach and COPERT4 in August were 2.0 g x km(-1) and 1.2 g x km(-1), respectively, and in December were 5.5 g x km(-1) and 5.2 g x km(-1), respectively. The emission factors from the proposed approach and COPERT4 showed close values and similar seasonal trends. The proposed method for average emission factor estimation eliminates the disturbance of background concentrations and potentially provides real-time access to vehicle fleet emission factors.

  10. Laser induced fluorescence measurements of dissolved oxygen concentration fields near air bubble surfaces

    NASA Astrophysics Data System (ADS)

    Roy, Sabita; Duke, Steve R.

    2000-09-01

    This article describes a laser-induced fluorescence (LIF) technique for measuring dissolved oxygen concentration gradients in water near the surface of an air bubble. Air bubbles are created at the tip of a needle in a rectangular bubble column filled with water that contains pyrenebutyric acid (PBA). The fluorescence of the PBA is induced by a planar pulse of nitrogen laser light. Oxygen transferring from the air bubble to the deoxygenated water quenches the fluorescence of the PBA. Images of the instantaneous and two-dimensional fluorescence field are obtained by a UV-intensified charge-coupled device (CCD) camera. Quenching of fluorescence intensity is determined at each pixel in the CCD image to measure dissolved oxygen concentration. Two-dimensional concentration fields are presented for a series of measurements of oxygen transfer from 1.6 mm bubbles suspended on the tip of a needle in a quiescent fluid. The images show the spatially varying concentration profiles, gradients, and boundary layer thicknesses at positions around the bubble surfaces. These direct and local measurements of concentration behavior within the mass transfer boundary layer show the potential of this LIF technique for the development of general and mechanistic models for oxygen transport across the air-water interface.

  11. [Concentrations and influencing factors of gaseous polycyclic aromatic hydrocarbons in residential air in Beijing].

    PubMed

    Wei, Zhi-cheng; Chang, Biao; Qiu, Wei-xun; Wang, Yi; Wu, Shi-min; Xing, Bao-shan; Liu, Wen-xin; Tao, Shu

    2007-09-01

    7 gas phase PAHs components in indoor air collected from 38 families were investigated by modified passive air samplers in Beijing areas during the local heating and non-heating seasons, and the influencing factors were discussed as well. The analytical results indicate that the gasous PAHs in local indoor air are dominated by 2 and 3 rings compounds, the mean concentrations for the 7 individual gaseous components range from 1 to 40 ng/m3, and the average concentration of total gaseous PAHs is about 100 ng/m3. There is no significant difference in total gaseous PAHs concentrations between the heating and the non-heating seasons, while some apparent seasonal changes occur in ACY and FLA concentrations. Compared with heating season, contribution of 2 rings compounds decreases while the proportions of 3 and 4 rings species increase during the non-heating season. Based on household activity questionnaires and actual analytical concentrations, the main influencing factors accounted for gaseous PAHs in indoor air, identified by multifactor analysis of variance, include cigarette smoking, use of moth ball, intensity of draft, cuisine frequency and built age.

  12. Comparison of mold concentrations quantified by MSQPCR in indoor and outdoor air sampled simultaneously

    SciTech Connect

    Meklin, Teija; Reponen, Tina; McKinstry, Craig A.; Cho, Seung H.; Grinshpun, Sergey A.; Nevalainen, Aino; Vepsalainen, Asko; Haugland, Richard A.; Lemasters, Grace; Vesper, Sephen J.

    2007-08-15

    Mold specific quantitative PCR (MSQPCR) was used to measure the concentrations of 36 mold species in dust and in indoor and in outdoor air samples that were taken simultaneously in 17 homes in Cincinnati with no-known water damage. The total spore concentrations in the indoor (I) and outdoor (O) air samples were statistically significantly different and the concentrations in the three sample types of many of the individual species were significantly different (p < 0.05 based on the Wilcoxon Signed Rank Test). The I/O ratios of the averages or geometric means of the individual species were generally less than 1; but these I/O ratios were quite variable ranging from 0.03 for A. sydowii to 1.2 for Acremonium strictum. There were no significant correlations for the 36 specific mold concentrations between the dust samples and the indoor or outdoor air samples (based on the Spearman’s Rho test). The indoor and outdoor air concentrations of 32 of the species were not correlated. Only Aspergillus penicillioides, C. cladosporioides types 1 and 2 and C. herbarum had sufficient data to estimate a correlation at rho > 0.5 with signicance (p < 0.05) In six of these homes, a previous dust sample had been collected and analyzed 2 years earlier. The ERMI© values for the dust samples taken in the same home two years apart were not significantly different (p=0.22) based on Wilcoxon Signed Rank Test.

  13. Productivity and selenium concentrations in egg and tissue of laying quails fed selenium from hydroponically produced selenium-enriched kale sprout (Brassica oleracea var. alboglabra L.).

    PubMed

    Chinrasri, Orawan; Chantiratikul, Piyanete; Maneetong, Sarunya; Chookhampaeng, Sumalee; Chantiratikul, Anut

    2013-12-01

    This study aimed to determine the effectiveness of Se from hydroponically produced Se-enriched kale sprout (HPSeKS) on productive performance, egg quality, and Se concentrations in egg and tissue of laying quails. Two-hundred quails, 63 days of age, were divided into four groups. Each group consisted of five replicates and each replicate had ten birds, according to a completely randomized design. The experiment lasted for 6 weeks. The dietary treatments were T1 (control diet), T2 (control diet plus 0.2 mg Se/kg from sodium selenite), T3 (control diet plus 0.2 mg Se/kg from Se-enriched yeast), T4 (control diet plus 0.2 mg Se/kg from HPSeKS). The findings revealed that productive performance and egg quality of quails were not altered (p > 0.05) by Se sources. Whole egg Se concentrations of quails fed Se from HPSeKS and Se-enriched yeast were higher (p < 0.05) than that of quails fed the control diet. Breast muscle Se concentrations in quails fed Se from HPSeKS were higher (p < 0.05) than that of quails fed Se from sodium selenite and Se-enriched yeast. Heart tissue Se concentrations of quails fed Se from Se-enriched yeast and HPSeKS were similar (p > 0.05), but higher (p < 0.05) than that of quails fed Se from sodium selenite. The results reveal that Se from HPSeKS did not change the performance and egg quality of quails. The effectiveness of Se from HPSeKS was comparable to that of Se-enriched yeast, which was higher than that of Se from sodium selenite.

  14. Preparation of C60-functionalized magnetic silica microspheres for the enrichment of low-concentration peptides and proteins for MALDI-TOF MS analysis.

    PubMed

    Chen, Hemei; Qi, Dawei; Deng, Chunhui; Yang, Penyuan; Zhang, Xiangmin

    2009-01-01

    In this work, for the first time, a novel C60-functionalized magnetic silica microsphere (designated C60-f-MS) was synthesized by radical polymerization of C60 molecules on the surface of magnetic silica microspheres. The resulting C60-f-MS microsphere has magnetite core and thin C60 modified silica shell, which endow them with useful magnetic responsivity and surface affinity toward low-concentration peptides and proteins. As a result of their excellent magnetic property, the synthesized C60-f-MS microspheres can be easily separated from sample solution without ultracentrifuge. The C60-f-MS microspheres were successfully applied to the enrichment of low-concentration peptides in tryptic protein digest and human urine via a MALDI-TOF MS analysis. Moreover, they were demonstrated to have enrichment efficiency for low-concentration proteins. Due to the novel materials maintaining excellent magnetic properties and admirable adsorption, the process of enrichment and desalting is very fast (only 5 min), convenient and efficient. As it has been demonstrated in the study, newly developed fullerene-derivatized magnetic silica materials are superior to those already available in the market. The facile and low-cost synthesis as well as the convenient and efficient enrichment process of the novel C60-f-MS microspheres makes it a promising candidate for isolation of low-concentration peptides and proteins even in complex biological samples such as serum, plasma, and urine or cell lysate. PMID:19086100

  15. Monitor of the concentration of particles of dense radioactive materials in a stream of air

    DOEpatents

    Yule, Thomas J.

    1979-01-01

    A monitor of the concentration of particles of radioactive materials such as plutonium oxide in diameters as small as 1/2 micron includes in combination a first stage comprising a plurality of virtual impactors, a second stage comprising a further plurality of virtual impactors, a collector for concentrating particulate material, a radiation detector disposed near the collector to respond to radiation from collected material and means for moving a stream of air, possibly containing particulate contaminants, through the apparatus.

  16. Application of hybrid coagulation microfiltration with air backflushing to direct sewage concentration for organic matter recovery.

    PubMed

    Jin, Zhengyu; Gong, Hui; Wang, Kaijun

    2015-01-01

    The idea of sewage concentration is gradually being accepted as a promising and sustainable way of wastewater resource recovery. In this study, Hybrid coagulation microfiltration (HCM) with air backflushing (AB) was investigated to effectively concentrate organic matter. Compared to direct sewage microfiltration, the addition of coagulation process improved the filtration performance with less fouling trends and better concentration efficiency. The use of AB exhibited even better performance within the same 7-h preliminary concentration period by reducing to one tenth of the resistance and collecting around four times as much organic matter into the product concentrate as in direct sewage microfiltration. During 93-h lab-scale continuous concentration by HCM with AB, a product concentrate with the COD concentration over 15,000 mg/L was achieved and around 70% of total influent organic matter could be recovered. Compared to Direct Membrane Filtration (DMF) with Chemically Enhanced Backwash (CEB), HCM with AB achieved better concentration efficiency with higher concentration extent and concentration velocity along with less organic matter mineralization and the more concentrated product despite with lower organic matter retention. HCM with AB could be a promising effective sewage organic matter concentration for resource recovery under optimization.

  17. A Comparison of Statistical Techniques for Combining Modeled and Observed Concentrations to Create High-Resolution Ozone Air Quality Surfaces

    EPA Science Inventory

    Air quality surfaces representing pollutant concentrations across space and time are needed for many applications, including tracking trends and relating air quality to human and ecosystem health. The spatial and temporal characteristics of these surfaces may reveal new informat...

  18. Effect of geocoding errors on traffic-related air pollutant exposure and concentration estimates

    EPA Science Inventory

    Exposure to traffic-related air pollutants is highest very near roads, and thus exposure estimates are sensitive to positional errors. This study evaluates positional and PM2.5 concentration errors that result from the use of automated geocoding methods and from linearized approx...

  19. Performance of the Proposed New Federal Reference Methods for Measuring Ozone Concentrations in Ambient Air

    EPA Science Inventory

    The current Federal Reference Method (FRM) for measuring concentrations of ozone in ambient air, described in EPA regulations at 40 CFR Part 50, Appendix D, is based on the dry, gas-phase, chemiluminescence reaction between ethylene (C2H4) and any ozone (O

  20. Modeling and Impacts of Traffic Emissions on Air Toxics Concentrations near Roadways

    EPA Science Inventory

    The dispersion formulation incorporated in the U.S. Environmental Protection Agency’s AERMOD regulatory dispersion model is used to estimate the contribution of traffic-generated emissions of select VOCs – benzene, 1,3-butadiene, toluene – to ambient air concentrations at downwin...

  1. Evaluation and Comparison of Chemiluminescence and UV Photometric Methods for Measuring Ozone Concentrations in Ambient Air

    EPA Science Inventory

    The current Federal Reference Method (FRM) for measuring concentrations of ozone in ambient air is based on the dry, gas-phase, chemiluminescence reaction between ethylene (C2H4) and any ozone (O3) that may be p...

  2. Ozone concentrations and damage for realistic future European climate and air quality scenarios

    NASA Astrophysics Data System (ADS)

    Hendriks, Carlijn; Forsell, Nicklas; Kiesewetter, Gregor; Schaap, Martijn; Schöpp, Wolfgang

    2016-11-01

    Ground level ozone poses a significant threat to human health from air pollution in the European Union. While anthropogenic emissions of precursor substances (NOx, NMVOC, CH4) are regulated by EU air quality legislation and will decrease further in the future, the emissions of biogenic NMVOC (mainly isoprene) may increase significantly in the coming decades if short-rotation coppice plantations are expanded strongly to meet the increased biofuel demand resulting from the EU decarbonisation targets. This study investigates the competing effects of anticipated trends in land use change, anthropogenic ozone precursor emissions and climate change on European ground level ozone concentrations and related health and environmental impacts until 2050. The work is based on a consistent set of energy consumption scenarios that underlie current EU climate and air quality policy proposals: a current legislation case, and an ambitious decarbonisation case. The Greenhouse Gas-Air Pollution Interactions and Synergies (GAINS) integrated assessment model was used to calculate air pollutant emissions for these scenarios, while land use change because of bioenergy demand was calculated by the Global Biosphere Model (GLOBIOM). These datasets were fed into the chemistry transport model LOTOS-EUROS to calculate the impact on ground level ozone concentrations. Health damage because of high ground level ozone concentrations is projected to decline significantly towards 2030 and 2050 under current climate conditions for both energy scenarios. Damage to plants is also expected to decrease but to a smaller extent. The projected change in anthropogenic ozone precursor emissions is found to have a larger impact on ozone damage than land use change. The increasing effect of a warming climate (+2-5 °C across Europe in summer) on ozone concentrations and associated health damage, however, might be higher than the reduction achieved by cutting back European ozone precursor emissions. Global

  3. The photosynthetic acclimation of Lolium perenne in response to three years growth in a free-air CO{sub 2} enrichment (FACE) system

    SciTech Connect

    Hymus, G.J. |

    1996-08-01

    Pure stands of Ryegrass were in their third year of growth in the field, exposed to either ambient (355 {mu}mol mol{sup -1}), or elevated (600 {mu}mol mol{sup -1}) atmospheric CO{sub 2} concentration. A Free-Air CO{sub 2} Enrichment (FACE) system was used to maintain the elevated CO{sub 2} concentration whilst limiting experimental constraints on the field conditions. The theoretically predicted increase in the net rates of CO{sub 2} uptake per unit leaf area (A {mu}mol mol{sup -1}) as a consequence, primarily, of the suppression of photorespiration by CO{sub 2} a competitive inhibitor of RubP oxygenation by Rubisco, was observed for the Lolium perenne studied. Also observed was a general decline in leaf evapotranspiration (E) consistent with observations of increased water use efficiency of crops grown in elevated CO{sub 2}. Enhancement of leaf A in the FACE grown L. perenne ranged from 26.5 1 % to 44.95% over the course of a diurnal set of measurements. Whilst reductions in leaf E reached a maximum of 16.61% over the same diurnal course of-measurements. The increase in A was reconciled with an absence of the commonly observed decline in V{sub c}{sub max} as a measure of the maximum in vivo carboxylation capacity of the primary carboxylasing enzyme Rubisco and J{sub max} a measure of the maximum rate of electron transport. The manipulation of the source sink balance of the crop, stage of canopy regrowth or height in the canopy had no effect on the observation of a lack of response. The findings of this study will be interpreted with respect to the long term implications of C{sub 3} crops being able to adapt physiologically to maximize the potential benefits conferred by growth in elevated CO{sub 2}.

  4. Autism spectrum disorder prevalence and associations with air concentrations of lead, mercury, and arsenic.

    PubMed

    Dickerson, Aisha S; Rahbar, Mohammad H; Bakian, Amanda V; Bilder, Deborah A; Harrington, Rebecca A; Pettygrove, Sydney; Kirby, Russell S; Durkin, Maureen S; Han, Inkyu; Moyé, Lemuel A; Pearson, Deborah A; Wingate, Martha Slay; Zahorodny, Walter M

    2016-07-01

    Lead, mercury, and arsenic are neurotoxicants with known effects on neurodevelopment. Autism spectrum disorder (ASD) is a neurodevelopmental disorder apparent by early childhood. Using data on 4486 children with ASD residing in 2489 census tracts in five sites of the Centers for Disease Control and Prevention's Autism and Developmental Disabilities Monitoring (ADDM) Network, we used multi-level negative binomial models to investigate if ambient lead, mercury, and arsenic concentrations, as measured by the US Environmental Protection Agency National-Scale Air Toxics Assessment (EPA-NATA), were associated with ASD prevalence. In unadjusted analyses, ambient metal concentrations were negatively associated with ASD prevalence. After adjusting for confounding factors, tracts with air concentrations of lead in the highest quartile had significantly higher ASD prevalence than tracts with lead concentrations in the lowest quartile (prevalence ratio (PR) = 1.36; 95 '% CI: 1.18, 1.57). In addition, tracts with mercury concentrations above the 75th percentile (>1.7 ng/m(3)) and arsenic concentrations below the 75th percentile (≤0.13 ng/m(3)) had a significantly higher ASD prevalence (adjusted RR = 1.20; 95 % CI: 1.03, 1.40) compared to tracts with arsenic, lead, and mercury concentrations below the 75th percentile. Our results suggest a possible association between ambient lead concentrations and ASD prevalence and demonstrate that exposure to multiple metals may have synergistic effects on ASD prevalence.

  5. Total internal reflection-based planar waveguide solar concentrator with symmetric air prisms as couplers.

    PubMed

    Xie, Peng; Lin, Huichuan; Liu, Yong; Li, Baojun

    2014-10-20

    We present a waveguide coupling approach for planar waveguide solar concentrator. In this approach, total internal reflection (TIR)-based symmetric air prisms are used as couplers to increase the coupler reflectivity and to maximize the optical efficiency. The proposed concentrator consists of a line focusing cylindrical lens array over a planar waveguide. The TIR-based couplers are located at the focal line of each lens to couple the focused sunlight into the waveguide. The optical system was modeled and simulated with a commercial ray tracing software (Zemax). Results show that the system used with optimized TIR-based couplers can achieve 70% optical efficiency at 50 × geometrical concentration ratio, resulting in a flux concentration ratio of 35 without additional secondary concentrator. An acceptance angle of ± 7.5° is achieved in the x-z plane due to the use of cylindrical lens array as the primary concentrator.

  6. Photosynthesis and growth responses of mustard (Brassica juncea L. cv Pusa Bold) plants to free air carbon dioxide enrichment (FACE).

    PubMed

    Ruhil, Kamal; Sheeba; Ahmad, Altaf; Iqbal, Muhammad; Tripathy, Baishnab C

    2015-07-01

    Increased atmospheric [CO2] is likely to affect photosynthesis, plant growth, and yield potential of plants. Mustard (Brassica juncea L.) is an important oil seed crop that is widely grown in India. Therefore, the impact of elevated [CO2] (585 μmol mol(-1)) on pigment and protein content, chlorophyll a fluorescence, photosynthetic electron transport reactions, CO2 assimilation, biomass production, and seed yield potential was measured in B. juncea cv Pusa Bold, grown inside free air carbon dioxide enrichment (FACE) rings installed on the campus of Jawaharlal Nehru University, New Delhi, India. Plants were grown for three consecutive winter seasons (2010-2013), in ambient (385 μmol mol(-1)) or elevated [CO2], in field conditions. Elevated [CO2] had no significant effect on the minimal chlorophyll fluorescence (F 0), while the quantum efficiency of Photosystem II, measured as variable fluorescence (F v = F m-F 0) to maximum fluoresence (F m), increased by 3 %. Electron transport rate, photosystem I, photosystem II, and whole chain electron transport rates increased by 8 % in elevated [CO2]. However, the net photosynthesis rate increased by ≈50 % in three growing seasons under elevated [CO2] condition. The stomatal conductance and transpiration rate decreased resulting in higher photosynthetic water use efficiency. The photosynthesizing surface, i.e., leaf area index substantially increased leading to higher biomass and seed yield under elevated [CO2] condition. Acclimatory downregulation of photosynthesis and plant productivity was not observed in three consecutive growing years suggesting that in the absence of nutrient limitation, B. juncea is highly responsive to elevated CO2 whose yield potential shall increase in changing climatic conditions. PMID:25471475

  7. Photosynthesis and growth responses of mustard (Brassica juncea L. cv Pusa Bold) plants to free air carbon dioxide enrichment (FACE).

    PubMed

    Ruhil, Kamal; Sheeba; Ahmad, Altaf; Iqbal, Muhammad; Tripathy, Baishnab C

    2015-07-01

    Increased atmospheric [CO2] is likely to affect photosynthesis, plant growth, and yield potential of plants. Mustard (Brassica juncea L.) is an important oil seed crop that is widely grown in India. Therefore, the impact of elevated [CO2] (585 μmol mol(-1)) on pigment and protein content, chlorophyll a fluorescence, photosynthetic electron transport reactions, CO2 assimilation, biomass production, and seed yield potential was measured in B. juncea cv Pusa Bold, grown inside free air carbon dioxide enrichment (FACE) rings installed on the campus of Jawaharlal Nehru University, New Delhi, India. Plants were grown for three consecutive winter seasons (2010-2013), in ambient (385 μmol mol(-1)) or elevated [CO2], in field conditions. Elevated [CO2] had no significant effect on the minimal chlorophyll fluorescence (F 0), while the quantum efficiency of Photosystem II, measured as variable fluorescence (F v = F m-F 0) to maximum fluoresence (F m), increased by 3 %. Electron transport rate, photosystem I, photosystem II, and whole chain electron transport rates increased by 8 % in elevated [CO2]. However, the net photosynthesis rate increased by ≈50 % in three growing seasons under elevated [CO2] condition. The stomatal conductance and transpiration rate decreased resulting in higher photosynthetic water use efficiency. The photosynthesizing surface, i.e., leaf area index substantially increased leading to higher biomass and seed yield under elevated [CO2] condition. Acclimatory downregulation of photosynthesis and plant productivity was not observed in three consecutive growing years suggesting that in the absence of nutrient limitation, B. juncea is highly responsive to elevated CO2 whose yield potential shall increase in changing climatic conditions.

  8. Deposition and air concentrations of permethrin and naled used for adult mosquito management.

    PubMed

    Schleier, Jerome J; Peterson, Robert K D

    2010-01-01

    One of the most effective ways of managing adult mosquitoes that vector human and animal pathogens is the use of ultra-low-volume (ULV) insecticides. Because of the lack of environmental fate studies and concerns about the safety of the insecticides used for the management of adult mosquitoes, we conducted an environmental fate study after truck-mounted applications of permethrin and naled. One hour after application, concentrations of permethrin on cotton dosimeters placed at ground level 25, 50, and 75 m from the spray source were 2, 4, and 1 ng/cm2 in 2007 and 5, 2, and 0.9 ng/cm2 in 2008, respectively. One hour after application, concentrations of naled 25, 50, and 75 m were 47, 66, and 67 ng/cm2 in 2007 and 15, 6.1, and 0 (nondetectable) ng/cm2 in 2008, respectively. Deposition concentrations 12 h after application were not significantly different than 1 h after application for permethrin and naled either year. During 2007 and 2008 permethrin applications, two quantifiable air concentrations of 375 and 397 ng/m3 were observed 1 h after application. In 2007 and 2008, naled air concentrations ranged from 2300 to 4000 ng/m3 1 h after application. There were no quantifiable air concentrations between 1 and 12 h after application in either 2007 or 2008 for both naled and permethrin. Environmental concentrations observed in this study demonstrate that models used in previous risk assessments were sufficiently conservative (i.e., the models overestimated environmental concentrations). However, we also demonstrate inadequacies of models such as AgDrift and AGDISP, which currently are used by the US Environmental Protection Agency to estimate environmental concentrations of ULV insecticides. PMID:19536586

  9. Soil air carbon dioxide and nitrous oxide concentrations in profiles under tallgrass prairie and cultivation

    SciTech Connect

    Sotomayor, D.; Rice, C.W.

    1999-05-01

    Assessing the dynamics of gaseous production in soils is of interest because they are important sources and sinks of greenhouse gases. Changes in soil air carbon dioxide (CO{sub 2}) and nitrous oxide (N{sub 2}O) concentrations were studied in a Reading silt loam under prairie and cultivation. Concentrations were measured in situ over a 17-mo period to a depth of 3 m. Multilevel samples permitted collection of gases with subsequent measurement by gas chromatography in the laboratory. Soil air N{sub 2}O concentrations were near atmospheric levels for a majority of the study period in the prairie site but were significantly higher in the cultivated site. Annual mean N{sub 2}O concentrations were 0.403 and 1.09 {micro}L L{sup {minus}1} in the prairie and cultivated sites, respectively. Soil air CO{sub 2} annual mean concentrations were 1.56 {times} 10{sup 4} and 1.10 {times} 10{sup 4} {micro}L L{sup {minus}1} and ranged from 0.096 {times} 10{sup 4} to 6.45 {times} 10{sup 4} {micro}L L{sup {minus}1} and 0.087 {times} 10{sup 4} to 3.59 {times} 10{sup 4} {micro}L L{sup {minus}1} in the prairie and cultivated sites, respectively. Concentrations generally increased with depth, with maximum soil air N{sub 2}O and CO{sub 2} concentrations at 1.0 m in the prairie site and 0.5 m in the cultivated site. Nitrous oxide in the cultivated site and CO{sub 2} at both sites did not change markedly over winter months, but CO{sub 2} and N{sub 2}O concentrations reached maximums during the summer months and decreased as the year progressed. Although soil air concentrations peaked and decreased faster at shallower depths, deeper depths exhibited relative maximum concentrations for longer time periods.

  10. Ozone concentration in leaf intercellular air spaces is close to zero

    SciTech Connect

    Laisk, A.; Moldau, H. ); Kull, O. )

    1989-07-01

    Transpiration and ozone uptake rates were measured simultaneously in sunflower leaves at different stomatal openings and various ozone concentrations. Ozone uptake rates were proportional to the ozone concentration up to 1500 nanoliters per liter. The leaf gas phase diffusion resistance (stomatal plus boundary layer) to water vapor was calculated and converted to the resistance to ozone multiplying it by the theoretical ratio of diffusion coefficients for water vapor and ozone in air (1.67). The ozone concentration in intercellular air spaces calculated from the ozone uptake rate and diffusion resistance to ozone scattered around zero. The ozone concentration in intercellular air spaces was measured directly bu supplying ozone to the leaf from one side and measuring the equilibrium concentration above the other side, and it was found to be zero. The total leaf resistance to ozone was proportional to the gas phase resistance to water vapor with a coefficient of 1.68. It is concluded that ozone enters the leaf by diffusion through the stomata, and is rapidly decomposed in cell walls and plasmalemma.

  11. Ozone concentration in leaf intercellular air spaces is close to zero.

    PubMed

    Laisk, A; Kull, O; Moldau, H

    1989-07-01

    Transpiration and ozone uptake rates were measured simultaneously in sunflower leaves at different stomatal openings and various ozone concentrations. Ozone uptake rates were proportional to the ozone concentration up to 1500 nanoliters per liter. The leaf gas phase diffusion resistance (stomatal plus boundary layer) to water vapor was calculated and converted to the resistance to ozone multiplying it by the theoretical ratio of diffusion coefficients for water vapor and ozone in air (1.67). The ozone concentration in intercellular air spaces calculated from the ozone uptake rate and diffusion resistance to ozone scattered around zero. The ozone concentration in intercellular air spaces was measured directly by supplying ozone to the leaf from one side and measuring the equilibrium concentration above the other side, and it was found to be zero. The total leaf resistance to ozone was proportional to the gas phase resistance to water vapor with a coefficient of 1.68. It is concluded that ozone enters the leaf by diffusion through the stomata, and is rapidly decomposed in cell walls and plasmalemma.

  12. Study of a cave's air exchange pattern based on radon concentration and the time dependence of radon concentration in Pál-völgy Cave (Budapest, Hungary)

    NASA Astrophysics Data System (ADS)

    Nagy, H. E.; Horvath, A.; Jordan, Gy.; Szabo, Cs.; Kiss, A.

    2012-04-01

    A long-term (one year and a half), high resolution, with an integration time of one hour, radon concentration monitoring was carried out in Pál-völgy Cave (Budapest, Hungary). Our major goal was to determine the time dependence of radon concentration in the cave and to understand the exchange pattern of the cave air with the outdoor air based on radon concentrations, and to determine the factors that affect the radon concentration in the cave air. Pál-völgy Cave is situated in the Buda Hills, which is the NE part of the Transdanubian Central Range. The wall rock of the cave is dominantly Eocene Szépvölgy Limestone Formation. Above the limestone Eocene Buda Marl and Oligocene Tard Clay are deposited. A huge multiphase hydrothermal cave system developed in the Szépvölgy Limestone and partially in the Buda Marl resulted in a long-term complex paleokarstic evolution from the Late Eocene to the Quaternary. The radon concentration in the cave air was measured continuously by an AlphaGuard radon monitor, and meteorological parameters outside the cave were also collected simultaneously. The arithmetic mean of the annual radon concentration was 1.9 kBq/m3 and the radon concentration varied between 104-7,776 Bq/m3. In addition, the results indicate a clear seasonal variability of radon concentration in the cave air: in winter the radon concentration fluctuates around a low mean value of 253 Bq/m3, in summer it oscillates around a high mean value of 5,504 Bq/m3, whereas in spring and autumn the radon level varies between the winter and summer values. The summer to winter radon concentration ratio (radon concentration in summer/radon concentration in winter) was high, 21.8. The outside air temperature showed the strongest correlation with the radon concentration in the cave, Pierson's linear correlation coefficient is 0.76. If the outdoor air temperature is lower than the cave air temperature (12 °C), especially in autumn and winter the air flows from outside into the

  13. Chlorinated paraffins in indoor air and dust: concentrations, congener patterns, and human exposure.

    PubMed

    Fridén, Ulrika E; McLachlan, Michael S; Berger, Urs

    2011-10-01

    Chlorinated paraffins (CPs) are large production volume chemicals used in a wide variety of commercial applications. They are ubiquitous in the environment and humans. Human exposure via the indoor environment has, however, been barely investigated. In the present study 44 indoor air and six dust samples from apartments in Stockholm, Sweden, were analyzed for CPs, and indoor air concentrations are reported for the first time. The sumCP concentration (short chain CPs (SCCPs) and medium chain CPs (MCCPs)) in air ranged from <5-210 ng m(-3) as quantified by gas chromatography coupled to electron ionization tandem mass spectrometry (GC/EI-MS/MS). Congener group patterns were studied using GC with electron capture negative ionization MS (GC/ECNI-MS). The air samples were dominated by the more volatile SCCPs compared to MCCPs. SumCPs were quantified by GC/EI-MS/MS in the dust samples at low μg g(-1) levels, with a chromatographic pattern suggesting the prevalence of longer chain CPs compared to air. The median exposure to sumCPs via the indoor environment was estimated to be ~1 μg day(-1) for both adults and toddlers. Adult exposure was dominated by inhalation, while dust ingestion was suggested to be more important for toddlers. Comparing these results to literature data on dietary intake indicates that human exposure to CPs from the indoor environment is not negligible. PMID:21612825

  14. Fungal spore concentrations in two haematopoietic stem cell transplantation (HSCT) units containing distinct air control systems.

    PubMed

    Brun, C P; Miron, D; Silla, L M R; Pasqualotto, A C

    2013-04-01

    Invasive fungal diseases have emerged as important causes of morbidity and mortality in haematological patients. In this study air samples were collected in two haematopoietic stem cell transplantation (HSCT) units, in which distinct air-control systems were in place. In hospital 1 no high-efficiency particulate air (HEPA) filter was available whereas in hospital 2 HSCT rooms were equipped with HEPA filters, with positive air pressure in relation to the corridor. A total of 117 samples from rooms, toilets and corridors were obtained during December 2009 to January 2011, using a six-stage Andersen sampler. In both hospitals, the concentration of potentially pathogenic fungi in the air was reduced in patients' rooms compared to corridors (P < 0·0001). Despite the presence of a HEPA filter in hospital 2, rooms in both hospitals showed similar concentrations of potentially pathogenic fungi (P = 0·714). These findings may be explained by the implementation of additional protective measures in hospital 1, emphasizing the importance of such measures in protected environments. PMID:22691688

  15. Investigation of air pollution concentration in Kathmandu valley during winter season.

    PubMed

    Kondo, Akir; Kaga, Akikazu; Imamura, Kiyoshi; Inoue, Yoshio; Sugisawa, Masahiko; Shrestha, Manohar Lal; Sapkota, Balkrishan

    2005-01-01

    The monthly concentrations of NO2, NOx, SO2 and O3 measured by a passive sampler from February 2003 to January 2004 showed that the air pollution during the winter season in Kathmandu valley was higher than the summer season. The O3 level was found the highest during April, May and June due to strong radiation. The hourly concentrations of NO2, NOx, O3 and suspended particulate matter (SPM) were also measured by automatic instruments on December 2003. Temperature at the height of 60 m and 400 m at Raniban Mountain in the northwest of Kathmandu valley was measured on February 2001 in the winter season and the average potential temperature gradient was estimated from observed temperature. Wind speed was also measured at the department of hydrology, airport section, from 18 February to 6 March 2001. It was found that the stable layer and the calm condition in the atmosphere strongly affected the appearance of the maximum concentrations of NO2 and SPM in the morning, and that the unstable layer and the windy condition in the atmosphere was considerably relevant to the decrease of air pollution concentrations at daytime. The emission amounts of NOx, HCs and total suspended particle(TSP) from transport sector in 2003 were estimated from the increasing rate of vehicles on the basis of the emission amounts in 1993 to be 3751 t/a, 30570 t/a and 1317 t/a, respectively. The diurnal concentrations in 2003 calculated by the two-layers box model reproduced the characteristics of air pollution in Kathmandu valley such as the maximum value of O3 and its time, the maximum value of NO in the morning, and the decrease of NO and NO2 at daytime. The comparison with the concentrations in 1993 calculated suggested that the main cause of air pollution was the emission from transport sector.

  16. Multistage open-tube trap for enrichment of part-per-trillion trace components of low-pressure (below 27-kPa) air samples

    NASA Technical Reports Server (NTRS)

    Ohara, D.; Vo, T.; Vedder, J. F.

    1985-01-01

    A multistage open-tube trap for cryogenic collection of trace components in low-pressure air samples is described. The open-tube design allows higher volumetric flow rates than densely packed glass-bead traps commonly reported and is suitable for air samples at pressures below 27 kPa with liquid nitrogen as the cryogen. Gas blends containing 200 to 2500 parts per trillion by volume each of ethane and ethene were sampled and hydrocarbons were enriched with 100 + or - 4 percent trap efficiency. The multistage design is more efficient than equal-length open-tube traps under the conditions of the measurements.

  17. Air toxics concentrations, source identification, and health risks: An air pollution hot spot in southwest Memphis, TN

    NASA Astrophysics Data System (ADS)

    Jia, Chunrong; Foran, Jeffery

    2013-12-01

    Southwest Memphis is a residential region surrounded by fossil fuel burning, steel, refining, and food processing industries, and considerable mobile sources whose emissions may pose adverse health risks to local residents. This study characterizes cancer and non-cancer risks resulting from exposure to ambient air toxics in southwest Memphis. Air toxics samples were collected at a central location every 6 days from June 5, 2008 to January 8, 2010. Volatile organic compounds (VOCs) were collected in evacuated stainless-steel canisters and aldehydes by DNPH cartridges, and samples were analyzed for 73 target compounds. A total of 60 compounds were detected and 39 were found in over 86% of the samples. Mean concentrations of many compounds were higher than those measured in many industrial communities throughout the U.S. The cumulative cancer risk associated with exposure to 13 carcinogens found in southwest Memphis air was 2.3 × 10-4, four times higher than the national average of 5.0 × 10-5. Three risk drivers were identified: benzene, formaldehyde, and acrylonitrile, which contributed 43%, 19%, and 14% to the cumulative risk, respectively. This is the first field study to confirm acrylonitrile as a potential risk driver. Mobile, secondary, industrial, and background sources contributed 57%, 24%, 14%, and 5% of the risk, respectively. The results of this study indicate that southwest Memphis, a region of significant income, racial, and social disparities, is also a region under significant environmental stress compared with surrounding areas and communities.

  18. Air concentrations of PBDEs on in-flight airplanes and assessment of flight crew inhalation exposure.

    PubMed

    Allen, Joseph G; Sumner, Ann Louise; Nishioka, Marcia G; Vallarino, Jose; Turner, Douglas J; Saltman, Hannah K; Spengler, John D

    2013-07-01

    To address the knowledge gaps regarding inhalation exposure of flight crew to polybrominated diphenyl ethers (PBDEs) on airplanes, we measured PBDE concentrations in air samples collected in the cabin air at cruising altitudes and used Bayesian Decision Analysis (BDA) to evaluate the likelihood of inhalation exposure to result in the average daily dose (ADD) of a member of the flight crew to exceed EPA Reference Doses (RfDs), accounting for all other aircraft and non-aircraft exposures. A total of 59 air samples were collected from different aircraft and analyzed for four PBDE congeners-BDE 47, 99, 100 and 209 (a subset were also analyzed for BDE 183). For congeners with a published RfD, high estimates of ADD were calculated for all non-aircraft exposure pathways and non-inhalation exposure onboard aircraft; inhalation exposure limits were then derived based on the difference between the RfD and ADDs for all other exposure pathways. The 95th percentile measured concentrations of PBDEs in aircraft air were <1% of the derived inhalation exposure limits. Likelihood probabilities of 95th percentile exposure concentrations >1% of the defined exposure limit were zero for all congeners with published RfDs.

  19. Biomimetic air sampling for detection of low concentrations of molecules and bioagents : LDRD 52744 final report.

    SciTech Connect

    Hughes, Robert Clark

    2003-12-01

    Present methods of air sampling for low concentrations of chemicals like explosives and bioagents involve noisy and power hungry collectors with mechanical parts for moving large volumes of air. However there are biological systems that are capable of detecting very low concentrations of molecules with no mechanical moving parts. An example is the silkworm moth antenna which is a highly branched structure where each of 100 branches contains about 200 sensory 'hairs' which have dimensions of 2 microns wide by 100 microns long. The hairs contain about 3000 pores which is where the gas phase molecules enter the aqueous (lymph) phase for detection. Simulations of diffusion of molecules indicate that this 'forest' of hairs is 'designed' to maximize the extraction of the vapor phase molecules. Since typical molecules lose about 4 decades in diffusion constant upon entering the liquid phase, it is important to allow air diffusion to bring the molecule as close to the 'sensor' as possible. The moth acts on concentrations as low as 1000 molecules per cubic cm. (one part in 1e16). A 3-D collection system of these dimensions could be fabricated by micromachining techniques available at Sandia. This LDRD addresses the issues involved with extracting molecules from air onto micromachined structures and then delivering those molecules to microsensors for detection.

  20. Air conditioning impact on the dynamics of radon and its daughters concentration.

    PubMed

    Kozak, Krzysztof; Grządziel, Dominik; Połednik, Bernard; Mazur, Jadwiga; Dudzińska, Marzenna R; Mroczek, Mariusz

    2014-12-01

    Radon and its decay products are harmful pollutants present in indoor air and are responsible for the majority of the effective dose due to ionising radiation that people are naturally exposed to. The paper presents the results of the series of measurements of radon and its progeny (in unattached and attached fractions) as well as indoor air parameters: temperature, relative humidity, number and mass concentrations of fine aerosol particles. The measurements were carried out in the auditorium (lecture hall), which is an indoor air quality laboratory, in controlled conditions during two periods of time: when air conditioning (AC) was switched off (unoccupied auditorium) and when it was switched on (auditorium in normal use). The significant influence of AC and of students' presence on the dynamics of radon and its progeny was confirmed. A decrease in the mean value of radon and its attached progeny was found when AC was working. The mean value of radon equilibrium factor F was also lower when AC was working (0.49) than when it was off (0.61). The linear correlations were found between attached radon progeny concentration and particle number and mass concentration only when the AC was switched off. This research is being conducted with the aim to study the variability of radon equilibrium factor F which is essential to determine the effective dose due to radon and its progeny inhalation.

  1. Air concentrations of PBDEs on in-flight airplanes and assessment of flight crew inhalation exposure.

    PubMed

    Allen, Joseph G; Sumner, Ann Louise; Nishioka, Marcia G; Vallarino, Jose; Turner, Douglas J; Saltman, Hannah K; Spengler, John D

    2013-07-01

    To address the knowledge gaps regarding inhalation exposure of flight crew to polybrominated diphenyl ethers (PBDEs) on airplanes, we measured PBDE concentrations in air samples collected in the cabin air at cruising altitudes and used Bayesian Decision Analysis (BDA) to evaluate the likelihood of inhalation exposure to result in the average daily dose (ADD) of a member of the flight crew to exceed EPA Reference Doses (RfDs), accounting for all other aircraft and non-aircraft exposures. A total of 59 air samples were collected from different aircraft and analyzed for four PBDE congeners-BDE 47, 99, 100 and 209 (a subset were also analyzed for BDE 183). For congeners with a published RfD, high estimates of ADD were calculated for all non-aircraft exposure pathways and non-inhalation exposure onboard aircraft; inhalation exposure limits were then derived based on the difference between the RfD and ADDs for all other exposure pathways. The 95th percentile measured concentrations of PBDEs in aircraft air were <1% of the derived inhalation exposure limits. Likelihood probabilities of 95th percentile exposure concentrations >1% of the defined exposure limit were zero for all congeners with published RfDs. PMID:22739680

  2. Air conditioning impact on the dynamics of radon and its daughters concentration.

    PubMed

    Kozak, Krzysztof; Grządziel, Dominik; Połednik, Bernard; Mazur, Jadwiga; Dudzińska, Marzenna R; Mroczek, Mariusz

    2014-12-01

    Radon and its decay products are harmful pollutants present in indoor air and are responsible for the majority of the effective dose due to ionising radiation that people are naturally exposed to. The paper presents the results of the series of measurements of radon and its progeny (in unattached and attached fractions) as well as indoor air parameters: temperature, relative humidity, number and mass concentrations of fine aerosol particles. The measurements were carried out in the auditorium (lecture hall), which is an indoor air quality laboratory, in controlled conditions during two periods of time: when air conditioning (AC) was switched off (unoccupied auditorium) and when it was switched on (auditorium in normal use). The significant influence of AC and of students' presence on the dynamics of radon and its progeny was confirmed. A decrease in the mean value of radon and its attached progeny was found when AC was working. The mean value of radon equilibrium factor F was also lower when AC was working (0.49) than when it was off (0.61). The linear correlations were found between attached radon progeny concentration and particle number and mass concentration only when the AC was switched off. This research is being conducted with the aim to study the variability of radon equilibrium factor F which is essential to determine the effective dose due to radon and its progeny inhalation. PMID:24375376

  3. A mutant of Arabidopsis thaliana that exhibits chlorosis in air but not in atmospheres enriched in CO sub 2

    SciTech Connect

    Artus, N.N.; Somerville, C. )

    1988-05-01

    A mutant of Arabidopsis thaliana (L.) Heynh. which requires a high concentration (2% by volume) of atmospheric CO{sub 2} for growth has been isolated. Unlike previous mutants of this type, this line does not have any apparent defect in photosynthetic CO{sub 2}-fixation, photorespiration, or photosynthetic electron transport. The mutant is abnormally susceptible to pigment bleaching in air but not in 2% CO{sub 2}. The presence of normal or above-normal levels of antioxidants, carotenoids, and enzymes involved in reactive oxygen detoxification suggests that the mutant is equipped to detoxify activated oxygen species. Although it was not possible to establish a biochemical basis for the lesion, the properties of the mutant suggest the existence of a previously unidentified role for CO{sub 2}.

  4. The Impact of Future Emissions Changes on Air Pollution Concentrations and Related Human Health Effects

    NASA Astrophysics Data System (ADS)

    Mikolajczyk, U.; Suppan, P.; Williams, M.

    2015-12-01

    Quantification of potential health benefits of reductions in air pollution on the local scale is becoming increasingly important. The aim of this study is to conduct health impact assessment (HIA) by utilizing regionally and spatially specific data in order to assess the influence of future emission scenarios on human health. In the first stage of this investigation, a modeling study was carried out using the Weather Research and Forecasting (WRF) model coupled with Chemistry to estimate ambient concentrations of air pollutants for the baseline year 2009, and for the future emission scenarios in southern Germany. Anthropogenic emissions for the baseline year 2009 are derived from the emission inventory provided by the Netherlands Organization of Applied Scientific Research (TNO) (Denier van der Gon et al., 2010). For Germany, the TNO emissions were replaced by gridded emission data with a high spatial resolution of 1/64 x 1/64 degrees. Future air quality simulations are carried out under different emission scenarios, which reflect possible energy and climate measures in year 2030. The model set-up included a nesting approach, where three domains with horizontal resolution of 18 km, 6 km and 2 km were defined. The simulation results for the baseline year 2009 are used to quantify present-day health burdens. Concentration-response functions (CRFs) for PM2.5 and NO2 from the WHO Health risks of air Pollution in Europe (HRAPIE) project were applied to population-weighted mean concentrations to estimate relative risks and hence to determine numbers of attributable deaths and associated life-years lost. In the next step, future health impacts of projected concentrations were calculated taking into account different emissions scenarios. The health benefits that we assume with air pollution reductions can be used to provide options for future policy decisions to protect public health.

  5. Detonation propagation in hydrogen-air mixtures with transverse concentration gradients

    NASA Astrophysics Data System (ADS)

    Boeck, L. R.; Berger, F. M.; Hasslberger, J.; Sattelmayer, T.

    2016-03-01

    The influence of transverse concentration gradients on detonation propagation in H_2-air mixtures is investigated experimentally in a wide parameter range. Detonation fronts are characterized by means of high-speed shadowgraphy, OH* imaging, pressure measurements, and soot foils. Steep concentration gradients at low average H_2 concentrations lead to single-headed detonations. A maximum velocity deficit compared to the Chapman-Jouguet velocity of 9 % is observed. Significant amounts of mixture seem to be consumed by turbulent deflagration behind the leading detonation. Wall pressure measurements show high local pressure peaks due to strong transverse waves caused by the concentration gradients. Higher average H_2 concentrations or weaker gradients allow for multi-headed detonation propagation.

  6. Concentrations and patterns of polychlorinated naphthalenes in urban air in Beijing, China.

    PubMed

    Xue, Lingnan; Zhang, Lifei; Yan, Yan; Dong, Liang; Huang, Yeru; Li, Xiaoxiu

    2016-11-01

    Air samples were collected, using a high-volume air sampler, at an urban site in Beijing from April 2014 to March 2015. The polychlorinated naphthalene (PCN) concentration in the atmosphere in each season was determined. The total PCN (total target tri- to octachloronaphthalene congeners) concentrations were 1.99-19.0 pg/m(3), and the mean was 7.20 pg/m(3). The PCN concentrations were higher in fall than summer, indicating that the concentrations varied significantly over time. The trichloronaphthalene homolog was the predominant PCN homolog in all four seasons. The PCN toxic equivalent (TEQ) concentrations were 0.42-6.89 fg/m(3), and the mean was 1.74 fg/m(3). The CN-66/67 and CN-73 congeners were the predominant contributors to the TEQ concentrations. The mean seasonal TEQ concentration decreased in the order fall (3.18 fg/m(3)) > winter (1.41 fg/m(3)) > summer (1.11 fg/m(3)) > spring (1.03 fg/m(3)). The TEQ concentrations and the PCN concentrations did not follow the same seasonal trends, but the highest TEQ and PCN concentrations were both found in fall. Correlation analysis, ratio analysis, and principal component analysis were used to investigate the sources of PCNs to the Beijing atmosphere. The results suggested that combustion processes may be the main sources of PCNs to the Beijing atmosphere.

  7. Concentrations and patterns of polychlorinated naphthalenes in urban air in Beijing, China.

    PubMed

    Xue, Lingnan; Zhang, Lifei; Yan, Yan; Dong, Liang; Huang, Yeru; Li, Xiaoxiu

    2016-11-01

    Air samples were collected, using a high-volume air sampler, at an urban site in Beijing from April 2014 to March 2015. The polychlorinated naphthalene (PCN) concentration in the atmosphere in each season was determined. The total PCN (total target tri- to octachloronaphthalene congeners) concentrations were 1.99-19.0 pg/m(3), and the mean was 7.20 pg/m(3). The PCN concentrations were higher in fall than summer, indicating that the concentrations varied significantly over time. The trichloronaphthalene homolog was the predominant PCN homolog in all four seasons. The PCN toxic equivalent (TEQ) concentrations were 0.42-6.89 fg/m(3), and the mean was 1.74 fg/m(3). The CN-66/67 and CN-73 congeners were the predominant contributors to the TEQ concentrations. The mean seasonal TEQ concentration decreased in the order fall (3.18 fg/m(3)) > winter (1.41 fg/m(3)) > summer (1.11 fg/m(3)) > spring (1.03 fg/m(3)). The TEQ concentrations and the PCN concentrations did not follow the same seasonal trends, but the highest TEQ and PCN concentrations were both found in fall. Correlation analysis, ratio analysis, and principal component analysis were used to investigate the sources of PCNs to the Beijing atmosphere. The results suggested that combustion processes may be the main sources of PCNs to the Beijing atmosphere. PMID:27497350

  8. Seasonal change of persistent organic pollutant concentrations in air at Niigata area, Japan.

    PubMed

    Murayama, Hitoshi; Takase, Yuuya; Mitobe, Hideko; Mukai, Hiroyuki; Ohzeki, Toshiharu; Shimizu, Ken-ichi; Kitayama, Yoshie

    2003-07-01

    The concentrations of persistent organic pollutants (POPs), such as HCB, alpha-, beta-, gamma- and delta-HCH, trans- and cis-chlordane (t-CHL, c-CHL), DDE, DDD and DDT, in ambient air have been measured at five sampling points in Niigata area, Japan (Niigata, Maki, Tsubame, Jouzo and Yahiko) during the period from September 1999 to November 2001. HCB, alpha-HCH, t-CHL and c-CHL showed higher concentrations than the other chemicals in all locations. All the POPs except t-CHL and c-CHL collected at urban sites of the Niigata Plain was almost the same in their concentration levels. Higher concentrations of t-CHL and c-CHL in residential areas should be attributed to the past usage of the chemical as a termiticide. At Yahiko (remote site), most of the POPs showed lower concentrations than those measured at the other sampling sites, although alpha-HCH and gamma-HCH were comparable with the concentrations found at the other sampling sites. All POPs except alpha-HCH and gamma-HCH tend to decrease 41-80% in their concentrations from 2000 to 2001. The lower POPs concentrations in winter and the higher POPs concentrations in summer at every sampling point can be partly explained by temperature differences. Applying the equation of the logarithm of the POP partial pressure in air versus reciprocal temperature (lnPa=m/T+b) to our data, linear relations were observed. HCB gave a poor linearity and the smallest slope, while beta-HCH, t-CHL and c-CHL gave good linearities and large slopes in the equation. The results suggest that HCB level is influenced by not only the emission from terrestrial sources but the global-scale background pollution. A peculiar observation is that beta-HCH concentration measured in our study showed large temperature dependence, indicating there could be a source of contamination in the surrounding areas. PMID:12738282

  9. Assessment of regional air quality by a concentration-dependent Pollution Permeation Index

    NASA Astrophysics Data System (ADS)

    Liang, Chun-Sheng; Liu, Huan; He, Ke-Bin; Ma, Yong-Liang

    2016-10-01

    Although air quality monitoring networks have been greatly improved, interpreting their expanding data in both simple and efficient ways remains challenging. Therefore, needed are new analytical methods. We developed such a method based on the comparison of pollutant concentrations between target and circum areas (circum comparison for short), and tested its applications by assessing the air pollution in Jing-Jin-Ji, Yangtze River Delta, Pearl River Delta and Cheng-Yu, China during 2015. We found the circum comparison can instantly judge whether a city is a pollution permeation donor or a pollution permeation receptor by a Pollution Permeation Index (PPI). Furthermore, a PPI-related estimated concentration (original concentration plus halved average concentration difference) can be used to identify some overestimations and underestimations. Besides, it can help explain pollution process (e.g., Beijing’s PM2.5 maybe largely promoted by non-local SO2) though not aiming at it. Moreover, it is applicable to any region, easy-to-handle, and able to boost more new analytical methods. These advantages, despite its disadvantages in considering the whole process jointly influenced by complex physical and chemical factors, demonstrate that the PPI based circum comparison can be efficiently used in assessing air pollution by yielding instructive results, without the absolute need for complex operations.

  10. BTEX in indoor air of waterpipe cafés: Levels and factors influencing their concentrations.

    PubMed

    Hazrati, Sadegh; Rostami, Roohollah; Fazlzadeh, Mehdi

    2015-08-15

    BTEX (benzene, toluene, ethylbenzene and xylene) concentrations, factors affecting their levels, and the exposure risks related to these compounds were studied in waterpipe (Ghalyun/Hookah) cafés of Ardabil city in Islamic Republic of Iran. 81 waterpipe cafés from different districts of Ardabil city were selected and their ambient air was monitored for BTEX compounds. Air samples were taken from standing breathing zone of employees, ~150 cm above the ground level, and were analyzed using GC-FID. In each case, the types of smoked tobacco (regular, fruit flavored), types of ventilation systems (natural/artificial), and the floor level at which the café was located were investigated. A high mean concentration of 4.96±2.63 mg/m(3) corresponding to long term exposure to benzene-related cancer risk of 4314×10(-6) was estimated. The levels of the remaining compounds were lower than the national guideline limits, but their hazard quotients (HQ) for long term exposure to ethylbenzene (1.15) and xylene (17.32) exceeded the HQ unit value. Total hazard indices (HI) of 63.23 were obtained for non-cancer risks. Type of the smoked tobacco was the most important factor influencing BTEX concentrations in the cafés. BTEX concentrations in indoor ambient air of Ardabil waterpipe cafés were noticeably high, and therefore may pose important risks for human health on both short and long term exposures. PMID:25912530

  11. Quantile regression of indoor air concentrations of volatile organic compounds (VOC).

    PubMed

    Schlink, Uwe; Thiem, Alexander; Kohajda, Tibor; Richter, Matthias; Strebel, Kathrin

    2010-08-15

    There are many factors determining the concentration of volatile organic compounds (VOCs) in indoor air. On the basis of 601 population-based measurements we develop an explicit exposure model that includes factors, such as renovation, furniture, flat size, smoking, and education level of the occupants. As a novel method for the evaluation of concentrations of indoor air pollutants we use quantile regression, which has the advantages of robustness against non-Gaussian distributions (and outliers) and can adjust for unbalanced frequencies of observations. The applied bi- and multivariate quantile regressions provide (1) the VOC burden that is representative for the population of Leipzig, Germany, and (2) an inter-comparison of the effects of the studied factors and their levels. As a result, we find strong evidence for factors of general impact on most VOC components, such as the season, flooring, the type of the room, and the size of the apartment. Other impact factors are very specific to the VOC components. For example, wooden flooring (parquet) and new furniture increase the concentration of terpenes as well as the modifying factors high education and sampling in the child's room. Smokers ventilate their flats in an extent that in general reduces the VOC concentrations, except for benzene (contained in tobacco smoke), which is still higher in smoking than in non-smoking flats. Very often dampness is associated with an increased VOC burden in indoor air. An investigation of mixtures emphasises a high burden of co-occurring terpenes in very small and very large apartments.

  12. Volatile organic compound concentrations in ambient air of Kaohsiung petroleum refinery in Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Tsai-Yin; Sree, Usha; Tseng, Sen-Hong; Chiu, Kong Hwa; Wu, Chien-Hou; Lo, Jiunn-Guang

    The air quality assessment for volatile organic compounds (VOC) was conducted in and around Chinese petroleum corporation (CPC) refinery at Kaohsiung, located in southern Taiwan, during 2001 by collecting air samples at 26 sites. Benzene and toluene were detected as the most abundant VOC by both gas chromatography and ultra-violet differential optical absorption spectroscopy (UV-DOAS) techniques. BTXE concentrations showed day and night variations at some of the sampling site. The highest among the 26 sites for total concentration of VOC at CPC was 2506 ppbv near waste burning stack. High concentrations of VOC were also detected at the wastewater management area and the east gate of the plant. The values were 10-18 times higher than those probed in Kaohsiung city. The meteorological parameters such as wind speed and direction played vital roles in the distribution of ambient air VOC concentrations and affected the petrochemical complex emissions. The application of UV-DOAS for online monitoring of criteria pollutants appears feasible though the accuracy of the technique is not fully controlled.

  13. Assessment of regional air quality by a concentration-dependent Pollution Permeation Index

    PubMed Central

    Liang, Chun-Sheng; Liu, Huan; He, Ke-Bin; Ma, Yong-Liang

    2016-01-01

    Although air quality monitoring networks have been greatly improved, interpreting their expanding data in both simple and efficient ways remains challenging. Therefore, needed are new analytical methods. We developed such a method based on the comparison of pollutant concentrations between target and circum areas (circum comparison for short), and tested its applications by assessing the air pollution in Jing-Jin-Ji, Yangtze River Delta, Pearl River Delta and Cheng-Yu, China during 2015. We found the circum comparison can instantly judge whether a city is a pollution permeation donor or a pollution permeation receptor by a Pollution Permeation Index (PPI). Furthermore, a PPI-related estimated concentration (original concentration plus halved average concentration difference) can be used to identify some overestimations and underestimations. Besides, it can help explain pollution process (e.g., Beijing’s PM2.5 maybe largely promoted by non-local SO2) though not aiming at it. Moreover, it is applicable to any region, easy-to-handle, and able to boost more new analytical methods. These advantages, despite its disadvantages in considering the whole process jointly influenced by complex physical and chemical factors, demonstrate that the PPI based circum comparison can be efficiently used in assessing air pollution by yielding instructive results, without the absolute need for complex operations. PMID:27731344

  14. Ambient concentrations of aldehydes in relation to Beijing Olympic air pollution control measures

    NASA Astrophysics Data System (ADS)

    Gong, J. C.; Zhu, T.; Hu, M.; Zhang, L. W.; Cheng, H.; Zhang, L.; Tong, J.; Zhang, J.

    2010-08-01

    Aldehydes are ubiquitous constituents of the atmosphere. Their concentrations are elevated in polluted urban atmospheres. The present study was carried out to characterize three aldehydes of most health concern (formaldehyde, acetaldehyde, and acrolein) in a central Beijing site in the summer and early fall of 2008 (from June to October). Measurements were made before, during, and after the Beijing Olympics to examine whether the air pollution control measures implemented to improve Beijing's air quality during the Olympics had any impact on concentrations of the three aldehydes. Average concentrations of formaldehyde, acetaldehyde and acrolein were 29.34 ± 15.12 μg/m3, 27.09 ± 15.74 μg/m3 and 2.32 ± 0.95 μg/m3, respectively, for the entire period of measurements, all being the highest among the levels measured in cities around the world in photochemical smog seasons. Among the three measured aldehydes, only acetaldehyde had a substantially reduced mean concentration during the Olympic air pollution control period compared to the pre-Olympic period. Formaldehyde and acrolein followed the changing pattern of temperature and were each significantly correlated with ozone (a secondary product of photochemical reactions). In contrast, acetaldehyde was significantly correlated with several pollutants emitted mainly from local emission sources (e.g., NO2, CO, and PM2.5). These findings suggest that local direct emissions had a larger impact on acetaldehyde than formaldehyde and acrolein.

  15. Persistence analysis of extreme CO, NO2 and O3 concentrations in ambient air of Delhi

    NASA Astrophysics Data System (ADS)

    Chelani, Asha B.

    2012-05-01

    Persistence analysis of air pollutant concentration and corresponding exceedance time series is carried out to examine for temporal evolution. For this purpose, air pollutant concentrations, namely, CO, NO2 and O3 observed during 2000-2009 at a traffic site in Delhi are analyzed using detrended fluctuation analysis. Two types of extreme values are analyzed; exceeded concentrations to a threshold provided by national pollution controlling agency and time interval between two exceedances. The time series of three pollutants is observed to possess persistence property whereas the extreme value time series of only primary pollutant concentrations is found to be persistent. Two time scaling regions are observed to be significant in extreme time series of CO and NO2, mainly attributed to implementation of CNG in vehicles. The presence of persistence in three pollutant concentration time series is linked to the property of self-organized criticality. The observed persistence in the time interval between two exceeded levels is a matter of concern as persistent high concentrations can trigger health problems.

  16. Contribution of ship emissions to the concentration and deposition of air pollutants in Europe

    NASA Astrophysics Data System (ADS)

    Aksoyoglu, S.; Prévôt, A. S. H.; Baltensperger, U.

    2015-11-01

    Emissions from the marine transport sector are one of the least regulated anthropogenic emission sources and contribute significantly to air pollution. Although strict limits were introduced recently for the maximum sulfur content in marine fuels in the SECAs (sulfur emission control areas) and in the EU ports, sulfur emissions outside the SECAs and emissions of other components in all European maritime areas have continued to increase in the last two decades. We have used the air quality model CAMx with and without ship emissions for the year 2006 to determine the effects of international shipping on the annual as well as seasonal concentrations of ozone, primary and secondary components of PM2.5 and the dry and wet deposition of nitrogen and sulfur compounds in Europe. Our results suggest that emissions from international shipping affect the air quality in northern and southern Europe differently and their contributions to the air concentrations vary seasonally. The largest changes in pollutant concentrations due to ship emissions were predicted for summer. Increased concentrations of the primary particle mass were found only along the shipping routes whereas concentrations of the secondary pollutants were affected over a larger area. Concentrations of particulate sulfate increased due to ship emissions in the Mediterranean (up to 60 %), in the English Channel and the North Sea (30-35 %) while increases in particulate nitrate levels were found especially in the north, around the Benelux area (20 %) where there were high NH3 land-based emissions. Our model results showed that not only the atmospheric concentrations of pollutants are affected by ship emissions, but also depositions of nitrogen and sulfur compounds increase significantly along the shipping routes. NOx emissions from the ships especially in the English Channel and the North Sea, cause a decrease in the dry deposition of reduced nitrogen at source regions by moving it from the gas-phase to the

  17. MODELING AIR TOXICS AND PM 2.5 CONCENTRATION FIELDS AS A MEANS FOR FACILITATING HUMAN EXPOSURE ASSESSMENTS

    EPA Science Inventory

    The capability of the US EPA Models-3/Community Multiscale Air Quality (CMAQ) modeling system is extended to provide gridded ambient air quality concentration fields at fine scales. These fields will drive human exposure to air toxics and fine particulate matter (PM2.5) models...

  18. Soil carbon storage and N{sub 2}O emissions from wheat agroecosystems as affected by free-air CO{sub 2} enrichment (FACE) and nitrogen treatments. Final Report - February 12, 1999

    SciTech Connect

    S. W. Leavitt; A. D. Matthias; T. L. Thompson; R. A. Rauschkolb

    1999-02-17

    Rising atmospheric CO{sub 2} concentrations have prompted concern about response of plants and crops to future elevated CO{sub 2} levels, and particularly the extent to which ecosystems will sequester carbon and thus impact the rate of rise of CO{sub 2} concentrations. Free-air CO{sub 2} enrichment (FACE) experimentation was used with wheat agroecosystems for two growing seasons to assess effects of CO{sub 2} and soil nitrogen. Over 20 researchers on this experiment variously examined plant production and grain yield, phenology, length of growing season, water-use efficiency ecosystem production, below ground processes (eg, root and microbial activity, carbon and nitrogen cycling), etc.

  19. Influence of invasive earthworm activity on carbon dynamics in soils from the Aspen Free Air CO2 Enrichment Experiment

    NASA Astrophysics Data System (ADS)

    Filley, T. R.; Top, S. M.; Hopkins, F. M.

    2010-12-01

    The influence of CO2-driven increase in net primary productivity on soil organic carbon accrual has received considerable emphasis in ecological literature with conclusions varying from positive, to neutral, to negative. What has been understudied is the coupled role of soil fauna, such as earthworms, in controlling the ultimate fate of new above and below ground plant carbon under elevated CO2. Such considerations are particularly relevant considering that in most northern North American forests earthworms are an exotic organism known to cause significant changes to forest floor chemistry and soil structure, possibly increasing nutrient loss from both soil and leaf litter and mixing litter and humus deep into the mineral soil. The impact of these exotic earthworms on overall soil carbon stabilization is largely unknown but likely a function of both species composition and edaphic soil properties. In this paper we present the initial results of a carbon isotope study (13C, 14C) conducted at the Aspen free air CO2 enrichment (FACE) site, Rhinelander, WI, USA to track allocation and redistribution within the soil of plant litter and root carbon (bulk and biopolymer). Along with litter and soil to 25 cm depth, earthworm populations were quantified, and their gut contents collected for isotopic and plant biopolymer chemistry analysis. Contributions of root vs. leaf input to soil and earthworm fecal matter were derived from differences in the chemical and isotope composition of alkaline CuO-derived lignin and substituted fatty acids (SFA) from cutin and suberin. Our investigation demonstrates the presence of invasive European earthworms, of both litter and surface soil dwelling (epigeic) and deep soil dwelling (endogeic) varieties, whose abundance increases under elevated CO2 conditions. Additionally, the different species show selective vertical movement of new and pre-FACE plant biopolymers indicating dynamics in root and leaf decomposition and burial (down to 30 cm

  20. Concentration and risk assessment of phthalates present in indoor air from newly decorated apartments

    NASA Astrophysics Data System (ADS)

    Pei, X. Q.; Song, M.; Guo, M.; Mo, F. F.; Shen, X. Y.

    2013-04-01

    Phthalate esters (PAEs) are ubiquitous in the indoor environment, owing to their use in consumer products. People spend a considerable amount of time indoors. As a result, human exposure to indoor contaminants is of great concern. People are exposed to phthalates through inhalation and dermal absorption of indoor air. In this study, the concentrations, characteristics and carcinogenic risks of gas-phase and particle-phase phthalates in indoor air from bedroom, living room and study room of 10 newly decorated apartments in Hangzhou, China were first investigated. The mean concentration of phthalates (gas-phase and particle-phase) present in household air was 12 096.4 ng m-3, of which diethyl phthalate (DEP), butylbenzyl phthalate (BBP) and di(2-ethylhexyl) phthalate (DEHP) were the most abundant compounds with concentrations of 2290 ng m-3, 3975 ng m-3 and 2437 ng m-3, respectively, totally accounting for 72.0% of ∑6PAEs. Contamination levels of phthalates varied in different compartments. The concentration of phthalates was the highest 17 363.7 ng m-3 in living room, followed with 11 389.5 ng m-3 in study room, and the lowest 9739.1 ng m-3 in bedroom. It was also found that phthalates mainly accumulated in gaseous form in household air. DEHP posed the greatest health risk to children aged 1-2. Carcinogenic risk of DEHP was evaluated to be 3.912 × 10-5, and was 39 times higher than the limit set by the U.S. EPA.

  1. Particulate matter concentrations in residences: an intervention study evaluating stand-alone filters and air conditioners

    PubMed Central

    Batterman, S.; Du, L.; Mentz, G.; Mukherjee, B.; Parker, E.; Godwin, C.; Chin, J.-Y.; O'Toole, A.; Robins, T.; Rowe, Z.; Lewis, T.

    2014-01-01

    This study, a randomized controlled trial, evaluated the effectiveness of free-standing air filters and window air conditioners (ACs) in 126 low-income households of children with asthma. Households were randomized into a control group, a group receiving a free-standing HEPA filter placed in the child's sleeping area, and a group receiving the filter and a window-mounted AC. Indoor air quality (IAQ) was monitored for week-long periods over three to four seasons. High concentrations of particulate matter (PM) and carbon dioxide were frequently seen. When IAQ was monitored, filters reduced PM levels in the child's bedroom by an average of 50%. Filter use varied greatly among households and declined over time, for example, during weeks when pollutants were monitored, filter use was initially high, averaging 84 ± 27%, but dropped to 63 ± 33% in subsequent seasons. In months when households were not visited, use averaged only 34 ± 30%. Filter effectiveness did not vary in homes with central or room ACs. The study shows that measurements over multiple seasons are needed to characterize air quality and filter performance. The effectiveness of interventions using free-standing air filters depends on occupant behavior, and strategies to ensure filter use should be an integral part of interventions. PMID:22145709

  2. Natural ³⁷Ar concentrations in soil air: implications for monitoring underground nuclear explosions.

    PubMed

    Riedmann, Robin A; Purtschert, Roland

    2011-10-15

    For on-site inspections (OSI) under the Comprehensive Nuclear-Test-Ban Treaty (CTBT) measurement of the noble gas ³⁷Ar is considered an important technique. ³⁷Ar is produced underground by neutron activation of Calcium by the reaction ⁴⁰Ca(n,α)³⁷Ar. The naturally occurring equilibrium ³⁷Ar concentration balance in soil air is a function of an exponentially decreasing production rate from cosmic ray neutrons with increasing soil depth, diffusive transport in the soil air, and radioactive decay (T(1/2): 35 days). In this paper for the first time, measurements of natural ³⁷Ar activities in soil air are presented. The highest activities of ~100 mBq m⁻³ air are 2 orders of magnitude larger than in the atmosphere and are found in 1.5-2.5 m depth. At depths > 8 m ³⁷Ar activities are < 20 mBq m⁻³ air. After identifying the main ³⁷Ar production and gas transport factors the expected global activity range distribution of ³⁷Ar in shallow subsoil (0.7 m below the surface) was estimated. In high altitude soils, with large amounts of Calcium and with low gas permeability, ³⁷Ar activities may reach values up to 1 Bq m⁻³.

  3. Determination of radionuclide concentrations in ground level air using the ASS-500 high volume sampler

    SciTech Connect

    Frenzel, E.; Arnold, D.; Wershofen, H.

    1996-06-01

    A method for determination of radionuclide concentrations in air aerosol samples collected by the high volume aerosol sampler ASS-500 was elaborated. The aerosol sampling station ASS-500 is a Stand alone, all-weather proofed instrument. It is designed for representative sampling of airborne radionuclides from ground level air at a height of about 1.5 m above ground level. The ASS-500 station enables continuous air monitoring both normal and emergency Situations. The collection of aerosols on the Petrianov FPP-15-1.5 type filter out of an air volume of about 100,000 m{sup 3} (sampling period 1 wk) or of about 250,000 m{sup 3} (sampling period 3 wk) admits accurate spectrometric low level measurements of natural and artificial radionuclides. The achieved detection limit is 0.5 {mu}Bq m{sup -3} and 0.2 {mu}Bq m{sup -3} for {sup 137}Cs, respectively. A new developed air flow Meter system allows to enhance the collected air volume to about 150,000 m{sup 3} per week and lowers the detection limit to <0.4 {mu}Bq m{sup -3} for {sup 137}Cs for weekly collected aerosol samples. In Poland the CLOR uses 9 Stations ASS-500 at different sites as atmospheric radioactivity control system. On the basis of spectrometric measurements of natural and artificial radionuclides in the collected aerosol samples at the different sites, CLOR establishes a weekly report about the radiological situation at Poland for responsible authorities. The very low achievable detection limit of the Station ASS-500 due 10 the high air flow fate and the long possible sampling period were the key argument for other government radiation protection authorities in Europe to introduce the Station ASS-500 into their low level radionuclide atmospheric monitoring programs (Austria, Belarus, France, Germany, Iceland, Spain, Switzerland, Ukraine).

  4. Groundwater level and nitrate concentration trends on Mountain Home Air Force Base, southwestern Idaho

    USGS Publications Warehouse

    Williams, Marshall L.

    2014-01-01

    Mountain Home Air Force Base in southwestern Idaho draws most of its drinking water from the regional aquifer. The base is located within the State of Idaho's Mountain Home Groundwater Management Area and is adjacent to the State's Cinder Cone Butte Critical Groundwater Area. Both areas were established by the Idaho Department of Water Resources in the early 1980s because of declining water levels in the regional aquifer. The base also is listed by the Idaho Department of Environmental Quality as a nitrate priority area. The U.S. Geological Survey, in cooperation with the U.S. Air Force, began monitoring wells on the base in 1985, and currently monitors 25 wells for water levels and 17 wells for water quality, primarily nutrients. This report provides a summary of water-level and nitrate concentration data collected primarily between 2001 and 2013 and examines trends in those data. A Regional Kendall Test was run to combine results from all wells to determine an overall regional trend in water level. Groundwater levels declined at an average rate of about 1.08 feet per year. Nitrate concentration trends show that 3 wells (18 percent) are increasing in nitrate concentration trend, 3 wells (18 percent) show a decreasing nitrate concentration trend, and 11 wells (64 percent) show no nitrate concentration trend. Six wells (35 percent) currently exceed the U.S. Environmental Protection Agency's maximum contaminant limit of 10 milligrams per liter for nitrate (nitrite plus nitrate, measured as nitrogen).

  5. 10 CFR Appendix A to Part 835 - Derived Air Concentrations (DAC) for Controlling Radiation Exposure to Workers at DOE Facilities

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Derived Air Concentrations (DAC) for Controlling Radiation... RADIATION PROTECTION Pt. 835, App. A Appendix A to Part 835—Derived Air Concentrations (DAC) for Controlling Radiation Exposure to Workers at DOE Facilities The data presented in appendix A are to be used...

  6. Air quality in postunification Erfurt, East Germany: associating changes in pollutant concentrations with changes in emissions.

    PubMed Central

    Ebelt, S; Brauer, M; Cyrys, J; Tuch, T; Kreyling, W G; Wichmann, H E; Heinrich, J

    2001-01-01

    The unification of East and West Germany in 1990 resulted in sharp decreases in emissions of major air pollutants. This change in air quality has provided an opportunity for a natural experiment to evaluate the health impacts of air pollution. We evaluated airborne particle size distribution and gaseous co-pollutant data collected in Erfurt, Germany, throughout the 1990s and assessed the extent to which the observed changes are associated with changes in the two major emission sources: coal burning for power production and residential heating, and motor vehicles. Continuous data for sulfur dioxide, total suspended particulates (TSP), nitric oxide, carbon monoxide, and meteorologic parameters were available for 1990-1999, and size-selective particle number and mass concentration measurements were made during winters of 1991 and 1998. We used hourly profiles of pollutants and linear regression analyses, stratified by year, weekday/weekend, and hour, using NO and SO(2) as markers of traffic- and heating-related combustion sources, respectively, to study the patterns of various particle size fractions. Supplementary data on traffic and heating-related sources were gathered to support hypotheses linking these sources with observed changes in ambient air pollution levels. Substantially decreased (19-91%) concentrations were observed for all pollutants, with the exception of particles in the 0.01-0.03 microm size range (representing the smallest ultrafine particles that were measured). The number concentration for these particles increased by 115% between 1991 and 1998. The ratio of these ultrafine particles to TSP also increased by more than 500%, indicating a dramatic change in the size distribution of airborne particles. Analysis of hourly concentration patterns indicated that in 1991, concentrations of SO(2) and larger particle sizes were related to residential heating with coal. These peaks were no longer evident in 1998 due to decreases in coal consumption and

  7. Variation and balance of positive air ion concentrations in a boreal forest

    NASA Astrophysics Data System (ADS)

    Hõrrak, U.; Aalto, P. P.; Salm, J.; Komsaare, K.; Tammet, H.; Mäkelä, J. M.; Laakso, L.; Kulmala, M.

    2008-02-01

    Air ions are characterized on the basis of measurements carried out in a boreal forest at the Hyytiälä SMEAR station, Finland, during the BIOFOR III campaign in spring 1999. The air ions were discriminated as small ions (charged molecular aggregates of the diameter of less than 2.5 nm), intermediate ions (charged aerosol particles of the diameter of 2.5-8 nm), and large ions (charged aerosol particles of the diameter of 8-20 nm). Statistical characteristics of the ion concentrations and the parameters of ion balance in the atmosphere are presented separately for the nucleation event days and non-event days. In the steady state, the ionization rate is balanced with the loss of small ions, which is expressed as the product of the small ion concentration and the ion sink rate. The widely known sinks of small ions are the recombination with small ions of opposite polarity and attachment to aerosol particles. The dependence of small ion concentration on the concentration of aerosol particles was investigated applying a model of the bipolar diffusion charging of particles by small ions. When the periods of relative humidity above 95% and wind speed less than 0.6 m s-1 were excluded, then the small ion concentration and the theoretically calculated small ion sink rate were closely negatively correlated (correlation coefficient -87%). However, an extra ion loss term of the same magnitude as the ion loss onto aerosol particles is needed for a quantitative explanation of the observations. This term is presumably due to the small ion deposition on coniferous forest. The hygroscopic growth correction of the measured aerosol particle size distributions was also found to be necessary for the proper estimation of the ion sink rate. In the case of nucleation burst events, the concentration of small positive ions followed the general balance equation, no extra ion loss in addition to the deposition on coniferous forest was detected, and the hypothesis of the conversion of ions

  8. Spatial and temporal distribution of pesticide air concentrations in Canadian agricultural regions

    NASA Astrophysics Data System (ADS)

    Yao, Yuan; Tuduri, Ludovic; Harner, Tom; Blanchard, Pierrette; Waite, Don; Poissant, Laurier; Murphy, Clair; Belzer, Wayne; Aulagnier, Fabien; Li, Yi-Fan; Sverko, Ed

    The Canadian Pesticide Air Sampling Campaign was initiated in 2003 to assess atmospheric levels of pesticides, especially currently used pesticides (CUPs) in agricultural regions across Canada. In the first campaign during the spring to summer of 2003, over 40 pesticides were detected. The spatial and temporal distribution of pesticides in the Canadian atmosphere was shown to reflect the pesticide usage in each region. Several herbicides including triallate, bromoxynil, MCPA, 2,4-D, dicamba, trifluralin and ethalfluralin were detected at highest levels at Bratt's Lake, SK in the prairie region. Strong relationships between air concentrations and dry depositions were observed at this site. Although no application occurred in the Canadian Prairies in 2003, high air concentrations of lindane ( γ-hexachlorocyclohexane) were still observed at Bratt's Lake and Hafford, SK. Two fungicides (chlorothalonil and metalaxyl) and two insecticides (endosulfan and carbofuran) were measured at highest levels at Kensington, PEI. Maximum concentrations of chlorpyrifos and metolachlor were found at St. Anicet, QC. The southern Ontario site, Egbert showed highest concentration of alachlor. Malathion was detected at the highest level at the west coast site, Abbotsford, BC. In case of legacy chlorinated insecticides, high concentrations of DDT, DDE and dieldrin were detected in British Columbia while α-HCH and HCB were found to be fairly uniform across the country. Chlordane was detected in Ontario, Québec and Prince Edward Island. This study demonstrates that the sources for the observed atmospheric occurrence of pesticides include local current pesticide application, volatilization of pesticide residues from soil and atmospheric transport. In many instances, these data represent the first measurements for certain pesticides in a given part of Canada.

  9. Benzo(a)pyrene in Europe: Ambient air concentrations, population exposure and health effects.

    PubMed

    Guerreiro, C B B; Horálek, J; de Leeuw, F; Couvidat, F

    2016-07-01

    This study estimated current benzo(a)pyrene (BaP) concentration levels, population exposure and potential health impacts of exposure to ambient air BaP in Europe. These estimates were done by combining the best available information from observations and chemical transport models through the use of spatial interpolation methods. Results show large exceedances of the European target value for BaP in 2012 over large areas, particularly in central-eastern Europe. Results also show large uncertainties in the concentration estimates in regions with a few or no measurement stations. The estimation of the population exposure to BaP concentrations and its health impacts was limited to 60% of the European population, covering only the modelled areas which met the data quality requirement for modelling of BaP concentrations set by the European directive 2004/107/EC. The population exposure estimate shows that 20% of the European population is exposed to BaP background ambient concentrations above the EU target value and only 7% live in areas with concentrations under the estimated acceptable risk level of 0.12 ng m(-3). This exposure leads to an estimated 370 lung cancer incidences per year, for the 60% of the European population included in the estimation. Emissions of BaP have increased in the last decade with the increase in emissions from household combustion of biomass. At the same time, climate mitigation policies are promoting the use of biomass burning for domestic heating. The current study shows that there is a need for more BaP measurements in areas of low measurement density, particularly where high concentrations are expected, e.g. in Romania, Bulgaria, and other Balkan states. Furthermore, this study shows that the health risk posed by PAH exposure calls for better coordination between air quality and climate mitigation policies in Europe.

  10. Enriched Air Nitrox Breathing Reduces Venous Gas Bubbles after Simulated SCUBA Diving: A Double-Blind Cross-Over Randomized Trial

    PubMed Central

    Souday, Vincent; Koning, Nick J.; Perez, Bruno; Grelon, Fabien; Mercat, Alain; Boer, Christa; Seegers, Valérie; Radermacher, Peter; Asfar, Pierre

    2016-01-01

    Objective To test the hypothesis whether enriched air nitrox (EAN) breathing during simulated diving reduces decompression stress when compared to compressed air breathing as assessed by intravascular bubble formation after decompression. Methods Human volunteers underwent a first simulated dive breathing compressed air to include subjects prone to post-decompression venous gas bubbling. Twelve subjects prone to bubbling underwent a double-blind, randomized, cross-over trial including one simulated dive breathing compressed air, and one dive breathing EAN (36% O2) in a hyperbaric chamber, with identical diving profiles (28 msw for 55 minutes). Intravascular bubble formation was assessed after decompression using pulmonary artery pulsed Doppler. Results Twelve subjects showing high bubble production were included for the cross-over trial, and all completed the experimental protocol. In the randomized protocol, EAN significantly reduced the bubble score at all time points (cumulative bubble scores: 1 [0–3.5] vs. 8 [4.5–10]; P < 0.001). Three decompression incidents, all presenting as cutaneous itching, occurred in the air versus zero in the EAN group (P = 0.217). Weak correlations were observed between bubble scores and age or body mass index, respectively. Conclusion EAN breathing markedly reduces venous gas bubble emboli after decompression in volunteers selected for susceptibility for intravascular bubble formation. When using similar diving profiles and avoiding oxygen toxicity limits, EAN increases safety of diving as compared to compressed air breathing. Trial Registration ISRCTN 31681480 PMID:27163253

  11. Inhalation of concentrated ambient air particles exacerbates myocardial ischemia in conscious dogs.

    PubMed Central

    Wellenius, Gregory A; Coull, Brent A; Godleski, John J; Koutrakis, Petros; Okabe, Kazunori; Savage, Sara T; Lawrence, Joy E; Murthy, G G Krishna; Verrier, Richard L

    2003-01-01

    Short-term increases in ambient air pollution have been associated with an increased incidence of acute cardiac events. We assessed the effect of inhalation exposure to concentrated ambient particles (CAPs) on myocardial ischemia in a canine model of coronary artery occlusion. Six mongrel dogs underwent thoracotomy for implantation of a vascular occluder around the left anterior descending coronary artery and tracheostomy to facilitate particulate exposure. After recovery (5-13 weeks), pairs of subjects were exposed for 6 hr/day on 3 or 4 consecutive days. Within each pair, one subject was randomly assigned to breathe CAPs on the second exposure day and filtered air at other times. The second subject breathed CAPs on the third exposure day and filtered air at other times. Immediately after each exposure, subjects underwent 5-min coronary artery occlusion. We determined ST-segment elevation, a measure of myocardial ischemia heart rate, and arrhythmia incidence during occlusion from continuous electrocardiograms. Exposure to CAPs (median, 285.7; range, 161.3-957.3 microg/m3) significantly (p = 0.007) enhanced occlusion-induced peak ST-segment elevation in precordial leads V4 (9.4 +/- 1.7 vs. 6.2 +/- 0.9 mm, CAPs vs. filtered air, respectively) and V5 (9.2 +/- 1.3 vs. 7.5 +/- 0.9 mm). ST-segment elevation was significantly correlated with the silicon concentration of the particles and other crustal elements possibly associated with urban street dust (p = 0.003 for Si). No associations were found with CAPs mass or number concentrations. Heart rate was not affected by CAPs exposure. These results suggest that exacerbation of myocardial ischemia during coronary artery occlusion may be an important mechanism of environmentally related acute cardiac events. PMID:12676590

  12. Sample Enrichment for Bioanalytical Assessment of Disinfected Drinking Water: Concentrating the Polar, the Volatiles, and the Unknowns.

    PubMed

    Stalter, Daniel; Peters, Leon I; O'Malley, Elissa; Tang, Janet Yat-Man; Revalor, Marion; Farré, Maria José; Watson, Kalinda; von Gunten, Urs; Escher, Beate I

    2016-06-21

    Enrichment methods used in sample preparation for the bioanalytical assessment of disinfected drinking water result in the loss of volatile and hydrophilic disinfection byproducts (DBPs) and hence likely tend to underestimate biological effects. We developed and evaluated methods that are compatible with bioassays, for extracting nonvolatile and volatile DBPs from chlorinated and chloraminated drinking water to minimize the loss of analytes. For nonvolatile DBPs, solid-phase extraction (SPE) with TELOS ENV as solid phase performed superior compared to ten other sorbents. SPE yielded >70% recovery of nonpurgeable adsorbable organic halogens (AOX). For volatile DBPs, cryogenic vacuum distillation performed unsatisfactorily. Purge and cold-trap with crushed ice serving as condensation nuclei achieved recoveries of 50-100% for trihalomethanes and haloacetonitriles and approximately 60-90% for purged AOX from tap water. We compared the purgeable versus the nonpurgeable fraction by combining purge-and-trap extraction with SPE. The purgeable DBP fraction enriched with the purge-and-trap method exerted a lower oxidative stress response in mammalian cells than the nonpurgeable DBPs enriched with SPE after purging, while contributions of both fractions to bacterial cytotoxicity was more variable. 37 quantified DBPs explained almost the entire AOX in the purge-and-trap extracts, but <16% in the SPE extracts demonstrating that the nonpurgeable fraction is dominated by unknown DBPs. PMID:27153244

  13. Sample Enrichment for Bioanalytical Assessment of Disinfected Drinking Water: Concentrating the Polar, the Volatiles, and the Unknowns.

    PubMed

    Stalter, Daniel; Peters, Leon I; O'Malley, Elissa; Tang, Janet Yat-Man; Revalor, Marion; Farré, Maria José; Watson, Kalinda; von Gunten, Urs; Escher, Beate I

    2016-06-21

    Enrichment methods used in sample preparation for the bioanalytical assessment of disinfected drinking water result in the loss of volatile and hydrophilic disinfection byproducts (DBPs) and hence likely tend to underestimate biological effects. We developed and evaluated methods that are compatible with bioassays, for extracting nonvolatile and volatile DBPs from chlorinated and chloraminated drinking water to minimize the loss of analytes. For nonvolatile DBPs, solid-phase extraction (SPE) with TELOS ENV as solid phase performed superior compared to ten other sorbents. SPE yielded >70% recovery of nonpurgeable adsorbable organic halogens (AOX). For volatile DBPs, cryogenic vacuum distillation performed unsatisfactorily. Purge and cold-trap with crushed ice serving as condensation nuclei achieved recoveries of 50-100% for trihalomethanes and haloacetonitriles and approximately 60-90% for purged AOX from tap water. We compared the purgeable versus the nonpurgeable fraction by combining purge-and-trap extraction with SPE. The purgeable DBP fraction enriched with the purge-and-trap method exerted a lower oxidative stress response in mammalian cells than the nonpurgeable DBPs enriched with SPE after purging, while contributions of both fractions to bacterial cytotoxicity was more variable. 37 quantified DBPs explained almost the entire AOX in the purge-and-trap extracts, but <16% in the SPE extracts demonstrating that the nonpurgeable fraction is dominated by unknown DBPs.

  14. [Airborne Fungal Aerosol Concentration and Distribution Characteristics in Air- Conditioned Wards].

    PubMed

    Zhang, Hua-ling; Feng, He-hua; Fang, Zi-liang; Wang, Ben-dong; Li, Dan

    2015-04-01

    The effects of airborne fungus on human health in the hospital environment are related to not only their genera and concentrations, but also their particle sizes and distribution characteristics. Moreover, the mechanisms of aerosols with different particle sizes on human health are different. Fungal samples were obtained in medicine wards of Chongqing using a six-stage sampler. The airborne fungal concentrations, genera and size distributions of all the sampling wards were investigated and identified in detail. Results showed that airborne fungal concentrations were not correlated to the diseases or personnel density, but were related to seasons, temperature, and relative humidity. The size distribution rule had roughly the same for testing wards in winter and summer. The size distributions were not related with diseases and seasons, the percentage of airborne fungal concentrations increased gradually from stage I to stage III, and then decreased dramatically from stage V to stage VI, in general, the size of airborne fungi was a normal distribution. There was no markedly difference for median diameter of airborne fungi which was less 3.19 μm in these wards. There were similar dominant genera in all wards. They were Aspergillus spp, Penicillium spp and Alternaria spp. Therefore, attention should be paid to improve the filtration efficiency of particle size of 1.1-4.7 μm for air conditioning system of wards. It also should be targeted to choose appropriate antibacterial methods and equipment for daily hygiene and air conditioning system operation management.

  15. Nitrogen potential recovery and concentration of ammonia from swine manure using electrodialysis coupled with air stripping.

    PubMed

    Ippersiel, D; Mondor, M; Lamarche, F; Tremblay, F; Dubreuil, J; Masse, L

    2012-03-01

    The practice of intensive animal production in certain areas has resulted in excessive manure production for the available regional land base. Consequently, there is a need to develop treatment technologies to recover the valuable nutrients that manure contains so that the resulting product can be transported and used as fertilizer on agricultural land. The project presented here used electrodialysis in a dilution/concentration configuration to transfer the manure ammonia in the diluate solution by electromigration to an adjacent solution separated by an ion-exchange membrane under the driving force of an electrical potential. Then, air stripping from the electrodialysis-obtained concentrate solution without pH modification was used to isolate the ammonia in an acidic solution. An optimal process operating voltage of 17.5 V was first determined on the basis of current efficiency and total energy consumption. During the process, the swine manure pH varied from 8.5 to 8.2, values favourable for NH(4)(+) electromigration. Total ammonia nitrogen reached 21,352 mg/L in the concentrate solution, representing approximately seven times the concentration in the swine manure. Further increases in concentration were limited by water transfer from the diluate solution due to electroosmosis and osmosis. Applying vacuum to the concentrate reservoir was found to be more efficient than direct concentrate solution aeration for NH(3) recuperation in the acid trap, given that the ammonia recuperated under vacuum represented 14.5% of the theoretical value of the NH(3) present in the concentrate solution as compared to 6.2% for aeration. However, an excessively low concentrate solution pH (8.6-8.3) limited NH(3)volatilization toward the acid trap. These results suggest that the concentrate solution pH needs to be raised to promote the volatile NH(3) form of total ammonia nitrogen.

  16. Seasonal variation in vertical volatile compounds air concentrations within a remote hemiboreal mixed forest

    NASA Astrophysics Data System (ADS)

    Noe, S. M.; Hüve, K.; Niinemets, Ü.; Copolovici, L.

    2011-05-01

    The vertical distribution of ambient biogenic volatile organic compounds (BVOC) concentrations within a hemiboreal forest canopy was investigated over a period of one year. Variability in temporal and spatial isoprene concentrations can be mainly explained by biogenic emissions from deciduous trees, ranging from 0.1 to 7.5 μg m-3. Monoterpene concentrations exceeded isoprene largely and ranged from 0.01 to 140 μg m-3 and during winter time anthropogenic contributions are likely. Variation in monoterpene concentrations found to be largest right above the ground and the vertical profile suggest a weak mixing leading to terpene accumulation in the lower canopy. Exceptionally high values were recorded during a heat wave in July 2010 with very high midday temperatures above 30 °C for several weeks. During summer months, monoterpene exceeded isoprene concentrations 6-fold and during winter 12-fold. The relative contribution of diverse monoterpene species to the ambient concentrations revealed a dominance of α-pinene in the lower and of limonene in the upper part of the canopy, both accounting for up to 70 % of the total monoterpene concentration during summer months. The main contributing monoterpene during wintertime was Δ3-carene accounting for 60 % of total monoterpene concentration in January. Possible biogenic monoterpene sources beside the foliage are the leaf litter, the soil and also resins exuding from stems. In comparison, the hemiboreal mixed forest canopy showed similar isoprene but higher monoterpene concentrations than the boreal forest and lower isoprene but substantially higher monoterpene concentrations than the temperate mixed forest canopies. These results have major implications for simulating air chemistry and secondary organic aerosol formation within and above hemiboreal forest canopies.

  17. Use of Free Air CO/sub 2/ Enrichment (FACE) to study effects of CO/sub 2/ on cotton: Preliminary summary report -- 1988

    SciTech Connect

    Biswas, P.K.; Hileman, D.R.; Bhattacharya, N.C.; Ghosh, P.P.

    1988-01-01

    In the summer of 1988, Tuskegee University, along with Brookhaven National Laboratory, Manhattan College, and USDA laboratories in Tallahassee, FL and Phoenix, AZ, participated in joint program to evaluate the feasibility of using a Free Air CO/sub 2/ Enrichment (FACE) system to conduct experiments on the effects of elevated CO/sub 2/ on cotton. The experiments were conducted in Yazoo City, MS, under the direction of the US Department of Energy, Carbon Dioxide Research Division. Tuskegee University's role in the project included the following objectives: (1)Soil moisture and nutrient analysis before planting and at harvest. (2) Photosynthesis and stomatal conductance measurements at ambient and enriched CO/sub 2/ atmosphere. (3) Leaf water potential measurements. (4) CO/sub 2/ distribution patterns in the FACE array. 12 figs., 14 tabs.

  18. VOCs Emissions from Multiple Wood Pellet Types and Concentrations in Indoor Air

    PubMed Central

    Soto-Garcia, Lydia; Ashley, William J.; Bregg, Sandar; Walier, Drew; LeBouf, Ryan; Hopke, Philip K.; Rossner, Alan

    2016-01-01

    Wood pellet storage safety is an important aspect for implementing woody biomass as a renewable energy source. When wood pellets are stored indoors in large quantities (tons) in poorly ventilated spaces in buildings, such as in basements, off-gassing of volatile organic compounds (VOCs) can significantly affect indoor air quality. To determine the emission rates and potential impact of VOC emissions, a series of laboratory and field measurements were conducted using softwood, hardwood, and blended wood pellets manufactured in New York. Evacuated canisters were used to collect air samples from the headspace of drums containing pellets and then in basements and pellet storage areas of homes and small businesses. Multiple peaks were identified during GC/MS and GC/FID analysis, and four primary VOCs were characterized and quantified: methanol, pentane, pentanal, and hexanal. Laboratory results show that total VOCs (TVOCs) concentrations for softwood (SW) were statistically (p < 0.02) higher than blended or hardwood (HW) (SW: 412 ± 25; blended: 203 ± 4; HW: 99 ± 8, ppb). The emission rate from HW was the fastest, followed by blended and SW, respectively. Emissions rates were found to range from 10−1 to 10−5 units, depending upon environmental factors. Field measurements resulted in airborne concentrations ranging from 67 ± 8 to 5000 ± 3000 ppb of TVOCs and 12 to 1500 ppb of aldehydes, with higher concentrations found in a basement with a large fabric bag storage unit after fresh pellet delivery and lower concentrations for aged pellets. These results suggest that large fabric bag storage units resulted in a substantial release of VOCs into the building air. Occupants of the buildings tested discussed concerns about odor and sensory irritation when new pellets were delivered. The sensory response was likely due to the aldehydes. PMID:27022205

  19. Effect of geocoding errors on traffic-related air pollutant exposure and concentration estimates.

    PubMed

    Ganguly, Rajiv; Batterman, Stuart; Isakov, Vlad; Snyder, Michelle; Breen, Michael; Brakefield-Caldwell, Wilma

    2015-01-01

    Exposure to traffic-related air pollutants is highest very near roads, and thus exposure estimates are sensitive to positional errors. This study evaluates positional and PM2.5 concentration errors that result from the use of automated geocoding methods and from linearized approximations of roads in link-based emission inventories. Two automated geocoders (Bing Map and ArcGIS) along with handheld GPS instruments were used to geocode 160 home locations of children enrolled in an air pollution study investigating effects of traffic-related pollutants in Detroit, Michigan. The average and maximum positional errors using the automated geocoders were 35 and 196 m, respectively. Comparing road edge and road centerline, differences in house-to-highway distances averaged 23 m and reached 82 m. These differences were attributable to road curvature, road width and the presence of ramps, factors that should be considered in proximity measures used either directly as an exposure metric or as inputs to dispersion or other models. Effects of positional errors for the 160 homes on PM2.5 concentrations resulting from traffic-related emissions were predicted using a detailed road network and the RLINE dispersion model. Concentration errors averaged only 9%, but maximum errors reached 54% for annual averages and 87% for maximum 24-h averages. Whereas most geocoding errors appear modest in magnitude, 5% to 20% of residences are expected to have positional errors exceeding 100 m. Such errors can substantially alter exposure estimates near roads because of the dramatic spatial gradients of traffic-related pollutant concentrations. To ensure the accuracy of exposure estimates for traffic-related air pollutants, especially near roads, confirmation of geocoordinates is recommended.

  20. Cleaning Products and Air Fresheners: Emissions and ResultingConcentrations of Glycol Ethers and Terpenoids

    SciTech Connect

    Singer, Brett C.; Destaillat, Hugo; Hodgson, Alfred T.; Nazaroff,William W.

    2005-08-01

    Experiments were conducted to quantify emissions and concentrations of glycol ethers and terpenoids from cleaning product and air freshener use in a 50-m{sup 3} room ventilated at {approx}0.5 h{sup -1}. Five cleaning products were applied full-strength (FS); three were additionally used in dilute solution. FS application of pine-oil cleaner (POC) yielded 1-h concentrations of 10-1300 {micro}g m{sup -3} for individual terpenoids, including {alpha}-terpinene (90-120), d-limonene (1000-1100), terpinolene (900-1300), and {alpha}-terpineol (260-700). One-hour concentrations of 2-butoxyethanol and/or dlimonene were 300-6000 {micro}g m{sup -3} after FS use of other products. During FS application including rinsing with sponge and wiping with towels, fractional emissions (mass volatilized/dispensed) of 2-butoxyethanol and d-limonene were 50-100% with towels retained, {approx}25-50% when towels were removed after cleaning. Lower fractions (2-11%) resulted from dilute use. Fractional emissions of terpenes from FS use of POC were {approx}35-70% with towels retained, 20-50% with towels removed. During floor cleaning with dilute solution of POC, 7-12% of dispensed terpenes were emitted. Terpene alcohols were emitted at lower fractions: 7-30% (FS, towels retained), 2-9% (FS, towels removed), and 2-5% (dilute). During air-freshener use, d-limonene, dihydromyrcenol, linalool, linalyl acetate, and {beta}-citronellol were emitted at 35-180 mg d{sup -1} over three days while air concentrations averaged 30-160 {micro}g m{sup -3}.

  1. Effect of geocoding errors on traffic-related air pollutant exposure and concentration estimates

    PubMed Central

    Ganguly, Rajiv; Batterman, Stuart; Isakov, Vlad; Snyder, Michelle; Breen, Michael; Brakefield-Caldwell, Wilma

    2015-01-01

    Exposure to traffic-related air pollutants is highest very near roads, and thus exposure estimates are sensitive to positional errors. This study evaluates positional and PM2.5 concentration errors that result from the use of automated geocoding methods and from linearized approximations of roads in link-based emission inventories. Two automated geocoders (Bing Map and ArcGIS) along with handheld GPS instruments were used to geocode 160 home locations of children enrolled in an air pollution study investigating effects of traffic-related pollutants in Detroit, Michigan. The average and maximum positional errors using the automated geocoders were 35 and 196 m, respectively. Comparing road edge and road centerline, differences in house-to-highway distances averaged 23 m and reached 82 m. These differences were attributable to road curvature, road width and the presence of ramps, factors that should be considered in proximity measures used either directly as an exposure metric or as inputs to dispersion or other models. Effects of positional errors for the 160 homes on PM2.5 concentrations resulting from traffic-related emissions were predicted using a detailed road network and the RLINE dispersion model. Concentration errors averaged only 9%, but maximum errors reached 54% for annual averages and 87% for maximum 24-h averages. Whereas most geocoding errors appear modest in magnitude, 5% to 20% of residences are expected to have positional errors exceeding 100 m. Such errors can substantially alter exposure estimates near roads because of the dramatic spatial gradients of traffic-related pollutant concentrations. To ensure the accuracy of exposure estimates for traffic-related air pollutants, especially near roads, confirmation of geocoordinates is recommended. PMID:25670023

  2. Pt-TiO2/MWCNTs Hybrid Composites for Monitoring Low Hydrogen Concentrations in Air

    PubMed Central

    Trocino, Stefano; Donato, Andrea; Latino, Mariangela; Donato, Nicola; Leonardi, Salvatore Gianluca; Neri, Giovanni

    2012-01-01

    Hydrogen is a valuable fuel for the next energy scenario. Unfortunately, hydrogen is highly flammable at concentrations higher than 4% in air. This aspect makes the monitoring of H2 leaks an essential issue for safety reasons, especially in the transportation field. In this paper, nanocomposites based on Pt-doped TiO2/multiwalled carbon nanotubes (MWCNTs) have been introduced as sensitive materials for H2 at low temperatures. Pt-TiO2/MWNTs nanocomposites with different composition have been prepared by a simple wet chemical procedure and their morphological, microstructural and electrical properties were investigated. Resistive thick-film devices have been fabricated printing the hybrid nanocomposites on alumina substrates provided with Pt interdigitated electrodes. Electrical tests in air have shown that embedding MWCNTs in the TiO2 matrix modify markedly the electrical conductivity, providing a means to decrease the resistance of the sensing layer. Pt acts as a catalytic additive. Pt-TiO2/MWNTs-based sensors were found to be sensitive to hydrogen at concentrations between 0.5 and 3% in air, satisfying the requisites for practical applications in hydrogen leak detection devices.

  3. Modeling breathing-zone concentrations of airborne contaminants generated during compressed air spray painting.

    PubMed

    Flynn, M R; Gatano, B L; McKernan, J L; Dunn, K H; Blazicko, B A; Carlton, G N

    1999-01-01

    This paper presents a mathematical model to predict breathing-zone concentrations of airborne contaminants generated during compressed air spray painting in cross-flow ventilated booths. The model focuses on characterizing the generation and transport of overspray mist. It extends previous work on conventional spray guns to include exposures generated by HVLP guns. Dimensional analysis and scale model wind-tunnel studies are employed using non-volatile oils, instead of paint, to produce empirical equations for estimating exposure to total mass. Results indicate that a dimensionless breathing zone concentration is a nonlinear function of the ratio of momentum flux of air from the spray gun to the momentum flux of air passing through the projected area of the worker's body. The orientation of the spraying operation within the booth is also very significant. The exposure model requires an estimate of the contaminant generation rate, which is approximated by a simple impactor model. The results represent an initial step in the construction of more realistic models capable of predicting exposure as a mathematical function of the governing parameters. PMID:10028895

  4. Detonation propagation through methane-air mixtures with fuel concentration gradients

    NASA Astrophysics Data System (ADS)

    Kessler, David; Gamezo, Vadim; Oran, Elaine

    2010-11-01

    The complex structure of a multidimensional detonation front consists of constantly changing, multiply intersecting incident shocks and Mach stems followed by growing and shrinking regions of reacted and unreacted gases. Because these flow structures change in time, the energy release in the shocked and compressed gases varies in space and time. Trajectories of triple points formed at shock intersections create cellular patterns whose size and structure are characteristic of the particular material and the background condition. In high-activation-energy fuel-air mixtures, such as methane in air, cellular patterns are relatively large, very irregular, and have complex and changing substructures. Here we use numerical simulations to study the behavior of detonations propagating through methane-air mixtures with a spatial gradient of fuel concentration. When the mixture stoichiometry varies from stoichiometric, the detonation propagation speed slows and sizes of cellular structures grow. In partially premixed systems with a nonuniform concentration of fuel -- a condition that can occur, for example, naturally in sealed underground coal mine tunnels -- both the propagation speed and the characteristic detonation cell size vary spatially.

  5. High Concentrations of Organic Contaminants in Air from Ship Breaking Activities in Chittagong, Bangladesh.

    PubMed

    Nøst, Therese H; Halse, Anne K; Randall, Scott; Borgen, Anders R; Schlabach, Martin; Paul, Alak; Rahman, Atiqur; Breivik, Knut

    2015-10-01

    The beaches on the coast of Chittagong in Bangladesh are one of the most intense ship breaking areas in the world. The aim of the study was to measure the concentrations of organic contaminants in the air in the city of Chittagong, including the surrounding ship breaking areas using passive air samplers (N = 25). The compounds detected in the highest amounts were the polycyclic aromatic hydrocarbons (PAHs) and short-chain chlorinated paraffins (SCCPs), whereas dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), and polychlorinated biphenyls (PCBs) were several orders of magnitude lower in comparison. PCBs, PAHs, and HCB were highest at sites near the ship breaking activities, whereas DDTs and SCCPs were higher in the urban areas. Ship breaking activities likely act as atmospheric emission sources of PCBs, PAHs, and HCB, thus adding to the international emphasis on responsible recycling of ships. Concentrations of PAHs, PCBs, DDTs, HCB, and SCCPs in ambient air in Chittagong are high in comparison to those found in similar studies performed in other parts of Asia. Estimated toxic equivalent quotients indicate elevated human health risks caused by inhalation of PAHs at most sites. PMID:26351879

  6. High Concentrations of Organic Contaminants in Air from Ship Breaking Activities in Chittagong, Bangladesh.

    PubMed

    Nøst, Therese H; Halse, Anne K; Randall, Scott; Borgen, Anders R; Schlabach, Martin; Paul, Alak; Rahman, Atiqur; Breivik, Knut

    2015-10-01

    The beaches on the coast of Chittagong in Bangladesh are one of the most intense ship breaking areas in the world. The aim of the study was to measure the concentrations of organic contaminants in the air in the city of Chittagong, including the surrounding ship breaking areas using passive air samplers (N = 25). The compounds detected in the highest amounts were the polycyclic aromatic hydrocarbons (PAHs) and short-chain chlorinated paraffins (SCCPs), whereas dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), and polychlorinated biphenyls (PCBs) were several orders of magnitude lower in comparison. PCBs, PAHs, and HCB were highest at sites near the ship breaking activities, whereas DDTs and SCCPs were higher in the urban areas. Ship breaking activities likely act as atmospheric emission sources of PCBs, PAHs, and HCB, thus adding to the international emphasis on responsible recycling of ships. Concentrations of PAHs, PCBs, DDTs, HCB, and SCCPs in ambient air in Chittagong are high in comparison to those found in similar studies performed in other parts of Asia. Estimated toxic equivalent quotients indicate elevated human health risks caused by inhalation of PAHs at most sites.

  7. Combining regression analysis and air quality modelling to predict benzene concentration levels

    NASA Astrophysics Data System (ADS)

    Vlachokostas, Ch.; Achillas, Ch.; Chourdakis, E.; Moussiopoulos, N.

    2011-05-01

    State of the art epidemiological research has found consistent associations between traffic-related air pollution and various outcomes, such as respiratory symptoms and premature mortality. However, many urban areas are characterised by the absence of the necessary monitoring infrastructure, especially for benzene (C 6H 6), which is a known human carcinogen. The use of environmental statistics combined with air quality modelling can be of vital importance in order to assess air quality levels of traffic-related pollutants in an urban area in the case where there are no available measurements. This paper aims at developing and presenting a reliable approach, in order to forecast C 6H 6 levels in urban environments, demonstrated for Thessaloniki, Greece. Multiple stepwise regression analysis is used and a strong statistical relationship is detected between C 6H 6 and CO. The adopted regression model is validated in order to depict its applicability and representativeness. The presented results demonstrate that the adopted approach is capable of capturing C 6H 6 concentration trends and should be considered as complementary to air quality monitoring.

  8. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  9. ELEVATED CO{sub 2} IN A PROTOTYPE FREE-AIR CO{sub 2} ENRICHMENT FACILITY AFFECTS PHOTOSYNTHETIC NITROGEN RELATIONS IN A MATURING PINE FOREST

    SciTech Connect

    ELLSWORTH,D.S.; LA ROCHE,J.; HENDREY,G.R.

    1998-03-01

    A maturing loblolly pine (Pinus taeda L.) forest was exposed to elevated CO{sub 2} in the natural environment in a perturbation study conducted over three seasons using the free-air CO{sub 2} enrichment (FACE) technique. At the time measurements were begun in this study, the pine canopy was comprised entirely of foliage which had developed under elevated CO{sub 2} conditions (atmospheric [CO{sub 2}] {approx} 550 {micro}mol mol{sup {minus}1}). Measurements of leaf photosynthetic responses to CO{sub 2} were taken to examine the effects of elevated CO{sub 2} on photosynthetic N nutrition in a pine canopy under elevated CO{sub 2}. Photosynthetic CO{sub 2} response curves (A-c{sub i} curves) were similar in FACE trees under elevated CO{sub 2} compared with counterpart trees in ambient plots for the first foliage cohort produced in the second season of CO{sub 2} exposure, with changes in curve form detected in the foliage cohorts subsequently produced under elevated CO{sub 2}. Differences in the functional relationship between carboxylation rate and N{sub a} suggest that for a given N{sub a} allocated among successive cohorts of foliage in the upper canopy, V{sub c max} was 17% lower in FACE versus Ambient trees. The authors also found that foliar Rubisco content per unit total protein derived from Western blot analysis was lower in late-season foliage in FACE foliage compared with ambient-grown foliage. The results illustrate a potentially important mode of physiological adjustment to growth conditions that may operate in forest canopies. Their findings suggest that mature loblolly pine trees growing in the field may have the capacity for shifts in intrinsic nitrogen utilization for photosynthesis under elevated CO{sub 2} that are not dependent on changes in leaf N. While carboxylation efficiency per unit N apparently decreased under elevated CO{sub 2}, photosynthetic rates in trees at elevated CO{sub 2} concentrations {approx} 550 pmol mol{sub {minus}1} are still

  10. Concentration, size, and density of total suspended particulates at the air exhaust of concentrated animal feeding operations.

    PubMed

    Yang, Xufei; Lee, Jongmin; Zhang, Yuanhui; Wang, Xinlei; Yang, Liangcheng

    2015-08-01

    Total suspended particulate (TSP) samples were seasonally collected at the air exhaust of 15 commercial concentrated animal feeding operations (CAFOs; including swine finishing, swine farrowing, swine gestation, laying hen, and tom turkey) in the U.S. Midwest. The measured TSP concentrations ranged from 0.38 ± 0.04 mg m⁻³ (swine gestation in summer) to 10.9 ± 3.9 mg m⁻³ (tom turkey in winter) and were significantly affected by animal species, housing facility type, feeder type (dry or wet), and season. The average particle size of collected TSP samples in terms of mass median equivalent spherical diameter ranged from 14.8 ± 0.5 µm (swine finishing in winter) to 30.5 ± 2.0 µm (tom turkey in summer) and showed a significant seasonal effect. This finding affirmed that particulate matter (PM) released from CAFOs contains a significant portion of large particles. The measured particle size distribution (PSD) and the density of deposited particles (on average 1.65 ± 0.13 g cm⁻³) were used to estimate the mass fractions of PM10 and PM2.5 (PM ≤ 10 and ≤ 2.5 μm, respectively) in the collected TSP. The results showed that the PM10 fractions ranged from 12.7 ± 5.1% (tom turkey) to 21.1 ± 3.2% (swine finishing), whereas the PM2.5 fractions ranged from 3.4 ± 1.9% (tom turkey) to 5.7 ± 3.2% (swine finishing) and were smaller than 9.0% at all visited CAFOs. This study applied a filter-based method for PSD measurement and deposited particles as a surrogate to estimate the TSP's particle density. The limitations, along with the assumptions adopted during the calculation of PM mass fractions, must be recognized when comparing the findings to other studies.

  11. Seasonal variation in vertical volatile compounds air concentrations within a remote hemiboreal mixed forest

    NASA Astrophysics Data System (ADS)

    Noe, S. M.; Hüve, K.; Niinemets, Ü.; Copolovici, L.

    2012-05-01

    The vertical distribution of ambient biogenic volatile organic compounds (BVOC) concentrations within a hemiboreal forest canopy was investigated over a period of one year. Variability in temporal and spatial isoprene concentrations, ranging from 0.1 to 7.5 μg m-3, can be mainly explained by biogenic emissions from deciduous trees. Monoterpene concentrations exceeded isoprene largely and ranged from 0.01 to 140 μg m-3 and during winter time anthropogenic contributions are likely. Variation in monoterpene concentrations were found to be largest right above the ground and the vertical profiles suggest a weak mixing leading to terpene accumulation in the lower canopy. Exceptionally high values were recorded during a heat wave in July 2010 with very high midday temperatures above 30 °C for several weeks. During summer months, monoterpene exceeded isoprene concentrations 6-fold and during winter 12-fold. During summer months, dominance of α-pinene in the lower and of limonene in the upper part of the canopy was observed, both accounting for up to 70% of the total monoterpene concentration. During wintertime, Δ3-carene was the dominant species, accounting for 60% of total monoterpene concentration in January. Possible biogenic monoterpene sources beside the foliage are the leaf litter, the soil and also resins exuding from stems. In comparison, the hemiboreal mixed forest canopy showed similar isoprene but higher monoterpene concentrations than the boreal forest and lower isoprene but substantially higher monoterpene concentrations than the temperate mixed forest canopies. These results have major implications for simulating air chemistry and secondary organic aerosol formation within and above hemiboreal forest canopies. Possible effects of in-cartridge oxidation reactions are discussed as our measurement technique did not include oxidant scavenging. A comparison between measurements with and without scavenging oxidants is presented.

  12. Surfactants in the sea-surface microlayer and sub-surface water at estuarine locations: Their concentration, distribution, enrichment, and relation to physicochemical characteristics.

    PubMed

    Huang, Yun-Jie; Brimblecombe, Peter; Lee, Chon-Lin; Latif, Mohd Talib

    2015-08-15

    Samples of sea-surface microlayer (SML) and sub-surface water (SSW) were collected from two areas-Kaohsiung City (Taiwan) and the southwest coast of Peninsular Malaysia to study the influence of SML on enrichment and distribution and to compare SML with the SSW. Anionic surfactants (MBAS) predominated in this study and were significantly higher in Kaohsiung than in Malaysia. Industrial areas in Kaohsiung were enriched with high loads of anthropogenic sources, accounted for higher surfactant amounts, and pose higher environmental disadvantages than in Malaysia, where pollutants were associated with agricultural activities. The dissolved organic carbon (DOC), MBAS, and cationic surfactant (DBAS) concentrations in the SML correlated to the SSW, reflecting exchanges between the SML and SSW in Kaohsiung. The relationships between surfactants and the physiochemical parameters indicated that DOC and saltwater dilution might affect the distributions of MBAS and DBAS in Kaohsiung. In Malaysia, DOC might be the important factor controlling DBAS. PMID:26093815

  13. Surfactants in the sea-surface microlayer and sub-surface water at estuarine locations: Their concentration, distribution, enrichment, and relation to physicochemical characteristics.

    PubMed

    Huang, Yun-Jie; Brimblecombe, Peter; Lee, Chon-Lin; Latif, Mohd Talib

    2015-08-15

    Samples of sea-surface microlayer (SML) and sub-surface water (SSW) were collected from two areas-Kaohsiung City (Taiwan) and the southwest coast of Peninsular Malaysia to study the influence of SML on enrichment and distribution and to compare SML with the SSW. Anionic surfactants (MBAS) predominated in this study and were significantly higher in Kaohsiung than in Malaysia. Industrial areas in Kaohsiung were enriched with high loads of anthropogenic sources, accounted for higher surfactant amounts, and pose higher environmental disadvantages than in Malaysia, where pollutants were associated with agricultural activities. The dissolved organic carbon (DOC), MBAS, and cationic surfactant (DBAS) concentrations in the SML correlated to the SSW, reflecting exchanges between the SML and SSW in Kaohsiung. The relationships between surfactants and the physiochemical parameters indicated that DOC and saltwater dilution might affect the distributions of MBAS and DBAS in Kaohsiung. In Malaysia, DOC might be the important factor controlling DBAS.

  14. Determination of lead, cations, and anions concentration in indoor and outdoor air at the primary schools in Kuala Lumpur.

    PubMed

    Awang, Normah; Jamaluddin, Farhana

    2014-01-01

    This study was carried out to determine the concentration of lead (Pb), anions, and cations at six primary schools located around Kuala Lumpur. Low volume sampler (MiniVol PM10) was used to collect the suspended particulates in indoor and outdoor air. Results showed that the concentration of Pb in indoor air was in the range of 5.18 ± 1.08 μg/g-7.01 ± 0.08 μg/g. All the concentrations of Pb in indoor air were higher than in outdoor air at all sampling stations. The concentrations of cations and anions were higher in outdoor air than in indoor air. The concentration of Ca(2+) (39.51 ± 5.01 mg/g-65.13 ± 9.42 mg/g) was the highest because the cation existed naturally in soil dusts, while the concentrations of NO3 (-) and SO4 (2-) were higher in outdoor air because there were more sources of exposure for anions in outdoor air, such as highly congested traffic and motor vehicles emissions. In comparison, the concentration of NO3 (-) (29.72 ± 0.31 μg/g-32.00 ± 0.75 μg/g) was slightly higher than SO4 (2-). The concentrations of most of the parameters in this study, such as Mg(2+), Ca(2+), NO3 (-), SO4 (2-), and Pb(2+), were higher in outdoor air than in indoor air at all sampling stations.

  15. Modeling VOC emissions and air concentrations from the Exxon Valdez oil spill

    SciTech Connect

    Hanna, S.R. ); Drivas, P.J. )

    1993-03-01

    During the two-week period following the Exxon Valdez oil spill in March 1989 in Prince William Sound, Alaska, toxic volatile organic compounds (VOCs) evaporated from the surface of the oil spill and were transported and dispersed throughout the region. To estimate the air concentrations of these VOCs, emissions and dispersion modeling was conducted for each hour during the first two weeks of the spill. A multicomponent evaporative emissions model was developed and applied to the oil spill; the model considered the evaporation of 15 specific compounds, including benzene and toluene. Both mass transfer from the surface of the spill and diffusion through the oil layer were considered in the emissions model. Maximum emissions of toluene were calculated to equal about 20,000 kg/hr, or about 5 g/m[sup 2] hr, at a time of eight hours after the initial oil spill. Meteorological data were acquired from sources and used to estimate hourly-averaged wind velocity over the spill. Air concentrations of specific components were calculated using the ATDL area source diffusion model and the Offshore and Coastal Dispersion (OCD) model. Maximum hourly-averaged concentrations were predicted not to exceed 10 ppmv for any compound. 24 refs., 6 figs., 4 tabs.

  16. Air quality modelling : effects of emission reductions on concentrations of particulate matter

    NASA Astrophysics Data System (ADS)

    Girault, L.; Roustan, Y.; Seigneur, C.

    2012-04-01

    Atmospheric particulate matter (PM) has adverse effects on human health. PM acts primarily on respiratory and cardiovascular (due to their small size they can penetrate deep into the lungs), but they are also known effects on the skin. In France, the "Particulate Plan" - developed as part of the second National Environmental Health Plan - aims to reduce by 30% fine PM (noted PM2.5because these particles have an aerodynamic diameter of 2.5 micrometers or less) by 2015. A recent study by Airparif (the organization in charge of monitoring air quality in the Paris region, the Île-de-France) and LSCE (Laboratory of climate and the environmental science, France) has allowed, through a large measurement campaign conducted between 2009 and 2011, to quantify the proportion of PM produced in Île-de-France and those transported from the surrounding areas. The study by numerical modelling of air pollution presented here complements these results by investigating future emission scenarios. The CEREA develops and uses an air quality model which simulates the concentrations of pollutants from an emission inventory, meteorological data and boundary conditions of the area studied. After an evaluation of simulation results for the year 2005, the model is used to assess the effects of various scenarios of reductions in NOx and NH3 emissions on the concentrations of PM2.5in Île-de-France. The effects of the controls on the local pollution and the long-range pollution are considered separately. For each emitted species, three scenarios of emission reductions are identified: an emission reduction at the local level (Île-de-France), a reduction at the regional scale (France) and a reduction at the continental scale (across Europe). In each case, a 15% reduction is applied. The comparison of the results allows us to assess the respective contributions of local emissions and long-range transport to PM2.5 concentrations. For instance, the reduction of NOx emissions in Europe leads to a

  17. Contribution of ship emissions to the concentration and deposition of air pollutants in Europe

    NASA Astrophysics Data System (ADS)

    Aksoyoglu, Sebnem; Baltensperger, Urs; Prévôt, André S. H.

    2016-02-01

    Emissions from the marine transport sector are one of the least-regulated anthropogenic emission sources and contribute significantly to air pollution. Although strict limits were introduced recently for the maximum sulfur content in marine fuels in the SECAs (sulfur emission control areas) and in EU ports, sulfur emissions outside the SECAs and emissions of other components in all European maritime areas have continued to increase in the last two decades. We have used the air quality model CAMx (Comprehensive Air Quality Model with Extensions) with and without ship emissions for the year 2006 to determine the effects of international shipping on the annual as well as seasonal concentrations of ozone, primary and secondary components of PM2.5, and the dry and wet deposition of nitrogen and sulfur compounds in Europe. The largest changes in pollutant concentrations due to ship emissions were predicted for summer. Concentrations of particulate sulfate increased due to ship emissions in the Mediterranean (up to 60 %), the English Channel and the North Sea (30-35 %), while increases in particulate nitrate levels were found especially in the north, around the Benelux area (20 %), where there were high NH3 land-based emissions. Our model results showed that not only are the atmospheric concentrations of pollutants affected by ship emissions, but also depositions of nitrogen and sulfur compounds increase significantly along the shipping routes. NOx emissions from the ships, especially in the English Channel and the North Sea, cause a decrease in the dry deposition of reduced nitrogen at source regions by moving it from the gas phase to the particle phase which then contributes to an increase in the wet deposition at coastal areas with higher precipitation. In the western Mediterranean region, on the other hand, model results show an increase in the deposition of oxidized nitrogen (mostly HNO3) due to the ship traffic. Dry deposition of SO2 seems to be significant along

  18. Extraordinary acoustic transmission through annuluses in air and its applications in acoustic beam splitter and concentrator.

    PubMed

    Ge, Yong; Sun, Hong-Xiang; Liu, Shu-Sen; Yuan, Shou-Qi; Xia, Jian-Ping; Guan, Yi-Jun; Zhang, Shu-Yi

    2016-08-01

    We report an extraordinary acoustic transmission through two layer annuluses made of metal cylinders in air both numerically and experimentally. The effect arises from the enhancement and reconstruction of the incident source induced by different Mie-resonance modes of the annuluses. The proposed system takes advantages of the consistency in the waveform between the input and output waves, the high amplitude amplification of output waves, and the easy adjustment of structure. More interestingly, we investigate the applications of the extraordinary acoustic transmission in the acoustic beam splitter and acoustic concentrator. Our finding should have an impact on ultrasonic applications. PMID:27587144

  19. Extraordinary acoustic transmission through annuluses in air and its applications in acoustic beam splitter and concentrator

    NASA Astrophysics Data System (ADS)

    Ge, Yong; Sun, Hong-xiang; Liu, Shu-sen; Yuan, Shou-qi; Xia, Jian-ping; Guan, Yi-jun; Zhang, Shu-yi

    2016-08-01

    We report an extraordinary acoustic transmission through two layer annuluses made of metal cylinders in air both numerically and experimentally. The effect arises from the enhancement and reconstruction of the incident source induced by different Mie-resonance modes of the annuluses. The proposed system takes advantages of the consistency in the waveform between the input and output waves, the high amplitude amplification of output waves, and the easy adjustment of structure. More interestingly, we investigate the applications of the extraordinary acoustic transmission in the acoustic beam splitter and acoustic concentrator. Our finding should have an impact on ultrasonic applications.

  20. Use of dust fall filters as passive samplers for metal concentrations in air for communities near contaminated mine tailings

    PubMed Central

    Beamer, P.I.; Sugeng, A. J.; Kelly, M.D.; Lothrop, N.; Klimecki, W.; Wilkinson, S.T.; Loh, M.

    2014-01-01

    Mine tailings are a source of metal exposures in many rural communities. Multiple air samples are necessary to assess the extent of exposures and factors contributing to these exposures. However, air sampling equipment is costly and requires trained personnel to obtain measurements, limiting the number of samples that can be collected. Simple, low-cost methods are needed to allow for increased sample collection. The objective of our study was to assess if dust fall filters can serve as passive air samplers and be used to characterize potential exposures in a community near contaminated mine tailings. We placed filters in cylinders, concurrently with active indoor air samplers, in 10 occupied homes. We calculated an estimated flow rate by dividing the mass on each dust fall filter by the bulk air concentration and the sampling duration. The mean estimated flow rate for dust fall filters was significantly different during sampling periods with precipitation. The estimated flow rate was used to estimate metal concentration in the air of these homes, as well as in 31 additional homes in another rural community impacted by contaminated mine tailings. The estimated air concentrations had a significant linear association with the measured air concentrations for beryllium, manganese and arsenic (p<0.05), whose primary source in indoor air is resuspended soil from outdoors. In the second rural community, our estimated metal concentrations in air were comparable to active air sampling measurements taken previously. This passive air sampler is a simple low-cost method to assess potential exposures near contaminated mining sites. PMID:24469149

  1. GC/MS method for determining carbon isotope enrichment and concentration of underivatized short-chain fatty acids by direct aqueous solution injection of biogas digester samples.

    PubMed

    Mulat, Daniel Girma; Feilberg, Anders

    2015-10-01

    In anaerobic digestion of organic matter, several metabolic pathways are involved during the simultaneous production and consumption of short-chain fatty acids (SCFA) in general and acetate in particular. Understanding the role of each pathway requires both the determination of the concentration and isotope enrichment of intermediates in conjunction with isotope labeled substrates. The objective of this study was to establish a rapid and simple GC/MS method for determining the isotope enrichment of acetate and concentration of underivatized short-chain fatty acids (SCFA) in biogas digester samples by direct liquid injection of acidified aqueous samples. Sample preparation involves only acidification, centrifugation and filtration of the aqueous solution followed by direct injection of the aqueous supernatant solution onto a polar column. With the sample preparation and GC/MS conditions employed, well-resolved and sharp peaks of underivatized SCFA were obtained in a reasonably short time. Good recovery (96.6-102.3%) as well as low detection (4-7 µmol/L) and quantification limits (14-22 µmol/L) were obtained for all the 6 SCFA studied. Good linearity was achieved for both concentration and isotope enrichment measurement with regression coefficients higher than 0.9978 and 0.9996, respectively. The method has a good intra- and inter-day precision with a relative standard deviation (RSD) below 6% for determining the tracer-to-tracee ratio (TTR) of both [2-(13)C]acetate and [U-(13)C]acetate. It has also a good intra- and inter-day precision with a RSD below 6% and 5% for determining the concentration of standard solution and biogas digester samples, respectively. Acidification of biogas digester samples with oxalic acid provided the low pH required for the protonation of SCFA and thus, allows the extraction of SCFA from the complex sample matrix. Moreover, oxalic acid was the source of formic acid which was produced in the injector set at high temperature. The produced

  2. Features of a micro-gas chromatograph equipped with enrichment device and microchip plasma emission detection (muPED) for air monitoring.

    PubMed

    Tienpont, Bart; David, Frank; Witdouck, Wim; Vermeersch, Dries; Stoeri, Herbert; Sandra, Pat

    2008-11-01

    A field portable gas chromatograph (GC) was constructed allowing the enrichment of organic solutes from air samples on a miniaturized chemical trap and the subsequent gas chromatographic analysis on a resistively heated capillary column. The heart of the system is an integrated chip-based plasma emission detector (muPED). As a non-selective detector, the sensitivity is similar to that of a flame ionization detector (FID). The detector shows good selectivity for phosphorus, sulfur and chlorine-containing compounds with relative selectivities of ca. 5 x 10(5) gP gC(-1), 50 gS gC(-1) and 10(2) gCl gC(-1). The lifetime of the plasma chip under air monitoring conditions exceeded 3000 analyses. PMID:18941680

  3. Mixing layer height measurements determines influence of meteorology on air pollutant concentrations in urban area

    NASA Astrophysics Data System (ADS)

    Schäfer, Klaus; Blumenstock, Thomas; Bonn, Boris; Gerwig, Holger; Hase, Frank; Münkel, Christoph; Nothard, Rainer; von Schneidemesser, Erika

    2015-10-01

    Mixing layer height (MLH) is a key parameter to determine the influence of meteorological parameters upon air pollutants such as trace gas species and particulate concentrations near the surface. Meteorology, and MLH as a key parameter, affect the budget of emission source strengths, deposition, and accumulation. However, greater possibilities for the application of MLH data have been identified in recent years. Here, the results of measurements in Berlin in 2014 are shown and discussed. The concentrations of NO, NO2, O3, CO, PM1, PM2.5, PM10 and about 70 volatile organic compounds (anthropogenic and biogenic of origin) as well as particle size distributions and contributions of SOA and soot species to PM were measured at the urban background station of the Berlin air quality network (BLUME) in Nansenstr./Framstr., Berlin-Neukölln. A Vaisala ceilometer CL51, which is a commercial mini-lidar system, was applied at that site to detect the layers of the lower atmosphere in real time. Special software for these ceilometers with MATLAB provided routine retrievals of MLH from vertical profiles of laser backscatter data. Five portable Bruker EM27/SUN FTIR spectrometers were set up around Berlin to detect column averaged abundances of CO2 and CH4 by solar absorption spectrometry. Correlation analyses were used to show the coupling of temporal variations of trace gas compounds and PM with MLH. Significant influences of MLH upon NO, NO2, PM10, PM2.5, PM1 and toluene (marker for traffic emissions) concentrations as well as particle number concentrations in the size modes 70 - 100 nm, 100 - 200 nm and 200 - 500 nm on the basis of averaged diurnal courses were found. Further, MLH was taken as important auxiliary information about the development of the boundary layer during each day of observations, which was required for the proper estimation of CO2 and CH4 source strengths from Berlin on the basis of atmospheric column density measurements.

  4. A CO2 concentration gradient facility for testing CO2 enrichment and soil effects on grassland ecosystem function

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continuing increases in atmospheric CO2 concentrations mandate techniques for examining impacts on terrestrial ecosystems. Most experiments examine only two or a few levels of CO2 concentration and a single soil type, but if CO2 can be varied as a gradient from subambient to superambient concentra...

  5. Effect of omega-3 and omega-6 polyunsaturated fatty acid enriched diet on plasma IGF-1 and testosterone concentration, puberty and semen quality in male buffalo.

    PubMed

    Tran, L V; Malla, B A; Sharma, A N; Kumar, Sachin; Tyagi, Nitin; Tyagi, A K

    2016-10-01

    The objective of the present study was to evaluate the effect of omega-3 and omega-6 PUFA enriched diet on plasma IGF-1 and testosterone concentrations, puberty, sperm fatty acid profile and semen quality in male buffalo. Eighteen male buffalo calves were distributed randomly in three different groups and fed concentrate mixture along with green fodder and wheat straw in 50:40:10 ratios as per requirements. Basis ration of animals in group I was supplemented with 4% of prilled fat (PFA), while in group II and group III were added 4.67% of Calcium salt from Soybean (CaSFA) and Linseed oil (CaLFA), respectively. Male buffalo fed omega-3 PUFA high diet significantly increased concentrations of IGF-1 and testosterone in plasma as compared to two other diets (p<0.05). The age of puberty and scrotal circumference significantly increased by dietary fat effect (p<0.05) of which n-3 PUFA enriched diet (CaLFA) had the largest influence as compared to other diets (PFA and CaSFA). Feeding of n-3 PUFA rich diet significantly increased the DHA (C22:6n-3) content in sperm (p<0.05), which contributed to increased fluidity of plasma membrane, elevated quality of sperm (motility, viability) and in vitro fertility (plasma membrane integrity, acrosome integrity) in both fresh and post-thawing semen. These findings indicate that feeding of n-3 PUFA enriched diet increased IGF-1 and testosterone secretion, reduced pubertal age and improved both fresh and post-thawing semen quality in male buffalo.

  6. Effect of omega-3 and omega-6 polyunsaturated fatty acid enriched diet on plasma IGF-1 and testosterone concentration, puberty and semen quality in male buffalo.

    PubMed

    Tran, L V; Malla, B A; Sharma, A N; Kumar, Sachin; Tyagi, Nitin; Tyagi, A K

    2016-10-01

    The objective of the present study was to evaluate the effect of omega-3 and omega-6 PUFA enriched diet on plasma IGF-1 and testosterone concentrations, puberty, sperm fatty acid profile and semen quality in male buffalo. Eighteen male buffalo calves were distributed randomly in three different groups and fed concentrate mixture along with green fodder and wheat straw in 50:40:10 ratios as per requirements. Basis ration of animals in group I was supplemented with 4% of prilled fat (PFA), while in group II and group III were added 4.67% of Calcium salt from Soybean (CaSFA) and Linseed oil (CaLFA), respectively. Male buffalo fed omega-3 PUFA high diet significantly increased concentrations of IGF-1 and testosterone in plasma as compared to two other diets (p<0.05). The age of puberty and scrotal circumference significantly increased by dietary fat effect (p<0.05) of which n-3 PUFA enriched diet (CaLFA) had the largest influence as compared to other diets (PFA and CaSFA). Feeding of n-3 PUFA rich diet significantly increased the DHA (C22:6n-3) content in sperm (p<0.05), which contributed to increased fluidity of plasma membrane, elevated quality of sperm (motility, viability) and in vitro fertility (plasma membrane integrity, acrosome integrity) in both fresh and post-thawing semen. These findings indicate that feeding of n-3 PUFA enriched diet increased IGF-1 and testosterone secretion, reduced pubertal age and improved both fresh and post-thawing semen quality in male buffalo. PMID:27596261

  7. Final report on the project entitled: Highly Preheated Combustion Air System with/without Oxygen Enrichment for Metal Processing Furnaces

    SciTech Connect

    Arvind Atreya

    2007-02-16

    This work develops and demonstrates a laboratory-scale high temperature natural gas furnace that can operate with/without oxygen enrichment to significantly improve energy efficiency and reduce emissions. The laboratory-scale is 5ft in diameter & 8ft tall. This furnace was constructed and tested. This report demonstrates the efficiency and pollutant prevention capabilities of this test furnace. The project also developed optical detection technology to control the furnace output.

  8. Development of particle induced gamma-ray emission methods for nondestructive determination of isotopic composition of boron and its total concentration in natural and enriched samples.

    PubMed

    Chhillar, Sumit; Acharya, Raghunath; Sodaye, Suparna; Pujari, Pradeep K

    2014-11-18

    We report simple particle induced gamma-ray emission (PIGE) methods using a 4 MeV proton beam for simultaneous and nondestructive determination of the isotopic composition of boron ((10)B/(11)B atom ratio) and total boron concentrations in various solid samples with natural isotopic composition and enriched with (10)B. It involves measurement of prompt gamma-rays at 429, 718, and 2125 keV from (10)B(p,αγ)(7)Be, (10)B(p, p'γ)(10)B, and (11)B(p, p'γ)(11)B reactions, respectively. The isotopic composition of boron in natural and enriched samples was determined by comparing peak area ratios corresponding to (10)B and (11)B of samples to natural boric acid standard. An in situ current normalized PIGE method, using F or Al, was standardized for total B concentration determination. The methods were validated by analyzing stoichiometric boron compounds and applied to samples such as boron carbide, boric acid, carborane, and borosilicate glass. Isotopic compositions of boron in the range of 0.247-2.0 corresponding to (10)B in the range of 19.8-67.0 atom % and total B concentrations in the range of 5-78 wt % were determined. It has been demonstrated that PIGE offers a simple and alternate method for total boron as well as isotopic composition determination in boron based solid samples, including neutron absorbers that are important in nuclear technology.

  9. Soil Surface Carbon Dioxide Fluxes and Carbon Dioxide Concentrations in Soil Air

    NASA Astrophysics Data System (ADS)

    Arkebauer, T. J.; Billesbach, D.

    2006-12-01

    We have been monitoring soil surface CO2 fluxes at three AmeriFlux sites in eastern Nebraska for several years. Recently, we have installed soil CO2 sensors at the rainfed soybean site in order to obtain profiles of CO2 concentrations in soil air (to 0.8 m depth). Supporting data include profiles of soil water content and soil temperature, aboveground biomass, leaf area index and precipitation. Soil surface fluxes had been rather small for much of the 2006 growing season (e.g., midday values of about 5 umol/m2/s) due, in large part, to the very dry conditions in eastern Nebraska and the consequent low soil water contents. However, copious rainfall in August raised soil water contents to field capacity throughout the profile. Soil air CO2 concentrations during this period also increased and reached peaks near 10% (at 0.4 and 0.8 m depth). Through analyses of relationships between surface CO2 flux and profiles of soil parameters we seek to identify biophysical factors responsible for controlling surface fluxes as well as to begin to quantify sources and sinks of CO2 within the soil profile (e.g., plant-related production of CO2 due to root exudation and respiration). The influence of precipitation events on CO2 profiles and fluxes is of particular interest.

  10. Portable Cathode-Air Vapor-Feed Electrochemical Medical Oxygen Concentrator (OC)

    NASA Technical Reports Server (NTRS)

    Balasubramanian, Ashwin

    2015-01-01

    Missions on the International Space Station and future space exploration will present significant challenges to crew health care capabilities, particularly in the efficient utilization of onboard oxygen resources. Exploration vehicles will require lightweight, compact, and portable oxygen concentrators that can provide medical-grade oxygen from the ambient cabin air. Current pressure-swing adsorption OCs are heavy and bulky, require significant start-up periods, operate in narrow temperature ranges, and require a liquid water feed. Lynntech, Inc., has developed an electrochemical OC that operates with a cathode-air vapor feed, eliminating the need for a bulky onboard water supply. Lynntech's OC is smaller and lighter than conventional pressure-swing OCs, is capable of instant start-up, and operates over a temperature range of 5-80 C. Accomplished through a unique nanocomposite proton exchange membrane and catalyst technology, the unit delivers 4 standard liters per minute of humidified oxygen at 60 percent concentration. The technology enables both ambient-pressure operating devices for portable applications and pressurized (up to 3,600 psi) OC devices for stationary applications.

  11. Distinct patterns in the diurnal and seasonal variability in four components of soil respiration in a temperate forest under free-air CO2 enrichment

    NASA Astrophysics Data System (ADS)

    Taneva, L.; Gonzalez-Meler, M. A.

    2011-10-01

    Soil respiration (RS) is a major flux in the global carbon (C) cycle. Responses of RS to changing environmental conditions may exert a strong control on the residence time of C in terrestrial ecosystems and in turn influence the atmospheric concentration of greenhouse gases. Soil respiration consists of several components oxidizing soil C from different pools, age and chemistry. The mechanisms underlying the temporal variability of RS components are poorly understood. In this study, we used the long-term whole-ecosystem 13C tracer at the Duke Forest Free Air CO2 Enrichment site to separate forest RS into its autotrophic (RR) and heterotrophic components (RH). The contribution of RH to RS was further partitioned into litter decomposition (RL), and decomposition of soil organic matter (RSOM) of two age classes - up to 8 yr old and SOM older than 8 yr. Soil respiration was generally dominated by RSOM during the growing season (44% of daytime RS), especially at night. The contribution of heterotrophic respiration (RSOM and RL) to RS was not constant, indicating that the seasonal variability in RR alone cannot explain seasonal variation in RS. Although there was no diurnal variability in RS, there were significant compensatory differences in the contribution of individual RS components to daytime and nighttime rates. The average contribution of RSOM to RS was greater at night (54%) than during the day (44%). The average contribution of RR to total RS was ~30% during the day and ~34% during the night. In contrast, RL constituted 26% of RS during the day and only 12% at night. About 95% of the decomposition of soil C older than 8 yr (Rpre-tr) originated from RSOM and showed more pronounced and consistent diurnal variability than any other RS component; nighttime rates were on average 29% higher than daytime rates. In contrast, the decomposition of more recent, post-treatment C (Rpre-tr) did not vary diurnally. None of the diurnal variations in components of RH could be

  12. Long term analysis of the biomass content in the feed of a waste-to-energy plant with oxygen-enriched combustion air.

    PubMed

    Fellner, Johann; Cencic, Oliver; Zellinger, Günter; Rechberger, Helmut

    2011-10-01

    Thermal utilization of municipal solid waste and commercial wastes has become of increasing importance in European waste management. As waste materials are generally composed of fossil and biogenic materials, a part of the energy generated can be considered as renewable and is thus subsidized in some European countries. Analogously, CO(2) emissions of waste incinerators are only partly accounted for in greenhouse gas inventories. A novel approach for determining these fractions is the so-called balance method. In the present study, the implementation of the balance method on a waste-to-energy plant using oxygen-enriched combustion air was investigated. The findings of the 4-year application indicate on the one hand the general applicability and robustness of the method, and on the other hand the importance of reliable monitoring data. In particular, measured volume flows of the flue gas and the oxygen-enriched combustion air as well as corresponding O(2) and CO(2) contents should regularly be validated. The fraction of renewable (biogenic) energy generated throughout the investigated period amounted to between 27 and 66% for weekly averages, thereby denoting the variation in waste composition over time. The average emission factor of the plant was approximately 45 g CO(2) MJ(-1) energy input or 450 g CO(2) kg(-1) waste incinerated. The maximum error of the final result was about 16% (relative error), which was well above the error (<8%) of the balance method for plants with conventional oxygen supply.

  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. LINKING AIR TOXIC CONCENTRATIONS FROM CMAQ TO THE HAPEM5 EXPOSURE MODEL AT NEIGHORHOOD SCALES FOR THE PHILADELPHIA AREA

    EPA Science Inventory

    This paper provides a preliminary demonstration of the EPA neighborhood scale modeling paradigm for air toxics by linking concentration from the Community Multi-scale Air Quality (CMAQ) modeling system to the fifth version of the Hazardous Pollutant Exposure Model (HAPEM5). For ...

  15. Effect of central ventilation and air conditioner system on the concentration and health risk from airborne polycyclic aromatic hydrocarbons.

    PubMed

    Lv, Jinze; Zhu, Lizhong

    2013-03-01

    Central ventilation and air conditioner systems are widely utilized nowadays in public places for air exchange and temperature control, which significantly influences the transfer of pollutants between indoors and outdoors. To study the effect of central ventilation and air conditioner systems on the concentration and health risk from airborne pollutants, a spatial and temporal survey was carried out using polycyclic aromatic hydrocarbons (PAHs) as agent pollutants. During the period when the central ventilation system operated without air conditioning (AC-off period), concentrations of 2-4 ring PAHs in the model supermarket were dominated by outdoor levels, due to the good linearity between indoor air and outdoor air (r(p) > 0.769, p < 0.05), and the slopes (1.2-4.54) indicated that ventilating like the model supermarket increased the potential health risks from low molecular weight PAHs. During the period when the central ventilation and air conditioner systems were working simultaneously (AC-on period), although the total levels of PAHs were increased, the concentrations and percentage of the particulate PAHs indoors declined significantly. The BaP equivalency (BaPeq) concentration indicated that utilization of air conditioning reduced the health risks from PAHs in the model supermarket. PMID:23923426

  16. Influence of eutrophication on air-water exchange, vertical fluxes, and phytoplankton concentrations of persistent organic pollutants

    SciTech Connect

    Dachs, J.; Eisenreich, S.J.; Hoff, R.M.

    2000-03-15

    The influence of eutrophication on the biogeochemical cycles of persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) is largely unknown. In this paper, the application of a dynamic air-water-phytoplankton exchange model to Lake Ontario is used as a framework to study the influence of eutrophication on air-water exchange, vertical fluxes, and phytoplankton concentrations of POPs. The results of these simulations demonstrate that air-water exchange controls phytoplankton concentrations in remote aquatic environments with little influence from land-based sources of pollutants and supports levels in even historically contaminated systems. Furthermore, eutrophication or high biomass leads to a disequilibrium between the gas and dissolved phase, enhanced air-water exchange, and vertical sinking fluxes of PCBs. Increasing biomass also depletes the water concentrations leading to lower than equilibrium PCB concentrations in phytoplankton. Implications to future trends in PCB pollution in Lake Ontario are also discussed.

  17. Concentrated ambient air particles induce vasoconstriction of small pulmonary arteries in rats.

    PubMed Central

    Batalha, Joao R F; Saldiva, Paulo H N; Clarke, Robert W; Coull, Brent A; Stearns, Rebecca C; Lawrence, Joy; Murthy, G G Krishna; Koutrakis, Petros; Godleski, John J

    2002-01-01

    The objective of this study was to determine whether short-term exposures to concentrated ambient particles (CAPs) alter the morphology of small pulmonary arteries in normal rats and rats with chronic bronchitis (CB). Sprague-Dawley male rats were exposed to CAPs, using the Harvard Ambient Particle Concentrator, or to particle-free air (sham) under identical conditions during 3 consecutive days (5 hr/day) in six experimental sets. CB was induced by exposure to 276 +/- 9 ppm of sulfur dioxide (5 hr/day, 5 days/week, 6 weeks). Physicochemical characterization of CAPs included measurements of particle mass, size distribution, and composition. Rats were sacrificed 24 hr after the last CAPs exposure. Histologic slides were prepared from random sections of lung lobes and coded for blinded analysis. The lumen/wall area (L/W) ratio was determined morphometrically on transverse sections of small pulmonary arteries. When all animal data (normal and CB) were analyzed together, the L/W ratios decreased as concentrations of fine particle mass, silicon, lead, sulfate, elemental carbon, and organic carbon increased. In separate univariate analyses of animal data, the association for sulfate was significant only in normal rats, whereas silicon was significantly associated in both CB and normal rats. In multivariate analyses including all particle factors, the association with silicon remained significant. Our results indicate that short-term CAPs exposures (median, 182.75 micro g/m3; range, 73.50-733.00 micro g/m3) can induce vasoconstriction of small pulmonary arteries in normal and CB rats. This effect was correlated with specific particle components and suggests that the pulmonary vasculature might be an important target for ambient air particle toxicity. PMID:12460797

  18. Diagnostic significance of nitric oxide concentrations in exhaled air from the airways in allergic rhinitis patients

    PubMed Central

    Krzych-Fałta, Edyta; Samoliński, Bolesław K; Zalewska, Marta

    2016-01-01

    Introduction The effect of nitric oxide (NO) on the human body is very important due its physiological regulation of the following functions of airways: modulation of ciliary movement and maintenance of sterility in sinuses. Aim To evaluate the diagnostic significance of NO concentrations in exhaled air from the upper and lower airways in patients diagnosed with allergic rhinitis (AR). Material and methods The subjects included in the study were a group of 30 people diagnosed with sensitivity to environmental allergens and a control group consisting of 30 healthy subjects. The measurement of NO in the air exhaled from the lower and upper airways was performed using an on-line method by means of Restricted Exhaled Breath (REB), as well as using the measurement procedure (chemiluminescence) set out in the guidelines prepared in 2005 by the American Thoracic Society and the European Respiratory Society. Results In the late phase of the allergic reaction, higher values of the level of exhaled NO concentration from the lower airways were observed in the groups of subjects up to the threshold values of 25.17 ppb in the group of subjects with year-round allergic rhinitis and 21.78 ppb in the group with diagnosed seasonal allergic rhinitis. The difference in the concentration of NO exhaled from the lungs between the test group and the control group in the 4th h of the test was statistically significant (p = 0.045). Conclusions Exhaled NO should be considered as a marker of airway inflammation. It plays an important role in the differential diagnosis of allergy. PMID:27279816

  19. Analysis of radionuclide concentration in air released through the stack of a radiopharmaceutical production facility based on a medical cyclotron

    NASA Astrophysics Data System (ADS)

    Giardina, M.; Tomarchio, E.; Greco, D.

    2015-11-01

    Positron emitting radionuclides are increasingly used in medical diagnostics and the number of radiopharmaceutical production facilities have been estimated to be growing worldwide. During the process of production and/or patient administration of radiopharmaceuticals, an amount of these radionuclides might become airborne and escape into the environment. Therefore, the analysis of radionuclide concentration in the air released to the stack is a very important issue to evaluate the dose to the population living around the plant. To this end, sampling and measurement of radionuclide concentration in air released through the stack of a Nuclear Medicine Center (NMC), provided with a cyclotron for radiopharmaceuticals production, must be routinely carried out with an automatic measurement system. In this work is presented the air monitoring system realized at "San Gaetano" NMC at Bagheria (Italy) besides the analysis of the recorded stack relesead air concentration data. Sampling of air was carried out continuously and gamma-ray spectrometric measurement are made on-line and for a short time by using a shielded Marinelli beaker filled with sampled air and a gamma detector. The use of this system allows to have 1440 values of air concentration per day from 2002, year of the start of operation with the cyclotron. Therefore, the concentration values are very many and an analysis software is needed to determine the dose to the population. A comparison with the results of a simulation code based on a Gaussian Plume air dispersion modelling allow us to confirm the no-radiological significance of the stack effluent releases in terms of dose to population and to evaluate possible improvements in the plant devices to reduce the air concentration at stack.

  20. MTBE concentrations in ambient air in the vicinity of service stations

    NASA Astrophysics Data System (ADS)

    Vainiotalo, Sinikka; Peltonen, Yrjö; Pfäffli, Pirkko

    Ambient air concentrations of methyl tertiary-butyl ether (MTBE) were monitored in the vicinity of two self-service stations in May-June and October, 1995. These stations (one urban and one roadside) were located in southwestern Finland and were equipped with "stage I" vapour recovery systems. All the gasoline blends dispensed during the study (95, 98 and 99 RON) contained 11% MTBE. The measurements were carried out 24 h day -1 at stationary sampling points located at the four main compass points on the service station perimeter (about 50 m from the centre of the forecourt). The air samples were collected in charcoal tubes and analysed in laboratory by gas chromatography using mass-selective detection. The concentrations in individual samples ranged from 0.5 to 121 μg m -3, and the highest daily concentrations were usually obtained at the downwind sampling points. The arithmetic mean concentrations for each of the four-day sampling periods were: 7.5 μg m -3 (station 1/May-June), 4.1 μg/m 3 (station 1/October), 12.4 μg m -3 (station 2/June) and 14.1 μg m -3 (station 2/October). The mean concentrations measured in the centre of the pump island (only daytime sampling) ranged from 247 to 1347 μg m -3. The levels of MTBE are station-specific and dependent on many factors, such as volumes of gasolines sold, wind speed, exhaust emissions from passing traffic, and deliveries of gasoline to the station. The mean wind speeds were between 0.7 and 1.5 m s -1, and the temperatures were above 22°C in summer and about 10°C in October. The volume of gasoline sold at the urban service station, station 2, was twice that at the roadside service station, station 1. There was one road with high traffic density adjacent to station 1 and two such roads at station 2. Gasoline was delivered twice to station 1 and 3 times to station 2 during the study.

  1. The concentration-response relation between air pollution and daily deaths.

    PubMed Central

    Schwartz, J; Ballester, F; Saez, M; Pérez-Hoyos, S; Bellido, J; Cambra, K; Arribas, F; Cañada, A; Pérez-Boillos, M J; Sunyer, J

    2001-01-01

    Studies on three continents have reported associations between various measures of airborne particles and daily deaths. Sulfur dioxide has also been associated with daily deaths, particularly in Europe. Questions remain about the shape of those associations, particularly whether there are thresholds at low levels. We examined the association of daily concentrations of black smoke and SO(2) with daily deaths in eight Spanish cities (Barcelona, Bilbao, Castellón, Gijón, Oviedo, Valencia, Vitoria, and Zaragoza) with different climates and different environmental and social characteristics. We used nonparametric smoothing to estimate the shape of the concentration-response curve in each city and combined those results using a metasmoothing technique developed by Schwartz and Zanobetti. We extended their method to incorporate random variance components. Black smoke had a nearly linear association with daily deaths, with no evidence of a threshold. A 10 microg/m(3) increase in black smoke was associated with a 0.88% increase in daily deaths (95% confidence interval, 0.56%-1.20%). SO(2) had a less plausible association: Daily deaths increased at very low concentrations, but leveled off and then decreased at higher concentrations. These findings held in both one- and two-pollutant models and held whether we optimized our weather and seasonal model in each city or used the same smoothing parameters in each city. We conclude that the association with particle levels is more convincing than for SO(2), and without a threshold. Linear models provide an adequate estimation of the effect of particulate air pollution on mortality at low to moderate concentrations. PMID:11675264

  2. Trends in mercury wet deposition and mercury air concentrations across the U.S. and Canada.

    PubMed

    Weiss-Penzias, Peter S; Gay, David A; Brigham, Mark E; Parsons, Matthew T; Gustin, Mae S; Ter Schure, Arnout

    2016-10-15

    This study examined the spatial and temporal trends of mercury (Hg) in wet deposition and air concentrations in the United States (U.S.) and Canada between 1997 and 2013. Data were obtained from the National Atmospheric Deposition Program (NADP) and Environment Canada monitoring networks, and other sources. Of the 19 sites with data records from 1997-2013, 53% had significant negative trends in Hg concentration in wet deposition, while no sites had significant positive trends, which is in general agreement with earlier studies that considered NADP data up until about 2010. However, for the time period 2007-2013 (71 sites), 17% and 13% of the sites had significant positive and negative trends, respectively, and for the time period 2008-2013 (81 sites) 30% and 6% of the sites had significant positive and negative trends, respectively. Non-significant positive tendencies were also widespread. Regional trend analyses revealed significant positive trends in Hg concentration in the Rocky Mountains, Plains, and Upper Midwest regions for the recent time periods in addition to significant positive trends in Hg deposition for the continent as a whole. Sulfate concentration trends in wet deposition were negative in all regions, suggesting a lower importance of local Hg sources. The trend in gaseous elemental Hg from short-term datasets merged as one continuous record was broadly consistent with trends in Hg concentration in wet deposition, with the early time period (1998-2007) producing a significantly negative trend (-1.5±0.2%year(-1)) and the recent time period (2008-2013) displaying a flat slope (-0.3±0.1%year(-1), not significant). The observed shift to more positive or less negative trends in Hg wet deposition primarily seen in the Central-Western regions is consistent with the effects of rising Hg emissions from regions outside the U.S. and Canada and the influence of long-range transport in the free troposphere. PMID:26803218

  3. Enrichment of sulfate-reducing bacteria and resulting mineral formation in media mimicking pore water metal ion concentrations and pH conditions of acidic pit lakes.

    PubMed

    Meier, Jutta; Piva, Angela; Fortin, Danielle

    2012-01-01

    Acid mine drainage sites are extreme environments with high acidity and metal ion concentrations. Under anoxic conditions, microbial sulfate reduction may trigger the formation of secondary minerals as a result of H2S production and pH increase. This process was studied in batch experiments with enrichment cultures from acidic sediments of a pit lake using growth media set at different pH values and containing elevated concentrations of Fe²⁺ and Al³⁺. At initial pH values of 5 and 6, sulfate reduction occurred shortly after inoculation. Sulfate- reducing bacteria affiliated to the genus Desulfosporosinus predominated the microbial communities as shown by 16S rRNA gene analysis performed at the end of the incubation. At initial pH values of 3 and 4, sulfate reduction and cell growth occurred only after an extended lag phase, however, at a higher rate than in the less acidic assays. At the end of the growth phase, enrichments were dominated by Thermodesulfobium spp. suggesting that these sulfate reducers were better adapted to acidic conditions. Iron sulfides in the bulk phase were common in all assays, but specific aluminum precipitates formed in close association with cell surfaces and may function as a detoxification mechanism of dissolved Al species at low pH.

  4. Spatial & temporal variations of PM10 and particle number concentrations in urban air.

    PubMed

    Johansson, Christer; Norman, Michael; Gidhagen, Lars

    2007-04-01

    The size of particles in urban air varies over four orders of magnitude (from 0.001 microm to 10 microm in diameter). In many cities only particle mass concentrations (PM10, i.e. particles <10 microm diameter) is measured. In this paper we analyze how differences in emissions, background concentrations and meteorology affect the temporal and spatial distribution of PM10 and total particle number concentrations (PNC) based on measurements and dispersion modeling in Stockholm, Sweden. PNC at densely trafficked kerbside locations are dominated by ultrafine particles (<0.1 microm diameter) due to vehicle exhaust emissions as verified by high correlation with NOx. But PNC contribute only marginally to PM10, due to the small size of exhaust particles. Instead wear of the road surface is an important factor for the highest PM10 concentrations observed. In Stockholm, road wear increases drastically due to the use of studded tires and traction sand on streets during winter; up to 90% of the locally emitted PM10 may be due to road abrasion. PM10 emissions and concentrations, but not PNC, at kerbside are controlled by road moisture. Annual mean urban background PM10 levels are relatively uniformly distributed over the city, due to the importance of long range transport. For PNC local sources often dominate the concentrations resulting in large temporal and spatial gradients in the concentrations. Despite these differences in the origin of PM10 and PNC, the spatial gradients of annual mean concentrations due to local sources are of equal magnitude due to the common source, namely traffic. Thus, people in different areas experiencing a factor of 2 different annual PM10 exposure due to local sources will also experience a factor of 2 different exposure in terms of PNC. This implies that health impact studies based solely on spatial differences in annual exposure to PM10 may not separate differences in health effects due to ultrafine and coarse particles. On the other hand

  5. Spatial & temporal variations of PM10 and particle number concentrations in urban air.

    PubMed

    Johansson, Christer; Norman, Michael; Gidhagen, Lars

    2007-04-01

    The size of particles in urban air varies over four orders of magnitude (from 0.001 microm to 10 microm in diameter). In many cities only particle mass concentrations (PM10, i.e. particles <10 microm diameter) is measured. In this paper we analyze how differences in emissions, background concentrations and meteorology affect the temporal and spatial distribution of PM10 and total particle number concentrations (PNC) based on measurements and dispersion modeling in Stockholm, Sweden. PNC at densely trafficked kerbside locations are dominated by ultrafine particles (<0.1 microm diameter) due to vehicle exhaust emissions as verified by high correlation with NOx. But PNC contribute only marginally to PM10, due to the small size of exhaust particles. Instead wear of the road surface is an important factor for the highest PM10 concentrations observed. In Stockholm, road wear increases drastically due to the use of studded tires and traction sand on streets during winter; up to 90% of the locally emitted PM10 may be due to road abrasion. PM10 emissions and concentrations, but not PNC, at kerbside are controlled by road moisture. Annual mean urban background PM10 levels are relatively uniformly distributed over the city, due to the importance of long range transport. For PNC local sources often dominate the concentrations resulting in large temporal and spatial gradients in the concentrations. Despite these differences in the origin of PM10 and PNC, the spatial gradients of annual mean concentrations due to local sources are of equal magnitude due to the common source, namely traffic. Thus, people in different areas experiencing a factor of 2 different annual PM10 exposure due to local sources will also experience a factor of 2 different exposure in terms of PNC. This implies that health impact studies based solely on spatial differences in annual exposure to PM10 may not separate differences in health effects due to ultrafine and coarse particles. On the other hand

  6. Evaluation of an adsorption system to concentrate VOC in air streams prior to catalytic incineration.

    PubMed

    Campesi, María A; Luzi, Carlos D; Barreto, Guillermo F; Martínez, Osvaldo M

    2015-05-01

    Catalytic combustion is a well-developed process for the removal of volatile organic compounds (VOCs). In order to reduce both the amount of catalyst needed for incineration and the surface area of recuperative heat exchangers, an evaluation of the use of thermal swing adsorption as a previous step for VOC concentration is made. An air stream containing ethyl acetate and ethanol (employed as solvents in printing processes) has been taken as a case study. Based on the characteristics of the adsorption/desorption system and the properties of the stream to be treated, a monolithic rotor concentrator with activated carbon as adsorbent material is adopted. Once the temperature of the inlet desorption stream TD is chosen, the minimum possible desorption flow rate, WD,min, and the amount of adsorbent material can be properly defined according to the extent of the Mass Transfer Zone (MTZ) at the end of the adsorption stage. An approximate procedure to speed up the calculations needed for sizing the bed and predicting the operating variables is also presented. In the case studied here, the concentration of the VOC stream can reach 6 times that of the primary effluent when TD = 200 °C is chosen.

  7. Influence of precipitation on (7)Be concentrations in air as measured by CTBTO global monitoring system.

    PubMed

    Kusmierczyk-Michulec, J; Gheddou, A; Nikkinen, M

    2015-06-01

    Data collected by the International Monitoring System (IMS) during 2009-2012 were used to study influence of precipitation and relative humidity on changes in (7)Be concentrations in atmosphere. The significant decrease in (7)Be concentrations, corresponding to measurements collected by stations located within Intertropical Convergence Zone (ITCZ) is demonstrated. This effect can be attributed to the process of enhanced wet deposition within the ITCZ. To quantify this effect data collected by IMS stations within ITCZ were thoroughly analyzed. It was found that the atmospheric content of (7)Be strongly decreases under the rain conditions. The rain mediated depletion of (7)Be to half of its before rain value, needs about 62 h in case of light precipitation, while in the case of moderate precipitation about 38 h is needed. In addition the evaluated impact of humidity showed that increase in relative humidity by 20%, for example from 70% ± 5% to 90% ± 5% causes almost a double decrease in beryllium concentration in surface air.

  8. Evaluation of an adsorption system to concentrate VOC in air streams prior to catalytic incineration.

    PubMed

    Campesi, María A; Luzi, Carlos D; Barreto, Guillermo F; Martínez, Osvaldo M

    2015-05-01

    Catalytic combustion is a well-developed process for the removal of volatile organic compounds (VOCs). In order to reduce both the amount of catalyst needed for incineration and the surface area of recuperative heat exchangers, an evaluation of the use of thermal swing adsorption as a previous step for VOC concentration is made. An air stream containing ethyl acetate and ethanol (employed as solvents in printing processes) has been taken as a case study. Based on the characteristics of the adsorption/desorption system and the properties of the stream to be treated, a monolithic rotor concentrator with activated carbon as adsorbent material is adopted. Once the temperature of the inlet desorption stream TD is chosen, the minimum possible desorption flow rate, WD,min, and the amount of adsorbent material can be properly defined according to the extent of the Mass Transfer Zone (MTZ) at the end of the adsorption stage. An approximate procedure to speed up the calculations needed for sizing the bed and predicting the operating variables is also presented. In the case studied here, the concentration of the VOC stream can reach 6 times that of the primary effluent when TD = 200 °C is chosen. PMID:25734958

  9. Evaluation of optical source-detector configurations for tomographic reconstruction of chemical concentrations in indoor air.

    PubMed

    Todd, L; Ramachandran, G

    1994-12-01

    This article reports on numerical studies to evaluate and compare optical remote sensing configurations for tomographically reconstructing pollutant concentrations in indoor air. With a remote sensing/computed tomography system, two-dimensional maps of pollutant concentrations with good spatial resolution can be created for an entire room. The successful use of such a system for exposure assessment, ventilation assessment, or source monitoring depends on the remote sensing configuration. A systematic method was developed to evaluate the performance of 10 configurations. One hundred and twenty test maps were reconstructed with an algebraic reconstruction method using all 10 configurations; reconstruction quality was evaluated using 4 criteria. Reconstruction quality was related to the number and location of detectors in the room and the complexity of the test maps. Configurations using the same number of detectors placed in different locations resulted in reconstructions that differed in quality. The effect of reducing the number density of rays on reconstruction quality was studied. Based on these simulations, two configurations that used four detectors to scan the room were selected, and their performance was evaluated in the presence of various levels of measurement noise. Two configurations that used four detectors were most suited for exposure assessment. It was found that when designing a configuration, the number and independence of rays should be maximized. Results underscored the need to thoroughly test configurations through numerical studies prior to field implementation; a wide variety of concentration maps, relevant to the application, should be tested under both ideal and nonideal sampling conditions. PMID:7825513

  10. Seasonal variations in concentrations, distributions, and air-soil exchange fluxes of dioxin-like polychlorinated biphenyls in Shanghai, China.

    PubMed

    Tian, Yajun; Nie, Zhiqiang; He, Jie; Die, Qingqi; Fang, Yanyan; Liu, Feng; Yang, Yufei; Gao, Xingbao; Huang, Qifei

    2016-02-01

    Dioxin-like polychlorinated biphenyl (dl-PCB) concentrations in ambient air and soil in Shanghai, China, were measured to allow seasonal and spatial differences in the dl-PCB concentrations, profiles, distributions, fugacity fractions, and air-soil fluxes to be determined. The toxic equivalent (TEQ) DL-PCB concentrations in the air were higher in summer (mean 9.46 fg m(-3), range 1.32-26.3 fg m(-3)) than in winter (mean 4.57 fg m(-3), range 1.55-10.9 fg m(-3)). The DL-PCB concentrations in air were different in different areas, and the concentrations decreased in the order industrial areas > commercial and residential areas > suburban areas > rural area. The mean DL-PCB concentration in soil was 0.25 pg TEQ g(-1) dry weight (dw) and the range was 0.05-0.90 pg TEQ g(-1) dw. The highest DL-PCB concentration in soil was found in a sample from a commercial/residential area. The DL-PCB fluxes were negative (-216 pg m(-2) h(-1) in summer and -41.1 pg m(-2) h(-1) in winter), and the fugacity fractions were below 0.5, indicating that dl-PCBs in Shanghai are deposited from the air to the soil in all seasons. The net fluxes were higher in summer than in winter, and the deposition fluxes were higher in industrial areas than in other areas in both summer and winter.

  11. Solutions, Unit 2: Molarity, Molality, Concentration Conversions. A Computer-Enriched Module for Introductory Chemistry. Student's Guide and Teacher's Guide.

    ERIC Educational Resources Information Center

    Bader, Morris

    Presented are the teacher's guide and student manual for one of a series of self-instructional, computer-based learning modules for an introductory, undergraduate chemistry course. The student module for this solution concentration unit includes objectives, prerequisites, pretest, discussion, and 20 problem sets. Included in the teacher's guide…

  12. [Concentration of allergic fungi spores in the air of flats in Lódź].

    PubMed

    Krawczyk, P; Kowalski, M L; Ochecka-Szymańska, A

    1999-01-01

    The real contribution of moulds to the pathogenesis of allergic diseases remains unknown, although positive skin prick tests and/or specific serum IgE to moki allergens can be detected in 1-5% of atopic patients. A significant problem in assesment of exposure to mould allergens, resulting with difficulty in standarization of methods. The aim of this work was to assess the concentration of spores of 8 mould species in flats inhabited by peoples who Bont show any symptoms of allergy. The Open Petri Dish (OPD) method involving sedimentation of participles contained in the column of air over the dish was used to assess the number of spores in 1 m3 of indoor atmospheres. All colonies were counted, but only 8 mould species implicated in inhaled allergy were identified, ie.: Alternaria tenuis, Cladosporium herbarum, Helminthosporum halodes, Pullularia pullulans, Penicillium notatam, Rhizopus nigricans, Mucor mucedo, Aspergillus fumigatus. The tests were carried out in 10 flats located in various quarters of the cify of Lodź during three consecutive days of September 1995 between 5:00 pm and 6:04 pm. In analyzing the percentage of spores of each of the eight mould species tested we determined that, independent of fiat and test day, C. herbarum predominated. It is good agreement with the observations of other authors who report that among large quantities of fungi that are detected in late summer, usually C. herbarum spores dominate. This is the season when the incidence of the Cladosporium spores in the atmospheric air increases. Spores of H. halodes were detected least frequently. Our study demonstrated the presence of substantial amounts of mould spores in indoor air of houses in Lódź. The spores belong to species with documented allergenicity, suggesting that they may play a role in development of allergic sensitization in susceptible subjects.

  13. Effects of trans-Eurasian transport of air pollutants on surface ozone concentrations over Western China

    NASA Astrophysics Data System (ADS)

    Li, Xiaoyuan; Liu, Junfeng; Mauzerall, Denise L.; Emmons, Louisa K.; Walters, Stacy; Horowitz, Larry W.; Tao, Shu

    2014-11-01

    Due to a lack of industrialization in Western China, surface air there was, until recently, believed to be relatively unpolluted. However, recent measurements and modeling studies have found high levels of ozone (O3) there. Based on the state-of-the-science global chemical transport model MOZART-4, we identify the origin, pathway, and mechanism of trans-Eurasian transport of air pollutants to Western China in 2000. MOZART-4 generally simulates well the observed surface O3 over inland areas of China. Simulations find surface ozone concentrations over Western China on average to be about 10 ppbv higher than Eastern China. Using sensitivity studies, we find that anthropogenic emissions from all Eurasian regions except China contribute 10-15 ppbv surface O3 over Western China, superimposed upon a 35-40 ppbv natural background. Transport from European anthropogenic sources to Northwestern China results in 2-6 ppbv O3 enhancements in spring and summer. Indian anthropogenic sources strongly influence O3 over the Tibetan Plateau during the summer monsoon. Transport of O3 originating from emissions in the Middle East occasionally reach Western China and increase surface ozone there by about 1-4 ppbv. These influences are of similar magnitude as trans-Pacific and transatlantic transport of O3 and its precursors, indicating the significance of trans-Eurasian ozone transport in hemispheric transport of air pollution. Our study further indicates that mitigation of anthropogenic emissions from Europe, the Indian subcontinent, and the Middle East could benefit public health and agricultural productivity in Western China.

  14. [Concentration of allergic fungi spores in the air of flats in Lódź].

    PubMed

    Krawczyk, P; Kowalski, M L; Ochecka-Szymańska, A

    1999-01-01

    The real contribution of moulds to the pathogenesis of allergic diseases remains unknown, although positive skin prick tests and/or specific serum IgE to moki allergens can be detected in 1-5% of atopic patients. A significant problem in assesment of exposure to mould allergens, resulting with difficulty in standarization of methods. The aim of this work was to assess the concentration of spores of 8 mould species in flats inhabited by peoples who Bont show any symptoms of allergy. The Open Petri Dish (OPD) method involving sedimentation of participles contained in the column of air over the dish was used to assess the number of spores in 1 m3 of indoor atmospheres. All colonies were counted, but only 8 mould species implicated in inhaled allergy were identified, ie.: Alternaria tenuis, Cladosporium herbarum, Helminthosporum halodes, Pullularia pullulans, Penicillium notatam, Rhizopus nigricans, Mucor mucedo, Aspergillus fumigatus. The tests were carried out in 10 flats located in various quarters of the cify of Lodź during three consecutive days of September 1995 between 5:00 pm and 6:04 pm. In analyzing the percentage of spores of each of the eight mould species tested we determined that, independent of fiat and test day, C. herbarum predominated. It is good agreement with the observations of other authors who report that among large quantities of fungi that are detected in late summer, usually C. herbarum spores dominate. This is the season when the incidence of the Cladosporium spores in the atmospheric air increases. Spores of H. halodes were detected least frequently. Our study demonstrated the presence of substantial amounts of mould spores in indoor air of houses in Lódź. The spores belong to species with documented allergenicity, suggesting that they may play a role in development of allergic sensitization in susceptible subjects. PMID:16886472

  15. A critical review of reported air concentrations of organic compounds in aircraft cabins.

    PubMed

    Nagda, N L; Rector, H E

    2003-09-01

    This paper presents a review and assessment of aircraft cabin air quality studies with measured levels of volatile and semivolatile organic compounds (VOCs and SVOCs). VOC and SVOC concentrations reported for aircraft cabins are compared with those reported for residential and office buildings and for passenger compartments of other types of transportation. An assessment of measurement technologies and quality assurance procedures is included. The six studies reviewed in the paper range in coverage from two to about 30 flights per study. None of the monitored flights included any unusual or episodic events that could affect cabin air quality. Most studies have used scientifically sound methods for measurements. Study results indicate that under routine aircraft operations, contaminant levels in aircraft cabins are similar to those in residential and office buildings, with two exceptions: (1). levels of ethanol and acetone, indicators of bioeffluents and chemicals from consumer products are higher in aircraft than in home or office environments, and (2). levels of certain chlorinated hydrocarbons and fuel-related contaminants are higher in residential/office buildings than in aircraft. Similarly, ethanol and acetone levels are higher in aircraft than in other transportation modes but the levels of some pollutants, such as m-/p-xylenes, tend to be lower in aircraft.

  16. Determination of the concentration and isotopic composition of uranium in environmental air filters

    SciTech Connect

    Russ, G.P. III; Bazan, J.M.

    1994-08-26

    For many years, Lawrence Livermore National Laboratory has collected monthly air-particulate filter samples from a variety of environmental monitoring stations on and off site. Historically the concentration and isotopic composition of uranium collected on these filters was determined by isotope dilution using a {sup 233}U spike and thermal ionization mass spectrometry (TIMS). For samples containing as little as 10 nanograms of uranium, ICP-MS is now used to make these measurements to the required level of precision, about 5% in the measured 235/238 and 233/238. Unless particular care is taken to control bias in the mass filter, variable mass bias limits accuracy to a few percent. Measurements of the minor isotopes 236 (if present) and 234 are also possible and provide useful information for identifying the source of the uranium. The advantage of ICP-MS is in rapid analysis, {approximately}12 minutes of instrument time per sample.

  17. Water complexes of important air pollutants: geometries, complexation energies, concentrations, infrared spectra, and intrinsic reactivity.

    PubMed

    Galano, Annia; Narciso-Lopez, Marcela; Francisco-Marquez, Misaela

    2010-05-13

    Water complexes involving methanol, ethanol, formaldehyde, formic acid, acetone, ammonia, acetylene, ethylene, chloroethene, trichloroethene, 1,1,1-trichloroethane, hydroxyl radical, and hydroperoxyl radical have been studied. Enthalpies, entropies, and Gibbs free energies of association have been estimated, as well as the concentrations of the complexes under lower-troposphere conditions. The influence of the relative air humidity on the complexation processes has been analyzed. The association processes yielding water complexes of methanol, ethanol, formic acid, ammonia, acetone, hydroxyl radical, and hydroperoxyl radical were found to be more exothermic than that of the water dimer. General trends for the reactivity of the studied water complexes, compared to those of the corresponding free species, are proposed based on global reactivity indexes. The previously reported increased reactivity of the (*)OOH self-reaction, when there is water present, has been explained. The IR spectra of the complexes have been analyzed and compared with those of the free species. PMID:20394451

  18. Determinants of perceived air pollution annoyance and association between annoyance scores and air pollution (PM 2.5, NO 2) concentrations in the European EXPOLIS study

    NASA Astrophysics Data System (ADS)

    Rotko, Tuulia; Oglesby, Lucy; Künzli, Nino; Carrer, Paolo; Nieuwenhuijsen, Mark J.; Jantunen, Matti

    Apart from its traditionally considered objective impacts on health, air pollution can also have perceived effects, such as annoyance. The psychological effects of air pollution may often be more important to well-being than the biophysical effects. Health effects of perceived annoyance from air pollution are so far unknown. More knowledge of air pollution annoyance levels, determinants and also associations with different air pollution components is needed. In the European air pollution exposure study, EXPOLIS, the air pollution annoyance as perceived at home, workplace and in traffic were surveyed among other study objectives. Overall 1736 randomly drawn 25-55-yr-old subjects participated in six cities (Athens, Basel, Milan, Oxford, Prague and Helsinki). Levels and predictors of individual perceived annoyances from air pollution were assessed. Instead of the usual air pollution concentrations at fixed monitoring sites, this paper compares the measured microenvironment concentrations and personal exposures of PM 2.5 and NO 2 to the perceived annoyance levels. A considerable proportion of the adults surveyed was annoyed by air pollution. Female gender, self-reported respiratory symptoms, downtown living and self-reported sensitivity to air pollution were directly associated with high air pollution annoyance score while in traffic, but smoking status, age or education level were not significantly associated. Population level annoyance averages correlated with the city average exposure levels of PM 2.5 and NO 2. A high correlation was observed between the personal 48-h PM 2.5 exposure and perceived annoyance at home as well as between the mean annoyance at work and both the average work indoor PM 2.5 and the personal work time PM 2.5 exposure. With the other significant determinants (gender, city code, home location) and home outdoor levels the model explained 14% (PM 2.5) and 19% (NO 2) of the variation in perceived air pollution annoyance in traffic. Compared to

  19. Photosynthesis, productivity, and yield of maize are not affected by open-air elevation of CO2 concentration in the absence of drought.

    PubMed

    Leakey, Andrew D B; Uribelarrea, Martin; Ainsworth, Elizabeth A; Naidu, Shawna L; Rogers, Alistair; Ort, Donald R; Long, Stephen P

    2006-02-01

    While increasing temperatures and altered soil moisture arising from climate change in the next 50 years are projected to decrease yield of food crops, elevated CO2 concentration ([CO2]) is predicted to enhance yield and offset these detrimental factors. However, C4 photosynthesis is usually saturated at current [CO2] and theoretically should not be stimulated under elevated [CO2]. Nevertheless, some controlled environment studies have reported direct stimulation of C4 photosynthesis and productivity, as well as physiological acclimation, under elevated [CO2]. To test if these effects occur in the open air and within the Corn Belt, maize (Zea mays) was grown in ambient [CO2] (376 micromol mol(-1)) and elevated [CO2] (550 micromol mol(-1)) using Free-Air Concentration Enrichment technology. The 2004 season had ideal growing conditions in which the crop did not experience water stress. In the absence of water stress, growth at elevated [CO2] did not stimulate photosynthesis, biomass, or yield. Nor was there any CO2 effect on the activity of key photosynthetic enzymes, or metabolic markers of carbon and nitrogen status. Stomatal conductance was lower (-34%) and soil moisture was higher (up to 31%), consistent with reduced crop water use. The results provide unique field evidence that photosynthesis and production of maize may be unaffected by rising [CO2] in the absence of drought. This suggests that rising [CO2] may not provide the full dividend to North American maize production anticipated in projections of future global food supply. PMID:16407441

  20. Evaluation of ambient air concentrations of polycyclic aromatic hydrocarbons in Germany from 1990 to 1998.

    PubMed

    Fertmann, Regina; Tesseraux, Irene; Schümann, Michael; Neus, Hermann

    2002-03-01

    All available polycyclic aromatic hydrocarbon (PAH) concentration data in ambient air obtained over the past 10 years in Germany were evaluated to clarify whether it is justified to use benzo(a)pyrene (BaP) as a marker compound for the total PAH exposure. The data basis comprises annual mean concentrations from 1990 to 1998 supplied by the emission protection authorities of the federal states with additional information on the region, year and site of measurement. The data are very heterogeneous with respect to sample size, the number of individual PAHs analyzed, place of origin and year. Nine of 25 individual compounds with sufficient sample size (74concentration data of BaA, BeP, BaP, DBA, BghiP, COR, BbF, BkF and INP are not normally distributed and demonstrate great variability. Location, East-West differences persisting after the German reunion and time characterize the distributive patterns, e.g., from 1991 to 1997, a significant decrease in BaP could be determined based on the data from North Rhine-Westphalia (1991, N=51, median 1.6 ng/m(3); 1997, N=45, median 0.7 ng/m(3); Pconcentrations in the new federal states in the East (N=80, median 2.2 ng/m(3)) are about twice as high compared to the ones in the old federal states in the West (N=438, median 1.1 ng/m(3); P

  1. Measurements of soot, OH, and PAH concentrations in turbulent ethylene/air jet flames

    SciTech Connect

    Lee, Seong-Young; Turns, Stephen R.; Santoro, Robert J.

    2009-12-15

    This paper presents results from an investigation of soot formation in turbulent, non-premixed, C{sub 2}H{sub 4}/air jet flames. Tests were conducted using a H{sub 2}-piloted burner with fuel issuing from a 2.18 mm i.d. tube into quiescent ambient air. A range of test conditions was studied using the initial jet velocity (16.2-94.1 m/s) as a parameter. Fuel-jet Reynolds numbers ranged from 4000 to 23,200. Planar laser-induced incandescence (LII) was employed to determine soot volume fractions, and laser-induced fluorescence (LIF) was used to measure relative hydroxyl radical (OH) concentrations and polycyclic aromatic hydrocarbons (PAHs) concentrations. Extensive information on the structure of the soot and OH fields was obtained from two-dimensional imaging experiments. Quantitative measurements were obtained by employing the LII and LIF techniques independently. Imaging results for soot, OH, and PAH show the existence of three soot formation/oxidation regions: a rapid soot growth region, in which OH and soot particles lie in distinctly different radial locations; a mixing-dominated region controlled by large-scale motion; and a soot-oxidation region in which the OH and soot fields overlap spatially, resulting in the rapid oxidation of soot particles. Detailed quantitative analyzes of soot volume fractions and OH and soot zone thicknesses were performed along with the temperature measurement using the N{sub 2}-CARS system. Measurements of OH and soot zone thicknesses show that the soot zone thickness increases linearly with axial distance in the soot formation region, whereas the OH zone thickness is nearly constant in this region. The OH zone thickness then rapidly increases with downstream distance and approximately doubles in the soot-oxidation region. Probability density functions also were obtained for soot volume fractions and OH concentrations. These probability density functions clearly define the spatial relationships among the OH, PAH concentrations, the

  2. A modeling framework for characterizing near-road air pollutant concentration at community scales.

    PubMed

    Chang, Shih Ying; Vizuete, William; Valencia, Alejandro; Naess, Brian; Isakov, Vlad; Palma, Ted; Breen, Michael; Arunachalam, Saravanan

    2015-12-15

    In this study, we combine information from transportation network, traffic emissions, and dispersion model to develop a framework to inform exposure estimates for traffic-related air pollutants (TRAPs) with a high spatial resolution. A Research LINE source dispersion model (R-LINE) is used to model multiple TRAPs from roadways at Census-block level for two U.S. regions. We used a novel Space/Time Ordinary Kriging (STOK) approach that uses data from monitoring networks to provide urban background concentrations. To reduce the computational burden, we developed and applied the METeorologically-weighted Averaging for Risk and Exposure (METARE) approach with R-LINE, where a set of selected meteorological data and annual average daily traffic (AADT) are used to obtain annual averages. Compared with explicit modeling, using METARE reduces CPU-time by 88-fold (46.8h versus 32min), while still retaining accuracy of exposure estimates. We show two examples in the Piedmont region in North Carolina (~105,000 receptors) and Portland, Maine (~7000 receptors) to characterize near-road air quality. Concentrations for NOx, PM2.5, and benzene in Portland drop by over 40% within 200m away from the roadway. The concentration drop in North Carolina is less than that in Portland, as previously shown in an observation-based study, showing the robustness of our approach. Heavy-duty diesel vehicles (HDDV) contribute over 55% of NOx and PM2.5 near interstate highways, while light-duty gasoline vehicles (LDGV) contribute over 50% of benzene to urban areas where multiple roadways intersect. Normalized mean error (NME) between explicit modeling and METARE in Portland ranges from 12.6 to 14.5% and normalized mean bias (NMB) ranges from -12.9 to -11.2%. When considering a static emission rate (i.e. the emission does not have temporal variability), both NME and NMB improved (10.5% and -9.5%). Modeled concentrations in Detroit, Michigan at an array of near-road monitors are within a factor of 2

  3. A modeling framework for characterizing near-road air pollutant concentration at community scales.

    PubMed

    Chang, Shih Ying; Vizuete, William; Valencia, Alejandro; Naess, Brian; Isakov, Vlad; Palma, Ted; Breen, Michael; Arunachalam, Saravanan

    2015-12-15

    In this study, we combine information from transportation network, traffic emissions, and dispersion model to develop a framework to inform exposure estimates for traffic-related air pollutants (TRAPs) with a high spatial resolution. A Research LINE source dispersion model (R-LINE) is used to model multiple TRAPs from roadways at Census-block level for two U.S. regions. We used a novel Space/Time Ordinary Kriging (STOK) approach that uses data from monitoring networks to provide urban background concentrations. To reduce the computational burden, we developed and applied the METeorologically-weighted Averaging for Risk and Exposure (METARE) approach with R-LINE, where a set of selected meteorological data and annual average daily traffic (AADT) are used to obtain annual averages. Compared with explicit modeling, using METARE reduces CPU-time by 88-fold (46.8h versus 32min), while still retaining accuracy of exposure estimates. We show two examples in the Piedmont region in North Carolina (~105,000 receptors) and Portland, Maine (~7000 receptors) to characterize near-road air quality. Concentrations for NOx, PM2.5, and benzene in Portland drop by over 40% within 200m away from the roadway. The concentration drop in North Carolina is less than that in Portland, as previously shown in an observation-based study, showing the robustness of our approach. Heavy-duty diesel vehicles (HDDV) contribute over 55% of NOx and PM2.5 near interstate highways, while light-duty gasoline vehicles (LDGV) contribute over 50% of benzene to urban areas where multiple roadways intersect. Normalized mean error (NME) between explicit modeling and METARE in Portland ranges from 12.6 to 14.5% and normalized mean bias (NMB) ranges from -12.9 to -11.2%. When considering a static emission rate (i.e. the emission does not have temporal variability), both NME and NMB improved (10.5% and -9.5%). Modeled concentrations in Detroit, Michigan at an array of near-road monitors are within a factor of 2

  4. Elevated CO2 levels affects the concentrations of copper and cadmium in crops grown in soil contaminated with heavy metals under fully open-air field conditions.

    PubMed

    Guo, Hongyan; Zhu, Jianguo; Zhou, Hui; Sun, Yuanyuan; Yin, Ying; Pei, Daping; Ji, Rong; Wu, Jichun; Wang, Xiaorong

    2011-08-15

    Elevated CO(2) levels and the increase in heavy metals in soils through pollution are serious problems worldwide. Whether elevated CO(2) levels will affect plants grown in heavy-metal-polluted soil and thereby influence food quality and safety is not clear. Using a free-air CO(2) enrichment (FACE) system, we investigated the impacts of elevated atmospheric CO(2) on the concentrations of copper (Cu) or cadmium (Cd) in rice and wheat grown in soil with different concentrations of the metals in the soil. In the two-year study, elevated CO(2) levels led to lower Cu concentrations and higher Cd concentrations in shoots and grain of both rice and wheat grown in the respective contaminated soil. Elevated CO(2) levels slightly but significantly lowered the pH of the soil and led to changes in Cu and Cd fractionation in the soil. Our study indicates that elevated CO(2) alters the distribution of contaminant elements in soil and plants, thereby probably affecting food quality and safety.

  5. Soil air CO2 concentration as an integrative parameter of soil structure

    NASA Astrophysics Data System (ADS)

    Ebeling, Corinna; Gaertig, Thorsten; Fründ, Heinz-Christian

    2015-04-01

    The assessment of soil structure is an important but difficult issue and normally takes place in the laboratory. Typical parameters are soil bulk density, porosity, water or air conductivity or gas diffusivity. All methods are time-consuming. The integrative parameter soil air CO2 concentration ([CO2]) can be used to assess soil structure in situ and in a short time. Several studies highlighted that independent of soil respiration, [CO2] in the soil air increases with decreasing soil aeration. Therefore, [CO2] is a useful indicator of soil aeration. Embedded in the German research project RÜWOLA, which focus on soil protection at forest sites, we investigated soil compaction and recovery of soil structure after harvesting. Therefore, we measured soil air CO2 concentrations continuously and in single measurements and compared the results with the measurements of bulk density, porosity and gas diffusivity. Two test areas were investigated: At test area 1 with high natural regeneration potential (clay content approx. 25 % and soil-pH between 5 and 7), solid-state CO2-sensors using NDIR technology were installed in the wheel track of different aged skidding tracks in 5 and 10 cm soil depths. At area 2 (acidic silty loam, soil-pH between 3.5 and 4), CO2-sensors and water-tension sensors (WatermarkR) were installed in 6 cm soil depth. The results show a low variance of [CO2] in the undisturbed soil with a long term mean from May to June 2014 between 0.2 and 0.5 % [CO2] in both areas. In the wheel tracks [CO2] was consistently higher. The long term mean [CO2] in the 8-year-old-wheel track in test area 1 is 5 times higher than in the reference soil and shows a high variation (mean=2.0 %). The 18-year-old wheel track shows a long-term mean of 1.2 % [CO2]. Furthermore, there were strong fluctuations of [CO2] in the wheel tracks corresponding to precipitation and humidity. Similar results were yielded with single measurements during the vegetation period using a portable

  6. Soil Carbon Storage and N{sub 2}O Emissions from Wheat Agroecosystems as Affected by Free-Air CO{sub 2} Enrichment (FACE) and Nitrogen Treatments. Annual Progress Report - Year 1: August 1, 1996 to July 31, 1997 [Final Report

    SciTech Connect

    Leavitt, S.W.; Matthias, A.; Thompson, T.L.

    1999-02-17

    Rising atmospheric CO{sub 2} concentrations have prompted concern about response of plants and crops to future elevated CO{sub 2} levels, and particularly the extent to which ecosystems will sequester carbon and thus impact the rate of rise of CO{sub 2} concentrations. Free-air CO{sub 2} enrichment (FACE) experimentation was used with wheat agroecosystems for two growing seasons to assess effects of CO{sub 2} and soil nitrogen. Over 20 researchers on this experiment variously examined plant production and grow yield, phenology, length of growing season, water-use efficiency, ecosystem productivity, below ground processes (root and microbial activity, carbon and nitrogen cycling), etc.

  7. Variation of radon-222 concentration in exposure systems air under different conditions of exposure

    NASA Astrophysics Data System (ADS)

    Mamoon, A.; Abdul-Fattah, A. A.; Qari, T. M.

    1994-07-01

    Simplified, laboratory scale systems, namely ordinary laboratory desiccators and cylindrical containers were tested with regard to their reliability as exposure systems for determining certain parameters of radon emanation from locally obtained crushed granite rock samples. The samples were placed inside the exposure systems. Activity concentration of emanated radon in the exposure systems air increased with increase of mass of granite sample in the desiccator and with length of the exposure period. Activity concentration of radon was high near the granitic source but decreased with vertical distance from it when the exposure system was semiclosed but activity was homogeneous when the system was completely closed. The cylindrical exposure system was used in assessing Ra-226 content in some crushed granitic samples identified as altered alkali granite and found to be: 0.024 Bq g-1 (0.65 pCig-1). Rn-222 emanation rate from the same samples was: 0.013 Bq m-2 s-1 (0.34 pCi m-2 s-1). Saturation density thickness for a mixed sample of pure and alkali granites was found to be 116 g cm-2. The results agree in general with reported observations and support the reliability of the exposure systems used.

  8. Low pCO2 Air-Polarized CO2 Concentrator Development

    NASA Technical Reports Server (NTRS)

    Schubert, Franz H.

    1997-01-01

    Life Systems completed a Ground-based Space Station Experiment Development Study Program which verifies through testing the performance and applicability of the electrochemical Air-Polarized Carbon Dioxide Concentrator (APC) process technology for space missions requiring low (i.e., less than 3 mm Hg) CO2 partial pressure (pCO2) in the cabin atmosphere. Required test hardware was developed and testing was accomplished at an approximate one-person capacity CO2 removal level. Initially, two five-cell electrochemical modules using flight-like 0.5 sq ft cell hardware were tested individually, following by their testing at the integrated APC system level. Testing verified previously projected performance and established a database for sizing of APC systems. A four person capacity APC system was sized and compared with four candidate CO2 removal systems. At its weight of 252 lb, a volume of 7 cu ft and a power consumption of 566 W while operating at 2.2 mm Hg pCO2, the APC was surpassed only by an Electrochemical Depolarized CO2 Concentrator (EDC) (operating with H2), when compared on a total equivalent basis.

  9. Air flow and concentration fields at urban road intersections for improved understanding of personal exposure.

    PubMed

    Tiwary, Abhishek; Robins, Alan; Namdeo, Anil; Bell, Margaret

    2011-07-01

    This paper reviews the state of knowledge on modelling air flow and concentration fields at road intersections. The first part covers the available literature from the past two decades on experimental (both field and wind tunnel) and modelling activities in order to provide insight into the physical basis of flow behaviour at a typical cross-street intersection. This is followed by a review of associated investigations of the impact of traffic-generated localised turbulence on the concentration fields due to emissions from vehicles. There is a discussion on the role of adequate characterisation of vehicle-induced turbulence in making predictions using hybrid models, combining the merits of conventional approaches with information obtained from more detailed modelling. This concludes that, despite advancements in computational techniques, there are crucial knowledge gaps affecting the parameterisations used in current models for individual exposure. This is specifically relevant to the growing impetus on walking and cycling activities on urban roads in the context of current drives for sustainable transport and healthy living. Due to inherently longer travel times involved during such trips, compared to automotive transport, pedestrians and cyclists are subjected to higher levels of exposure to emissions. Current modelling tools seem to under-predict this exposure because of limitations in their design and in the empirical parameters employed.

  10. Air flow and concentration fields at urban road intersections for improved understanding of personal exposure.

    PubMed

    Tiwary, Abhishek; Robins, Alan; Namdeo, Anil; Bell, Margaret

    2011-07-01

    This paper reviews the state of knowledge on modelling air flow and concentration fields at road intersections. The first part covers the available literature from the past two decades on experimental (both field and wind tunnel) and modelling activities in order to provide insight into the physical basis of flow behaviour at a typical cross-street intersection. This is followed by a review of associated investigations of the impact of traffic-generated localised turbulence on the concentration fields due to emissions from vehicles. There is a discussion on the role of adequate characterisation of vehicle-induced turbulence in making predictions using hybrid models, combining the merits of conventional approaches with information obtained from more detailed modelling. This concludes that, despite advancements in computational techniques, there are crucial knowledge gaps affecting the parameterisations used in current models for individual exposure. This is specifically relevant to the growing impetus on walking and cycling activities on urban roads in the context of current drives for sustainable transport and healthy living. Due to inherently longer travel times involved during such trips, compared to automotive transport, pedestrians and cyclists are subjected to higher levels of exposure to emissions. Current modelling tools seem to under-predict this exposure because of limitations in their design and in the empirical parameters employed. PMID:21435722

  11. Removal of low-concentration BTX in air using a combined plasma catalysis system.

    PubMed

    Fan, X; Zhu, T L; Wang, M Y; Li, X M

    2009-06-01

    The behavior of non-thermal plasma (NTP) and combined plasma catalysis (CPC) was investigated for removal of low-concentration benzene, toluene and p-xylene (BTX mixture) in air using a link tooth wheel-cylinder plasma reactor. Combining NTP with MnO(x)/Al(2)O(3) catalyst after the discharge zone (CPC) significantly promoted BTX conversion and improved the energy efficiency. For a specific input energy (SIE) of 10 JL(-1), the conversion of benzene, toluene and p-xylene reached 94%, 97% and 95%, respectively. The introduction of MnO(x)/Al(2)O(3) catalyst also moved the BTX conversion towards total oxidation and reduced the emission of O(3) and NO(2) as compared to NTP alone. For an SIE of 10 JL(-1), the O(3) outlet concentration decreased from 46.7 for NTP alone to 1.9 ppm for CPC, while the NO(2) emission correspondingly decreased from 1380 to 40 ppb.

  12. Effect of chimneys on indoor air concentrations of PM 10 and benzo[a]pyrene in Xuan Wei, China

    NASA Astrophysics Data System (ADS)

    Tian, Linwei; Lan, Qing; Yang, Dong; He, Xingzhou; Yu, Ignatius T. S.; Hammond, S. Katharine

    This paper reports the effect of chimneys in reducing indoor air pollution in a lung cancer epidemic area of rural China. Household indoor air pollution concentrations were measured during unvented burning (chimneys blocked) and vented burning (chimneys open) of bituminous coal in Xuan Wei, China. Concentrations of particulate matter with an aerodynamic diameter of 10 μm or less (PM 10) and of benzo[a]pyrene (BaP) were measured in 43 homes during normal activities. The use of chimneys led to significant decreases in indoor air concentrations of particulate matter with an aerodynamic diameter of 10 μm or less (PM 10) by 66% and of benzo[a]pyrene (BaP) by 84%. The average BaP content of PM 10 also decreased by 55% with the installation of a chimney. The reduction of indoor pollution levels by the installation of a chimney supports the epidemiology findings on the health benefits of stove improvement. However, even in the presence of a chimney, the indoor air concentrations for both PM 10 and BaP still exceeded the indoor air quality standards of China. Movement up the energy ladder to cleaner liquid or gaseous fuels is probably the only sustainable indoor air pollution control measure.

  13. Short-term environmental enrichment, in the absence of exercise, improves memory, and increases NGF concentration, early neuronal survival, and synaptogenesis in the dentate gyrus in a time-dependent manner.

    PubMed

    Birch, Amy M; McGarry, Niamh B; Kelly, Aine M

    2013-06-01

    Environmental manipulations can enhance neuroplasticity in the brain, with enrichment-induced cognitive improvements being linked to increased expression of growth factors, such as neurotrophins, and enhanced hippocampal neurogenesis. There is, however, a great deal of variation in environmental enrichment protocols used in the literature, making it difficult to assess the role of particular aspects of enrichment upon memory and the underlying associated mechanisms. This study sought to evaluate the efficacy of environmental enrichment, in the absence of exercise, as a cognitive enhancer and assess the role of Nerve Growth Factor (NGF), neurogenesis and synaptogenesis in this process. We report that rats housed in an enriched environment for 3 and 6 weeks (wk) displayed improved recognition memory, while rats enriched for 6 wk also displayed improved spatial and working memory. Neurochemical analyses revealed significant increases in NGF concentration and subgranular progenitor cell survival (as measured by BrdU+ nuclei) in the dentate gyrus of rats enriched for 6 wk, suggesting that these cellular changes may mediate the enrichment-induced memory improvements. Further analysis revealed a significant positive correlation between recognition task performance and BrdU+ nuclei. In addition, rats enriched for 6 wk showed a significant increase in expression of synaptophysin and synapsin I in the dentate gyrus, indicating that environmental enrichment can increase synaptogenesis. These data indicate a time-dependent cognitive-enhancing effect of environmental enrichment that is independent of physical activity. These data also support a role for increased concentration of NGF in dentate gyrus, synaptogenesis, and neurogenesis in mediating this effect.

  14. Air pollutants in rural homes in Guizhou, China - Concentrations, speciation, and size distribution

    NASA Astrophysics Data System (ADS)

    Wang, Shuxiao; Wei, Wei; Li, Du; Aunan, Kristin; Hao, Jiming

    2010-11-01

    Several types of fuels, including coal, fuel wood, and biogas, are commonly used for cooking and heating in Chinese rural households, resulting in indoor air pollution and causing severe health impacts. In this paper, we report a study monitoring multiple pollutants including PM 10, PM 2.5, CO, CO 2, and volatile organic compounds (VOCs) from fuel combustion at households in Guizhou province of China. The results showed that most pollutants exhibited large variability for different type of fuels except for CO 2. Among these fuels, wood combustion caused the most serious indoor air pollution, with the highest concentrations of particulate matters (218˜417 μg m -3 for PM 10 and 201˜304 μg m -3 for PM 2.5), and higher concentrations of CO (10.8 ± 0.8 mg m -3) and TVOC (about 466.7 ± 337.9 μg m -3). Coal combustion also resulted in higher concentrations of particulate matters (220˜250 μg m -3 for PM 10 and 170˜200 μg m -3 for PM 2.5), but different levels for CO (respectively 14.5 ± 3.7 mg m -3 for combustion in brick stove and 5.5 ± 0.7 mg m -3 for combustion in metal stove) and TVOC (170 mg m -3 for combustion in brick stove and 700 mg m -3 for combustion in metal stove). Biogas was the cleanest fuel, which brought about the similar levels of various pollutants with the indoor case of non-combustion, and worth being promoted in more areas. Analysis of the chemical profiles of PM 2.5 indicated that OC and EC were dominant components for all fuels, with the proportions of 30˜48%. A high fraction of SO 42- (31˜34%) was detected for coal combustion. The cumulative percentages of these chemical species were within the range of 0.7˜1.3, which was acceptable for the assessment of mass balance.

  15. The Impact of Carrot Enriched in Iodine through Soil Fertilization on Iodine Concentration and Selected Biochemical Parameters in Wistar Rats.

    PubMed

    Piątkowska, Ewa; Kopeć, Aneta; Bieżanowska-Kopeć, Renata; Pysz, Mirosław; Kapusta-Duch, Joanna; Koronowicz, Aneta Agnieszka; Smoleń, Sylwester; Skoczylas, Łukasz; Ledwożyw-Smoleń, Iwona; Rakoczy, Roksana; Maślak, Edyta

    2016-01-01

    Iodine is one of the trace elements which are essential for mammalian life. The major objective of iodine biofortification of plants is to obtain food rich in this trace element, which may increase its consumption by various populations. Additionally, it may reduce the risk of iodine deficiency diseases. In this research for the first time we have assessed the bioavailability of iodine from raw or cooked carrot biofortified with this trace element on iodine concentration in selected tissues and various biochemical parameters as well as mRNA expression of some genes involved in iodine metabolism in Wistar rats. Statistically, a significantly higher iodine level was determined in urine, faeces and selected tissues of rats fed a diet containing biofortified raw carrot as compared to a diet without iodine and a diet containing control cooked carrot. Biofortified raw carrot significantly increased triiodothyronine concentration as compared to animals from other experimental groups. The highest thyroid stimulating hormone level was determined in rats fed control cooked carrots. mRNA expression of selected genes was affected by different dietary treatment in rats' hearts. Biofortified raw and cooked carrot could be taken into account as a potential source of iodine in daily diets to prevent iodine deficiency in various populations. PMID:27043135

  16. The Impact of Carrot Enriched in Iodine through Soil Fertilization on Iodine Concentration and Selected Biochemical Parameters in Wistar Rats

    PubMed Central

    Piątkowska, Ewa; Kopeć, Aneta; Bieżanowska-Kopeć, Renata; Pysz, Mirosław; Kapusta-Duch, Joanna; Koronowicz, Aneta Agnieszka; Smoleń, Sylwester; Skoczylas, Łukasz; Ledwożyw-Smoleń, Iwona; Rakoczy, Roksana; Maślak, Edyta

    2016-01-01

    Iodine is one of the trace elements which are essential for mammalian life. The major objective of iodine biofortification of plants is to obtain food rich in this trace element, which may increase its consumption by various populations. Additionally, it may reduce the risk of iodine deficiency diseases. In this research for the first time we have assessed the bioavailability of iodine from raw or cooked carrot biofortified with this trace element on iodine concentration in selected tissues and various biochemical parameters as well as mRNA expression of some genes involved in iodine metabolism in Wistar rats. Statistically, a significantly higher iodine level was determined in urine, faeces and selected tissues of rats fed a diet containing biofortified raw carrot as compared to a diet without iodine and a diet containing control cooked carrot. Biofortified raw carrot significantly increased triiodothyronine concentration as compared to animals from other experimental groups. The highest thyroid stimulating hormone level was determined in rats fed control cooked carrots. mRNA expression of selected genes was affected by different dietary treatment in rats’ hearts. Biofortified raw and cooked carrot could be taken into account as a potential source of iodine in daily diets to prevent iodine deficiency in various populations. PMID:27043135

  17. The Impact of Carrot Enriched in Iodine through Soil Fertilization on Iodine Concentration and Selected Biochemical Parameters in Wistar Rats.

    PubMed

    Piątkowska, Ewa; Kopeć, Aneta; Bieżanowska-Kopeć, Renata; Pysz, Mirosław; Kapusta-Duch, Joanna; Koronowicz, Aneta Agnieszka; Smoleń, Sylwester; Skoczylas, Łukasz; Ledwożyw-Smoleń, Iwona; Rakoczy, Roksana; Maślak, Edyta

    2016-01-01

    Iodine is one of the trace elements which are essential for mammalian life. The major objective of iodine biofortification of plants is to obtain food rich in this trace element, which may increase its consumption by various populations. Additionally, it may reduce the risk of iodine deficiency diseases. In this research for the first time we have assessed the bioavailability of iodine from raw or cooked carrot biofortified with this trace element on iodine concentration in selected tissues and various biochemical parameters as well as mRNA expression of some genes involved in iodine metabolism in Wistar rats. Statistically, a significantly higher iodine level was determined in urine, faeces and selected tissues of rats fed a diet containing biofortified raw carrot as compared to a diet without iodine and a diet containing control cooked carrot. Biofortified raw carrot significantly increased triiodothyronine concentration as compared to animals from other experimental groups. The highest thyroid stimulating hormone level was determined in rats fed control cooked carrots. mRNA expression of selected genes was affected by different dietary treatment in rats' hearts. Biofortified raw and cooked carrot could be taken into account as a potential source of iodine in daily diets to prevent iodine deficiency in various populations.

  18. Has the Impact of Rising CO2 on Plants been Exaggerated by Meta-Analysis of Free Air CO2 Enrichment Studies?

    PubMed

    Haworth, Matthew; Hoshika, Yasutomo; Killi, Dilek

    2016-01-01

    Meta-analysis is extensively used to synthesize the results of free air CO2 enrichment (FACE) studies to produce an average effect size, which is then used to model likely plant response to rising [CO2]. The efficacy of meta-analysis is reliant upon the use of data that characterizes the range of responses to a given factor. Previous meta-analyses of the effect of FACE on plants have not incorporated the potential impact of reporting bias in skewing data. By replicating the methodology of these meta-analytic studies, we demonstrate that meta-analysis of FACE has likely exaggerated the effect size of elevated [CO2] on plants by 20 to 40%; having significant implications for predictions of food security and vegetation response to climate change. Incorporation of the impact of reporting bias did not affect the significance or the direction of the [CO2] effect. PMID:27536310

  19. Has the Impact of Rising CO2 on Plants been Exaggerated by Meta-Analysis of Free Air CO2 Enrichment Studies?

    PubMed

    Haworth, Matthew; Hoshika, Yasutomo; Killi, Dilek

    2016-01-01

    Meta-analysis is extensively used to synthesize the results of free air CO2 enrichment (FACE) studies to produce an average effect size, which is then used to model likely plant response to rising [CO2]. The efficacy of meta-analysis is reliant upon the use of data that characterizes the range of responses to a given factor. Previous meta-analyses of the effect of FACE on plants have not incorporated the potential impact of reporting bias in skewing data. By replicating the methodology of these meta-analytic studies, we demonstrate that meta-analysis of FACE has likely exaggerated the effect size of elevated [CO2] on plants by 20 to 40%; having significant implications for predictions of food security and vegetation response to climate change. Incorporation of the impact of reporting bias did not affect the significance or the direction of the [CO2] effect.

  20. Concentrations of legacy and emerging flame retardants in air and soil on a transect in the UK West Midlands.

    PubMed

    Drage, Daniel S; Newton, Seth; de Wit, Cynthia A; Harrad, Stuart

    2016-04-01

    Passive air samples were collected monthly for 6 months from 8 sites along a transect of Birmingham, United Kingdom between June 2012 and January 2013. Soil samples were collected once at each site. Average concentrations of BDE-209, ΣPBDEs17:183 and ΣPBDEs in ambient air were 150, 49, and 180 pg m(-3), respectively. Atmospheric concentrations of PBDEs were negatively correlated with distance from the city centre, exhibiting an "urban pulse". The average ΣHBCDD air concentration was 100 pg m(-3), however concentrations were not correlated with distance from the city centre. Several emerging flame retardants (EFRs) were identified in air and/or soil samples: 2,3,4,5-tetrabromo-bis(2-ethylhexyl) phthalate (BEH-TEBP), 1,2-dibromo-4-(1,2 dibromoethyl)cyclohexane (TBECH or DBE-DBCH), allyl 2,4,6-tribromophenyl ether (ATE), 2-bromoallyl 2,4,6-tribromophenyl ether (BATE), decabromodiphenyl ethane (DBDPE), and dechlorane plus (DP or DDC-CO). Average concentrations of BDE-209, ΣPBDEs17:183 and ΣPBDEs in soil were 11, 3.6, and 15 ng g(-1) soil organic matter. PBDE concentrations in soil were higher at sites closest to the city centre, however correlations with distance from the city centre were not significant. BDEs-47 and -99 contributed more to ΣPBDEs in soil samples than air samples, but in both, the predominant congener was BDE-209. BATE was more abundant in air than soil but ATE was abundant in soil but not air. PMID:26807939

  1. Effects of air current speed, light intensity and co2 concentration on photosynthesis and transpiration of plant leaves

    NASA Astrophysics Data System (ADS)

    Kitaya, Y.; Tsuruyama, J.; Shibuya, T.; Kiyota, M.

    To obtain basic data for adequate air circulation to promote gas exchange and growth of plants in closed plant culture modules in bioregenerative life support systems in space, the effects of air current speeds less than 0.8 m s-1 on transpiration (Tr) and net photosynthetic rates (Pn) of sweetpotato and barley leaves were determined using a leaf chamber method under different photosynthetic photon flux densities (PPFDs) and CO_2 concentrations. The air current speed inside the leaf chamber was controlled by controlling the input voltages for an air circulation fan. The leaf surface boundary layer resistance was determined by the evaporation rate of wet paper and the water vapor pressure difference between the paper and surrounding air in the leaf chamber. The Tr and Pn of leaves rapidly increased as the air current speed increased from 0.01 to 0.1 m s-1 and gradually increased from 0.1 to 0.8 m s-1. These changes are correspondent to the change of the leaf surface boundary layer resistance. The depression of Tr by low air current speeds was greater than that of Pn. Tr and Pn decreased by 0.5 and 0.7 times, respectively, as the air current speed decreased from 0.8 to 0.01 m s-1. The depressions of Tr and Pn by low air current speeds were most notable at PPFDs of 500 and 250 μmol m-2 s-1, respectively. The air current speeds affected Tr and Pn at a CO_2 concentration of 700 μmol mol-1 as well as at 400 μmol mol-1. The results confirmed the importance of controlling air movement for enhancing Tr and Pn under the relatively high PPFD and elevated CO_2 levels likely in plant culture systems in space.

  2. A layered magnetic iron/iron oxide nanoscavenger for the analytical enrichment of ng-L(-1) concentration levels of heavy metals from water.

    PubMed

    Karatapanis, Andreas E; Petrakis, Dimitrios E; Stalikas, Constantine D

    2012-05-13

    Magnetically driven separation techniques have received considerable attention in recent decade because of their great potential application. In this study, we investigate the application of an unmodified layered magnetic Fe/Fe(2)O(3) nanoscavenger for the analytical enrichment and determination of sub-parts per billion concentrations of Cd(II), Pb(II), Ni(II), Cr(VI) and As(V) from water samples. The synthesized nanoscavenger was characterized by BET, TGA, XRD and IR and the parameters influencing the extraction and recovery of the preconcentration process were assessed by atomic absorption spectrometry. The possible mechanism of the enrichment of heavy metals on Fe/Fe(2)O(3) was proposed, which involved the dominant adsorption and reduction. The nanoscale size offers large surface area and high reactivity of sorption and reduction reactions. The obtained limits of detection for the metals studied were in the range of 20-125 ng L(-1) and the applicability of the nanomaterial was verified using a real sample matrix. The method is environmentally friendly as only 15 mg of nanoscavenger are used, no organic solvent is required for the extraction and the experiment is performed without the need for filtration or preparation of packed preconcentration columns.

  3. Effect of Nitrite and Nitrate Concentrations on the Performance of AFB-MFC Enriched with High-Strength Synthetic Wastewater.

    PubMed

    Huang, Jian-Sheng; Yang, Ping; Li, Chong-Ming; Guo, Yong; Lai, Bo; Wang, Ye; Feng, Li; Zhang, Yun

    2015-01-01

    In order to study the effect of nitrite and nitrate on the performance of microbial fuel cell, a system combining an anaerobic fluidized bed (AFB) and a microbial fuel cell (MFC) was employed for high-strength nitrogen-containing synthetic wastewater treatment. Before this study, the AFB-MFC had been used to treat high-strength organic wastewater for about one year in a continuous flow mode. The results showed that when the concentrations of nitrite nitrogen and nitrate nitrogen were increased from 1700 mg/L to 4045 mg/L and 545 mg/L to 1427 mg/L, respectively, the nitrite nitrogen and nitrate nitrogen removal efficiencies were both above 99%; the COD removal efficiency went up from 60.00% to 88.95%; the voltage was about 375 ± 15 mV while the power density was at 70 ± 5 mW/m(2). However, when the concentrations of nitrite nitrogen and nitrate nitrogen were above 4045 mg/L and 1427 mg/L, respectively, the removal of nitrite nitrogen, nitrate nitrogen, COD, voltage, and power density were decreased to be 86%, 88%, 77%, 180 mV, and 17 mW/m(2) when nitrite nitrogen and nitrate nitrogen were increased to 4265 mg/L and 1661 mg/L. In addition, the composition of biogas generated in the anode chamber was analyzed by a gas chromatograph. Nitrogen gas, methane, and carbon dioxide were obtained. The results indicated that denitrification happened in anode chamber. PMID:26495144

  4. Effect of Nitrite and Nitrate Concentrations on the Performance of AFB-MFC Enriched with High-Strength Synthetic Wastewater

    PubMed Central

    Huang, Jian-sheng; Yang, Ping; Li, Chong-ming; Guo, Yong; Lai, Bo; Wang, Ye; Feng, Li; Zhang, Yun

    2015-01-01

    In order to study the effect of nitrite and nitrate on the performance of microbial fuel cell, a system combining an anaerobic fluidized bed (AFB) and a microbial fuel cell (MFC) was employed for high-strength nitrogen-containing synthetic wastewater treatment. Before this study, the AFB-MFC had been used to treat high-strength organic wastewater for about one year in a continuous flow mode. The results showed that when the concentrations of nitrite nitrogen and nitrate nitrogen were increased from 1700 mg/L to 4045 mg/L and 545 mg/L to 1427 mg/L, respectively, the nitrite nitrogen and nitrate nitrogen removal efficiencies were both above 99%; the COD removal efficiency went up from 60.00% to 88.95%; the voltage was about 375 ± 15 mV while the power density was at 70 ± 5 mW/m2. However, when the concentrations of nitrite nitrogen and nitrate nitrogen were above 4045 mg/L and 1427 mg/L, respectively, the removal of nitrite nitrogen, nitrate nitrogen, COD, voltage, and power density were decreased to be 86%, 88%, 77%, 180 mV, and 17 mW/m2 when nitrite nitrogen and nitrate nitrogen were increased to 4265 mg/L and 1661 mg/L. In addition, the composition of biogas generated in the anode chamber was analyzed by a gas chromatograph. Nitrogen gas, methane, and carbon dioxide were obtained. The results indicated that denitrification happened in anode chamber. PMID:26495144

  5. Reduced-Rank Spatio-Temporal Modeling of Air Pollution Concentrations in the Multi-Ethnic Study of Atherosclerosis and Air Pollution1

    PubMed Central

    Olives, Casey; Sheppard, Lianne; Lindström, Johan; Sampson, Paul D.; Kaufman, Joel D.; Szpiro, Adam A.

    2016-01-01

    There is growing evidence in the epidemiologic literature of the relationship between air pollution and adverse health outcomes. Prediction of individual air pollution exposure in the Environmental Protection Agency (EPA) funded Multi-Ethnic Study of Atheroscelerosis and Air Pollution (MESA Air) study relies on a flexible spatio-temporal prediction model that integrates land-use regression with kriging to account for spatial dependence in pollutant concentrations. Temporal variability is captured using temporal trends estimated via modified singular value decomposition and temporally varying spatial residuals. This model utilizes monitoring data from existing regulatory networks and supplementary MESA Air monitoring data to predict concentrations for individual cohort members. In general, spatio-temporal models are limited in their efficacy for large data sets due to computational intractability. We develop reduced-rank versions of the MESA Air spatio-temporal model. To do so, we apply low-rank kriging to account for spatial variation in the mean process and discuss the limitations of this approach. As an alternative, we represent spatial variation using thin plate regression splines. We compare the performance of the outlined models using EPA and MESA Air monitoring data for predicting concentrations of oxides of nitrogen (NOx)—a pollutant of primary interest in MESA Air—in the Los Angeles metropolitan area via cross-validated R2. Our findings suggest that use of reduced-rank models can improve computational efficiency in certain cases. Low-rank kriging and thin plate regression splines were competitive across the formulations considered, although TPRS appeared to be more robust in some settings. PMID:27014398

  6. Concentration, temperature, and density in a hydrogen-air flame by excimer-induced Raman scattering

    NASA Technical Reports Server (NTRS)

    Wehrmeyer, Joseph A.; Bowling, John M.; Pitz, Robert W.

    1988-01-01

    Single-pulse, vibrational Raman scattering (VRS) is an attractive laser diagnostic for the study of supersonic hydrogen-air combustion. The VRS technique gives a complete thermodynamic description of the gas mixture at a point in the reacting flow. Single-pulse, vibrational Raman scattering can simultaneously provide independent measurements of density, temperature, and concentration of each major species (H2, H2O, O2 and N2) in a hydrogen/air turbulent combustor. Also the pressure can be calculated using the ideal gas law. However, single-pulse VRS systems in current use for measurement of turbulent combustion have a number of shortcomings when applied to supersonic flows: (1) slow repetition rate (1 to 5 Hz), (2) poor spatial resolution (0.5x0.3x0.3 cu mm), and (3) marginal time resolution. Most of these shortcomings are due to the use of visible wavelength flash-lamp pumped dye lasers. The advent of UV excimer laser allows the possibility of dramatic improvements in the single-pulse, vibrational Raman scattering. The excimer based VRS probe will greatly improve repetition rate (100 to 500 Hz), spatial resolution (0.1x0.1x0.1 cu mm) and time resolution (30ns). These improvements result from the lower divergence of the UV excimer, higher repetition rate, and the increased Raman cross-sections (15 to 20 times higher) at ultra-violet (UV) wavelengths. With this increased capability, single-pulse vibrational Raman scattering promises to be an ideal non-intrusive probe for the study of hypersonic propulsion flows.

  7. Distinct patterns in the diurnal and seasonal variability in four components of soil respiration in a temperate forest under free-air CO2 enrichment

    NASA Astrophysics Data System (ADS)

    Taneva, L.; Gonzalez-Meler, M. A.

    2011-03-01

    Soil respiration (RS) is a major flux in the global carbon (C) cycle and its responses to changing environmental conditions may exert a strong control on the residence time of C in terrestrial ecosystems and in turn influence the atmospheric concentration of greenhouse gases. Soil respiration consists of several components returning C of different nature and age to the atmosphere, with root/rhizosphere respiration often assumed to be the dominant and variable one. Rates of RS vary greatly in time and space and the mechanisms underlying this temporal variability, or the RS components responsible for it, are poorly understood. It is often assumed the Rs and its components are under abiotic control at almost all time scales. In this study, we used the ecosystem 13C tracer at the Duke Forest Free Air CO2 Enrichment site to separate forest RS into four components: root/rhizosphere respiration (RR), litter decomposition (RL), and decomposition of soil organic matter (SOM) of two age classes - up to 8 years old and SOM older than 8 years. We then examined and found that diurnal and seasonal variability in the components of Rs occurred at different magnitudes and directions than total RS. Soil respiration was generally dominated by RSOM during the growing season (44% of daytime RS), especially at night. The contribution of heterotrophic respiration (RSOM and RL) to RS was not constant during the growing season, indicating that the seasonal variability seen in RR alone cannot explain the seasonal variability in RS. Although there was no diurnal variability in RS, there were significant compensatory differences in the contribution of individual RS components to daytime and nighttime rates. The average contribution of RSOM to RS was greater at night (54%) than during the day (44%) whereas the average contribution of RR to total RS was ~30% during the day and ~34% during the night. In contrast, RL constituted 26% of RS during the day and only 12% at night. Interestingly, the

  8. Comparison of indoor and outdoor concentrations of CO at a public school. Evaluation of an indoor air quality model

    NASA Astrophysics Data System (ADS)

    Chaloulakou, A.; Mavroidis, I.

    A field study was carried out to investigate the internal and external carbon monoxide (CO) concentration levels of a public school building in Athens, Greece. Simultaneous measurements of indoor and outdoor CO concentrations were conducted using a non-dispersive infrared analyzer. Measurements of mean hourly CO concentrations inside and outside the sampling room were conducted on a 24-h basis for 13 consecutive days during May and June 1999 and for 14 consecutive days during December 1999. The aim of the study was to investigate the attenuation pattern of external pollution levels within the building. The diurnal concentration variations reported for different days during the week show that indoor CO concentrations are in general lower than the respective outdoor levels, and that the morning peaks of indoor concentrations show a delay of 1 h or less compared to the morning peaks of outdoor concentrations. The measured indoor to outdoor concentration ratios show a seasonal variation. An indoor air quality model for the prediction of indoor concentration levels developed by Hayes (J. Air Pollut. Control Assoc. 39 (11) (1989) 1453; J. Air Waste Manage. Assoc. 41 (2) (1991) 161) is coded as a computer program and evaluated using the experimental data. The model results are in good agreement with the indoor concentration measurements, although in some cases the model cannot respond adequately to sharp outdoor concentration changes. The ratio between measured and predicted daily maximum indoor concentration ranges between 0.88 and 1.23. The regression curve between predicted by the model and measured hourly indoor concentrations, for a continuous period of 96 h, has a slope of 0.64 and a coefficient of determination ( R2) of 0.69.

  9. Leaf and canopy responses to elevated CO{sub 2} in a pine plantation under free-air CO{sub 2} enrichment (FACE)

    SciTech Connect

    Ellsworth, D.S.; Oren, R.; Hendrey, G. |

    1995-09-01

    Free-air CO{sub 2} enrichment (FACE) was used to expose an intact lobolly pine forest ecosystem to elevated CO{sub 2}. Leaf conductance and canopy water flux measurements along with A{sub net}-C{sub i} curves were used to evaluate physiological responses of the dominant trees to elevated CO{sub 2}. CO{sub 2}-exposed trees showed minor (<7%) but significant reductions in sap flux density compared to trees under ambient CO{sub 2} conditions, but only when air saturation vapor pressure deficit (VPD) was low. Short-term (minutes) direct stomatal responses to elevated CO{sub 2} were also relatively weak. We observed no evidence of adjustments in stomatal conductance in current-year foliage grown under elevated CO{sub 2} for 80 days compared to foliage grown under ambient CO{sub 2}. Leaf net photosynthetic rate at 550 {mu}mol mol{sup {minus}1} CO{sub 2} was enhanced by more than 50% compared to the rate at ambient CO{sub 2}(350 {mu}mol mol{sup {minus}1}). Thus, leaf water-use-efficiency of loblolly pine at elevated CO{sub 2} was enhanced primarily by direct responses of photosynthesis to CO{sub 2} and was not mediated by stomata.

  10. Polydextrose enrichment of infant formula demonstrates prebiotic characteristics by altering intestinal microbiota, organic acid concentrations, and cytokine expression in suckling piglets.

    PubMed

    Herfel, Tina M; Jacobi, Sheila K; Lin, Xi; Fellner, Vivek; Walker, D Carey; Jouni, Zeina E; Odle, Jack

    2011-12-01

    Oligosaccharides, the 3rd-most abundant component in human milk, are virtually absent from infant formulas and from the cow milk on which most are based. In breast-fed infants, human milk oligosaccharides (HMO) act as both receptor analogs, interfering with pathogen adhesion, and as prebiotics, stimulating the growth of certain commensal bacteria (e.g. bifidobacteria) and supporting the innate immunity. To further align the functional properties of infant formula with those of human milk, polydextrose (PDX) is proposed as a substitute for HMO. To determine the prebiotic functionality of PDX, 1-d-old pigs were fed a cow milk-based formula supplemented with increasing concentrations of PDX (0, 1.7, 4.3, 8.5, or 17 g/L) for 18 d (n = 13). Additional reference groups included pigs sampled at d 0 and sow-reared pigs sampled at d 18 (n = 12). Ileal Lactobacilli CFU, but not Bifidobacteria, increased linearly with increasing PDX (P = 0.02). The propionic acid concentration in digesta linearly increased with the PDX level (P = 0.045) and lactic acid increased linearly by 5-fold with increasing PDX (P = 0.001). Accordingly, digesta pH decreased linearly (P < 0.05) as PDX increased, with a maximal reduction approaching 0.5 pH units in pigs fed 17 g/L. Expression of TNFα, IL-1β, and IL-8 showed a negative quadratic pattern in response to PDX supplementation, declining at intermediate concentrations and rebounding at higher concentrations of PDX. In summary, PDX enrichment of infant formula resulted in a prebiotic effect by increasing ileal lactobacilli and propionic and lactic acid concentrations and decreasing pH with associated alterations in ileal cytokine expression.

  11. Liquid products from oxidative thermal treatment of oil sludge with different oxygen concentrations of air.

    PubMed

    Shie, J L; Chang, C Y; Lin, J P; Le, D J; Wu, C H

    2001-01-01

    Oxidative thermal treatment of oil sludge with different oxygen concentrations of air by using a dynamic thermogravimetric (TG) reaction system is investigated. The experimental conditions employed are: gas flow rate of 50 cm3/min (value at 298 K) for 300 mg dry waste, a constant heating rate of 5.2 K/min, the oxygen concentrations in air of 1.09, 8.62 and 20.95 vol. % O2, and the temperature (T) range of 378-873 K. From the experimental results, the residual mass fractions (M) are about 78.95, 28.49, 8.77 and 4.13 wt. % at the oxidative T of 563, 713, 763 and 873 K for the case with 20.95 vol. % O2, respectively. The values of M with 8.62 and 1.09 vol. % O2 at T of 873 K are 4.87 and 9.44 wt. %, respectively. The distillation characteristics of the oil portion of liquid products (condensates of gas at 298 K) from the oxidative thermal treatment of oil sludge with 20.95 vol. % O2 at T of 378-873 K is close to those of commercial gasoline. Nevertheless, the liquid product contains a large amount of water. The distillation characteristics of the oil portions of liquid products with 8.62 and 1.09 vol. % O2 at T of 378-873 K are close to those of diesel and fuel oils, respectively. The oil quality with 8.62 vol. % O2 is better than that with 1.09 vol. % O2. However, the liquid product with 8.62 vol. % O2 still contains a large amount of water; nonetheless, that with 1.09 vol. % O2 is with negligible water. Compared with the oil product of nitrogen pyrolysis, the oil quality with 1.09 vol. % O2 is better. Certainly, low oxygen conditions (i.e. 1.09 vol. % O2) not only accelerate the thermal reaction of oil sludge, but also at the same time avoid or reduce the production of water. Further, from the analysis of benzene (B), ethylbenzene (E), toluene (T) and iso-xylene (X) concentrations of the oil portion of liquid products, the BETX concentrations of oil with 20.95 vol. % O2 are higher than those with 8.62 and 1.09 vol. % O2. The yields of liquid products with 20.95, 8

  12. Influences of ambient air PM₂.₅ concentration and meteorological condition on the indoor PM₂.₅ concentrations in a residential apartment in Beijing using a new approach.

    PubMed

    Han, Yang; Qi, Meng; Chen, Yilin; Shen, Huizhong; Liu, Jing; Huang, Ye; Chen, Han; Liu, Wenxin; Wang, Xilong; Liu, Junfeng; Xing, Baoshan; Tao, Shu

    2015-10-01

    PM2.5 concentrations in a typical residential apartment in Beijing and immediately outside of the building were measured simultaneously during heating and non-heating periods. The objective was to quantitatively explore the relationship between indoor and outdoor PM2.5 concentrations. A statistical method for predicting indoor PM2.5 concentrations was proposed. Ambient PM2.5 concentrations were strongly affected by meteorological conditions, especially wind directions. A bimodal distribution was identified during the heating season due to the frequent and rapid transition between severe pollution events and clean days. Indoor PM2.5 concentrations were significantly correlated with outdoor PM2.5 concentrations but with 1-2 h delay, and the differences can be explained by ambient meteorological features, such as temperature, humidity, and wind direction. These results indicate the potential to incorporate indoor exposure features to the regional air quality model framework and to more accurately estimate the epidemiological relationship between human mortality and air pollution exposure.

  13. Sulfate concentrations as an indicator of ambient particulate matter air pollution for health risk evaluations.

    PubMed

    Lippmann, M; Thurston, G D

    1996-01-01

    Retrospective population studies that have compared regression coefficients for mortality and morbidity for sulfate (SO4(2-), fine particles (PM2.5; aerodynamic diameter < 2.5 microns), thoracic particles (PM10; aerodynamic diameter < 10 microns), and total suspended particulates (TSP; undefined and variable upper cut-size) generally have found SO4(2-) concentrations to be correlated with effects as well as or better than PM2.5. In addition, both SO4(2-) and PM2.5 have yielded somewhat stronger associations with adverse health effects than PM10, and much stronger associations than TSP. Sulfate has advantages over PM2.5 for retrospective epidemiology, at least in the United States, because considerably more data on sulfate have been collected in recent decades, and there is a broader epidemiological database in the literature for comparison to other studies. While SO4(2-), per se, is an unlikely causal factor for mortality or morbidity, it often is correlated closely with variations in the strong acid component of ambient particulate matter (H+) and PM2.5 concentrations (especially in summer), which are more likely causal factors. A detailed analysis of the SO4(2-) epidemiological database is presented in this paper. In addition, drawing on our substantial archives of SO4(2-) and H+ data, we show that SO4(2-) and H+ correlate, both spatially and over time, in the eastern United States. We demonstrate the utility of SO4(2-) as a useful surrogate for ambient PM2.5 and H+ in epidemiological studies and as an index of PM exposure in ambient air quality guidelines and standards.

  14. Assessing the impact of the forthcoming decrease in diesel exhaust particulate matter emissions on air quality: implications for black carbon concentrations in ambient air

    NASA Astrophysics Data System (ADS)

    González, Y.; Rodríguez, S.; Cuevas, E.; Ramos, R.; Abreu-Afonso, J.; Baldasano, J. M.

    2009-04-01

    Forthcoming regulations (e.g. EURO 5 and EURO 6) are planned to reduce particulate matter emissions (PM) in the exhaust of forthcoming vehicles. In this study we assess the impact of such reduction in the diesel PM exhaust emissions on the urban ambient air PM concentrations. This has been done by studying the relationship between black carbon (BC) and carbon monoxide (CO) in urban ambient air and in the exhaust of current and forthcoming vehicles. The slope of the BC-vs-CO linear relationship is mainly affected by the percentage (%) of diesel automobiles in the urban vehicles fleet. This slope is a better indicator of the diesel PM emissions than bulk BC concentrations in urban ambient air. BC-vs-CO slopes within the range 1-3 and 7-14 ngBC/µgCO are typically observed in urban areas with low (<25%) and high (≥50%) proportions of diesel-fuel consumption for on road transportation, respectively. The entry into force of forthcoming regulations will decrease the BC-vs-CO slope in urban ambient air from about 10 to 5 ngBC/µgCO in the next decade, according to calculations based on the current data on diesel vehicles in urban fleets in Spanish cities. However, this will not necessary prompt a significant decrease in the urban BC concentrations if road traffic volume follows the increasing trend of the last decade. The results of this study shows that the analysis of the BC-vs-CO slope trend in ambient air is an useful tool for understanding the involvement "of the changes in the vehicle exhaust emissions rates" and "of the changes in the road traffic volume" in the BC and PMx trends in urban ambient air.

  15. BTEX air concentrations and self-reported common health problems in gasoline sellers from Cotonou, Benin.

    PubMed

    Tohon, Honesty Gbèdolo; Fayomi, Benjamin; Valcke, Mathieu; Coppieters, Yves; Bouland, Catherine

    2015-01-01

    To examine the relation between BTEX exposure levels and common self-reported health problems in 140 gasoline sellers in Cotonou, Benin, a questionnaire documenting their socioeconomic status and their health problems was used, whereas 18 of them went through semi-directed qualitative individual interviews and 17 had air samples taken on their workplace for BTEX analysis. Median concentrations for BTEX were significantly lower on official (range of medians: 54-207 μg/m³, n = 9) vs unofficial (148-1449 μg/m³, n = 8) gasoline-selling sites (p < 0.05). Self-reported health problems were less frequently reported in sellers from unofficial vs official selling sites (p < 0.05), because, as suggested by the semi-directed interviews, of their fear of losing their important, but illegal, source of income. Concluding, this study has combined quantitative and qualitative methodological approaches to account for the complex socioeconomic and environmental conditions of the investigated sellers, leading to their, in some cases, preoccupying BTEX exposure.

  16. Radical Concentrations and Prompt NO Formation in Hydrocarbon-Air Premixed Flames

    NASA Astrophysics Data System (ADS)

    Matusi, Yasuji; Yuuki, Akimasa

    1985-05-01

    Hydroxyl radical concentrations in laminar, premixed CH4-air flat-flames were measured by a conventional absorption method in the flame temperature range T{=}2200-1700 K. The OH mole fractions in the reaction zone POH were found to be insensitive to the flame temperature and the maximum POH to be about 6× 10-3 at T{=}2000 K in a stoichiometric flame. The rate constant for the prompt NO formation, CH+N2→HCN+N\\dashrightarrow2NO (4), is modified as k4{=}1.2× 1012\\exp (-13600/RT) by the relation between the amount of prompt NO and the saturation ion current Is. It is also shown from the measurements of NOx, unburnt hydrocarbons H.C., and Is, that the chemical kinetics are not significantly influenced by the flame temperature, and NO emission is reduced by reactions among NO, H.C., and N-containing intermediate species in low-temperature flames, even in stoichiometric and fuel-lean mixtures.

  17. [Volatile organic compounds concentrations and sources inside new air-conditioned bus].

    PubMed

    You, Ke-Wei; Ge, Yun-Shan; Qian, Yi-Xin; Liu, Wei; Feng, Bo; Zhang, Yan-Ni; Ning, Zhan-Wu; Hu, Bin; Zhao, Shou-Tang

    2008-05-01

    The distributing profile and concentration level inside new air-conditioned buses with 53 seats have been determined using the method of thermal desorption-capillary GC/MS under vehicle static conditions. Compounds were identified from their mass spectral data by using US National Institute of Standards and Technology (NIST02). The total numbers of identified components were 33 inside buses, including alkenes (15,45.4%), aromatic compounds (9,27.3%), alcohols (4,12.1%), ketones (3,9.1%) and esters (2,6.1%), especially in the range of C6-C10. The top 5 compounds measured inside buses were decane (8.01 mg/m3), 3-methylhexane (7.10 mg/m3), heptane (5.10 mg/m3), isoheptane (4.20 mg/m3) and 1-Methyl-3-ethylbenzene (3.56 mg/m3), and total volatile organic compounds (TVOC) > 52.5 mg/m3. The main sources of in-vehicle hydrocarbons and aromatic compounds comes from cabin components and interior trim materials (e.g., sealants, carpets, adhesives, paints, leather, plastics, PU foam and PE foam) that may retain certain VOCs during manufacturing, and/or emit these compounds over an extended period of time from off-gassing, aging-related breakdown products, heating/cooling and so on.

  18. Effect of the implosion and demolition of a hospital building on the concentration of fungi in the air.

    PubMed

    Barreiros, Gloria; Akiti, Tiyomi; Magalhães, Ana Cristina Gouveia; Nouér, Simone A; Nucci, Marcio

    2015-12-01

    Building renovations increase the concentration of Aspergillus conidia in the air. In 2010, one wing of the hospital building was imploded due to structural problems. To evaluate the impact of building implosion on the concentration of fungi in the air, the demolition was performed in two phases: mechanical demolition of 30 m of the building, followed by implosion of the wing. Patients at high risk for aspergillosis were placed in protected wards. Air sampling was performed during mechanical demolition, on the day of implosion and after implosion. Total and specific fungal concentrations were compared in the different areas and periods of sampling, using the anova test. The incidence of IA in the year before and after implosion was calculated. The mean concentration of Aspergillus increased during mechanical demolition and on the day of implosion. However, in the most protected areas, there was no significant difference in the concentration of fungi. The incidence of invasive aspergillosis (cases per 1000 admissions) was 0.9 in the 12 months before, 0.4 during, and 0.5 in the 12 months after mechanical demolition (P > 0.05). Continuous monitoring of the quality of air and effective infection control measures are important to minimize the impact of building demolition. PMID:26449634

  19. Indoor air quality in the Karns research houses: baseline measurements and impact of indoor environmental parameters on formaldehyde concentrations

    SciTech Connect

    Matthews, T. G.; Fung, K. W.; Tromberg, B. J.; Hawthorne, A. R.

    1985-12-01

    Baseline indoor air quality measurements, a nine-month radon study, and an environmental parameters study examining the impact of indoor temperature (T) and relative humidity (RH) levels on formaldehyde (CH2O) concentrations have been performed in three unoccupied research homes located in Karns, Tennessee. Inter-house comparison measurements of (1) CH2O concentration, (2) CH20 emission rates from primary CH20 emission sources, (3) radon and radon daughter concentrations, and (4) air exchange rates indicate that the three homes are similar. The results of the nine-month radon study indicate indoor concentrations consistently below the EPA recommended level of 4 pCi/L. Evidence was found that crawl-space concentrations may be reduced using heat pump systems whose outdoor units circulate fresh air through the crawl-spaoe. The modeled results of the environmental parameters study indicate approximate fourfold increases in CH20 concentrations from 0.07 to 0.27 ppm for seasonal T and RH conditions of 20°C, 30% RH and 29°C, 80% RH, respectively. Evaluation of these environmental parameters study data with steady-state CH2O concentration models developed from laboratory studies of the environmental dependence of CH2O emissions from particleboard underlayment indicate good correlations between the laboratory and field studies.

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

    EPA Science Inventory

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

  1. VERSATILE AEROSOL CONCENTRATION ENRICHMENT SYSTEM (VACES) FOR SIMULTANEOUS IN-VIVO AND IN-VITRO EVALUATION OF TOXIC EFFECTS OF ULTRAFINE, FINE, AND COARSE AMBIENT PARTICLES. PART II. FIELD EVALUATION. (R826232)

    EPA Science Inventory

    Abstract

    This study presents results from a field evaluation of a mobile versatile aerosol concentration enrichment system (VACES), designed to enhance the ambient concentrations of ultrafine (less than 0.18 VERSATILE AEROSOL CONCENTRATION ENRICHMENT SYSTEM (VACES) FOR SIMULTANEOUS IN VIVO AND IN VITRO EVALUATION OF TOXIC EFFECTS OF ULTRAFINE, FINE AND COARSE AMBIENT PARTICLES. PART II: FIELD EVALUATION. (R827352C001)

    EPA Science Inventory

    This study presents results from a field evaluation of a mobile versatile aerosol concentration enrichment system (VACES), designed to enhance the ambient concentrations of ultrafine (less than 0.18 small m...</p>
      </li>

      <li>
      <p><a target=Background concentrations of individual and total volatile organic compounds in residential indoor air of Schleswig-Holstein, Germany.

    PubMed

    Hippelein, Martin

    2004-09-01

    During a monitoring campaign concentrations of volatile organic compounds (VOCs) were measured in indoor air of 79 dwellings where occupants had not complained about health problems or unpleasant odour. Parameters monitored were the individual concentration of 68 VOCs and the total concentration of all VOCs inside the room. VOCs adsorbed by Tenax TA were then analysed by means of thermal desorption, gas chromatography and mass spectrometry. The analytical procedure and quantification was done according to the recommendation of the ECA-IAQ Working Group 13 which gave a definition of the total volatile organic compound (TVOC) concentration. Using this recommendation TVOC-concentrations ranged between 33 and 1600 microg m(-3) with a median of 289 microg m(-3). Compounds found in every sample and with the highest concentrations were 2-propanol, alpha-pinene and toluene. Save for a few samples, all concentrations measured have been a factor 2 to 10 lower, compared to data from similar studies. Only a few terpenes and aldehydes were found exceeding published reference data or odour threshold concentrations. However, it has been found that sampling and analysing methods do have a considerable impact on the results, making direct comparisons of studies somewhat questionable. 47% of all samples revealed concentrations exceeding the threshold value of 300 microg TVOC m(-3) set by the German Federal Environmental Agency as a target for indoor air quality. Using the TVOC concentration as defined in the ECA-IAQ methodology is instrumental in assessing exposure to VOCs and identifying sources of VOCs. The background concentrations determined in this study can be used to discuss and interpret target values for individual and total volatile organic compounds in indoor air.

  2. Heavy-duty diesel engine NO{sub x} reduction with nitrogen-enriched combustion air. Final CRADA report.

    SciTech Connect

    McConnell, S.; Energy Systems

    2010-07-28

    The concept of engine emissions control by modifying intake combustion gas composition from that of ambient air using gas separation membranes has been developed during several programs undertaken at Argonne. These have led to the current program which is targeted at heavy-duty diesel truck engines. The specific objective is reduction of NO{sub x} emissions by the target engine to meet anticipated 2007 standards while extracting a maximum of 5 percent power loss and allowing implementation within commercial constraints of size, weight, and cost. This report includes a brief review of related past programs, describes work completed to date during the current program, and presents interim conclusions. Following a work schedule adjustment in August 2002 to accommodate problems in module procurement and data analysis, activities are now on schedule and planned work is expected to be completed in September, 2004. Currently, we believe that the stated program requirements for the target engine can be met, based upon extrapolation of the work completed. Planned project work is designed to experimentally confirm these projections and result in a specification for a module package that will meet program objectives.

  3. Seasonal variability of tritium and ion concentrations in rain at Kumamoto, Japan and back-trajectory analysis of air mass

    SciTech Connect

    Momoshima, N.; Sugihara, S.; Toyoshima, T.; Nagao, Y.; Takahashi, M.; Nakamura, Y.

    2008-07-15

    Tritium and major ion concentrations in rain were analyzed in Kumamoto (Japan)) between 2001 and 2006 to examine present tritium concentration and seasonal variation. The average tritium concentration was 0.36 {+-} 0.19 Bq/L (n=104) and higher tritium concentrations were observed in spring than the other seasons. Among the ions, non-sea-salt (nss) SO{sub 4}{sup 2}'- showed higher concentration in winter while other ions did not show marked increase in winter. Based on the back-trajectory analyses of air masses, the increase in tritium concentrations in spring arises from downward movement of naturally produced tritium from stratosphere to troposphere, while the increase of the nss-SO{sub 4}{sup 2-} concentrations in winter is due to long range transport of pollutants from China to Japan. (authors)

  4. Optimal Modeling of Urban Ambient Air Ozone Concentration Based on Its Precursors' Concentrations and Temperature, Employing Genetic Programming and Genetic Algorithm.

    PubMed

    Mousavi, Seyed Mahmoud; Husseinzadeh, Danial; Alikhani, Sadegh

    2014-04-01

    Efficient models are required to predict the optimum values of ozone concentration in different levels of its precursors' concentrations and temperatures. A novel model based on the application of a genetic programming (GP) optimization is presented in this article. Ozone precursors' concentrations and run time average temperature have been chosen as model's parameters. Generalization performances of two different homemade models based on genetic programming and genetic algorithm (GA), which can be used for calculating theoretical ozone concentration, are compared with conventional semi-empirical model performance. Experimental data of Mashhad city ambient air have been employed to investigate the prediction ability of properly trained GP, GA, and conventional semi-empirical models. It is clearly demonstrated that the in-house algorithm which is used for the model based on GP, provides better generalization performance over the model optimized with GA and the conventional semi-empirical ones. The proposed model is found accurate enough and can be used for urban air ozone concentration prediction.

  5. Uncertainty-weighted time averaging of mercury vapour concentrations in ambient air: application to measurements in the United kingdom.

    PubMed

    Brown, Richard J C; Muhunthan, Dharsheni

    2011-02-03

    Uncertainty-weighted time averaging of total gaseous mercury concentrations in ambient air, with associated robust uncertainties, has been performed for concentrations measured by the U.K. Heavy Metals Monitoring Network between 2007 and 2009. The results have been compared with averages produced using standard time-averaging methods with a view to investigating the properties of the new method and whether it represents an improvement over current practice.

  6. Blocking of the water-lunar fines reaction by air and water concentration effects

    NASA Technical Reports Server (NTRS)

    Gammage, R. B.; Holmes, H. F.

    1975-01-01

    The elements of air, if adsorbed in conjunction with water vapor or liquid water, are able to impede severely the attack of lunar fines. Thus is explained the stability of lunar fines in moisture laden air, and their small solubility in liquid, aerated water. In the absence of air, liquid water is more effective than water vapor in attacking the grains; the channels formed are wider and the expansion of area is greater.

  7. Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea.

    PubMed

    Baek, Sung-Ok; Suvarapu, Lakshmi Narayana; Seo, Young-Kyo

    2015-08-05

    This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs) including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory role in improving

  8. Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea

    PubMed Central

    Baek, Sung-Ok; Suvarapu, Lakshmi Narayana; Seo, Young-Kyo

    2015-01-01

    This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs) including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory role in improving

  9. Comparison of background levels of culturable fungal spore concentrations in indoor and outdoor air in southeastern Austria

    NASA Astrophysics Data System (ADS)

    Haas, D.; Habib, J.; Luxner, J.; Galler, H.; Zarfel, G.; Schlacher, R.; Friedl, H.; Reinthaler, F. F.

    2014-12-01

    Background concentrations of airborne fungi are indispensable criteria for an assessment of fungal concentrations indoors and in the ambient air. The goal of this study was to define the natural background values of culturable fungal spore concentrations as reference values for the assessment of moldy buildings. The concentrations of culturable fungi were determined outdoors as well as indoors in 185 dwellings without visible mold, obvious moisture problems or musty odor. Samples were collected using the MAS-100® microbiological air sampler. The study shows a characteristic seasonal influence on the background levels of Cladosporium, Penicillium and Aspergillus. Cladosporium sp. had a strong outdoor presence, whereas Aspergillus sp. and Penicillium sp. were typical indoor fungi. For the region of Styria, the median outdoor concentrations are between 100 and 940 cfu/m³ for culturable xerophilic fungi in the course of the year. Indoors, median background levels are between 180 and 420 cfu/m³ for xerophilic fungi. The I/O ratios of the airborne fungal spore concentrations were between 0.2 and 2.0. For the assessment of indoor and outdoor air samples the dominant genera Cladosporium, Penicillium and Aspergillus should receive special consideration.

  10. LOCATING NEARBY SOURCES OF AIR POLLUTION BY NONPARAMETRIC REGRESSION OF ATMOSPHERIC CONCENTRATIONS ON WIND DIRECTION. (R826238)

    EPA Science Inventory

    The relationship of the concentration of air pollutants to wind direction has been determined by nonparametric regression using a Gaussian kernel. The results are smooth curves with error bars that allow for the accurate determination of the wind direction where the concentrat...

  11. 10 CFR Appendix B to Part 20 - Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs) of Radionuclides for...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...,” and “Water,” are applicable to the assessment and control of dose to the public, particularly in the...). Consideration of non-stochastic limits has not been included in deriving the air and water effluent... water concentrations were derived by taking the most restrictive occupational stochastic oral...

  12. 10 CFR Appendix B to Part 20 - Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs) of Radionuclides for...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...,” and “Water,” are applicable to the assessment and control of dose to the public, particularly in the...). Consideration of non-stochastic limits has not been included in deriving the air and water effluent... water concentrations were derived by taking the most restrictive occupational stochastic oral...

  13. ORGANOCHLORINE PESTICIDE CONCENTRATIONS AND ENANTIOMER FRACTIONS FOR CHLORDANE IN INDOOR AIR FROM THE U.S. CORNBELT

    EPA Science Inventory

    Thirty-seven indoor air samples were collected and analyzed to determine if enantioselective degradation of past use organochlorine pesticides occurs indoors and to increase the available information on concentrations in homes. Samples were collected from homes in the U.S. cor...

  14. IN VITRO EFFECTS OF PARTICULATE MATTER ON AIRWAY EPITHELIAL CELLS ISOLATED FROM CONCENTRATED AIR PARTICLES-EXPOSED SPONTANEOUS HYPERTENSIVE RATS

    EPA Science Inventory

    In vitro effects of particulate matter on airway epithelial cells isolated from concentrated air particles-exposed spontaneous hypertensive rats

    Ines Pagan, Urmila Kodavanti, Paul Evansky, Daniel L Costa and Janice A Dye. U.S. Environmental Protection Agency, ORD, National...

  15. [Air negative charge ion concentration and its relationships with meteorological factors in different ecological functional zones of Hefei City].

    PubMed

    Wei, Chaoling; Wang, Jingtao; Jiang, Yuelin; Zhang, Qingguo

    2006-11-01

    Air negative charge ion concentration (ANCIC) has a close relationship with air quality. The observations on the ANCIC, sunlight intensity, air temperature, and air relative humidity in different ecological functional zones of Hefei City from 2003 to 2004 showed that the diurnal change pattern of ANCIC was of single peak in sightseeing and habitation zones, dual peak in industrial zone, and complicated in commercial zone. Different ecological functional zones had different appearance time of their daily ANCIC extremum. The diurnal fluctuation of ANCIC was in the order of commercial zone > industrial zone > habitation zone and sightseeing zone. The annual change pattern of ANCIC in these zones was similar, being the highest in summer and lowest in winter, and the mean annual ANCIC was 819, 340, 149 and 126 ions x cm(-3), respectively. The most important meteorological factor affecting the ANCIC in Hefei City was air relative humidity, followed by sunlight intensity and air temperature. There was an exponential relationship between ANCIC and air relative humidity.

  16. Effect of poverty on the relationship between personal exposures and ambient concentrations of air pollutants in Ho Chi Minh City

    NASA Astrophysics Data System (ADS)

    Mehta, Sumi; Sbihi, Hind; Dinh, Tuan Nguyen; Xuan, Dan Vu; Le Thi Thanh, Loan; Thanh, Canh Truong; Le Truong, Giang; Cohen, Aaron; Brauer, Michael

    2014-10-01

    Socioeconomic factors often affect the distribution of exposure to air pollution. The relationships between health, air pollution, and poverty potentially have important public health and policy implications, especially in areas of Asia where air pollution levels are high and income disparity is large. The objective of the study was to characterize the levels, determinants of exposure, and relationships between children personal exposures and ambient concentrations of multiple air pollutants amongst different socioeconomic segments of the population of Ho Chi Minh City, Vietnam. Using repeated (N = 9) measures personal exposure monitoring and determinants of exposure modeling, we compared daily average PM2.5, PM10, PM2.5 absorbance and NO2 concentrations measured at ambient monitoring sites to measures of personal exposures for (N = 64) caregivers of young children from high and low socioeconomic groups in two districts (urban and peri-urban), across two seasons. Personal exposures for both PM sizes were significantly higher among the poor compared to non-poor participants in each district. Absolute levels of personal exposures were under-represented by ambient monitors with median individual longitudinal correlations between personal exposures and ambient concentrations of 0.4 for NO2, 0.6 for PM2.5 and PM10 and 0.7 for absorbance. Exposures of the non-poor were more highly correlated with ambient concentrations for both PM size fractions and absorbance while those for NO2 were not significantly affected by socioeconomic position. Determinants of exposure modeling indicated the importance of ventilation quality, time spent in the kitchen, air conditioner use and season as important determinant of exposure that are not fully captured by the differences in socioeconomic position. Our results underscore the need to evaluate how socioeconomic position affects exposure to air pollution. Here, differential exposure to major sources of pollution, further influenced by

  17. The association of particulate air metal concentrations with heart rate variability.

    PubMed Central

    Magari, Shannon R; Schwartz, Joel; Williams, Paige L; Hauser, Russ; Smith, Thomas J; Christiani, David C

    2002-01-01

    Numerous studies show an association between particulate air pollution and adverse health effects. Particulate matter is a complex mixture of elemental carbon, ammonium, sulfates, nitrates, organic components, and metals. The mechanisms of action of particulate matter less than or equal to 2.5 micro m in mean aerodynamic diameter (PM(2.5)), as well as the constituents responsible for the observed cardiopulmonary health effects, have not been identified. In this study we focused on the association between the metallic component of PM(2.5) and cardiac autonomic function based on standard heart rate variability (HRV) measures in an epidemiologic study of boilermakers. Thirty-nine male boilermakers were monitored throughout a work shift. Each subject wore an ambulatory electrocardiogram (Holter) monitor and a personal monitor to measure PM(2.5). We used mixed-effects models to regress heart rate and SDNN index (standard deviation of the normal-to-normal) on PM(2.5) and six metals (vanadium, nickel, chromium, lead, copper, and manganese). There were statistically significant mean increases in the SDNN index of 11.30 msec and 3.98 msec for every 1 micro g/m(3) increase in the lead and vanadium concentrations, respectively, after adjusting for mean heart rate, age, and smoking status. Small changes in mean heart rate were seen with all exposure metrics. The results of this study suggest an association between exposure to airborne metals and significant alterations in cardiac autonomic function. These results extend our understanding of the adverse health effects of the metals component of ambient PM(2.5). PMID:12204821

  18. Air concentrations and wet deposition of major inorganic ions at five non-urban sites in China, 2001-2003

    NASA Astrophysics Data System (ADS)

    Aas, Wenche; Shao, Min; Jin, Lei; Larssen, Thorjørn; Zhao, Dawei; Xiang, Renjun; Zhang, Jinhong; Xiao, Jinsong; Duan, Lei

    Air and precipitation measurements at five sites were undertaken from 2001 to 2003 in four different provinces in China, as part of the acid rain monitoring program IMPACTS. The sites were located in Tie Shan Ping (TSP) in Chongqing, Cai Jia Tang (CJT) in Hunan, Lei Gong Shan (LGS) and Liu Chong Guan (LCG) in Guizhou and Li Xi He (LXH) in Guangdong. The site characteristics are quite varied with TSP and LCG located relatively near big cites while the three others are situated in more regionally representative areas. The distances to urban centres are reflected in the air pollution concentrations, with annual average concentrations of SO 2 ranging from 0.5 to above 40 μg S m -3. The main components in the airborne particles are (NH 4) 2SO 4 and CaSO 4. Reduced nitrogen has a considerably higher concentration level than oxidised nitrogen, reflecting the high ammonia emissions from agriculture. The gas/particle ratio for the nitrogen compounds is about 1:1 at all the three intensive measurement sites, while for sulphur it varies from 2.5 to 0.5 depending on the distance to the emission sources. As in air, the predominant ions in precipitation are sulphate, calcium and ammonium. The volume weighted annual concentration of sulphate ranges from about 70 μeq l -1 at the most rural site (LGS) to about 200 μeq l -1 at TSP and LCG. The calcium concentration ranges from 25 to 250 μeq l -1, while the total nitrogen concentration is between 30 and 150 μeq l -1; ammonium is generally twice as high as nitrate. China's acid rain research has traditionally been focused on urban sites, but these measurements show a significant influence of long range transported air pollutants to rural areas in China. The concentration levels are significantly higher than seen in most other parts of the world.

  1. Prevalence and Serogroup Diversity of Salmonella for Broiler Neck Skin, Whole Carcass Rinse, and Whole Carcass Enrichment Sampling Methodologies following Air or Immersion Chilling.

    PubMed

    Bourassa, D V; Holmes, J M; Cason, J A; Cox, N A; Rigsby, L L; Buhr, R J

    2015-11-01

    The purpose of this study was to evaluate neck skin (NS), whole carcass rinse (WCR), and whole carcass enrichment (WCE) sampling procedures for Salmonella isolation and serogroup identification from the same broiler chicken carcass treated with air or immersion chilling. Commercially processed and eviscerated broiler carcasses were collected from a commercial processing plant, individually bagged, and transported to the pilot processing plant. In experiment 1, carcasses were air chilled to 4°C. In experiment 2, carcasses were immersion chilled with or without chlorine. After air chilling, Salmonella was detected on 78% of NS and 89% of WCE samples. Only one Salmonella serogroup was detected from each of 13 Salmonella-positive NS samples, and two serogroups were detected on 1 Salmonella-positive NS sample. Only one Salmonella serogroup was detected from each of 13 Salmonella-positive WCE samples, and two serogroups were detected from 3 Salmonella-positive WCE samples. After immersion chilling without chlorine, Salmonella was detected on 38% of NS, 45% of WCR, and 100% of WCE samples. Without chlorine, the 15 Salmonella-positive NS samples included 14 samples with one serogroup and 1 sample with two serogroups. Only one Salmonella serogroup was detected from WCR samples after immersion chilling. Of 40 Salmonella-positive WCE samples, 23 had a one, 14 had two, and 3 had three Salmonella serogroups. After immersion chilling with chlorine, Salmonella was detected on 35% of NS, 0% of WCR, and 90% of WCE samples. With chlorine, the 14 Salmonella-positive NS samples included 11 samples with one serogroup and 3 samples with two serogroups. No Salmonella serogroups were detected from WCR samples after immersion chilling with 20 mg/liter free chlorine. The 36 Salmonella-positive WCE samples included 21 samples with one serogroup and 15 samples with two serogroups. NS and WCE sampling methodologies yielded similar prevalence and serogroup diversity after air chilling. However

  2. Diagnostic Analysis of Ozone Concentrations Simulated by Two Regional-Scale Air Quality Models

    EPA Science Inventory

    Since the Community Multiscale Air Quality modeling system (CMAQ) and the Weather Research and Forecasting with Chemistry model (WRF/Chem) use different approaches to simulate the interaction of meteorology and chemistry, this study compares the CMAQ and WRF/Chem air quality simu...

  3. Analysis of mobile source air toxics (MSATs)–Near-Road VOC and carbonyl concentrations

    EPA Science Inventory

    Exposures to mobile source air toxics (MSATs) have been associated with numerous adverse health effects. While thousands of air toxic compounds are emitted from mobile sources, a subset of compounds are considered high priority due to their significant contribution to cancer and...

  4. Evaluation of background soil and air polychlorinated biphenyl (PCB) concentrations on a hill at the outskirts of a metropolitan city.

    PubMed

    Kuzu, S Levent; Saral, Arslan; Güneş, Gülten; Karadeniz, Aykut

    2016-07-01

    Air and soil sampling was conducted inside a forested area for 22 months. The sampling location is situated to the north of a metropolitan city. Average atmospheric gas and particle concentrations were found to be 180 and 28 pg m(-3) respectively, while that of soil phase was detected to be 3.2 ng g(-1) on dry matter, The congener pairs of PCB#4-10 had the highest contribution to each medium. TEQ concentration was 0.10 pg m(-3), 0.07 pg m(-3), 21.92 pg g(-1), for gas, particle and soil phases, respectively. PCB#126 and PCB#169 contributed to over 99% of the entire TEQ concentrations for each medium. Local sources were investigated by conditional probability function (CPF) and soil/air fugacity. Landfilling area and medical waste incinerator, located to the 8 km northeast, contributed to ambient concentrations, especially in terms of dioxin-like congeners. The industrial settlement (called Dilovasi being to the east southeast of 60 km distant) contributed from southeast direction. Further sources were identified by potential source contribution function (PSCF). Sources at close proximity had high contribution. Air mass transportation from Aliaga industrial region (being to the southwest of 300 km distant) moderately contributed to ambient concentrations. Low molecular weight congeners were released from soil body. 5-CBs and 6-CBs were close to equilibrium state between soil/air interfaces. PCB#171 was close to equilibrium and PCB#180 was likely to evaporate from soil, which constitute 7-CBs. PCB#199, representing 8-CBs deposited to soil. 9-CB (PCB#207) was in equilibrium between soil and air phases. PMID:27038903

  5. Leaf conductance decreased under free-air CO2 enrichment (FACE) for three perennials in the Nevada desert

    USGS Publications Warehouse

    Nowak, Robert S.; Defalco, Lesley A.; Wilcox, Carolyn S.; Jordan, Dean N.; Coleman, James S.; Seemann, Jeffrey R.; Smith, Stanley D.

    2001-01-01

    A common response of plants to elevated atmospheric CO2 concentration (CO2) is decreased leaf conductance. Consequently, leaf temperature is predicted to increase under elevated CO2.Diurnal patterns of leaf conductance and temperature were measured for three desert perennials, the C3 shrub Larrea tridentata, C3 tussock grass Achnatherum hymenoides and C4tussock grass Pleuraphis rigida, at the Nevada Desert FACE facility. Measurements were made on ambient and c. 550 µmol mol−1 CO2 plots through both a wet and dry year.Reductions in conductance were 35%, 20% and 13% for Pleuraphis, Achnatherum and Larrea, respectively. Decreased conductance occurred throughout the day only for Pleuraphis. Both C3species had smaller CO2 effects during dry periods than wet. Leaf temperature did not differ significantly between elevated and ambient CO2 for any species. Comparisons of blower-control and nonring plots indicated that the FACE apparatus did not confound our results.All three species exhibited decreased leaf conductance under elevated CO2, although reductions were not uniform during the day or among years. Nonetheless, leaf energy balance was only minimally changed for these microphyllous desert perennials.

  6. [Relationship of the ambient air concentrations of chemical substances to the spread of allergic diseases in children].

    PubMed

    Galeev, K A; Khakimova, R F

    2002-01-01

    The role of some ingredients that contaminate the ambient air in the occurrence and development of allergic diseases was studied. The closest relationships were found between the concentrations of hydrogen sulfide and the prevalence of eczema (rxy +/- m = 0.48 +/- 0.15). There was a direct correlation between the concentrations of each ingredient and the incidence of neurodermitis among children. The correlation between the summarized concentrations of ingredients and the incidence of bronchial asthma among children was rxy +/- m = 0.71 +/- 0.19. The findings serves as the basis for elaborating measures to reduce ecological tension and the incidence of allergic diseases in children. PMID:12380496

  7. Variability of concentrations of polybrominated diphenyl ethers and polychlorinated biphenyls in air: implications for monitoring, modeling and control

    NASA Astrophysics Data System (ADS)

    Gouin, T.; Harner, T.; Daly, G. L.; Wania, F.; Mackay, D.; Jones, K. C.

    Monitoring data indicate that organic compounds with high octanol-air partition coefficients ( KOA), such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) exhibit seasonally variable air concentrations, especially during early spring, shortly after snow melt and before bud-burst when levels are elevated. This variability can complicate the interpretation of monitoring data designed to assess year-to-year changes. It is suggested that relatively simple dynamic multimedia mass balance models can assist interpretation by "factoring out" variability attributable to temperature and other seasonal effects as well as identifying likely contaminant sources. To illustrate this approach, high-volume air samples were collected from January to June, 2002 at a rural location in southern Ontario. Gas-phase concentrations for both ΣPBDE and ΣPCB rose from below the detection limit during the winter to 19 and 110 pg m -3, respectively, in early spring, only to decrease again following bud-burst. Passive air samples (PAS), deployed at seven urban, rural and remote sites for two one-month periods prior and following bud-burst, indicate a strong urban-rural gradient for both the PBDEs and PCBs. Calculated air concentrations from the PAS are shown to agree favorably with the high-volume air sampling data, with concentrations ranging 6-85 pg m -3 and 6-360 pg m -3 for ΣPBDE and ΣPCB, respectively. Concentrations in urban areas are typically 5 times greater than in rural locations. These data were interpreted using simulation results from a fate model including a seasonally variable forest canopy and snow pack, suggesting that the primary source is urban and that the "spring pulse" is the result of several interacting factors. Such contaminants are believed to be efficiently deposited in winter, accumulate in the snow pack and are released to terrestrial surfaces upon snow melt in spring. Warmer temperatures cause volatilization and a rise in air

  8. An oxygen enrichment device for lowlanders ascending to high altitude

    PubMed Central

    2013-01-01

    Background When ascending to the high altitude, people living in low altitude areas will suffer from acute mountain sickness. The aim of this study is to test the hypothesis that whether an oxygen concentration membrane can be made and used to construct a new portable oxygen enrichment device for individuals in acute exposure to the high altitude. Methods The membrane was fabricated using vinylsiloxane rubber, polyphenylene oxide hydrogen silicone polymers, chloroplatinic acid and isopropyl alcohol. The membrane was assembled in a frame and the performance was tested in terms of concentration of oxygen, flow rate of oxygen enriched air, pressure ratio across the membrane and ambient temperature. Furthermore, the oxygen concentration device was constructed using the membrane, a DC fan, vacuum pump and gas buffer. A nonrandomized preliminary field test was conducted, in which eight healthy male subjects were flown to Tibet (Lhasa, 3,700 m). First, subjects wore the oxygen enrichment device and performed an incremental exercise on cycle ergometer. The test included heart rate (HR), saturation of peripheral oxygen (SpO2) and physical work capacity (PWC). Then, after a rest period of 4 hours, the experimental protocol was repeated without oxygen enrichment device. Results The testing showed that the membrane could increase the oxygen concentration by up to 30%. Simulation test indicated that although the performance of the oxygen enrichment device decreased with altitudes, the oxygen concentration could still maintain 28% with flow rate of enriched air 110 cm3/s at 5000 m. The field test showed that higher SpO2, lower HR, and better PWC (measured by the PWC-170) were observed from all the subjects using oxygen enrichment device compared with non-using (P < 0.01). Conclusions We concluded that the new portable oxygen enrichment device would be effective in improving exercise performance when ascending to the high altitude. PMID:24103365

  9. Assessment of an aerosol treatment to improve air quality in a swine concentrated animal feeding operation (CAFO).

    PubMed

    Rule, Ana M; Chapin, Amy R; McCarthy, Sheila A; Gibson, Kristen E; Schwab, Kellogg J; Buckley, Timothy J

    2005-12-15

    Poor air quality within swine concentrated animal feeding operations (CAFOs) poses a threat to workers, the surrounding community, and farm production. Accordingly, the current study was conducted to evaluate a technology for reducing air pollution including particulate matter (PM), viable bacteria, and ammonia within such a facility. The technology consists of an acid-oil-alcohol aerosol applied daily. Its effectiveness was evaluated by comparing air quality from before to after treatment and between treated and untreated sides of a barn separated by an impervious partition. On the untreated side, air quality was typical for a swine CAFO, with mean PM2.5 of 0.28 mg/m3 and PM(TOT) of 1.5 mg/m3. The treatment yielded a reduction in PM concentration of 75-90% from before to after treatment. Effectiveness increased with time, application, and particle size (40% reduction for 1 microm and 90% for >10 microm). Airborne bacteria levels (total bacteria, Enterobacteriaceae, and gram-positive cocci) decreased one logarithmic unit after treatment. In contrast, treatment had no effect on ammonia concentrations. These findings demonstrate the effectiveness of an intervention in yielding exposure and emission reductions. PMID:16475347

  10. Evaluation of 11 terrestrial carbon-nitrogen cycle models against observations from two temperate Free-Air CO2 Enrichment studies.

    PubMed

    Zaehle, Sönke; Medlyn, Belinda E; De Kauwe, Martin G; Walker, Anthony P; Dietze, Michael C; Hickler, Thomas; Luo, Yiqi; Wang, Ying-Ping; El-Masri, Bassil; Thornton, Peter; Jain, Atul; Wang, Shusen; Warlind, David; Weng, Ensheng; Parton, William; Iversen, Colleen M; Gallet-Budynek, Anne; McCarthy, Heather; Finzi, Adrien; Hanson, Paul J; Prentice, I Colin; Oren, Ram; Norby, Richard J

    2014-05-01

    We analysed the responses of 11 ecosystem models to elevated atmospheric [CO2 ] (eCO2 ) at two temperate forest ecosystems (Duke and Oak Ridge National Laboratory (ORNL) Free-Air CO2 Enrichment (FACE) experiments) to test alternative representations of carbon (C)-nitrogen (N) cycle processes. We decomposed the model responses into component processes affecting the response to eCO2 and confronted these with observations from the FACE experiments. Most of the models reproduced the observed initial enhancement of net primary production (NPP) at both sites, but none was able to simulate both the sustained 10-yr enhancement at Duke and the declining response at ORNL: models generally showed signs of progressive N limitation as a result of lower than observed plant N uptake. Nonetheless, many models showed qualitative agreement with observed component processes. The results suggest that improved representation of above-ground-below-ground interactions and better constraints on plant stoichiometry are important for a predictive understanding of eCO2 effects. Improved accuracy of soil organic matter inventories is pivotal to reduce uncertainty in the observed C-N budgets. The two FACE experiments are insufficient to fully constrain terrestrial responses to eCO2 , given the complexity of factors leading to the observed diverging trends, and the consequential inability of the models to explain these trends. Nevertheless, the ecosystem models were able to capture important features of the experiments, lending some support to their projections.

  11. Evaluation of 11 terrestrial carbon–nitrogen cycle models against observations from two temperate Free-Air CO2 Enrichment studies

    PubMed Central

    Zaehle, Sönke; Medlyn, Belinda E; De Kauwe, Martin G; Walker, Anthony P; Dietze, Michael C; Hickler, Thomas; Luo, Yiqi; Wang, Ying-Ping; El-Masri, Bassil; Thornton, Peter; Jain, Atul; Wang, Shusen; Warlind, David; Weng, Ensheng; Parton, William; Iversen, Colleen M; Gallet-Budynek, Anne; McCarthy, Heather; Finzi, Adrien; Hanson, Paul J; Prentice, I Colin; Oren, Ram; Norby, Richard J

    2014-01-01

    We analysed the responses of 11 ecosystem models to elevated atmospheric [CO2] (eCO2) at two temperate forest ecosystems (Duke and Oak Ridge National Laboratory (ORNL) Free-Air CO2 Enrichment (FACE) experiments) to test alternative representations of carbon (C)–nitrogen (N) cycle processes. We decomposed the model responses into component processes affecting the response to eCO2 and confronted these with observations from the FACE experiments. Most of the models reproduced the observed initial enhancement of net primary production (NPP) at both sites, but none was able to simulate both the sustained 10-yr enhancement at Duke and the declining response at ORNL: models generally showed signs of progressive N limitation as a result of lower than observed plant N uptake. Nonetheless, many models showed qualitative agreement with observed component processes. The results suggest that improved representation of above-ground–below-ground interactions and better constraints on plant stoichiometry are important for a predictive understanding of eCO2 effects. Improved accuracy of soil organic matter inventories is pivotal to reduce uncertainty in the observed C–N budgets. The two FACE experiments are insufficient to fully constrain terrestrial responses to eCO2, given the complexity of factors leading to the observed diverging trends, and the consequential inability of the models to explain these trends. Nevertheless, the ecosystem models were able to capture important features of the experiments, lending some support to their projections. PMID:24467623

  12. Interoceptive fear conditioning as a learning model of panic disorder: an experimental evaluation using 20% CO(2)-enriched air in a non-clinical sample.

    PubMed

    Acheson, Dean T; Forsyth, John P; Prenoveau, Jason M; Bouton, Mark E

    2007-10-01

    Despite the role afforded interoceptive fear conditioning in etiologic accounts of panic disorder, there are no good experimental demonstrations of such learning in humans. The aim of the present study was to evaluate the interoceptive conditioning account using 20% carbon dioxide (CO(2))-enriched air as an interoceptive conditioned stimulus (CS) (i.e., physiologically inert 5-s exposures) and unconditioned stimulus (US) (i.e., physiologically prepotent 15-s exposures). Healthy participants (N=42) were randomly assigned to one of three conditions: a CS-only, contingent CS-US pairings, or unpaired/non-contingent CS and US presentations. Electrodermal and self-report (e.g., distress, fear) served as indices of conditioned emotional responding. Results showed greater magnitude electrodermal and evaluative fear conditioning in the paired relative to the CS-only condition. The explicitly unpaired condition showed even greater electrodermal and evaluative responding during acquisition, and marked resistance to extinction. The latter results are consistent with the possibility that the unpaired procedure constituted a partial reinforcement procedure in which CO(2) onset was paired with more extended CO(2) exposure on 50% of the trials. Overall, the findings are consistent with contemporary learning theory accounts of panic.

  13. Relationships between ozone photolysis rates and peroxy radical concentrations in clean marine air over the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Penkett, S. A.; Monks, P. S.; Carpenter, L. J.; Clemitshaw, K. C.; Ayers, G. P.; Gillett, R. W.; Galbally, I. E.; Meyer, C. P.

    1997-06-01

    Measurements of the sum of inorganic and organic peroxy radicals (RO2) and photolysis rate coefficients J(NO2) and J(O1D) have been made at Cape Grim, Tasmania in the course of a comprehensive experiment which studied photochemistry in the unpolluted marine boundary layer. The SOAPEX (Southern Ocean Atmospheric Photochemistry Experiment) campaign included measurements of ozone, peroxides, nitrogen oxides, water vapor, and many other parameters. This first full length paper concerned with the experiment focuses on the types of relationships observed between peroxy radicals and J(NO2), J(O1D) and √[J(O1D)] in different air masses in which ozone is either produced or destroyed by photochemistry. It was found that in baseline air with ozone loss, RO2 was proportional to √[J(O1D)], whereas in more polluted air RO2 was proportional to J(O1D). Simple algorithms were derived to explain these relationships and also to calculate the concentrations of OH radicals in baseline air from the instantaneous RO2 concentrations. The signal to noise ratio of the peroxy radical measurements was up to 10 for 1-min values and much higher than in other previous deployments of the instrument in the northern hemisphere, leading to the confident determination of the relationships between RO2 and J(O1D) in different conditions. The absolute concentration Of RO2 determined in these experiments is in some doubt, but this does not affect our conclusions concerned either with the behavior of peroxy radicals with changing light levels or with the concentrations of OH calculated from RO2. The results provide confidence that the level of understanding of the photochemistry of ozone leading to the production of peroxide via recombination of peroxy radicals in clean air environments is well advanced.

  14. REVIEW OF CONCENTRATION STANDARDS AND GUIDELINES FOR FUNGI IN INDOOR AIR

    EPA Science Inventory

    The paper reviews and compares existing guidelines for indoor airborne fungi, discusses limitations of existing guidelines, and identifies research needs that should contribute to the development of realistic and useful guidelines for these important air pollutants. (NOTE: Exposu...

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

    EPA Science Inventory

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

  16. Short-term effects of air temperature on plasma metabolite concentrations in patients undergoing cardiac cattheterization.

    EPA Science Inventory

    BACKGROUND: Epidemiological studies have shown associations between air temperature and cardiovascular health outcomes. Metabolic dysregulation might also play a role in the development of cardiovascular disease.OBJECTIVES: To investigate short-term temperature effects on metabol...

  17. ASSESSING THE COMPARABILITY OF AMMONIUM, NITRATE AND SULFATE CONCENTRATIONS MEASURED BY THREE AIR QUALITY MONITORING NETWORKS

    EPA Science Inventory

    Airborne fine particulate matter across the United States is monitored by different networks, the three prevalent ones presently being the Clean Air Status and Trend Network (CASTNet), the Interagency Monitoring of PROtected Visual Environment Network (IMPROVE) and the Speciati...

  18. Air pollution and associated human mortality: The role of air pollutant emissions, climate change and methane concentration increases during the industrial period

    NASA Astrophysics Data System (ADS)

    Fang, Y.; Naik, V.; Horowitz, L. W.; Mauzerall, D. L.

    2012-12-01

    Increases in surface ozone (O3) and fine particulate matter (≤ 2.5μm aerodynamic diameter, PM2.5) are associated with excess premature human mortalities. Here we estimate changes in surface O3 and PM2.5 since preindustrial (1860) times and the global present-day (2000) premature human mortalities associated with these changes. We go beyond previous work to analyze and differentiate the contribution of three factors: changes in emissions of short-lived air pollutants, climate change, and increased methane (CH4) concentrations, to air pollution levels and the associated premature mortalities. We use a coupled chemistry-climate model in conjunction with global population distributions in 2000 to estimate exposure attributable to concentration changes since 1860 from each factor. Attributable mortalities are estimated using health impact functions of long-term relative risk estimates for O3 and PM2.5 from the epidemiology literature. We find global mean surface PM2.5 and health-relevant O3 (defined as the maximum 6-month mean of 1-hour daily maximum O3 in a year) have increased by 8±0.16 μg/m3 and 30±0.16 ppbv, respectively, over this industrial period as a result of combined changes in emissions of air pollutants (EMIS), climate (CLIM) and CH4 concentrations (TCH4). EMIS, CLIM and TCH4 cause global average PM2.5 (O3) to change by +7.5±0.19 μg/m3 (+25±0.30 ppbv), +0.4±0.17 μg/m3 (+0.5±0.28 ppbv), and -0.02±0.01 μg/m3 (+4.3±0.33 ppbv), respectively. Total changes in PM2.5 are associated with 1.5 (95% confidence interval, CI, 1.0-2.5) million all-cause mortalities annually and in O3 are associated with 375 (95% CI, 129-592) thousand respiratory mortalities annually. Most air pollution mortality is driven by changes in emissions of short-lived air pollutants and their precursors (95% and 85% of mortalities from PM2.5 and O3 respectively). However, changing climate and increasing CH4 concentrations also increased premature mortality associated with air

  19. Air pollution and associated human mortality: the role of air pollutant emissions, climate change and methane concentration increases during the industrial period

    NASA Astrophysics Data System (ADS)

    Fang, Y.; Naik, V.; Horowitz, L. W.; Mauzerall, D. L.

    2012-09-01

    Increases in surface ozone (O3) and fine particulate matter (≤2.5 μm} aerodynamic diameter, PM2.5) are associated with excess premature human mortalities. Here we estimate changes in surface O3 and PM2.5 since preindustrial (1860) times and the global present-day (2000) premature human mortalities associated with these changes. We go beyond previous work to analyze and differentiate the contribution of three factors: changes in emissions of short-lived air pollutants, climate change, and increased methane (CH4) concentrations, to air pollution levels and the associated premature mortalities. We use a coupled chemistry-climate model in conjunction with global population distributions in 2000 to estimate exposure attributable to concentration changes since 1860 from each factor. Attributable mortalities are estimated using health impact functions of long-term relative risk estimates for O3 and PM2.5 from the epidemiology literature. We find global mean surface PM2.5 and health-relevant O3 (defined as the maximum 6-month mean of 1-h daily maximum O3 in a year) have increased by 8 ± 0.16 μg m-3 and 30 ± 0.16 ppbv, respectively, over this industrial period as a result of combined changes in emissions of air pollutants (EMIS), climate (CLIM) and CH4 concentrations (TCH4). EMIS, CLIM and TCH4 cause global average PM2.5(O3) to change by +7.5 ± 0.19 μg m-3 (+25 ± 0.30 ppbv), +0.4 ± 0.17 μg m-3 (+0.5 ± 0.28 ppbv), and -0.02 ± 0.01 μg m-3 (+4.3 ± 0.33 ppbv), respectively. Total changes in PM2.5 are associated with 1.5 (95% confidence interval, CI, 1.0-2.5) million all-cause mortalities annually and in O3 are associated with 375 (95% CI, 129-592) thousand respiratory mortalities annually. Most air pollution mortality is driven by changes in emissions of short-lived air pollutants and their precursors (95% and 85% of mortalities from PM2.5 and O3, respectively). However, changing climate and increasing CH4 concentrations also increased premature mortality

  20. Radon ((222)Rn) concentration in indoor air near the coal mining area of Nui Beo, North of Vietnam.

    PubMed

    Nhan, Dang Duc; Fernando, Carvalho P; Thu Ha, Nguyen Thi; Long, Nguyen Quang; Thuan, Dao Dinh; Fonseca, Heloisa

    2012-08-01

    Concentrations of radioactive radon gas ((222)Rn) were measured using passive monitors based on LR115 solid state track detectors during June-July 2010 in indoor air of dwellings in the Nui Beo coal mining area, mostly in Cam Pha and Ha Long coastal towns, Quang Ninh province, in the North of Vietnam. Global results of (222)Rn concentrations indoors varied from ≤6 to 145 Bq m(-3) averaging 46 ± 26 Bq m(-3) (n = 37), with a median value of 47 Bq m(-3). This was similar to outdoor (222)Rn concentrations in the region, averaging 43 ± 19 Bq m(-3) (n = 10), with a median value of 44 Bq m(-3). Indoor (222)Rn concentrations in the coastal town dwellings only were in average lower although not significantly different from indoor (222)Rn concentrations measured at the coal storage field near the harbor, 67 ± 4 Bq m(-3) (n = 3). Furthermore, there was no significant difference in the average (222)Rn concentration in indoor air measured in the coastal towns region and those at the touristic Tuan Chau Island located about 45 km south of the coal mine, in the Ha Long Bay. The indoor (222)Rn concentration in a floating house at the Bai Tu Long Bay, and assumed as the best estimate of the baseline (222)Rn in surface air, was 27 ± 3 Bq m(-3) (n = 3). Indoor average concentration of (222)Rn in dwellings at the Ha Noi city, inland and outside the coal mining area, was determined at 30 Bq m(-3). These results suggest that (222)Rn exhalation from the ground at the Nui Beo coal mining area may have contributed to generally increase (222)Rn concentration in the surface air of that region up to 1.7 times above the baseline value measured at the Bai Tu Long Bay and Ha Noi. The average indoor concentration of (222)Rn in Cam Pha-Ha Long area is about one-third of the value of the so-called Action Level set up by the US EPA of 148 Bq m(-3). Results suggest that there is no significant public health risk from (222)Rn exposure in the study region.

  1. Effects of diesel exhaust aftertreatment devices on concentrations and size distribution of aerosols in underground mine air.

    PubMed

    Bugarski, Aleksandar D; Schnakenberg, George H; Hummer, Ion A; Cauda, Emanuele; Janisko, Samuel I; Patts, Larry D

    2009-09-01

    Three types of uncatalyzed diesel particulate filter (DPF) systems, three types of high-temperature disposable filter elements (DFEs), and one diesel oxidation catalytic converter (DOC) were evaluated in underground mine conditions for their effects on the concentrations and size distributions of diesel aerosols. Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. The DPF systems reduced total mass of aerosols in the mine air approximately 10-fold for light-load and 20-fold or more for high-load test conditions. The DFEs offered similar reductions in aerosol mass concentrations. The efficiency of the new DFEs significantly increased with accumulation of operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on performance of the filter element The effectiveness of DPFs and DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for both DPFs and DFEs when the engine was operated at high-load modes than at low-load modes. The effects of the DOC on mass and number concentrations of aerosols in mine air were relatively minor when compared to those of the DPF and DFE systems.

  2. Temperature Programmed Desorption of Quench-condensed Krypton and Acetone in Air; Selective Concentration of Ultra-trace Gas Components.

    PubMed

    Suzuki, Taku T; Sakaguchi, Isao

    2016-01-01

    Selective concentration of ultra-trace components in air-like gases has an important application in analyzing volatile organic compounds in the gas. In the present study, we examined quench-condensation of the sample gas on a ZnO substrate below 50 K followed by temperature programmed desorption (TPD) (low temperature TPD) as a selective gas concentration technique. We studied two specific gases in the normal air; krypton as an inert gas and acetone as a reactive gas. We evaluated the relationship between the operating condition of low temperature TPD and the lowest detection limit. In the case of krypton, we observed the selective concentration by exposing at 6 K followed by thermal desorption at about 60 K. On the other hand, no selectivity appeared for acetone although trace acetone was successfully concentrated. This is likely due to the solvent effect by a major component in the air, which is suggested to be water. We suggest that pre-condensation to remove the water component may improve the selectivity in the trace acetone analysis by low temperature TPD.

  3. Temperature Programmed Desorption of Quench-condensed Krypton and Acetone in Air; Selective Concentration of Ultra-trace Gas Components.

    PubMed

    Suzuki, Taku T; Sakaguchi, Isao

    2016-01-01

    Selective concentration of ultra-trace components in air-like gases has an important application in analyzing volatile organic compounds in the gas. In the present study, we examined quench-condensation of the sample gas on a ZnO substrate below 50 K followed by temperature programmed desorption (TPD) (low temperature TPD) as a selective gas concentration technique. We studied two specific gases in the normal air; krypton as an inert gas and acetone as a reactive gas. We evaluated the relationship between the operating condition of low temperature TPD and the lowest detection limit. In the case of krypton, we observed the selective concentration by exposing at 6 K followed by thermal desorption at about 60 K. On the other hand, no selectivity appeared for acetone although trace acetone was successfully concentrated. This is likely due to the solvent effect by a major component in the air, which is suggested to be water. We suggest that pre-condensation to remove the water component may improve the selectivity in the trace acetone analysis by low temperature TPD. PMID:27063719

  4. Evaluation of Land Use Regression Models Used to Predict Air Quality Concentrations in an Urban Area

    EPA Science Inventory

    Cohort studies designed to estimate human health effects of exposures to urban pollutants require accurate determination of ambient concentrations in order to minimize exposure misclassification errors. However, it is often difficult to collect concentration information at each s...

  5. A Method for Estimating Urban Background Concentrations in Support of Hybrid Air Pollution Modeling for Environmental Health Studies

    PubMed Central

    Arunachalam, Saravanan; Valencia, Alejandro; Akita, Yasuyuki; Serre, Marc L.; Omary, Mohammad; Garcia, Valerie; Isakov, Vlad

    2014-01-01

    Exposure studies rely on detailed characterization of air quality, either from sparsely located routine ambient monitors or from central monitoring sites that may lack spatial representativeness. Alternatively, some studies use models of various complexities to characterize local-scale air quality, but often with poor representation of background concentrations. A hybrid approach that addresses this drawback combines a regional-scale model to provide background concentrations and a local-scale model to assess impacts of local sources. However, this approach may double-count sources in the study regions. To address these limitations, we carefully define the background concentration as the concentration that would be measured if local sources were not present, and to estimate these background concentrations we developed a novel technique that combines space-time ordinary kriging (STOK) of observations with outputs from a detailed chemistry-transport model with local sources zeroed out. We applied this technique to support an exposure study in Detroit, Michigan, for several pollutants (including NOx and PM2.5), and evaluated the estimated hybrid concentrations (calculated by combining the background estimates that addresses this issue of double counting with local-scale dispersion model estimates) using observations. Our results demonstrate the strength of this approach specifically by eliminating the problem of double-counting reported in previous hybrid modeling approaches leading to improved estimates of background concentrations, and further highlight the relative importance of NOx vs. PM2.5 in their relative contributions to total concentrations. While a key limitation of this approach is the requirement for another detailed model simulation to avoid double-counting, STOK improves the overall characterization of background concentrations at very fine spatial scales. PMID:25321872

  6. AIRNET Data from Los Alamos National Laboratory: Air Concentration Data by Site and Isotope/Element

    DOE Data Explorer

    Ambient monitoring is the systematic, long-term assessment of pollutant levels by measuring the quantity and types of certain pollutants in the surrounding, outdoor air. The purpose of AIRNET, LANL's ambient air monitoring network, is to monitor locations where people live or work. The community of Los Alamos is downwind from LANL, so there are many monitoring stations in and around the town. AIRNET stations monitor 24 hours a day, 365 days of the year. Particulates are collected on a filter and analyzed every two weeks for identification of analytes and assessment of the potential impact on the public. Emissions measurement is the process of monitoring materials vented from buildings. Air samples are taken from building exhaust units, called stacks, and are then analyzed for particulate matter, tritium, and radioactive gases and vapors. A computer model uses the emission data to determine the dispersion. Stack monitoring is also used to measure emissions that cannot be measured by AIRNET stations.

  7. Comparison of two different passive air samplers (PUF-PAS versus SIP-PAS) to determine time-integrated average air concentration of volatile hydrophobic organic pollutants

    NASA Astrophysics Data System (ADS)

    Kim, Seung-Kyu; Park, Jong-Eun

    2014-06-01

    Despite remarkable achievements with r some chemicals, a field-measurement technique has not been advanced for volatile hydrophobic organic chemicals (HOCs) that are the subjects of international concern. This study assesses the applicability of passive air sampling (PAS) by comparing PUF-PAS and its modified SIP-PAS which was made by impregnating XAD-4 powder into PUF, overviewing the principles of PAS, screening sensitive parameters, and determining the uncertainty range of PAS-derived concentration. The PAS air sampling rate determined in this study, corrected by a co-deployed low-volume active air sampler (LAS) for neutral PFCs as model chemicals, was ˜1.2 m3 day-1. Our assessment shows that the improved sorption capacity in a SIP lengthens PAS deployment duration by expanding the linear uptake range and then enlarges the effective air sampling volume and detection frequency of chemicals at trace level. Consequently, volatile chemicals can be collected during sufficiently long times without reaching equilibrium when using SIP, while this is not possible for PUF. The most sensitive parameter to influence PAS-derived CA was an air-side mass transfer coefficient (kA), implying the necessity of spiking depuration chemicals (DCs) because this parameter is strongly related with meteorological conditions. Uncertainty in partition coefficients (KPSM-A or KOA) influences PAS-derived CA to a greater extent with regard to lower KPSM-A chemicals. Also, the PAS-derived CA has an uncertainty range of a half level to a 3-fold higher level of the calculated one. This work is expected to establish solid grounds for the improvement of field measurement technique of HOCs.

  8. Amelioration of the reactive nitrogen flux calculation by a day/night separation in weekly mean air concentration measurements

    NASA Astrophysics Data System (ADS)

    Hayashi, Kentaro; Matsuda, Kazuhide; Ono, Keisuke; Tokida, Takeshi; Hasegawa, Toshihiro

    2013-11-01

    The low time resolution of air concentration data of atmospheric deposition in regional monitoring networks makes it difficult to estimate fluxes between the land and the atmosphere. The present study was an evaluation of the effects of day/night separation for a low time resolution of air concentration measurements (i.e., weekly mean) for the estimation of reactive nitrogen fluxes. The target chemical species included reactive nitrogen primarily ammonia (NH3) and nitric acid gas (HNO3) and secondarily nitrous acid gas, particulate ammonium, and particulate nitrate in addition to sulfur dioxide (SO2) as a reference. Monitoring was conducted for one year at a single-crop rice paddy field in central Japan. The study period was divided into the cropping and fallow seasons, which were characterized by rice plants or a drained bare soil surface, respectively. The filter-pack method was applied to measure the weekly mean air concentrations with day/night separation for the target species at two heights (6 and 2 m above the ground surface). Both an inferential and a gradient method were applied to calculate the deposition and exchange fluxes, respectively. The day/night separation in a weekly sampling protocol, on average, reduced the underestimation of HNO3 fluxes for the inferential method by 15.2% ± 6.8% and 8.2% ± 6.1% in the cropping and fallow seasons, respectively, and reduced the overestimation of NH3 fluxes for the gradient method by 121% ± 128% in the cropping season. The fluxes calculated using the inferential method agreed relatively well with those calculated using the gradient method for HNO3 and SO2. The use of single-height measurements for air concentrations with day/night separation and flux calculations using the inferential method are recommended as an appropriate way to enhance the quality in calculated fluxes while simultaneously suppress the increase in labor cost.

  9. Can changing the timing of outdoor air intake reduce indoor concentrations of traffic-related pollutants in schools?

    PubMed

    MacNeill, M; Dobbin, N; St-Jean, M; Wallace, L; Marro, L; Shin, T; You, H; Kulka, R; Allen, R W; Wheeler, A J

    2016-10-01

    Traffic emissions have been associated with a wide range of adverse health effects. Many schools are situated close to major roads, and as children spend much of their day in school, methods to reduce traffic-related air pollutant concentrations in the school environment are warranted. One promising method to reduce pollutant concentrations in schools is to alter the timing of the ventilation so that high ventilation time periods do not correspond to rush hour traffic. Health Canada, in collaboration with the Ottawa-Carleton District School Board, tested the effect of this action by collecting traffic-related air pollution data from four schools in Ottawa, Canada, during October and November 2013. A baseline and intervention period was assessed in each school. There were statistically significant (P < 0.05) reductions in concentrations of most of the pollutants measured at the two late-start (9 AM start) schools, after adjusting for outdoor concentrations and the absolute indoor-outdoor temperature difference. The intervention at the early-start (8 AM start) schools did not have significant reductions in pollutant concentrations. Based on these findings, changing the timing of the ventilation may be a cost-effective mechanism of reducing traffic-related pollutants in late-start schools located near major roads.

  10. Ambient concentrations and personal exposure to polycyclic aromatic hydrocarbons (PAH) in an urban community with mixed sources of air pollution

    PubMed Central

    ZHU, XIANLEI; FAN, ZHIHUA (TINA); WU, XIANGMEI; JUNG, KYUNG HWA; OHMAN-STRICKLAND, PAMELA; BONANNO, LINDA J.; LIOY, PAUL J.

    2014-01-01

    Assessment of the health risks resulting from exposure to ambient polycyclic aromatic hydrocarbons (PAH) is limited by a lack of environmental exposure data among the general population. This study characterized personal exposure and ambient concentrations of PAH in the Village of Waterfront South (WFS), an urban community with many mixed sources of air toxics in Camden, New Jersey, and CopeWood/Davis Streets (CDS), an urban reference area located ~1 mile east of WFS. A total of 54 and 53 participants were recruited from non-smoking households in WFS and CDS, respectively. In all, 24-h personal and ambient air samples were collected simultaneously in both areas on weekdays and weekends during summer and winter. The ambient PAH concentrations in WFS were either significantly higher than or comparable to those in CDS, indicating the significant impact of local sources on PAH pollution in WFS. Analysis of diagnostic ratios and correlation suggested that diesel truck traffic, municipal waste combustion and industrial combustion were the major sources in WFS. In such an area, ambient air pollution contributed significantly to personal PAH exposure, explaining 44–96% of variability in personal concentrations. This study provides valuable data for examining the impact of local ambient PAH pollution on personal exposure and therefore potential health risks associated with environmental PAH pollution. PMID:21364704

  11. Determination of benzene, toluene and xylene concentration in humid air using differential ion mobility spectrometry and partial least squares regression.

    PubMed

    Maziejuk, M; Szczurek, A; Maciejewska, M; Pietrucha, T; Szyposzyńska, M

    2016-05-15

    Benzene, toluene and xylene (BTX compounds) are chemicals of greatest concern due to their impact on humans and the environment. In many cases, quantitative information about each of these compounds is required. Continuous, fast-response analysis, performed on site would be desired for this purpose. Several methods have been developed to detect and quantify these compounds in this way. Methods vary considerably in sensitivity, accuracy, ease of use and cost-effectiveness. The aim of this work is to show that differential ion mobility spectrometry (DMS) may be applied for determining concentration of BTX compounds in humid air. We demonstrate, this goal is achievable by applying multivariate analysis of the measurement data using partial least squares (PLS) regression. The approach was tested at low concentrations of these compounds in the range of 5-20 ppm and for air humidity in a range 0-12 g/kg. These conditions correspond to the foreseeable application of the developed approach in occupational health and safety measurements. The average concentration assessment error was about 1 ppm for each: benzene, toluene and xylene. We also successfully determined water vapor content in air. The error achieved was 0.2 g/kg. The obtained results are very promising regarding further development of DMS technique as well as its application.

  12. Investigation of indoor air volatile organic compounds concentration levels in dental settings and some related methodological issues.

    PubMed

    Santarsiero, Anna; Fuselli, Sergio; Piermattei, Alessandro; Morlino, Roberta; De Blasio, Giorgia; De Felice, Marco; Ortolani, Emanuela

    2009-01-01

    The assessment of indoor air volatile organic compounds (VOCs) concentration levels in dental settings has a big health relevance for the potentially massive occupational exposure to a lot of diverse contaminants. The comparison of the VOCs profile relative to indoor conditions and to the corresponding outdoor concentrations, as well as the discovery of possible correlations between specific dental activities and VOCs concentration variations are of utmost importance for offering a reliable characterization of risk for dentists and dental staff health. In this study we review the most relevant environmental studies addressing the VOCs contamination level in dental settings. We analyze the methodological problems this kind of study must face and we report preliminary results of an indoor air investigation, carried out at dental hospital in Italy, the "Ospedale odontoiatrico George Eastman" of Rome, in which general lines for the analysis of dental settings in environmental terms are sketched. The aim of this work is to identify the kind of problems a typical enclosed (non-industrial) environment indoor air investigation has to cope with by means of the analysis of a case study.

  13. Production, composition, and oxidative stability of milk highly enriched in polyunsaturated fatty acids from dairy cows fed alfalfa protein concentrate or supplemental vitamin E.

    PubMed

    Fauteux, M-C; Gervais, R; Rico, D E; Lebeuf, Y; Chouinard, P Y

    2016-06-01

    Given its elevated content of carotenoids, alfalfa protein concentrates (APC) have the potential to prevent oxidation of milk enriched in polyunsaturated fatty acids. The effects of feeding APC or supplemental vitamin E on production, composition, and oxidative stability of milk enriched in polyunsaturated fatty acids were evaluated using 6 lactating Holstein cows (224±18d in milk) in a replicated 3×3 Latin square (21-d periods, 14d for adaptation). Treatment diets contained (dry matter basis) (1) 9% soybean meal (control, CTL); (2) 9% soybean meal + 300 IU of vitamin E/kg (VitE treatment); or (3) 9% APC (APC treatment). Cows received a continuous abomasal infusion of 450g/d of linseed oil. As a result, milk fat content of cis-9,cis-12 18:2 increased from 1.08±0.13 to 3.9±0.40% (mean ± SD), whereas cis-9,cis-12,cis-15 18:3 increased from 0.40±0.04 to 14.27±1.81% during the experimental period compared with the pretrial period. Milk yield tended to be higher for APC (14.7kg/d) compared with CTL (13.4kg/d), and was greater than that for VitE (13.0kg/d). Protein yield was higher in cows fed APC (518g/d) compared with VitE (445g/d) but was not different from that in cows fed CTL (483g/d). These effects resulted in improved milk N efficiency in cows fed APC (26.1% of N intake secreted in milk) compared with CTL (23.0%) and VitE (22.9%). Feeding APC increased milk fat content of lutein (252μg/g) compared with CTL (204μg/g) and VitE (190μg/g). Milk fat content of vitamin E was higher for APC (34.5μg/g) compared with CTL (19.0μg/g) and tended to be lower than that with VitE (44.9μg/g). Redox potential of fresh milk from cows fed APC (152mV) was similar to that of VitE (144mV), but lower than that of CTL (189mV). Treatments had no effect on fresh milk contents of dissolved oxygen (8.1±1.5mg/L), and conjugated diene hydroperoxides (2.7±0.5mmol/L). The concentrations of volatile lipid oxidation products (propanal, hexanal, hept-cis-4-enal, 1-octen-3-one) tended

  14. Production, composition, and oxidative stability of milk highly enriched in polyunsaturated fatty acids from dairy cows fed alfalfa protein concentrate or supplemental vitamin E.

    PubMed

    Fauteux, M-C; Gervais, R; Rico, D E; Lebeuf, Y; Chouinard, P Y

    2016-06-01

    Given its elevated content of carotenoids, alfalfa protein concentrates (APC) have the potential to prevent oxidation of milk enriched in polyunsaturated fatty acids. The effects of feeding APC or supplemental vitamin E on production, composition, and oxidative stability of milk enriched in polyunsaturated fatty acids were evaluated using 6 lactating Holstein cows (224±18d in milk) in a replicated 3×3 Latin square (21-d periods, 14d for adaptation). Treatment diets contained (dry matter basis) (1) 9% soybean meal (control, CTL); (2) 9% soybean meal + 300 IU of vitamin E/kg (VitE treatment); or (3) 9% APC (APC treatment). Cows received a continuous abomasal infusion of 450g/d of linseed oil. As a result, milk fat content of cis-9,cis-12 18:2 increased from 1.08±0.13 to 3.9±0.40% (mean ± SD), whereas cis-9,cis-12,cis-15 18:3 increased from 0.40±0.04 to 14.27±1.81% during the experimental period compared with the pretrial period. Milk yield tended to be higher for APC (14.7kg/d) compared with CTL (13.4kg/d), and was greater than that for VitE (13.0kg/d). Protein yield was higher in cows fed APC (518g/d) compared with VitE (445g/d) but was not different from that in cows fed CTL (483g/d). These effects resulted in improved milk N efficiency in cows fed APC (26.1% of N intake secreted in milk) compared with CTL (23.0%) and VitE (22.9%). Feeding APC increased milk fat content of lutein (252μg/g) compared with CTL (204μg/g) and VitE (190μg/g). Milk fat content of vitamin E was higher for APC (34.5μg/g) compared with CTL (19.0μg/g) and tended to be lower than that with VitE (44.9μg/g). Redox potential of fresh milk from cows fed APC (152mV) was similar to that of VitE (144mV), but lower than that of CTL (189mV). Treatments had no effect on fresh milk contents of dissolved oxygen (8.1±1.5mg/L), and conjugated diene hydroperoxides (2.7±0.5mmol/L). The concentrations of volatile lipid oxidation products (propanal, hexanal, hept-cis-4-enal, 1-octen-3-one) tended

  15. Short-term temperature-dependent air-surface exchange and atmospheric concentrations of polychlorinated naphthalenes and organochlorine pesticides

    SciTech Connect

    Lee, R.G.M.; Burnett, V.; Harner, T.; Jones, K.C.

    2000-02-01

    Atmospheric concentrations of five organochlorine (OC) pesticides, some of which have been banned for a number of years, and polychlorinated naphthalenes (PCNs) were measured at a U.K. site over periods of 6 h for 7 days resulting in 28 samples. Mean concentrations of the pesticides were {alpha}-HCH 90 pg m{sup {minus}3}, {gamma}-HCH 500, {rho},{rho}{prime}-DDE 8, dieldrin 63, endrin 22, and HCB 39. PCN mean homologue concentrations were {sub 3}CNs 67 pg m{sup {minus}3}, {sub 4}CNs 78, {sub 5}CNs 5, {sub 6}CNs 0.6, {sub 7}CNs 0.6, and {Sigma}PCNs 152. TEQ concentrations for those PCNs ascribed TEF values ranged between 0.36 and 3.6 fg m{sup {minus}3} which corresponds to {approximately}3.0--30% of the TEQ concentrations of PCDD/Fs at the same site. All the compounds measured, except HCB, exhibited a strong temperature-dependent diurnal cycling. Results from Clausius-Clapeyron plots show that pesticide concentrations were controlled by temperature-driven air-surface recycling throughout the first 5 days when stable atmospheric conditions were dominant, while during the last 2 days advection became more influential as more unstable and cooler weather started to influence the site. PCN concentrations were controlled primarily by a mixture of recycling and advection throughout the first 5 days and then by advection in the final 2 days, suggesting that there are ongoing emissions from diffuse point sources of PCNs into the U.K. atmosphere. This study provides further evidence of the rapid air-surface exchange of semivolatile organic compounds (SOCs) and shows how different factors alone or in combination can produce rapid changes in the atmospheric concentrations of past and present SOCs.

  16. Exposure to concentrated coarse air pollution particles causes mild cardiopulmonary effects in young healthy adults

    EPA Science Inventory

    Rationale: There is ample epidemiological and toxicological evidence that exposure to fme air pollution particles (PM2.5), which are primarily derived from combustion processes, can result in increased mortality and morbidity. There is less certainty as to the contribution of coa...

  17. Vascular Effects of a Subchronic Inhalation Exposure to Concentrated Ambient Air Particles in Atherosclerosis Susceptible Mice

    EPA Science Inventory

    Numerous studies have reported the adverse effects of particulate air pollution on cardiovascular function and disease. The causal physiochemical properties of particles and their mechanisms of action/injury remain unknown. This study examined the vascular effects in 15 wk old ma...

  18. Development and Evaluation of Land-Use Regression Models Using Modeled Air Quality Concentrations

    EPA Science Inventory

    Abstract Land-use regression (LUR) models have emerged as a preferred methodology for estimating individual exposure to ambient air pollution in epidemiologic studies in absence of subject-specific measurements. Although there is a growing literature focused on LUR evaluation, fu...

  19. A modeling framework for characterizing near-road air pollutant concentration at community scales

    EPA Science Inventory

    In this study, we combine information from transportation network, traffic emissions, and dispersion model to develop a framework to inform exposure estimates for traffic-related air pollutants (TRAPs) with a high spatial resolution. A Research LINE source dispersion model (R-LIN...

  20. Biological monitoring of dichloropropene: Air concentrations, urinary metabolite, and renal enzyme excretion

    SciTech Connect

    Osterloh, J.D.; Wang, R.; Schneider, F.; Maddy, K. )

    1989-07-01

    Fifteen applicators of dichloropropene (DCP) were studied for personal air exposure to DCP, excretion of the metabolite of DCP (3CNAC), and excretion of the renal tubular enzyme, N-acetyl glucosaminidase (NAG). Each was studied for four 6-8 h consecutive intervals following baseline determinations of 3CNAC and NAG excretion. In accord with pilot data, 24-h urinary excretion of 3CNAC (mg) correlated well with exposure product for DCP (min exposed.mg/m{sup 3}), r = 0.854, p less than .001. A more precise correlation of the air exposure product with urinary excretion of 3CNAC was discerned by using the morning urine after the previous day of exposure (micrograms/mg of creatinine), r = 0.914, p less than .001. Four workers had clinically elevated activity of NAG (greater than 4 mU/mg creatinine) in any of their urine collections after baseline. Nine workers showed greater than 25% increases in NAG excretion when compared to baseline. Dichloropropene air exposure products of greater than 700 mg.min/m{sup 3} or excretion of greater than 1.5 mg 3CNAC/d distinguished abnormally high daily excretion of NAG. These data demonstrate a firm positive relationship between air exposure and internal exposure, and a possible subclinical nephrotoxic effect in DCP workers.

  1. Selenium concentration and speciation in biofortified flour and bread: Retention of selenium during grain biofortification, processing and production of Se-enriched food.

    PubMed

    Hart, D J; Fairweather-Tait, S J; Broadley, M R; Dickinson, S J; Foot, I; Knott, P; McGrath, S P; Mowat, H; Norman, K; Scott, P R; Stroud, J L; Tucker, M; White, P J; Zhao, F J; Hurst, R

    2011-06-15

    The retention and speciation of selenium in flour and bread was determined following experimental applications of selenium fertilisers to a high-yielding UK wheat crop. Flour and bread were produced using standard commercial practices. Total selenium was measured using inductively coupled plasma-mass spectrometry (ICP-MS) and the profile of selenium species in the flour and bread were determined using high performance liquid chromatography (HPLC) ICP-MS. The selenium concentration of flour ranged from 30ng/g in white flour and 35ng/g in wholemeal flour from untreated plots up to >1800ng/g in white and >2200ng/g in wholemeal flour processed from grain treated with selenium (as selenate) at the highest application rate of 100g/ha. The relationship between the amount of selenium applied to the crop and the amount of selenium in flour and bread was approximately linear, indicating minimal loss of Se during grain processing and bread production. On average, application of selenium at 10g/ha increased total selenium in white and wholemeal bread by 155 and 185ng/g, respectively, equivalent to 6.4 and 7.1μg selenium per average slice of white and wholemeal bread, respectively. Selenomethionine accounted for 65-87% of total extractable selenium species in Se-enriched flour and bread; selenocysteine, Se-methylselenocysteine selenite and selenate were also detected. Controlled agronomic biofortification of wheat crops for flour and bread production could provide an appropriate strategy to increase the intake of bioavailable selenium.

  2. Concentrations of vehicle-related air pollutants in an urban parking garage.

    PubMed

    Kim, Sung R; Dominici, Francesca; Buckley, Timothy J

    2007-11-01

    There is growing evidence that traffic-related air pollution poses a public health threat, yet the dynamics of human exposure are not well understood. The urban parking garage is a microenvironment that is of concern but has not been characterized. Using time-resolved measurement methods, we evaluated air toxics levels within an urban parking garage and assessed the influence of vehicle activity and type on their levels. Carbon monoxide (CO) and particle-bound polycyclic aromatic hydrocarbons (pPAH) were measured with direct-reading instruments. Volatile organic compounds (VOCs) were measured in 30 min intervals using a sorbent tube loaded sequential sampler. Vehicle volume and type were evaluated by video recording. Sampling was conducted from June 24 to July 17, 2002. We observed garage traffic median volumes of 71 counts/h on weekdays and 6 counts/h on weekends. The 12-fold reduction in traffic volume from weekday to weekend corresponded with a decrease in median air pollution that varied from a minimum 2- (CO) to a maximum 7 (pPAH)-fold. The actual 30-min median weekday and weekend values were: CO--2.6/1.2 ppm; pPAH--19/2.6 ng/m(3); 1,3-butadiene-0.5/0.2 microg/m(3), MTBE-7.4/0.4 microg/m(3); and benzene-2.7/0.3 microg/m(3). The influence of traffic was quantified using longitudinal models. The pollutant coefficients provide an indication of the average air pollution vehicle source contribution and ranged from 0.31 (CO) to 1.08 (pPAH) percent increase/vehicle count. For some pollutants, a slightly higher (0.5-0.6%) coefficient was observed for light-trucks relative to cars. This study has public health relevance in providing a unique assessment of air pollution levels and source contribution for the urban parking garage.

  3. Response of ozone to changes in hydrocarbon and nitrogen oxide concentrations in outdoor smog chambers filled with Los Angeles air

    NASA Astrophysics Data System (ADS)

    Kelly, Nelson A.; Gunst, Richard F.

    During the summer portion of the 1987 Southern California Air Quality Study (SCAQS), outdoor smog chamber experiments were performed on Los Angeles air to determine the response of maximum ozone levels, O 3(max), to changes in the initial concentrations of hydrocarbons, HC, and nitrogen oxides, NO x. These captive-air experiments were conducted in downtown Los Angeles and in the downwind suburb of Claremont. Typically, eight chambers were filled with LA air in the morning. In some chambers the initial HC and/or NO x concentrations were changed by 25% to 50% by adding various combinations of a mixture of HC, clean air, or NO x. The O 3 concentration in each chamber was monitored throughout the day to determine O 3(max). An empirical mathematical model for O 3(max) was developed from regression fits to the initial HC and NO x concentrations and to the average daily temperature at both sites. This is the first time that a mathematical expression for the O 3-precursor relationship and the positive effect of temperature on O 3(max) have been quantified using captive-air experiments. An ozone isopleth diagram prepared from the empirical model was qualitatively similar to those prepared from photochemical mechanisms. This constitutes the first solely empirical corroboration of the O 3 contour shape for Los Angeles. To comply with the Federal Ozone Standard in LA, O 3(max) must be reduced by approximately 50%. Several strategies for reducing O 3(max) by 50% were evaluated using the empirical model. For the average initial conditions that we measured in LA, the most efficient strategy is one that reduces HC by 55-75%, depending on the ambient HC/NO x ratio. Any accompanying reduction in NO x would be counter-productive to the benefits of HC reductions. In fact, reducing HC and NO x simultaneously requires larger percentage reductions for both than the reduction required when HC alone is reduced. The HC-reduction strategy is the most efficient on average, but no single

  4. BIFoR FACE: A ten-year Free-Air Carbon Dioxide Enrichment (FACE) Experiment in Old Growth Deciduous English Woodland

    NASA Astrophysics Data System (ADS)

    Thomas, R. M.; MacKenzie, A. R.; Ellsworth, D.; Hemming, D.; Crous, K.; Pope, F.; Blaen, P.; Poynter, A.; Hamilton, L.; Blenkhorn, D.; Jarvis-Rouse, F.

    2015-12-01

    The Birmingham Institute of Forest research (BIFoR) will perform fundamental physical, biological, ecological, social and cultural research of direct relevance to forested landscapes worldwide. A core platform for BIFoR to study the ten-year response of a mature temperate deciduous forest ecosystem to against a large step-change in atmospheric [CO2] is the BIFoR Free-Air Carbon Dioxide Enrichment (FACE) experiment. BIFoR FACE is being established in Mill Haft, a mature (~150 year-old) oak (Quercus robur) and hazel (Corylus avellana) coppice-with-standards woodland in central England. The facility will enable elevated CO2 (eCO2) treatments to be introduced in 30 m diameter rings (3 treatment and 6 control plots), commencing in spring 2016. Under eCO2 conditions primary research questions will investigate carbon uptake and storage, corresponding nutrient limitations, and biodiversity and ecosystem responses. As well as describing the facility and experimental design, we present baseline data collected throughout 2015, prior to fumigation. These data include: biophysical tree properties; atmospheric CO2/H2O fluxes; airborne and ground laser scatterometry; leaf area index; geophysical survey data; phenology camera derivatives; soil and water chemical and physical properties; and invertebrate surveys. Data from an intensive campaign conducted during august 2015 are also shown, including in- and above- canopy characterisation of biogenic VOCs using a Proton Transfer Reaction Mass Spectrometer, aerosol loading including bioaerosols, and enhanced atmospheric chemistry. Further campaign results are presented from leaf level photosynthetic carbon-dioxide response curve (A/Ci) performed at different canopy heights on oak trees, and on the dominant understory species - hazel and sycamore (Acer pseudoplatinus) across the site. BIFoR FACE is an exciting new international facility for forest science - ideas for collaborations are encouraged. Please see http

  5. Does free-air carbon dioxide enrichment affect photochemical energy use by evergreen trees in different seasons? A chlorophyll fluorescence study of mature loblolly pine

    SciTech Connect

    Hymus, G.J.; Ellsworth, D.S.; Baker, N.R.; Long, S.P.

    1999-08-01

    Previous studies of the effects of growth at elevated CO{sup 2} on energy partitioning in the photosynthetic apparatus have produced conflicting results. The hypothesis was developed and tested that elevated CO{sub 2} increases photochemical energy use when there is a high demand for assimilates and decreases usage when demand is low. Modulated chlorophyll a fluorescence and leaf gas exchange were measured on needles at the tope of a mature, 12-m loblolly pine (Pinus taeda L.l) forest. Trees were exposed to ambient CO{sub 2} or ambient plus 20 Pa CO{sub 2} using free-air CO{sub 2} enrichment. During April and August, periods of shoot growth, light-saturated photo-synthesis and linear electron transport were increased by elevated CO{sub 2}. In November, when growth had ceased but temperatures were still moderate, CO{sub 2} treatment had no significant effect on linear electron transport. In February, when low temperatures were likely to inhibit translocation, CO{sub 2} treatment caused a significant decrease in linear electron transport. This coincided with a slower recovery of the maximum photosystem II efficiency on transfer of needles to the shade, indicating that growth in elevated CO{sub 2} induced a more persistent photoinhibition. Both the summer increase and the winter decrease in linear electron transport in elevated CO{sub 2} resulted from a change in photochemical quenching, not in the efficiency of energy transfer within the photosystem II antenna. There was no evidence of any effect of CO{sub 2} on photochemical energy sinks other than carbon metabolism. Their results suggest that elevated CO{sub 2} may increase the effects of winter stress on evergreen foliage.

  6. Soil and water warming accelerates phenology and down-regulation of leaf photosynthesis of rice plants grown under free-air CO2 enrichment (FACE).

    PubMed

    Adachi, Minaco; Hasegawa, Toshihiro; Fukayama, Hiroshi; Tokida, Takeshi; Sakai, Hidemitsu; Matsunami, Toshinori; Nakamura, Hirofumi; Sameshima, Ryoji; Okada, Masumi

    2014-02-01

    To enable prediction of future rice production in a changing climate, we need to understand the interactive effects of temperature and elevated [CO2] (E[CO2]). We therefore examined if the effect of E[CO2] on the light-saturated leaf photosynthetic rate (Asat) was affected by soil and water temperature (NT, normal; ET, elevated) under open-field conditions at the rice free-air CO2 enrichment (FACE) facility in Shizukuishi, Japan, in 2007 and 2008. Season-long E[CO2] (+200 µmol mol(-1)) increased Asat by 26%, when averaged over two years, temperature regimes and growth stages. The effect of ET (+2°C) on Asat was not significant at active tillering and heading, but became negative and significant at mid-grain filling; Asat in E[CO2]-ET was higher than in ambient [CO2] (A[CO2])-NT by only 4%. Photosynthetic down-regulation at E[CO2] also became apparent at mid-grain filling; Asat compared at the same [CO2] in the leaf cuvette was significantly lower in plants grown in E[CO2] than in those grown in A[CO2]. The additive effects of E[CO2] and ET decreased Asat by 23% compared with that of A[CO2]-NT plants. Although total crop nitrogen (N) uptake was increased by ET, N allocation to the leaves and to Rubisco was reduced under ET and E[CO2] at mid-grain filling, which resulted in a significant decrease (32%) in the maximum rate of ribulose-1,5-bisphosphate carboxylation on a leaf area basis. Because the change in N allocation was associated with the accelerated phenology in E[CO2]-ET plants, we conclude that soil and water warming accelerates photosynthetic down-regulation at E[CO2].

  7. Soil and water warming accelerates phenology and down-regulation of leaf photosynthesis of rice plants grown under free-air CO2 enrichment (FACE).

    PubMed

    Adachi, Minaco; Hasegawa, Toshihiro; Fukayama, Hiroshi; Tokida, Takeshi; Sakai, Hidemitsu; Matsunami, Toshinori; Nakamura, Hirofumi; Sameshima, Ryoji; Okada, Masumi

    2014-02-01

    To enable prediction of future rice production in a changing climate, we need to understand the interactive effects of temperature and elevated [CO2] (E[CO2]). We therefore examined if the effect of E[CO2] on the light-saturated leaf photosynthetic rate (Asat) was affected by soil and water temperature (NT, normal; ET, elevated) under open-field conditions at the rice free-air CO2 enrichment (FACE) facility in Shizukuishi, Japan, in 2007 and 2008. Season-long E[CO2] (+200 µmol mol(-1)) increased Asat by 26%, when averaged over two years, temperature regimes and growth stages. The effect of ET (+2°C) on Asat was not significant at active tillering and heading, but became negative and significant at mid-grain filling; Asat in E[CO2]-ET was higher than in ambient [CO2] (A[CO2])-NT by only 4%. Photosynthetic down-regulation at E[CO2] also became apparent at mid-grain filling; Asat compared at the same [CO2] in the leaf cuvette was significantly lower in plants grown in E[CO2] than in those grown in A[CO2]. The additive effects of E[CO2] and ET decreased Asat by 23% compared with that of A[CO2]-NT plants. Although total crop nitrogen (N) uptake was increased by ET, N allocation to the leaves and to Rubisco was reduced under ET and E[CO2] at mid-grain filling, which resulted in a significant decrease (32%) in the maximum rate of ribulose-1,5-bisphosphate carboxylation on a leaf area basis. Because the change in N allocation was associated with the accelerated phenology in E[CO2]-ET plants, we conclude that soil and water warming accelerates photosynthetic down-regulation at E[CO2]. PMID:24406632

  8. THE PHOTOSYNTHETIC RESPONSE OF THE PERENNIAL RYEGRASS (LOLIUM PERENNE) IN ITS FIFTH YEAR OF FREE-AIR CO{sub 2} ENRICHMENT (FACE) AT ESCHIKON, SWITZERLAND

    SciTech Connect

    ANDERSON,J.P.; LONG,STEPHEN,P.; WILLIAMS,J.

    1998-12-31

    Stands of Ryegrass (Lolium perenne L. cv.Bastion) were grown in the field at ambient or elevated (600 {micro}mol mol{sup {minus}1}) [CO{sub 2}], high (560 kg Ha{sup {minus}1} y{sup {minus}1}) or low (140 kg Ha{sup {minus}1} y{sup {minus}1}) nitrogen addition and were harvested five times a year during the growing season. The plants were sown during 1992, additional plots being sown during 1995. These were in their fifth year and second year of growth respectively. Exposure to elevated [CO{sub 2}] was carried out with a Free-Air CO{sub 2} Enrichment (FACE) system which provides the most realistic system of fumigation currently available. Elevated [CO{sub 2}] increased diurnal CO{sub 2} uptake by between 40 to 83% while reducing stomatal conductance by between 1 and 38% in all of the 1992 grown plants measured at high [CO{sub 2}]. Analysis of the A/c{sub i} response of 1992 grown plants showed no acclimation of the photosynthetic apparatus in response to elevated [CO{sub 2}]--both V{sub c,max} (a measure of the maximum in vivo rate of carboxylation) and J{sub max} (a measure of the maximum capacity for the regeneration of RuBP) showed no significant change during any of the periods of regrowth. In contrast the leaves of 1995 grown plants, appeared to be experiencing an acclimatory change in their photosynthetic apparatus in response to elevated [CO{sub 2}]. However, this negative response seemed to be removed directly after a harvest when the source:sink balance had increased. The apparent lack of an acclimatory response after almost 5 years of growth at elevated [CO{sub 2}], suggests that L. perenne may be close to achieving the appropriate photosynthetic adjustments which would allow it to attain a significantly higher photosynthetic potential.

  9. The photosynthetic response of the perennial ryegrass (Lolium perenne) in its fifth year of free-air CO(sub 2) enrichment (FACE) at Eschikon, Switzerland

    SciTech Connect

    Anderson, J.P.; Long, S.P.; Williams, J.

    1998-12-31

    Stands of Ryegrass (Lolium perenne L. cv.Bastion) were grown in the field at ambient or elevated (600 {micro}mol mol{sup {minus}1}) [CO{sub 2}], high (560 kg Ha{sup {minus}1} y{sup {minus}1}) or low (140 kg Ha{sup {minus}1} y{sup {minus}1}) nitrogen addition and were harvested five times a year during the growing season. The plants were sown during 1992, additional plots being sown during 1995. These were in their fifth year and second year of growth respectively. Exposure to elevated [CO{sub 2}] was carried out with a Free-Air CO{sub 2} Enrichment (FACE) system which provides the most realistic system of fumigation currently available. Elevated [CO{sub 2}] increased diurnal CO{sub 2} uptake by between 40 to 83% while reducing stomatal conductance by between 1 and 38% in all of the 1992 grown plants measured at high [CO{sub 2}]. Analysis of the A/c{sub i} response of 1992 grown plants showed no acclimation of the photosynthetic apparatus in response to elevated [CO{sub 2}] - both V{sub c,max} (a measure of the maximum in vivo rate of carboxylation) and J{sub max} (a measure of the maximum capacity for the regeneration of RuBP) showed no significant change during any of the periods of regrowth. In contrast the leaves of 1995 grown plants, appeared to be experiencing an acclimatory change in their photosynthetic apparatus in response to elevated [CO{sub 2}]. However, this negative response seemed to be removed directly after a harvest when the source:sink balance had increased. The apparent lack of an acclimatory response after almost 5 years of growth at elevated [CO{sub 2}], suggests that L. perenne may be close to achieving the appropriate photosynthetic adjustments which would allow it to attain a significantly higher photosynthetic potential.

  10. Spatial and Temporal Effects of Free-Air CO2 Enrichment (POPFACE) on Leaf Growth, Cell Expansion, and Cell Production in a Closed Canopy of Poplar1

    PubMed Central

    Taylor, Gail; Tricker, Penny J.; Zhang, Fang Z.; Alston, Victoria J.; Miglietta, Franco; Kuzminsky, Elena

    2003-01-01

    Leaf expansion in the fast-growing tree, Populus × euramericana was stimulated by elevated [CO2] in a closed-canopy forest plantation, exposed using a free air CO2 enrichment technique enabling long-term experimentation in field conditions. The effects of elevated [CO2] over time were characterized and related to the leaf plastochron index (LPI), and showed that leaf expansion was stimulated at very early (LPI, 0–3) and late (LPI, 6–8) stages in development. Early and late effects of elevated [CO2] were largely the result of increased cell expansion and increased cell production, respectively. Spatial effects of elevated [CO2] were also marked and increased final leaf size resulted from an effect on leaf area, but not leaf length, demonstrating changed leaf shape in response to [CO2]. Leaves exhibited a basipetal gradient of leaf development, investigated by defining seven interveinal areas, with growth ceasing first at the leaf tip. Interestingly, and in contrast to other reports, no spatial differences in epidermal cell size were apparent across the lamina, whereas a clear basipetal gradient in cell production rate was found. These data suggest that the rate and timing of cell production was more important in determining leaf shape, given the constant cell size across the leaf lamina. The effect of elevated [CO2] imposed on this developmental gradient suggested that leaf cell production continued longer in elevated [CO2] and that basal increases in cell production rate were also more important than altered cell expansion for increased final leaf size and altered leaf shape in elevated [CO2]. PMID:12529526

  11. Comprehensive ecosystem model-experiment synthesis using multiple datasets at two temperate forest free-air CO2 enrichment experiments: model performance and compensating biases

    SciTech Connect

    Walker, Anthony P; Hanson, Paul J; DeKauwe, Martin G; Medlyn, Belinda; Zaehle, S; Asao, Shinichi; Dietze, Michael; Hickler, Thomas; Huntinford, Chris; Iversen, Colleen M; Jain, Atul; Lomas, Mark; Luo, Yiqi; McCarthy, Heather R; Parton, William; Prentice, I. Collin; Thornton, Peter E; Wang, Shusen; Wang, Yingping; Warlind, David; Weng, Ensheng; Warren, Jeffrey; Woodward, F. Ian; Oren, Ram; Norby, Richard J

    2014-01-01

    Free Air CO2 Enrichment (FACE) experiments provide a remarkable wealth of data to test the sensitivities of terrestrial ecosystem models (TEMs). In this study, a broad set of 11 TEMs were compared to 22 years of data from two contrasting FACE experiments in temperate forests of the south eastern US the evergreen Duke Forest and the deciduous Oak Ridge forest. We evaluated the models' ability to reproduce observed net primary productivity (NPP), transpiration and Leaf Area index (LAI) in ambient CO2 treatments. Encouragingly, many models simulated annual NPP and transpiration within observed uncertainty. Daily transpiration model errors were often related to errors in leaf area phenology and peak LAI. Our analysis demonstrates that the simulation of LAI often drives the simulation of transpiration and hence there is a need to adopt the most appropriate of hypothesis driven methods to simulate and predict LAI. Of the three competing hypotheses determining peak LAI (1) optimisation to maximise carbon export, (2) increasing SLA with canopy depth and (3) the pipe model the pipe model produced LAI closest to the observations. Modelled phenology was either prescribed or based on broader empirical calibrations to climate. In some cases, simulation accuracy was achieved through compensating biases in component variables. For example, NPP accuracy was sometimes achieved with counter-balancing biases in nitrogen use efficiency and nitrogen uptake. Combined analysis of parallel measurements aides the identification of offsetting biases; without which over-confidence in model abilities to predict ecosystem function may emerge, potentially leading to erroneous predictions of change under future climates.

  12. The GIS-based SafeAirView software for the concentration assessment of radioactive pollutants after an accidental release.

    PubMed

    Canepa, Elisa; D'Alberti, Francesco; D'Amati, Francesco; Triacchini, Giuseppe

    2007-02-01

    The European Commission Joint Research Centre (JRC) in Ispra (Italy) has long been running nuclear installations for research purposes. The Nuclear Decommissioning and Facilities Management Unit (NDFM) is responsible for the surveillance of radioactivity levels in nuclear emergency conditions. The NDFM Unit has commissioned the implementation of a specifically developed decision support system, which can be used for quick emergency evaluation in the case of hypothetical accident and for emergency exercises. The requisites were to be a user-friendly software, able to quickly calculate and display values of air and ground radioactive contamination in the complex area around JRC, following an accidental release of radioactive substances from a JRC nuclear research installation. The developed software, named "SafeAirView", is an advanced implementation of GIS technology applied to an existing MS-DOS mode dispersion model, SAFE_AIR (Simulation of Air pollution From Emissions_Above Inhomogeneous Regions). SAFE_AIR is a numerical model which simulates transport, diffusion, and deposition of airborne pollutants emitted in the low atmosphere above complex orography at both local and regional scale, under non-stationary and inhomogeneous emission and meteorological conditions. SafeAirView makes use of user-friendly MS-Windows type interface which drives the dispersion model by a sequential and continuous input-output process, allowing a real time simulation. The GIS environment allows a direct interaction with the territory elements in which the simulation takes place, using data for the JRC Ispra region represented in geo-referenced cartography. Furthermore it offers the possibility to relate concentrations with population distribution and other geo-referenced maps, in a geographic view. Output concentration and deposition patterns can be plotted and/or exported. In spite of the selected specific databases, the SafeAirView software architecture is a general structure

  13. Particle Concentrations and Effectiveness of Free-Standing Air Filters in Bedrooms of Children with Asthma in Detroit, Michigan

    PubMed Central

    Du, Liuliu; Batterman, Stuart; Parker, Edith; Godwin, Christopher; Chin, Jo-Yu; O'Toole, Ashley; Robins, Thomas; Brakefield-Caldwell, Wilma; Lewis, Toby

    2011-01-01

    Asthma can be exacerbated by environmental factors including airborne particulate matter (PM) and environmental tobacco smoke (ETS). We report on a study designed to characterize PM levels and the effectiveness of filters on pollutant exposures of children with asthma. 126 households with an asthmatic child in Detroit, Michigan, were recruited and randomized into control or treatment groups. Both groups received asthma education; the latter also received a free-standing high efficiency air filter placed in the child’s bedroom. Information regarding the home, emission sources, and occupant activities was obtained using surveys administered to the child's caregiver and a household inspection. Over a one-week period, we measured PM, carbon dioxide (CO2), environmental tobacco smoke (ETS) tracers, and air exchange rates (AERs). Filters were installed at midweek. Before filter installation, PM concentrations averaged 28 µg m−3, number concentrations averaged 70,777 and 1,471 L−1 in 0.3–1.0 and 1–5 µm size ranges, respectively, and the median CO2 concentration was 1,018 ppm. ETS tracers were detected in 23 of 38 homes where smoking was unrestricted and occupants included smokers and, when detected, PM concentrations were elevated by an average of 15 µg m−3. Filter use reduced PM concentrations by an average of 69 to 80%. Simulation models representing location conditions show that filter air flow, room volume and AERs are the key parameters affecting PM removal, however, filters can achieve substantial removal in even "worst" case applications. While PM levels in homes with asthmatic children can be high, levels can be dramatically reduced using filters. PMID:21874085

  14. [Air negative ion concentration in different modes of courtyard forests in southern mountainous areas of Jinan, Shandong Province of East China].

    PubMed

    Wang, Xiao-Lei; Li, Chuan-Rong; Xu, Jing-Wei; Hu, Ding-Meng; Zhao, Zhen-Lei; Zhang, Liu-dong

    2013-02-01

    Taking five typical courtyard forests and a non-forest courtyard in southern mountains areas of Jinan as test objects, a synchronous observation was conducted on the air negative ion concentration and related meteorological factors in March-December, 2010. The air negative ion concentration in the test courtyards showed an obvious seasonal variation, being in the order of summer > autumn > spring > winter. The diurnal variation of the air negative ion concentration presented a double peak curve, with the maximum in 10:00 - 11:00 and 16:00 - 17:00 and the minimum around 12:00. The daily air quality was the best at 10:00 and 16:00, and better in afternoon than in the morning. Summer time and garden sketch mode had the best air quality in a year. The mean annual air negative ion and the coefficient of air ion (CI) of the test courtyards were in the order of garden sketch > economic fruit forest > natural afforested forest > flowers and bonsai > farm tourist > non-forest, with the air negative ion concentration being 813, 745, 695, 688, 649, and 570 ions.cm-3, and the CI being 1.22, 1.11, 0.85, 0.84, 0.83, and 0.69, respectively. It could be concluded that garden sketch was the ideal courtyard forest mode. The air negative ion concentration was significantly positively correlated with air temperature and relative humidity, but irrelevant to light intensity.

  15. [The effect of vitamin- and beta-carotene-enriched products on the vitamin A allowance and the concentration of different carotenoids of the blood serum in victims of the accident at the Chernobyl Atomic Electric Power Station].

    PubMed

    Iakushina, L M; Taranova, A G; Pokrovskaia, G R; Shatniuk, L N; Spirichev, V B

    1996-01-01

    The results of clinical trials of efficiency of foods enriched by vitamins and beta-carotene in people suffered from Chernobyl's accident are presented. The level of beta-carotene in clinical diets was the same during trial. Daily consumption of enriched food supplying ingestion of 4-5 mg of beta-carotene increased the level of beta-carotene in serum by 2-4 times. The concentration of total carotenoides in serum was increased by 1.6 times practically at the expense of beta-carotene.

  16. Spatial and seasonal variation in volatile compounds air concentrations in a hemiboreal mixed forest.

    NASA Astrophysics Data System (ADS)

    Noe, Steffen M.; Hüve, Katja; Niinemets, Ülo; Copolovici, Lucian

    2013-04-01

    The seasonal and vertical distribution of ambient biogenic volatile organic compounds (BVOC) concentrations within a hemiboreal forest canopy was investigated over a period of one year. Variability in temporal and spatial terpene concentrations spanned over a wide range. Specially stress related emissions lead to very high ambient concentrations in dry and hot summer months. Seasonal differences in the share of different monoterpenes were found. During summer months, dominance of α-pinene in the lower and of limonene in the upper part of the canopy was observed, both accounting for up to 70 % of the total monoterpene concentration. During wintertime, Δ3-carene was the dominant species, accounting for 60 % of total monoterpene concentration in January. Spatially, the possible sources of biogenic monoterpenes are beside foliage the leaf litter and top soil as well as resins exuding from stems.

  17. Industrial sources influence air concentrations of hydrogen sulfide and sulfur dioxide in rural areas of western Canada.

    PubMed

    Burstyn, Igor; Senthilselvan, Ambikaipakan; Kim, Hyang-Mi; Cherry, Nicola M; Pietroniro, Elise; Waldner, Cheryl

    2007-10-01

    A survey of monthly average concentrations of sulfur dioxide (SO2) and hydrogen sulfide (H2S) at rural locations in western Canada (provinces of Alberta, British Columbia, and Saskatchewan) was conducted in 2001-2002, as part of an epidemiological study of the effects of oil and gas industry emissions on the health of cattle. Repeated measurements were obtained at some months and locations. We aimed to develop statistical models of the effect of oil and gas infrastructure on air concentrations. The regulatory authorities supplied the information on location of the different oil and gas facilities during the study period and, for Alberta, provided data on H2S content of wells and flaring volumes. Linear mixed effects models were used to relate observed concentrations to proximity and type of oil and gas infrastructure. Low concentrations were recorded; the monthly geometric mean was 0.1-0.2 ppb for H2S, and 0.3-1.3 ppb for SO2. Substantial variability between repeated measurements was observed. The precision of the measurement method was 0.005 ppb for both contaminants. There were seasonal trends in the concentrations, but the spatial variability was greater. This was explained, in part, by proximity to oil/gas/bitumen wells and (for SO2) gas plants. Wells within 2 km of monitoring stations had the greatest impact on measured concentrations. For H2S, 8% of between-location variability was explained by proximity to industrial sources of emissions; for SO2 this proportion was 18%. In Alberta, proximity to sour gas wells and flares was associated with elevated H2S concentrations; however, the estimate of the effect of sour gas wells in the immediate vicinity of monitoring stations was unstable. Our study was unable to control for all possible sources of the contaminants. However, the results suggest that oil and gas extraction activities contribute to air pollution in rural areas of western Canada. PMID:17972769

  18. Occupational dimethylformamide exposure. 1. Diffusive sampling of dimethylformamide vapor for determination of time-weighted average concentration in air.

    PubMed

    Yasugi, T; Kawai, T; Mizunuma, K; Horiguchi, S; Iguchi, H; Ikeda, M

    1992-01-01

    A diffusive sampling method with water as absorbent was examined in comparison with 3 conventional methods of diffusive sampling with carbon cloth as absorbent, pumping through National Institute of Occupational Safety and Health (NIOSH) charcoal tubes, and pumping through NIOSH silica gel tubes to measure time-weighted average concentration of dimethylformamide (DMF). DMF vapors of constant concentrations at 3-110 ppm were generated by bubbling air at constant velocities through liquid DMF followed by dilution with fresh air. Both types of diffusive samplers could either absorb or adsorb DMF in proportion to time (0.25-8 h) and concentration (3-58 ppm), except that the DMF adsorbed was below the measurable amount when carbon cloth samplers were exposed at 3 ppm for less than 1 h. When both diffusive samplers were loaded with DMF and kept in fresh air, the DMF in water samplers stayed unchanged for at least for 12 h. The DMF in carbon cloth samplers showed a decay with a half-time of 14.3 h. When the carbon cloth was taken out immediately after termination of DMF exposure, wrapped in aluminum foil, and kept refrigerated, however, there was no measurable decrease in DMF for at least 3 weeks. When the air was drawn at 0.2 l/min, a breakthrough of the silica gel tube took place at about 4,000 ppm.min (as the lower 95% confidence limit), whereas charcoal tubes could tolerate even heavier exposures, suggesting that both tubes are fit to measure the 8-h time-weighted average of DMF at 10 ppm. PMID:1577523

  19. A gravimetric approach to providing SI traceability for concentration measurement results of mercury vapor at ambient air levels

    NASA Astrophysics Data System (ADS)

    Ent, Hugo; van Andel, Inge; Heemskerk, Maurice; van Otterloo, Peter; Bavius, Wijnand; Baldan, Annarita; Horvat, Milena; Brown, Richard J. C.; Quétel, Christophe R.

    2014-11-01

    Current measurement and calibration capabilities for mercury vapor in air are maintained at levels of 0.2-40 μg Hg m-3. In this work, a mercury vapor generator has been developed to establish metrological traceability to the international system of units (SI) for mercury vapor measurement results ≤15 ng Hg m-3, i.e. closer to realistic ambient air concentrations (1-2 ng Hg m-3) [1]. Innovations developed included a modified type of diffusion cell, a new measurement method to weigh the loss in (mercury) mass of these diffusion cells during use (ca. 6-8 μg mass difference between successive weighings), and a new housing for the diffusion cells to maximize flow characteristics and to minimize temperature variations and adsorption effects. The newly developed mercury vapor generator system was tested by using diffusion cells generating 0.8 and 16 ng Hg min-1. The results also show that the filter system, to produce mercury free air, is working properly. Furthermore, and most importantly, the system is producing a flow with a stable mercury vapor content. Some additional improvements are still required to allow the developed mercury vapor generator to produce SI traceable mercury vapor concentrations, based upon gravimetry, at much lower concentration levels and reduced measurement uncertainties than have been achieved previously. The challenges to be met are especially related to developing more robust diffusion cells and better mass measurement conditions. The developed mercury vapor generator will contribute to more reliable measurement results of mercury vapor at ambient and background air levels, and also to better safety standards and cost reductions in industrial processes, such as the liquefied natural gas field, where aluminum main cryogenic heat exchangers are used which are particularly prone to corrosion caused by mercury.

  20. A pilot study to assess ground-level ambient air concentrations of fine particles and carbon monoxide in urban Guatemala.

    PubMed

    Shendell, Derek G; Naeher, Luke P

    2002-11-01

    Ambient concentrations and the elemental composition of particles less than 2.5 microm in diameter (PM2.5), as well as carbon monoxide (CO) concentrations, were measured at ground-level in three Guatemalan cities in summer 1997: Guatemala City, Quetzaltenango, and Antigua. This pilot study also included quantitative and qualitative characterizations of microenvironment conditions, e.g., local meteorology, reported elsewhere. The nondestructive X-ray fluorescence elemental analysis (XRF) of Teflon filters was conducted. The highest integrated average PM2.5. concentrations in an area (zona) of Guatemala City and Quetzaltenango were 150 microg m(-3) (zona 12) and 120 microg m(-3) (zona 2), respectively. The reported integrated average PM2.5 concentration for Antigua was 5 microg m(-3). The highest observed half-hour and monitoring period average CO concentrations in Guatemala City were 10.9 ppm (zona 8) and 7.2 ppm (zonas 8 and 10), respectively. The average monitoring period CO concentration in Antigua was 2.6 ppm. Lead and bromine concentrations were negligible, indicative of the transition to unleaded fuel use in cars and motorcycles. The XRF results suggested sources of air pollution in Guatemala, where relative rankings varied by city and by zonas within each city, were fossil fuel combustion emitting hydrocarbons, combustion of sulfurous conventional fuels, soil/roadway dust, farm/agricultural dust, and vehicles (evaportion of gas, parts' wear).

  1. Polystyrene-poly(ethylene oxide) diblock copolymer: the effect of polystyrene and spreading concentration at the air/water interface.

    PubMed

    Glagola, Cameron P; Miceli, Lia M; Milchak, Marissa A; Halle, Emily H; Logan, Jennifer L

    2012-03-20

    Polystyrene-block-poly(ethylene oxide) (PS-PEO) is an amphiphilic diblock copolymer that undergoes microphase separation when spread at the air/water interface, forming nanosized domains. In this study, we investigate the impact of PS by examining a series of PS-PEO samples containing constant PEO (~17,000 g·mol(-1)) and variable PS (from 3600 to 200,000 g·mol(-1)) through isothermal characterization and atomic force microscopy (AFM). The polymers separated into two categories: predominantly hydrophobic and predominantly hydrophilic with a weight percent of PEO of ~20% providing the boundary between the two. AFM results indicated that predominantly hydrophilic PS-PEO forms dots while more hydrophobic samples yield a mixture of dots and spaghetti with continent-like structures appearing at ~7% PEO or less. These structures reflect a blend of polymer spreading, entanglement, and vitrification as the solvent evaporates. Changing the spreading concentration provides insight into this process with higher concentrations representing earlier kinetic stages and lower concentrations demonstrating later ones. Comparison of isothermal results and AFM analysis shows how polymer behavior at the air/water interface correlates with the observed nanostructures. Understanding the impact of polymer composition and spreading concentration is significant in leading to greater control over the nanostructures obtained through PS-PEO self-assembly and their eventual application as polymer templates.

  2. Comparison of Ambient Radon Concentrations in Air in the Northern Mojave Desert from Continuous and Integrating Instruments

    SciTech Connect

    David S. Shafer; David McGraw; Lynn H. Karr; Greg McCurdy; Tammy L. Kluesner; Karen J. Gray; Jeffrey Tappen

    2010-05-18

    As part of a program to characterize and baseline environmental parameters, ambient radon-222 (Rn) monitoring was conducted in the rural community of Amargosa Valley, NV, the closest community to Yucca Mountain. Passive integrating and continuous Rn monitoring instruments were deployed adjacent to the Community Environmental Monitoring Program (CEMP) station in Amargosa Valley. The CEMP station provided real-time ambient gamma exposure and meteorological data used to correct the integrated Rn measurements, verified the meteorological data collected by the continuous Rn monitoring instrument, and for provided instrumentation for evaluating the relationships between meteorological conditions and Rn concentrations. Hourly Rn concentrations in air measured by the continuous Rn monitoring instrument (AlphaGUARD®) were compared to the average hourly values for the integrating Rn measurements (E-PERM®) by dividing the total Rn measurements by the number of hours the instruments were deployed. The results of the comparison indicated that average hourly ambient Rn concentrations as measured by both methods ranged from 0.2 to 0.4 pico-curies per liter of air. Ambient Rn values for the AlphaGUARD exhibited diurnal variations. When Rn concentrations were compared with measurements of temperature (T), barometric pressure, and relative humidity, the correlation (inversely) was highest with T, albeit weakly.

  3. An assessment of indoor air concentrations and health risks of volatile organic compounds in three primary schools.

    PubMed

    Sofuoglu, Sait C; Aslan, Guler; Inal, Fikret; Sofuoglu, Aysun

    2011-01-01

    Concentrations of volatile organic compounds (VOCs), including formaldehyde, in classrooms, kindergartens, and outdoor playgrounds of three primary schools were measured in spring, winter, and fall terms in İzmir, Turkey. A health-risk assessment was conducted for odor detection, sensory irritation, chronic toxic effects, and cancer. Active sampling was applied for VOCs and formaldehyde on Tenax TA and DNPH tubes, respectively. VOCs were analyzed in a thermal desorption-GC-MS system. Formaldehyde analysis was performed using an HPLC instrument. Benzene, toluene, and formaldehyde were the most abundant compounds with 95th percentile indoor air concentrations of 29, 87, and 106 μg/m(3), respectively. Naphthalene and xylenes followed them with an order of magnitude lower concentrations. Two isomers of dichlorobenzene (1,3 and 1,4) were the other notable compounds. The concentrations were utilized to classify the indoor air pollutants with respect to potential health effects. In addition, carcinogenic and chronic toxic risks were estimated using Monte-Carlo simulation. Formaldehyde appears to be the most concerning pollutant with high chronic toxic and carcinogenic risk levels according to the health assessment followed by naphthalene, benzene, and toluene due to their chronic effects.

  4. Ambient air concentration of sulfur dioxide affects flight activity in bees

    SciTech Connect

    Ginevan, M.E.; Lane, D.D.; Greenberg, L.

    1980-10-01

    Three long-term (16 to 29 days) low-level (0.14 to 0.28 ppM) sulfur dioxide fumigations showed that exposure tothis gas has deleterious effects on male sweat bees (Lasioglossum zephrum). Although effects on mortality were equivocal, flight activity was definitely reduced. Because flight is necessary for successful mating behavior, the results suggest that sulfur dioxide air pollution could adversely affect this and doubtless other terrestrial insects.

  5. Sources, Concentrations and Risks of Naphthalene in Indoor and Outdoor Air

    PubMed Central

    Batterman, Stuart; Chin, Jo-Yu; Jia, Chunrong; Godwin, Christopher; Parker, Edith; Robins, Thomas; Max, Paul; Lewis, Toby

    2011-01-01

    Naphthalene is a ubiquitous pollutant, and very high concentrations are sometimes encountered indoors when this chemical is used as a pest repellent or deodorant. This study describes the distribution and sources of vapor phase naphthalene concentrations in four communities in southeast Michigan, USA. Outdoors, naphthalene was measured in the communities and at a near-road site. Indoors, naphthalene levels were characterized in 288 suburban and urban homes. The median outdoor concentration was 0.15 µg m−3, and a modest contribution from rush-hour traffic was noted. The median indoor long-term concentration was 0.89 µg m−3, but concentrations were extremely skewed and 14% of homes exceeded 3 µg m−3, the chronic reference concentration for non-cancer effects, 8% exceeded 10 µg m−3, and levels reached 200 µg m−3. The typical individual lifetime cancer risk was about 10−4, and reached 10−2 in some homes. Important sources include naphthalene's use as a pest repellent and deodorant, migration from attached garages, and to lesser extents, cigarette smoke and vehicle emissions. Excessive use as a repellent caused the highest concentrations. Naphthalene presents high risks in a subset of homes, and policies and actions to reduce exposures, e.g., sales bans or restrictions, improved labeling and consumer education, should be considered. PMID:22145682

  6. Concentrations and Risks of p-Dichlorobenzene in Indoor and Outdoor Air